JPS6322259A - Semiconductor wafer grinding method and device thereof - Google Patents

Abstract

PURPOSE:To prevent chipping and stone loading from occurring as well as to make accuracy of finishing in a wafer and service life in a grindstone improvable, by moving the wafer onto a machining surface of the finishing grindstone installed as connected to the same driving shaft after grinding it with a roughing grindstone, and chamfering it. CONSTITUTION:When a wafer 1 is set to a chucking part 3 completely, a driving shaft 4 is moved in a horizontal direction, and a roller 5 comes into contact with a copying model 2 whereby a rough grindstone 7 and the chucking part 3 are rotated, and rough grinding for the circumference of the wafer 1 takes place is accordance with a profile of the copying model 2. And, the driving shaft 4 is moved horizontally, and the roller 5 comes off the copying model 2. Next, when travel of the driving shaft 4 is over, the wafer 1 goes down up to a grinding position of a finishing grindstone 8, whereby the driving shaft 4 travels again and the copying model 2 an the roller 5 are made contact with each other, so that the wafer 1 is chamfered by the finishing grindstone 8. Thus, the wafer is ground by two grindstones different in grain size for both roughing and finishing operations so that accuracy of finishing and machining efficiency are well improved and, what is more, service life in these grindstones is prolongable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor wafer processing method and processing apparatus.

[Prior Art] A method using a tracing model is generally used to chamfer the outer periphery of a semiconductor wafer (hereinafter referred to as wafer).

In this method, a wafer grinding wheel is operated to follow the shape of the copy model, and the wafer is ground and chamfered into the same shape as the copy model.

FIG. 3 shows a conventional chamfering device. 1 is wafer, 2
3 is the copying model, 3 is the chucking for attaching wafer 1,
4 is a drive shaft, 5 is a roller, and 6 is a grindstone.

When the wafer 1 is attached to the chucking section 3, the drive shaft 4 moves in the horizontal direction, and the roller 5 attached to the drive shaft 4 comes into contact with the copying model 2. When the roller 5 comes into contact with the copying model 2, the grindstone 6 attached to the drive shaft 4 rotates according to the shape of the copying model.

At this time, the chucking section 3 also rotates, and the outer periphery of the wafer 1 is ground, thereby chamfering the wafer 1.

FIG. 4 shows the shape of a wafer processed by the chamfering apparatus shown in FIG. 3, with FIG. 4(a) being a plan view and FIG. 4(b) being a longitudinal sectional view. 1 indicates a wafer before processing, and 1' indicates a wafer after processing.

[Problems to be Solved by the Invention] As described above, in the conventional wafer chamfering process, the outer peripheral portion of the wafer is ground using a grindstone, but in this case, the following problems occur.

One of these is wafer chipping and grindstone clogging.

A fine-grained whetstone can be used to alleviate chipping, but this will cause clogging and shorten the life of the whetstone.

Also, if a coarse grindstone is used, clogging will be reduced but chipping will be increased.

As described above, the grindstone for grinding the wafer must be selected by taking both chipping and clogging into consideration.

Conventionally, a grindstone with a grain size of #500 to #1000 has been used, but it has not been possible to satisfy both requirements at the same time.

The next problem is the difference in the outer diameter of the wafer before and after processing, that is, the relationship between the grinding allowance and chipping and clogging.

The grinding allowance has traditionally been set at approximately 1.5 cm, but if stable grinding is possible even with this value increased, it is possible to use a different grinding process, which occurs when manufacturing compound semiconductor wafers using the boat method, for example. It is economical because it eliminates inconvenience and allows circular wafers to be obtained directly from wafers of arbitrary shapes, but the grinding allowance cannot be made too large because normally the larger the grinding allowance, the more likely chipping and clogging will occur. On the other hand, if the grinding allowance is set small in consideration of chipping and the life of the grinding wheel, it will be necessary to use wafers with small variations in outer diameter before processing, and the positioning accuracy when mounting the wafers will also become strict, making it difficult to achieve a yield rate of just eight. It will cause deterioration.

An object of the present invention is to provide a semiconductor wafer processing method and processing apparatus that improve wafer processing accuracy and grindstone life.

[Means for Solving the Problems] The present invention provides a semiconductor wafer processing method in which a grindstone attached to a mounting portion for grinding a wafer is driven in accordance with a copying model that defines a processing shape of the wafer to grind the wafer.
Using a rough grinding wheel for rough processing and a finishing wheel for chamfering, the wafer is ground by the rough grinding wheel, the wafer is moved to the processing surface of the finishing wheel, and the wafer is polished by the finishing wheel. The first feature is that the method has a wafer processing method for chamfering, and further, a copy model and a chucking part for attaching the wafer are attached to a copy model drive shaft, a roller and the wafer grinding wheel are attached to the grindstone drive shaft, In a semiconductor wafer processing apparatus that moves the roller to contact the copying model and drives the grindstone to grind the wafer into the same shape as the copying model, the grinding wheel drive shaft is provided with a rough grinding wheel for rough processing and chamfering. The second feature is that the finishing grindstone for processing is provided in a connected manner, and the purpose is achieved by improving the wafer processing accuracy and the life of the grinding wheel.

[Function] In the semiconductor wafer processing method of the present invention, a wafer is processed by driving a grindstone according to a copying model, but in this case, two grindstones, a rough grinding wheel and a finishing grinder, are used, and the wafer is ground by the rough grinding wheel. After that, the wafer is moved and chamfered using a finishing whetstone, so no excessive force is applied to the wafer during processing, and chipping and clogging of the grindstone can be prevented.

In addition, in the semiconductor wafer processing apparatus of the present invention, when driving the grindstone according to the copying model to grind the wafer, a rough grinding wheel for rough processing and a finishing grindstone for chamfering are connected to the same drive shaft, and the wafer is The wafer can be processed with high precision because the device is designed to move the grindstone to the processing surface of one grindstone and perform rough processing and chamfering in succession.

[Example code] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view of a main part showing an embodiment of a semiconductor wafer processing apparatus of the present invention. The same parts as in FIG. 3 are given the same reference numerals.

In the figure, 1 is a wafer, 2 is a copying model, and 3 is a chucking section. Reference numeral 7 denotes a rough grinding wheel, and 8 denotes a finishing grindstone, both of which are attached to the drive shaft 4. The use of two grindstones in this way is different from conventional processing equipment.

5 is a roller that comes into contact with the copying model 2.

The wafer chamfering method will be explained with reference to figures.

When the attachment of the wafer 1 to the chucking section 3 is completed, the drive shaft 4 moves in the horizontal direction, and the roller 5 comes into contact with the copying model 2. When the roller 5 and the copying model 2 come into contact, the rough grinding wheel 7 and the chucking part 3 rotate, and the outer circumference of the wafer 1 is roughly ground according to the shape of the copying model 2.

When rough grinding is completed, the drive shaft 4 moves horizontally, and the roller 5
follows model 2.

When the movement of the drive shaft 4 is completed, the wafer 1 is moved to the finishing grindstone 8.
The machine descends to the grinding position.

When the lowering of the wafer 1 is completed, the drive shaft 4 moves again, the copying model 2 and the roller 5 come into contact, and the wafer 1 is chamfered by the finishing grindstone 8.

In the processing device of this embodiment, the rough grinding wheel 7 has a grain size of #1.
A particle size of approximately #40 to #500 is used, and the particle size is determined by the material of the wafer 1 and the amount of grinding.

FIG. 2 shows a compound semiconductor wafer 1 manufactured by the boat method, with FIG. 2(a) being a plan view and FIG. 2(b) being a longitudinal sectional view. In the figure, when wafer 1 is processed into a circular wafer 1'', a grain size of about #320 is used, the grinding time is about 15 seconds, and the outer diameter of the circular wafer 1'' is approximately 0.0 mm smaller than the outer diameter of the finished wafer 1. Roughly ground to increase the size by .2 to 0.5 ml. After this rough edge grinding, finish grinding is performed, but the grain size of the finishing grindstone 8 at this time varies depending on the wafer material, grinding surface roughness, etc., as in the case of the rough grinding wheel 7. For example, in the case of compound semiconductor wafers, # Good results have been obtained using 800.

In addition, in Figure 1, when transitioning from rough grinding to finish grinding,
The structure is such that the whetstone is fixed and the wafer 1 is moved up and down, but in contrast, the wafer 1 is fixed and the whetstone 7 is moved up and down.
It is also possible to have a structure in which 8 and 8 are moved up and down.

As described above, by using this example, the following results can be obtained.

(1) By using two grindstones with different grain sizes for rough machining and finishing in chamfering of semiconductor wafers, machining accuracy and efficiency can be improved, and the life of expensive whetstones can be significantly extended.

(2) Since chipping defects of wafers can be significantly reduced, the yield of wafers can be improved and the cost can be reduced.

(3) In the case of boat method compound semiconductor wafers, the first circular wafer was processed by other means and then chamfering was performed, but this first circular processing step was eliminated and chamfering was performed directly. As a result, work efficiency can be improved.

[Effects of the Invention] According to the present invention, it is possible to provide a semiconductor wafer processing method and a processing apparatus that improve wafer processing accuracy and grindstone life.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a main part of an embodiment of the semiconductor wafer processing apparatus of the present invention, FIG. 2 is a plan view and longitudinal sectional view of a boat method compound wafer, and FIG. 3 is a longitudinal sectional view of a main part of a conventional processing apparatus. Fourth
The figures are a plan view and a longitudinal cross-sectional view of the wafer before and after chamfering. DESCRIPTION OF SYMBOLS 1... Wafer, 2... Copying model, 4... Drive shaft, 5... Roller, 6.7. g...Whetstone. Agent Patent Attorney Susuki 1) Toshiyuki Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a semiconductor wafer processing method in which a grindstone for grinding a wafer attached to a mounting part is driven according to a copying model that determines the processing shape of the wafer and grinds the wafer, a rough grinding wheel for rough processing and a chamfering process are performed on the grindstone. A semiconductor wafer processing method, comprising: grinding the wafer with the rough grinding wheel, moving the wafer to a processing surface of the finishing wheel, and chamfering the wafer with the finishing wheel. . (2) Attach a copying model and a chucking portion for attaching a wafer to the copying model drive shaft, attach a roller and the wafer grinding wheel to the grindstone drive shaft, move the roller to the copying model to bring it into contact with the copying model, and In a semiconductor wafer processing apparatus that drives a grindstone to grind the wafer into the same shape as the copy model, a rough grinding wheel for rough processing and a finishing grindstone for chamfering are connected and provided on the grindstone drive shaft, and the rough grinding wheel is connected to the grindstone for rough processing. A semiconductor wafer processing device characterized by being capable of continuous processing of chamfering and chamfering.