JPS6311962B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a pedestal used when cutting a single crystal wafer. Conventionally, methods using a scriber and methods using a dicer are known as methods for cutting single crystal wafers. The former method involves making scratches on the top surface of the wafer using a loaded diamond cutter and then cracking the wafer by applying pressure, but this becomes difficult when the wafer thickness exceeds 400 μm. On the other hand, in the latter case, there is no problem due to the thickness even when the wafer thickness is 400 μm or more, and the importance of this dicer method has increased with the recent trend toward thicker wafers. The general method of the dicer method is to adhere a polyimide film 3 onto a pedestal 1 made of unglazed ceramics or glass with an adhesive 2 such as wax, and then apply silicone on top of it with an adhesive 4. A known method is to bond the wafer 5 and then cut it into a predetermined size using a diamond wheel. The reason why the polyimide film is interposed between the silicon wafer and the pedestal in this case is as follows. In other words, when using a pedestal made of unsintered ceramics, if cutting is performed with the silicon wafer directly attached without intervening film, the tip of the diamond blade approaches the pedestal as the cutting progresses, and eventually comes into contact with it. This is because if this process is repeated, the abrasion loss of the diamond blade increases, and because the adhesion between the silicon wafer and the unglazed ceramics is poor, small pieces of the silicon wafer may peel off during cutting. Furthermore, if a pedestal made of glass is similarly used without intervening a film, the adhesion to the silicon wafer is good, but the glass will be damaged during cutting. Therefore, polyimide film is indispensable for conventional cutting methods, but conventional methods have the disadvantage that this film is expensive, can only be used once, and also hinders process simplification. . As a result of intensive research to overcome the above-mentioned drawbacks, the inventors have found that by using fluorine-mica ceramics, which can be machined, as the material for the pedestal, there is no need to use a film, and the process is simple and inexpensive. They discovered that it was possible to cut single-crystal wafers. The present invention was obtained based on the above findings, and the gist thereof is as shown in Figure 2.
The pedestal 7 used for cutting the single crystal wafer 6 is a ceramic cutting pedestal characterized in that the pedestal 7 is made of a fluorine-mica ceramic sintered body. The pedestal of the present invention is made of a sintered fluorine-mica ceramic with excellent machinability, so even if it repeatedly comes into contact with the diamond blade during use, there is little wear loss on the diamond blade, and the surface of the pedestal is It has the advantage that by polishing it after use, it eliminates the markings that occurred during the previous use, making it possible to reuse it. Considering the formability and sinterability during production, the pedestal of the present invention is made of a molded body whose main component is fluorine mica (A) (hereinafter abbreviated as (A)) with a particle size of 3 μm or less, with a fluorine content of 1 to 1.
It is preferable to use a sintered body (B) (hereinafter abbreviated as (B)) produced by embedding in 10% by weight refractory powder. In addition, a sintered body manufactured under the same conditions as (B) except that a sintering aid or reinforcing agent is added to (B) above in order to improve sinterability and mechanical strength. A cradle consisting of is also available.
Examples of additives containing sintering aids and reinforcing agents include (A) containing 5 to 60% by weight of a fluoride mixture (C) (hereinafter abbreviated as (C)); For tungsten disulfide with fluoride mixture 10-50% by weight
0.5 to 35% by weight of (D) (hereinafter abbreviated as (D)), alkali metal, zinc and/or alkaline earth metal oxide-phosphoric acid frit 10 to (A)
(E) containing 50% by weight (hereinafter abbreviated as (E))
and (F) containing 10 to 30% by weight of a fluoride mixture and 0.5 to 25% by weight of carbon powder to (A) (hereinafter referred to as
(F)). These (B), (C), (D), (E) and (F)
JP-A No. 55-136171 "Production method of fluorine-mica ceramic sintered body" and JP-A No. 56-17981, respectively.
``Production method of fluorine mica ceramic sintered body'', JP-A-56-37270 ``Fluorine-mica ceramic sintered body'', JP-A-56-37271 ``High-strength fluorine-mica ceramic sintered body''"Body" and Japanese Patent Publication No. 1983-
It is disclosed in Publication No. 69272 "Method for producing fluorine-mica ceramic sintered body". This will be explained below using Examples and Comparative Examples. Example Fluorine phlogopite (KMg ₃ Al−
Si ₃ O ₁₀ F ₂ ) To 80 parts by weight of the powder, 20 parts by weight of a mixed powder containing four types of fluorides as sintering aids in the molar ratio shown in the table was added, mixed wet, dried, and then heated under pressure.
A fluorine phlogopite sintered body was produced by pressure molding at 1 ton/cm ² into a shape of 150Φ×50 mm and firing by filling.

[Table] Filling is performed using a mixed powder consisting of 94 parts by weight of refractory powder alumina with a particle size of 10 μm or less, 3 parts by weight of aluminum fluoride, and 3 parts by weight of potassium fluoride.
The test was carried out under the conditions of 1050°C and a holding time of 4 hours. The obtained fluorine phlogopite sintered body was sliced into a shape of 130 Φ x 3 mm, which was used as a pedestal 7. The pedestal 7 was placed on a heater block set at a temperature of 150°C, and heated with wax 8. Diameter 4inch, thickness 500μm
After bonding the silicon wafer 6 to the surface of the pedestal,
The silicon wafer was cut into 5 mm squares using a 50 μm wide diamond blade. During cutting, no peeling or chipping of the silicon wafer occurred. When the adhesive strength between the cut silicon chips and the pedestal was measured using the push gauge method, the average value for 20 silicon chips was
It was 9.4Kg/ ^cm2 . Next, the pedestal is placed on the heater block again, the wax is melted, the silicon wafer is peeled off, and the surface of the pedestal is polished until there are no markings left by the diamond blade. I performed the above cutting operation as a stand, and was able to cut the silicon wafer in the same way as before without any problems. Comparative Example 1 A glass plate 1 having the same shape as the pedestal of the example was heated to
It was placed on a heater block set at 150℃, a polyimide film 3 was adhered to the surface of the glass plate with wax 2, and then the diameter was fixed with wax 4.
After gluing 4inch silicon wafer 5, 50μm
The silicon wafer was cut into 5 mm squares using a wide diamond blade. Although the silicon wafer did not peel or chip during cutting, the polyimide film was also cut, so if the same glass plate was to be reused, a new and different film had to be used. In addition, the adhesive strength between the silicon chip and the pedestal after cutting was measured in the same manner as in the example.
It was 5.2Kg/ ^cm2 . Comparative Example 2 Cutting was carried out under the same conditions as in Example except that the pedestal was an unglazed ceramic plate, but a small piece of the silicon wafer came off during cutting. In the above embodiments, only silicon wafers were shown as samples to be cut, but the scope of use of the pedestal of the present invention is not limited to this, and various types of samples that can be cut using conventional cutting methods, such as gallium wafers and gallium arsenide wafers, are Can be used to cut single crystal wafers. As described above, by using the pedestal of the present invention, single crystal wafers can be cut in a simple process and at low cost without interposing a polyimide film even if the thickness of the part to be cut is thick. It is extremely useful in the field of electronics technology.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing a wafer adhered to a conventional pedestal, and FIG. 2 is a longitudinal sectional view showing a wafer adhered to a pedestal according to the present invention.

Claims (1)

[Scope of Claims] 1. A ceramic cutting pedestal used for cutting a single crystal wafer, characterized in that the pedestal is made of a sintered fluorine-mica ceramic body. 2. The ceramic cutting pedestal according to claim 1, wherein the single crystal is silicon, gallium, or gallium arsenide.