JP2585486Y2 - Polishing device for semiconductor wafer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a semiconductor wafer.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional polishing apparatus for a semiconductor wafer (hereinafter referred to as a wafer).
Reference numeral 1 denotes a grindstone shaft which is rotated by driving of a driving device (not shown). A connecting plate 32 is provided at one end of the grindstone shaft 31. A grindstone mounting plate 33 is attached to the lower surface of the connecting plate 32, and a plurality of grindstones 34 are arranged on the circumference of the grindstone mounting plate 33 as shown in FIG. And
Depending on the grain size of the grindstone 34, it can be divided into three stages of rough cutting, medium cutting and finish cutting. On the other hand, reference numeral 35 in the figure denotes a chuck table disposed on a circumferential portion of a main table (not shown), and a wafer 36 as a workpiece is suction-fixed to the upper surface of the chuck table 35.

In the conventional semiconductor wafer polishing apparatus, the surface of the wafer 36 is polished by the following operation. That is, when the grindstone shaft 31 is rotated at a high speed by the drive of the driving device, the grindstone mounting plate 3
3 and the grindstone 34 rotate. On the other hand, a predetermined amount of polishing cut is provided to the wafer 36, and the main table (not shown) is slowly rotated at a constant speed to horizontally move the wafer 36. Thereby, the surface of the wafer 36 is gradually polished by the grindstone 34, and the polished surface 37 shown in FIG. 1 is formed. Such a polishing operation is performed in the order of rough cutting, medium cutting, and finish cutting, whereby the polished surface 37 of the wafer 36 is finished.

[0004]

However, in the above-mentioned conventional polishing apparatus, fine irregularities remain on the polishing surface 37 of the wafer 36 due to abrasion or crushing of the grindstone 34, and the finished polishing surface 37 becomes a mirror surface. There were problems, such as getting cloudy without getting lost. Further, due to the fine irregularities remaining on the polishing surface 37, the grinding stone 34 for the wafer 36 is formed.
However, there is a problem that the polishing pressure is not uniform and the polished wafer 36 is warped.

The present invention has been made to solve the above problem, and has as its object to provide an apparatus for polishing a semiconductor wafer without leaving fine irregularities on the polishing surface of the wafer.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above object, and has a connecting plate provided at one end of a grinding wheel shaft, a grinding wheel mounting plate attached to the connecting plate, and A plurality of whetstones disposed on a circumferential portion of the whetstone mounting plate, and a pressing body having elasticity is stretched inside the plurality of whetstones disposed at the circumferential portion of the whetstone mounting plate. In addition, the present invention provides a polishing apparatus for a semiconductor wafer in which a polishing abrasive layer formed by bonding abrasive grains finer than a grindstone is applied to the surface of the pressing body.

[0007]

According to the semiconductor wafer polishing apparatus of the present invention,
The polishing abrasive layer is pressed against the wafer surface at a predetermined pressure by the elasticity of the pressing body stretched inside the grindstone, and the polishing abrasive layer is moved on the wafer surface while rotating in this state, so that the polishing abrasive layer is on the polishing surface. Fine asperities are removed by polishing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in the figure, in the wafer polishing apparatus of the present embodiment, a connecting plate 12 is provided at one end of a grinding wheel shaft 11, and a grinding wheel mounting plate 13 is attached to the connecting plate 12. Then, on the circumferential portion of the whetstone mounting plate 13,
A plurality of whetstones 14 are provided. In addition, in the polishing apparatus of the present example, an elastic pressing body 15 is stretched inside a plurality of grinding wheels 14 arranged on a circumferential portion of the grinding wheel mounting plate 13, and the pressing body 15 Abrasive grain layer 1 on the surface
6 are applied.

More specifically, the pressing body 15 is a thick string-like elastic body made of, for example, hard rubber.
As shown in the figure, the wheels are arranged radially from the center of the whetstone mounting plate 13. At this time, each end 15a of the pressing body 15 is fixed to the lower surface of the grindstone mounting plate 13 by a mounting screw or the like (not shown), whereby the pressing body 15 is stretched inside the grinding stone 14.

On the other hand, the abrasive grain layer 16 is made of, for example, an alumina abrasive or a diamond abrasive.
This is a layer of very fine abrasive grains in which abrasive grains finer than the grindstone 14 are bound by a binder. This abrasive grain layer 16 is adhered to the surface of the pressing body 15 with an adhesive or the like. The polishing abrasive layer 16 does not need to be applied to the entire surface of the pressing body 15. Therefore, in this embodiment, the polishing abrasive layer 16 is provided only on the surface facing the workpiece 17, that is, on the lower surface of the pressing body 15. 16 were deposited.

In the polishing apparatus of this embodiment having such a configuration, the surface of the wafer 17 is polished by the following operation. That is, when the grinding wheel shaft 11 is rotated at a high speed by driving of a driving device (not shown), the grinding wheel shaft 11 is rotated.
The grinding wheel mounting plate 13, the grinding wheel 14, and the pressing body 15
Rotates. On the other hand, the wafer 17 fixed by suction on the chuck table 18 is provided with a predetermined amount of polishing cut, and the main table (not shown) is slowly rotated at a constant speed to move the wafer 17 horizontally. As a result, the surface of the wafer 17 is gradually polished by the grindstone 14, and a polished surface 19 is formed after the grindstone 14 passes. At this time, fine irregularities may remain on the polished surface 19 of the wafer 17 due to wear or clogging of the grindstone 14.

However, in the polishing apparatus of this embodiment, the whetstone 1
The pressing body 15 stretched inward from the surface 4 presses the polishing abrasive grain layer 16 against the surface of the wafer 17 by its own elasticity. Then, the polishing abrasive grain layer 16 moves on the surface of the wafer 17 following the grindstone 14 while rotating with the grindstone shaft 11, and polishes and removes fine irregularities left on the polishing surface 19 one after another. As a result, the finished wafer 17
No fine irregularities remain on the polished surface 19 of the wafer 1.
The polished surface 19 of 7 has a mirror-like finish without clouding.

In the polishing apparatus of this embodiment, the grain size of the abrasive grain layer 16 and the pressing force of the abrasive grain layer 16 against the surface of the wafer 17 depend on the grain size of the grindstone 14 and the rotation speed of the main table (wafer 17). Is set as appropriate depending on, for example, the speed of movement of This is because the size of the unevenness left on the polished surface 19 of the wafer 17 depends on the grain size of the grindstone 14 and the size of the wafer 1.
This is because it is greatly affected by the moving speed and the like. Note that the pressing force of the abrasive grain layer 16 against the surface of the wafer 17 can be freely set according to the material and shape of the pressing body 15.

In the above embodiment, the pressing member 15
Although the polishing abrasive layer 16 is pressed against the surface of the wafer 17 by giving elasticity to itself, the present invention is not limited to this, and for example, a plate is provided between a grindstone mounting plate and a pressing body (having no elasticity). A spring member such as a spring or a compression coil spring may be interposed, and the polishing abrasive grain layer may be pressed against the wafer surface by utilizing the elasticity of the spring member.

[0015]

[Effects of the Invention] As described above, according to the present invention,
The polishing abrasive layer is pressed against the wafer surface at a predetermined pressure by the elasticity of the pressing body stretched inside the grindstone, and the polishing abrasive layer is moved on the wafer surface while rotating in this state, so that the polishing abrasive layer is on the polishing surface. Fine asperities are removed by polishing. As a result, no fine irregularities remain on the polished surface of the finished wafer, so that the polished surface of the wafer has a mirror-like finish without clouding. In addition, since there is no unevenness on the polished surface of the wafer, the polishing pressure of the grindstone on the wafer becomes uniform, thereby preventing the wafer from being warped during the polishing operation.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a bottom view of the whetstone mounting plate of the embodiment.

FIG. 3 is a side sectional view showing a conventional example.

FIG. 4 is a bottom view of a conventional whetstone mounting plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Grinding wheel shaft 12 Connecting plate 13 Grinding stone mounting plate 14 Grinding stone 15 Pressing body 16 Polishing abrasive grain layer

Continuation of the front page (56) References JP-A-62-162468 (JP, A) JP-A-61-226272 (JP, A) JP-A-61-144963 (JP, U) JP-A-61-144962 (JP) , U) Fully open 1986-644961 (JP, U) Fully open 1986-144960 (JP, U) Fully open 1986-144959 (JP, U) (58) Fields studied (Int. Cl. ⁶ , DB Name) H01L 21/304 B24B 7/22

Claims (1)

(57) [Scope of request for utility model registration] 1. A semiconductor wafer comprising: a connecting plate provided at one end of a grinding wheel shaft; a grinding wheel mounting plate mounted on the connecting plate; and a plurality of grinding wheels provided on a circumferential portion of the grinding wheel mounting plate. In the polishing apparatus, an elastic pressing body is stretched inside the plurality of grinding stones disposed on a circumferential portion of the grinding wheel mounting plate, and the surface of the pressing body has a particle size larger than that of the grinding stone. A polishing apparatus for a semiconductor wafer, comprising a polishing abrasive layer formed by bonding fine abrasive grains.