JPH0462244B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an apparatus for slicing semiconductor wafers from semiconductor ingots such as single crystal silicon ingots.

[Background of the invention]

The technology for obtaining wafers by slicing single-crystal silicon ingots requires slicing them as thinly as possible because the materials are expensive and the products are thin, about 0.25 to 0.3 mm thick. For this reason, the cutting wheel for slicing must be made as thin as possible, but the diameter of single-crystal silicon ingots continues to increase due to improvements in manufacturing technology, and the diameter of a regular disc-shaped cutting wheel is As the size increases, the grinding wheel must be made thicker to maintain its rigidity, resulting in a lower yield. For this reason, conventional devices of this type
A diamond grinding wheel with an inner peripheral blade as shown in Fig. 8 and Fig. 8 is used. That is, in FIGS. 7 and 8, reference numeral 1 denotes an inner cutting wheel having an inner diamond grinding wheel blade 1a formed thereon, and the outer periphery of the grinding wheel is fixed to the grinding wheel support ring 2 in a tensioned state. The grinding wheel support ring is rotatably supported by a bearing 3, and while the grinding wheel support ring 2 is rotated at high speed, a wafer is sliced from the single crystal silicon ingot 4 by the diamond grinding wheel blade 1a on the inner circumference. There is.

According to this configuration, it is possible to reduce the wall thickness of the cutting wheel 1, but on the other hand, since the cutting wheel has an internal peripheral blade, the outer diameter of the cutting wheel, in other words, the diameter of the grinding wheel support ring 2 can be reduced. As the diameter becomes larger, larger equipment is required, and recently, as mentioned above, the diameter of single crystal silicon ingots has become larger, while the outer diameter has increased to about 200.
mm is now being produced, and as a result, equipment is becoming larger and larger, and countermeasures are required.

[Purpose of the invention]

The present invention has been made in response to the above-mentioned demands, and provides a novel semiconductor wafer slicing device that is a small disk-shaped cutting wheel that cuts at the outer periphery and can slice at a high yield. The purpose is to

[Summary of the invention]

The thickness of the semiconductor wafer is approximately 0.5 to 0.7 mm, and it can be elastically deformed relatively easily, albeit slightly. Focusing on this point, the present invention gradually thins the outer circumferential side of the required thin disk-shaped cutting wheel, and as the cutting progresses, the semiconductor wafer is elastically deformed in the direction away from the ingot, thereby achieving high rigidity. This enables high-yield slicing using a disc-shaped cutting wheel.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is a schematic diagram showing the basic configuration of a slicing device according to the present invention. In the figure, reference numeral 10 is a disc-shaped cutting wheel with a wall thickness of 5 to 10 mm having a desired rigidity, one side of which remains flat, and the outer peripheral side of the other side with a semiconductor. The outer periphery of the grinding wheel is made gradually thinner by forming an inclined surface 10a that follows the elastic deformation of the wafer, and at the end, a flat plate with a parallel cross section over the required width and a thin wall with a thickness of about 0.2 to 0.4 mm is formed. A portion 10b is formed, and diamond abrasive grains are fixed to the outer peripheral edge of the portion 10b to form a grindstone blade 10c. The diamond abrasive grains may be fixed directly to the grinding wheel, or a segment-shaped grindstone formed in advance may be fixed to the grinding wheel by gluing, brazing, or the like.

Further, the apparatus of the present invention is provided with means 5 for elastically deforming the semiconductor wafer 4a to separate it from the ingot 4 as cutting progresses. This elastic deformation means may have any configuration, but for example, as shown in FIG. 2, an air chuck 6 is attracted to the cutting start end of the wafer, and the air chuck is set as the cutting progresses using a screw, an electric motor, etc. Pull it in the direction of the arrow X by the length that you have. In addition, in Fig. 1, 7 is the shaft of the grinding wheel, and 8 is the shaft of the grinding wheel.
is its bearing part.

Since the semiconductor wafer slicing apparatus of the present invention has the above-described configuration, it can slice with a high yield even though it is a thick disc-shaped cutting grindstone as described below.

That is, FIG. 2 is an explanatory diagram showing the initial stage of cutting, and shows a state in which the wafer 4a is cut out by the flat thin part 10b.After reaching this state, as the cutting progresses, the air chuck 6 is gradually moved in the direction of the arrow X.
The wafer is elastically deformed by being pulled in the direction of the wafer. In addition,
In FIG. 2, reference numeral 9 denotes a stopper block for preventing destruction upon completion of cutting, and has a curved surface 9a formed above the surface in contact with the single crystal silicon ingot 4 to allow elastic deformation of the wafer.

FIG. 3 is an explanatory diagram showing the state of supply of grinding fluid during cutting. In the present invention, since the wafer is cut using a grinding wheel, it is natural to cut the wafer while supplying a grinding fluid between the side surface of the grinding wheel and the inner surface of the wafer. When the grinding fluid is supplied to the side of the grinding wheel using the special nozzle of the pending patent application (Japanese Patent Application No. 145340/1982), the grinding fluid adheres to the side of the grinding wheel and flows as shown by arrow B in Fig. 3. The grinding fluid reaches and is supplied between the side surface of the grinding wheel and the inner surface of the wafer, and dynamic pressure is generated by the grinding fluid around the contact point A between the wafer and the inclined surface 10a of the grinding wheel, lifting the wafer from the side surface of the grinding wheel. It can be kept in a closed state. Therefore, the wafer can be cut without metal contact with the grinding wheel.

FIG. 4 is an explanatory diagram showing the state just before the end of cutting. As shown in the figure, since the wafer 4a is elastically deformed in the direction away from the ingot 4 while being cut,
Even with a thick disk-shaped cutting wheel, cutting can proceed without any support, and if a stopper block like this embodiment is used, the edge of the wafer will be cut when the cutting is completed despite the elastic deformation. There is no risk of parts being destroyed.

As described above, the disc-shaped cutting wheel used in the present invention has a thin wall portion 10b with a parallel cross section on its outer periphery, so there is a risk that the thin wall portion may vibrate during cutting.

FIGS. 5 and 6 show an example equipped with means for relieving the above phenomenon. That is,
In this embodiment, a large number of static pressure pockets 11a are provided on both sides of the thin wall portion 10b excluding the area where the ingot is cut.
A grinding wheel support plate 11 having a grinding wheel support plate 11 having a
0b is supported. In FIG. 5, 4' indicates the pre-cutting position of the silicon ingot, and 4'' indicates the cutting completed position.

〔Effect of the invention〕

As described above, according to the present invention, although it is a small device using a disc-shaped cutting wheel having a grinding wheel on the outer periphery, it has the effect of being able to perform slicing with an extremely high yield using a thin grinding wheel. be.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a semiconductor wafer slicing apparatus according to the present invention, FIG. 2 is an explanatory diagram showing the initial state of cutting, FIG. 3 is an explanatory diagram showing the supply state of grinding fluid during cutting, and FIG. Fig. 4 is an explanatory diagram showing the state just before the end of cutting, Fig. 5 is a front view showing the support structure of the cutting edge, Fig. 6 is a sectional view taken along the line A-A' in Fig. 5,
Figure 7 is a front view of a conventional internal grinding wheel;
The figure is a sectional view taken along the line B-B' in FIG. 7. DESCRIPTION OF SYMBOLS 10...Disc-shaped cutting grinding wheel, 10a... Inclined surface, 10b... Thin wall part, 10c... Grinding wheel blade, 5
(6,X)...Elastic deformation means.

Claims (1)

[Claims] 1 The outer periphery of one side of a thick disk-shaped cutting wheel with the required rigidity is made into an inclined surface that follows the elastic deformation of the semiconductor wafer, so that the outer periphery of the grinding wheel is gradually thinned and finally If the grindstone blade has a desired thin wall dimension and is provided with a means for elastically deforming the semiconductor wafer as cutting progresses, the elastic deformation enables slicing by the thick disk-shaped cutting wheel. A semiconductor wafer slicing device characterized by: