JPH01183372A - Grindstone - Google Patents

Abstract

PURPOSE:To perform the processes from rough grinding to finish grinding by one path by setting heights of projected grindstone fragments in annular shapes laminated at least doubly on the holding part of a rotating shaft to become higher from the outside to the inside. CONSTITUTION:There is provided a coaxial three layer structure of grindstone fragments 2, wherein the outermost layer, medium layer and innermost layer are formed with a rough grindstone fragment 5, finish grindstone fragment 6 and finish grindstone fragment 7, respectively. Such the grindstone fragments 2 are mounted on the holding part 1 (basic metal part) of a rotational shaft. The heights of the three grindstone fragments 5-7 are set to become higher from the outside to the inside while the grain sizes of the abrasive grains are set to become thinner from the outside to the inside. In grinding a semi-conductor wafer using such the cup type grindstone, the wafer is abutted sequentially on the rough grindstone fragment 5, medium grindstone fragment 6 and finish grindstone fragment 7 under rotation of the grindstone, thus it is possible to sequentially perform the processes from rough grinding to finish grinding by one path.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a grindstone suitable for, for example, surface grinding of semiconductor wafers.

(Prior Art) A vertical rotary table surface grinder is sometimes used for flattening the main surface of a semiconductor wafer. In this case, the wafer, which is the workpiece, is held on a circular table and rotates together with the circular table. At this time, when the end face of the grindstone is brought into contact with the wafer, the wafer is ground. By the way, in order to perform such surface grinding efficiently, one surface grinding machine is equipped with three rotating shafts, and each rotating shaft is equipped with a rough whetstone, a semi-finishing whetstone, and a finishing whetstone, and the rotary table is rotated. The wafer is finished to a predetermined thickness by passing through each grindstone in turn and by one-pass grinding.

However, although such surface grinding, which allows one-pass grinding, is efficient, it has the drawback that it requires a plurality of grindstone axes, resulting in an increase in the size of the device.

J (External problem A to be solved by the invention) The present invention has been made in consideration of the above circumstances, and is capable of performing rough machining, semi-finishing machining, and finishing machining in one pass with an l-axis surface grinder. The purpose is to provide whetstones.

A cup-shaped whetstone for surface grinding has a disc-shaped holding part and a grinding wheel piece part coaxially and at least doubly set up on this holding part, so that one-shot grinding is possible. This is what I did.

(Example) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 and 2 show the grindstone of this embodiment.

This whetstone consists of a ring-shaped base metal (1) and a ring-shaped base metal (1).
) and a grindstone piece (2) using, for example, A abrasive grains, C abrasive grains, or diamond abrasive grains, which are fitted and fixed in an evenly spaced manner on one end surface side of the grinding wheel (2). The base metal (1) is provided with a truncated conical recess (3) coaxially with the main body of the base metal (1) on one end side, and this recess (3).
A through hole (4) communicating with the base metal (1) is provided coaxially with the base metal (1). On the other hand, the whetstone piece (2) has a concentric three-layer structure, with the rough whetstone piece (5) forming the outermost layer, the intermediate finishing whetstone piece (62) forming the middle layer, and the innermost layer forming the rough whetstone piece (62). The finishing whetstone piece (consists of force).The rough whetstone piece (5)
consists of segment-shaped rough grindstone pieces (8) that are set up on the base metal +1) at equal intervals and perform rough grinding. Also,
The semi-finishing whetstone pieces 167 are segment-shaped semi-finishing whetstone pieces (9) that are set on the base metal (1) at equal intervals and perform semi-finishing grinding.
It consists of... Furthermore, the finishing whetstone pieces (7) are made up of segment-shaped finishing whetstone pieces that are planted on the base metal (1) at equal intervals and perform finish grinding. These grindstone pieces (8)..., (9]..., (II...) are arranged radially in a row in the radial direction. The grain size of the abrasive grains is provided so that it becomes finer as the area increases.
As shown in the figure, the height hl of the rough whetstone piece (8)...
・Δh1 higher than the height h2 of the semi-finishing whetstone piece (9)...
(for example, 165 μm) and a medium finishing whetstone (9
)... is set lower than the height h3 of the finishing grindstone pieces flQ... by Δh2 (for example, 5 μm). To set the grindstone piece height in this manner, a dedicated truing grindstone αυ as shown in FIG. 3 is used. This truing whetstone αυ has a stepped shape, and the top level has a rough finishing whetstone plate a, the middle level has a medium finishing whetstone plate (13), and the bottom level has a grinding stone plate (13) for finishing. The grindstone plate I is glued.The level difference between the rough finishing whetstone plate α3 and the semi-finishing whetstone plate a3 is Δh1, and the level difference between the rough finishing whetstone plate α3 and the semi-finishing whetstone plate Q
The height difference between the finishing grindstone plate I and the finishing grindstone plate I is set to Δh2, and these height differences are transferred to the grindstone piece part (2).

Next, the operation of the grindstone having the above structure will be described with reference to FIG.

First, a grindstone is attached to the main shaft of a vertical rotary table surface grinder. Next, the wafer a5 is placed and fixed on a circular table (not shown). Next, the height of the rotary table is adjusted so that the amount of cut into the wafer a9 by the rough grindstone pieces (8) becomes Δd. Then, when the main shaft and the rotary table are driven to rotate, the wafer aω is moved to the wafer (
c) This involves rough grinding and semi-finishing grinding.

Finish grinding is performed sequentially. That is, in FIG. 4, the area ■ is for the rough whetstone piece (8)..., the area Cυ is for the semi-finishing whetstone piece (9)...K, and the area @ is for the finishing whetstone piece 0. Groan... it's being ground down.

In this way, according to the grindstone of this embodiment, surface grinding from rough grinding to finish grinding can be performed in one pass using - number of grindstones. Therefore, the surface grinder does not require a main spindle for each grinding mode and only needs one main spindle, which has the advantage of making the device smaller and cheaper.

In addition, in the above embodiment, the grindstone piece part (2) is rough,
There are three layers, semi-finishing and finishing, but for example, the rough whetstone piece (5
) may be two or more layers, and a total of four or more concentric layers.

Furthermore, the rough whetstone piece (5) may be omitted, and only the semi-finishing whetstone piece (6) and the finishing whetstone piece (7) may be used. Furthermore, the grindstone piece portion (2) may be a continuous ring-shaped grindstone in the circumferential direction without being divided in the circumferential direction.

〔Effect of the invention〕

The grindstone of the present invention can perform surface grinding from rough grinding to finish grinding in one step. Therefore, a surface grinder using this grindstone can perform one-pass surface grinding even with a single main spindle, resulting in a smaller device and lower equipment costs.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view of a grindstone according to an embodiment of the present invention, Fig. 2 is a bottom view of the same, Fig. 3 is a diagram showing a truing grindstone dedicated to the grindstone according to an embodiment of the present invention, and Fig. 4 is the same. It is an explanatory diagram of a grinding action. (1): Bullion (holding part). (2): Grinding wheel piece. (8): Rough whetstone piece. (9): Semi-finishing whetstone piece. Material: Finished whetstone piece. Agent Patent Attorney Noriyuki Chika Yudo Mitsuyuki Matsuyama *2

Claims (4)

[Claims] (1) A cup-shaped grindstone for surface grinding, comprising a holding part attached to a rotating shaft, and an annular grindstone piece part coaxially and at least doubly planted on the holding part, and the grindstone piece The grindstone is characterized in that the protruding height from the holding part increases from the outside to the inside. (2) The whetstone according to claim 1, wherein the grain size of the abrasive grains in the whetstone piece portion becomes finer from the outside to the inside. (3) The grindstone according to claim 1, wherein the height difference in the grindstone piece portion decreases from the outside to the inside. (4) The grindstone according to claim 1, wherein the grindstone piece is composed of a plurality of segments divided in the circumferential direction.