CN117529457A

CN117529457A - Method for manufacturing quartz glass jig and quartz glass jig

Info

Publication number: CN117529457A
Application number: CN202280042598.3A
Authority: CN
Inventors: 藤田大辉; 濑川彻; 丸子洋一郎
Original assignee: Shin Etsu Quartz Products Co Ltd
Current assignee: Shin Etsu Quartz Products Co Ltd
Priority date: 2021-06-25
Filing date: 2022-06-23
Publication date: 2024-02-06
Also published as: WO2022270576A1; KR20240036521A; TW202317496A; JPWO2022270576A1

Abstract

The invention aims to provide a method for manufacturing a quartz glass clamp and a quartz glass clamp, wherein in the formation of concave-convex by liquid medicine treatment without microcrack, even for a large quartz glass clamp, the concave-convex processing surface of the surface is inconspicuous, and the concave-convex processing surface with excellent uniformity is provided. A method for manufacturing a quartz glass jig, which is formed by treating a surface with a chemical solution to form irregularities, comprises: an adhering matter removing step of removing adhering matter on the smooth quartz glass surface; and a processed surface forming chemical solution treatment step of forming a processed surface of the quartz glass surface from which the adhering matter is removed by forming irregularities by the chemical solution treatment, wherein a standard deviation of the processed surface of the irregularities at 10 points is 1.00 μm or less when the surface roughness Ra of the processed surface of the irregularities is measured.

Description

Method for manufacturing quartz glass jig and quartz glass jig

Technical Field

The present invention relates to a method for manufacturing a quartz glass jig in which irregularities free from microcracks are formed on a surface of quartz glass by chemical solution treatment, and a quartz glass jig in which irregularities are formed on a surface.

Background

Quartz glass has been conventionally used as a material for semiconductor processing, optical, physical and chemical equipment, decoration, and the like because of its high purity and excellent chemical resistance. These quartz glass processed products may be roughened by performing various uneven processing on the surfaces thereof according to the purpose of use. In particular, by providing irregularities on the inner surface of a furnace tube used in semiconductor manufacturing, film formation peeling of a polysilicon film or the like during LPCVD (Low Pressure Chemical Vapor Deposition) processing is prevented, and particles generated during heat treatment of a wafer are prevented.

As a method for performing the concave-convex processing on the surface of the quartz glass, shot blasting and HF/CH processing are known ₃ COOH/NH ₄ Surface treatment is performed by the mixed solution (surface treatment solution) of F. Since the shot blasting is a machining method involving mechanical damage to the surface, the presence of microcracks on the quartz glass surface causes generation of particles and the like, and is not an effective method. In addition, in the surface roughness processing of the surface treatment by the surface treatment liquid, since the microcracks described above are not present, the surface roughness processing is suitable for use in the semiconductor process, and has been used for a long time. As examples of the surface treatment liquid for imparting irregularities to the surface of quartz glass, patent documents 1 to 3, for example, are cited. In addition, in the semiconductor process, in order to prevent the polysilicon film and the like from peeling from the quartz glass surface (hereinafter also referred to as "film peeling prevention"), it is generally known that film peeling is difficult to occur when the surface roughness is large.

However, in the surface treatment method of quartz glass by the surface treatment liquid, there is a problem that the surface roughness is not uniform and the control is not easy, compared with the processing method involving mechanical damage by shot blasting. Further, the surface to be treated is immersed in the surface treatment liquid, and thus the white turbidity caused by the formation of irregularities on the surface after completion may be uniform or locally non-uniform. The presence of such uneven portions causes problems such as localized embrittlement of the film adhering to the quartz, peeling of the film, and failure to achieve the intended function. In addition, in the case where uneven irregularities (speckles) are formed, the chemical treatment is repeated in order to eliminate the speckles, but there are cases where the speckles such as large speckles, streaky speckles, and aggregates of small speckles are difficult to eliminate, and multiple chemical treatments are required.

In the specification paragraph 0008 of the japanese patent document 4, a description is given of the streak on the treated surface, and as a countermeasure therefor, a proposal focusing on the reynolds number Re is made. The speckle as discussed herein refers to the shade of the processing surface when the processing surface is viewed from a position of about 1m, and therefore, a predetermined reynolds number or the like for processing a large processing surface under the same conditions functions as a countermeasure.

On the other hand, in film forming processes in recent semiconductor manufacturing processes, more localized "uneven surface" irregularities are emphasized. Such local streaks are somewhat transparent (i.e., extremely small or extremely large surface roughness Ra) areas of about 1cm square, or directional local streaks such as bristle lines or fingerprints of about 1cm square size, which are produced in an opaque uneven surface due to the occurrence of clouding of the surface irregularities. The local streaks having directionality may have a surface roughness level equal to that of the surrounding uneven processed surface or a surface roughness level different from that of the surrounding uneven processed surface. In a quartz glass jig used in a film forming process, films laminated according to the number of film forming times are adhered, but if the film thickness on the quartz glass jig becomes thick due to an extension of a cleaning cycle for improving productivity, fine peeling may occur from the local streak as a starting point during a temperature rising and a temperature lowering before and after the film forming process, which may cause particulate contamination in the process.

In the conventional surface treatments described in patent documents 1 to 4, a small area is targeted, and therefore, if the surface area is small, no unevenness is noticeable even if the unevenness is formed, and therefore, it appears that there is no unevenness (little unevenness).

However, in recent years, with the enlargement of semiconductor wafers, quartz glass jigs have also been enlarged, and in the conventional use of Si wafers having a diameter of 6 inches to 8 inches, irregularities on the surface are inconspicuous, and the increase in the number of Si wafer processing pieces per batch and the 12 inch size of Si wafers have been the main stream, so that the quartz glass jigs have been enlarged, and the furnace tube, the circular seal material, and the top plate of quartz glass have been enlarged and elongated, and the surface area has been enlarged, and therefore, irregularities have been made conspicuous on the surface.

The uneven surface cloudiness caused by the uneven processing unevenness, in detail, the presence of the transparent portion and the opaque portion is caused by the uneven structure of the surface, and therefore, if the uneven processing unevenness is present in the quartz glass jig, the difference in the adhesion effect of the film attached to the wafer during the film forming process is generated as a result, which is not preferable. In addition, if the uneven processing unevenness exists in the quartz glass jig, the uneven processing unevenness is not preferable from the viewpoint of film uniformity in wafer processing because a heat ray transmission difference occurs in the heater during the film forming process, and the temperature distribution is caused.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 10-273339

Patent document 2: WO2004/051724

Patent document 3: japanese patent laid-open No. 2001-335342

Patent document 4: japanese patent laid-open publication No. 2005-145721

Disclosure of Invention

Problems to be solved by the invention

Conventionally, there is a case where alcohol wiping or the like is performed on a processing workpiece placed for a long period of time as a pretreatment of chemical solution treatment, but there is a case where a workpiece subjected to surface flame polishing in a general product manufacturing process has a clean surface, and therefore, the workpiece is cooled in a clean environment and then directly enters a process of forming an uneven surface by chemical solution.

As a result of the studies conducted by the present inventors on the solution of local streaks, it was found that even when the process is performed in a short process, the local streaks are generated due to the adhesion of fingerprints, grease from gloves and the like, the adhesion of water and the like, dust, garbage, and dirt adhering to a plastic cover for avoiding garbage, to the surface of a workpiece, which hinders the reaction in the chemical process.

Therefore, the reaction by the chemical treatment becomes unstable at the portion where the surface to be treated has the adhering matter (adhering moisture and oil), and the uneven surface is formed when the entire quartz glass jig is viewed, because the size of the partially formed uneven surface is different or is not formed. When used in the film forming step, the film may have a portion where a sufficient effect cannot be obtained. Such uneven surfaces may cause uneven and cloudy surfaces, or may cause film peeling at uneven portions.

In the case where the contaminated portion and the content (for example, oil) on the surface are specified, the cleaning can be performed by an organic solvent such as alcohol or acetone, but since detection of thin greasy dirt or the like is difficult to specify, it is most effective to remove at least the outermost substance on the entire workpiece before the chemical treatment is performed, and it is judged that the cleaning is an effective improvement measure.

The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a method for manufacturing a quartz glass jig and a quartz glass jig, which are capable of providing an uneven surface with excellent uniformity, even in a large-sized quartz glass jig, in which irregularities are formed by chemical treatment without microcracks.

Technical means for solving the problems

The method for manufacturing a quartz glass jig according to the present invention is a method for manufacturing a quartz glass jig having irregularities formed on a surface thereof by chemical treatment, comprising: an adhering matter removing step of removing adhering matter on the smooth quartz glass surface; and a processed surface forming chemical treatment step of forming a processed surface of the quartz glass surface from which the adhering matter has been removed by forming irregularities by the chemical treatment, wherein a standard deviation of the processed surface of the irregularities at 10 or more points is 1.00 [ mu ] m or less.

Preferably, the relief work surface has a gloss of less than 2 at 60 degrees gloss meter. Further, it is preferable that the average value of visible light transmittance of the uneven surface obtained by a colorimeter is 30% or less and the standard deviation is 1% or less.

The coefficient of variation in measuring the surface roughness Ra of the uneven machined surface at 10 or more points is preferably 0.60 or less.

Preferably, the adhering matter removing step includes: an HF cleaning step of removing the adhering matter on the surface of the smooth quartz glass by using a cleaning liquid containing HF; a first removal step of diluting and removing HF components remaining on the surface of the quartz glass with water after the HF cleaning step; and a second removal step of removing the adhering moisture and/or adhering solvent remaining on the surface of the silica glass after the first removal step.

Preferably, in the HF cleaning step, the glass surface layer of the quartz glass surface is etched to remove 0.10 μm or more.

Preferably, the second removing step is a drying step of drying the quartz glass surface in a clean environment in which the humidity is less than 60%.

Preferably, the chemical treatment is performed by using a chemical solution containing HF and NH ₄ F and acetic acid.

The quartz glass jig of the present invention is a jig having a surface of at least 20cm on the surface of quartz glass ² Stone with the above-mentioned area formed with concave-convex liquid medicine treatment partAnd an quartz glass jig, wherein the chemical treatment portion is used as an uneven surface on which irregularities are formed, and the standard deviation of the surface roughness Ra of the uneven surface is 1.00 μm or less when 10 or more parts are measured.

Preferably, the relief work surface has a gloss level of less than 2 at 60 degrees. Further, it is preferable that the average value of visible light transmittance of the uneven surface obtained by a colorimeter is 30% or less and the standard deviation is 1% or less.

Preferably, the variation coefficient when measuring the surface roughness Ra of the uneven machined surface of 10 or more points is 0.60 or less.

The quartz glass jig of the present invention can be manufactured by the method for manufacturing a quartz glass jig of the present invention.

Effects of the invention

According to the present invention, a method for manufacturing a quartz glass jig and a quartz glass jig can be provided, which can provide a large-sized quartz glass jig having a surface with irregularities, in which irregularities are not visible even in the case of forming irregularities by chemical treatment without microcracks, and which has an excellent uniformity. That is, according to the present invention, it is possible to provide a method for manufacturing a quartz glass jig, which can reduce unevenness of unevenness forming to be uneven by a chemical treatment, and which has a good appearance, even when the quartz glass jig is large.

Further, by reducing the unevenness of the surface roughness of the silica glass jig, even in the case of a large-sized silica glass jig, the surface state of the silica glass can be made uniform, and the film peeling at the portion where the silica glass is uneven can be prevented.

Further, when the quartz glass jig is used in a semiconductor manufacturing apparatus, the elimination of the cloudiness has an effect of suppressing the temperature distribution with a reduction in the difference in heat ray penetration from the heater in the semiconductor manufacturing process, and also an effect of contributing to uniformity of wafer processing.

Drawings

Fig. 1 is an electron micrograph of the surface of the silica glass jig produced in example 1.

Fig. 2 is an electron micrograph of a portion of the surface of the silica glass jig produced in comparative example 1, which is highly clouded.

Fig. 3 is an electron micrograph of a portion having a thin and transparent surface of the quartz glass jig manufactured in comparative example 1.

Fig. 4a is a schematic explanatory view of measurement points in the measurement method of the surface roughness Ra of the silica glass jig of example 1, as seen from the side surface of the silica glass jig.

Fig. 4b is a schematic explanatory view of a measurement point in the measurement method of the surface roughness Ra of the quartz glass jig of example 1, as seen from the upper end side of the quartz glass jig.

Fig. 5 is a photograph of the appearance of the quartz glass jig manufactured by example 1.

Fig. 6 is a photograph showing the appearance of a quartz glass jig manufactured by performing a chemical treatment 4 times.

Fig. 7 is a photograph of the appearance of the upper surface of the silica glass jig obtained in comparative example 1.

Fig. 8 is a photograph showing the appearance of the side surface of the silica glass jig obtained in comparative example 1, (a) being the whole side surface, and (b) being an enlarged photograph of the main portion of (a).

Fig. 9 is a photograph of the appearance of the lower surface of the silica glass jig obtained in comparative example 1.

Fig. 10 is a photograph of the quartz glass jig obtained in comparative example 2, (a) a photograph of a major portion of the side face, and (b) a photograph of a major portion of the lower surface.

Fig. 11 is a photograph of the quartz glass jig obtained in comparative example 3, (a) a photograph enlarged for a major portion of the upper surface, and (b) a photograph enlarged for a major portion of the lower surface.

Detailed Description

The embodiments of the present invention will be described below, but these embodiments are merely illustrative examples, and various modifications can be made without departing from the scope of the technical idea of the present invention.

The smooth quartz glass surface means a quartz glass surface formed of irregularities without physical or chemical surface treatment.

The quartz glass jig obtained by the method of the present invention has a roughened surface with excellent uniformity, and in the present invention, the surface roughness Ra is calculated according to JISB 0601:2001. Further, it is preferable that the coefficient of variation in measuring the surface roughness Ra of the uneven machined surface of 10 or more points is 0.60 or less. The surface roughness Ra of the uneven surface is preferably 10 to 50 points. The number of measurement sites of the surface roughness Ra is at least 10, and is preferably adjusted by increasing or decreasing the measurement sites according to the size, surface area, and the like of the quartz glass jig so that the surface of the quartz glass jig can be measured without any deviation.

In this way, for the determination of the uniformity/unevenness of the cloudiness (i.e., uniformity/unevenness of the formation of irregularities) of the silica glass jig, it is preferable that the standard deviation when measuring the surface roughness Ra of the surface on which irregularities are formed at 10 or more sites is 1.00 μm or less, and the coefficient of variation when measuring the surface roughness Ra of the surface at 10 or more sites is 0.60 or less.

By improving the uniformity of the uneven surface, a quartz glass jig having a surface which is uniformly clouded and has uniform transparency can be provided.

The degree of cloudiness and transparency of the textured surface is not particularly limited, but a translucent surface that is uniformly cloudy is preferable, and particularly, the textured surface preferably has a gloss of less than 2 at 60 degrees. In the present invention, the measurement of the glossiness can be performed by measuring 60 degrees specular gloss by a known gloss meter according to JIS Z8741-1997 specular gloss-measuring method. The average value of the glossiness when the uneven surface is measured at 10 or more points is preferably less than 2, more preferably 1 or less. The maximum value of the glossiness of the textured surface at 60 degrees is preferably less than 2, more preferably 1 or less.

The average value of the visible light transmittance of the uneven surface obtained by the colorimeter is preferably 30% or less, and the standard deviation of the visible light transmittance is preferably 1% or less, more preferably 0.5% or less. In the present invention, the measurement of the visible light transmittance is performed by using a known tone meter (visible light transmittance measuring device) on 10 or more samples cut from the quartz glass jig, and the thickness of the measurement sample is preferably 1mm to 18mm.

The measurement points of the glossiness and visible light transmittance are preferably selected according to the measurement points of the surface roughness Ra.

The formation of irregularities by the chemical treatment is called a reaction between the chemical component and the quartz glass, and a part of the reaction product is formed as (NH ₄ ) ₂ SiF ₄ The micro-crystallization is precipitated, and the surface is unevenly eroded to form the concave-convex shape according to the difference in etching progress between the portion where the micro-crystallization is precipitated and the portion where the micro-crystallization is not precipitated. That is, basically, the surface to be treated is eroded in the chemical solution to generate irregularities.

Examples of the adhering substance on the surface of the silica glass include adhering oil due to contact with the adhering grease or the like with a finger, adhering water such as adhering water, dust, garbage, and the like.

The adhering matter removing step preferably includes: an HF cleaning step of removing the adhering matter on the surface of the smooth quartz glass by using a cleaning liquid containing HF; a first removal step of removing HF components remaining on the surface of the quartz glass by dilution with water; and a second removal step of removing the adhering moisture and/or adhering solvent remaining on the surface of the silica glass. In this way, the adhering matter (adhering moisture and oil) on the surface of the quartz glass jig is removed by the HF-containing cleaning liquid, and after the removal by the HF cleaning, the quartz glass jig is sufficiently cleaned by water and dried. The drying is preferably a drying step in a clean environment in which the cleanliness is managed, such as a clean dryer or a room in which the cleanliness of the atmosphere is managed. Then, surface treatment is rapidly performed. The rapid surface treatment means that the surface treatment is performed rapidly without performing storage such as temporary storage under a clean atmosphere. Thus, a rough surface having excellent uniformity was formed on the surface of the quartz glass jig, and the cloudiness of the surface of the quartz glass jig by roughening was also homogenized.

The water used in the first removal step also contains pure water. If the water is insufficient to clean the quartz glass, HF components remain, and the quartz glass is immersed in the surface treatment liquid, uneven adhesion is caused by the formation of irregularities. The water used for water washing is preferably pure water, more preferably pure water having a specific resistance value of 15mΩ or more, and even more preferably ultrapure water (having a specific resistance value of 17.5 to 18.2mΩ).

In the HF cleaning step, the glass surface layer of the quartz glass surface is preferably etched to remove 0.10 μm or more. Further, it is more preferable that the glass surface layer of the quartz glass surface is etched to remove 0.10 μm or more and 30.0 μm or less.

The cleaning liquid containing HF is preferably an aqueous solution having an HF concentration of 2 to 25 mass%. The treatment time for the HF cleaning is not particularly limited, but is preferably selected appropriately so that the etching removal of the appropriate amount is performed.

Preferably, the second removing step is a drying step of drying the quartz glass surface in a clean atmosphere having a humidity of less than 60%. Thus, the drying step is preferably performed in an atmosphere having a humidity of less than 60%.

The clean environment is preferably an environment in which the cleanliness (detergency) according to ISO 14644-1 is 7 or less (federal specification class 10,000), more preferably an environment in which the cleanliness is 6 or less (federal specification class 1,000). The drying process in the clean environment may be performed in a clean room in which cleanliness is managed, or may be performed using a clean dryer. In this specification, drying under a clean environment in which cleanliness is managed is referred to as clean drying, and drying under an atmosphere in which cleanliness is not managed is referred to as general drying.

The drying is preferably performed at room temperature of 20 ℃ or higher and in an environment with humidity lower than 60%, and may be performed in a dryer or in a room with a controlled environmental cleanliness. In order to shorten the drying time, a method of directly drying quartz glass using an IR lamp, hot air, or the like may be applied.

In this way, in the method for manufacturing a silica glass jig according to the present invention, the surface of the silica glass may be completely removed from the surface by performing HF cleaning using a cleaning solution of HF, performing water cleaning, drying the surface by using a solvent (such as acetone or alcohol) to remove and dry the residual water, and immersing the surface in a surface treatment solution. When a solvent (acetone, alcohol, etc.) is used, the coating may be performed by wiping with a dust-free cloth or by spraying.

The oil component of the deposit is the oil component adhering to the glass surface, but the oil component may be removed by applying a cleaning liquid of HF, sufficiently washing with water, removing the oil component with a solvent (such as acetone or alcohol), and drying the oil component, or may be immersed in a surface treatment liquid after irradiation with a UV lamp.

As the moisture and oil components as the attached matter, organic substances (for example, hydrocarbon compounds) may be mentioned as the attached matter. Even such organic substances can be removed simultaneously by the above-described steps.

As the treatment liquid used for the chemical treatment, a conventionally used treatment liquid can be used, and specifically, a treatment liquid containing Hydrogen Fluoride (HF) and ammonium fluoride (NH) ₄ F) Surface treatment of (3)Liquid (medicinal liquid). In particular, an aqueous solution containing 10 to 50% by mass of hydrogen fluoride, 6 to 30% by mass of ammonium fluoride, and 30 to 60% by mass of an organic acid can be suitably used. The organic acid is not particularly limited, but is preferably acetic acid, formic acid, propionic acid, or the like. The liquid temperature when the surface treatment liquid is used is preferably 15 to 25 ℃. In particular, it is preferable to use a catalyst comprising HF and NH ₄ F, performing surface treatment on the treatment liquid of acetic acid.

Preferably, the chemical treatment is performed, and after the components of the treatment liquid remaining on the surface of the silica glass are washed with water and a solvent, the silica glass is dried.

The chemical treatment may be performed 1 time, and more preferably, the uneven surface is formed by performing an uneven formation step through the chemical treatment a plurality of times. In the case of performing the chemical treatment a plurality of times, it is preferable that the steps of cleaning the components of the treatment liquid remaining on the surface of the quartz glass with water or a solvent and then drying are included between the chemical treatment steps. The drying before the chemical treatment step is preferably clean drying in a clean environment. In addition, it is preferable that the next chemical treatment is performed immediately after drying.

According to the present invention, it is possible to provide a method for manufacturing a quartz glass jig and a quartz glass jig, which can suppress generation of uneven unevenness (streaks) and reduce the streaks, and can reduce the number of times of treatment for eliminating the streaks, and can achieve excellent uniformity and less streaks even with a smaller number of times of treatment with a chemical solution of 1 to 2 times. By performing the above-described adhering substance removing step and chemical solution treating step on the smooth surface of quartz glass, unevenness of uneven formation of irregularities which are formed by the chemical solution treatment can be reduced even in the case of 1 chemical solution treatment, and a quartz glass jig excellent in appearance can be provided, whereby the chemical solution treatment of the 2 nd time becomes more effective in the case of performing the chemical solution treatment of the 2 nd time.

The quartz glass jig of the present invention is a jig having a surface of at least 20cm on the surface of quartz glass ² The quartz glass jig having the above liquid medicine treatment portion formed with the irregularities as the surface of the surface on which the irregularities were formed, and 10 portions were measured to obtain the quartz glass jigThe standard deviation of the surface roughness Ra of the uneven surface is 1.00 μm or less.

Further, it is preferable that the coefficient of variation in measuring the surface roughness Ra of the uneven machined surface of 10 or more points is 0.60 or less. In this way, for the determination of the uniformity/unevenness of the cloudiness (i.e., uniformity/unevenness of the formation of irregularities) of the silica glass jig, it is preferable that the standard deviation when measuring the surface roughness Ra of the surface on which irregularities are formed at 10 or more sites is 1.00 μm or less, and the coefficient of variation when measuring the surface roughness Ra of the surface at 10 or more sites is 0.60 or less.

The textured surface is preferably a translucent surface which is uniformly clouded.

The degree of cloudiness and transparency of the textured surface is not particularly limited, but it is preferable that the textured surface has a gloss of less than 2 at 60 degrees. In particular, the average value of the glossiness of the uneven surface at 10 or more points is preferably less than 2, and more preferably 1 or less. The maximum value of the glossiness of the textured surface at 60 degrees is preferably less than 2, more preferably 1 or less.

The average value of the visible light transmittance of the uneven surface obtained by the colorimeter is preferably 30% or less, and the standard deviation of the visible light transmittance is preferably 1% or less, more preferably 0.5% or less.

For manufacturing the quartz glass jig of the present invention, the above-described manufacturing method of the quartz glass jig of the present invention can be suitably employed.

In addition, it is preferable that 200mm is not present in the chemical solution treatment portion ² The irregularities in the above range are processed into speckles. Examples of the uneven-processed speckle include speckles of various shapes such as speckles, portions with strong transparency (white turbidity), long streaks formed by a large number of streak patterns, and clusters of fine speckles. In particular, there may be mentioned local speckles having directionality such as speckles of brush patterns and fingerprint marks.

Examples

The present invention will be further specifically described by the following examples, which are given by way of illustration only and are not intended to limit the scope of the present invention.

Example 1

A quartz glass jig (a quartz glass furnace tube for Si wafer treatment in the semiconductor industry, an area of 6000 cm) having a smooth and transparent quartz glass surface (a baking surface by a burner, a mirror polished surface, etc.) without surface treatment was prepared ² ) The quartz glass surface of this quartz glass jig was subjected to HF cleaning with a 5 mass% aqueous HF solution for 15 minutes, and after etching removal of the glass surface layer of the quartz glass surface (etching amount equivalent to 0.45 μm), was subjected to pure water cleaning for 5 minutes. Then, the quartz glass jig was kept at 30℃and a humidity of 40 to 50% for 3 hours or more using a cleaning dryer (grade 1000), and then subjected to cleaning drying.

Next, the 1 st chemical treatment step was started within 30 minutes after the cleaning and drying, and the chemical treatment step of immersing the surface of the quartz glass jig in the surface treatment liquid was performed for 90 minutes. The surface treatment liquid for liquid medicine treatment adopts HF:15 mass%, NH ₄ F:15 mass percent of acetic acid: 35% by mass of an aqueous solution. After the chemical treatment, the substrate was washed with pure water, and then the same cleaning and drying were performed by the cleaning and drying machine.

Next, the chemical treatment process of the 2 nd time is started within 30 minutes after the cleaning and drying. The chemical treatment with the surface treatment liquid, the cleaning with pure water, and the cleaning and drying were performed in the same manner as in the chemical treatment step 1, to obtain a quartz glass jig having a textured surface subjected to the chemical treatment.

The surface of the obtained silica glass jig was cloudy and translucent, and a large distribution of the concentration of the cloudy was not visually observed. In addition, on the surface, 200mm was not present ² The irregularities in the above range are processed into speckles. Fig. 1 shows an electron micrograph of the surface of the silica glass jig obtained in example 1. The lower right scale of the photograph of FIG. 1 is 100 μm. FIG. 5 shows a quartz glass jig obtained in example 1Is a photograph of (2).

The area of the cloudy uneven portion on the surface of the obtained quartz glass jig was measured. A method for measuring the area of a white turbidity uneven portion, wherein a plate material with a black background is used, the portion having a different white turbidity is visually extracted, the area of the portion is obtained from the vertical and horizontal dimensions by approximate estimation, and the ratio of the area to the whole surface area is measured. If there are a plurality of white and turbid portions, the total is measured as an area. The results are shown in Table 1. In table 1, the ratio of the area of the uneven white turbidity portion to the total surface area of the silica glass jig was 25% or less based on the inspection standard of the area of the uneven white turbidity portion, and the case where the ratio exceeds 25% was judged as a defective product. As shown in table 1, the area of the clouded uneven portion on the surface of the silica glass jig obtained in example 1 was 10%.

The surface roughness Ra of the obtained quartz glass jig was measured at Ra measurement sites (measurement sites) of 18 sites using a surface roughness meter (small surface roughness measuring machine "SURFTEST (SURFTEST) SJ-310", manufactured by Mitutoyo corporation). Fig. 4a and 4b are schematic explanatory views showing Ra measurement sites (measurement points) of the method for measuring the surface roughness Ra of the silica glass jig of example 1 by arrows. Fig. 4a is a view of the measurement point from the side of the quartz glass jig (Si wafer processing quartz glass furnace core tube), and fig. 4b is a view of the measurement point from the upper end side of the quartz glass jig (Si wafer processing quartz glass furnace core tube). In fig. 4a and 4b, reference numeral 10 denotes a quartz glass tube which is a quartz glass jig, reference numeral 12 denotes a main body portion of the quartz glass tube, and reference numeral 14 denotes a flange portion of the quartz glass tube.

As shown in fig. 4a, the surface roughness Ra of the inner and outer surfaces (arrow O, P, Q, R, S, T) of the upper, middle and lower sides of the body 12 of the silica glass jig 10 was measured, and as shown in fig. 4b, the surface roughness Ra (18 points) was measured for the inner and outer surfaces (arrow O, P, Q, R, S, T) of the upper, middle and lower sides of the body 12 of the silica glass jig 10, respectively, with the circumference of the body 12 equally divided (120 °). In fig. 4b, the circumferential direction of the main body 12 of the quartz glass jig 10 is equally divided (120 °), and measurement points of the inner and outer surfaces (arrows O1, O2, O3 and R1, R2, R3) of the upper and lower portions are shown.

The upper, middle and lower measuring points are set to an upper measuring point near 20% (10 to 30%) of the full height from the upper end, a central measuring point (within the range of center to + -15%) of the full height center, and a lower measuring point near 20% (10 to 30%) of the full height from the lower end, when the flange portion 14 of the quartz glass furnace core tube 12 as a quartz glass jig is removed from the upper end to the lower end of the cylindrical portion side surface plane as the full height, according to fig. 4a and 4b, which schematically show the measuring points of the surface roughness. The results of the average value, the coefficient of variation, and the like of the surface roughness Ra are shown in table 1.

Further, the glossiness of the obtained silica glass jig was measured at 18 positions by using a gloss meter (gloss tester IG-330 manufactured by horiba corporation) at 60 degrees. The measurement point is a measurement point based on the surface roughness. The average value of the glossiness and the like are shown in table 2.

Further, 10 samples were cut out from the obtained quartz glass jig, and the visible light transmittance (10 points) was measured using a tone meter (MJ-TM 110 manufactured by table co). 10 parts of the sample were cut out, and as shown in fig. 4a, the upper, middle and lower sides (arrow O, P, Q) of the body 12 of the silica glass jig 10 were measured, and as shown in fig. 4b, the circumference of the body 12 of the silica glass jig 10 was equally divided (120 °) and the upper, middle and lower sides (arrow O, P, Q) were each set as the top of the head of the silica glass jig (arrow U, the position opposite to the flange of symbol 14). The average value, standard deviation, and the like of the visible light transmittance obtained by the tone meter are shown in table 2.

TABLE 1

TABLE 2

Example 2

As in example 1, a quartz glass jig having a smooth and transparent surface without surface treatment was prepared, and the quartz glass surface of the quartz glass jig was subjected to HF cleaning and pure water cleaning as in example 1. Then, a dust-free cloth was immersed in ethanol, and the quartz glass jig was wiped with the dust-free cloth, followed by cleaning and drying in the same manner as in example 1.

Next, the 1 st chemical treatment step was started within 30 minutes after the cleaning and drying. According to the same treatment liquid and treatment conditions as in example 1, the surface of the quartz glass jig was subjected to chemical treatment. After the chemical treatment, the substrate was rinsed with pure water. Then, the mixture was dried by a cleaning dryer (grade 1000) at 30℃and a humidity of 50 to 60% for 3 hours or more.

Next, the chemical treatment process of the 2 nd time is started within 30 minutes after the cleaning and drying. In the same manner as in the 1 st chemical treatment step, chemical treatment, washing with pure water, and cleaning and drying were performed. A quartz glass jig having a concave-convex surface subjected to a chemical treatment was obtained.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. The quartz glass jig had a translucent surface with cloudiness, and was not seen to have a large distribution of the concentration of cloudiness by visual observation. In addition, on the surface, 200mm was not present ² The irregularities in the above range are processed into speckles. Table 1 and 2 show the surface roughness Ra, glossiness, average value of visible light transmittance obtained by a tone meter, coefficient of variation, and the like. In this case, the area of the white turbidity unevenness was 5%.

Example 3

In the same manner as in example 1, a quartz glass jig having a smooth and transparent quartz glass surface without surface treatment was prepared, and the quartz glass surface of the quartz glass jig was subjected to HF cleaning and pure water cleaning in the same manner as in example 1. In a space (cleaning room of class 10,000) where the cleanliness is controlled, cleaning and drying are performed for 2 hours or longer using an IR lamp and a hot air dryer (blow-out temperature 80 ℃).

Next, the 1 st chemical treatment step was started within 30 minutes after the cleaning and drying. According to the same treatment liquid and treatment conditions as in example 1, the chemical treatment was performed. After the chemical treatment, the cleaning was performed with pure water, and then, in the same manner as the cleaning and drying after the HF cleaning, the cleaning and drying were performed in a space (cleaning chamber of the order of 10,000) in which the cleanliness was controlled.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. The quartz glass jig had a translucent surface with cloudiness, and was not seen to have a large distribution of the concentration of cloudiness by visual observation. In addition, on the surface, 200mm was not present ² The irregularities in the above range are processed into speckles. Table 1 and 2 show the surface roughness Ra, glossiness, average value of visible light transmittance obtained by a tone meter, coefficient of variation, and the like. In this case, the area of the white turbidity unevenness was 20%.

Example 4

Next, the chemical treatment process was started within 30 minutes after the cleaning and drying. The same treatment liquid as in example 1 was used to carry out the same chemical treatment. After the chemical treatment, the cleaning was performed with pure water, and the same cleaning and drying as the cleaning and drying after the HF cleaning was performed. A quartz glass jig having a concave-convex surface subjected to a chemical treatment was obtained.

As is clear from tables 1 and 2, in examples 1 to 4, the surface of the quartz glass jig was a uniform translucent surface which was uniformly clouded, and a uniform uneven surface was formed in which irregularities were continuously formed. The quartz glass jigs of examples 1 to 4 were able to achieve a good product in which the proportion of the surface area of the non-uniform white portion to the entire quartz glass jig was 25% or less, and the standard deviation was 1 or less and the coefficient of variation was 0.6 or less.

In example 1, the concave-convex processing surface was formed by repeating the concave-convex forming step by the chemical solution treatment 2 times, and fig. 6 shows a photograph of a quartz glass jig in which the concave-convex forming step by the chemical solution treatment was further repeated, and the concave-convex forming step by the chemical solution treatment was performed 4 times in total. As shown in fig. 6, the surface was cloudy and translucent, and the uneven surface was visually inspected to make the streak less noticeable, as compared with the quartz glass jig of fig. 5, to obtain a quartz glass jig having an uneven surface with excellent uniformity.

Comparative example 1

As in example 1, a quartz glass jig having a smooth and transparent quartz glass surface without surface treatment was prepared, and the quartz glass surface of the quartz glass jig was subjected to the same chemical treatment as in example 1 without performing the deposit removal step (HF cleaning, pure water cleaning and drying steps of 5 mass%). After the chemical treatment, the mixture was washed with pure water and dried in the same manner as in example 1.

Next, the chemical treatment process is restarted, and the chemical treatment is performed under the same concentration conditions. After the chemical treatment, the quartz glass jig having the uneven surface was obtained by washing with pure water and cleaning and drying in the same manner as in example 1.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. The quartz glass jig was opaque and translucent, but was uneven, and a portion having a dense white and a portion having a light white and a transparent feel was visible. In addition, on the surface, 200mm was present ² The local unevenness having directivity in the above range is the uneven-processed unevenness. Fig. 2 shows an electron micrograph of a cloudy portion of the surface of the silica glass jig obtained in comparative example 1. The lower right scale of the photograph of FIG. 2 is 100 μm.

When a transparent portion having a thin white turbidity is observed, a portion where no irregularities are formed is visible. Fig. 3 shows an electron micrograph of a portion of the surface of the silica glass jig obtained in comparative example 1, on which no irregularities were formed. The lower right scale of the photograph of fig. 3 is 100 μm.

Table 1 and 2 show the surface roughness Ra, glossiness, average value of visible light transmittance obtained by a tone meter, coefficient of variation, and the like. In this case, the area of the white turbidity unevenness was 30%.

Photographs of the quartz glass jig obtained in comparative example 1 are shown in fig. 7 to 9. Fig. 7 shows a portion corresponding to the upper surface of a quartz glass jig (a quartz glass furnace tube for Si wafer processing) when the quartz glass jig is immersed in a processing liquid and subjected to chemical liquid processing, fig. 8 shows a portion corresponding to the side surface of the quartz glass jig, and fig. 9 shows a portion corresponding to the lower surface of the quartz glass jig. In fig. 7 to 9, it is apparent that the speckles 16, 18, and 20 are present, respectively. In particular, in fig. 8 (b), the patch 18 is a streak-like patch, and is a local patch having directivity.

Comparative example 2

A quartz glass jig having a smooth and transparent quartz glass surface without surface treatment was prepared in the same manner as in example 1, and the quartz glass surface of the quartz glass jig was cleaned with pure water for 1 minute (corresponding to an etching amount of 0.03 μm) in the same manner as in example 1 except for the cleaning time. The mixture was kept at 30℃and a humidity of 50 to 60% for 3 hours or more with a clean dryer (grade 1000) to carry out clean drying. The dried silica glass jig was insufficient in removal of the adhering matter by HF cleaning, and the adhering matter remained on the surface of the silica glass.

Next, within 30 minutes after the cleaning and drying, the 1 st chemical treatment was performed in the same manner as in example 1. After the chemical treatment, the cleaning and the drying by pure water were performed in the same manner as in example 1, and further the chemical treatment, the cleaning and the drying by pure water were performed again in the same manner as in example 1. A quartz glass jig having a concave-convex surface subjected to a chemical treatment was obtained.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. In the silica glass jig obtained in comparative example 1, the surface was cloudy and translucent, but the portion where the cloudiness was strong and the portion where the cloudiness was thin and had a transparent feel were uneven. In addition, on the surface, 200mm was present ² The local unevenness having directivity in the above range is the uneven-processed unevenness. When a transparent portion having a thin white turbidity is observed, a portion where no irregularities are formed is visible.

Table 1 and 2 show the surface roughness Ra, glossiness, average value of visible light transmittance obtained by a tone meter, coefficient of variation, and the like. In this case, the area of the white turbidity unevenness was 35%. Fig. 10 shows a photograph of the quartz glass jig obtained in comparative example 2. In fig. 10 (a), it is seen that there is a local streak having directivity, namely, a streak-like streak 22, and in fig. 10 (b), it is seen that there is a streak 24 of an aggregate of small streaks.

Comparative example 3

As in example 1, a quartz glass jig having a smooth and transparent quartz glass surface without surface treatment was prepared, and the quartz glass surface of the quartz glass jig was cleaned with 5 mass% HF as in example 1, and then cleaned with pure water and generally dried.

After storage for 24 hours in an environment where cleanliness was not controlled, chemical treatment was performed in the same manner as in example 1. After the chemical treatment, the cleaning with pure water and general drying were performed, and the chemical treatment, the cleaning with pure water, and the cleaning and drying were further performed again as in example 1. A quartz glass jig having a concave-convex surface subjected to a chemical treatment was obtained.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. The quartz glass jig was transparent and cloudy on the surface, but was uneven, and a portion with a thick white and a portion with a thin white and a transparent feel were observed. In addition, on the surface, 200mm was present ² The local unevenness having directivity in the above range is the uneven-processed unevenness. In fig. 11, a photograph of the quartz glass jig obtained in comparative example 3 is shown. In fig. 11 (a), it is seen that there is a streak-like streak 26 which is a local streak having directionality, and in fig. 11 (b), it is seen that there is a large-area streak 28.

Comparative example 4

The quartz jig used in the film formation process was immersed in a pure water tank, and then immediately subjected to the same chemical treatment as in example 1 without drying.

After the chemical treatment, the cleaning with pure water and general drying were performed, and the chemical treatment, the cleaning with pure water, and the cleaning and drying were further performed again as in example 1. A quartz glass jig having a concave-convex surface subjected to a chemical treatment was obtained.

The obtained quartz glass jig was subjected to the respective measurements by the same measurement method as in example 1. The results are shown in tables 1 and 2. The quartz glass jig was opaque and translucent on the surface, but was uneven, and a thick white portion and a thin transparent portion were visible. In addition, on the surface, 200mm was present ² The local unevenness having directivity in the above range is the uneven-processed unevenness.

As is clear from tables 1 and 2, in comparative examples 1 to 4, the surface of the quartz glass jig was not uniformly clouded, and was not formed as a uniform uneven surface having continuously formed irregularities. The quartz glass jigs of comparative examples 1 to 4 were defective products in which the proportion of the surface area of the non-uniform white portion to the entire surface area of the quartz glass jigs was 30% or more, and the surface roughness was not achieved with a standard deviation of 1 or less and a coefficient of variation of 0.6 or less.

The quartz glass jig of the present invention obtained in the above-described manner can be used as a material for semiconductor processing, optical, physical and chemical machine, decoration, and the like. In particular, it is suitable for use as a quartz glass jig for use in semiconductor manufacturing processes for manufacturing semiconductors.

Symbol description

10 Quartz glass furnace core tube

12 main body part

14 flange portion

16. 18, 20, 22, 24, 26, speckle

O, P, Q, R, S, T, O1, O2, O3, R1, R2, R3 arrows showing measurement points of the surface roughness Ra

U arrow for displaying measurement point of visible ray transmittance

Claims

1. A method for manufacturing a quartz glass jig, which is formed by treating a surface with a chemical solution to form irregularities, comprises:

an adhering matter removing step of removing adhering matter on the smooth quartz glass surface; and

a processed surface forming chemical treatment step of forming a textured surface on the quartz glass surface from which the adhering matter has been removed by the formation of irregularities by the chemical treatment,

the standard deviation of the surface roughness Ra of the uneven surface at 10 or more points is 1.00 μm or less.

2. The method for manufacturing a silica glass jig according to claim 1, wherein the roughness of the surface of the textured surface is less than 2 at 60 degrees of gloss,

the average value of visible light transmittance of the uneven surface obtained by a tone meter of 10 or more points is 30% or less and the standard deviation is 1% or less.

3. The method for manufacturing a silica glass jig according to claim 1, wherein a coefficient of variation in measuring surface roughness Ra of the uneven machined surface at 10 or more points is 0.60 or less.

4. The method for manufacturing a silica glass jig according to claim 1, wherein the adhering substance removing step comprises:

an HF cleaning step of removing the adhering matter on the surface of the smooth quartz glass by using a cleaning liquid containing HF;

a first removal step of diluting and removing HF components remaining on the surface of the quartz glass with water after the HF cleaning step; and

and a second removal step of removing the adhering moisture and/or adhering solvent remaining on the surface of the silica glass after the first removal step.

5. The method for manufacturing a quartz glass jig according to claim 4, wherein in the HF cleaning step, a glass surface layer of the quartz glass surface is etched away by 0.10 μm or more.

6. The method for manufacturing a silica glass jig according to claim 4, wherein the second removing step is a drying step of drying the silica glass surface in a clean atmosphere having a humidity of less than 60%.

7. The method for manufacturing a quartz glass jig according to claim 1, wherein the chemical treatment is performed using a chemical solution containing HF and NH ₄ F and acetic acid.

8. A quartz glass jig having a surface of at least 20cm ² The quartz glass jig has a chemical solution treatment portion formed with irregularities in the above area, wherein the standard deviation of the chemical solution treatment portion as a surface roughness of the surface roughness Ra of the surface roughness of 10 or more portions is 1.00 [ mu ] m or less.

9. The quartz glass jig of claim 8, wherein the relief machined surface has a gloss of less than 2 at 60 degrees gloss meter,

10. The quartz glass jig according to claim 8, wherein a coefficient of variation in measuring surface roughness Ra of the roughened surface at 10 or more points is 0.60 or less.

11. The quartz glass jig according to any one of claims 8 to 10, wherein the quartz glass jig is manufactured by the manufacturing method of the quartz glass jig according to any one of claims 1 to 7.