Printing form and method of changing the wettability properties

 

The printed form can be used in the process of offset printing and represents a printing plate or printing cylinder with a semiconductor surface, which is a pattern consisting of hydrophilic and hydrophobic areas. Hydrophilic areas have chemical end groups in the first chemical state, and hydrophobic zones-chemical end groups in the second chemical state. When this first chemical state different from the second chemical state. To change the wettability properties of the printing form surface of the semiconductor lead in the first chemical state to the first property, wettability, and then transfer a partial amount of all areas of the semiconductor surface in the second chemical state to the second property of wettability by changing the chemical end groups of the semiconductor surface. And the second property wettability different from the first property of wettability. The proposed method can be applied both inside and outside of the printing machine, which allows re-use of printed forms. When using the method inside the printing machine provides a significant advantage in vremeni">

The invention relates to a method of changing the wettability properties of the printing form with the surface of the semiconductor, as well as printed form with the surface of the semiconductor, which has different characteristics, wettability, and its application in the process of offset printing.

From EP 262475 B1 is already known printing machine which is provided with a printed form, on which subject the print image can be displayed using the corresponding hydrophobic and hydrophilic areas. To ensure switching between hydrophilic, respectively, hydrophobic, a condition in separate zones on the printed form provided ferroelectric material, which can locally polarize, respectively, be depolarized. Thus, hydrophilization, respectively prehydrolysis, the printing form is carried out using the mechanism of polarization, respectively depolarization, which means to perform inside the printing machine. However, the disadvantage of this method is that the effect is based on having a large radius of action of the electrostatic forces of attraction and in accordance with this resolution subject to printing of the image is limited to the SHA No. 3678852 known printing plate, which is covered with an amorphous semiconductor. Amorphous state of the semiconductor can be changed by means of a laser beam from a disordered amorphous state to a more ordered crystalline state. In the crystalline state of the semiconductor surface is more rough, so changing the state of the semiconductor surface causes the liquid in the area of the rough surface is better kept than in the smooth amorphous zones. Resolution of the printing plate made according to this method, limited to the minimum size of the crystalline zones.

The closest technical solution according to the essential features and the achieved result is the method of changing the wettability properties of the printing form with a semiconductor surface and the printing form, is known from patent US 5206102 (publ. 27.04.1993).

The known method is that the surface of the semiconductor lead in the first chemical state to the first property of wettability. This corresponds to the printing plate or printing cylinder have a coating of hydrophilic oxide semiconductor material. Then transfer a partial amount Menno carry out local chemical treatment in partial areas of the semiconductor surface using a controlled source of energy, for example, laser, obtaining hydrophobic zones corresponding to print information. Thus the second property wettability different from the first wettability properties.

In the above patent disclosed a printed form, executed in the form of a printing plate or printing cylinder with a semiconductor surface, which is a pattern consisting of hydrophilic and hydrophobic areas and hydrophilic areas have a first chemical state, and hydrophobic zones of the second chemical with the first chemical state different from the second chemical state.

The above known method, and printed form, the inherent disadvantages of the solutions described in the prior art.

The objective of this invention is to provide an alternative local and repeatable changes in the wettability characteristics of the printing form with a semiconductor surface, and establishment of the appropriate printed form.

The problem is solved in that in the method of changing the wettability properties of the printing form with a semiconductor surface according to the invention the surface of the semiconductor lead in the first chemical state to the first property of macinaie with the second property of wettability by changing the chemical end groups of the semiconductor surface, and the second property wettability different from the first wettability properties.

Preferably the second chemical status be achieved by changing the chemical properties of the first atomic layers in the area of the semiconductor surface.

The first property wettability is hydrophilic, and a second property of the wettability of the hydrophobic, or the first property wettability is hydrophobic, and a second property of wettability is hydrophilic.

The first chemical status create by removing the layer from the semiconductor surface in atomic size, preferably using an HF solution or a solution of ammonium fluoride (AF).

The second chemical status create by local chemical treatment in partial areas of the semiconductor surface.

Should processing be performed using a controlled source of energy, which is administered so as to create a second chemical state so that it corresponds to printing of image information or the negative.

Preferably, when the controlled energy source is a laser, in particular a pulsed laser or a conventional source of energy, such as ultraviolet lamp.

Not less preference is equal to 157 nm, or excimer laser with a wavelength in the ultraviolet range308 nm, or solid state laser, such as laser yttrium aluminum garnet with nitima with wavelength355 nm.

It is desirable that the semiconductor surface was amorphous, polycrystalline or crystalline silicon, germanium or an alloy of silicon or germanium, in particular, SiGe, SiC, SiCN.

The second chemical state is carried out by the local limited changes in the chemical structure in the surface zone with a thickness up to 5 nm.

The basic idea of this invention is to modify the characteristics of wettability, i.e., the local hydrophilic or hydrophobic properties of the printing form using chemical control terminal groups of the surface with respectively different electronic properties, i.e. properties of the interaction.

To do this, first create a surface with a chemical structure, which preferably has an essentially homogeneous hydrophilic or hydrophobic properties of wettability. Then this surface is limited by the partial surfaces with locally limited isgenericciabe, accordingly, from hydrophobic to hydrophilic. In this chemical conversion process is not required to use a ferromagnetic material or to cause a change in the surface roughness, for example by crystallization. Instead wettability characteristics in some areas of the semiconductor surface control due to the fact that purposefully provide semiconductor surface hydrophilic and hydrophobic chemical end groups.

This localized the conversion process can be performed using the so-called chemical processing, when using photothermal, photochemical, or in the General case of laser-induced processes reaction is a chemical transformation.

In the preferred embodiment, as a semiconductor selected silicon. This semiconductor surface of the first transfer in a hydrophobic state, the surface include, for example, the SiH group-, SiH2and/or Si3or put them on a surface. Then to change the hydrophobic characteristics of locally replace the hydrophobic group of atoms hydrophilic group of atoms or turn it into hydrophilic, so that highest of silicon (111) surface quality of the printing form provides a special advantage, namely, that the surface is atomically smooth and hydrophilic, respectively hydrophobic end groups can be attached essentially at the same distance from each other.

To create hydrophilic, respectively hydrophobic original layer, and to convert between hydrophilic and hydrophobic condition you can use a variety of processes.

So, for example, to obtain a homogeneous hydrophilic surface can be subjected to a printing plate suitable process liquid chemical modification, which under suitable conditions it is possible to provide a strong hydrophilic wettability of the surface, which is called, for example, that in the first atomic layers of semiconducting surface underlying the SiOH group and/or SiO-. Due to the laser irradiation with a suitable wavelength, in particular, pulsed laser, locally and purposefully to make it hydrophilic property to hydrophobic by replacing hydrophilizing groups of atoms hydrophobic surface design.

However, there are also passing in the opposite direction process. To do this, first make a printed form with essentially hydrophobic surface.

For this is only the top layers of semiconductor and occurs hydrophobic, the hydrogen-terminated surface. It can again be hydrophilizing in some areas, with these areas down energy.

After use of the printing form, i.e., after printing, the entire surface is again translated to its original state. Then print the form can again be used to create the image.

Using the method according to the invention, it is possible to create a printed form on which you can re-acquire images and, thereby, to be reused in many consecutive cycles. In addition, the resolution of the printing form is not limited by the size of the crystals or electrical interaction.

The problem is solved also by the fact that in printed form, in particular, the printing plate or printing cylinder with a semiconductor surface, which is a pattern consisting of hydrophilic and hydrophobic zones, according to the invention the hydrophilic areas have chemical end groups in the first chemical state, and hydrophobic zones - chemical end groups in the second chemical with the first chemical state different from the second chemical state.

Hydrophobic zones are to be printed information or crystalline silicon, GE, or an alloy of silicon or germanium (SiGe), in particular SiC, or SiCN.

The second chemical state penetrates into the semiconductor to a depth of a maximum of 5 nm from the surface.

Further advantages and preferred modifications follow from the following description with reference to the drawings, in which:

Fig.1 is a schematic representation of the method according to the invention;

Fig.2 is a schematic diagram of a modification of the semiconductor surface from hydrophilic to hydrophobic by the example terminal SiH groups-and SiOH-.

As shown in Fig.1, the starting point of the method according to the invention is a printing form 10, which, as shown in Fig.1, may be made in the form of a printing plate or printing cylinder. Printing plate 10 has a surface layer 12 of the semiconductor, in particular silicon, which is deposited on the printed form. This original printing form after the manufacturing process is usually covered with native, i.e. not exactly certain of the oxide layer, the thickness of which is typically 1-3 nm.

In the first stage of the method according to the invention, this printed form is converted into printed form with a certain, essentially hydrophobic surface layer 14. verhnostny of the silicon atoms are saturated with hydrogen. Depending on the crystal lattice of the surface features on the surface of a semiconductor, a semiconductor, preferably silicon, may associate one or more hydrogen atoms. In the case of the crystal lattice surface (111) of silicon to each atom of silicon in accordance with this attached one hydrogen atom perpendicular to the surface (111). In the case of the crystal lattice surface (001) silicon or another can on each silicon atom on the surface to have a few free valences, so that a surface silicon atom can join two or more hydrogen atoms. Since the polycrystalline silicon surface consists of a mixture of various crystal surfaces: (111), (001) or other - it follows that, polycrystalline or amorphous semiconductor surface has a mixture of monohydride, digeridoo and trihydrides.

The above process termination with hydrogen to create a hydrophobic semiconductor surface can be realized, for example, by processing the surface of a diluted HF solution or the buffer solution of ammonium fluoride, when removed only the top layers of the semiconductor ATO is when the single crystal along the plane (111) of silicon application buffer solution NH4F (pH about 8) due to the anisotropic etching process leads to a further homogenization, i.e. atomically flat surface, which in the ideal case only has atomic steps, when polycrystalline silicon surface anisotropic etching process leads to microscopic roughness. In contrast, when the polycrystalline silicon surface with diluted HF solution removes only the oxide layer and, thus, does not change the microscopic roughness. Thus, after this stage, the printing plate 10 has a hydrophobic surface 14, which can be used for further method according to the invention.

In the next stage of the method the hydrophobic surface 14 of the printing form 10 hydrophilized (converted into hydrophilic) in partial areas of the surface. This can be accomplished, for example, by means of what be hydrophilization areas of locally subjected to chemical conversion and, thus, locally digitalout surface, and the dehydrogenated surface area occupied by the hydrophilic groups of atoms. For local modification of the surface is particularly well established in two ways. As showing obanno are suitable pulsed lasers, which have a small cross section of the beam, so that the dehydrogenation can be performed in a spatially limited area. As the laser can be applied, for example, fluorine laser in a remote region of the ultraviolet range (VUV) with a wavelength of 157 nm, if the surface modification is necessary to carry out photochemical way.

For photothermal modification, which depending on the hydride requires local heating to 300-550°C, it is possible in principle to use all lasers operating in the ultraviolet range, as for example, gas lasers (excimer laser) and solid-state lasers (such as laser yttrium aluminum garnet with neodymium with quadruple frequency).

Typically, these lasers operate from the control unit 18 through which the beam 20 of the laser 16 is printed on the form and when this is switched on and off, respectively, is ignored or filtered out, so the rest on a hydrophobic surface 14 to be applied to the printed pattern 22 or the negative of the pattern to form a hydrophobic image. This molecular change properties on the surface of the printing form is usually impossible to see with the naked eye. Applied printed image 22 is typically a line is to use all known methods of conversion into digital form of the original, as well as direct digital image creation, for example, using a graphics program or by using the digital camera.

Usually these images are then put into memory so-called raster image processor (WHEN), this memory may be located in the control unit 18 or beyond. On the basis of which is specified in the data processor, control the laser beam so that the printing form 10 is applied to the image 22. Along with this drawing by a local power supply with a laser, you can supply power on a large surface with the lamp, for example, ultraviolet lamp (in particular, using commercially available excimer lamps with different wavelengths of ultraviolet radiation). It is particularly preferably prior to exposure of the printing form to cover the printed form of the mask, so that the lamp only in certain areas can affect the surface 14 of the printing form 10.

Accordingly, by using both methods is provided by creating a hydrophobic surface 14 of the printing form 10 due to local fotoindutsirovannogo process reaction in the partial areas of the modified, second chemical state, which Ognianovo body on the surface 24, in the ideal case, the dividing line 24 separates the solid zone 26 zone 28 out of a rigid body. Each silicon atom, which lies on the line 24 to the surface, has a free valence, which in the case of hydrogen-terminated surface of the semiconductor silicon moneydriven, i.e. saturated one hydrogen atom. Due to the photoinduced process is the surface condition dehidrirana in the zone 30 and is converted into a second chemical state, which is hydrophilic. This hydrophilic state is characterized, on the one hand, the hydrophilic group of atoms that lie outside the boundary line 24 of the semiconductor, in this case IT is. It is also possible that the surface area of one or more atomic layers of semiconductor 26 will be included oxygen atoms, so that the hydrophilic wettability characteristics in these areas are additionally strengthened. Thus, the processed surface of the printing form has a first chemical state, which is hydrophobic, and the second chemical state, which is hydrophilic. Due to this different abilities attraction water printed form can be used for offset printing.

After the and, while this printing ink is especially easy to remove, since in the method according to the invention is formed on the surface only a microscopic roughness, and the difference between hydrophobic and hydrophilic state is created by the chemical composition of the surface, and lying directly beneath the surface modified zone. After removal of printing ink from the surface of the printing form, the printing form can again be transferred at the initial hydrophilic state by processing the surface by the new termination of its hydrogen, so again reached the initial state (I). This can be accomplished, for example, due to the fact that on the surface, as shown in Fig.2(II), remove the area of atomic size (a few monolayers) and then a silicon surface, which can easily saturate the hydrogen atoms.

One of the possible use of chemical method is to treat the surface with HF aqueous solution of ammonium chloride, with the help of this method removed the top layer and at the same time is the termination of the surface with hydrogen.

It is shown in Fig.method 2 refers to the silicon surface, in cotroversy is polycrystalline, i.e., that on the surface there is a mixture of various crystal planes. Due to this can be enhanced hydrophobic properties. In particular, this will appear on the surface of a silicon solid body, for example, the surface (001) and other crystals so that you can saturate the additional free valence additional hydrogen atoms.

Along with the described liquid process termination hydrogen can also be used all other methods that cause essentially complete termination hydrogen or alkylation of a silicon semiconductor surface.

The above-described stage of the method according to the invention, directed to locally hydrophilicity hydrophobic original surface. However, according to the invention, possible reverse phase method in which a hydrophilic surface by local photoinduced process is in these zones hydrophobic. To achieve this, first create a hydrophilic surface that can be implemented, for example, due to the fact that the printed form of the chemically treated liquid N2About2. Another possibility is laser induced oxidation in a humid atmosphere.

Due about the indicate along with the SiH groups is also hydrophobic group SiCH3-, SiOCH3At the expense of this printing plate is irradiated surfaces hydrophobic relative to water, and thus is suitable for the printing process.

Along with the described silicon as a semiconductor can be used as germanium or an alloy that contains germanium and silicon (SiGe), or SiC, or SiCN.

The proposed method can be applied inside and outside of the printing machine, so that for many applications offset printing produces the advantage of re-use of printed forms. In particular, when using the method inside the printing machine provides a significant advantage in time, because it is not necessary to remove the printed form.

Claims

1. How to change the wettability properties of the printing form (10) with a semiconductor surface (12), characterized in that the surface of the semiconductor lead in the first chemical state to the first property of wettability, transfer a partial amount of all areas of the semiconductor surface in the second chemical state to the second property of wettability by changing the chemical end groups of the semiconductor surface, and a second property of zmajeva is some condition is carried out by changing groups of atoms of the first atomic layers in the area of the semiconductor surface.

3. The method according to any of the p. 1 or 2, characterized in that the first property of wettability is hydrophilic, and a second property of the wettability of the hydrophobic, or the first property wettability is hydrophobic, and a second property of wettability is hydrophilic.

4. The method according to any of paragraphs.1-3, characterized in that the first chemical status create by removing layers from the surface of the semiconductor in atomic size, preferably using an HF solution or a solution of ammonium fluoride (AF).

5. The method according to any of paragraphs.1-4, characterized in that the second chemical status create by local chemical treatment in partial areas of the semiconductor surface.

6. The method according to p. 5, characterized in that the treatment is carried out using a controlled source (16) of energy, which is administered so as to create a second chemical state so that it corresponds to printing of image information (22) or its negative.

7. The method according to p. 6, characterized in that the controlled source (16) of energy is a laser, in particular a pulsed laser or a conventional source of energy, such as ultraviolet lamp.

8. The method according to p. 7, characterized in that the laser is fluorine esewani in the ultraviolet range308 nm, or solid state laser, such as laser yttrium aluminum garnet with neodymium with wavelength355 nm.

9. The method according to any of paragraphs.1-8, characterized in that the semiconductor surface is amorphous, polycrystalline or crystalline silicon, germanium or an alloy of silicon or germanium, in particular, SiGe, SiC, SiCN.

10. The method according to any of paragraphs.1-9, characterized in that the second chemical state is carried out by the local limited changes in the chemical structure in the surface zone with a thickness up to 5 nm.

11. Printing form (10), in particular, the printing plate or printing cylinder with a semiconductor surface (14), which carries a pattern consisting of hydrophilic and hydrophobic zones, characterized in that the hydrophilic areas have chemical end groups in the first chemical state, and hydrophobic zones - chemical end groups in the second chemical with the first chemical state different from the second chemical state.

12. Printed form under item 11, wherein the hydrophobic zones are subject to printing of image information (22) or its negative.

13. Printing form according to any one of starecheski silicon, GE, or an alloy of silicon or germanium (SiGe), in particular, SiC or SiCN.

14. Printing form according to any one of paragraphs.11-13, characterized in that the second chemical state penetrates into the semiconductor to a depth of a maximum of 5 nm from the surface.



 

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