Device for precipitation of metal films

FIELD: chemistry.

SUBSTANCE: invention relates to vacuum-plasma technology, namely to sources of metal atoms, mainly for precipitation of thin metal films in dielectric substrates in vacuum chamber, and to sources of fast atoms and molecules of gas. Installation contains vacuum chamber 1, emission grid from precipitated metal 2, hollow cathode 3, anode 4, source of discharge power supply 5, source of accelerating voltage 6, target 7 from foil of precipitated metal, which covers internal surface of cathode 3, holder 8 of substrates, covered from inside with screen 9 from foil of precipitated metal, and source of bias voltage 10, which makes it possible in case of constant flows of metal atoms and fast gas atoms to regulate the energy of the latter from zero to 1000 eV.

EFFECT: reduction of precipitated metal loss and increase of precipitated film homogeneity.

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The invention relates to a vacuum-plasma technique, namely the sources of metal atoms mainly for the deposition of thin metal films on dielectric substrates in a vacuum chamber, and to the sources of the fast gas atoms mainly for cleaning and heating the substrate in the chamber before deposition of their films with the aim of improving adhesion, and fast atom bombardment of the surface of the deposited film in order to give them the necessary properties.

Known planar magnetron, in which the flat target of the necessary sprayed metal ions from a plasma glow discharge in the arched magnetic field on the target surface, which is the cathode of the discharge. At the bombardment of the target ions, it emits electrons that are accelerated in the layer of positive space charge between the plasma and the cathode to energy eU, where U is the potential drop between the plasma and the cathode. Every electron that flew into the plasma, moving it along the segment of a circle, the perpendicular magnetic field is returned to the layer and reflected it back into the plasma. As a result, he passes through a closed polygonal curved trajectory near the surface of the target path that exceeds the dimensions of the target in hundreds and thousands of times. This allows you to maintain the discharge at a gas pressure of 0.1 to 1 PA, providing transportation sputtered, atomo is to the substrate at a distance from a target of about 0.1 m (U.S. Patent No. 3878085, 1975).

The main disadvantage of the planar magnetron is the low utilization of the target material, spray only in a small area of its surface in the area of the arched magnetic field. At the same time on the substrate is deposited a minor proportion of the powdered material, and the rest of the material is lost to the chamber walls, the holders of substrates and other structural elements of the device. Moreover, the degree of ionization of sputtered ions, metal atoms does not exceed 10%, and the concentration of the discharge plasma is reduced outside the arched magnetic field at the surface of the substrate by several orders of magnitude. It is not possible to bombard the deposited film by ions from the plasma are accelerated supplied to the substrate to a negative voltage. Therefore, to obtain a film of required properties need to use sources of ions or fast atoms and molecules.

Known sources of a wide beam of fast atoms, in which a plasma emitter ions get at a gas pressure of about 0.1 PA using a glow discharge with electrostatic confinement of electrons in the trap formed by the hollow cathode and the negative attitude of the emission grid. Ions are accelerated between the plasma emitter and a secondary plasma in the vacuum chamber, separated from each other emission grid history is nick. Mesh absorbs 20÷25% of the accelerated ions, but the rest come through its hole in the chamber and at a distance from it of about 0.1 m as a result of collisions with the gas molecules become fast atoms. The number of fast atoms bombarding the surface of the substrate located at a distance of 0.2 m from the emission grid exceeds the number of not yet preseratives ions in 10-100 times (U.S. Patent No. 6285025, 2001).

The main disadvantage of these sources is the heterogeneity of the density distribution of the equivalent current of fast atoms and molecules in the beam section.

The closest solution to the technical nature of the invention is a device for deposition of metal films with mixed flow of deposited metal atoms and bombarding the deposited metal film fast gas atoms at the bottom of the hollow cathode which has insulated from the cathode target of the deposited metal, is connected to the negative pole of the high voltage source. The metal atoms are formed by sputtering ions from the plasma emitter, at an accelerated voltage of up to several kilovolts between the anode source and a target. Sprayed the atoms pass through the plasma emitter, and then together with accelerated ions fly through the emission grid with an opacity of 80% at the camera. They are deposited on the plant and in the cell substrate, and formed as a result of charge exchange ions fast atoms continuously bombard the deposited metal film (Grigoriev S., Blizzard A.S., Isakov A.N., Miller Y.A. Deposition of hardening coatings using a universal source of accelerated particles and metal /pair/ Strengthening technologies and coatings. 2005. 9. P.36-40. Fig.2).

The disadvantage of this device are significant losses deposited on the substrate metal on the walls of the chamber, the holders of substrates and other structural elements of the device, the inability to bombard the deposited metal film fast gas atoms with energies below 100 eV, and the heterogeneity of the distribution of metal atoms and fast gas atoms on the surface of the substrate, which causes non-uniformity of the thickness and properties of the deposited film.

The technical objective of the proposed solution is the creation of a device for deposition of metal films, which would ensure no loss deposited on the substrate metal, a homogeneous distribution of the flux of metal atoms and fast gas atoms on the surface of the substrate, and the ability to adjust the energy of fast atoms from zero to 1000 eV and above.

The problem is solved in that the device for deposition of metal films containing the working vacuum chamber, Amy the pension grid, the hollow cathode, the limited emission grid, the anode inside the hollow cathode, the power source of the discharge, a positive pole connected to the anode and the negative pole - hollow cathode, an accelerating voltage source, the positive pole connected to the anode and the negative pole with the emission grid further comprises a target in the form of a shield made of a foil of the deposited metal and located on the inner surface of the hollow cathode, the emissive grid of deposited metal, hollow substrate holder installed in the working vacuum chamber opposite the emission grid, the cavity of which is equipped with a foil shield of the deposited metal, and the source voltage offset, which is the positive pole is connected with the working vacuum chamber, and the negative pole with the emission grid.

It is expedient if the device further comprises a screen mounted in the center of emission of the grid.

Optimally, if the device further comprises a rod mounted on the axis of a hollow cathode connected therewith electrically and covered with foil deposited metal.

It is expedient if the device further comprises a permanent magnet mounted on the outer surface of the hollow cathode in the center of its bottom.

The invention is illustrated by drawings, where:

Figure 1 is zobrazen diagram of the device for deposition of metal films.

Figure 2 shows a diagram of the device for deposition of metal films with a screen mounted in the center of emission of the grid.

Figure 3 shows the diagram of a device for deposition of metal films with a rod mounted on the axis of the hollow cathode and covered with foil shield of the deposited metal.

Figure 4 shows the diagram of a device for deposition of metal films with a permanent magnet mounted on the outer surface of the hollow cathode in the center of its bottom, and a rod mounted on the axis of the hollow cathode and covered with foil shield of the deposited metal.

Device for deposition of metal films contains a working vacuum chamber 1, the emission grid of deposited metal 2, the hollow cathode 3, a limited emission grid 2, the anode 4 inside the hollow cathode 3, the power supply of category 5, a positive pole connected to the anode 4, and a negative pole connected to the hollow cathode 3, the accelerating voltage source 6, a positive pole connected to the anode 4, and the negative pole is connected with the emission grid 2, the target 7 in the form of a foil shield of the deposited metal, which covers the inner surface of the hollow cathode 3, the hollow substrate holder 8 in the working the vacuum chamber 1 opposite the emission grid 2, covered inside the screen 9 of the foil of the deposited metal, and IP is the source bias voltage 10, connected with the positive pole with the working vacuum chamber 1, and the negative pole with the emission grid 2.

In addition, figure 2 shows a screen 11 mounted in the center of the emission grid 2, figure 3 shows the rod 12 mounted on the axis of the hollow cathode 3 and covered by a screen 13 of the deposited metal foil, and figure 4 shows the permanent magnet 14 mounted on the outer surface of the hollow cathode 3 in the center of its bottom.

The device operates as follows.

The working vacuum chamber 1 with a processed substrate 15 within the hollow of the substrate holder 8 is pumped out to a pressure of 1 MPa, and then served in the camera 1 working gas, for example argon, and increase the pressure in the chamber 1 to 0.5 PA. Switching on the power source 5 is applied between the anode 4 and the hollow cathode 3 voltage U_kin a few hundred volts, as measured by the voltmeter 16. Switching on the power source 6 is applied between the anode 4 and the emission grid 2 voltage U_cexceeding the voltage U_k50-150, and the difference (U_c-U_k) is measured by a voltmeter 17. Using a control device (not shown) to ignite the gas discharge between the anode 4 and the hollow cathode 3, the current in the circuit is measured by the ammeter 18. In the hollow cathode 3 is filled with plasma emitter 19 is separated from the surface of the hollow cathode 3 layer 20 positive obyemno the accelerated charge in the layer 20 of ions 21, spray the target 7 of the foil deposited metal on the inner surface of the hollow cathode 3, and separated from the emission grid 2 layer 22 positive space charge is accelerated in the layer of ions 22 and 23, the spray emission grid 2 of the deposited metal and departing through its hole in the camera 1. The resulting sputtering vapor deposited metal through the holes of the emission grid 2 comes out in the camera 1 and is deposited on the substrate 15 and the screen 9 of the deposited metal foil, covering the inner surface of the hollow holder 8 of the substrate. As a result of neutralization of the secondary electrons from the walls of the chamber 1 volumetric charge flowing through the holes of the grid 2 ions 23 and the chamber 1 is filled with a secondary plasma 24. Potential secondary plasma 24 exceeds the capacity of the camera 1 to a few volts, and the potential of the plasma emitter 19 is approximately equal to the potential of the anode 4.

Ions 23, passed through the holes of the grid 2, decelerated in the layer 25 between the grid 2 and the secondary plasma 24 and therefore fly in the plasma 24 with energy corresponding to the potential difference between the plasma emitter 19 and the secondary plasma 24, almost equal measured by the voltmeter 26 voltage between the anode 4 and immersed in the plasma 24 floating electrode 27. They face the camera 1 with the gas atoms 28 and the recharge prevrashalis the fast atoms 29, and the resulting slow ions 30 are drawn by the electric field of the plasma 24 to the grid 2 and the camera 1. Equivalent current I_pfast atoms 29 is approximately equal to measured by the ammeter 31 total current in the circuit of grid 2 and the camera 1, multiplied by the geometrical transparency of the grid 2. Separately, the current in the circuit of the camera is measured by the ammeter 32. Using power sources 6 and 10 energy fast atoms 29 can be adjusted from zero to 1 Kev and above.

To create on the surface of the substrate are centres of condensation deposited metal point defects within 5-10 minutes of support measured by the voltmeter 26 voltage from 500 to 1000 V at a current I_p~0.5 a and measured with a voltmeter 16 voltage U_kfrom 300 to 500 C. and Then by reducing the pressure of argon and/or loss measured by the voltmeter 17 voltage between the grid 2 and cathode 3 increase U_kto ~1000 C. as a result, the intensity of the sputtering target 7 and the grid 2 ions with an energy of ~1000 eV, and the flux of atoms of the deposited metal on the substrate 15 increase. By increasing the voltage source 10, as measured by the voltmeter 33, the lower the potential of the grid 2, and the result reduces measured by the voltmeter 26 energy bombarding the deposited coating atoms of argon to any desired value in the range from zero to 500 eV. When ε>500 eV argon atoms 29 location is collected from the surface of the substrate 15 all deposited metal atoms, and deposition of the metal film does not occur.

The use of targets in the form of a foil shield of the deposited metal, covering the entire inner surface of the hollow cathode, the emissive grid of the deposited metal, the hollow of the substrate holder, the cavity of which is equipped with a foil shield of the deposited metal, and a rod mounted on the axis of a hollow cathode connected to it electrically and covered with foil shield of the deposited metal, allows after deposition of metal films with the desired properties for the batch of substrates to remove the screens from the deposited metal foil made of a hollow cathode, a hollow holder of the substrate, with the surface of the rod and with the grid of the deposited metal to send them to a smelter for further use metal. Thus, loss deposited on the substrate metal can be completely excluded.

The uniformity of the plasma emitter inside the hollow cathode and a current density of ions through the emission grid provides a more uniform distribution over the surface of the substrate of the flow of fast gas atoms, and the uniformity of sputtering ions from the plasma emitter emission grid and the target in the form of a screen, covering the entire inner surface of the hollow cathode, provides a more uniform distribution over the surface of the substrate of the stream of atoms deposited m the metal.

The source bias voltage, the positive pole is connected with the working vacuum chamber, and the negative pole is connected with the emission grid, allows no violation of the homogeneity of the flow of metal atoms and fast gas atoms at a constant equivalent to the current fast atoms to regulate their energy from zero to 1000 eV and above.

Fixed in the center of the emission grid impermeable to ions and atoms of the metal screen reduces the flux density of atoms and the density of the equivalent current of fast atoms mainly in the center of the substrate, where in the absence of the screen, the flux density of atoms and the density of the equivalent current of fast atoms are maximums. This provides a more uniform distribution of the flux of metal atoms and fast gas atoms on the substrate surface.

Mounted on the axis of the hollow cathode terminal connected electrically to the cathode and covered with foil shield of the deposited metal, shifts the maximum current density of ions through the emission grid from its center at a distance R greater than the radius of the rod, r. As a result, the surface of the plasma emitter in the region between r and R is bent in such a way that passed through the mesh ions appears component of velocity directed towards the axis of the grid. This provides a more uniform distribution of fast atoms g is over the surface of the substrate. The lack of flow of metal atoms through the surface mesh, covered with a flat end face of the rod reduces the deposition rate of the metal film in the center of the substrate, and the flow of metal atoms with the sprayed ions of the screen on the cylindrical surface of the rod increases the deposition rate of the metal film on the periphery of the substrate. This provides a more uniform distribution of the flux of metal atoms and fast gas atoms on the substrate.

A permanent magnet mounted on the outer surface of the hollow cathode in the center of his bottom, allows to reduce the operating pressure of the gas and to increase the current glow discharge. This allows you to increase the deposition rate of a film on a substrate.

Compared with the prototype of the proposed device for deposition of metal films is no loss of deposited metal, the higher the uniformity of thickness deposited on a substrate of the metal film and the ability to adjust the energy of the fast gas atoms from zero to 1000 eV and above. When the diameter of the emission grid of 200 mm, the distance from it to the substrate 150 mm and the diameter of the rod on the axis of the cathode 20 mm heterogeneity thickness of the copper film on the glass substrate in the zone diameter 180 mm did not exceed ±2,5%. Score from separation sticky tape like SCOTCH tape" adhesion of copper films with a thickness of up to 4 μm, deposited on glass substrates by the Les preliminary bombardment for 5 minutes with argon atoms with an energy of 900 eV, found a detachment of the film just outside the area with a diameter of 220 mm

Analysis of the claimed technical solution for compliance with the conditions of patentability showed that specified in the independent claim, the symptoms are significant and interrelated with the formation of the sustainable population is unknown at the date of priority of the prior art required characteristics, sufficient to obtain the desired synergistic (sverhsummarny) technical result.

Thus, the above data confirm that the implementation of the use of the claimed technical solution the following cumulative conditions:

object embodying the claimed technical solution, its implementation is intended for deposition on the substrate metal films;

for the declared object in the form as it is described in the independent clause following formula, confirmed the possibility of its implementation using the above described in the application or known from the prior art on the priority date tools and methods;

object embodying the claimed technical solution, its implementation is able to achieve perceived by the applicant of the technical result.

Therefore, the claimed object meets the requirements of patentability "h the curvature", "inventive step" and "industrial applicability" under the current law.

1. Device for deposition of metal films containing the working vacuum chamber, the emission grid, hollow cathode, limited emission grid, the anode inside the hollow cathode, the power source of the discharge, a positive pole connected to the anode and the negative pole - hollow cathode, an accelerating voltage source, the positive pole connected to the anode and the negative pole with the emission grid, characterized in that it further comprises a target in the form of a shield made of a foil of the deposited metal and located on the inner surface of the hollow cathode, the emissive grid of deposited metal, hollow substrate holder installed in the working the vacuum chamber opposite the emission grid, the cavity of which is equipped with a foil shield of the deposited metal and the source bias voltage, which is positive pole is connected with the working vacuum chamber, and the negative pole with the emission grid.

2. The device according to claim 1, characterized in that it further comprises a screen mounted in the center of emission of the grid.

3. The device according to claim 1, characterized in that it further comprises a rod mounted on the axis of a hollow cathode connected to either the electrically and covered with foil shield of the deposited metal.

4. The device according to claim 1, characterized in that it further comprises a permanent magnet mounted on the outer surface of the hollow cathode in the center of its bottom.