JP2002307303A - Both face grinding method for thin plate disclike workpiece and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a workpiece having a high degree of flatness without bending during grinding. SOLUTION: This both face grinding device for the thin plate disclike workpiece is provided with a pair of grinding wheels 2A, 2B rotated and arranged in such a way that circular grinding faces on end faces oppose mutually and can move relatively in the axial direction, a workpiece rotation means 3 rotating and supporting both face machining faces of the workpiece W between grinding faces of the grinding wheels 2A and 2B in such a way that both face machining faces of the thin plate disclike workpiece W oppose to the grinding faces of a pair of grinding wheels 2A, 2B, respectively, bending detection means 6A, 6B for detecting bending of the workpiece W from a flat condition, and a control means for controlling positions of the grinding wheels 2A, 2B based on the bending of 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 method and an apparatus for grinding both sides of a thin disk-shaped work, and more particularly to a method and apparatus for simultaneously grinding both sides of a thin disk-shaped work such as a semiconductor wafer. More specifically, the present invention relates to a method and an apparatus suitable for grinding a plurality of thin disk-shaped works one by one and continuously, and particularly suitable for a large-diameter thin work.

[0002]

2. Description of the Related Art As a conventional double-side grinding method for a thin disk-shaped work of this type, there is a method described in Japanese Patent Application Laid-Open No. H11-198008.

[0003] In this grinding method, a workpiece is held between a pair of cup-shaped grinding wheels, which are arranged so that annular grinding surfaces face each other and are relatively movable in an axial direction and are rotated, and the outer periphery of the workpiece is ground to the grinding wheel. Arrange so that the outer circumference of the grinding surface intersects and the center of the work is located in the grinding surface, support the part of the work that is outside from between the grinding wheels and rotate the work, and rotate the grinding wheel. This is a method in which a thin disk-shaped workpiece is ground while both sides of the thin disk-shaped workpiece are sandwiched between whetstones by rotating in the axial direction while rotating, and the sensor is moved in the diameter direction of the workpiece to measure the thickness of the workpiece, and this measurement result The parallelism of the workpiece is increased by adjusting the inclination of the grindstone based on the above.

[0004]

The above-mentioned method aims to obtain a work having a uniform thickness by obtaining a work having a uniform thickness and a ground work having a high degree of parallelism.

[0005] By the way, a pair of grinding wheels for performing double-side grinding has a difference in abrasion amount due to a slight difference in grinding conditions between the grinding surfaces of the respective grinding wheels during grinding, and the position of the grinding surface gradually becomes desired. It deviates from the state. As in the conventional method described above, when a portion of a work that is outside from between grinding wheels is supported, and a portion of an unsupported work is sandwiched and ground by a grindstone, the position of the grinding surface is changed from a desired position. If grinding is performed in a misaligned state, either one of the grindstones will hit the work first, and the grinding will be performed with the work bent, and the work after grinding will bend and the flatness of the work will be reduced. There is.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for grinding a thin disk-shaped work capable of obtaining a work having a high degree of flatness without bending the work during grinding. Aim.

[0007]

Means for Solving the Problems and Effects of the Invention In order to solve the above-mentioned problems, a method for grinding a thin disk-shaped work according to the present invention grinds a plurality of thin disk-shaped works one by one and continuously. In the method of double-sided grinding of a thin disk-shaped work, between a pair of grinding wheels that are arranged and rotated so that the circular grinding surfaces are opposed to each other and are relatively movable in the axial direction, the processing surfaces on both surfaces of the work are The work surfaces are supported so as to face the grinding surfaces of the pair of grinding wheels, and the grinding wheels are relatively rotated in the axial direction while rotating, thereby grinding both surfaces of the workpiece in a state where the workpiece is sandwiched by the grinding wheels. A step of determining an optimum position of a grinding wheel grinding surface at the time of completion of the grinding wheel cutting, in which the workpiece after grinding is flat without bending, and detecting a bending amount at the completion of the grinding wheel cutting of each work. You And a step of adjusting the position of the grindstone so that the position of the grinding surface at the time of completion of grinding of the next work becomes the optimum position when the bending amount of each work exceeds a predetermined amount. It is.

According to this method, the bending of each work at the end of grinding is suppressed to a predetermined amount or less, and the work can be ground with high parallelism and flatness.

In the above method, preferably, the work is arranged so that the outer periphery of the work and the outer periphery of the grinding surface of the grindstone intersect and the center of the work is located within the grinding surface, and the work is moved out from between the grinding wheels. It supports the part of the work that is in place and rotates the work.

Further, as a double-sided grinding apparatus for a thin disk-shaped work according to the present invention, a pair of grinding wheels arranged and rotated so that the circular grinding surfaces of the end surfaces face each other and are relatively movable in the axial direction. A grinding wheel, a workpiece rotating means for supporting the workpiece between the grinding surfaces and rotating the workpiece so that the processing surfaces on both surfaces of the thin disk-shaped workpiece face the grinding surfaces of the pair of grinding wheels, Some include a bend detecting unit that detects a bend of the work from the state, and a control unit that controls the position of the grindstone based on the bend of the work.

According to this apparatus, the above method can be easily performed. The grinding wheel preferably has a cup shape, and in this case, the annular end surface on the open side is a grinding surface.

It is preferable that the control means stores an optimum position at the time of completion of the cutting of the grinding wheel on the circular grinding surface which becomes flat without bending of the workpiece after the grinding, and controls the grinding wheel based on the optimum position. .

Preferably, in the above apparatus, the work is arranged such that the outer periphery of the work and the outer periphery of the grinding surface of the grindstone intersect and the center of the work is located within the grinding surface. Axial support means for supporting a part of the work that is out of the work, and radial support means for supporting and rotating the work in the radial direction.

In the above apparatus, the axial support means may include a static pressure support member for supporting the work in a non-contact manner by static pressure.

It is preferable to use a so-called pneumatic micrometer as the bend detecting means. As a pneumatic micrometer, a nozzle for spraying fluid onto the work surface of the work is fixedly provided near the outer periphery of the grinding wheel, and the distance between the nozzle and the work surface of the work changes by bending the work from a flat state. It is preferable to use a device that detects the bending of the work by the change in the pressure of the nozzle caused by the change.

Further, as the bending detecting means, a means for detecting the bending of the work by detecting a pressure change in a static pressure pocket provided in the static pressure supporting member may be used.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an apparatus and a method for double-sided grinding of a thin disk-shaped work according to the present invention will be described with reference to FIGS. In the following description, the front, rear, left and right are based on FIG. 1, the left and right in FIG. 1A are left and right, the left in FIG. 1B is front and the right is rear.

FIG. 1 shows a main part of the grinding apparatus (1). The grinding device (1) has a pair of left and right cup-shaped grinding wheels (2A) (2B) that are arranged and rotated so that the annular grinding surfaces of the end surfaces can face each other and move in the left-right direction, and a thin disk-shaped A work rotation device (3) for supporting and rotating the work (W) such that the left and right processed surfaces of the work (W) face the ground surfaces of the left and right grinding wheels (2A) and (2B), respectively.

The grinding wheels (2A) and (2B) extend in the left-right direction, and are arranged such that the axes of both grinding wheels (2A) and (2B) are located on the same straight line. Although not shown, a grindstone axial moving device for moving the grindstones (2A) (2B) in the left-right direction and a grindstone rotating device for rotating the grindstones (2A) (2B) around their axes are provided. The outer periphery of the work (W) is a grinding wheel (2A) (2
It is supported so that it intersects with the grinding surface of B) and its center is located within the grinding surface, and the grinding surface grinds the entire processing surface of the work (W).

In the work rotating device (3), the work (W) is provided such that the outer periphery of the work (W) intersects with the outer periphery of the grinding surface of the grindstones (2A) (2B) and the center of the work (W) is a grindstone. (2A) It arrange | positions so that it may be located in an annular grinding surface of (2B). And the rotation device (3)
In order to support the part of the work (W) protruding from between the grinding wheels (2A) (2B), a notch is provided to avoid interference with the grinding wheels (2A) (2B) A pair of left and right thick plate-shaped fluid supply members for static pressure support of the work (axial support means) (4
A) (4B), a carrier (P) in which a work (W) is fitted in a center hole (Pa), and a known work rotating means (radial support means) (for example, an edge of a carrier (P)). A roller which is in contact with a part and is rotationally driven by an appropriate driving device).

The fluid supply members (4A) and (4B) are publicly known, and a static pressure groove (7) is formed on a surface facing the supply members (4A) and (4B). The static pressure groove (7) is connected to a fluid supply device (not shown) through an air supply hole (8),
The work (W) is held at a static pressure by a fluid such as water spouted from (7).

Two nozzles (6A) and (6B) are formed near the grindstones (2A) and (2B) of the fluid supply members (4A) and (4B), respectively. The nozzles (6A) and (6B) are connected to an air supply source (S) via a known A / E converter (air pressure / electric signal converter) (C). Further, the A / E converter (C) is connected to the pressure detection device (D). The left nozzle (6A) detects the bending of the work (W) by measuring the distance between the left processing surface of the work (W) held by the work rotating device (3) and the left supply member (4A). The right nozzle (6B) measures the distance between the right processing surface of the work (W) held by the work rotation device (3) and the right supply member (4B) to bend the work (W). It is for detecting. That is, the pressure at the outlets of the nozzles (6A) (6B) is proportional to the distance. Nozzle (6A) (6B) outlet pressure is A / E
It is sent to the converter (C). Then, the converted electric signal is A
It is sent from the / E converter (C) to the pressure detector (D). In this way, the nozzle (6A) (6B)
(6A) The distance between (6B) and the work (W) is measured. Then, the measured distance is sent to a suitable known control device (not shown), and the control device controls the grinding wheels (2A) and (2B) as described later. During control, two right nozzles (6B) were used as the distance between the right processing surface of the work (W) and the right supply member (4B).
The average value of the distance between the two left nozzles (6A) and the work (W) is used as the distance between the left processing surface of the work (W) and the left supply member (4A). The average value is used.

In the grinding device (1), the work (W) is ground as follows. At the standby position where the distance between the grindstones (2A) and (2B) is larger than the thickness of the work (W), the grindstones (2A) and (2B)
The work (W) is supported by the rotation device (3) in a state where is positioned. Then, the roller (5) is rotated to rotate the work (W), and the distance between the grindstones (2A) (2B) is reduced so that the grindstones (2A) (2
B) moves in the left-right direction and rotates, and the grinding surface of the grindstones (2A) and (2B) hits the workpiece (W) to start grinding. Then, the grindstones (2A) and (2B) reach the grindstone cutting completion position, and the work (W) is subjected to spark-out grinding. When the spark-out grinding of the work (W) is completed, the grindstones (2A) and (2B) move so as to increase the distance between the grindstones (2A) and (2B), and the grindstones (2A) and (2B) reach the standby position. During this time, the work (W) is taken out of the rotation device (3). This procedure is repeated to grind a plurality of works one by one and continuously.

In performing grinding, the grinding wheel cutting completion position is controlled as described below, and the amount of bending of the work (W) is reduced to a predetermined amount or less. First, the optimum position of the grinding surface of the grindstones (2A) and (2B) at which the bend amount of the work (W) becomes 0 at the completion of the grindstone cutting is determined. The standby position of the grindstone (2) is adjusted based on the optimum position and the bending amount of each workpiece (W) after the grinding is completed, and the grinding wheel cutting completion position of the grinding surface of the grindstones (2A) (2B) is adjusted to the optimum position. From a predetermined amount.

The optimum position is determined as follows.
Prepare multiple workpieces (W). Next, each work (W) is ground experimentally, and each work (W) is nozzle-ized (6A) (6B).
The distance between the left processing surface and the left supply member (4A) and the distance between the right processing surface and the right supply member (4A) are measured. Then, the work (W) after the grinding is taken out from the grinding device (1), and the bending and thickness of the work (W) are measured by a suitable measuring device. Based on the measurement result, the standby position is changed so that the work (W) is no longer bent, and the next work (W) is ground. This is repeated several times to obtain a workpiece (W) having almost zero bend and a predetermined thickness. This is called an ideal work, and is hereinafter indicated by a symbol (W0). Left work surface and left supply member (4A) of work (W0) when ideal work (W0) is obtained
And the distance between the right processing surface and the right supply member (4A) are called ideal distances. Hereinafter, the ideal distances are indicated by symbols (La) and (Lb). Thus, when grinding is completed, the work (W) and the supply member (4A)
The grinding wheel cutting completion position where the distance to (4B) is the ideal distance (La) (Lb) is the optimum position. The ideal distances (La) and (Lb) are stored in the control device.

When the grinding wheels (4A) and (4B) are at the optimum positions when the grinding wheel cut is completed and the distance between the workpiece (W) and the supply members (4A) and (4B) is the ideal distance (La) (Lb), the grinding wheel This means that there is almost no bending of the work (W) when the cutting is completed. On the other hand, when the grinding wheel cut is completed, the grinding wheels (4A) and (4B) are not
If the distance between the supply member (4A) and the supply member (4B) deviates from the ideal distance, it means that the workpiece (W) is bent.

After the optimal position is determined, the first work
Before grinding (W), each grindstone (2A) (2B) is located at the optimal standby position moved in the axial direction by a predetermined distance from the optimal position,
From this state, grinding of the first work (W) is started.

In the initial state, the wear of the grindstones (2A) and (2B) is very small, and there is no or very little deviation between the cutting completion position and the optimum position. Therefore, the work (W) and the supply member (4
The distance between (A) and (4B) is almost equal to the ideal distance (La) (Lb).
The bending of (W) is equal to or less than a predetermined amount, and both the parallelism and the flatness are high.

When the machining of several workpieces (W) is completed, the abrasion of the grindstone (2) progresses, and the deviation between the cutting completion position of the grinding surface of the grindstones (2A) and (2B) and the optimum position increases. The bending amount of the work (W) exceeds a predetermined amount. In FIG. 3, a workpiece whose bending amount exceeds a predetermined amount is indicated by a symbol (W1).

When the bend amount of the work (W) exceeds a predetermined amount, the standby position of the grindstones (2A) and (2B) is set so that the grinding surface of the grindstones (2A) and (2B) is located at the optimum position when the cutting of the grindstone is completed. Has been changed,
The bending amount of the work (W) is made equal to or less than a predetermined amount.

Whether the bending amount of the work (W) exceeds a predetermined amount depends on the difference between the ideal distance (La) and the distance (La ') shown in FIG. 3 and the ideal distance (Lb) and the distance shown in FIG. (Lb ') and the sum of the absolute values of these two differences. That is, when the sum of the absolute values is larger than a predetermined value, it is determined that the bending amount exceeds the predetermined amount, and the grinding stone (2A) (2B)
Is changed so that the grindstones (2A) and (2B) are located at the optimum positions when the cutting is completed. The predetermined amount is set so that the amount of bending of the work (W) does not exceed the allowable bending amount. Adjustment of the standby position of the grindstones (2A) (2B) is performed by the supply members (4A) (4B)
Is performed on the basis of In the case of this embodiment, the adjustment is automatically performed by the control device, but may be performed manually.

The wear of the whetstones (2A) and (2B) progressed, and the whetstones (2A) and (2B)
When replacing B) with a new one, usually a new whetstone (2A)
After the grinding surface of (2B) is positioned at the optimum position, the processing may be restarted after being moved in the axial direction by a predetermined amount and positioned at the ideal standby position. However, if necessary, a new grinding wheel (2A)
The optimal position of (2B) may be determined again.

The nozzles (6A) and (6B) are preferably provided as close as possible to the work surface of the work (W) in order to accurately detect a slight bending of the work (W). Also, it is preferable to provide it at a place as close as possible to the grinding stone on the outer periphery of the grinding stone.

The configuration of the grinding apparatus of the present invention is not limited to the above. For example, the nozzle may be provided on at least one of the left and right sides of the work. If a plurality of nozzles are provided on both sides of the work, the detection accuracy can be improved. Further, a nozzle may be provided separately from the fluid supply member. Also,
Instead of air, a liquid such as a coolant liquid may be ejected from the nozzle, and the pressure at the nozzle outlet may be measured by, for example, a high-sensitivity pressure sensor. Furthermore, in the above embodiment, a static pressure groove for supporting the work (W) and a nozzle for detecting bending are provided separately.
Without a nozzle, instead of static pressure grooves, multiple static pressure pockets are provided, and among these static pressure pockets, the bending of the work (W) can be detected by the change in the pressure of the static pressure pocket closest to the outer periphery of the grindstone. The rotation means can hold the work by the static pressure of the fluid as described above, for example,
The work may be held by a plurality of pairs of rollers that sandwich the work from the processing surface side. In this case, the nozzle may be fixedly provided at an appropriate position.

Further, a laser sensor or the like may be used instead of the nozzle.
The bending of the work may be detected by another detecting means.

Further, the present invention can be applied to both cases where both grinding wheels are fed and where only one grinding wheel is fed. In addition, the present invention can be applied to both a vertical double-sided surface grinder and a horizontal double-sided surface grinder.

[Brief description of the drawings]

FIG. 1 shows a double-sided grinding apparatus for a thin disk-shaped work according to the present invention.
It is a schematic diagram of an embodiment.

FIG. 2 is a diagram illustrating a relationship between a grindstone at an optimum position and a workpiece ground in an ideal state;

FIG. 3 is a diagram illustrating a relationship between a grindstone at a position deviated from an optimum position and a workpiece ground in a state deviated from an ideal state;

[Explanation of symbols]

 (1) Grinding equipment (2A) (2B) Grinding wheel (3) Work rotation means (6A) (6B) Bend detection means (nozzle) (W) Thin disk work

Claims (7)

[Claims] 1. In a method of double-sided grinding of a thin disk-shaped work for grinding a plurality of thin disk-shaped works one by one and continuously, the circular ground surfaces are opposed to each other and can relatively move in the axial direction. Between a pair of grinding wheels that are arranged and rotated in such a manner, the processing surfaces on both surfaces of the work are supported such that the processing surfaces face the grinding surfaces of the pair of grinding wheels, respectively, and the shaft is rotated while rotating the grinding wheels. This method grinds both surfaces of the work while the work is sandwiched by the grindstones by relatively moving in the direction, and the work surface after the grinding is finished is flat without any bending. Determining the optimal position of the workpiece, detecting the amount of bending at the time of completion of the grinding of each workpiece, and, when the bending of each workpiece exceeds a predetermined amount, at the time of completing the grinding of the next workpiece. Adjusting the position of the grindstone so that the position of the grinding surface becomes the optimum position. 2. The work according to claim 1, wherein the work is arranged such that an outer periphery of the work intersects with an outer periphery of a grinding surface of the grindstone and a center of the work is located within the grinding surface. 2. The method according to claim 1, further comprising: supporting the portion and rotating the work.
The double-sided grinding method of the thin disk-shaped work described in the above. 3. A pair of grinding wheels, which are arranged so that the circular grinding surfaces of the end surfaces face each other and are relatively movable in the axial direction and are rotated, and the processing surfaces of both surfaces of the thin disk-shaped work are provided. A work rotation means for supporting the work surfaces on both sides of the work between the grinding surfaces so as to face the grinding surfaces of the pair of grinding wheels, respectively, and detecting a bending of the work from a flat state; A double-sided grinding machine for a thin disk-shaped work, comprising: a bend detecting means; and a control means for controlling the position of the grindstone based on the bend of the work. 4. The work is arranged such that the outer periphery of the work and the outer periphery of the grinding surface of the grindstone intersect and the center of the work is located within the grinding surface, and the work rotating means is moved out from between the grinding wheels. 4. The thin disk-shaped workpiece according to claim 3, further comprising: an axial supporting means for supporting a portion of the projecting workpiece; and a radial supporting means for supporting and rotating the workpiece in a radial direction. Double-side grinding machine. 5. A double-sided grinding apparatus for a thin disk-shaped work according to claim 3, wherein the axial support means includes a static pressure support member for supporting the work in a non-contact manner by static pressure. 6. The double-side grinding apparatus for a thin disk-shaped work according to claim 3, wherein the bending detecting means is a pneumatic micrometer. 7. The thin disk-shaped workpiece according to claim 5, wherein the bending detecting means detects the bending of the workpiece by detecting a pressure change of a static pressure pocket provided in the static pressure supporting member. Double-sided grinding machine.