ES2400933T3 - Engraving pastes for inorganic surfaces - Google Patents

Abstract

Printable, homogeneous, particle-free etching medium, which is already effective at temperatures of 150°C and/or, if necessary, is activated by energy input for etching glass surfaces, selected from the group of glasses based on carbon oxide. silicon and silicon nitride-based glasses, characterized in that it is an etching paste with non-Newtonian flow behavior, which contains a) at least one etching component, selected from the group of fluoride, bifluoride and tetrafluoroborate, in an amount of 2 - 20% by weight based on the total mass, b) solvent in an amount of 10 - 90% by weight based on the total mass c) polymers based on acrylate units or functionalized vinyl and/or cellulose/cellulose derivatives, selected from the ethyl-, hydroxypropyl-, hydroxyethylcellulose group, and salts of cellulose glycolates, including sodium carboxymethylhydroxyethylcellulose or starch derivatives selected from the sodium carboxymethyl starch group , starch ether as thickening agent in an amount of 0.5 - 25% by weight based on the total mass and d) optionally, organic and/or inorganic acids in an amount of 0 - 80% by weight based on the total mass, as well as appropriate e) additives such as defoamers, thixotropic agents, flow control agents, adhesion promoters in an amount of 0 - 5% by weight on the total mass

Description

Engraving pastes for inorganic surfaces

The present invention relates to new engraving means in the form of printable, homogeneous, particle-free engraving pastes with non-Newtonian flow behavior for the engraving of inorganic, glass, amorphous or crystalline surfaces, in particular glass or ceramic , preferably systems based on SiO2 or silicon nitride, as well as the use of these engraving means.

Inorganic surfaces are understood to consist of oxidic silicon compounds containing nitride, in particular silicon oxide and silicon nitride surfaces.

Definition of glass:

Glass is understood as a uniform mass, for example quartz glass, window glass, borosilicate glass, as well as thin layers of these materials, which are obtained on other substrates (eg ceramics, metal plates, silicon wafers ) through different procedures known to the specialist in the field (CVS, PVD, rotation coating, thermal oxidation, among others).

Glass is then understood as the materials containing silicon oxide and silicon nitride, which exist in an amorphous state of aggregation without efflorescence of the glass components and in the microstructure have a high degree of disorder due to a lack of order of long-range.

In addition to pure SiO2 glass (quartz glass), all glasses are included (eg doped glasses such as borosilicate, phosphosilicate, borophosphosilicate glasses, tinted, opaline, glass, optical glasses), containing SiO2 and other components, in particular elements such as p. ex. calcium, sodium, aluminum, lead, lithium, magnesium, barium, potassium, boron, beryllium, phosphorus, gallium, arsenic, antimony, lanthanum, zinc, thorium, copper, chromium, manganese, iron, cobalt, nickel, molybdenum, vanadium, titanium, gold, platinum, palladium, silver, cerium, cesium, niobium, tantalum, zirconium, neodymium, praseodymium, which appear in the glass in the form of oxides, carbonates, nitrates, phosphates, sulfates and / or halides or act as elements of doping in glasses. Doped glasses are, e.g. ex. borosilicate, phosphosilicate, borophosphosilicate glasses, tinted, opaque, glass and optical glasses.

Silicon nitride may also contain other elements, such as boron, aluminum, gallium, indium, phosphorus, arsenic or antimony.

Definition of systems based on silicon oxide and silicon nitride:

As silicon oxide based systems, all crystalline systems which are not under the definition indicated above of amorphous SiO2 glasses and which are based on silicon dioxide are defined below, which may in particular be the salts and esters of orthosilicic acid and its condensation products - generally designated as silicates by the specialist in the field - as well as quartz and glass ceramics.

In addition, other systems based on silicon oxide and silicon nitride are included, in particular the salts and esters of orthosilicic acid and its condensation products. In addition to pure SiO2 (quartz, tridymite, cristobalite), all SiO2-based systems that are formed by “discrete” and / or linked SiO4 tetrahedra, such as p. ex. nesosilicates, sorosilicates, cyclosilicates, pyroxenes, amphiboles, phyllosilicates, tectosilicates and contain other components, in particular elements / components such as p. ex. calcium, sodium, aluminum, lithium, magnesium, barium, potassium, beryllium, scandium, manganese, iron, titanium, zirconium, zinc, cerium, yttrium, oxygen, hydroxyl groups, halides.

As silicon nitride-based systems, all crystalline and partially crystalline systems (mostly called microcrystalline) are defined below, which do not fall within the definition given above of amorphous silicon nitride layers / glasses. These include Si3N4 in its modifications a-Si3N4 and �-Si3N4 and all layers SiNx-, SiNx: H crystalline and partially crystalline. Crystalline silicon nitride may also contain other elements, such as boron, aluminum, gallium, indium, phosphorus, arsenic or antimony.

one.

 Engraving of structures on glass

Through the use of etching agents, that is, chemically aggressive compounds, decomposition of the material exposed to the attack of the etching medium occurs. For this purpose, not only the first layer of the attack surface is attacked and removed, but also - contemplated from the attack surface - layers arranged deeper.

2.

 Engraving of glass structures based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride

Depending on the state of the art, any structure can be etched selectively on silicon oxide and silicon nitride based glasses and other systems based on silicon oxide and silicon nitride and / or their surfaces and their variable thickness layers directly by procedures of laser-assisted engraving, or after masking by wet chemistry procedures [1, 2] or dry etching. [3]

In the laser-assisted engraving process, the laser beam scans the entire engraving pattern point by point on the glass, which requires, in addition to a high degree of precision, considerable adjustment and time-consuming effort.

The wet and dry chemical etching procedures contain process stages with high material use and costly in time and money:

A. Masking areas that do not have to be recorded, p. ex. through:

 Photolithography: Preparation of a negative or positive of the etching structure (depending on the varnish), varnishing the substrate surface (eg by rotating varnishing with a liquid photosensitive resin), drying the photosensitive resin, exposure to the varnished surface light of the substrate, developed, washed and, if necessary, dried.

B. Engraving structures by:

 immersion procedure (eg wet etching in wet chemical banks): immersion of the substrate in the etching bath, etching process, multiple washing in H2O cascade sink, drying

 Rotating coating procedure or spraying procedure: The etching solution is applied on a rotating substrate, the etching process can be carried out without / with energy input (eg IR or UV irradiation), then wash and drying

 dry etching procedure as p. ex. Plasma etching on expensive vacuum installations or etching with reactive gases in continuous flow reactors

[1] D.J. Monk, D.S. Soane, R.T. Howe, Thin Solid Films 232 (1993), 1

[2] J. Bühler, F.-P. Steiner, H. Baltes, J. Micromech. Microeng 7 (1997), R1

[3] M. Köhler „Ätzverfahren für die Mikrotechnik“ [Engraving process for microtechnology], Wiley VCH 19983.

3. Engraving on the entire surface of glasses based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride

In order to etch glass based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride and their layers of varying thickness throughout the surface to a certain depth, wet etching procedures are mainly used. Glasses based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride and their layers of varying thickness are immersed in etching baths that mostly contain the toxic and strongly corrosive hydrofluoric acid and other acids minerals as etching components.

The disadvantages of the engraving procedures described are based on the stages of the process with high costs of time, material and expenses and partially expensive from a technical and safety point of view and performed discontinuously.

From US 4,921626 A1 a composition for glass etching is known which contains 2-4% by weight of xanthan for viscosity adjustment and 16-30% by weight of ammonium bifluoride as an etching component. In addition, this composition contains 20-24% by weight of propylene glycol and 45-60% by weight of water. In each case this composition contains at least 45% by weight of water. This composition is suitable for the engraving of identification symbols, such as serial numbers on vehicle windows, although it is not suitable for printing uniform thin lines at the scale of m, such as those required in the semiconductor industry and heliotechnics. Compositions such as those described in this patent produce irregular and interrupted engraving lines in printing with a correspondingly high decomposition.

From WO 98/30652, a composition for deoxidizing aluminum surfaces is also known which is suitable for removing aluminum oxide deposits from aluminum surfaces. These compositions are particularly suitable for the treatment of aircraft and vehicle surfaces on rails. They consist of at least one component that releases fluoride ions, a component that releases an acid with a constant high ionization such as HF, a component for viscosity regulation, an anionic surfactant, a non-ionic surfactant, a hydrotopic agent, a coloring substance, a biocide and an oxidizing agent. These compositions are formulated in a way that ensures good wetting and good spread on the treated surfaces. However, they are not suitable for printing in the form of homogeneous thin lines or structures at scale! M on silicon oxide or silicon nitride surfaces, through which the corresponding uniform thin engraved structures can then be obtained.

Therefore, it is an object of the present invention to provide glass etching compositions based on silicon oxide or silicon nitride, which can be selectively printed homogeneously on said surfaces in simple etching processes with highest yields possible, so that through the use of these compositions in wet etching processes so far common in semiconductor technology, the application and structuring of a photoresist layer can be saved, so that an essentially more economical engraving can be obtained.

Therefore, printable, homogeneous, particle-free printing pastes, which have a non-Newtonian flow behavior and their use for etching of inorganic surfaces, in particular glass surfaces based on silicon oxide and nitride are subject to the invention. of silicon and other systems based on silicon oxide and silicon nitride and their layers of varying thickness.

It is also the object of the invention to use these homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior - in comparison with the usual dry and wet process in the aqueous and / or gas phase - in etching procedures. more affordable cost printing, suitable for high flow rates, continuously achievable, as well as technologically simple, for glass and other systems based on silicon dioxide and silicon nitride.

Preparation, modeling and subsequent treatment, such as p. ex. Grinding, polishing, lapping, heat treatment of SiO2-based systems are irrelevant - as in glass - for the use described according to the invention of printable, homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior.

The invention relates to both etching of substrates coated with SiO2 or silicon nitride in the form of homogeneous solid porous and non-porous solids (eg glass grains, glass dust, glass plates, moons, hollow glass, sintered glass ), obtained p. ex. from glass smelting, as well as the engraving of layers of porous and non-porous glass of variable thickness that is produced on other substrates (eg ceramics, metal plates, silicon wafers) by different procedures known to the specialist in the field (eg CVD, PVD, rotation coating of precursors containing Si, thermal oxidation, ...).

Engraving pastes are applied in a single process stage on the surface of the substrate to be etched. Thus, the surface to be etched can be a surface or part of a surface in a solid porous or non-porous solid homogeneous body of a glass based on silicon oxide or silicon nitride and other systems based on silicon oxide and silicon nitride (eg the surface of a silicon oxide glass) and / or a surface or part of a surface in a porous and non-porous layer of glass and other systems based on silicon oxide and silicon nitride on a material of support.

An appropriate technique for the application of the etching paste on the surface of the substrate to be etched with a high degree of automation and performance is the printing technique. Procedures known by the specialist are especially the techniques of screen printing, printing by clichés, pad printing, printing, inkjet. A manual application is also possible.

Depending on the configuration of the sieve, template, cliché, seal and pattern control, it is possible to apply printable, homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior described according to the invention over the entire surface or selectively according to the pattern of engraving structure, only in the places where an engraving is desired. All masking and lithography stages are suppressed as described in A). The engraving process can be carried out with or without energy input, e.g. ex. in the form of thermal radiation (with IR rays). After etching, the printable, homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior, are removed from the etched surface by washing with a suitable solvent and / or calcining.

By varying the following quantities, the engraving depths can be adjusted in glasses based on silicon oxide and silicon nitride and / or other systems based on silicon oxide and silicon nitride and their layers of varying thickness, and on the engraving structure selective additionally the sharpness of contours of the recorded structures:

concentration and composition of engraving components

concentration and composition of the solvents used

5 concentration and composition of the thickener system

concentration and composition of the acids added if necessary

concentration and composition of additives added as appropriate, such as defoamers, thixotropic agents, flow control agents, deaerators, adhesion promoters

the viscosity of the printable, homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior described according to the invention

duration of engraving with or without energy input on inorganic surfaces and their printed layers with the corresponding engraving pastes and

contribution of energy in the printed system with the engraving paste.

The duration of engraving according to the purpose of application, the desired engraving depth and / or the sharpness of

15 desired contours of engraving structures, is between a few seconds and several minutes. In general, an engraving duration is set between 1 - 15 min.

The printable, homogeneous, particle-free engraving pastes, which exhibit a non-Newtonian flow behavior described according to the invention are - in comparison with the liquid, dissolved or gas-shaped etching agents, such as inorganic mineral acids of the group of hydrofluoric acid, fluoride, HF gas and SF6– from

20 advantageous way, essentially simpler and safer to handle and save engraving agent.

Printable, homogeneous, particle-free engraving pastes, described according to the invention, which exhibit a non-Newtonian flow behavior are composed of:

to.

 an etching component for glass and other systems based on SiO2 and its layers

b.

 solvent

25 c. thickener

d.

 where appropriate organic (s) and / or inorganic acid (s)

and.

 if necessary, additives such as defoamers, thixotropic agents, flow control agents, deaerators, adhesion promoters

The etching effect of printable, homogeneous, particle-free engraving pastes, described according to the

The invention, with a non-Newtonian flow behavior on glass surfaces based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride is based on the use of component solutions containing fluoride with or without addition of acid, in particular solutions of fluorides, bifluorides, tetrafluoroborates such as, for example, ammonium, alkali, antimony fluoride, ammonium bifluoride, alkali, calcium, alkylated ammonium tetrafluoroborate, potassium, as well as mixtures thereof. These engraving components are effective

35 in etching pastes at temperatures in the range of 15-50 ° C, in particular at room temperature, and / or activated by energy input, for example by thermal radiation by IR rays (up to approx. 300 ° C), UV radiation or To be.

The proportion of engraving components used is in a concentration range of 2-20% by weight, preferably in the range of 5-15% by weight, based on the total mass of engraving paste.

The solvent may represent the main component of the etching paste. The proportion can be found in the range of 10-90% by weight, preferably in the range of 15-85% by weight, based on the total mass of etching paste.

Appropriate solvents may be inorganic and / or organic solvents or mixtures thereof. Appropriate solvents that can be used pure or in the appropriate mixtures may be, depending on the purpose of use:

Water

mono or polyhydric alcohols, such as p. ex. ethylene glycol, diethylene glycol, dipropylene glycol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, glycerin, 1,5-pentanediol, 2-ethyl-1-hexanol or mixtures thereof

ketones such as p. ex. acetophenone, methyl-2-hexanone, 2-octanone, 4-hydroxy-4-methyl-2-pentanone or 1-methyl-2-pyrrolidone

ethers such as ethylene glycol monobutyl ether, triethylene glycol monomethyl ether, diethylene glycol monobutyl ether or dipropylene glycol monomethyl ether

carboxylates such as [2,2-butoxy- (ethoxy)] -ethyl acetate

esters of carbonic acid such as propylene carbonate

mineral inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid or nitric acid or organic acids having an alkyl moiety chain length of n = 1-10, or mixtures thereof. The alkyl moiety can be both straight chain and branched. In particular, the organic carboxylic, hydroxycarboxylic and dicarboxylic acids such as formic acid, acetic acid, lactic acid, oxalic acid indicated above are suitable.

These solvents or mixtures thereof are also suitable, among others, once the engraving has been carried out, to remove the engraving medium again and, if necessary, wash the etched surface.

The viscosity of printable, homogeneous, particle-free engraving pastes, with a non-Newtonian flow behavior described according to the invention, is achieved by cross-linking thickeners that swell in the liquid phase, and can be modified according to the scope of application. wanted. The printable, homogeneous, particle-free engraving pastes, with a non-Newtonian flow behavior described according to the invention, comprise all etching pastes that do not have any constancy of viscosity by shear rate, in particular engraving pastes with effect shear reducer. The net formed by the thickening agent breaks under the shear load. The network reconstruction can be carried out without delay (engraving pastes of viscous structure with plastic or pseudoplastic flow behavior) or with delay (engraving pastes with thixotropic flow behavior).

Printable, homogenous, particle-free engraving pastes with a non-Newtonian flow behavior are completely homogeneous with the addition of thickening agents. No thickeners are used in particle form, such as p. ex. acrylic or silicone resins in particle form.

The possible thickening agents are polymers based on the following monomer units:

glucose units

-

Cellulose / cellulose derivatives selected from the group ethyl-, hydroxypropyl-, hydroxylethylcellulose and salts of the cellulose glycolic acid ether, including sodium carboxymethylhydroxylethylcellulose

-

starches / starch derivatives selected from the group of carboxymethyl sodium starch and starch ethers, or anionic heteropolysaccharides

acrylate units

-

functionalized methacrylate units, in particular cationic methacrylate / methacrylamide such as Borchigel® A PK

functionalized vinyl units, that is,

-

polyvinyl alcohols with different degrees of hydrolysis, in particular Mowiol® 47-88 (partially hydrolyzed, i.e. vinyl acetate and vinyl alcohol units) or Mowiol® 56-98 (fully hydrolyzed)

-

polyvinylpyrrolidones (PVP), in particular PVP K-90 or PVP K-120

Thickeners can be used alone or in combination with other thickeners.

The proportion of thickening agent necessary for the precise adjustment of the viscosity range and fundamental for the formation of a printable paste is in the range of 0.5-25% by weight, preferably 3 -20% by weight based on the mass 5 total engraving paste.

As already described, the etching pastes according to the invention with the addition of a thickening agent are also completely homogeneous. They do not contain thickeners in particle form, such as p. ex. acrylic or silicone resins in particle form.

Organic and inorganic acids whose pKa value is between 0 - 5 can be added to pasta

10 printable, homogeneous, particle-free engravings, with a non-Newtonian flow behavior described according to the invention. Inorganic mineral acids such as p. ex. hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, as well as organic acids that have a chain length of alkyl moieties of n = 1-10, improve the etching effect of printable, homogeneous, particle-free engraving pastes, with a non-Newtonian flow behavior. The alkyl moiety of organic acids can be both straight chain

As branched, in particular, organic carboxylic, hydroxycarboxylic and dicarboxylic acids such as formic acid, acetic acid, lactic acid, oxalic acid or other suitable are suitable. The proportion of the acid (s) can be found between 0-80% by weight based on the total mass of etching paste.

Defoamers, such as p. ex. which can be obtained under the trade name TEGO® Foamex N,

20 thixotropic agents such as BYK® 410, Borchigel® Thixo2,

flow control agents such as TEGO® Glide ZG 400,

deaerators such as TEGO® Airex 985 and

Adhesion promoters such as Bayowet® FT 929.

These can positively influence the printing capacity of the etching paste. The proportion of additives is in the range of 0-5% by weight based on the total mass of the etching paste.

Areas of application for engraving pastes according to the invention are, for example, in

the solar cell industry (photovoltaic components such as solar cells, photodiodes)

semiconductor industry

glass industry

30 high performance electronics

The new printable, homogeneous, particle-free engraving pastes, with a non-Newtonian flow behavior described according to the invention, can be used in any place where an engraving on the entire surface and / or structured glass surfaces is desired. based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride, as well as their layers.

35 Thus entire surfaces can be etched but also selectively individual structures in porous and non-porous solid homogeneous glasses and other porous and non-porous solid homogeneous systems based on silicon oxide and silicon nitride to the desired depth, that is, the etching process It can comprise all the intervals between the microstructural scratching (including transparent glass with light scattering effect) passing through grinding / matting effects, until the engraving of engraving structures more

40 deep (eg markings, ornaments / patterns). The fields of application are, e.g. ex .:

the manufacture of observation windows for armor, measuring devices of all kinds

the manufacture of glass supports for outdoor applications (eg for solar cells and thermal collectors)

glass surfaces engraved in the medical and sanitary field, as well as for decorative purposes, including artistic and architectural applications

Engraved glass containers for cosmetic items, food products, beverages

specific etching of glass and other systems based on silicon oxide for marking and identification purposes, e.g. ex. for marking / identification of container glass and flat glass

specific etching of glass and other silicon oxide based systems for mineralogical, geological and microstructural tests

In particular the procedures of screen printing, printing by clichés, pad printing, printing, inkjet are appropriate techniques for the application of engraving pastes. In general, in addition to the aforementioned printing procedures, a manual application is also possible (eg with a brush).

In addition to the industrial application, engraving pastes are also suitable for DIY and hobby requirements.

Printable, homogeneous, particle-free engraving pastes, with a non-Newtonian flow behavior described in accordance with the invention, can be used wherever glass layers and other silicon oxide based systems have to be etched, as well. as systems based on silicon nitride of varying thickness, over the entire surface and / or structured. The fields of application are, e.g. ex .:

Complete etching stages in glass layers based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride, which lead to the manufacture of photovoltaic components such as solar cells, photodiodes and the like, these being in particular

a) the removal of layers of silicon oxide, doped silicon oxide (eg phosphor glass after doping n of solar cells) and silicon nitride

b) the selective opening of passivation layers of silicon oxide and silicon nitride for the production of dual stage selective emitters (after opening, additional doping to obtain n + + layers) and / or p + - Back-Surface- Local Fields (BSF)

c) Engraving edges of solar cell plates coated with silicon oxide and / or silicon nitride

Complete etching stages in glass layers based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride, which lead to the manufacture of semiconductor components and circuits and require the selective opening of passivation layers of silicon oxide and silicon nitride

Complete etching stages in glass layers based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride, leading to the manufacture of components in high performance electronics

In particular the procedures of screen printing, printing by clichés, pad printing, printing, inkjet are appropriate techniques for the application of engraving pastes. In general, in addition to the mentioned printing procedures, a manual application is also possible.

In addition to the industrial application, engraving pastes are also suitable for DIY and hobby requirements.

Examples

For a better understanding and to illustrate the invention, examples that are within the framework of protection of the present invention are presented below, although they are not suitable for limiting the invention to these examples.

Example 1

21 g ethylene glycol monobutyl ether

39 g 35% NH4HF2 solution

30 g formic acid (98-100%)

5 10 g PVP K-120

In a PE container, ethylene glycol monobutyl ether and formic acid are introduced. Next, a 35% aqueous solution of NH4HF2 is added. Then the successive addition of PVP K-120 is carried out under stirring (at least 400 rpm). During the addition and approx. 30 min later, continue stirring intensely. The filling in the container is done after a short rest time. The resting time is necessary so that they can be

10 Disperse the bubbles formed in the etching paste.

This mixture results in an etching paste with which glass based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride and their layers can be specifically etched, over the entire surface or in structures, with and / or without energy input to a desired depth.

Engraving speed determined photometrically on a layer of silicon oxide obtained

15 thermally amounts to 120 nm / min for engraving the entire surface. The etching speed determined photometrically on a layer of silicon nitride (breaking rate n = 1.98) obtained by PE-CVD amounts to 70 nm / min for the entire surface etching.

The engraving paste obtained is stable to storage, easy to handle and can be printed. You can delete p. ex. with water from printed material or paste holder (sieve, scraper, template, seal, cliché,

20 cartridge, etc.) or can be removed by calcination in the oven.

Example 2

22 g triethylene glycol monomethyl ether

43 g solution at 35% NH4HF2

20 g deionized water

25 12 g PVP K-120

Triethylene glycol monomethyl ether is provided and as in Example 1 all liquid components are added under stirring. Finally, the thickening agent PVP K-120 is introduced successively under stirring (at least 400 rpm). During the addition and approx. 30 min later, continue stirring intensely. The filling in the container is done after a short rest time. The resting time is necessary for the dispersion of the

30 bubbles formed in the engraving paste.

This mixture results in an etching paste with which glass based on silicon oxide and silicon nitride and other systems based on SiO2 and silicon nitride and their layers, on the entire surface or in structures, can be etched, with and / or without energy input to a desired depth.

The etching rate determined photometrically on a thermally obtained silicon oxide layer is 106 nm / min for the entire surface etching.

The engraving paste obtained is stable to storage, easy to handle and can be printed. You can delete p. ex. with water from the printed material or paste holder (sieve, scraper, template, seal, cliché, cartridge, etc.) or can be removed by calcination in the oven.

Example 3

40 12 g solid NH4HF2

142 g lactic acid

10 g ethylcellulose

36 g ethylene glycol monobutyl ether

The ethyl cellulose is successively mixed with ethylene glycol monobutyl ether at 40 ° C in a previously arranged water bath. The solid NH4HF2 is dissolved in lactic acid also under stirring and then added to the ethyl cellulose master paste. 5 Both parts together are stirred for 2 hours at 600 rpm.

This mixture results in an etching paste with which glass based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride and their layers can be specifically etched, over the entire surface or in structures, with and / or without energy input to a desired depth.

The etching rate determined photometrically on a layer of thermally obtained silicon oxide amounts to 23 nm / min for the engraving of the entire surface.

The engraving paste obtained is stable to storage, easy to handle and can be printed. You can delete p. ex. with acetone or butyl acetate of the printed material or paste holder (sieve, scraper, template, seal, cliché, cartridge, etc.)

or it can be removed by calcination in the oven.

Example 4

15 15 g ethylene glycol monobutyl ether

15 g triethylene glycol monomethyl ether

29 g propylene carbonate

72 g formic acid

46 g 35% NH4HF2 solution

20 24 g PVP K-90

The solvent mixture and formic acid are introduced into a PE container. Next, a 35% aqueous solution of NH4HF2 is added. Then the successive addition of PVP K-120 is carried out under stirring (at least 400 rpm). During the addition and approx. 30 min later, continue stirring intensely. The filling in the container is done after a short rest time. The resting time is necessary so that they can be

25 Disperse the bubbles formed in the etching paste.

This mixture results in an etching paste with which glass based on silicon oxide and silicon nitride and other systems based on silicon oxide and silicon nitride and their layers can be specifically etched, over the entire surface or in structures, with and / or without energy input to a desired depth.

Engraving speed determined photometrically on a layer of silicon oxide obtained

30 thermally amounts to 67 nm / min for selective etching of structures of approx. 80 μm wide. The etching rate determined photometrically on a layer of silicon nitride obtained by PE-CVD amounts to 35 nm / min for the selective engraving of structures of approx. 100 μm wide and an engraving temperature of 40 ° C.

The engraving paste obtained is stable to storage, easy to handle and can be printed. It can

35 delete p. ex. with water from the printed material or paste holder (sieve, scraper, template, seal, cliché, cartridge, etc.) or can be removed by calcination in the oven.

Claims (20)

1. Printable, homogeneous, particle-free etching medium, which is already effective at temperatures of 15 to 50 ° C and / or if necessary activated by means of energy input for the engraving of glass surfaces, selected from the group of glasses based on silicon oxide and glasses based on silicon nitride, characterized in that it is an etching paste with non-Newtonian flow behavior, which contains a) at least one etching component, selected from the group of fluoride, bifluoride and tetrafluoroborate, in an amount of 2-20% by weight based on the total mass, b) solvent in an amount of 10-90% by weight based on the total mass c) polymers based on functionalized acrylate or vinyl units and / or cellulose / cellulose derivatives, selected from the ethyl-, hydroxypropyl-, hydroxyethylcellulose group, and salts of cellulose glycolate, including sodium carboxymethylhydroxy ethyl cellulose or starch derivatives selected from the starch group of sodium carboxymethyl, starch ether as a thickening agent in an amount of 0.5-25% by weight over the total mass and d) where appropriate, organic and / or inorganic acids in an amount of 0 - 80% by weight over the total mass, as well as if necessary e) additives such as defoamers, thixotropic agents, flow control agents, adhesion promoters in an amount of 0-5% by weight over the total mass

2.

Printable etching medium according to claim 1 for glass surfaces, characterized in that as a thickening agent it contains polymers based on acrylate or functionalized vinyl units and anionic heteropolysaccharides.

3.

Printable etching medium according to claim 1 or 2 for glass surfaces, whose elements are selected from the group calcium, sodium, aluminum, lead, lithium, magnesium, barium, potassium, beryllium, boron, beryllium, phosphorus, gallium, arsenic, antimony , lanthanum, scandium, zinc, thorium, copper, chromium, manganese, iron, cobalt, nickel, molybdenum, vanadium, titanium, gold, platinum, palladium, silver, cerium, cesium, niobium, tantalum, zirconium, yttrium, neodymium and praseodymium .

Four.

Engraving medium according to claim 1 or 2, characterized in that it contains at least one inorganic and / or organic acid, the recording component (s) being present in a concentration of 2 to 20% by weight based on the mass total.

5.

Engraving medium according to claim 4, characterized in that the engraver component (s) are in a concentration of 5 to 15% by weight, based on the total mass.

6.

Engraving medium according to claims 1 and 4, characterized in that as a recording component it contains at least one fluorine compound selected from the group of ammonium fluoride, alkali, antimony, ammonium bifluoride, alkali, calcium, alkylated potassium ammonium tetrafluoroborate Y,

if necessary, at least one inorganic mineral acid selected from the group of hydrochloric acid, phosphoric acid, sulfuric acid or nitric acid and / or, if necessary, at least one organic acid, which may have a straight or branched chain alkyl moiety with 1-10 C atoms, selected from the group of alkylcarboxylic acids, hydroxycarboxylic acids and dicarboxylic acids.

7.

Engraving medium according to claim 1 or 4, characterized in that it contains an organic acid selected from the group of formic acid, acetic acid, lactic acid and oxalic acid.

8.

Engraving medium according to claims 1 to 6, characterized in that the proportion of organic and / or inorganic acids is in a concentration range of 0 to 80% by weight based on the total amount of medium, with the acids added respectively a pKa value between 0 and 5.

9.

Engraving medium according to claim 1 or 2, characterized in that water, mono or polyhydric alcohols, such as glycerin, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, are used as solvent. 2-ethyl-1hexenol, ethylene glycol, diethylene glycol and dipropylene glycol, as well as its ethers such as ethylene glycol monobutyl ether, triethylene glycol monomethyl ether, diethylene glycol monobutyl ether and dipropylene glycol monomethyl ether, and esters such as [2,2-butoxy] acetate such as ethyl, (2,2-butoxy) acetate propylenecarbonate, ketones, such as acetophenone, methyl-2-hexanone, 2octanone, 4-hydroxy-4-methyl-2-pentanone and 1-methyl-2-pyrrolidone, as such or mixed in an amount of 10 to 90% by weight , preferably in an amount of 15 to 85% by weight, based on the total amount of medium.

10.

Engraving medium according to claim 1 or 2, characterized in that as a thickening agent it contains polymers based on functionalized acrylate or vinyl units and, where appropriate, cellulose / cellulose derivatives or starch / starch derivatives and in an amount of 0.5 to 25% by weight, preferably 3 to 20% by weight, based on the total amount.

eleven.

Engraving medium according to claim 1 or 2, characterized in that it contains from 0 to 5% by weight, based on the total amount, of additives selected from the group of defoamers, thixotropic agents, flow control agents, deaerators and adhesion promoters.

12.

Use of an engraving medium according to claims 1 to 10 in an engraving process in which it is applied on the surface to be etched and removed after an actuation time of 1 to 15 min.

13.

Use of an engraving medium according to claims 1 to 10 in screen printing, clichés, pad printing, printing, inkjet and manual printing processes.

14.

Use of an etching medium according to claims 1 to 10 in photovoltaic, semiconductor technique, high performance electronics, as well as for the manufacture of photodiodes and for the manufacture of glass supports for solar cells or for thermal collectors.

fifteen.

Use of an etching medium according to claims 1 to 10 for the etching of homogeneous, solid, porous or non-porous glasses, based on silicon oxide or nitride systems, as well as layers of varying thickness of said systems.

16.

Use of an etching medium according to claims 1 to 10 for the removal of layers of silicon oxide, doped silicon oxide and silicon nitride or for the selective opening of passivation layers of silicon oxide and nitride of silicon for the production of selective dual stage emitters and / or p + - Local Back-Surface-Fields.

17.

Use of an etching medium according to claims 1 to 10 for full-surface etching and / or structuring of layers of glass and other systems based on silicon oxide, as well as on silicon nitride of varying thickness

in the process of manufacturing components for high performance electronics or in the manufacturing process of semiconductors and their circuits or for the selective opening of passivation layers of silicon oxide and silicon nitride for the production of selective dual level emitters and / or p + - Local Back-Surface-Fields or for engraving edges of solar cell plates coated with silicon oxide and silicon nitride.

18.

Use of an engraving medium according to claims 1 to 10 for microstructural tests.

19.

Procedure for the engraving of crystalline inorganic surfaces of glass type, characterized in that the engraving medium according to claims 1 to 10 is applied over the entire surface or according to the pattern of engraving structure directly only in the places where it is You want an engraving and after the engraving is washed with a solvent or solvent mixture.

twenty.

Method according to claim 19, characterized in that the etching medium is removed by washing with water after engraving.