JP2002144199A - Surface grinding method and surface grinding machine for sheet disc-like workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform surface grinding with high accuracy and reduce force applied to a wafer by grinding with the micro depth of cut without leaving a grinding streak. SOLUTION: In this surface grinding method for a sheet disc-like workpiece W by grinding one side machined surface of the sheet disc-like workpiece W with the outer peripheral surface of a grinding wheel 7, the workpiece W and the grinding wheel 7 are respectively rotated on their axes, and the grinding wheel 7 is relatively moved in the radial direction of the workpiece W to grind the workpiece W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface grinding method and a surface grinding machine for a thin disk-shaped work, and more particularly, to a surface grinding method for grinding one surface of a thin disk-shaped work such as a semiconductor wafer. And a surface grinder.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No.
There is one described in Japanese Patent No. 128646.

This surface grinder is provided with a grindstone shaft movably provided in the axial direction, an annular grindstone fixed to the grindstone shaft and having an end surface as a grinding surface, and a work surface of a work piece on a grinding surface of the grindstone. There is provided a work rotating means for supporting and rotating the work such that the outer periphery of the work is opposed to the grinding surface of the grindstone and the center of the work is always located within the grinding surface.

According to this grinding machine, the work rotates on its own with the outer periphery of the work intersecting with the outer periphery of the grinding surface and the center of the work is always positioned within the grinding surface. All of the processed surfaces pass between the ground surfaces and come into contact with the ground surfaces, so that the entire processed surface of the workpiece can be ground.

[0005]

In recent years, high precision has been required for surface grinding of semiconductor wafers. However, in the above-mentioned surface grinder, portions other than the vicinity of the center of the work are in contact with the grinding surface only for a part of the time during one rotation of the work, but the vicinity of the center is always in contact with the grinding surface. For this reason, the grinding amount near the center becomes larger than that of other parts, and there is a problem that the center portion is slightly depressed in the ground work. Further, since the time near the center of the work is in contact with the grindstone for a longer time, the grinding mark is not uniformly applied to the entire processing surface of the work, which causes a problem that a grinding streak remains. Furthermore, in the conventional surface grinder, when the number of rotations of the work is increased, the dent at the center becomes large, so that it is necessary to grind the work surface of the work with a small number of rotations, so that the cut amount becomes large, and There is also a problem that such a force increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, perform surface grinding with high accuracy, perform grinding with a small cutting amount without leaving grinding streaks, and apply a force to a work. To provide a surface grinding method and a surface grinding machine for a thin disk-shaped work having a small diameter.

[0007]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the surface grinding method according to the first aspect of the present invention is directed to a method of forming a flat surface of a thin disk-shaped workpiece by a flat surface with an outer peripheral surface of a grinding wheel. In the method of grinding a thin disk-shaped work to be ground, the work and the grindstone are rotated on their own, and the grindstone is relatively moved in the radial direction of the work to perform the grinding.

According to this method, the number of rotations of the grindstone and the work per unit time and the relative moving speed of the grindstone and the work are controlled so that the contact time between the grindstone and the work is the same on all the processing surfaces of the work. Since the grinding wheel contact time in a specific portion of the work does not become long, the surface grinding can be performed with high accuracy. In addition, the entire processing surface of the work can be uniformly ground, and no grinding streaks remain. Further, since the grinding is performed during a plurality of rotations of the work, the grinding can be performed with a small cutting amount, and the force applied to the work is reduced. Further, since the force applied to the work is reduced, the relative movement speed can be increased to shorten the work grinding time.

It is preferable that the grindstone and the work be moved relative to each other until the grindstone traverses or vertically crosses the work when viewed relatively. In addition, a columnar or truncated cone is used as the grindstone.

[0010] In particular, in the above method, the axis of the grindstone is inclined with respect to the moving direction and the axis of the grindstone and the workpiece are viewed from a direction perpendicular to the work surface of the workpiece. It is preferable to perform the grinding so that the center locus intersects. That is, it is preferable that the axis of the grindstone and the relative movement direction are not the same or perpendicular to each other.

In this way, all parts of the work can be machined even if the positional relationship between the grindstone and the work slightly shifts.

The reason will be described with reference to FIG. In the following description, the same reference numerals are used for the grindstone and the work as those used in the description of the embodiment described later.

As shown in FIG. 3 (b), when the direction of the axis of the grindstone (7) is the same as the moving direction of the work (W), the grinding process is indicated by a broken line c in FIG. 3 (b). It is performed in the part where the grinding wheel (7) and the work (W) are in contact, but the work (W)
If the movement trajectory of the center does not coincide with the axis of the grindstone (7), for example, if there is a shift indicated by a in FIG. 3 (b), a circular non-ground portion having a radius a is located at the center of the work (W). b occurs. That is,
The inside of the circle b does not cross the broken line c even if the grindstone (7) moves in the left-right direction, and the inside of the circle b cannot be ground.

On the other hand, as shown in FIG. 3 (a), when the axial direction of the grindstone (7) is inclined with respect to the moving direction, the work (W) is moved within the range indicated by e in FIG. 3 (a). If the movement locus at the center of ()) is made to pass, all the portions on the processing surface of the work (W) cross the broken line d with the movement of the grindstone (7), and there is no portion where grinding is not performed.

Further, the surface grinding machine of the present invention is a surface grinding machine for a thin disk-shaped work provided with a grindstone for grinding one side processed surface of the thin disk-shaped work on an outer peripheral surface, and rotates the grinding wheel on its own. It is characterized by comprising a grindstone rotating means, a work rotating means for rotating the work, and a moving means for relatively moving the grindstone in the radial direction of the work.

According to this grinding machine, the method described in claim 1 can be easily performed.

In particular, in the above grinding machine, when viewed from a direction perpendicular to the work surface of the work,
Preferably, the grindstone is arranged such that the axis of the grindstone is inclined and the axis of the grindstone intersects with the movement locus of the center of the workpiece, so that the method according to claim 2 can be easily implemented. Can be.

It is preferable that the relative speed defined by the rotational speed of the work, the rotational speed of the grindstone, and the feed speed is increased as the distance from the outer periphery of the work to the center of the work is increased. That is, it is preferable that the relative speed at the center of the work be the highest.

This makes it possible to make the finished surface roughness constant.

This is realized, for example, by increasing the number of revolutions of the work as the grindstone approaches the center of the work, or increasing the number of revolutions of the grindstone. Further, the feed speed may be increased as approaching the center of the work.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a single-sided surface grinder according to a first embodiment of the present invention. In the following description, front, rear, left and right refer to FIG.
In FIG. 1, the front side of the paper is referred to as front, the back side of the paper is referred to as rear, and the left in FIG. That is, in FIG. 2, the upper side is rear and the lower side is front.

The grinding machine (1) is a horizontal bed (2), a bed
A moving table (3) attached to (2) movably in the left-right direction, a thin disk-shaped work provided on the moving table (3) so as to be movable up and down and to rotate around a vertical axis
A rotary table (4) on which (W) is placed horizontally, and a grinding wheel head (5) arranged on the left side of the bed (2).

The grinding wheel head (5) has an upper portion projecting forward when viewed from the side, and the rotary table (4) and the moving table (3) can pass below the projecting portion (5a). . Then, a horizontal grinding wheel shaft (6) extends rightward and slightly backward from the protruding portion (5a), and the grinding wheel shaft (6)
A whetstone (7) is attached to the tip of.

The configuration for moving the moving table (3), the configuration for rotating the rotary table (4), and the configuration for moving the rotary table (4) up and down are all known. The detailed description is omitted. Further, a suitable known drive device (not shown) for rotating the grindstone shaft (6) is arranged in the grindstone head (5).

In this grinding machine (1), since the grinding wheel shaft (6) extends slightly rearward, as shown in FIG.
The axis of the grindstone (7) is inclined in the left-right direction, that is, the moving direction of the work. In the case of the grinding machine (1), as the grindstone (7), a combined grindstone having a different roughness between the right peripheral part (7a) and the left peripheral part (7b) is used, and the right peripheral part (7a) is used. Roughing is performed, and finishing is performed on the left side portion (7b) of the peripheral surface, so that the force applied to the work (W) at the initial stage of processing is reduced. In order to reduce the force applied to the work (W) at the beginning of processing, a truncated conical grindstone having a small diameter on the right side may be used.

In the grinding machine (1) having the above configuration, the positions of the grindstone (7) and the rotary table (4) are adjusted, and after setting the cutting amount and the like for the work (W) to predetermined values. The work (W) is placed on the rotary table (4).
Thereafter, as shown in FIG. 2, by rotating the work (W) and the grindstone (7) while rotating the rotary table (4) from right to left, the grindstone (7) relatively moves the work (W). Work across
Surface grinding is performed by the outer peripheral surface of the grinding wheel (7) of (W). When performing machining, it is necessary to make the roughness of the finished surface of the machined surface of the work (W) constant on all the machined surfaces. Therefore, when the grindstone (7) is located on the outer periphery of the work (W) and when the grindstone (7)
It is preferable to change the feed speed of the work (W) with respect to the grindstone (7), that is, to change the moving speed of the moving table (3) when the object is located at the center of the work (W). Specifically, the moving speed of the moving table (3) is adjusted such that the feeding speed at the center is high and the feeding speed at the outer circumference is low. It should be noted that the ground surface roughness can also be made constant by making the feed speed of the moving table (3) constant and changing the rotation speed of the work (W). Further, the roughness of the finished surface can be made constant by changing the rotation speed of the grinding wheel (7). Alternatively, all the speeds may be changed to make the finished surface roughness constant.

If the grindstone (7) is arranged such that the axis of the grindstone (7) is inclined with respect to the left-right direction (moving direction) as in the above-mentioned grinder, the axis of the grindstone (7) and the work (W) When the positional relationship between the grindstone (7) and the work (W) is adjusted so that the movement locus of the center of the work (W) intersects, all of the processed surface of the work (W) can be ground.

For example, if the axis of the grindstone (7) is inclined with respect to the moving direction of the work (W), the movement locus of the center of the work (W) moves within the range indicated by e in FIG. If it passes, the grinding process is performed on all the parts of the work (W). In other words, when determining the position of the work (W) with respect to the grindstone (7), a deviation of e / 2 is allowed in the front-rear direction, so that a high precision is required for adjusting the positional relationship between the grindstone (7) and the work (W). Not required.

On the other hand, when the axis of the grindstone (7) extends in the same direction as the moving direction of the work (W), the axis of the grindstone (7) is
If it does not pass through the center of the work (W), there will be a part where grinding is not performed.To perform grinding in all parts of the work (W), the axis of the grindstone (7) must pass through the center of the work (W). The positional relationship between the grindstone (7) and the work (W) must be adjusted, and high accuracy is required to adjust the positional relationship.

It should be noted that the configuration of the present invention is not limited to the above embodiment, and various modifications are possible. For example, the work (W) may be supported at its edge by a plurality of rollers.

[Brief description of the drawings]

FIG. 1 is a front view of a surface grinder according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a main part of the surface grinding machine.

FIG. 3A is a plan view illustrating an arrangement relationship between a grindstone and a work, and FIG. 3B is a plan view illustrating another arrangement relationship between a grindstone and a work.

[Explanation of symbols]

 (1) Grinding machine (2) Bed (3) Moving table (moving means) (4) Rotary table (work rotating means) (7) Whetstone (W) Work

Claims (4)

[Claims] 1. A method for surface grinding a thin disk-shaped work, wherein one side of a thin disk-shaped work is surface-ground by an outer peripheral surface of a grinding wheel. A grinding method for a thin disk-shaped workpiece, wherein the grinding is performed by relatively moving the workpiece. 2. When viewed from a direction perpendicular to the work surface of the workpiece,
The flat surface of the thin disk-shaped workpiece according to claim 1, wherein the grinding is performed such that the axis of the grinding stone is inclined with respect to the moving direction and the axis of the grinding stone and the movement locus of the center of the workpiece intersect. Grinding method. 3. A surface grinding machine for a thin disk-shaped work provided with a grindstone for surface-grinding the one-side processing surface of the thin disk-shaped work on an outer peripheral surface, comprising: a grinding wheel rotating means for rotating the grinding wheel; A surface grinding machine for a thin disk-shaped work, comprising: a work rotating means for rotating the work; and a moving means for relatively moving the grindstone in a radial direction of the work. 4. When viewed from a direction perpendicular to the work surface of the work,
4. The thin plate circle according to claim 3, wherein the grindstone is arranged such that the axis of the grindstone is inclined with respect to the moving direction of the work, and the axis of the grindstone and the movement locus of the center of the work intersect. Surface grinding machine for plate-like work.