Method of separating surface layer of semiconductor chip (versions)

FIELD: process engineering.

SUBSTANCE: invention relates to separation of semiconductor chip surface layer. In compliance with first version, focused laser beam is directed onto chip so that its focus is located at layer separation plane perpendicular to beam axis and displaced to scan layer separation plane in direction of chip exposed side surface and deep down to make continuous cutout. In compliance with second version, focused laser beam is directed onto chip so that focus is located in layer separation plane perpendicular to beam axis and displaced in said plane to produce non-overlapping local regions with disturbed chip structure topology and weakened atomic bonds. Said local regions are distributed over entire said plane. External effects are applied to layer being separated to destruct said weakened atomic bonds.

EFFECT: separation of lateral surface layers from semiconductor crystals.

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The technical FIELD TO WHICH the INVENTION RELATES.

Group of inventions relates to the field of laser processing of solid materials, in particular to a method for separating a surface layer of semiconductor crystals with a laser, including a laser sharp.

The LEVEL of TECHNOLOGY

Laser cutting of semiconductor crystals widely used in recent decades and is one of the main methods of separation of semiconductor device structures on separate chips (US 4224101, US 5922224). This separation can be carried out using a vertical laser cut into individual chips piece of semiconductor crystal 101, the circuit 100 which is shown in figure 1, or vertical laser cut into individual semiconductor chips washers. With the way the vertical laser cutting a focused laser beam 102 is moved in a plane parallel to its axis 103, which leads to a vertical planar section 104, parallel to the axis of the focused laser beam 103 and perpendicular to the crystal surface 105 through which the laser light enters the crystal. When focusing the laser beam on the crystal surface vertical flat section 104 is formed by thermal chemical decomposition or evaporation of the crystal in the vicinity of 106, the focus of the laser beam.

The lack of pic is BA cutting focus the beam on the crystal surface is pereosazhdeniya part of the evaporated material on the edges of the incision and micro cracks at the edges of the incision, caused by thermal stresses (US 7682937). This leads to additional consumption of expensive semiconductor material and the need to remove perezajennogo material using chemical etching, as described in patents US 4224101, US 7682937.

To avoid the resultant deposition rates of the evaporated material and the additional consumption of a semiconductor material allows way vertical laser cutting by focusing pulsed laser radiation below the upper surface of the transparent semiconductor crystal within the crystal, as proposed in patents US 7547613, US 7626137. The scheme of cutting with a laser beam focusing under the surface of the transparent semiconductor crystal 200 is shown in Figure 2. In this method, cutting plane cutting near focus positions of the laser beam creates a local region 206, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and lowered mechanical strength of the crystal. Moving the laser beam in the vertical plane 204 perpendicular to the crystal surface 105 and parallel to the axis of the focused laser beam 103, allows you to create an ordered set of local regions 206, lying in the same vertical plane 204, Figure 2. Since the mechanical strength of the vertical plane 204 with a set of local areas 06 substantially reduced, when the application of external mechanical or thermomechanical stress the crystal breaks up on this vertical plane (see US patents 7547613, US 7626137).

Methods vertical laser cutting allows to cut semiconductor crystals 101, figure 1 and figure 2, and the semiconductor spacers on separate chips, but is unable to provide the Department of semiconductor device structures on crystalline substrates in a horizontal plane or semiconductor washers from cylindrical semiconductor Boule. The present invention offers two variants of the method of separation of the surface layer of the semiconductor crystal, which allow to solve these problems.

DISCLOSURE of INVENTIONS

The present invention offers two variants of the method of separation of the surface layer of the semiconductor crystal. In one embodiment of the method the Department offer laser cutting. To do this, send a focused laser beam on the crystal so that the focus is located in the plane of the separation layer, perpendicular to the axis mentioned beam, move the laser beam with the implementation of the scanning focus plane of the separation layer in the direction from the open side surface of the crystal into forming a continuous slot, the width of which increases with each pass of the laser locatred operation is performed until the separation of the surface layer.

To separate the layer from the crystal in the form of a cylindrical boules scanning plane separation layer carried by a lateral cylindrical surface down in a spiral.

To separate the layer from the crystal in the form of a parallelepiped scanning plane separation layer perform the reciprocating movement of the beam shift on the step with the formation of a trajectory of movement of the focus in the form of a meander.

In the preferred embodiment, to prevent cracking of the crystal or crystalline bull can be preheated up to 100-1000°C.

In another embodiment, a method of separating a surface layer of a semiconductor crystal, proposed in the framework of the present invention, to generate pulsed laser radiation, and directing a focused laser beam on the crystal so that the focus is located in the plane of the separation layer, perpendicular to the axis mentioned beam, move the laser beam so that the focal point moves in the plane of the separation layer with the formation of non-overlapping local regions with disturbed topology crystal structure and weak interatomic bonds, these local areas are distributed throughout the mentioned plane. Then to the detachable layer exert external influence, destroying mentioned weak interatomic with the connection.

External exposure may be mechanical or thermo-mechanical.

Thermo-mechanical effects can be created with the use of metal plates attached to the outer surface of the detachable layer, and heating to a temperature of 50-1000°C. the Distance between the centers of the mentioned non-overlapping local regions may be 0.03 to 0.3 of the thickness of the detachable layer.

The present invention differs from the existing analogue presented on figure 1 and figure 2 so that the laser beam is always focused below the surface of the crystal and its focus is moved in a horizontal plane parallel to the crystal surface through which the laser beam enters the crystal and perpendicular to the focused laser beam (hereinafter, this plane is also referred to as lateral).

In the first variant of the method in the plane of the separation layer (plane section) thermal chemical decomposition or evaporation of the crystal in the vicinity near the focus of the laser beam, and this plane is parallel to a detachable surface of the crystal. Thus, the proposed method allows to cut the semiconductor crystals and boules, separating the superficial layers from semiconductor crystals, semiconductor washers from cylindrical semiconductor Boule. Applied to poluprovodn the protein crystals and cylindrical semiconductor boules grown with surface instrumentation structures proposed method allows to separate the thin semiconductor layers and semiconductor thin washers with grown-counter structures from semiconductor crystals and cylindrical semiconductor Boule.

In the second variant of the method when using short laser pulses, the average power thermal chemical decomposition or evaporation of the crystal in the vicinity near the focus of the laser beam does not occur, the laser beam creates a local region, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal.

In this case, moving the focus of the laser beam in the horizontal plane parallel to the crystal surface through which the laser beam enters the crystal and perpendicular to the axis of the cone of the focused laser beam, leads to the formation in the plane of the separation layer of the set of non-overlapping local regions with disturbed structure of chemical bonds, which lies beneath a detachable crystal surface at a depth determined by the depth of focus of the laser beam. Since the mechanical strength of the crystal in the plane of the Department with a set of local areas significantly weakened, with application of an external mechanical or thermomechanical stress the crystal breaks up on the plane with the separation of the surface layer lying above or below the plane from the population depending on the depth of focus of the laser beam.

The method of separation according to the second variant allows you to cut semiconductor crystals and boules lateral separating surface layers from semiconductor crystals, semiconductor washers from cylindrical semiconductor boules without loss of semiconductor material. In application to semiconductor crystals and cylindrical semiconductor boules grown with surface instrumentation structures of the second variant of the method allows to separate the thin semiconductor layers and semiconductor thin washers with grown-counter structures from semiconductor crystals and cylindrical semiconductor boules, respectively.

Variants of the method of separation of the surface layer of a semiconductor chip (hereinafter also used the term "laser cutting") in accordance with the present invention allows the separation plane surface layers from semiconductor crystals, in particular the surface layers with semiconductor device structures from semiconductor crystals. In addition to the proposed methods allow to separate the semiconductor washers from cylindrical semiconductor boules, including semiconductor thin washers with the instrument structures.

BRIEF DESCRIPTION of DRAWINGS

The present invention is illustrated in the drawings, n which are represented in the prior art - Figure 1 and figure 2, and different implementations of the present invention - Figure 3-14.

Figure 1 presents a diagram illustrating known from the prior art method vertical laser cutting a semiconductor crystal using a powerful focused laser radiation, leading to thermal chemical decomposition or evaporation of the crystal in the vicinity of the focus of the laser beam.

Figure 2 presents a diagram illustrating known from the prior art method vertical laser cutting a semiconductor crystal using a focused pulsed laser radiation, which creates a local region in the vertical plane.

Figure 3 presents a diagram illustrating a first variant of the method of separation of the surface layer of the semiconductor crystal.

Figure 4 presents a diagram illustrating a first variant of the method of separating a thin semiconductor layer below the top surface of the grown instrument structure from a semiconductor crystal.

Figure 5 presents a diagram illustrating a first variant of the method of separating a thin semiconductor layer containing at the base of the instrument grown structure from a semiconductor crystal.

Figure 6 presents a diagram illustrating a second variant of the method of the separation surface is restage layer of a semiconductor crystal.

Figure 7 presents a diagram illustrating a second variant of the method of separating a thin semiconductor layer below the top surface of the grown instrument structure from a semiconductor crystal.

On Fig presents a diagram illustrating a second variant of the method of separating a thin semiconductor layer containing at the base of the instrument grown structure from a semiconductor crystal.

Figure 9 presents a diagram illustrating a first variant of the method of separation of the surface layer of the semiconductor on semiconductor boules washers.

Figure 10 presents a diagram illustrating a first variant of the method of separating a thin semiconductor washers, contains under the top surface of the instrument grown structure from the semiconductor boules.

Figure 11 presents a diagram illustrating a first variant of the method of separating a thin semiconductor washers, containing at the base of the instrument grown structure from the semiconductor boules.

On Fig presents a diagram illustrating a second variant of the method of separation of the surface layer of the semiconductor on semiconductor boules washers.

On Fig presents a diagram illustrating a second variant of the method of separating a thin semiconductor washers, containing below the top surface virasena the instrument structure, from the semiconductor boules.

On Fig presents a diagram illustrating a second variant of the method of separating a thin semiconductor washers, containing at the base of the instrument grown structure from the semiconductor boules.

The IMPLEMENTATION of the INVENTION

The present invention will be clarified below with a few examples of variants of its implementation. It should be noted that the following description of these embodiments is only illustrative and not exhaustive.

In the present invention for implementing the method uses a laser with a wavelength λ lying in the region of relative transparency semiconductor, namely between the edge of the main absorption region of residual rays.

Preferably, the wavelength λ of the laser beam lies in the interval 2πħ/Eg≤λ≤c/ν0where Eg- the width of the forbidden zone for the cut semiconductor, ν0- frequency optical phonon for the cut semiconductor, C is the speed of light, ħ is the Planck constant.

From the above inequality it follows that the preferred wavelength of the laser for lateral semiconductor laser cutting of silicon, germanium and gallium arsenide lies in the range 0.8 μm ≤ λ ≤ 20 μm, for gallium nitride in the range of 0.35 μm ≤ λ ≤ 10 μm and aluminum nitride in the range 02 µm ≤ λ ≤ 8 ám.

Example 1. Figure 3 shows a diagram 300 illustrating a first variant of the method on the example of the separation of the surface layer of a semiconductor crystal of gallium nitride. To do this, use Nd:YAG laser operating in the modulated mode q-switched, frequency-doubled and generating light pulses with a wavelength of λ=532 nm, energy of 5 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2.

Under the action of the beam 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal 101 gallium nitride, focused below the top surface 105 of the crystal at a depth of 100 μm, is the local heating of the crystal to a temperature above 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam. Moving the focus of the laser beam 102 with a speed of 1.5 cm/s in the horizontal (lateral) plane parallel to the front surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to a consistent decomposition of gallium nitride and increase the width of the lateral section 304 from left to right deep into the crystal. Upon reaching the lateral incision 304 right g is unity crystal figure 3 the continuity of the crystal 101 is broken and the upper layer 307, lying above section 304, is separated from the main crystal. To prevent cracking of the crystal gallium nitride resulting from thermal stresses, laser cutting is performed at a temperature Tp=600°C.

Example 2. 4 shows a diagram 400 illustrating a first variant of the method by the example of separating a thin semiconductor layer below the top surface of the led grown structure AlGaN/InGaN/AlGaN, from a semiconductor crystal. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with energy of 5 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal 101 gallium nitride and the led structure 407 AlGaN/InGaN/AlGaN, focused under the surface 105 of the crystal at a depth of 50 μm, is the local heating of the crystal to a temperature above 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam. Moving the focus of the laser beam 102 with a speed of 1.5 cm/s in the horizontal plane parallel to the surface is 105 crystal, through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to a consistent decomposition of gallium nitride and increase the width of the slit 304 in a horizontal plane from left to right deep into the crystal. Upon reaching the lateral incision 304 the right edge of the crystal in figure 4, the continuity of the crystal 101 is broken and the upper layer 307 with led grown structure 407 AlGaN/InGaN/AlGaN, lying above section 304, is separated from the main crystal. To prevent cracking of the crystal gallium nitride due to thermal stresses laser cutting is performed at a temperature Tp=600°C.

Example 3. Figure 5 shows a diagram 500 illustrating a first variant of the method by the example of separating a thin semiconductor layer containing at the base of the led grown structure of GaN/InGaN/GaN, a semiconductor crystal.

To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with energy of 5 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2. Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal 101 gallium nitride, but absorbing the I in the led structure 407 GaN/InGaN/GaN, focused deep below the top surface 105 of the crystal, is the local heating of the crystal to a temperature above 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam. Moving the focus of the laser beam 102 with a speed of 1.5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to a consistent decomposition of gallium nitride and increase the width of the lateral section 304 from left to right deep into the crystal. Upon reaching the lateral incision 304 the right edge of the crystal figure 5 the continuity of the crystal 101 is broken and the bottom layer 307 with led grown structure 407 GaN/InGaN/GaN underlying section 304, is separated from the main crystal.

Example 4. Figure 6 shows a diagram 600 illustrating a second variant example of the separation of the surface layer of a semiconductor crystal of gallium arsenide. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at the wavelength of λ=1064 nm and generates pulses with energy of 0.1 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 2 μm, which provides the density the energy the AI of 2.5 j/cm 2.

Under the action of radiation 102 Nd:YAG laser with a wavelength of λ=1064 nm, weakly in which people absorb guided crystal 101 gallium arsenide, focused below the top surface 105 of the crystal at a depth of 100 μm, the formation of non-overlapping local regions 206, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal. Moving the focus of the laser beam 102 with a speed of 1 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to the formation of in-plane 604 branch, which lies beneath the surface 105 of the crystal at a depth determined by the depth of focus of the laser beam 102, the set of non-overlapping local regions 206. The average distance between the local areas is 10 μm. When scanning and moving the focused laser beam 102 in a horizontal plane from left to right square plane 604 Department with a set of local regions 206 increases from left to right deep into the crystal until it reaches the right edge of the crystal at the 6. Laser processing is performed at ambient temperature Tp=20°C.

The process of laser processing ends who I am. Then the crystal 101 is bonded to the upper surface 105 on an aluminum plate and heated to a temperature of 100-500°C. however, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of gallium arsenide and aluminum, crystal 101 is split by mechanically weakened plane 604 with the Department of the lateral surface of the layer lying above the plane 604, from the main crystal of gallium arsenide.

Example 5. Figure 7 shows a diagram 700 illustrating a second variant of the method by the example of separating a thin semiconductor layer below the top surface of the led grown structure AlGaN/InGaN/AlGaN from the semiconductor crystal.

To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with an energy of 50 NJ, duration of 5 NS and a repetition frequency of 10000 Hz. The laser beam is focused to a spot diameter of 1 μm, which provides an energy density of 5 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal 101 gallium nitride and the led structure 407 AlGaN/InGaN/AlGaN, focused under the surface 105 of the crystal at a depth of 50 μm, the formation of non-overlapping local regions 206, which disturbed the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal. Moving the focus of the laser beam 102 at a speed of 5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to the formation in the lateral plane 604 branch, which lies beneath the surface 105 of the crystal at a depth determined by the depth of focus of the laser beam 102, the set of non-overlapping local regions 206. The average distance between the local areas is 5 μm. When scanning the focus of the laser beam 102 in a horizontal plane from left to right square plane 604 with a set of local regions 206 increases from left to right deep into the crystal until it reaches the right edge of the crystal 7. Laser processing is performed at ambient temperature Tp=20°C.

The process of laser processing ends. Then the crystal 101 is bonded to the upper surface 105 on an aluminum plate and heated to a temperature of 100-500°C. however, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of gallium nitride and aluminum, crystal 101 is split by mechanically weakened pleskot the 604 with the Department of the lateral surface layer 407 with led structure 407 AlGaN/InGaN/AlGaN, lying above the plane 604, from the main crystal of gallium nitride.

Example 6. On Fig shows a diagram 800 illustrating a second variant of the method by the example of separating a thin semiconductor layer containing at the base of the led grown structure of GaN/InGaN/GaN, a semiconductor crystal.

To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with an energy of 50 NJ, duration of 5 NS and a repetition frequency of 10000 Hz. The laser beam is focused to a spot diameter of 1 μm, which provides an energy density of 5 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal 101 gallium nitride, but which people absorb guided in the led structure 407 GaN/InGaN/GaN, focused deep below the surface 105 of the crystal, the formation of non-overlapping local regions 206, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal. Moving the focus of the laser beam 102 at a speed of 5 cm/s in the horizontal plane parallel to the crystal surface 105 through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to the formation in the lateral regions of the second plane 604, which lies beneath the surface 105 of the crystal at a depth determined by the depth of focus of the laser beam 102, the set of non-overlapping local regions 206. The average distance between the local areas is 5 μm. When scanning the focus of the laser beam 102 in a horizontal plane from left to right square in the lateral plane 604 with a set of local regions 206 increases from left to right deep into the crystal until it reaches the right edge of the crystal at Fig. Laser processing is performed at ambient temperature Tp=20°C.

The process of laser processing ends. Then the crystal 101 is glued to the bottom surface 105 on an aluminum plate and heated to a temperature of 100-500°C. however, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of gallium nitride and aluminum, crystal 101 is split by mechanically weakened plane 604 with the Department of the lower lateral layer 307 with led grown structure 407 GaN/InGaN/GaN lying below the plane 604, from the main crystal of gallium nitride.

Example 7. Figure 9 shows a diagram 900 illustrating a first variant of the method on the example of the separation of the surface layer of the semiconductor cylindrical gallium nitride boules. To do this, use Nd:YAG laser, the slave is melting mode modulated q-factor at wavelength λ=532 nm and generates pulses with energy of 5 µj, duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, focused under the surface 105 at a depth of 200 μm, cylindrical boules 901 gallium nitride, is the local heating of the crystal to a temperature above 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam.

Moving the focus of the laser beam 102 in a spiral with a speed of 1.5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis of the focused laser beam 103, leads to a consistent decomposition of gallium nitride and increase the width of the lateral section 304 in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Upon reaching the lateral incision 304 axis of the cylindrical boules figure 9 continuity cylindrical boules 901 gallium nitride broken and washer 902 gallium nitride, lying above section 304, is separated from the cylindrical gallium nitride boules. To prevent cracking detachable washer gallium nitride due to thermal stresses laser cutting is performed at a temperature Tthe =600°C.

Example 8. Figure 10 shows a diagram 1000 illustrating a first variant of the method by the example of separating a thin semiconductor washers, contains under the top surface of the led grown structure AlGaN/InGaN/AlGaN, from cylindrical semiconductor boules gallium nitride. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with energy of 5 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal gallium nitride in the led structure 407 AlGaN/InGaN/AlGaN, focused under the surface 105 at a depth of 50 μm, cylindrical boules 901 gallium nitride, is the local heating of the crystal to a temperature above 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam.

Lateral displacement of the focus of the laser beam 102 in a spiral with a speed of 1.5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to follow atelinae decomposition of gallium nitride and increase the width of the lateral section 304 in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Upon reaching the lateral incision 304 axis of the cylindrical boules figure 10 b of the cylindrical boules 901 gallium nitride broken and washer 902 with locally grown gallium nitride led structure 407 AlGaN/InGaN/AlGaN, lying above section 304, is separated from the cylindrical gallium nitride boules. To prevent cracking detachable washer gallium nitride due to thermal stresses laser cutting is performed at a temperature Tp=600°C.

Example 9. Figure 11 shows a diagram 1100 illustrating a first variant of the method by the example of separating a thin semiconductor washers, containing at the base of the led grown structure of GaN/InGaN/GaN, from cylindrical semiconductor boules gallium nitride.

To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with energy of 5 µj, pulse duration of 5 NS and repetition rate of 1000 Hz. The laser beam is focused to a spot diameter of 16 mm, which provides an energy density of 2 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal gallium nitride, but which people absorb guided in the led structure 407 GaN/InGaN/GaN, focused deep below the surface 105, a cylindrical boules 901 gallium nitride, is the local heating of the crystal to power the market higher than 900°C, leading to chemical degradation of the crystal gallium nitride on gaseous nitrogen and liquid gallium in the vicinity of 106 the focus of the laser beam. Spiral lateral displacement of the focus of the laser beam 102 with a speed of 1.5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis of the cone of the focused laser beam 103, leads to a consistent decomposition of gallium nitride and increase the width of the lateral section 304 in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Upon reaching the lateral incision 304 axis of the cylindrical boules on 11 continuity cylindrical boules 901 gallium nitride broken and washer 902 with locally grown gallium nitride led structure 407 GaN/InGaN/GaN underlying section 304, is separated from the cylindrical gallium nitride boules.

Example 10. On Fig shows a diagram 1200 illustrating a second variant of the method by the example of separating the washer from cylindrical semiconductor boules crystal aluminum nitride. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with an energy of 50 NJ, duration of 5 NS and a repetition frequency of 10000 Hz. The laser beam is focused to a spot diameter of 1 μm, which ensures that the density is the power of 5 j/cm 2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, focused to a depth of 100 μm under the surface 105, a cylindrical boules 901 aluminum nitride, is formed non-overlapping local regions 206, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal. Moving the focus of the laser beam 102 at a speed of 5 cm/s in the horizontal plane, parallel to the surface 105 of the crystal through which the laser beam enters the crystal and perpendicular to the axis 103 of the focused laser beam, leads to the formation in the lateral plane 604, which lies beneath the surface 105 of the crystal at a depth determined by the depth of focus of the laser beam 102, the set of non-overlapping local regions 206. The average distance between the local areas is 5 μm. The focus of the laser beam 102 is moved in a horizontal plane in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Square plane 604 with a set of local regions 206 increases from the periphery into the crystal to the axis of the cylindrical boules. When the focus axis of the cylindrical boules process of laser processing ends. Laser processing is performed at ambient temperature Tp=20°C.

C is the cylindrical Buhl 901 crystal aluminum nitride is glued to the upper surface 105 on an aluminum plate and heated to a temperature of 100-500°C. However, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of aluminum nitride and aluminum, cylindrical Buhl 901 crystal aluminum nitride split by mechanically weakened plane 604 separating washer 902 aluminum nitride, lying above the plane 604 from the main cylindrical boules aluminum nitride.

Example 11. On Fig presents a diagram 1300 illustrating a second variant of the method by the example of separating a thin semiconductor washers, contains under the top surface of the led grown structure AlGaN/InGaN/AlGaN, from cylindrical semiconductor boules gallium nitride. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with an energy of 50 NJ, duration of 5 NS and a repetition frequency of 10000 Hz. The laser beam is focused to a spot diameter of 1 μm, which provides an energy density of 5 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal gallium nitride in the led structure 407 AlGaN/InGaN/AlGaN, focused at a depth of 50 μm under the surface 105 of the cylindrical boules, the formation of non-overlapping local regions 206, which disrupted the structure of chemical bonds, weakened helices the first interaction between atoms and reduced mechanical strength of the crystal. The focus of the laser beam 102 at a speed of 5 cm/s is moved in a horizontal plane in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Square plane 604 with a set of non-overlapping local regions 206 increases from the periphery into the crystal to the axis of the cylindrical boules. The average distance between regions is 5 μm. When the focus of the laser beam 102 axis of the cylindrical boules process of laser processing ends. Laser processing is performed at ambient temperature Tp=20°C.

Then the cylindrical Buhl 901 crystal gallium nitride is glued to the upper surface 105 on an aluminum plate and heated to a temperature of 100-500°C. however, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of gallium nitride and aluminum, cylindrical Buhl 901 crystal aluminum nitride split by mechanically weakened plane 604 separating washer 902 with locally grown gallium nitride led structure 407 AlGaN/InGaN/AlGaN, lying above the plane 604, from the main cylindrical gallium nitride boules.

Example 12. On Fig presents a diagram 1400 illustrating a second variant of the method by the example of separating a thin semiconductor washers, containing at the base of the led grown structure of GaN/InGaN/GN, from cylindrical semiconductor boules gallium nitride. To do this, use Nd:YAG laser operating in the mode of modulated q-factor at wavelength λ=532 nm and generates pulses with an energy of 50 NJ, duration of 5 NS and a repetition frequency of 10000 Hz. The laser beam is focused to a spot diameter of 1 μm, which provides an energy density of 5 j/cm2.

Under the action of radiation 102 Nd:YAG laser with wavelength λ=532 nm, weakly in which people absorb guided crystal gallium nitride, but which people absorb guided in the led structure of GaN/InGaN/GaN 407, focused deep below the surface of the bulls 105, the formation of non-overlapping local regions 206, which disrupted the structure of chemical bonds, weak chemical interaction between atoms and reduced mechanical strength of the crystal. The focus of the laser beam 102 is moved at a speed of 5 cm/s in the horizontal plane in a spiral from the periphery into the crystal to the axis of the cylindrical boules. Square plane 604 with a set of non-overlapping local regions 206 increases from the periphery into the crystal to the axis of the cylindrical boules. The average distance between the local areas is 5 μm. When reaching the focused laser beam 102 axis of the cylindrical boules process of laser processing ends. Laser processing is performed at room t is mperature T p=20°C.

Then the cylindrical Buhl 901 crystal gallium nitride is glued to the bottom surface 105 on an aluminum plate and heated to a temperature of 100-500°C. however, due to the resulting thermo-mechanical stress associated with the difference in the coefficients of thermal expansion of gallium nitride and aluminum, cylindrical Buhl 901 crystal aluminum nitride split by mechanically weakened plane 604 separating washer 902 with locally grown gallium nitride led structure 407 GaN/InGaN/GaN lying below the plane 604, from the main cylindrical gallium nitride boules.

Although the present invention has been described and illustrated by examples of embodiments of the invention, it should be noted that the present invention is by no means the case is not limited to the given examples.

1. The method of separation of the surface layer of the semiconductor crystal, characterized in that:
- direct the focused laser beam on the crystal so that the focus is located in the plane of the separation layer, perpendicular to the axis mentioned
ray,
- move the laser beam with the scanning of the focus in the plane of the separation layer in the direction from the open side surface of the crystal into forming a continuous slot to the opposite side surface with getting naru is placed in the continuity of the crystal and the separating layer.

2. The method according to claim 1, characterized in that the separation layer from the crystal in the form of a cylindrical boules scanning focus in the plane of the separation layer carried by a lateral cylindrical surface down in a spiral.

3. The method according to claim 1, characterized in that the separation layer from the crystal in the form of a parallelepiped scanning focus in the plane of the separation layer perform the reciprocating movement of the beam shift on the step with the formation of a trajectory of movement of the focus in the form of a meander.

4. The method according to claim 1, characterized in that the crystal or crystalline Buhl pre-heated to 100 to 1000°C.

5. The method of separation of the surface layer of the semiconductor crystal, characterized in that:
- generate pulsed laser radiation,
- direct the focused laser beam on the crystal so that the focus is located in the plane of the separation layer, perpendicular to the axis mentioned beam,
- move the laser beam so that the focal point moves in the plane of the separation layer with the formation of non-overlapping local regions with disturbed topology crystal structure and weak interatomic bonds, these local areas are distributed throughout the mentioned plane,
- detachable layer exert external influence, destroying at manatee weak interatomic bonds.

6. The method according to claim 5, characterized in that exert a mechanical effect.

7. The method according to claim 5, characterized in that the applied thermomechanical action.

8. The method according to claim 7, characterized in that thermo-mechanical effect created with the use of metal plates attached to the outer surface of the detachable layer, and heating to a temperature of 50-1000°C.

9. The method according to claim 5, characterized in that the distance between the centers of the mentioned non-overlapping local regions is 0.03 to 0.3 on the thickness of the detachable layer.



 

Same patents:

FIELD: process engineering.

SUBSTANCE: proposed method comprises placing plate to be polished in etching chemical solution. Note here that said plate is secured to vacuum holder by plate non-working side while plate working side in downed into said solution. Said plate is rotated about its axis and, simultaneously, moved regularly along the circuit.

EFFECT: uniform polishing.

5 dwg, 3 ex

FIELD: physics, semiconductors.

SUBSTANCE: invention refers to semiconductor engineering. Substance of the invention: method of round silicon carbide wafer fabrication consists in monocrystal calibration, slicing, grinding, bevelling, annealing and polishing. Polishing process is four-staged: coarse polishing with coarse-grain diamond paste, fine polishing with fine-grain diamond paste, nanopolishing with silicasol suspension containing "detonation" nanodiamonds with grain size nor exceeding 1 mcm, nanopolishing with silicasol suspension not containing solid abrasive particles.

EFFECT: fabrication of polished silicon carbide wafer surfaces of roughness less than 0,5 nm.

2 cl

FIELD: electric engineering.

SUBSTANCE: in method of photo-template stocks production that includes mechanical processing of glass plates with application of polishing powder on the basis of cerium dioxide and polishing cloth made of nonwoven material, which consists of working and adhered layer, treatment in water solutions of organic acids, treatment in neutral water medium, application of masking layer and resist, additionally between working and adhered layers of polishing cloth internal reinforcing layer is formed with the following ratio of thicknesses: adhered layer - reinforcing layer - working layer 2.0-2.5:1:1.5-2.0.

EFFECT: method allows to increase output of proper photo-template stocks by improvement of polishing cloth structure during polishing of glass plates by formation of additional reinforcing layer between polishing and adhered layers.

1 tbl

FIELD: precision grinding.

SUBSTANCE: proposed precision grinding device has rotation unit for setting object to be ground in rotary motion and first support carrying first rotation unit; second rotation unit for rotating grinding wheel and second support carrying second rotation unit for setting grinding wheel in rotary motion; means for controlling displacement at first or second support that incorporates first displacement-controlling part that functions to move first or second support and second part used to control movement of, and to apply pressure to, support so as to make the latter move in direction of displacement; in the process displacement of first or second support and that of first or second rotation unit can be regulated by way of selective use of first and second movement-control parts; spatial position control device disposed between first rotation unit and first support or between second rotation unit and second support; spatial position control device affords spatial position control for first or second rotation unit.

EFFECT: enhanced precision of grinding operation.

6 cl, 7 deg

FIELD: treatment of silicon mono-crystals grown by Czochralski method, possibly manufacture of mono-crystalline silicon chips- members of solar batteries and integrated circuits.

SUBSTANCE: method comprises steps of pseudo-squaring of silicon mono-crystal for further grinding ribs of pseudo-squared ingot; cutting mono-crystals by chips. Ribs are ground alternatively; each rib is ground layer by layer in motion direction of tool and in parallel relative to lengthwise axis of ingot.

EFFECT: improved quality of mono-crystalline silicon chips due to safety of near-contour region of worked zone of ingot, lowered material (silicon) losses at working ingots.

3 cl, 1 ex, 1 tbl, 3 dwg

FIELD: electronic engineering; mechanical treatment of materials for electronic-engineering and parts made of them, including semiconductor and ferrite materials.

SUBSTANCE: proposed diamond-containing disk that can be used in particular for machining hybrid and monolithic microwave integrated circuits and their components which needs high quality and high precision of process to keep within their small dimensions and to avoid chipping on them has grain size specified by material being treated and base of its diamond-containing material is hard material. Disk is built of at least two alternating layers of diamond-containing material with damping sublayer in-between connected to them, thickness of this sublayer being equal to 1/10 - 2/3 of diamond-containing material grain size.

EFFECT: enhanced yield and quality of materials and parts machined with aid of disk, enlarged service life of the latter.

1 cl, 1 dwg, 1 tbl

FIELD: semiconductor technological processes, namely production of semiconductor plates with use of mechanical working and chemical etching.

SUBSTANCE: method comprises steps of placing semiconductor plate on surface of polishing wheel; supplying liquid polishing composition onto surface of wheel while acting by means of ultrasonic oscillations upon working surfaces of working tips of piezoelectric oscillation systems; providing oscillation amplitude of working tips sufficient for finely spraying of liquid polishing composition; forming large number of drops of aerosol of liquid polishing composition; determining means size and number of drops according to condition of receiving necessary quantity of polishing composition on surface of polishing wheel and providing it by selecting resonance dimension of oscillation system; setting shape and size of working tip of oscillation system and number of outlet openings in it working surface according to condition of forming spraying torch with lengthwise size on surface of polishing wheel no less than diameter half of polishing wheel.

EFFECT: possibility for providing uniform and equally planar surface of semiconductor plate due to applying guaranteed quantity of polishing composition onto each spot of polishing wheel surface.

5 dwg

FIELD: semiconductor engineering.

SUBSTANCE: proposed method is meant to manufacture semiconductor devices used for treatment of undersides of structures with finished chips as well as to produce original silicon, germanium, and other wafer-substrates. Wafers to be treated are secured on head. The latter and tool are set in rotary motion, and polishing mixture is fed to treatment area. Tool used for treatment has intermittent polyurethane working layer and runs at speed of 1400-2000 rpm; wafer-carrying head rotates at speed of 300-550 rpm with specific pressure of 250-350 G/cm2 applied to surface being treated. Polishing mixture used for the purpose incorporates diamond powder with grain size of 5-1 μm, domestic detergent, silica powder, and glycerin , volume ratio of glycerin to detergent being 3:1 - 4:1, that of silica powder to glycerin-detergent mixture, 1:1 - 2:1, and of diamond powder to general composition, 8-9 g per liter. Droplets of thinner in the form of water are fed to surface being treated.

EFFECT: enhanced quality and productivity of process, improved environmental friendliness, enlarged functional capabilities.

2 cl, 4 dwg, 1 tbl, 3 ex

FIELD: mechanical engineering; devices and methods for separation of materials.

SUBSTANCE: the invention is pertaining to the device and the method for separation of materials, in particular, to monocrystals. The technical result of the invention is effective purification and removal of the stripped material during the cutting. For this purpose the device contains: a rotary cutter with a concentric hole, the edge of which forms the cutting edge, at that the rotary cutter is made with a capability of rotation around its central shaft for cutting of the material; a position device intended for positioning of the material subjected to cutting in respect to the rotary cutter in such a manner, that during the cutting process the cutting disk is moving across the material making rotation for cutting-off a separate plate; a device for feeding a lubricating-cooling liquid onto the rotary cutting disk and a device for feeding a gaseous medium onto the rotary cutting disk. At that the device for feeding the gaseous medium has a nozzle, which is mounted inside the concentric hole and is designed in such a manner, that the gaseous medium is fed onto the edge in the direction perpendicular to central shaft of the rotary cutting disk. The method provides for feeding of the lubricating-cooling liquid only onto the outlet side of the cutting disk if to look in the direction of its rotation behind the place of the rotary cutting disk pass through the material. At that the rotary cutting disk is subjected to cooling during operation of the cutting, and the plate is cooled only after operation of the cutting after the separate plate has been cut off during operation of the cutting. At that during the cooling operation the lubricant-cooling liquid is fed by the batching amounts, and during the stripping operation the lubricant-cooling liquid is fed in the bigger amount as compared with the indicated above amount.

EFFECT: the invention ensures the effective purification and removal of the stripped material during the cutting operation.

12 cl, 6 dwg

FIELD: electronic industry.

SUBSTANCE: proposed method for producing photomask blanks includes mechanical treatment of glass wafers using cerium dioxide based polishing powders and nonwoven material based polishing cloth, their treatment in aqueous solutions of organic acids, treatment in neutral water medium followed by dehydration, drying, and check-up. Mechanical treatment is conducted at proportion of polishing power effective diameter, diameter of synthetic fibers of nonwoven cloth and its volume density being 1 : 2-4 : 0.2-0.3 with cerium dioxide content in polishing powder being minimum 80 mass percent. Cerium dioxide to ferric oxide ratio and sum of neodymium and praseodymium oxides can be chosen between 1 : 0.05 and 0.08 : 0.1-0.2.

EFFECT: reduced cost of photomask blank due to reducing number of mechanical treatment stages and optimal choice of proportions in parameters of materials used for mechanical treatment.

2 cl, 1 tbl

The invention relates to the cutting of laminated glass and can be used on glass factories that manufacture laminated glass

FIELD: process engineering.

SUBSTANCE: proposed method may be used in nuclear power engineering and other branches of machine building. Proposed method comprises focusing laser beam at material and feeding protective inert gas into cutting zone. Inert gas is fed via nozzle at its outlet pressure of, at least, 3.5·10-5 MPa. Note here that laser beam with wavelength of 1.06-1.07 mcm is used and directed via said nozzle coaxially with its lengthwise axis.

EFFECT: higher efficiency and quality, ruled out metal corrosion.

2 cl, 1 dwg, 2 ex

FIELD: process engineering.

SUBSTANCE: method of moulding cells for vessels or bottles for bottle washing machines. Proposed method comprises the following stages: moulding cell blank 3a from synthetic material and machining it. Said machining includes material removal or dissection to produce structures required for functioning and/or hardening cell 3, and/or for reducing weight of said cell.

EFFECT: higher strength and quality of complex cells.

9 cl, 5 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to metal machining by laser beam. Proposed method comprises stages described below First step comprises making first bore with initial diameter and bore axis. Second step comprises displacing laser beam and rotating it about bore axis to produce intermediate bore aligned with initial bore but with larger diameter. Third step comprises displacing laser beam focus along bore axis and finishing said bore by pulsed laser beam.

EFFECT: boring in composite material with ceramic substrate, for example in gas turbine engine combustion chamber or vane.

11 cl, 6 dwg

FIELD: metallurgy.

SUBSTANCE: plate (7) is positioned parallel to first plate (5) and at close distance from it so, that outline of orifice (73a) is located opposite to outline of cut-out orifice (53a). Protective device (10) in form of plate of specific thickness with the third orifice (10a) and with outline set off inside relative to outline of second orifice (73a) is placed between two plates (5 and 7). Further, the first orifice is cut out.

EFFECT: prevention of melt metal hitting second orifice, of deviation of laser beam at cutting and of losses of density of laser beam power output.

7 cl, 4 dwg

Cutting tool // 2417879

FIELD: process engineering.

SUBSTANCE: invention relates to cutting tools and may be used for cutting whatever materials. Proposed cutting tool comprises top and bottom parts that may be parted by separating appliances. At least, one of top and bottom parts comprises cutting device while top and bottom parts are retained together by magnets made up of first and second magnetic appliances arranged on top and bottom parts. Metal strip is arranged atop the cutting tool to joint first and second magnetic appliances to, at least, top or bottom part. Invention covers also the method of cutting with the help of above described tool.

EFFECT: improved control over cutting tool, better quality of cutting.

24 cl, 25 dwg

FIELD: medicine.

SUBSTANCE: method is realised by formation of hole for introduction and fixation of one ligature end in butt end surface of surgical needle without eye, made from stainless steel. Hole is made by irradiation of butt end of needle working piece, whose diametre is from 6 to 20 mcm larger than diametre of surgical needle, which constitutes less than 150 mcm, due to irradiation by one pulse of laser ray of specified duration, isolated from pulse radiated by laser, after which section, whose diametre is larger than needle diametre is removed. In other version of method duration of pulse separated from pulse radiated by laser is equal or less than 35 mcs. In third version of method realisation pulse, isolated from pulse radiated by laser if formed by multiple pulses of short duration.

EFFECT: group of inventions will make it possible to create holes of satisfactory quality in butt end of thin surgical needle, without puncture of side wall or hole bending.

4 cl, 5 dwg, 1 tbl

FIELD: electricity.

SUBSTANCE: pulse of ultrafast laser with picosecond or shorter pulse width is associated by time and spatially with a pulse of at least one auxiliary laser that differs from ultrafast laser. Auxiliary laser pulse is controlled in such a manner that it could change in time. In this process, material condition to be processed is changed reversibly using one auxiliary laser beam and changed irreversibly when auxiliary laser beam ultrafast laser beam are associated by time and spatially. Auxiliary laser generator includes electronic communication device which modifies laser beam pulse in time and focusing optical system for spatial association of ultrafast laser beam focal point generated by ultrafast laser generator with focal point of auxiliary laser beam associated with time and for focusing ultrafast laser beam and auxiliary laser beam.

EFFECT: increase in speed of ultrafast laser processing with ultrahigh accuracy.

8 cl, 6 dwg

FIELD: mechanics.

SUBSTANCE: invention is related to hole fabrication methods and may find application in turbine component parts manufacture. Holes are arranged in a multilayer system containing at least a single metal substratum and an external ceramic layer by way of at least a single laser pulse ray. The hole is arranged in several stripping stages by way of long and short pulses. At one of the initial stripping stages one uses pulses whose duration differs from that at one of the last stripping stages. Long pulses duration exceeds 0.4 ms. With long pulses the laser output power is several hundreds W such as 500 W.

EFFECT: improved precision of holes fabrication in layered systems.

41 cl, 18 dwg

FIELD: process engineering.

SUBSTANCE: invention can be used in aircraft engineering. Adapter for working head of the device intended for making holes by laser beam comprises beam focusing appliance, mirror and device to feed auxiliary medium for laser beam. Said adapter has first laser beam inlet hole and second pulse laser beam outlet hole. Beam focusing appliance is arranged ahead of second pulse laser beam outlet hole. Mirror is arranged on laser beam optical path behind said focusing appliance so that outlet beam forms with inlet beam the angle smaller than 180°. Device to feed auxiliary medium for laser beam allows said medium to pass through said second hole along laser beam direction.

EFFECT: higher accuracy of holes produced by laser beam.

9 cl, 4 dwg

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