CN-121989168-A - Method for manufacturing synthetic quartz glass substrate

Abstract

The invention provides a method for manufacturing a synthetic quartz glass substrate, which comprises an evaluation step of evaluating the depth of a processing damage layer in the processing surface of the synthetic quartz glass substrate, and a removal step of removing the processing damage layer based on the evaluation result of the depth of the processing damage layer. The machining damage layer is removed based on evaluating the depth of the machining damage layer in the machining surface. The processing damage layer can be removed reliably and effectively and the productivity of the synthetic quartz glass substrate can be improved.

Inventors

• Ando Masashiro

Assignees

• 信越化学工业株式会社

Dates

Publication Date

20260508

Application Date

20251104

Priority Date

20241105

Claims (7)

1. 1. A method for manufacturing a synthetic quartz glass substrate includes an evaluation step of evaluating the depth of a processing damage layer in a processing surface of the synthetic quartz glass substrate, and a removal step of removing the processing damage layer based on the evaluation result of the depth of the processing damage layer.
2. 2. The method for manufacturing a synthetic quartz glass substrate according to claim 1, wherein in the evaluating step, it is evaluated whether the synthetic quartz glass substrate has predetermined values of arithmetic mean height (Sa), skewness (Ssk) and kurtosis (Sku) in the processed surface, and the removing step is performed according to the evaluation result.
3. 3. The method for manufacturing a synthetic quartz glass substrate according to claim 2, wherein in the evaluating step, a synthetic quartz glass substrate satisfying a predetermined value is selected, and the removing step is performed under a predetermined condition set in advance for the synthetic quartz glass substrate satisfying the predetermined value.
4. 4. The method for manufacturing a synthetic quartz glass substrate according to claim 2 or 3, wherein the predetermined values of the arithmetic mean height (Sa), the absolute value of the skewness (Ssk), and the kurtosis (Sku) are 2.0 μm or less, 0.8 or less, and 5.0 or less, respectively.
5. 5. The method for manufacturing a synthetic quartz glass substrate according to claim 4, wherein the removing step is performed with a removal depth set to 30 μm for the synthetic quartz glass substrate satisfying a predetermined value.
6. 6. The method for manufacturing a synthetic quartz glass substrate according to claim 1, wherein the removing step comprises mirror polishing or wet etching.
7. 7. The method for manufacturing a synthetic quartz glass substrate according to claim 1, wherein the depth of the processing damaged layer is 30 μm or less.

Description

Method for manufacturing synthetic quartz glass substrate Technical Field The present invention relates to a method for manufacturing a synthetic quartz glass substrate. Background Synthetic quartz glass substrates used for semiconductor substrates, optical components, microfluidics, microlens arrays, and the like are subjected to cutting processing to form through holes or non-through holes, grooves, steps, and the like, for practical use. When such a cutting process is performed, a tool such as a grindstone or a drill is often used. Here, a processing damage layer is generated on the processing surface. In order to remove the processing damaged layer, it is necessary to make the amount of grinding, the amount of polishing, and the like larger in the subsequent grinding step, polishing step, and the like, which causes a decrease in productivity. A typical fixed abrasive grain tool for such cutting operations is dressed prior to the start of the cutting operation or during the operation to adjust the protrusion of the abrasive grain or to form the cutting edge of the abrasive grain. Since the state of the tool after dressing is not always constant, a deep processing damaged layer may be abnormally generated or the processing damaged layer depth may be greatly changed depending on the lifetime of the fixed abrasive grain tool. In order to solve such a problem, for example, JP-a 2012-035330 (patent document 1) discloses a method in which, in the production of a glass substrate for a magnetic recording medium, the grain size distribution width of abrasive grains contained in a grindstone is set to be equal to or smaller than a predetermined value so as to suppress the generation of a deep processing damage layer in a processing surface. JP-a 2012-027976 (patent document 2) discloses a method in which, in the manufacture of a glass substrate of a magnetic recording medium, the surface roughness of a cutting surface of a fixed abrasive grain tool is defined to suppress the generation of a deep processing damaged layer in a processing surface. List of references Patent document 1 JP-A2012-035330 Patent document 2 JP-A2012-027976 Disclosure of Invention However, in the method described in patent document 1 or 2, a deep processing damaged layer or a depth variation of the processing damaged layer that is abnormally generated due to the dressing conditions and the lifetime of the grindstone and the fixed abrasive grain tool is not considered. Deep cracks and the like may exist even after the process damaged layer removal step. Measurement of the depth of the process damage layer requires additional steps of precision cleaning, etching, etc., which may deteriorate productivity. The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a manufacturing method capable of reliably and effectively removing a processing damage layer and manufacturing a synthetic quartz glass substrate with good productivity. The present inventors have conducted a great deal of research and, as a result, have found that by evaluating the depth of a processing damaged layer in a processing surface of a synthetic quartz glass substrate and removing the processing damaged layer based on the evaluation result, the processing damaged layer can be reliably and effectively removed and the productivity of the synthetic quartz glass substrate can be improved, leading to completion of the present invention. Accordingly, the present invention provides a method for producing a synthetic quartz glass substrate as follows. 1. A method for manufacturing a synthetic quartz glass substrate includes an evaluation step of evaluating the depth of a processing damage layer in a processing surface of the synthetic quartz glass substrate, and a removal step of removing the processing damage layer based on the evaluation result of the depth of the processing damage layer. 2. The method for manufacturing a synthetic quartz glass substrate according to 1, wherein in the evaluation step, it is evaluated whether the synthetic quartz glass substrate has predetermined values of arithmetic mean height (Sa), skewness (Ssk), and kurtosis (Sku) in the processed surface, and the removal step is performed according to the evaluation result. 3. The method for manufacturing a synthetic quartz glass substrate according to 2, wherein in the evaluation step, a synthetic quartz glass substrate satisfying a predetermined value is selected, and the removal step is performed under a predetermined condition set in advance for the synthetic quartz glass substrate satisfying the predetermined value. 4. The method for manufacturing a synthetic quartz glass substrate according to 2 or 3, wherein the predetermined values of the arithmetic mean height (Sa), the absolute value of the skewness (Ssk), and the kurtosis (Sku) are 2.0 μm or less, 0.8 or less, and 5.0 or less, respectively. 5. The method for manufacturing