JPH11156564A - Heat resistant transparent member and manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an internal mark without traces such as a crack, a cutting trace, and an indentation of an outer surface which cause the contamination by focusing a focal point of a transmission laser light on a required internal portion position inside a heat resistant transparent body, and concentrating the energy. SOLUTION: A scanning optical system is arranged at the position of 1/2 thickness of a body 5 of a quartz glass substrate for a photomask with, for example, thickness of 6.5 mm which is manufactured in a required dimension and washed cleanly, in a manner that a center shaft 13b of a second laser light 11b forming a fine focal point of 10 μm diameter is crossed at the angle of 15 deg. against a center shaft 13a of a first laser light 11a adjusted to focus a focal point 14a of the 2 mm diameter. The laser lights 11a, 11b are oscillated and a regular triangle is drawn on the focal point 14a face by the light 11b. Then, the energy density is heightened to dissolve the face by overlaying the lights 11a, 12b so as to form a vivid internal mark 12 which has the regular triangle at the internal position of the body 5 and comprises three lines.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant transparent body such as quartz glass, and more particularly, to a heat-resistant transparent body having a mark inside its main body and a method of manufacturing the same.

[0002]

2. Description of the Related Art Positioning marks and optically readable marks on the outer surface of a semiconductor silicon wafer or a heat-resistant transparent material such as quartz glass used in a manufacturing process for process control and inventory control in the manufacturing process of the semiconductor industry. Signing has been done.

[0003] Orientation flats and notches provided on the outer surface of a silicon wafer are typical marks, but particles or the like generated from these orientation flats or notches are super LS of a semiconductor device.
With the introduction of I, measures against contamination problems have become more important in order to affect contamination problems in silicon wafers and manufacturing processes.

However, since the silicon wafer is an opaque material, there is no other way than to mark the outer surface.

On the other hand, quartz glass has high purity, heat resistance,
Because it has many excellent properties such as low expansion, high hardness, chemical resistance, high transparency, etc., semiconductor industry, chemical industry,
Used in a wide range of fields, such as the precision machinery industry and the space industry.

[0006] In many applications, it is often necessary to make a mark on a quartz glass product because precision alignment or process control is required.

In order to meet this demand, a quartz glass substrate of a photomask used in a semiconductor manufacturing process is also mechanically formed on one or more corners of a square photomask substrate 1 as shown in FIG. A chamfer was made and a notch 2 for a mark was formed. Particles and the like are generated from the chamfered portion, or scattered, and contamination during the process is locally attached to the chamfered portion, which has been a problem.

In addition, the quartz glass product for a semiconductor manufacturing process and the method for manufacturing the same described in Japanese Patent Application Laid-Open No. 8-245230 have a high purity carbon, silicon, silicon carbide or silicon nitride or A colorant 3 which is a mixture with quartz glass is applied to the surface of a quartz glass furnace core tube 4 used in the oxidation / diffusion process of semiconductor manufacturing in a structure having the structure shown in FIG. Are disclosed in which a colorant is applied to the symbol-shaped groove.

[0009]

When a mark is applied to the outer surface by applying a mechanical or thermal external force, some scars remain on the substrate surface, which may be a source of particles or the like.

Japanese Patent Application Laid-Open No. 8-245230 discloses a method in which a colorant is applied to the surface of glass or a colorant is applied to grooves in a symbolic manner on the surface. Not only is there any doubt about the durability and reliability in long-term use, but also plays a role as a negative of the burn-in circuit in the photolithography process of ultra LSI production, and extremely demands for high purity, ultra-high flatness, and high smoothness It is unsuitable for the quartz glass photomask substrate from the viewpoints of purity, flatness, and smoothness.

Particularly, in the semiconductor industry and the optical instrument industry, dirt such as particles is extremely strictly controlled, and high purity, does not contaminate a silicon wafer and a use environment, and has high flatness and high smoothness. There has been a demand for a heat-resistant transparent body such as quartz glass that is suitable for a kept photomask substrate or the like.

The present invention has been made in view of the above-described circumstances, and has an internal mark formed by concentrating the energy of a laser beam at a predetermined position inside a heat-resistant and transparent main body, thereby reducing contamination. It is an object of the present invention to provide a heat-resistant transparent body having no traces such as cracks, shavings, indentations, etc. on the outer surface that cause the heat-resistant transparent bodies, and a method for producing the heat-resistant transparent bodies.

[0013]

Means for Solving the Problems To achieve the above object, the invention of claim 1 of the present application is directed to a heat-resistant transparent body having a heat-resistant and transparent main body and a mark attached to the main body. The mark is a heat-resistant transparent body characterized in that the mark is an internal mark formed by focusing the oscillation laser light at an internal position where the mark is provided in the main body and concentrating energy.

According to a second aspect of the present invention, a plurality of laser beams are simultaneously incident at different incident angles so as to focus on a predetermined internal position in a heat-resistant and transparent main body. The gist of the present invention is to provide a heat-resistant transparent body characterized by increasing the energy density and forming an internal mark in the main body.

According to a third aspect of the present invention, there is provided a heat-resistant transparent body according to the first or second aspect, wherein the heat-resistant and transparent main body is made of quartz glass.

According to a fourth aspect of the present invention, there is provided a heat-resistant transparent body according to the first or second aspect, wherein the heat-resistant and transparent main body is a quartz glass substrate of a photomask. .

According to a fifth aspect of the present invention, there is provided a heat-resistant transparent body according to the first or second aspect, wherein the internal mark is an information medium.

According to a sixth aspect of the present invention, there is provided a heat-resistant transparent body according to the first or second aspect, wherein the internal mark is a bar code.

According to a seventh aspect of the present invention, a heat-resistant and transparent main body is prepared, the energy of the oscillation laser is focused on a predetermined internal position in the main body, and energy is concentrated to form an internal mark in the main body. The gist of the invention is a method for producing a heat-resistant transparent body.

According to an eighth aspect of the present invention, a plurality of oscillated laser beams are simultaneously incident so as to focus on a required internal position in the main body, the superimposed energy density of the oscillated laser beams is increased, and an internal mark is formed in the main body. The gist of the present invention is a method for producing a heat-resistant transparent body according to claim 7.

According to a ninth aspect of the present invention, there is provided a method for manufacturing a heat-resistant transparent body according to the seventh or eighth aspect, wherein the heat-resistant transparent body is a quartz glass substrate of a photomask. .

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a heat-resistant transparent body and a method for producing the same according to the present invention will be described with reference to the accompanying drawings.

The heat-resistant transparent body according to the present invention, for example, a quartz glass substrate 1 is a substrate for a photomask used in photolithography for VLSI, is formed of SiO2 as a single component, and has a vertical length of 152 mm. Side w; 152
mm, thickness t: 6.3 mm.

The main body 5 of the substrate 1 is a transparent body excellent in heat resistance, and has a front surface 6 to which a photoresist is applied in a later photomask manufacturing process, a back surface 7, a side surface 8, a square curved surface 9, and a thread chamfered portion. It consists of ten. An internal mark 12 provided by the laser 11 is provided at a required internal position of the main body of the main body 5, for example, at a position near the curved surface 9 and at a position having a thickness of の inside the main body 5.

In general, the quality required for a photomask substrate is (1) surface defects (scratch, dirt, foreign matter, etc.),
(2) Internal defects (bubbles, foreign matter, striae, etc.), (3) Surface accuracy /
Flatness (including warpage and undulation), (4) external processing accuracy (size, average thickness), (5) transmittance (at 365, 4
04, 436 nm) and (6) Coefficient of thermal expansion.

Therefore, the main body 5 needs to be made of high-purity quartz glass, and the front surface 6 and the back surface 7 as well as
The side surface 8, the square curved surface 9, and the yarn chamfered portion 10 are also optically polished with high precision.

Next, a method of manufacturing the substrate 1 having the mark 12 provided inside the main body 5 will be described with reference to FIG.

A quartz glass ingot is manufactured by a synthesis method, and the ingot is sized to a predetermined size, for example, 155 m.
It is formed into a m-shaped column by a molding machine. Thereafter, the molded body is cut into a predetermined thickness, for example, 6.5 mm to form a flat plate. This flat plate is ground to obtain a flat surface, then chamfered, and further subjected to a second grinding for smoothing.

After polishing for mirror finishing, cleaning is performed to remove the abrasive.

A laser beam 11 oscillated from a laser device (not shown) by a method described in detail below at a required internal position of the main body 5 of the substrate 1 manufactured to a predetermined size and cleaned.
The internal mark 12 is attached using a and 11b.

The substrate 1 is placed at a predetermined position, a focal point having a predetermined size, for example, a diameter of 2 mm is created, and the central axis 1
The first laser beam 11a having the center 3a has its focal point 14a set to, for example, 1/2 of the thickness of the main body 5, that is, from the surface 3.
The setting position of the condenser lens or the concave mirror of the scanning optical system (not shown) is adjusted so as to be connected at a distance of 2 mm. Next, the second laser beam 11b oscillated from another laser device
Is used. The second laser beam 11b produces a minute focus of a predetermined size, for example, a diameter of 10 μm, and the center axis 13b of the second laser beam 11b is set to the first laser beam 11a.
Of the first laser beam 11a at the same position as the focal point 14a of the first laser beam 11a.
A scanning optical system (not shown) is arranged so as to connect 4b.

Thereafter, the laser beam 11a is oscillated to create a focal point 14a having a diameter of 2 mm at a required internal position in the main body 5, while the second laser beam 11b is oscillated to produce the focal point 11a.
A focal point 14b is created at the same position as that of the laser light 1 so that an equilateral triangle is formed at the center of the focal point 11a.
Injured at 1b. At this time, at the position of the focal point 11a injured by the second laser 11b, the energy is concentrated by the superposition of the first laser light 11a and the second laser light 11b, the energy density is increased, and the laser is melted. An internal mark 12 having an equilateral triangle and consisting of three lines is clearly formed at a required internal position of the main body 5 at the position.

In this manner, the mark 12 is provided inside the main body 5.
The substrate 1 marked with is inspected and shipped. Also at this inspection stage, since the marks 12 were formed in the main body 2 without contact with the substrate 1 by the laser beams 11a and 11b, the substrate 1 was chamfered by a mechanical processing method to form the notch 2 for the marks. Not only is it unnecessary, but also the surface 6, as well as the back surface 7, the side surface 8, the square curved surface 9, and the yarn chamfered portion 10, can not have any traces such as cracks, cuts, indentations, etc. on the outer surface that cause dirt.

Note that, in addition to the above-described embodiment, marks described below can be added.

As shown in FIG. 4, the laser beam 11a and the laser beam 1
1b is transmitted from two orthogonal side surfaces 8, and the focal point 14a of the laser 11a and the focal point 1
The energy can be concentrated so as to connect the lines 4b to form the vertical linear mark 12.

As shown in FIG. 5, when the energy is concentrated so as to connect the focal point 14a of the first laser beam 11a and the focal point 14b of the second laser beam 11b, and the laser beam 8b is used to scribe the bar code, A bar code is formed as the internal mark 12, and efficient production management can be performed using an optical reading device.

It should be noted that the provision of the bar code is performed by using only the laser beam 8b so that the bar code is provided.
It is possible to transmit for a longer time than using two laser beams 8a and 8b. In this case, the laser beam 8b
It is possible to reduce the time by increasing the output of.

As shown in FIG. 6, it is also possible to focus on the focal point 14a in the vicinity of the curved surface 9 using only one laser beam 11a, concentrate energy, and form a circular mark 12.

In the heat-resistant transparent body according to the present invention, since the mark 12 is formed inside the main body 5, there is no need to apply a colorant made of a different material from the main body to the surface 6 of the substrate 1 to make the mark. There is no problem in reliability at all even when the quartz glass furnace core tube used under severe conditions such as the oxidation / diffusion process of manufacture is used for a long time.

When the heat-resistant transparent body according to the present invention is used as the quartz glass substrate 1 of the photomask, since the mark 12 is formed inside the main body 5, high purity, ultra-high flatness and high smoothness are obtained. It is optimal for a substrate of a photomask which is extremely required from the viewpoint of purity, flatness, and smoothness.

Further, accurate positioning can be performed by using an optical device or visually with reference to the mark 12,
It also contributes to improving the productivity of semiconductor manufacturing.

[0042]

EXAMPLES Example 1 Length l: 152 mm, width w: 152 mm, thickness t: 6.3
A flat quartz glass sample 1 having a thickness of 2 mm was manufactured, and the oscillation laser beams 8a and 8b were adjusted and oscillated by the method described with reference to FIG. A clear internal mark 12 having an equilateral triangle at the center and consisting of three lines was obtained at the required internal position.

Example 2 Length l: 152 mm, width w: 152 mm, thickness t: 6.3
A sample 2 of a flat rectangular quartz glass having a thickness of 2 mm was manufactured, and the laser beams 11a and 11b were applied to the surface 6 by the method described with reference to FIG.
At a position in the main body 5 that is 3.2 mm away from the
A focal point 13a of a square flat plate having a side of 2 mm is formed at a position 3 mm away from the center, and a focal point 13b of a laser beam 13b orthogonal to the focal point 13a is formed. Straight line length 2 at the intersection formed by the two focal points 13 and 13b
mm internal mark 12 was obtained.

Example 3 Length l: 152 mm, width w: 152 mm, thickness t: 6.3
6 mm plate-shaped square quartz glass sample 3 was prepared, and as shown in FIG. 6, using only one piece 11a, focusing was performed near a square curved surface, and energy was concentrated to obtain a circular mark having a diameter of 2 mm. .

[0045]

As described above, in the heat-resistant transparent body and the method of manufacturing the same according to the present invention, the mark is formed inside the main body of the heat-resistant transparent body by using a laser beam. There is no problem with the reliability even when the quartz glass furnace core tube used under severe conditions is used for a long time, and when used as a quartz glass substrate for photomasks, purity, flatness, smoothness From the viewpoint of the above, it is possible to perform more accurate positioning based on the mark and to contribute to improvement in the productivity of semiconductor manufacturing.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a quartz glass substrate of a conventional photomask.

FIG. 2 is a perspective view of a conventional furnace core tube.

FIG. 3 is a schematic view showing a heat-resistant transparent body of the present invention and a method for producing the same.

FIG. 4 is a partially cutaway view showing another embodiment of the present invention.

FIG. 5 is a partially cutaway view showing another embodiment of the present invention.

FIG. 6 is a manufacturing process diagram of the heat-resistant transparent body of the present invention.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Notch 3 Colorant 4 Furnace tube 5 Main body 6 Refractory 7 Back surface 8 Side surface 9 Square curved surface 10 Thread chamfered portion 11a Laser beam 11b Laser beam 12 Mark 13a Center line 13b Center line 14a Focus 14b Focus

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H01L 21/205 H01L 21/205

Claims (9)

[Claims] 1. In a heat-resistant transparent body having a heat-resistant and transparent main body and a mark attached to the main body, the mark focuses an oscillation laser beam at a required internal position in the main body and concentrates energy. A heat-resistant transparent body, which is a formed internal mark. 2. A plurality of oscillating laser beams are simultaneously incident at different incident angles so as to focus on a predetermined internal position in a heat-resistant and transparent main body, and the energy density is increased by a superimposing action of the oscillating laser beams. A heat-resistant transparent body, wherein an internal mark is formed in the main body. 3. The heat-resistant transparent body according to claim 1, wherein the heat-resistant and transparent main body is made of quartz glass. 4. The heat-resistant transparent body according to claim 1, wherein the heat-resistant transparent body is a quartz glass substrate of a photomask. 5. The heat-resistant transparent body according to claim 1, wherein the internal mark is an information medium. 6. The heat-resistant transparent body according to claim 1, wherein the internal mark is a bar code. 7. A heat-resistant transparent body, wherein an oscillation laser beam is focused on a required internal position in the body, energy is concentrated, and an internal mark is provided in the body. A method for producing a transparent body. 8. A method in which a plurality of oscillating laser beams are simultaneously incident so as to focus on a required internal position in the main body, an energy density is increased by an overlapping action of the oscillating laser beams, and an internal mark is formed in the main body. The method for producing a heat-resistant transparent body according to claim 7, characterized in that: 9. The method for producing a heat-resistant transparent body according to claim 7, wherein the heat-resistant transparent body is a quartz glass substrate of a photomask.