JP2002192460A - Grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device that can grind a workpiece to a uniform thickness. SOLUTION: The grinding device comprises a rotatably constructed chuck table 33 having a suction holding surface 351 on which the sheetlike workpiece W is placed, a spindle unit having a rotary shaft arranged parallel to the suction holding surface 351 of the chuck table 33, and a disklike grinding wheel 54 mounted on the rotary shaft 53 of the spindle unit. The suction holding surface 351 of the chuck table is formed into a cone with the vertex on the rotational axis, and the grinding wheel is relatively moved parallel to the suction holding surface in a grinding region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus for grinding a thin workpiece such as a semiconductor wafer.

[0002]

2. Description of the Related Art As is well known to those skilled in the art, in a semiconductor device manufacturing process, the surface of a semiconductor wafer is ground to form a substantially disk-shaped semiconductor wafer to a predetermined thickness. Such a surface grinding apparatus for grinding the surface of a semiconductor wafer includes a rotatable chuck table having a suction holding surface on which a workpiece is placed, and a rotating table arranged in the rotation axis direction of the chuck table. A spindle unit having a spindle, and a cup-shaped grindstone attached to the lower end of the rotating shaft of the spindle unit. The end surface of which is held by suction on the suction holding surface of the chuck table while rotating the grindstone. 2. Description of the Related Art Grinding apparatuses that are brought into contact with a workpiece and provided with a predetermined depth of cut for grinding are generally used.

However, when a thin plate-like workpiece such as a semiconductor wafer is ground by the above-described grinding apparatus, the following problems occur. (1) Since the spindle unit is disposed perpendicular to the chuck table, when thermal expansion occurs in the spindle unit, it directly affects the cutting depth of the cup-shaped grindstone, and the work piece has a desired thickness. Difficult to grind. (2) Since the contact area between the cup-shaped grindstone and the workpiece is large, the grinding load is large, so that high rigidity is required and the entire apparatus becomes large. (3) Since the spindle unit arranged perpendicular to the surface of the work is cut and fed in the axial direction (perpendicular to the surface of the work), the cutting control is directly affected by the distortion of the spindle. Therefore, the cutting feed must be controlled while the thickness of the workpiece is actually measured by a contact-type sensor, and as a result, the surface of the workpiece is damaged. (4) Since the cutting load is large, each member constituting the chuck table, the spindle unit, and the like is distorted. In order to reduce the influence of this distortion and increase the grinding accuracy of the workpiece, the cutting feed is stopped. So-called spar-out and relief grinding must be performed, resulting in poor productivity. (5) In order to reduce the influence of the distortion of each member constituting the chuck table, the spindle unit and the like, the rigidity of each member is required, and the grinding device becomes large.

In order to solve the above-mentioned problem, a rotatable chuck table having a suction holding surface on which a thin plate-shaped workpiece is placed, and a chuck table arranged in parallel with the suction holding surface of the chuck table are provided. A spindle unit provided with a rotating shaft, and a disk-shaped grindstone (straight grindstone) mounted on the rotating shaft of the spindle unit. The grindstone is rotated and its outer peripheral surface is attracted to a suction holding surface of a chuck table. Japanese Patent Application Laid-Open No. 61-16477 discloses a grinding device configured to relatively move a grindstone and a workpiece in a grinding feed direction while making contact with the held workpiece in a grinding area.
No. 3 discloses this.

However, in the grinding apparatus disclosed in the above publication, the thin plate-shaped workpiece is supported along the suction holding surface of the chuck table. If the surface is not formed in a plane perpendicular to the rotation axis, it cannot be ground to a uniform thickness. However, it is difficult to form the suction holding surface of the chuck table in a perfect plane, and the central portion is depressed from the outer peripheral portion or the central portion protrudes from the outer peripheral portion. In the case where the workpiece is suction-held on the suction-holding surface whose central portion is depressed from the outer peripheral portion and ground, if the cutting depth is determined at the outer peripheral portion and the grinding is performed, the central portion is not ground.
On the other hand, if the workpiece is sucked and held on the suction holding surface whose central part protrudes from the outer peripheral part and is ground, if the cutting depth is determined at the outer peripheral part and the grinding is performed, the central part is excessively ground more than necessary. There is a problem that it becomes thin.

[0005] The present invention has been made in view of the above-mentioned facts, and a main technical problem thereof is to provide a grinding apparatus capable of grinding a workpiece to a uniform thickness.

[0006]

According to the present invention, there is provided, in accordance with the present invention, a rotatable chuck table having a suction holding surface on which a thin plate-like workpiece is placed. A spindle unit having a rotating shaft disposed in parallel with the suction holding surface of the chuck table, and a disk-shaped grindstone mounted on the rotating shaft of the spindle unit, and rotating the grindstone to rotate the outer peripheral surface thereof. In a grinding apparatus configured to relatively move the grindstone and the chuck table in a grinding feed direction while being in contact with a workpiece suction-held on the suction holding surface of the chuck table, the suction holding surface of the chuck table is provided. Characterized in that the grinding wheel is formed in a conical shape having an apex on the rotation axis and the grindstone is relatively moved in parallel with the suction holding surface in a grinding area. There is provided.

It is desirable that the slope of the suction holding surface formed in the conical shape is set to 0.001 to 0.00001.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a grinding machine constituted according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a main part of a grinding apparatus constructed according to the present invention. The grinding device in the illustrated embodiment includes a stationary base 2, a chuck table mechanism 3 movably disposed in a direction indicated by an arrow X on the stationary base 2 to hold a workpiece, and a stationary base 2. A spindle support mechanism 4 movably disposed in a direction indicated by an arrow Y which is a grinding feed direction, and a spindle unit 5 movably disposed in a direction indicated by an arrow Z which is a cutting direction in the spindle support mechanism 4 Is provided.

The chuck table mechanism 3 includes two guide rails 31 and 32 disposed in parallel on the stationary base 2 along a direction indicated by an arrow X, and an arrow X on the guide rails 31 and 32. The chuck table 33 is provided so as to be movable in the direction shown by the arrow. This chuck table 33
Has a suction chuck support 34 movably disposed on the guide rails 31 and 32, and a suction chuck 35 mounted on the suction chuck support 34. The surface of the suction chuck 35 For example, a disc-shaped semiconductor wafer W, which is a workpiece, is held on a certain suction holding surface 351 by suction means (not shown). The chuck table 3 is driven to rotate in a direction indicated by an arrow by a rotation drive mechanism (not shown). In the illustrated embodiment, the suction chuck 35 is made of a porous ceramic material, and its suction holding surface 351 is formed in a conical shape with the vertex on the rotation axis OA as shown in FIG. . The slope (H / R) of the suction holding surface 351 formed in this conical shape is 0.00001-
It is set to 0.001.

Further, the chuck table mechanism 3 includes a driving means 36 for moving the chuck table 33 along the two guide rails 31 and 32 in the direction indicated by the arrow X. The driving means 36 is provided with the two guide rails 3.
Male thread rod 361 disposed in parallel between 1 and 32
And a drive source such as a pulse motor 362 for rotationally driving the male screw rod 361. Male thread rod 3
41 is rotatably supported at one end by a bearing block (not shown) fixed to the stationary base 2, and the other end thereof is operatively connected to the output shaft of the pulse motor 362 via a speed reducer (not shown). I have. The male screw rod 361 is screwed into a female screw hole (not shown) formed in a female screw block (not shown) protruding from the lower surface of the central part of the suction chuck support 34 constituting the chuck table 33. Accordingly, by driving the male screw rod 361 to rotate forward and reverse by the pulse motor 362, the chuck table 33 moves along the guide rails 31, 32 in the direction indicated by the arrow X in FIG. And the processing position shown in the actual battle.

The spindle support mechanism 4 includes a stationary base 2
Two guide rails 41 and 42 arranged in parallel on the top,
A movable support base 43 is provided on the guide rails 41 and 42 so as to be movable in a direction indicated by an arrow Y. The movable support base 43 includes a movable support portion 431 movably disposed on the guide rails 41 and 42, and the movable support portion 43.
1 and a spindle mounting section 432 attached to the spindle motor 1. The spindle mounting portion 432 is provided with two guide rails 432a and 432a extending in the direction indicated by the arrow Z in parallel. The spindle support mechanism 4 includes a driving unit 44 for moving the movable support base 43 along the two guide rails 41 and 42 in the direction indicated by the arrow Y. The driving means 44 is provided with the two guide rails 4.
Male thread rod 441 disposed in parallel between 1, 42
And a drive source such as a pulse motor 442 for rotationally driving the male screw rod 441. Male thread rod 4
One end of 41 is rotatably supported by a bearing block 443 fixed to the stationary base 2, and the other end is operatively connected to the output shaft of the pulse motor 442 via a speed reducer (not shown). . The male screw rod 44
1 is screwed into a through female screw hole formed in a female screw block (not shown) protrudingly provided on the lower surface of the central portion of the movable support portion 431 constituting the movable support base 43. Accordingly, by driving the male screw rod 441 to rotate forward and reverse by the pulse motor 442, the movable support base 43 is rotated.
Is moved along the guide rails 41 and 42 in the direction indicated by the arrow Y.

The spindle unit 5 includes a spindle holder 51 and a spindle housing 52 attached to the spindle holder 51. The spindle holder 51 has two guide rails 432 provided on the spindle mounting portion 432 of the spindle support mechanism 4.
a and 432a, two guided rails 51a, 51a slidably fitted to each other are provided.
By fitting the guide rails 1a and 51a to the guide rails 432a and 432a, the spindle holder 51 is supported so as to be movable in the direction indicated by the arrow Z. As shown in FIG. 2, a rotary shaft 53 is rotatably supported on the spindle housing 52 in parallel with the suction holding surface 351 in the grinding area G of the suction chuck 35. The rotary shaft 53 is disposed inside the spindle housing 52. It is designed to be driven to rotate by a provided rotation drive mechanism (not shown). A disk-shaped grindstone 54 is attached to the tip of the rotating shaft 53. The grindstone 54 grinds the workpiece by rotating and contacting the outer peripheral surface with the workpiece held on the suction holding surface 351 of the suction chuck 35 constituting the chuck table 33.

The spindle unit 5 includes a driving unit 5 for moving the spindle holder 51 in the direction indicated by the arrow Z along the two guide rails 432a and 432a.
5 is provided. The driving means 55 is provided with the driving means 36.
And 44, a male screw rod (not shown) disposed between the guide rails 432a and 432a, and a drive source such as a pulse motor 552 for rotationally driving the male screw rod. By driving the male screw rod (not shown) in forward and reverse directions,
Connect the spindle unit 5 to the guide rails 432a, 432a.
Along the direction indicated by arrow Z.

Here, the conical suction holding surface 351 of the suction chuck 35 constituting the chuck table 33 and the movement of the grindstone 54 in the direction of the arrow Y which is the grinding feed direction will be described. As shown in FIG. 2, for example, when a thin plate-shaped workpiece W is suction-held on a suction holding surface 351 formed in a conical shape with a radius of 100 mm and a rotation axis OA section raised by about 10 μm, the workpiece W is sucked. Holding surface 3
Since the slope of the cone of 51 is very small, the suction holding surface 35
1. Therefore, the workpiece W sucked and held on the suction holding surface 351 has a conical shape like the suction holding surface 351. In the embodiment shown in FIG. 2, the chuck table 33 connects the rotation axis OA to the suction holding surface 3.
The rotating shaft 53 provided with the grindstone 54 is horizontally disposed, and the grindstone 54 is parallel to the suction holding surface 351 in the grinding area G in the arrow Y direction. It is configured to be moved.
That is, the grindstone 5 is configured to relatively move in parallel with the suction holding surface 351 in the grinding area G. Accordingly, the chuck table 33 is rotated, and while the grindstone 54 is being rotated, a predetermined cutting amount is given to the grindstone 54 on the outer peripheral portion of the workpiece W, and the grindstone 54 moves in the direction of the arrow Y toward the rotation axis OA of the suction holding surface 351. By doing so, the entire surface of the workpiece W can be ground when the grindstone 54 reaches the rotation axis OA. When the grinding stone 54 passes through the rotation axis OA, it is separated from the surface of the workpiece W, so that the grinding action does not occur. As described above, the grinding device in the illustrated embodiment uses the suction chuck 35 that forms the chuck table 33.
The suction holding surface 351 is formed in a conical shape, and the grindstone 54 is relatively moved in parallel with the suction holding surface 351 in the grinding area G. Therefore, the workpiece W sucked and held on the suction holding surface 351 is removed. It can be ground to a uniform thickness.

As described above, the present invention has been described based on the illustrated embodiments. However, the present invention is not limited to only the embodiments, and various modifications can be made within the technical idea of the present invention. For example, in the illustrated embodiment, an example is shown in which the rotation axis OA of the chuck table 33 is arranged at an angle corresponding to the inclination of the suction holding surface 351.
4 is attached to the suction holding surface 35 with respect to the horizontal.
It may be inclined by an angle corresponding to one gradient. In the illustrated embodiment, the grinding wheel 54 is moved in the arrow Y direction to execute the grinding feed. However, the chuck table 33 may be moved in the arrow Y direction.

[0017]

Since the grinding apparatus according to the present invention is constructed as described above, the following effects are obtained.

That is, according to the present invention, the chucking and holding surface of the chuck table is formed in a conical shape having the vertex on the rotation axis, and the grindstone is relatively moved in parallel with the suction and holding surface in the grinding area. Therefore, the workpiece sucked and held on the suction holding surface can be ground to a uniform thickness.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a grinding device configured according to the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a suction holding surface of a chuck table and a grinding feed direction of a grindstone in the grinding device of FIG. 1;

[Explanation of symbols]

 2: Stationary base 3: Chuck table mechanism 31, 32: Guide rail of chuck table mechanism 33: Chuck table 34: Suction chuck support base of chuck table 35: Suction chuck of chuck table 351: Suction holding surface of chuck table 36: Drive means for chuck table mechanism 4: Spindle support mechanism 41, 42: Guide rail of spindle support mechanism 43: Movable support base of spindle support mechanism 431: Moving support section of movable support base 432: Spindle mounting of movable support base Part 44: Driving means of spindle support mechanism 5: Spindle unit 51: Spindle holder of spindle unit 52: Spindle housing of spindle unit 53: Rotation axis of spindle unit 54: Grinding wheel 55: Driving means of spindle unit

Claims (2)

[Claims] A chuck table configured to be rotatable and provided with a suction holding surface on which a thin plate-shaped workpiece is placed; and a rotary shaft disposed in parallel with the suction holding surface of the chuck table. A spindle unit and a disk-shaped grindstone mounted on the rotating shaft of the spindle unit. The grindstone is rotated, and its outer peripheral surface is brought into contact with the workpiece held by suction on the suction holding surface of the chuck table. A grinding apparatus configured to relatively move the grindstone and the chuck table in a grinding feed direction, wherein the suction holding surface of the chuck table is formed in a conical shape having a vertex on a rotation axis, and the grindstone is formed. Characterized in that it is configured to relatively move in parallel with the suction holding surface in the grinding area. 2. The grinding apparatus according to claim 1, wherein the suction holding surface formed in a conical shape has a gradient set to 0.00001 to 0.001.