JP2007290078A - Grinding method of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for grinding the surface of a non-circular shaped substrate with excellent flatness. <P>SOLUTION: In the grinding method for the substrate, the grinding wheel is contacted with the surface of the substrate while rotating the substrate 3 and the grinding wheel 2. The non-circular shaped substrate 3 is used as the substrate, a dummy material 4 is disposed on the peripheral edge part of the non-circular shaped substrate, and the dummy material is disposed so that the grinding wheel always maintains a constant contact area with a surface formed by the non-circular shaped substrate and the dummy material. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a method for grinding a substrate, particularly a method for grinding a surface of a substrate such as a glass substrate.

  A rotary table type vertical shaft surface grinding apparatus is generally used for surface grinding of a circular glass substrate. FIG. 1 shows a schematic diagram of a rotary table type vertical shaft surface grinding apparatus as seen from the side, and FIG. 2 shows a schematic diagram of the rotary table type as viewed from the top. Such a grinding apparatus has a rotary table 1 and a cup-type grinding wheel 2, and a circular glass substrate 3 to be ground is fixed to a central portion on the rotary table 1.

  The cup-type grinding wheel 2 that performs grinding is usually aligned so that the circumferential grinding wheel portion of the cup-type grinding wheel passes through the center of the rotary table. After fixing the circular glass substrate, while rotating the rotary table 1, the cup-type grinding wheel 2 positioned above the rotary table 1 is lowered while being rotated in the direction opposite to the rotation direction of the rotary table 1. The glass substrate surface is ground by bringing 2 into contact with the glass substrate 3 surface.

  When the glass substrate to be ground is circular, as shown in FIG. 3, the area of the contact portion 5 between the glass substrate and the grindstone at the time of grinding is always constant regardless of the rotation state of the glass substrate, Since there is no change in grinding resistance, as shown in FIG. 4, the surface shape of the glass substrate after grinding does not have a shape distribution in the circumferential direction around the center of the rotary table, and is ground flat.

  However, when the substrate to be ground has a non-circular shape, for example, when it is square, the contact area between the substrate and the grindstone during grinding changes as the glass substrate rotates as shown in FIG. Due to the change in the grinding resistance due to, as shown in FIG. 6, the surface shape of the substrate after grinding generates a circumferential shape distribution starting from the center of the rotary table.

  Furthermore, when the substrate to be ground is rectangular, as shown in FIG. 7, the contact area between the substrate and the grindstone at the time of grinding changes more greatly than in the case of a square as the substrate rotates. Thus, in the surface shape of the glass substrate after grinding, the shape distribution in the circumferential direction with the center of the rotary table as a base point is generated more greatly than in the case of a square shape.

  As described above, when the substrate to be ground has a non-circular shape, there is a problem that the surface cannot be ground flat.

For such problems, the glass substrate is ground flat by controlling the cutting amount, which is the amount of descent of the grindstone per unit time, according to the change in the contact area between the glass substrate and the grindstone during grinding. Methods and apparatus have been proposed. (For example, see Patent Document 1)
However, in order to carry out the method, it is necessary to introduce a grinding control mechanism or to modify the grinding apparatus, and when grinding a small amount of glass substrate or grinding various types of glass substrates of different sizes, When a plurality of grinding apparatuses having different rotary table sizes are used, further improvements have been desired, for example, the apparatus becomes complicated.

  An object of the present invention is to provide a method for simply and flatly grinding a surface of a non-circular substrate.

Japanese Patent Laid-Open No. 9-290366

  As a result of intensive studies in view of the above situation, the present inventors have rotated the substrate and grinding wheel while rotating the substrate and bringing the grinding wheel into contact with the substrate surface and grinding the substrate surface. Place a dummy material around a non-circular substrate and grind the surface of the substrate together with the surface of the dummy material so that the area where the grindstone contacts the substrate or the dummy material is constant. The present inventors have found that the surface of a non-circular substrate can be ground and completed the present invention.

  That is, the present invention uses a non-circular substrate as a substrate in a substrate grinding method in which a grindstone is brought into contact with the substrate surface while rotating the substrate and the grindstone, and a dummy material is disposed on the peripheral portion of the non-circular substrate. The dummy material relates to a method for grinding a substrate, wherein the grindstone is arranged so as to always maintain a constant contact area with a surface formed from the non-circular substrate and the dummy material.

  Hereinafter, the present invention will be described in detail.

  In the grinding method of the present invention, a rotary table type vertical axis surface grinding apparatus as described above can be used. However, as shown in FIG. 9, the non-circular substrate 3 and the dummy material 4 to be ground are fixed on the rotary table 1, and the cup-type grindstone 2 for grinding is usually a circumferential shape of a cup-type grindstone. The grinding wheel portion is aligned so as to pass through the center of the rotary table 1.

  As a material of the substrate, any material that is generally used as a substrate material can be used without particular limitation. Examples thereof include glass such as quartz glass, ceramics, silicon, and the like. When the substrate is made of a material such as quartz glass as a grinding object, a metal bond diamond grindstone, a resin bond diamond grindstone or the like is generally used as the grindstone, and the grindstone count is appropriately determined according to the required surface roughness of the substrate. Can be determined.

  As described above, when a non-circular substrate is fixed to the center of the turntable as an object to be ground, the area where the grindstone contacts the substrate during grinding changes with the rotation of the substrate and is not constant. For this reason, if the object to be ground is a non-circular substrate, a dummy material is disposed on the peripheral edge of the substrate, and the substrate and the dummy material are arranged so as to form a circular shape based on the center of the rotary table. The area where the grindstone contacts the substrate and the dummy material at the time of grinding is always constant regardless of the rotation state of the substrate, so that the grinding resistance does not change and the substrate can be ground flat.

  The substrate that can be used in the present invention can be applied to any shape other than a square, a rectangle, a polygon, and the like.

  There are no particular restrictions on the position of the dummy material disposed on the peripheral edge of the substrate in the present invention, as long as the area where the grindstone contacts the substrate and the dummy material during rotation is constant, as shown in FIG. In the case of the square substrate 3, the dummy material 4 may be disposed so as to surround the substrate. As shown in FIG. 11, in the case of the semicircular substrate 3, only a certain direction side with respect to the substrate is provided. The dummy material 4 may be disposed on the surface.

  Further, the number of substrates to be ground in the present invention may be one or a plurality. In the case of a plurality of sheets, as shown in FIG. 12, the dummy material 4 may be arranged and fixed around the plurality of substrates 3 so that the area where the grindstone contacts the substrate and the dummy material during rotation is constant. . In addition, when installing a plurality of substrates, it is preferable to arrange them at intervals so that the side surfaces of the substrates are not damaged by contact between the substrates, so that the substrates are not completely in contact with each other, Although it differs depending on the size of the substrate, specifically, 1 to 10 mm is preferable.

  Furthermore, the number of dummy materials arranged on the peripheral edge of the substrate in the present invention is not particularly limited as long as the area where the grindstone contacts the substrate and the dummy material during rotation is constant, as shown in FIG. In addition, a minimum number of dummy materials 4 having a shape suitable for the substrate 3 to be ground may be disposed, or a plurality of dummy materials having various shapes may be disposed in combination according to the shape of the substrate to be ground. Absent.

  In the present invention, the constant contact area of the grindstone with the substrate and the dummy material during the rotation can grind the substrate with the most flatness, but the rotation can be performed within the allowable processing accuracy range for the flatness. Sometimes, the area where the grindstone contacts the substrate and the dummy material may be made substantially constant.

  The height (thickness) of the dummy material surface from the table surface on the rotary table of the grinding apparatus according to the present invention is preferably the same as the substrate surface height or higher than the substrate surface height.

  If the dummy material surface is lower than the substrate surface, the grinding wheel will contact the substrate, but will not contact the dummy material until the substrate surface height is the same as the dummy material surface height. Only the substrate will be ground. If there is no particular limitation on the thickness of the substrate after grinding, if there is a limitation, the height of the dummy material surface from the table surface is the same as the height of the substrate surface or the height of the substrate surface. Higher is preferred.

  The material of the dummy material arranged around the substrate in the present invention is preferably the same as that of the substrate to be ground, but the material having the same grinding resistance and grinding characteristics as the substrate to be ground. As long as there is a different material, it may be used.

  As a method of fixing the substrate and the dummy material to the turntable in the present invention, vacuum adsorption or wax, gypsum, etc. may be used, and it may be fixed directly to the surface of the turntable. Once the substrate and the dummy material are fixed using wax, gypsum, etc., the pedestal or the substrate may be fixed on the rotary table by vacuum suction or the like.

  In the present invention, when the dummy material is disposed on the peripheral edge of the substrate, the side surface of the dummy material may contact the side surface of the substrate, but the dummy material is not damaged by contact with the dummy material. The material and the substrate are preferably separated so as not to contact each other.

  Although the space | interval of a board | substrate and a dummy material changes with sizes of a board | substrate, 1-10 mm is preferable.

  In the present invention, a dummy material is disposed on the periphery of the non-circular substrate so that the area where the grindstone contacts the substrate and the dummy material during rotation is constant, and the surface of the substrate is ground together with the surface of the dummy material. By doing so, the substrate can be ground with good flatness, and a substrate having a shape other than a circle can be ground with good flatness.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
As a grinding object, a quartz glass substrate having a side length of 200 mm and a thickness of 1 mm was prepared. This glass substrate was fixed to the center of a φ300 silicon wafer using wax. Next, as shown in FIG. 10, four 1 mm-thick dummy materials made of quartz glass were arranged on the periphery of the glass substrate so as to cover the entire surface of the silicon wafer, and similarly fixed with wax. A gap of about 1 mm was left between the glass substrate and the dummy material.

  Next, the silicon wafer on which the glass substrate and the dummy material were fixed was fixed by vacuum suction to a φ300 rotary table of a rotary table type vertical axis surface grinding apparatus. A cup-type metal bond diamond grindstone having a diameter of 450 mm and a grindstone width of 5 mm was used as the grinding wheel, and the circumferential grindstone portion of the cup-type grindstone was aligned so as to pass through the center of the rotary table.

  Next, the rotary table of the grinding device is rotated at 120 rpm, the cup-type grindstone is rotated at 700 rpm in the opposite direction to the rotary table, the cup-type grindstone is lowered, and the grindstone comes into contact with the glass substrate and the surface of the dummy material. While applying water as a grinding liquid, the grindstone was lowered by 60 μm at a descending speed of 6 μm / min, and the surfaces of the glass substrate and the dummy material were ground.

  When the surface shape of the glass substrate after grinding was measured with a stylus type surface shape measuring instrument, as shown in FIG. 14, the shape distribution in the circumferential direction centered on the center of the substrate was about 0.5 μm. As shown in FIG. 4, when the circular glass substrate of φ300 shown in FIG. 4 was ground in the same manner, the shape distribution of the surface shape of the substrate was very good.

Example 2
As a grinding object, a quartz glass substrate having a side length of 260 mm × 150 mm and a thickness of 1 mm was prepared. This glass substrate was fixed to the center of a φ300 silicon wafer using wax. Next, as shown in FIG. 15, four 1 mm-thick dummy materials made of quartz glass were placed around the glass substrate so as to cover the entire surface of the silicon wafer, and similarly fixed with wax. A gap of 5 mm was left between the glass substrate and the dummy material.

  Next, the silicon wafer on which the glass substrate and the dummy material were fixed was similarly fixed to the same apparatus as in Example 1, and the surfaces of the glass substrate and the dummy material were ground under the same conditions as in Example 1.

  When the surface shape of the glass substrate after grinding was measured by a stylus type surface shape measuring instrument, as shown in FIG. 16, the shape distribution in the circumferential direction centered on the center of the substrate was about 0.5 μm. It was very good.

Comparative Example 1
As a grinding object, a quartz glass substrate having a side length of 200 mm and a thickness of 1 mm was prepared. This glass substrate was fixed to the center of a φ300 silicon wafer using wax.

Next, the silicon wafer on which the glass substrate was fixed was similarly fixed to the same apparatus as in Example 1, and the surface of the glass substrate was ground under the same conditions as in Example 1.
When the surface shape of the glass substrate after grinding was measured with a stylus type surface shape measuring instrument, as shown in FIG. 6, the shape distribution in the circumferential direction centered on the center of the substrate was about 1.2 μm. Met.

Comparative Example 2
As a grinding object, a quartz glass substrate having a side length of 260 mm × 150 mm and a thickness of 1 mm was prepared. This glass substrate was fixed to the center of a φ300 silicon wafer using wax.

Next, the silicon wafer on which the glass substrate was fixed was similarly fixed to the same apparatus as in Example 1, and the surface of the glass substrate was ground under the same conditions as in Example 1.
When the surface shape of the glass substrate after grinding was measured with a stylus type surface shape measuring instrument, as shown in FIG. 8, the shape distribution in the circumferential direction centered on the center of the substrate was about 3 μm. It was.

It is the schematic diagram which looked at the conventional rotary table type vertical axis surface grinding apparatus from the side. It is the schematic diagram which looked at the conventional rotary table type vertical axis surface grinding apparatus from the upper surface. It is a figure which shows the contact area of a grindstone and a board | substrate at the time of table rotation at the time of grinding the circular shaped board | substrate in the conventional method. It is a figure which shows the shape of the grinding surface of a circular-shaped board | substrate in the conventional method. It is a figure which shows the contact area of the grindstone and a board | substrate at the time of table rotation at the time of grinding a square-shaped board | substrate in the conventional method. It is a figure which shows the shape of the grinding surface of a square-shaped board | substrate in the conventional method. It is a figure which shows the contact area of the grindstone and a board | substrate at the time of table rotation at the time of grinding the rectangular-shaped board | substrate in the conventional method. It is a figure which shows the shape of the grinding surface of a rectangular-shaped board | substrate in the conventional method. It is the schematic diagram which looked at the rotary table type | formula vertical surface grinding apparatus which can implement the method of this invention from the upper surface. It is a figure which shows the example which has arrange | positioned the dummy material around the square-shaped board | substrate. It is a figure which shows the example which has arrange | positioned the dummy material to the one side of the glass substrate of a semicircle shape. It is a figure which shows the example which has arrange | positioned the dummy material around the some glass substrate. It is a figure which shows the example which has arrange | positioned one dummy material around the glass substrate. It is a figure which shows the shape of the grinding surface of a square-shaped glass substrate in the method of this invention. It is a figure which shows the example which has arrange | positioned the dummy material around the rectangular-shaped glass substrate. It is a figure which shows the shape of the grinding surface of a rectangular-shaped glass substrate in the method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary table 2 Cup type grindstone 3 Substrate 4 Dummy material 5 Contact part of a substrate and a grindstone

Claims (4)

In a method for grinding a substrate in which a grindstone is brought into contact with the substrate surface while rotating the substrate and the grindstone, a non-circular substrate is used as the substrate, and a dummy material is disposed on the peripheral portion of the non-circular substrate. A grinding method for a substrate, wherein the grinding stone is arranged so as to always maintain a constant contact area with a surface formed from a non-circular substrate and a dummy material. 2. The substrate grinding method according to claim 1, wherein the dummy material is the same material as the substrate. 2. The substrate grinding method according to claim 1, wherein the material of the substrate is quartz glass. 4. The substrate grinding method according to claim 2, wherein the dummy material is quartz glass.

Images