JP2646231B2 - Method and apparatus for cutting wafer from semiconductor material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer cutting method and apparatus for cutting a wafer from a semiconductor material such as a silicon ingot and then polishing the cut surface of the cut wafer. is there.

[Conventional technology]

An inner peripheral blade is widely used as a means for cutting a wafer from a semiconductor material such as a gallium arsenide ingot, a silicon ingot, and a gallium phosphorus ingot.

As shown in FIG. 6, this kind of inner peripheral blade is obtained by electrodepositing abrasive grains on the inner peripheral edge of a donut-shaped base 1 to form a cutting edge 2, and forming the cutting edge 2 on the outer peripheral edge of the base 1. In general, a plurality of holes 3 are arranged at equal circumferential positions and are used as mounting holes. This kind of inner peripheral blade 4 is attached to the holder 5 as shown in FIG. 5 with the cutting edge 2 tensioned by applying a tension F to the inner peripheral blade 4 outward in the radius using the hole 3. Is done. Then, with the inner peripheral blade 4 mounted, the holder 5 is rotated by using an appropriate driving means, and the semiconductor material 6 held by the ingot holding means is inserted into the center hole of the inner peripheral blade 4 to remove the semiconductor material 6. By cutting in the direction of the arrow, the semiconductor material 6 is cut.
Is performed, and a wafer is cut out. Normally, a suction table 7 that receives the cut wafer by suction is arranged inside the holder 5.

The cut wafer is taken out of the holder 5 by an appropriate means, and is cleaned and polished on the cut surface in the next step.

[Problems to be solved by the invention]

However, in the method of slicing the semiconductor material using the inner peripheral blade, the outer diameter of the inner peripheral blade is almost 1 m, so that there is a problem that the entire apparatus to which this is attached becomes larger. When cutting with the inner peripheral blade, the cutting edge must be attached to the holder 5 with tension in order to perform high-precision machining. As a result, the axial center is displaced due to the imbalance of the tension, and the cutting edge 2 is easily deformed, and the tension adjustment of the cutting edge 2 is very difficult. When the blade 2 is deformed, there is an inconvenience that machining accuracy is deteriorated.

Further, a suction table 7 for holding a wafer must be provided inside the holder 5, and the wafer sucked by the table 7 is taken out and sent to the next step. Center hole 8 of inner peripheral blade 4
And without touching the cutting edge 2, there are many limitations, which inevitably complicates the device configuration and limits the degree of freedom in device design.

By the way, the wafer 9 cut from the semiconductor material 6
As shown in FIG. 7 (a), since the cut surface is uneven, as shown in FIG.
When the surface is polished using a grinding wheel 11 while being suction-fixed to 10, even if the surface seems to be polished at first glance, when the suction of the chuck table 10 is released, as shown in FIG. Due to the springback, irregularities on the suction surface 9a side appear on the front surface side, so that the polished surface becomes irregular.

In order to eliminate such inconvenience, the semiconductor material 6
If the end surface of the wafer 9 is polished and flattened and then sliced, the cut flat surface of the wafer 9 is attracted to the chuck table 10 side, and the cut surface is polished. A flat and highly polished surface can be obtained.

From such a viewpoint, it has been proposed to separately provide a polishing grindstone for polishing the end face of the semiconductor material near the inner peripheral blade.

However, since the inner peripheral blade is originally a large device,
As shown by the dashed line in the figure, if the grinding wheel is provided outside the inner peripheral blade, there is a disadvantage that the apparatus becomes larger and larger. Therefore, from the viewpoint of minimizing the size of the apparatus as much as possible, the grinding wheel 11 is provided inside the holder 5, but this causes a disadvantage that the apparatus configuration becomes more complicated.

The present invention has been made in view of the above circumstances, and aims to reduce the size and simplification of the device, further increase the degree of freedom in device design, and improve both workability and processing accuracy. An object of the present invention is to provide a method and an apparatus for cutting a wafer from a semiconductor material that can be achieved.

[Means for solving the problem]

The present invention is configured as follows to achieve the above object. That is, the method for processing a wafer from a semiconductor material according to the present invention involves polishing the end face of the semiconductor material, cutting and moving the semiconductor material after the completion of the polishing, slicing the semiconductor material with a band saw, and cutting the wafer, while cutting the wafer. Sometimes, the wafer suction means facing the polished surface of the semiconductor material is linked to the cutting movement of the semiconductor material while maintaining the facing relationship with the polished surface, and the surface of the wafer cut by the band saw is polished to the suction surface. The wafer is held and held by the wafer suction means, and the cut surface of the band saw is polished by another polishing whetstone in this suction state, and a wafer cutting device from a semiconductor material of the present invention is provided. A first polishing wheel for polishing an end surface of a semiconductor material, and the first polishing wheel A band saw for slicing the semiconductor material whose one end surface has been polished by the cutting movement of the semiconductor material, and a polishing surface of the semiconductor material polished by the first polishing grindstone. In conjunction with the cutting movement, the wafer sawed from the semiconductor material by the band saw is adsorbed and held by using the polished surface as an adsorbing surface, and the cut surface of the wafer adsorbed by the wafer adsorbing device is polished by the band saw. The second polishing wheel is arranged on the cutting line.

[Action]

In the present invention configured as described above, the semiconductor material has its end face polished by a polishing grindstone (first polishing grindstone) arranged near the band saw, and after the end face polishing is completed, the cutting and moving movement of the semiconductor material is performed. The semiconductor material is sliced by a band saw. Then, each time one wafer is cut, the end face of the semiconductor material is polished. By repeating this end face polishing and slicing, wafers whose one end face is polished are cut out of the semiconductor material one after another.

At the time of slicing the semiconductor material, the wafer suction means facing the polished surface of the semiconductor material keeps the facing relationship and interlocks with the cutting and feeding movement of the semiconductor material, and the wafer cut by the band saw has the polished surface. The wafer is suctioned by the wafer suction means, and the cut surface cut by the band saw in this suction state is polished flat by a second polishing wheel.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an apparatus configuration showing an embodiment of the present invention. The apparatus shown in FIG. 1 shows a portion where the semiconductor material held by the ingot holding means is sliced after the end face is polished.

In the figure, a semiconductor material 6 such as a silicon ingot is shown.
The band saw 12 is formed by forming abrasive grains on the edge of a band-shaped substrate 13 made of steel, stainless steel, or the like by electrodeposition or the like to form the cutting edge 2.

The band saw 12 is hung between a driving pulley 14 and a driven pulley 15 and travels between the two pulleys 14 and 15. And
In the vicinity of the band soap 12, a grinding wheel 16 is rotatably provided by driving a motor (not shown). The arrangement relationship between the band saw 12 and the grinding wheel 16 is as follows.
For example, as shown in FIG. 2, a polishing grindstone 16 may be provided on the upstream side of the production processing line, and a band saw 12 may be provided on the downstream side. Conversely, as shown in FIG.
12 may be provided, and a grinding wheel 16 may be provided on the downstream side. In this case, in any case, an adsorption table 19 for adsorbing and holding a wafer cut from the semiconductor material 6 is provided on the opposite side of the band saw 12 so as to oppose the semiconductor material 6 so as to interlock with the cutting movement of the material 6. It is.

In the case of the arrangement shown in FIG. 2, first, the end face of the semiconductor material 6 is polished by the polishing wheel 16 rotating at the upstream position. If the semiconductor material 6 is sent in the downstream direction after the end face polishing is completed, the semiconductor material 6 is cut by a band saw, and the cut wafer is adsorbed to the suction table 19 from the polished surface side and collected, and is then recovered. Conveyed to the process.

When cutting the semiconductor material 6, if the polishing surface 16a of the polishing grindstone 16 is shifted forward (left side in the figure) by the thickness t of the wafer from the end surface 12a of the band saw 12,
After the semiconductor material 6 is polished, the semiconductor material 6 is moved to the downstream side in parallel with the polished surface 16a, so that the semiconductor material 6 is automatically sliced with a target wafer thickness.

After the completion of the slicing, the semiconductor material 6 is returned to the original upstream position, and subsequently fed forward (to the left in the drawing) to polish the end face by the polishing grindstone 16 to perform the next slicing. Move to

By repeating edge polishing and slicing in this manner, wafers having a predetermined thickness are cut out one after another.

Also, in the case of the arrangement shown in FIG. 3, at the upstream position,
The edge-polished semiconductor material 6 is cut by a band saw 12, and after the cutting is completed, the material 6 is sent to a downstream position, where the cut surface is polished by a polishing grindstone 16. After completion of the edge polishing, the semiconductor material 6
Moves back to the original upstream position. Then, the same material 6 is sent forward (to the left in the drawing) by the thickness of the wafer, and then sent to the band saw 12 to be sliced.

As described above, in each of the arrangements shown in FIGS. 2 and 3, after the end face polishing of the semiconductor material 6 is completed, the semiconductor material 6 is sliced, and the wafer is cut out.

As described above, since the end surface of the semiconductor material 6 is polished after the end surface of the semiconductor material 6 is polished, one surface of the cut wafer is always polished. Accordingly, the wafer can be suction-fixed using the polished surface as a suction surface, and the surface (cut surface) can be polished with a polishing grindstone. Therefore, even if the suction is released after polishing is completed, as shown in FIG. In addition, there is no possibility that "irregularities of the wafer suction surface 9a appear on the front side due to spring back", and thus the cut surface by the band saw 12 can be polished flat.

The tension of the cutting edge 2 of the band saw 12 is
This is achieved only by moving one (or both) of the members 5 in the outward direction (Z direction in FIG. 1) with respect to the center axis, and at the same time, the cutting edge 2 is deformed by an uneven force when adjusting the tension. The workability of the tensioning of the cutting edge is greatly improved.

Furthermore, since the diameter of the pulleys 14 and 15 on which the band saw 12 is hung can be sufficiently smaller than the diameter of the inner peripheral blade of the conventional example,
The size of the apparatus can be significantly reduced as compared with a cutting apparatus using an inner peripheral blade. In addition, since the device configuration is simple, the cost of the device can be reduced, and the economic benefit is large. In addition, since a wide range of free space is formed near the band saw 12, the polishing grindstone 16 and the recovery device for the wafer 9 can be disposed in the free space in an arbitrary manner, so that the degree of freedom in device design is increased. In addition, the configuration of the apparatus and the arrangement of the apparatuses can be optimally set according to the state of the cutting line.

Further, the cutting edge 2 of the band saw 12 and the grinding wheel 16 can be easily set in parallel due to the configuration of the apparatus, and this is desirable in terms of improving the processing accuracy and processing efficiency of polishing.

In general, the band saw 12 has an advantage that the device configuration is simple and the device can be reduced in size. However, the cut surface is rougher than the inner peripheral blade. As shown in b), when the surface is polished by suction with the chuck table 10, there is a drawback that the roughness of the adsorption rough surface appears larger on the polished surface due to springback due to the coarseness. It is not used as a cutting device.

In the present embodiment (the present invention), the band saw 12 is combined with a polishing grindstone 16 and the end face of the semiconductor material 6 is polished and then cut. By eliminating the drawback that the side irregularities appear greatly) and by carrying out the various advantages of the band saw 12, it is possible to provide a device that is superior to the proposed device in which the inner peripheral blade is combined with a grinding wheel. Will be possible.

FIG. 4 shows an embodiment apparatus from polishing of the end face of the semiconductor material 6 to polishing of the cut surface through slicing. As described in the examples of FIGS. 1 to 3, this apparatus is configured to perform the edge polishing of the semiconductor material 6 and then to slice the same. Then, a dedicated grinding wheel for grinding the cut surface of the cut wafer is provided, and the cutting of the wafer and the polishing of the cut surface of the wafer are continuously performed on-line for cutting.

In FIG. 4, a first polishing wheel 16 is provided on the upstream side of the cutting line, and a band saw 12 is provided on the downstream side. After the end surface polishing of the semiconductor material 6 is performed by the first polishing wheel 16, The same material 6 is sliced by the band saw 12, and the wafer 9 is cut out. This wafer 9
At the time of cutting, the suction table 19 as a wafer suction means faces the polishing end face of the semiconductor material 6 with the band saw 12 interposed therebetween, and as the material 6 moves in the cutting direction, the suction table 19 also moves to the polishing surface of the semiconductor material 6 (polishing). (The end face) and cooperates in the same direction while maintaining the facing relationship, so that the cut wafer is securely held by suction without dropping.

At a position further downstream than the band saw 12, a second grinding wheel 17 is provided rotatably by driving a motor (not shown). The wafer 9 cut out by the band saw 12 is adsorbed on the adsorption table 19 with the surface polished by the first polishing wheel 16 as an adsorption surface, and moved by the movement of the table 19 to the polishing position of the second polishing wheel 17. It comes. Then, the cut surface of the wafer 9 by the band saw 12 is polished by the second polishing grindstone 17.

When the cut surface is polished, the surface (cut surface) of the wafer 9 is polished by the second polishing grindstone 17 because the surface which has been polished flat is adsorbed on the adsorption table 19 as described above. After that, even if the suction of the wafer 9 is released, the irregularities on the suction surface side due to the springback do not appear on the front surface side, and the wafer 9 is flattened on both sides by the polishing whetstones 16 and 17. Polished.

After the polishing by the second polishing wheel 17 is completed, the wafer 9 is delivered to the transfer suction table 18 at a downstream position, and transported to a desired process position such as cleaning.

As described above, in this apparatus, the cutting of the wafer and the polishing on both sides of the cut wafer are continuously performed on the cutting processing line, and the effect that the processing process of the wafer 9 is made more efficient is obtained. .

The present invention is not limited to the above-described embodiment, but can take various embodiments. For example, the grinding wheels 16, 17 are not limited to wheel types, but may be belt types. Further, a grinding wheel may be fixed to the surface of the band saw by means such as electrodeposition, so that the band saw itself has a polishing function.

〔The invention's effect〕

Since the present invention is configured so that a semiconductor material is sliced by a band saw, the apparatus configuration can be simplified and the apparatus can be reduced in size as compared with an apparatus using an inner peripheral blade, and the apparatus cost can be reduced. I can do it. Further, since the degree of freedom in designing the apparatus can be increased, the apparatus can be designed in an optimum form according to the situation of the cutting line. In addition, a device using an inner peripheral blade requires a complicated procedure for taking out a sliced wafer from the inside of the device, but the method using the band saw of the present invention eliminates the need for this complicated procedure. Speeding up can be achieved and work efficiency can be increased.

Also, since the semiconductor material is always sliced after the end surface is polished, when the cut surface of the cut wafer is polished, the polished surface is adsorbed by the wafer suction means. Is performed, after the polishing of the surface (cut surface) is completed, the conventional inconvenience that the unevenness of the suction side surface appears on the surface side due to the springback phenomenon can be reliably prevented, and the flat surface with good accuracy over both surfaces of the wafer can be prevented. A polished surface will be obtained.

In polishing the cut surface of the wafer, a dedicated polishing grindstone (second polishing grindstone) for performing the polishing, a first polishing grindstone for polishing the end face of the semiconductor material, and a band saw for cutting the semiconductor material after the end face polishing are used. And, by arranging it on a cutting processing line with a wafer suction means for sucking and holding a wafer cut by this band saw, end surface polishing of a semiconductor material and polishing of a slice and a cut surface of a cut wafer are continuously performed. This can greatly increase the efficiency of the wafer processing process. Moreover, the cut surface is polished in a state where it is adsorbed by the wafer adsorbing means for adsorbing the wafer cut from the semiconductor material, that is, the wafer is transferred from the adsorbing means of the cut wafer to a suction chuck or the like dedicated to polishing. The wafer suction means for sucking the cut wafer is cut off in conjunction with the cutting movement while maintaining the facing relationship with the polished surface of the semiconductor material. Since the wafer is configured to be adsorbed, the cut wafer can be surely adsorbed and held at the correct position (center position) regardless of the diameter of the semiconductor material, thereby enabling the next cut surface to be polished. It can be performed stably.

[Brief description of the drawings]

FIG. 1 is a perspective structural view showing a specific embodiment of a wafer slice portion of the apparatus of the present invention. FIGS. 2 and 3 are explanatory views showing an example of the arrangement of a band saw and a grinding wheel in the embodiment. FIG. 1 is an explanatory view showing an embodiment of the overall configuration of the apparatus of the present invention, FIG. 5 is a cross-sectional view showing an apparatus for cutting a semiconductor material using an inner peripheral blade, and FIG. , Seventh
The figure is an explanatory view showing a polishing mode of a cut surface of a wafer cut out from a semiconductor material. 1 ... base, 2 ... cutting edge, 3 ... hole, 4 ... inner peripheral blade,
5 Holder, 6 Semiconductor material, 7 Suction table, 8 Center hole, 9 Wafer, 9a Suction surface, 10
…… Chuck table, 11… Abrasive whetstone, 12 …… Band saw, 12a …… End face, 13 …… Substrate, 14 …… Drive pulley, 1
5: driven pulley, 16: grinding wheel (first grinding wheel), 17: second grinding wheel, 18: suction table for conveyance, 19: suction table.

Claims (2)

(57) [Claims] An end surface of a semiconductor material is polished, and after the polishing is completed, the semiconductor material is cut and moved and sliced by a band saw to cut out a wafer. On the other hand, when a wafer is cut out, the wafer is opposed to the polished surface of the semiconductor material. The wafer suction means is held by the wafer suction means while maintaining the facing relationship with the polished surface in conjunction with the cutting movement of the semiconductor material, and the wafer cut by the band saw is polished with the surface on the side being polished as the suction surface,
A method for cutting a wafer from a semiconductor material, wherein a cut surface of the band saw is polished by another polishing grindstone in this suction state. 2. A first grinding wheel for polishing an end surface of a semiconductor material, a band saw for slicing a semiconductor material whose one end surface is polished by the first grinding wheel by cutting and moving the semiconductor material, The wafer cut out of the semiconductor material by the band saw is interlocked with the cutting movement of the semiconductor material while maintaining the opposing relationship while maintaining the opposing surface, and the wafer is suction-held with the polished surface as the suction surface. And a second polishing grindstone for polishing a cut surface of the wafer adsorbed by the wafer adsorbing means by the band saw, which is arranged on a cutting line, from a semiconductor material. Wafer cutting machine.