JPS58114849A - Grinder - Google Patents

Abstract

PURPOSE:To reduce the infection of a warp at the time of grinding of the surface of a semiconductor wafer, by grinding only a circumferential part of the wafer by a grinding disc having a smaller concave part than the wafer, in a grinder preventing the infection of the warp of the wafer at the time of grinding of the semiconductor wafer. CONSTITUTION:A cylindrical cave 7 which is concentric with a grinding disc 6 whose diameter is smaller than that of a wafer by approximately 2mm. is provided at the center of a circular grinding disc 6 made of either iron or glass. The wafer 10 is secured at the center of a circular supporting plate 8 by a vacuum chuck. When the wafer 10 is lowered vertically to the center of the cylindrical cave 7 of the rotating grinding disc 6 for touching, a circumferential part of the backside of the wafer 10 is brought into contact with the grinding disc 6 and only the circumferential part of the backside of the wafer 10 is ground.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a polishing apparatus, and particularly to a polishing apparatus for improving the polishing precision K and increasing the breakage of the wafer on the back surface of a wafer having a warp. Regarding HI equipment.

ICG I (gp1caxi*1ally) Summary of conventional technology and problems
When producing a groove having a Gr*vnhlnaulchange*ri*a or semi-well structure, after vapor phase epitaxial growth is performed on the well provided on the wafer, the excess ttm long layer on the surface of the groove is removed before the device process. The knee that flattens out is a must-see.

However, the wafers are warped in convex, concave, or curved shapes due to the heat generated by the ATM during growth, so in order to correct this warpage and increase yield, high pressure is applied to polish away the excess growth layer, or the excess growth layer is polished off. The method used is to heat and press snow onto a surface plate, fix it, and then polish it.

However, in epitaxial growth with strict halogenation, the 100 to 200 μmm edges of the wafer are
N grows, and the cross-sectional shape of the wafer becomes as shown in Figure *1.

*If such protrusions occur around the wafer, applying pressure will cause chips or cracks in the periphery, which is the 5B problem.To prevent this, the conventional method is to polish the backside of the wafer to remove the protrusions. is taken. However, conventional research 1)! In the case of i-, the grinding machine is in the form of a flat plate, so when polishing the back surface, the following gap occurs. Song! The diagram is
FIG. 3 is a cross-sectional view of a wafer showing a conventional process for a convexly warped wafer. Figure (a) shows the foreshadowing of the wafer warped into a convex shape by forming an epitaxially formed layer with a high density of halogen on a wafer provided with a well.

At this point, protrusions appear around the periphery of the sea urchin.

Figure 118 (b) shows the condition when the conventional grinder was used to polish the surface of the surface of the surface of the surface of the surface of the surface of the surface. Moreover, Ken III's @- changes depending on the amount of warp to the cube. The figure (·) shows the surface of the wafer being fixed by applying pressure, and the periphery of the wafer is prepared by surface grinding. 1M2 diagram (d)
1gl shows the state of the excess growth layer formed on the wafer at the end of polishing, and the surface of the area polished by back-polishing is still covered with polishing water, and the warpage during epitaxial growth is the result. The family is reflected in the work.

Further, FIGS. 8(&) to (d) are cross-sectional views of a wafer following a conventional polishing process for a wafer warped in a concave shape.

In this case, @mtkoyo C9 Eva on the back side of the wafer: 5
The protrusions around the wafer may not be removed, and even after polishing the excess growth layer, 1 drop of polishing water is applied to the center of the wafer.
There is a difference between 4 minutes and bacteria remaining.

In addition, with the conventional polishing iron, even after backside polishing, the wafer warpage greatly affects the accuracy and reproducibility of the wafer surface polishing, and the protrusions around the Ik111 of other wafers. There is also a method of using chamfering AI4JK as a method for removing the wafer, but it has drawbacks such as chipping of the wafer and introduction of defects.

There is also a method using an etch knob, but this requires a process of applying and removing the mask material, and has the disadvantage that the surface of the etch knob becomes rough.

(8) Purpose of the Invention The purpose of the present invention is to provide a polishing device which is advantageous for polishing the periphery of the wafer, which is necessary to improve the polishing of the wafer and the retention of the element. It is to be lent.

(4) Structure of the Invention The present invention provides a polishing device that has a polishing disk with a diameter smaller than that of a polishing disk. l! One part is provided, and the object to be polished is added to the polishing disk so that only the peripheral part of the object to be polished is polished.

(5) Example of the Invention The present invention will now be explained using an example of the invention. In this example, a method for manufacturing an element having a buried EGI structure will be described. FIG. 4 is a cross-sectional view of a wafer showing a part of the manufacturing process of the device.

10,000th place (circular silicone (Si) with soil surface of 100J)
Anisotropic etching is performed on the wafer 1 using a potassium hydroxide (KOH) solution to form a well 2 having a depth of 1 μm (FIG. 4(a)).

Next, in well 2, magnesia spinel, which is a monocrystalline material, is heated to form a 1 μm thick single crystal magnesia spinel/111g, and further trinomialized J(p
cla)ft doped material, silicon tetrachloride (8iC1)
As a raw material gas, a layer of 425μI of low impurity n+ type siJm4 with a thickness of lOμm is prepared, and then a layer of 425μI of low impurity n-type 81 51-th gas phase
Figure (b)). This nest, magnesia spinel pigeon 8 and Si
Pigeons 4 and 5 had an IA length on the substrate 1 other than the well 2, and were warped so that the adult eel pigeon was 1, and the size of the warp was f180 μm. Also, on the wafer Hatobe-cho, there was an inverted eel with a diameter of 40 to 50 μm as shown in the IT diagram.

- The w&b diagrams are a perspective view (b) and a cross-sectional view (bJ) of the mQ) bending device showing a part of the protrusion on the back side of the wafer in an embodiment of the present invention. The center of the circular probe 6, which confuses the crow, is 2 times larger than the diameter of the wafer.
A base 7 made of Japanese cedar and concentric with a base 6 that is 4% smaller than m+n is provided. In addition, the wafer support plate Btn Shenshin I of the sun, which is made of stainless steel, is such that the support plate 8 is moved upward, so that the support plate 8 or the vibrator 9 is fixed to the support plate. It is attached.

Polishing of the rkA side portion of the wafer surface is performed using this polishing apparatus as follows. The surface of the wafer IQ (7), rather the surface on the growth layer side, and the surface of the wafer support plate 8 are brought into contact with each other so that the centers of each are convergent, and are fixed using a vacuum chuck, etc., for approximately bor.
, the sun-shaped sky of the polishing plate 6 that rotates 1i111 at Pm @
When the support rod 9 housed on the support plate 8 is lowered onto the polishing plate 6 at step 7, the periphery of the back side of the wafer 10 contacts the polishing M116, and the periphery of the back surface of the wafer 10 contacts. At this time, Gc reference 2000 was used as the polishing #* & upper polishing 1M material. I removed the wafer from the support plate 8, cleaned it, and then heated and pressed it onto a surface plate for surface polishing to flatten the wafer. 11B, 4.6 is deposited by mechanochemical polishing. After polishing is completed, an element is formed on the instep of the well using a normal device process.

According to an embodiment of the present invention, when depositing the back side of a wafer, the quality layer is
Only the periphery of the 2-way wafer can be polished, which has the effect that other parts of the manufacturing process are not polished. This t-kome,
By polishing the extra growth layer on the surface of the sea urchin, the effect of warping on the polishing accuracy can be reduced, and reproducibility can be improved, resulting in an increase in yield.

No. 68! ! , I is the research II showing other examples of the main party.
The difference between this figure and Fig. 5 is that the t-circular two that extends up to 'F' provided on the polishing disk is
This point is a concave portion with a depth of about 1 mz. This example has the advantage that it prevents the left abrasive material from coming out from the center (Buru 4, Ken 11).

Incidentally, in the embodiment explained in FIG. ts5, the @shaft plate rotates, but the grinding plate I11 may be fixed and the wafer rotated.

Further, in this embodiment, it is common to grind circular pieces, but it is not necessarily necessary to grind objects with shapes such as square cedar or hexagons. However, the relative plowing between the temporary polishing w1 object and the polishing machine may be done by #*, left and right sliding motion or vibration instead of a single rotation. You can play around with the object being polished.

(6) Effects of the Invention According to the present invention, it is possible to polish only a partial range around the object to be polished, regardless of its warpage, so that reproducibility and yield can be increased by 1. .

[Brief explanation of the drawing]

Figure m1 is a cross-sectional view of the wafer after vapor phase epitaxial growth, Figure 2tA and Figure 8 are cross-sectional views of the wafer used in the conventional polishing process for wafers to reduce warpage, and Figure 4 is the cross-sectional view of the wafer after the wafer has been grown.
FIG. 3 is a cross-sectional view of a wafer showing a part of the l1ll fabrication process of an element having a GI structure Jk. #15 Figures (a) and (b) are a perspective view and a cross-sectional view of the polishing J11 apparatus in one embodiment of the present invention, and Figure 6 is a cross-sectional view of a polishing disk in another embodiment of the present invention. It is. 6 Grinding machine 7 Adjustment 8 Wafer support plate 10 Wafer No. 1 drawing ratio Z drawing No. 3 opening (j)
(ctl Figure 4 (α) ・5 (b) 5 (a) Figure 4 (α) ・5 (b)

Claims (1)

[Claims] In a grinding device including a grinding H disk, a concave portion smaller than the size of the 11th object to be ground is provided in the grinding disk, and the value grinder ** is brought into contact with the grinding HI disk to remove the 1st object to be ground. A polishing device characterized by polishing the peripheral part of the.