JP2021167031A - Grinding device - Google Patents

Abstract

To provide a grinding device that can register an origin position more correctly and more safely while reducing burden on an operator.SOLUTION: An origin position setting unit 50 of a grinding device 1 has a control unit 51 that sets an origin position based on signals from a position detection unit 35 that detects the position of a grinding unit 20 elevated/lowered by an elevating/lowering unit 30 and an internal pressure detection unit 48 that detects a cylinder internal pressure of a balance cylinder 40. The control unit 51 controls the elevating/lowering unit 30 to lower a grinding wheel 26 to a chuck table 10, and sets, as the origin position, a position of the grinding unit 20 detected by the position detection unit 35 at a time point when a change in cylinder internal pressure of the balance cylinder 40 that occurs when the grinding wheel 26 contacts a holding surface 11 of the chuck table 10 or a contact surface having a predetermined height relation with the holding surface 11.SELECTED DRAWING: Figure 1

Description

The present invention relates to a grinding device.

A grinding device for grinding a plate-shaped workpiece such as a wafer of a semiconductor device with a grinding wheel to thin it is known. The grinding device is provided with a spindle having a rotation axis perpendicular to the holding surface of the chuck table that holds the workpiece, and a grinding wheel in which the grinding wheel is arranged in an annular shape on the lower surface is attached to the lower end of the spindle to cover the grinding wheel. The workpiece is ground by contacting it with the workpiece (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-2538337

In the grinding device, the height at which the lower end of the grinding wheel and the holding surface come into contact is registered as the origin position, and the spindle (grinding unit) on which the grinding wheel is mounted is controlled to move up and down. , The grinding unit was lowered toward a clearance gauge having a predetermined thickness placed on the holding surface, and the origin position was registered with reference to the position where the grinding wheel came into contact with the clearance gauge. However, there is a problem that the work of checking the gap between the grinding wheel and the feeler gauge while raising and lowering the grinding unit is a work that requires the operator's skill, which is a burden on the operator.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a grinding device capable of registering an origin position more accurately and safely while reducing the burden on an operator.

In order to solve the above-mentioned problems and achieve the object, the grinding device of the present invention has a chuck table for holding the workpiece on the holding surface and a spindle having a rotation axis perpendicular to the holding surface. A grinding unit that grinds the workpiece held on the chuck table with a grinding wheel mounted on the lower end, an elevating unit that raises and lowers the grinding unit in a direction perpendicular to the holding surface, and the grinding unit of the grinding unit. A grinding device including a balance cylinder that lifts with a force corresponding to the weight and an origin position setting portion that sets the origin position of the grinding wheel with respect to the chuck table, and the origin position setting portion is raised and lowered by the elevating unit. The control unit has a position detection unit that detects the position of the grinding unit and a control unit that sets the origin position based on a signal from the internal pressure detection unit that detects the cylinder internal pressure of the balance cylinder. Is generated when the grinding wheel is lowered to the chuck table by the elevating unit and the grinding wheel comes into contact with the holding surface of the chuck table or a contact surface having a predetermined height relationship with the holding surface. It is characterized in that the position of the grinding unit detected by the position detecting unit at the time when the change in the cylinder internal pressure of the balance cylinder is detected is set as the origin position.

INDUSTRIAL APPLICABILITY The present invention can register the origin position more accurately and safely while reducing the burden on the operator.

FIG. 1 is a side sectional view showing a configuration example of the grinding apparatus according to the embodiment. FIG. 2 is a side sectional view of a main part of the grinding device of FIG. FIG. 3 is a cross-sectional view showing a balance cylinder of the grinding device of FIG. FIG. 4 is a flowchart showing an example of a processing procedure for the operation of the grinding apparatus of FIG. FIG. 5 is a graph showing an example of a change in the cylinder internal pressure of the balance cylinder detected by the grinding apparatus of FIG.

An embodiment (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Further, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions or changes of the configuration can be made without departing from the gist of the present invention.

[Embodiment]
The grinding apparatus 1 according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a configuration example of the grinding device 1 according to the embodiment. FIG. 2 is a side sectional view of a main part of the grinding device 1 of FIG. FIG. 3 is a cross-sectional view showing the balance cylinder 40 of the grinding device 1 of FIG. As shown in FIG. 1, the grinding device 1 includes a chuck table 10, a grinding unit 20, an elevating unit 30, a balance cylinder 40, and an origin position setting unit 50. The grinding device 1 grinds the workpiece 100 held by the chuck table 10 with the grinding unit 20.

The workpiece 100 to be ground by the grinding device 1 is, for example, a wafer such as a disk-shaped semiconductor wafer or an optical device wafer whose base material is silicon, sapphire, gallium arsenide, or the like. In the workpiece 100, for example, a device such as a semiconductor device is formed in a region defined by a plurality of scheduled division lines formed in a grid pattern on a flat surface, and the workpiece 100 is ground from the back surface side opposite to the front surface. Will be done. Further, in the present invention, the workpiece 100 may be a rectangular package substrate, a ceramic plate, a glass plate or the like having a plurality of devices sealed with resin.

As shown in FIG. 1, the chuck table 10 has a holding surface 11 that is parallel to the horizontal plane and faces upward. A suction source (not shown) is connected to the chuck table 10, and the surface side of the workpiece 100 is suction-held by the holding surface 11 by the negative pressure supplied from the suction source. A rotation drive unit (not shown) is connected to the chuck table 10, and the chuck table 10 can rotate around the Z axis by the rotation drive unit.

As shown in FIG. 1, the grinding unit 20 includes a spindle 21 and a grinding wheel 22. The grinding wheel 22 includes an annular base 25 mounted on the lower end of the spindle 21 and a plurality of grinding wheels 26 fixed to the base 25 and arranged in an annular shape. The grinding unit 20 rotates the grinding wheel 22 around the Z-axis by the spindle 21 and presses the workpiece 100 held by the holding surface 11 of the chuck table 10 along the Z-axis direction to press the workpiece 100. Grind 100. In the present embodiment, the grinding unit 20 has a large weight, for example, about 30 kg.

The elevating unit 30 is mounted on one side surface of the grinding unit 20 (+ Y direction in FIG. 1), and elevates and elevates the grinding unit 20 in the vertical direction (Z-axis direction) which is a direction substantially perpendicular to the holding surface 11 of the chuck table 10. Let me. The elevating unit 30 grinds and feeds the grinding unit 20 in the vertical direction.

Further, as shown in FIG. 1, the grinding device 1 includes a position detecting unit 35 that detects the position of the grinding unit 20 in the Z-axis direction. The position detection unit 35 includes a linear scale provided along the elevating unit 30 in parallel with the Z-axis direction, and a reading head movably provided together with the grinding unit 20 in the Z-axis direction to read the scale of the linear scale. Has been done. The position detection unit 35 outputs the information indicating the scale of the linear scale read by the reading head to the origin position setting unit 50 as information indicating the position of the grinding unit 20 in the Z-axis direction.

As shown in FIG. 1, the balance cylinder 40 is provided on the side opposite to the elevating unit 30 (on the −Y direction side in FIG. 1) with respect to the center of gravity of the grinding unit 20, and the grinding unit 20 is attached to the grinding unit 20. By lifting with a force corresponding to the weight, the own weight of the grinding unit 20 is offset. Although two balance cylinders 40 are provided in the example of the present embodiment shown in FIG. 2, the present invention is not limited to this, and one balance cylinder 40 may be provided, or three or more balance cylinders 40 may be provided.

The balance cylinder 40 is an air cylinder in the present embodiment, and as shown in FIGS. 1 and 2, a cylindrical cylinder case 41 and a piston 42 disposed inside the cylinder case 41 and sliding inside the case. A piston rod 43, which is inserted into the cylinder case 41 and whose upper end is attached to the piston 42, is provided. The lower end of the piston rod 43 is connected to the grinding unit 20.

The cylinder case 41 is formed with a supply port 44 to which air such as compressed air is supplied from the air supply source 45 at a position below the sliding range of the piston 42. The air supply source 45 supplies air to the space below the piston 42 inside the cylinder case 41 through the supply port 44.

A balance cylinder adjusting portion 46 is provided in a communication passage that communicates between the supply port 44 of the cylinder case 41 and the air supply source 45. As shown in FIGS. 1, 2 and 3, the balance cylinder adjusting unit 46 includes a precision pressure regulator 47, an internal pressure detecting unit 48, and a control unit 49.

The precision pressure regulator 47 adjusts the pressure of the air supplied from the air supply source 45 to the inside of the cylinder case 41. The precision pressure regulator 47 is an electropneumatic regulator in this embodiment. The internal pressure detecting unit 48 detects the internal pressure of the cylinder case 41, that is, the internal pressure of the cylinder of the balance cylinder 40. The internal pressure detection unit 48 outputs the detected cylinder internal pressure to the origin position setting unit 50. The control unit 49 controls the precision pressure regulator 47 and the internal pressure detection unit 48. The balance cylinder adjusting unit 46 supplies air to the inside of the cylinder case 41 by the precision pressure regulator 47 so as to keep the cylinder internal pressure constant based on the cylinder internal pressure detected by the internal pressure detecting unit 48 by the control unit 49. By adjusting the pressure of, the balance cylinder 40 is adjusted so that the force for lifting the grinding unit 20 is kept constant.

The origin position setting unit 50 sets the origin position of the grinding wheel 26 with respect to the chuck table 10. As shown in FIG. 1, the origin position setting unit 50 is electrically connected to the position detection unit 35 and the internal pressure detection unit 48 so that information and communication can be performed.

The origin position setting unit 50 has a control unit 51. The control unit 51 acquires information on the position of the grinding unit 20 in the Z-axis direction by a signal from the position detecting unit 35. The control unit 51 acquires information on the cylinder internal pressure of the balance cylinder 40 from a signal from the internal pressure detecting unit 48. The control unit 51 sets the origin position of the grinding unit 20 in the Z-axis direction based on the acquired information on the position of the grinding unit 20 in the Z-axis direction and the information on the cylinder internal pressure of the balance cylinder 40.

The control unit 51 is generated when the grinding wheel 26 lowered to the chuck table 10 by the elevating unit 30 comes into contact with the holding surface 11 of the chuck table 10 or a contact surface having a predetermined height relationship with the holding surface 11. The change in the cylinder internal pressure of the balance cylinder 40 is detected by the internal pressure detecting unit 48. Here, in the present embodiment, the contact surface having a predetermined height relationship with the holding surface 11 is, for example, the back surface opposite to the front surface of the workpiece 100 that is suction-held on the holding surface 11 of the chuck table 10. Is. The control unit 51 sets the position in the Z-axis direction of the grinding unit 20 detected by the position detecting unit 35 at the time when the internal pressure detecting unit 48 detects the change in the cylinder internal pressure of the balance cylinder 40 as the origin position.

In the present embodiment, the control unit 49 and the origin position setting unit 50 both include a computer system. The control unit 49 and the origin position setting unit 50 each have an arithmetic processing device having a microprocessor such as a CPU (Central Processing Unit) and a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory). It has a storage device and an input / output interface device. The arithmetic processing unit of the control unit 49 outputs a control signal for controlling the precision pressure regulator 47 and the internal pressure detection unit 48 to the precision pressure regulator 47 and the internal pressure detection unit 48 via the input / output interface device. The arithmetic processing unit, storage device, and input / output interface device of the origin position setting unit 50 realize the function of the control unit 51 by executing arithmetic processing according to a computer program stored in the storage device. Although the control unit 49 and the origin position setting unit 50 are separately provided in the present embodiment, the present invention is not limited to this, and the origin position setting unit 50 may be integrated.

Further, as shown in FIG. 1, the grinding device 1 includes a grinding amount detecting unit 60. The grinding amount detection unit 60 is provided near the outer periphery of the holding surface 11 of the chuck table 10. In the present embodiment, the grinding amount detecting unit 60 is a contact type height detecting device, and includes contact type probes 61 and 62 for detecting the height of the contacted position.

When the workpiece 100 is held on the holding surface 11 of the chuck table 10, the probe 61 comes into contact with the holding surface 11 from above in a region outside the outer edge of the workpiece 100, so that the holding surface 11 Detect height. When the workpiece 100 is held on the holding surface 11 of the chuck table 10, the probe 62 comes into contact with the workpiece 100 from above in a region slightly inside the outer edge of the workpiece 100. The height of the upper surface of the work piece 100 is detected. The grinding amount detection unit 60 detects the thickness of the workpiece 100 in a region slightly inside the outer edge of the workpiece 100 based on the height information detected by the probes 61 and 62, respectively.

In the present embodiment, the grinding amount detection unit 60 includes contact-type probes 61 and 62, but the present invention is not limited to this, and for example, the inside and outside of the outer edge of the workpiece 100. Is irradiated with a laser beam having a wavelength reflected by the holding surface 11 and the workpiece 100, and receives an interference wave of the laser beam reflected from both of them, and the interference wave is received by the workpiece 100 based on the light reception. It may be in the form of detecting the thickness of the workpiece 100 in the region slightly inside the outer edge.

Further, the grinding device 1 includes a control device (not shown). This control device controls each component of the grinding device 1 to realize the grinding process by the grinding device 1. The control device grinds the workpiece 100 with the grinding wheel 22 according to, for example, the grinding conditions of the workpiece 100 input and set by the operator. This control device includes a computer similar to the origin position setting unit 50. The control device may be integrated with the origin position setting unit 50.

Next, this specification describes an example of the operation of the grinding apparatus 1 according to the embodiment based on the drawings. FIG. 4 is a flowchart showing an example of a processing procedure for the operation of the grinding device 1 of FIG. FIG. 5 is a graph showing an example of a change in the cylinder internal pressure of the balance cylinder 40 detected by the grinding device 1 of FIG. In the following, first, the operation of the grinding device 1 to set the origin position when the workpiece 100 is not suction-held on the holding surface 11 of the chuck table 10 will be described.

First, the grinding device 1 positions the chuck table 10 and the grinding unit 20 so that the holding surface 11 of the chuck table 10 and at least a part of the grinding wheel 26 of the grinding unit 20 oppose each other in the Z-axis direction. The grinding device 1 then lowers the grinding wheel 26 toward the chuck table 10 by the elevating unit 30 according to the operation of the operator (step 1001 in FIG. 4). The grinding device 1 is not limited to this in the present invention, and the grinding wheel 26 may be automatically lowered toward the chuck table 10 by the elevating unit 30 by a control device (not shown).

The balance cylinder adjusting unit 46 supplies the grinding unit 20 to the inside of the cylinder case 41 by the precision pressure regulator 47 by the control unit 49 while the grinding unit 20 is being lowered toward the chuck table 10 by the elevating unit 30 during the execution of step 1001. Adjust so that the pressure of the air to be used is constant. Therefore, as shown in FIG. 5, the internal pressure detecting unit 48 detects that the internal pressure of the balance cylinder 40 is constant and substantially unchanged during the execution of step 1001.

When the grinding wheel 1 continues to lower the grinding wheel 26 toward the chuck table 10 by the elevating unit 30, the grinding wheel 26 comes into contact with the holding surface 11 of the chuck table 10. As a result, the piston 42 of the balance cylinder 40 momentarily receives the reaction force that the grinding wheel 26 receives from the holding surface 11 of the chuck table 10 via the piston rod 43. Then, the balance cylinder adjusting unit 46 adjusts the pressure of the air supplied to the inside of the cylinder case 41 by the precision pressure regulator 47 with respect to the reaction force received by the piston 42, and as a result, the balance cylinder 40 As shown in FIG. 5, the cylinder internal pressure of the above increases momentarily.

Therefore, in the grinding device 1, after continuing to carry out the above-mentioned step 1001, the control unit 51 causes the internal pressure detecting unit 48 to come into contact with the grinding wheel 26 and the holding surface 11 of the chuck table 10. The change in the cylinder internal pressure of 40 is detected (step 1002 in FIG. 4).

When the grinding wheel 26 comes into contact with the holding surface 11 of the chuck table 10, the grinding device 1 raises the grinding unit 20 by the elevating unit 30 and retracts it from the chuck table 10 according to the operation of the operator. The grinding device 1 is not limited to this in the present invention, and the grinding unit 20 may be automatically raised by the elevating unit 30 and retracted from the chuck table 10 by a control device (not shown).

In the grinding device 1, the position detection unit 35 obtains information on the position of the grinding unit 20 in the Z-axis direction detected by the position detection unit 35 when the control unit 51 detects a change in the cylinder internal pressure of the balance cylinder 40 in step 1002. (Step 1003 in FIG. 4). The grinding device 1 is the position of the grinding unit 20 when the grinding wheel 26 and the holding surface 11 of the chuck table 10 come into contact with each other at the position in the Z-axis direction of the grinding unit 20 acquired by the control unit 51 in step 1003. As the origin position (step 1004 in FIG. 4). In the grinding device 1, the control unit 51 stores the position in the Z-axis direction of the grinding unit 20 acquired in step 1003 in the storage device of the origin position setting unit 50 as the origin position.

After performing step 1004, the grinding apparatus 1 carries the workpiece 100 onto the holding surface 11 of the chuck table 10 and sucks and holds the workpiece 100 on the holding surface 11 of the chuck table 10. The grinding device 1 then chucks the grinding unit 20 by the elevating unit 30 while rotating the grinding wheel 22 around the Z axis by the spindle 21 under preset conditions based on the origin position set in step 1004. By pressing the workpiece 100 held by the holding surface 11 of the table 10 along the Z-axis direction, a grinding process for grinding the workpiece 100 is performed (step 1005 in FIG. 4).

In the present embodiment, the grinding device 1 holds the chuck table 10 when maintenance on the chuck table 10 side such as replacement of the chuck table 10 is performed and when the grinding wheel 22 mounted on the grinding unit 20 is replaced. In order to register the positional relationship between the surface and the lower end of the grinding wheel 22, steps 1001 to 1004 are performed to set the origin position.

Further, the grinding device 1 holds the chuck table 10 instead of performing the operation of setting the origin position when the workpiece 100 is not suction-held on the holding surface 11 of the chuck table 10. This may be performed when the workpiece 100 is suction-held on the surface 11. In this case, the operation of setting the origin position of the grinding device 1 is changed at the point described below. The grinding apparatus 1 carries the workpiece 100 onto the holding surface 11 of the chuck table 10 instead of after the execution of step 1004, and sucks and holds the workpiece 100 on the holding surface 11 of the chuck table 10. do. Then, when the grinding device 1 performs step 1001 and continues to lower the grinding wheel 26 toward the chuck table 10 by the elevating unit 30, the grinding wheel 26 is held by the holding surface 11 of the chuck table 10. Contact the back of 100. Here, the back surface of the workpiece 100 held by the holding surface 11 of the chuck table 10 corresponds to a contact surface having a predetermined height relationship with the holding surface 11 in the present invention. Therefore, in step 1002, in step 1002, the control unit 51 balances the internal pressure detecting unit 48 due to the contact between the grinding wheel 26 and the back surface of the workpiece 100 on the holding surface 11 of the chuck table 10. The change in the cylinder internal pressure of the cylinder 40 is detected. Further, in step 1004, in step 1004, the control unit 51 positions the position of the grinding unit 20 acquired in step 1003 in the Z-axis direction of the work piece 100 on the holding surface 11 of the grinding wheel 26 and the chuck table 10. Assuming that it is the position of the grinding unit 20 when it comes into contact with the back surface, it is set as the origin position having a definition different from the operation of setting the origin position described above. Further, in the grinding device 1, in addition to the workpiece 100, a substrate for registering the origin position having a size and material similar to that of the workpiece 100 may be used on the holding surface 11 of the chuck table 10. In this case, it is preferable that the workpiece 100 and the chuck table 10 are not damaged by the contact of the grinding wheel 26.

In the grinding device 1 according to the embodiment having the above configuration, the control unit 51 lowers the grinding wheel 26 to the chuck table 10 by the elevating unit 30, and the grinding wheel 26 holds the holding surface 11 of the chuck table 10 or holds the grinding wheel 26. The grinding unit 20 detected by the position detecting unit 35 when the internal pressure detecting unit 48 detects a change in the cylinder internal pressure of the balance cylinder 40 that occurs when the contact surface has a predetermined height relationship with the surface 11. The position in the Z-axis direction is set as the origin position. Therefore, the grinding device 1 according to the embodiment moves the grinding unit up and down while lowering the grinding unit toward a gap gauge having a predetermined thickness placed on the holding surface as in the conventional case, and causes a gap between the grinding wheel and the grinding wheel. While checking the gap with the gauge, the operator does not need to be proficient and burdensome to register the origin position by referring to the position where the grinding wheel comes into contact with the feeler gauge. It can be limited to 20 ascending / descending. Therefore, the grinding device 1 according to the embodiment has an effect that the registration of the origin position can be performed more accurately and safely while reducing the burden on the operator.

The present invention is not limited to the above embodiment. That is, it can be modified in various ways without departing from the gist of the present invention.

1 Grinding device 10 Chuck table 11 Holding surface 20 Grinding unit 21 Spindle 22 Grinding wheel 25 Base 26 Grinding grindstone 30 Elevating unit 35 Position detection unit 40 Balance cylinder 48 Internal pressure detection unit 50 Origin position setting unit 51 Control unit 100 Work piece

Claims (1)

Grinding to grind the workpiece held on the chuck table with a chuck table that holds the workpiece on the holding surface and a grinding wheel that has a spindle with a rotation axis perpendicular to the holding surface and is attached to the lower end of the spindle. A unit, an elevating unit that raises and lowers the grinding unit in a direction perpendicular to the holding surface, a balance cylinder that lifts the grinding unit with a force corresponding to the weight of the grinding unit, and an origin position of the grinding grind with respect to the chuck table. It is a grinding device provided with an origin position setting unit for setting.
The origin position setting unit is
It has a position detecting unit that detects the position of the grinding unit that moves up and down by the elevating unit, and a control unit that sets the origin position based on a signal from the internal pressure detecting unit that detects the cylinder internal pressure of the balance cylinder. death,
The control unit is
The grinding wheel is lowered to the chuck table by the elevating unit, and the grinding wheel is generated when the grinding wheel comes into contact with the holding surface of the chuck table or a contact surface having a predetermined height relationship with the holding surface. A grinding device characterized in that the position of the grinding unit detected by the position detecting unit when a change in the cylinder internal pressure of the balance cylinder is detected is set as the origin position.

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