JP2009102195A - Surface reforming apparatus for tubular glass article and manufacturing method of tubular silica glass jig - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a cause for the formation of new particles, in the treatment of the surface of a glass tube, and to provide a surface having fine projections and recessions with uniformity, high precision and reproducibility. <P>SOLUTION: A laser beam generated by a laser oscillation means 2 is guided to a light guide means 3 and irradiated from an irradiation means 5 at its tip. The laser beam irradiated from the irradiation means 5 is uniformly irradiated on the inner peripheral surface of a glass tube 6 to be treated since the light guide means 3 is rotated at one revolution/second by a rotation driving device 33 installed inside a horizontal arm 31. Since the rotation of the laser guide means 3 and the horizontal transfer of a transfer means 4 are synchronized and the transfer means 4 transfers the article to be treated 6 a specified distance when the irradiation means 5 rotates one turn, fine projections and recessions are formed at regular intervals on the surface of the glass tube 6 and the surface treatment by a laser beam is applied. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, fine irregularities are formed on the surface of a tubular glass body, in particular, a tubular quartz glass jig used in a semiconductor manufacturing jig, a film forming apparatus, a plasma processing apparatus, a heat treatment apparatus, etc. in semiconductor manufacturing. The present invention relates to a surface modification device and a modification method.

  When forming a nitride film on the surface of a semiconductor wafer such as silicon in the film-forming process in the manufacture of semiconductors, quartz glass is used inside the reaction tube because it is highly pure and heat-resistant and easy to process. A furnace core tube (inner tube) is used. These quartz glass jig surfaces are usually transparent and smooth. The transparent and smooth surface is good for semiconductor manufacturing because there is no stagnation of reaction gas or trapping of by-products after the reaction. Separation of reaction products such as a nitride film attached to the surface of the glass jig and generation of particles due to dust generation from the quartz glass jig itself have become problems.

That is, the film is deposited on the reaction tube made of quartz glass such as the inner tube by the film formation of the nitride film, and the deposited film becomes thick by the repeated film formation, due to the difference in thermal expansion coefficient between the film forming material and the quartz glass. However, there are problems that the reaction tube is cracked or the adhered film is peeled off to contaminate the film formation substrate. Further, since the film adhering to the reaction tube is difficult to be removed even by the hydrofluoric acid treatment of the reaction tube, the reaction tube may be significantly eroded in a portion where the adhering film is small (thin). Further, in a heat treatment furnace using a quartz glass tube as the furnace core tube, there is a problem that the thermal energy in the electric furnace leaks to the outside as a heat ray because the quartz glass is excellent in transparency, and the thermal efficiency is lowered.
For this reason, in order to raise the adhesion strength of the film | membrane adhering to a quartz glass jig | tool, to prevent peeling of a film | membrane and to suppress particle generation, forming a fine unevenness | corrugation on the quartz glass surface is performed. Specifically, a physical surface treatment such as a sand blast treatment or a chemical surface treatment for forming irregularities by etching the surface with a chemical such as hydrogen fluoride has been proposed.

Japanese Patent No. 2502109 JP 2001-89198 A JP 2004-238262 A

However, when irregularities are formed on the quartz glass surface by sandblasting, which is the physical surface treatment method, the surface area is increased and the adhesion of the film is improved, but at the same time, micro-cracks are formed on the quartz glass surface, In some cases, the microcracks may accumulate quartz fine powder that has been scraped off during the sandblasting process, and these may be released from the microcracks during the semiconductor manufacturing process and cause particle contamination. As described above, the sandblast treatment is not preferable because the occurrence of microcracks and the presence of microchipping cannot be avoided, and the strength of the member is reduced.
Further, even during the semiconductor manufacturing process, if a reaction gas enters the microcrack, a by-product is generated inside the microcrack, which may cause particle contamination, which is not preferable.

On the other hand, chemical surface treatment that forms irregularities by etching the surface with a chemical such as hydrogen fluoride is superior in that there is no generation of particles due to the formation of microcracks, but local treatment of the surface is difficult. In addition, it is difficult to control the surface roughness to a desired level, and the work process is complicated.
Further, the shape of the irregularities on the quartz glass surface by etching is a dimple shape, and the crest portion of the outer peripheral portion of the dimple has a sharp shape. These sharp peaks are easily chipped by contact with the wafer, and there is a risk that the chipped quartz powder becomes particles. In addition, immersing in an aqueous hydrogen fluoride solution for a long time to form irregularities on the surface may cause hydrates generated in the aqueous solution to deposit on and adhere to the quartz glass surface and cause new particles. .

Even in surface treatment that combines sandblasting and etching treatment, if the cleaning after sandblasting is incomplete, by-products and quartz fine powder are likely to be generated from the inside of the cracks, and particles in the aqueous hydrogen fluoride solution during etching. Reattachment may occur.
As described above, the conventional method for roughening the surface of the quartz glass has a possibility that a new cause of the generation of a partile is generated as a secondary factor. In addition, due to high integration of semiconductors, high accuracy is required for the quartz glass jig itself, and the surface uneven surface is also required to be a uniform uneven surface with good reproducibility. In any of the surface forming methods, a uniform and reproducible high-precision uneven surface could not be obtained. Further, all of the formed uneven surfaces were dimple-shaped and discontinuous.
When the surface treatment target is tubular, there has been no apparatus for uniformly irradiating the surface with laser.
In the surface treatment of a tubular quartz glass jig, the present invention suppresses generation of the cause of particle generation in the treatment process, and enables formation of a fine uneven surface with uniformity, high accuracy, and reproducibility. It is intended.

It has laser oscillation means, laser light guiding / irradiation means for introducing and irradiating laser light onto the surface of the glass tube, glass tube holding means, and glass tube feeding means. A fine uneven layer with a roughness Ra of 0.5 to 50 μm is formed on the surface of the tool, and the cross-sectional shape of the unevenness is a V shape, a square groove shape, a semicircular shape, or a combination thereof. .
The interval between the concaves and convexes is in the range of 0.1 to 1 mm, and the accuracy can be within ± 10% at any value within this range. Further, the depth of the unevenness can be a uniform uneven surface with an accuracy within ± 10% in the range of 1 to 100 μm.

In the processing operation on the surface of quartz glass jig, by creating a relational expression between the relative traveling speed of the laser irradiating the quartz glass surface and the surface roughness after irradiation, the traveling speed corresponding to the required surface roughness. It is possible to control the surface roughness by moving the laser.
The laser output is preferably more than 10 W to less than 2 KW, and the type of laser is high energy such as XeF (351 nm), XeCl (308 nm), KrF (248 nm), ArF (193 nm), etc., or YAG laser. Although it is possible to use a laser to focus the inside of the quartz glass jig, the carbon dioxide laser with good versatility and operability is preferable for processing the surface layer of the quartz glass jig. Since the wavelength of the carbon dioxide laser does not pass through the quartz glass, it is focused on the surface of the quartz glass jig and modified from the surface.

Lasers are widely used as various processing means such as welding, cutting, drilling, and marking of various materials, all of which perform point or line processing and modify the surface properties over the entire surface layer. It was not used for quality processing.
High power of 2KW or more is desirable for laser welding, cutting, etc., and 10W is sufficient for marking, but laser surface modification is preferably in the middle of more than 10W to less than 2KW. More than 30W and less than 1KW are more preferable, and 50W to 400W is more desirable in the surface modification of the glass tube.
When the laser output is low, the processing speed is low in the surface modification of the quartz glass tube by the laser, which is not practical, and when it is too high, it becomes difficult to control the shape of the irregularities formed on the surface of the quartz glass tube.

In addition, since the relative travel speed when the irradiation laser moves on the surface of the object to be processed and the surface roughness after irradiation are inversely proportional, the desired unevenness can be accurately formed by selecting the travel speed using this relationship. It can be done.
Since the traveling speed of the laser can be obtained from the desired surface roughness, the target surface roughness can be reliably processed. When forming a fine concavo-convex layer with a surface roughness Ra of 0.5 to 50 μm, the horizontal axis represents the surface roughness of 0.5 to 50 μm, especially 1 to 30 μm, and the vertical axis represents the laser traveling speed (line speed). Then, the surface of the quartz glass jig is processed by determining the laser traveling speed corresponding to the desired surface roughness.

  In general, commercially available laser markers, etc., do not move the laser machine body, but use the optical system such as a condensing lens and a reflecting mirror to mark characters on the surface. The irradiation means can be rotated and a holding means for enabling the tubular quartz glass jig itself to be surface-treated to be moved or rotated, and a laser beam is irradiated while the glass tube holding means is moved or rotated. By doing this, surface processing is performed on semiconductor manufacturing jigs such as quartz glass reaction tubes and quartz glass tubes for etchers, which are CVD jigs used in plasma etching.

It is possible to form a plurality of regions with different surface roughness by changing the laser processing conditions, and by changing the laser irradiation pitch, speed, etc. , A square groove, a semicircular shape, or a combination thereof can be produced. FIG. 2 shows a conceptual diagram of the cross-sectional shape of the unevenness that can be formed by a laser.
(1) is a V-shaped groove formed on the surface, (2) is a trapezoidal groove formed without a gap to form a triangular protrusion, and (3) is a trapezoidal shape. Grooves are formed with an interval, and (4) is a semicircular groove formed with an interval.

  The cross-sectional shape of the groove is wide by taking the laser irradiation pitch as an arbitrary numerical value, so that the upper surface forms a V-shaped groove with a width of an arbitrary dimension, or the irradiation pitch is narrowed. By repeating the irradiation a plurality of times, it is possible to process the cross-sectional shape of the groove at the bottom into a planar shape having an arbitrary dimension. In addition, the groove shape can be controlled by changing the focal position of the laser in the work piece to form a semicircular groove or changing the triangular groove angle.

  What controlled the surface roughness by laser irradiation has a great advantage that a quartz glass jig having a concavo-convex surface finished as a transparent baked finished surface can be obtained, unlike a conventional surface treatment by sandblasting or etching. The surface layer is heated by laser irradiation, and the fine irregularities become a highly transparent surface layer having the same gloss as the baked finish surface.

  The present invention comprises laser oscillation means, laser light guide means for guiding a laser to the surface of the glass tube, laser irradiation means provided at the tip of the laser light guide means, glass tube holding means, and glass tube feed means. A uniform and fine uneven surface can be formed with high accuracy on the surface of the tubular quartz glass jig.

Example 1
FIG. 1 is a schematic view of a glass tube surface modifying apparatus of the present invention.
The laser oscillation device 2 is a device for oscillating a carbon dioxide laser with an output of 100 W, and is fixed to one end side on the earthquake-resistant table 1. In the vicinity of the laser oscillating device 2, a feed means 4 is installed which is movable in one direction extending to the other end side of the earthquake-resistant table 1. In this embodiment, a linear actuator that is a single-axis robot for feeding is used, but the present invention is not limited to this.
The laser emitted from the laser oscillating means 2 is guided to the laser light guiding means 3 made of a glass tube and irradiated from the irradiation means 5 provided at the tip of the laser light guiding means 3.
The laser light guiding means 3 includes an arm holding base 30 provided on the laser oscillation means 2 side and a hollow arm 31 extending horizontally from the arm holding base 30 on the earthquake resistant table 1. In the hollow arm 31, a laser light guide tube 32 for guiding a laser whose one end is rotatably connected to the laser emission port of the laser oscillation means 2 is provided through the arm holding base 30. A laser irradiation means 5 is provided at the other end of the laser beam. The laser light guide tube may be anything as long as it does not react with the laser light and has a light shielding property, but in this embodiment, it does not react with the carbon dioxide laser and is made of aluminum that does not dissipate the laser light. The light guide tube was used.
The laser irradiation means 5 is attached at right angles to an aluminum tube 32 which is a laser light guide tube using a known optical transmission part. The mirror attached to the upper part of the head of the optical transmission part bends the laser beam that has passed through the aluminum tube 32 by 90 °, as in Utility Model Registration No. 2117356 (Act No. 7-43848). The laser guided to the aluminum tube 32 in this way is changed in direction at right angles at the tip of the aluminum tube 32 and is emitted from the tip of the laser irradiation means 5.

On the distal end side of the hollow arm 31, there is provided a rotation driving device provided with an electric motor that supports the aluminum tube 32 and applies a rotational force to the aluminum tube 32. The rotary drive device of the present embodiment used a known hollow rotary actuator. An optical transmission part as an irradiating means attached to the tip of the aluminum tube 32 is obtained by holding the aluminum tube 32 of the light guide means in the hollow portion of the hollow rotary actuator and rotating the aluminum tube 32 by the rotation of the motor of the hollow rotary actuator. Rotate. As the laser irradiation means 5 rotates in this way, the laser light emitted from the laser irradiation means 5 rotates 360 degrees around the aluminum tube 32 as an axis.
A quartz glass tube 6 having an inner diameter of 198 mm, a thickness of 6 mm, and a length of 600 mm was set and fixed to the holding means 41 in this surface modification device. Adjustment is made so that the aluminum tube 32 of the laser light guide means is positioned at the center of the glass tube 6, and when the tip of the irradiation means 5 is rotated, the distance is always constant from the inner surface of the glass tube 6 to be processed. Set to. Further, the feed means 4 is moved at a slow speed so that the tip of the quartz glass tube 6 is located at either the bottom or the opening of the glass tube 6, and the position is adjusted.
When the irradiation means 5 rotates the inside of the quartz glass tube by the rotation driving means 33 while irradiating the laser from the tip, the laser is irradiated to the inner surface of the glass tube 6 to be processed while the irradiation means 5 circulates in the glass tube.

The rotation speed was 1 rotation / sec. The feed is synchronized with the rotation so that the traveling table 4 is moved by 0.05 mm for each rotation so that the surface treatment is performed uniformly. Thus, when the fine uneven surface was formed in the inner surface of the quartz glass tube 6, the uniform uneven surface was obtained.
FIG. 3 shows a photograph in which a fine irregular surface is formed on the inner surface of a quartz glass tube. FIG. 3A is a photograph of the transparent quartz glass tube after the laser surface modification. For comparison, the central part is not irradiated with the laser and remains unmodified. The upper and lower sides of the quartz glass tube are formed by forming fine irregular surfaces on the inner surface of the tube by laser modification. FIG. 3B is a photograph of the outer surface of the quartz glass tube whose inner surface is modified, and FIG. 3C is a photograph of the inner surface of the quartz glass tube. It can be seen that the outer surface of the tube is smooth and transparent, and the inner surface of the tube is rough with fine irregularities.

It goes without saying that the quartz glass tube 6 itself to be processed can be rotated to form fine irregularities on the inner surface of the glass tube. However, the glass tube has an attachment such as a tail tube, and the tube itself is Since there are some that cannot be rotated, the one that rotates the laser irradiation section itself has higher applicability because the surface modification is performed with the glass tube fixed.
When rotating the quartz glass tube 6 itself, one or both ends of the quartz glass tube 6 are used by using one or two rotating heads which are chucks installed so as to be movable on the guide rail serving as the feeding means 4. The holding means can be selected according to the shape of the tubular quartz glass jig to be processed, such as one that holds and fixes the surface portion.

Hereinafter, a test example will be described regarding the relationship between the relative movement speed of the laser and the object to be processed and the surface roughness of the obtained surface when the uneven surface is formed using a laser.
Test example 1
A carbon dioxide laser with an output of 100 W was used. A quartz glass plate for an etcher (processed surface: 70 mm square × 2 mm) optically polished was used as an object to be processed.
Laser movement speed was irradiated at 100 mm / sec, and linear grooves were formed in a lattice pattern at a pitch of 0.1 mm on the surface of the quartz glass plate to form fine uneven surfaces. FIG. 4 shows a photograph of a state where the quartz glass plate surface is formed in a lattice shape.
The pitch interval of the grid-like uneven surface is 0.1 mm, the accuracy is a uniform surface within ± 10%, the depth of the recess is 50 μm, and the uniform uneven surface within ± 10% is accurate. Obtained.

Test example 2
Using a carbon dioxide laser with an output of 100 W, the laser traveling speed was changed in a state where the quartz glass plate was allowed to stand to form a fine uneven surface. The processing time was different depending on the running speed, and the surface condition at this time was observed. Table 1 shows the results of measuring the processing time and the surface roughness of Ra (μm) and Rt (μm) with a pointer-type roughness meter and a three-dimensional surface roughness meter. It can be seen that the processing time and the surface roughness are proportional.

Test example 3
A fine uneven surface was formed on the surface of the quartz glass plate according to Test Example 2 except that the laser output was changed to 30 W. Table 2 shows the results of testing the processing time, Ra (μm), and Rt (μm), and measuring the surface roughness with a pointer-type roughness meter. Compared to the sample irradiated with 100 W laser in Test Example 2, it can be seen that it takes about 15 times longer to process the surface having the same surface roughness.

The schematic diagram of the tubular glass body surface modification apparatus of this invention. The cross-sectional schematic diagram of a micro uneven | corrugated shaped body. A photograph of the surface of a laser-modified quartz glass tube. A surface photograph of a lattice pattern by laser processing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seismic stand 2 Laser oscillator 3 Laser light guide means 32 Laser light guide tube 33 Rotation drive means 4 Feed means 41 Holding means 5 Laser irradiation means

Claims (5)

A tubular glass body surface modification apparatus comprising laser oscillation means, laser light guiding means, laser irradiation means, tubular glass body holding means, and tubular glass body feeding means. 2. The tubular glass body surface modification device according to claim 1, wherein the laser irradiation means is attached to the tip of the laser light guide means so as to change the irradiation direction, and is provided with a rotation driving means for rotating the laser irradiation means. 2. The tubular glass body surface modification device according to claim 1, wherein the laser irradiation means is attached to the tip of the laser light guide means so as to change the irradiation direction, and is provided with a rotation driving means for the tubular glass body. 4. The tubular glass body surface modification device according to claim 2, wherein the movement of the feeding means of the tubular glass body is synchronized with the rotation of the rotation driving means. Tubular quartz which uses the glass tube surface modification device according to any one of claims 1 to 4, holds a tubular quartz glass jig by a glass tube holding means, and forms a fine uneven surface on the surface of the tubular quartz glass jig. Manufacturing method of glass jig.