JP4059285B2 - Method for processing amorphous material - Google Patents

Description

  The present invention relates to a method for processing an amorphous material such as an inorganic glass material.

  Glass as an amorphous material has been used in a wide variety of fields since it has high hardness and uniform physical properties, and is inexpensive and excellent in economic efficiency.

  In other words, the glass substrate having minute protrusions formed on the surface plays a role in determining the gap length of the so-called cell gap in the liquid crystal display element, and without using glass beads for adjusting the cell gap. A liquid crystal display element having a cell gap can be manufactured.

  In addition, the glass substrate is an important part in manufacturing an optical diffraction grating having regularly arranged protrusions.

  Glass is a brittle material, and shape processing is extremely difficult compared to plastic materials, but various methods for forming minute irregularities on the surface of a glass substrate have been developed and put into practical use.

  For example, Japanese Patent Application Laid-Open No. 64-42025 discloses a technique in which fine irregularities are formed on a glass substrate by performing etching using a chemical solution containing fluorine or hydrogen fluoride gas ( First prior art).

  In JP-A-7-296380, a glass substrate is crystallized, its surface is mirror-polished, and then treated with an etching solution in which sulfuric acid or ammonium fluoride is added to hydrofluoric acid, and the surface of the glass substrate is finely processed. A technique for forming a rough surface has been disclosed (second prior art).

  Further, in JP-A-8-249654, ultrafine particles are applied to a substrate in a monodispersed state, and then the surface protective layer is etched by dry etching, and then the ultrafine particles are removed to form fine particles on the substrate surface. A technique for forming irregularities is disclosed (third conventional technique).

Further, in Japanese Patent Application Laid-Open Nos. 7-182655 and 9-194229, a laser beam having a predetermined energy is irradiated onto the surface of the glass substrate to raise the laser irradiation site, thereby providing a protrusion on the surface of the glass substrate. The formed technology is disclosed (fourth prior art).
JP-A 64-42025 JP 7-296380 A JP-A-8-249654 JP-A-7-182655 JP-A-9-194229

  However, in the first prior art, since the glass having a predetermined chemical composition is only etched using a chemical solution containing fluorine or hydrogen fluoride gas, the surface irregularities formed are Has a problem that it is difficult to obtain a texture having a uniform protrusion height because the protrusion height is irregular and rough.

  Further, the second prior art uses a fact that a glass substrate is crystallized to form a crystallized layer and an amorphous layer, and the etching rate is different between the crystal layer and the amorphous layer. There is a problem that the surface irregularities are formed on the surface, and thus cannot be applied to a normal homogeneous glass material.

  Furthermore, in the third prior art, ultrafine particles are deposited on the substrate, dry etching is performed, and then the ultrafine particles are removed, so that the etching process is performed by masking with a normal metallic mask. In contrast to this, it is considered possible to form minute surface irregularities, but dry etching has a slow etching rate, leading to an increase in cost and unsuitable for mass production.

  In addition, the fourth conventional technique has a problem that the object to be processed is limited to a glass material having a large extinction coefficient with respect to laser light of a specific wavelength because the surface of the glass substrate is irradiated with laser. . In the fourth prior art, the projection height of the projections to be formed is extremely sensitive to the output of the laser beam, and it is difficult to obtain a uniform projection having the desired projection height. There was a problem.

  As described above, the first to fourth prior arts have a problem in that it is impossible to industrially mass-produce minute irregularities having a uniform protrusion height, particularly minute irregularities. Moreover, in recent years, there has been a demand for the height of the projections on the surface irregularities of the glass substrate to be as low as possible and the uniformity of the projection height.

  The present invention has been made in view of such circumstances, and provides an amorphous material processing method capable of forming a surface protrusion having a uniform protrusion height at a desired position of an amorphous material. The purpose is to do.

  As a result of intensive studies to form minute protrusions having a uniform protrusion height at a desired position of the amorphous material, the present inventors have applied amorphous material such as inorganic glass at a high pressure even at room temperature. It was found that the compressed flow is densified by pressing to increase the density, and that the compressed layer and the non-compressed layer other than the compressed layer have different chemical characteristics.

  And when the present inventors further researched, the removal treatment of the surface layer surface of the amorphous material was performed using a treatment agent having different removal ability between the compression layer and the non-compression layer other than the compression layer. As a result, it was found that the compressed layer can be processed into a convex shape.

  The present invention has been made on the basis of these findings, and the method for processing an amorphous material according to the present invention is characterized in that fine particles having a hardness larger than the hardness of the amorphous material are applied to the surface of the amorphous material. To form a densified compressed layer, and then using a processing agent having different removal capability between the compressed layer and the non-compressed layer other than the compressed layer, the amorphous material The surface layer is removed and the compressed layer is processed into a convex shape. Further, the amorphous material is specifically inorganic glass, and the fine particles are in a slurry form. Further, the treating agent having different removal capability is characterized in that the etching solution has different etching rates between the densified compressed layer and the non-compressed layer other than the compressed layer.

  Moreover, it is preferable to use the acidic solution containing the acid which can exhibit a big etching effect | action with respect to inorganic glass as an etching liquid, especially the acidic etching liquid containing hydrofluoric acid.

  By the way, when an etching process is performed with an acidic etching solution, a part of the components constituting the inorganic glass is eluted into the acidic etching solution, and an altered layer is formed on the surface of the non-compressed layer. As a result of research by the present inventors, it has been found that the altered layer can be removed by performing an etching treatment with an alkaline etching solution.

  Therefore, the amorphous material processing method of the present invention is characterized in that after the first etching process is performed with the acidic etching solution, the second etching process is performed with an alkaline etching solution.

  After the first etching process is performed in this manner, the altered layer can be removed by performing the second etching process with an alkaline etching solution, so that the same quality can be maintained on the glass surface and the glass interior. In addition, since the projection height of the surface convex portion is increased, an amorphous material suitable for applications requiring a high projection height can be obtained.

  In addition, inorganic glass, which is an amorphous material, contains silicon oxide as a main component. However, when the inorganic glass contains aluminum oxide, the aluminum oxide is likely to be eluted into an acidic solution. The etching process is accelerated by the acidic etching solution. Moreover, aluminum oxide has excellent corrosion resistance against chemicals other than acids. Therefore, in the densified compressed layer, the densified silicon oxide prevents the elution of other components, while in the non-compressed layer, the aluminum oxide is selectively etched with an acidic etchant, resulting in an inorganic glass surface. A micro-projection is easily formed on the.

  Therefore, it is preferable that the amorphous material contains at least silicon oxide and aluminum oxide.

  Alkaline earth metal oxides are easily eluted in an alkaline solution containing a chelating agent and are excellent in water resistance. Therefore, when the alkaline earth metal oxide is contained in the amorphous material, the alkaline earth metal oxide is selectively etched by the alkaline etchant containing the chelating agent, and the etching process by the alkaline etchant is performed. It becomes possible to form a minute convex part on the glass surface only by itself.

  Therefore, the present invention is characterized in that the etching solution is an alkaline solution containing a chelating agent, and the amorphous material is selected from the group consisting of at least silicon oxide and alkaline earth metal oxide. It is also preferable to contain at least one kind of oxide.

  In order to form a compression layer on the surface of the amorphous material, it is necessary to press the amorphous material with a member having a hardness greater than that of the amorphous material.

  Therefore, in the present invention, the compression layer collides fine particles having a hardness larger than that of the amorphous material with the surface of the amorphous material. Thus, it is also preferable to form a large amount of surface protrusions at a time.

  The fine particles are characterized by being in a slurry form from the viewpoint of avoiding surface damage of the amorphous material.

  In addition, a depression is formed at the top of the compressed layer. Therefore, after forming the compressed layer and before removing the surface layer, if necessary, the compressed layer is polished with free abrasive grains having a hardness equal to or less than the hardness of the amorphous material, The part may be removed.

  The loose abrasive is preferably, for example, colloidal silica.

  In addition, the glass substrate according to the present invention is characterized in that the amorphous material is composed of multi-component inorganic glass, and the convex portion is formed by the processing method of the amorphous material.

  The amorphous material obtained by the above processing method can distribute a large number of uniform and fine protrusions with a high protrusion height and an arbitrary pattern, for example, concentrically.

  As described above in detail, according to the method for processing an amorphous material according to the present invention, fine particles having a hardness larger than the hardness of the amorphous material are partially applied to the surface of the amorphous material. Forming a compressed layer having a high density by colliding with the surface of the material, and then using a treatment agent having a different etching rate between the compressed layer and the non-compressed layer other than the compressed layer. Since the surface layer of the amorphous material is removed and the compressed layer is processed into a convex shape, minute convex portions having a uniform projection height can be formed in an arbitrary pattern.

  In this way, a large number of compressed layers 4 can be obtained at one time.

  Furthermore, surface damage of the amorphous material can be avoided by using the fine particles as a slurry.

  Moreover, the etching process of an incompressible layer can be accelerated | stimulated efficiently by using the acidic solution containing an acid as said etching liquid, especially the acidic etching liquid containing a hydrofluoric acid.

  In addition, since the second etching process is performed with the alkaline etching liquid after the first etching process with the acidic etching liquid, the altered layer formed on the surface of the non-compressed layer after the first etching process is an alkaline solution. The glass surface can be made homogeneous with the glass interior.

  In addition, since the amorphous material contains at least silicon oxide and aluminum oxide, the densified silicon oxide prevents elution of other components in the densified compressed layer, In the compression layer, aluminum having low acid resistance is preferentially etched, and as a result, a desired minute convex portion can be formed quickly and easily.

  Further, since the alkaline earth metal oxide is easily eluted with respect to the alkaline solution containing the chelating agent, the amorphous material is at least one selected from at least silicon oxide and alkaline earth metal oxide. In the case of using an alkaline etching solution containing a chelating agent, the etching is accelerated by the alkaline etching solution, so that even the etching action of the alkaline etching solution alone causes minute irregularities on the surface of the amorphous material. Can be formed.

  Next, an embodiment of the present invention will be described in detail.

The amorphous material used in the present invention is an inorganic glass in consideration of etching properties with respect to an acidic solution and an alkaline solution, and the composition range thereof is SiO ₂ : 55 mol% to 72 mol%, Al ₂ O ₃ : 1 mol% to 12 0.5 mol%, alkaline earth metal oxides (MgO, CaO, SrO and BaO): 2 mol% to 16 mol% in total, Li ₂ O: 5 mol% to 20 mol%, Na ₂ O: 12 mol% or less.

  The reason for the limitation will be described below.

SiO ₂ is a main component constituting the inorganic glass. When the content is less than 55 mol%, the durability of the glass is deteriorated. On the other hand, when it exceeds 72 mol%, the viscosity increases so that melting becomes difficult. Therefore, in this embodiment, the content of SiO ₂ is set to 55 mol% to 72 mol%.

Al ₂ O ₃ is a component that improves the durability of the glass and is a component that is easily eluted with respect to the acidic etching solution. However, if the content is less than 1 mol%, the desired effect cannot be achieved. On the other hand, if the content exceeds 12.5 mol%, the viscosity increases too much, devitrification resistance decreases, and melting is difficult. become. Therefore, in the present embodiment, the content of Al ₂ O ₃ is set to 1 mol% to 12.5 mol%.

  MgO, CaO, SrO, BaO, etc. are alkaline earth metal oxides. Such alkaline earth metal oxides increase the meltability of inorganic glass and are easy to elute into an alkaline solution containing a chelating agent. Therefore, the etching process is accelerated with respect to the alkaline etching solution. However, if the content is 2 mol% or less, the desired effect cannot be achieved. On the other hand, if the content exceeds 16 mol%, the liquidus temperature of the glass increases and the devitrification resistance deteriorates. Therefore, in this embodiment, the total content of MgO, CaO, SrO, and BaO, which are alkaline earth metal oxides, is set to 2 mol% to 16 mol%.

Li ₂ O is a component that enhances the meltability at the time of melting the glass. If the content is less than 5 mol%, the viscosity increases and melting becomes difficult. On the other hand, if the content exceeds 20 mol%, Durability is deteriorated. Therefore, in the present embodiment, the content of Li ₂ O is set to 5 mol% to 20 mol%.

Na ₂ O is also a component that enhances the meltability at the time of melting the glass, but if its content exceeds 12 mol%, the chemical durability deteriorates. Therefore, in this embodiment it was set content of Na ₂ O below 12 mol%.

Note that these Li ₂ O, by the inclusion of alkali metal oxides Na ₂ O or the like in the inorganic glass 1, it is possible to chemically strengthened by ion exchange.

Furthermore, the inorganic glass can appropriately contain colorants such as Fe ₂ O ₃ , MnO, NiO, Cr ₂ O ₃ , and CoO as long as the various properties required by the present invention are not impaired.

In addition to the non-machine glass as described above, for example, inorganic with or inorganic glass containing B ₂ O ₃ in addition to Al ₂ O _3, the alkali-free glass, a component for controlling the refractive index for optical applications The present invention is also effective for glass.

  Next, as shown in FIG. 1 (a), by forming fine particles having a hardness larger than the hardness of the amorphous material on the surface of the inorganic glass 1 to form a recess 3 on the surface of the inorganic glass 1. The compression layer 4 having is formed.

  Examples of the method for causing the fine particles to collide include an air blast method in which fine particles are sprayed onto the inorganic glass 1 using air as a medium, and a wet blast method in which fine particles made into a slurry form using a liquid such as water as a medium are sprayed onto the inorganic glass 1. . In particular, since the latter uses a liquid as a medium, it can be made to collide with the surface of the inorganic glass 1 without agglomerating individual fine particles, and since the injection speed is easy to control, scratches and cracks due to overpressure are hardly generated. Since the compression layer 4 can be uniformly formed on the surface of the inorganic glass 1, it is more preferable as a method for forming the compression layer 4.

Next, the inorganic glass 1 on which the compression layer 4 is formed is immersed in an acidic etching solution and a first etching process is performed to remove the surface layer of the inorganic glass 1, and as shown in FIG. The minute projections 5 are formed in the compressed layer 4 portion, and components other than SiO ₂ are eluted from the non-compressed layer 6 other than the compressed layer 4 to form the altered layer 7.

That is, the composition of the inorganic glass 1 includes a component having strong acid resistance and a component having weak acid resistance. Specifically, SiO ₂ has strong acid resistance, and Al ₂ O ₃ , alkali metal oxides (Li ₂ O and Na ₂ O), and alkaline earth metal oxides (MgO, CaO, SrO, BaO, etc.) are acid. It has the characteristic that it is easily eroded.

Accordingly, the dense compressed layer 4 is difficult to be etched by the acidic etchant because the densified SiO ₂ prevents elution of other components, while the non-compressed layer 6 is composed of an acidic etchant other than the SiO ₂ component. To selectively etch. As a result, etching is accelerated in the non-compressed layer 6, and the compressed layer 4 remains as a minute convex portion 5.

Furthermore, as described above, the non-compressed layer 6 selectively etches components other than the SiO ₂ component with the acidic etching solution. As a result, components other than SiO ₂ are eluted, and the surface of the non-compressed layer 6 is porous. A quality altered layer 7 is formed.

  As the acidic etching solution, an aqueous solution of sulfuric acid, nitric acid, hydrochloric acid, fluoroacetic acid or the like can be used, but an aqueous solution of a strong acid is desirable in order to perform a desired etching process quickly, and the concentration is particularly high. An aqueous solution containing 0.005 vol% or more hydrofluoric acid is most preferable because of its excellent etching action.

Next, a second etching process is performed by immersion in an alkaline etching solution, and the altered layer 7 is removed as shown in FIG. That is, the altered layer 7 is a chemically unstable porous portion, and is a portion in which components other than SiO ₂ are eluted from the surface of the inorganic glass 1. As with the glass interior, the structure is chemically stable.

  As the alkaline etching solution, for example, an aqueous potassium hydroxide solution having a pH of 11 or more, or a diluted solution of a commercially available alkaline cleaning solution can be used.

  In addition, the alkaline earth metal oxide is easily eluted into an alkaline solution containing a chelating agent, and it is also preferable to perform the second etching treatment with an alkaline etching solution containing a chelating agent from this viewpoint.

  Here, as the chelating agent, aminocarboxylic acids such as EDTA (ethylenediaminetetraacetic acid) and NTA (nitrilotriacetic acid), polyvalent carboxylic acids such as oxalic acid, and phosphates such as STPP (sodium tripolyphosphate) are used. be able to.

  As described above, according to the first embodiment, the compressed layer 4 is formed, and the compressed layer 4 is formed on the portion where the compressed layer 4 is formed using the difference in etching property between the compressed layer 4 and the non-compressed layer 6. 5 is formed, it is possible to form the minute projections 5 having a uniform protrusion height on the surface of the inorganic glass 1 in an arbitrary pattern.

  Further, when the compression layer 4 is formed, as shown in FIG. 1 (a), the depression 3 is formed. Therefore, when the etching process is performed with the depression 3 remaining, a minute projection is formed. The shape of 5 may be substantially V-shaped or caldera-shaped as shown in FIG. Therefore, depending on the use of the inorganic glass 1, the surface treatment may be performed to remove the recess 3, and then the etching treatment may be performed.

  Here, as the surface treatment, it is necessary to prevent the inorganic glass 1 from being scratched. Therefore, polishing is performed using free abrasive grains having a hardness equal to or lower than the hardness of the inorganic glass 1. The free abrasive grains are preferably spherical, and for example, colloidal silica can be used.

  Further, as described above, since alkaline earth metals are easily eluted with respect to an alkaline solution containing a chelating agent, compounds containing alkaline earth metals, that is, MgO, CaO, SrO, BaO, etc. Therefore, when the protrusion height may be small, only etching with an alkaline solution is possible, that is, etching using an acidic etching solution can be omitted.

  Next, examples of the present invention will be specifically described.

  Table 1 is a list of compositions of the inorganic glass 1 used in this example, and the inventors used the inorganic glass 1 of any one of the compositions 1 to 4 shown in Table 1 and used the following test pieces. (Examples 1 to 4 and Comparative Examples 1 and 2) were prepared, and the state of the surface protrusions (bottom diameter and protrusion height) was observed.

[Example 1]
After using the inorganic glass 1 of the composition 1 and polishing it to improve the smoothness of the surface of the inorganic glass 1, the particle size is 20 μm using compressed air of 9.8 × 10 ⁴ Pa (1 kg / cm ² ). The zirconia particles were sprayed for 20 seconds, thereby forming a large number of compressed layers 4 having depressions 3. After that, 200 nm polishing was performed using a slurry mixed with colloidal silica, and the depression 3 was removed. Next, the inorganic glass 1 from which the hollow portion 3 has been removed is immersed in a hydrofluoric acid solution having a concentration of 0.025 vol% and etched, and then immersed in an alkaline etching solution having a pH of 12 to remove the altered layer 7. 1 test piece was produced.

Then, when the surface shape of the test piece was observed with an AFM (atomic force microscope), 50 fine protrusions 5 were formed on the surface of the test piece per 10 μm ² , and the bottom surface had a diameter of 4 μm. It was a substantially circular chevron shape, and the projection height was 100 nm ± 10 nm.

[Example 2]
While a slurry containing 17 vol% of an alumina abrasive with a particle size of 5 μm was blown out in a mist form from a 90 × 2.0 mm nozzle with compressed air of 0.05 MPa, the nozzle was blown at a speed of 25 mm / sec. The surface of the glass 1 was scanned and sprayed to form a large number of compressed layers 4 having depressions 3. Thereafter, the slurry was mixed with cerium powder and polished for 60 nm to remove the recess 3. Next, the inorganic glass 1 from which the depressions 3 have been removed is etched by immersing it in a hydrofluoric acid aqueous solution having a concentration of 0.10 vol%, and then immersed in an alkaline etching solution having a pH of 12 to remove the altered layer 7. A test piece was prepared.

Then, when the surface shape of the test piece was observed with AFM, 84 fine convex portions 5 were formed on the surface of the test piece per 10 μm ² , and the shape was a substantially circular chevron shape with a bottom surface of 570 nm in diameter. The protrusion height was 130 ± 5 nm. Moreover, in this method, since the compression layer 4 was formed by the wet blast method, it was possible to form protrusions having a uniform height without generating cracks.

Example 3
The same treatment as in Example 2 was performed on the surface of the inorganic glass 1 having the composition 2 to prepare a test piece of Example 3.

When the surface shape of the test piece was observed with an AFM, 49 fine protrusions 5 were formed on the surface of the test piece per 10 μm ² , and the shape was a substantially circular chevron shape with a bottom surface of 460 nm in diameter. there were. The height of the protrusion was 120 ± 5 nm, and a uniform minute convex portion 5 having a small variation in the height of the protrusion was formed. Thus, in the inorganic glass 1 having a composition containing B ₂ O _{3 in} addition to Al ₂ O ₃ , the minute protrusions 5 could be formed on the surface.

Example 4
The same treatment as in Example 2 was performed on the surface of the inorganic glass 1 having the composition 3 to prepare a test piece of Example 4.

Then, when the surface shape of the test piece was observed with an AFM, eleven minute convex portions 5 were formed on the surface of the test piece per 10 μm ² , and the shape was a substantially circular chevron shape with a bottom surface of 330 nm in diameter. there were. The height of the protrusion was 100 ± 5 nm, and a uniform minute convex portion 5 having a small variation in the height of the protrusion was formed. Thus, similarly to Example 10, in the inorganic glass 1 having a composition containing B ₂ O _{3 in} addition to Al ₂ O ₃ , the minute protrusions 5 could be formed on the surface.

[Comparative Example 1]
After using the inorganic glass 1 of composition 4 and polishing to improve the smoothness of the surface of the inorganic glass 1, the inorganic glass 1 is 6: 4 in a volume ratio of potassium nitrate and sodium nitrate at a temperature of 380 ° C. In the molten salt prepared for 1 hour, a chemical strengthening treatment is performed to form the compressed layer 4, and then the inorganic glass 1 is irradiated with laser light having a wavelength of 266 nm, an output of 10 mW, and a pulse width of 5 nsec. A test piece was prepared.

  Then, when the surface shape of the test piece was observed with an AFM (Atomic Force Microscope), the surface of the test piece was raised to form a large number of minute convex portions 5, and the shape of the test piece was substantially circular with a bottom surface having a diameter of 5 μm. The protrusion height was 30 nm ± 15 nm. That is, in Comparative Example 1, it was found that the protrusion height of the minute convex portion 5 is 30 nm ± 15 nm, and the variation degree is larger than that in Example 1.

[Comparative Example 2]
The inorganic glass 1 having the composition 1 was used and polished to improve the smoothness of the surface of the inorganic glass 1, and then held at a temperature of 460 ° C. for 2 hours to remove distortion caused by polishing. Next, an indenter 2 made of diamond formed in a quadrangular pyramid shape with an apex angle of 136 ° is pressed against the surface of the inorganic glass 1 with a load of 500 g (4.2 GPa) for 15 seconds, thereby forming a compressed layer 4 having a depression 3. did. After that, polishing was performed with a thickness of 500 nm using a slurry mixed with colloidal silica, and the depression 3 was removed. Next, the inorganic glass 1 from which the recess 3 has been removed is immersed in a 0.15 vol% hydrofluoric acid aqueous solution for etching, and then immersed in an alkaline etching solution having a pH of 12 to remove the altered layer 7. Comparative Example 2 A test piece was prepared.

  Then, when the surface shape of the test piece was observed with an AFM (atomic force microscope), a minute convex portion 5 was formed on the surface of the test piece, and the shape thereof was a substantially square caldera shape with a bottom surface of 40 μm on a side. Thus, the protrusion height of the outer ring crest portion was 700 nm, had a flat region at the top, and cracks occurred around the minute convex portion 5.

  That is, in Comparative Example 2, since the compression layer 4 was formed by applying a large load of 4.2 GPa to the inorganic glass, cracks occurred around the minute protrusions 5.

It is explanatory drawing of the manufacturing process which shows the form of the processing method of the amorphous material which concerns on this invention.

Explanation of symbols

1 Inorganic glass (amorphous material)
3 Depression 4 Compressed layer 6 Uncompressed layer 7 Altered layer

Claims (12)

Fine particles having a hardness greater than the hardness of the inorganic glass are partially collided with the surface of the inorganic glass to form a densified compressed layer,
Next, the surface layer of the inorganic glass is removed using etching solutions having different etching rates between the compressed layer and the non-compressed layer other than the compressed layer, and the compressed layer is processed into a convex shape. A processing method of an amorphous material.   2. The method for processing an amorphous material according to claim 1, wherein the fine particles are caused to collide with the surface of the amorphous material by blowing air as a medium.   2. The method for processing an amorphous material according to claim 1, wherein the fine particles are caused to collide with the surface of the amorphous material by spraying in a slurry form using a liquid as a medium. The etchant is a processing method of the amorphous material according to claim 1, characterized in that the acidic solution containing an acid.   The method for processing an amorphous material according to claim 4, wherein the acidic solution contains hydrofluoric acid. Fine particles having a hardness greater than the hardness of the inorganic glass are partially collided with the surface of the inorganic glass to form a densified compressed layer,
Next, an amorphous material that removes the surface layer of the inorganic glass and processes the compressed layer into a convex shape using etching solutions having different etching rates between the compressed layer and the non-compressed layer other than the compressed layer. A processing method,
The etchant is an acidic solution, after the first etching process in the acidic solution, the processing method of the amorphous material, characterized in that a second etching process is performed in an alkaline solution. The method for processing an amorphous material according to claim 6 , wherein the alkaline solution contains a chelating agent. The inorganic glass includes at least silicon oxide, the processing method of the amorphous material according to claim 1, characterized by containing an aluminum oxide. The method for processing an amorphous material according to claim 8 , wherein the inorganic glass contains at least silicon oxide and at least one alkaline earth oxide. 10. The method for processing an amorphous material according to claim 9, wherein the alkaline earth metal oxide contains at least one selected from MgO, CaO, SrO and BaO. Fine particles having a hardness greater than the hardness of the inorganic glass are partially collided with the surface of the inorganic glass to form a densified compressed layer,
  Next, an amorphous material that removes the surface layer of the inorganic glass and processes the compressed layer into a convex shape using etching solutions having different etching rates between the compressed layer and the non-compressed layer other than the compressed layer. A processing method,
  After the compression layer is formed, the compression layer is polished with free abrasive grains having a hardness equal to or lower than the hardness of the amorphous material, and then the surface layer is removed using the etching solution. A method for processing an amorphous material. The free abrasive grains, a processing method of an amorphous material according to claim 1 1, wherein it is a colloidal silica.

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