JPH07302774A - Polishing of semiconductor substrate, device thereof and semiconductor substrate polishing use applying plate - Google Patents

Abstract

PURPOSE:To stabilize polishing of substrates, to lessen the thickness unevenness within the surfaces of the substrates and to prevent an unpolished part from being generated even if the number of the sheets of the substrates on an applying plate is increased or even the large-diameter substrates and the substrates applied on the inside of the substrate applying surface of the applying plate. CONSTITUTION:One groove or two grooves or more of the form of concentric circles with a polishing use applying plate 12 are formed in the opposite surface to a substrate applying surface 11 of the plate 12. A plurality of pieces of holes 9 to penetrate to the surface 11 are provided in each bottom of the grooves 8. When a polishing agent 6 is fed in the grooves 8 formed in the plate 12, which makes a relative motion with a surface plate 3, through a feed opening 7, the agent 6 passes through the holes 9 provided in the bottoms of the grooves through the grooves 8 and comes flowing out on the surface 11. Accordingly, the agent 6 can be fed also from the inside of a gap between the surface plate 3 and the plate 12 and the agent 6 can be evenly fed from the center of the gap extending over the outer periphery of the plate 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor substrate polishing method in which a plurality of semiconductor substrates are attached to a plate and polished.
The present invention relates to the apparatus and a polishing sticking plate used in a method for polishing a semiconductor substrate.

[0002]

2. Description of the Related Art In general, a semiconductor substrate used for electronic devices and optical elements is cut into a predetermined thickness from a single crystal, and at least one surface thereof is mirror-finished by polishing and put into a device manufacturing process. Is.

As a method of polishing a semiconductor substrate, there are a double-sided polishing method in which both surfaces are simultaneously polished and a single-sided polishing method in which one surface is sequentially polished. In the single-sided polishing method, a plurality of semiconductor substrates are attached to a circular polishing attachment plate using wax, and the surface plate of the polishing apparatus or the polishing cloth attached to the surface plate and the above-mentioned semiconductor substrate are attached. The polishing agent is made to face each other, a polishing agent is flown on the surface plate or the polishing cloth, and polishing is performed while applying pressure to the polishing sticking plate. The sticking plate is fixed to one place on the surface plate by a pressure cylinder, and rotates along with the rotation of the surface plate. As the abrasive, alumina abrasive grains are used in lapping, and colloidal silica or hypochlorite is used in polishing.

A plurality of semiconductor substrates are attached to one attaching plate, but in industrial production, it is required to attach as many sheets as possible in order to improve productivity. However, considering the handling property, there is a limit to increase the size of the sticking plate, and thus the interval between the sticking substrates has been narrowed, or double or more sticking has been performed (multi-row sticking). ).

FIG. 3 shows a conventional single-side polishing type polishing apparatus. Circular polishing sticker plate 2
A plurality of semiconductor substrates 1 are attached to the substrate attachment surface in a row in the circumferential direction using wax, and the polishing cloth 4 attached to the surface plate 3 of the polishing apparatus and the semiconductor substrate 1 are opposed to each other. The abrasive 6 is supplied from the supply pipe 7 to the center of rotation of the surface plate 3, the abrasive 6 is radially flown onto the polishing cloth 4 by the cone 10 for dispersing the abrasive, and the pressing plate 5 is applied to the polishing sticking plate 2 by the pressure cylinder 5. Polish while applying pressure.

Further, in general, the supply of the polishing agent is synchronized with the operation of the polishing apparatus, that is, the rotation of the platen, and the polishing agent compounded under a predetermined condition in advance is pumped at the same time as or slightly earlier than the rotation of the platen. It is pumped up and supplied on a surface plate or a polishing cloth. The supply position of the abrasive is a know-how, and there is no particular one.
It is supplied to the center of rotation of the surface plate as shown in (a) and (b) or is supplied from the upstream side of the sticking plate 2 with respect to the rotation direction of the surface plate as shown in (c) and (d). Often.

[0007]

However, the conventional technique has the following problems. As described above, when the number of substrates on the sticking plate increases, the vicinity of the outer periphery of the sticking plate can always be in contact with the supplied polishing agent, but the polishing agent is less likely to be supplied to the vicinity of the center. Further, there is a large speed difference between the vicinity of the outer periphery and the vicinity of the center of rotation, that is, a great difference also occurs in the polishing speed. Therefore, in the large-diameter substrate or the substrate attached to the inside, there are problems that the thickness unevenness in the substrate surface becomes large, or an unpolished portion occurs.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to stabilize the polishing in the vicinity of the center of the sticking plate, a method for polishing the semiconductor substrate, and a sticking for polishing the semiconductor substrate. To provide the plate.

[0009]

A method of polishing a semiconductor substrate according to the present invention comprises a platen and a polishing attachment plate having a plurality of semiconductor substrates attached to each other with the semiconductor substrate interposed therebetween. In the method of polishing the surface of a semiconductor substrate by supplying an abrasive to the gap between the plate and the polishing sticking plate and relatively moving them while applying pressure to the surface plate and the polishing sticking plate. It is supplied from the outside as well as from the inside of the gap between the polishing sticking plate.

As a method of supplying the abrasive, it is common to supply the abrasive pumped up by a pump through a supply passage. In order to move the platen and the polishing sticking plate relative to each other, it is common to provide the platen rotatably and use a planetary gear mechanism or the like that works in conjunction with the rotation. In order to apply pressure between the surface plate and the polishing sticking plate, it is general that the upper and lower positions of the surface plate are fixed and the polishing sticking plate is pressed in the direction of the surface plate. To supply the abrasive from the inside of the gap between the surface plate and the sticking plate formed by the thickness of the semiconductor substrate, make a hole in the surface plate or the polishing sticking plate, and then remove the abrasive from this hole. It is performed by pouring it into the above gap.

The semiconductor substrate polishing apparatus of the present invention comprises:
A circular polishing sticking plate for laminating a plurality of semiconductor substrates on the surface of a lapping plate and a substrate sticking surface,
A polishing sticking plate having one or more grooves concentric with the polishing sticking plate on the surface opposite to the substrate sticking surface, and a plurality of holes penetrating the substrate sticking surface at the bottom of the grooves. And a supply system that supplies the abrasive from the outside of the gap between the polishing sticking plate and the surface plate and also supplies the abrasive from the groove of the polishing sticking plate, and a pressure is applied between the surface plate and the polishing sticking plate. It is provided with a pressing means and a means for relatively moving the platen and the polishing sticking plate.

The polishing sticking plate of the present invention is a circular polishing sticking plate used when a plurality of semiconductor substrates are stuck to a substrate sticking surface and the semiconductor substrates are polished. The surface has one or more grooves concentric with the polishing sticking plate, and a plurality of holes penetrating the substrate sticking surface at the bottom of the grooves.

The polishing sticking plate is preferably made of stainless steel or glass in addition to alumina ceramics.

[0014]

In the method of the present invention, when the polishing agent is supplied between the polishing sticking plate and the platen, the polishing agent is also supplied from the inside of the gap between the platen and the polishing sticker plate. It is possible to uniformly supply the polishing agent from the center of the gap to the outer periphery, and it is possible to prevent uneven polishing on the semiconductor substrate.

Further, in the apparatus of the present invention, when the polishing agent is supplied from the supply system to the groove of the polishing sticking plate which moves relative to the surface plate, the polishing agent is discharged from the groove to the substrate sticking surface through the hole at the bottom of the groove. Come on. Therefore, it is possible to uniformly supply the polishing agent only by making the grooves and holes in the plate.

Further, the plate of the present invention is used when a plurality of semiconductor substrates are adhered to this substrate adhering surface to polish the semiconductor substrates, and if an abrasive is supplied to the grooves, the holes at the bottoms of the grooves are removed from the grooves. Through it, an abrasive can be supplied near the center of the plate.

As described above, according to the present invention, in any case, since the polishing agent is directly supplied to the vicinity of the center of the sticking plate, even if the number of substrates on the sticking plate increases, the polishing agent will not be near the outer circumference of the sticking plate. Similarly, it can be kept in constant contact with the abrasive. Therefore, even in the case of a large-diameter substrate or a substrate attached to the inside, uneven thickness in the surface of the substrate or an unpolished portion does not occur.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view and a cross-sectional view showing a semiconductor substrate polishing apparatus of this embodiment.

The semiconductor substrates 1 are attached in a row in the circumferential direction to an attachment plate 12 made of alumina ceramics with a wax (not shown). The sticking plate 2 is placed on the surface plate 3 so that the semiconductor substrate 1 stuck on the sticking plate 2 faces the polishing cloth 4 stuck on the surface plate 3 of the polishing apparatus. Although not shown in the illustrated example, the surface plate 3 is actually used.
A plurality of sticking plates 12 are placed on the upper side along the circumferential direction so that a large number of semiconductor substrates can be simultaneously polished. The semiconductor substrate 1 is pressurized to a predetermined pressure by the pressure cylinder 5 via the attachment plate 12.

On the surface (upper surface in the illustrated example) opposite to the substrate sticking surface 11 of the sticking plate 12, the sticking plate 12 is provided.
A groove 8 concentric with is provided. The position of the groove 8 is near the center of the position where the substrate is not attached. A hole 9 for an abrasive is provided at the bottom of the groove 8 and penetrates the substrate attachment surface 11. The depth of the groove 8 is 1/2 of the thickness of the sticking plate 12, and the cross section is semicircular.

If the groove depth is too deep, the strength of the adhesive plate 12 will be reduced, and even if the cross section has a corner, stress concentration may occur at that point. A cross-sectional shape is desirable. The diameter of the through hole 9 is about 2/3 of the width of the groove 8, and the number of grooves is 8 along the groove bottom at equal intervals. If the diameter of the through hole 9 is small, the polishing agent is not sufficiently supplied.
It is desirable that the groove width be less than or equal to.

The polishing agent 6 is fed by a pump (not shown) and supplied onto the polishing cloth 4 from the supply pipe 7 in two directions. One is supplied to the outer peripheral side of the substrate 1 from the outside of the gap between the surface plate 3 and the sticking plate 12 through the center of the surface plate 3 as shown by the arrow in the figure, and the other is supplied to the groove 8 provided in the sticking plate 12. Is supplied to the inner peripheral side of the substrate 1 to contribute to polishing.
Here, the outer peripheral side of the substrate 1 refers to a portion located on the outer peripheral side of the sticking plate 12, and the inner circumferential side of the substrate 1 refers to a portion located on the center side of the sticking plate 12.

In the conventional example, since the supplied polishing agent is supplied only to the outer peripheral side of the substrate, the supply to the inner peripheral side becomes insufficient. However, in this embodiment, at the same time as the supply of the polishing agent to the outer peripheral side, the polishing agent supplied to the groove 8 is also supplied to the inner peripheral side of the substrate 1 inside the sticking plate 12 through the through hole 9 and to the outer peripheral side. Similar polishing is performed. In this embodiment, no abrasive dispersion cone is required.

Polishing was performed by using the apparatus according to the above-mentioned embodiment. Eight GaAs substrates with a diameter of 76 mm and a diameter of 36
It was attached to a 0 mm attachment plate. The pressure during polishing was 100 g / cm ² , the rotation speed of the platen was 50 rpm, hypochlorite was used as the abrasive, and the supply rate was 300 ml / min.
Polishing was performed for 0 minutes. After polishing TTV (Total Thicknes
s Variation) was measured, the center of the substrate tended to be slightly convex, but the average value of 8 sheets was 1.5 μm. In addition, a very good mirror surface was obtained. Figure 3 under the same conditions
In the conventional method shown in (1), the average value was 2.1 μm, and although there were no unpolished portions, the side located on the outer periphery was largely polished, which was a so-called one-sided shape.

FIG. 2 shows another embodiment of the present invention. Diameter 3
14 pieces of GaAs substrates having a diameter of 2 inches were doubly stuck to the sticking plate 22 of 00 mm, that is, 10 pieces were stuck on the outside and 4 pieces were stuck on the inside. On the attachment plate 22, two concentric circular grooves 8 similar to those in the above-described embodiment are provided so as to avoid the attachment position, and twelve through holes 9 are provided. When polishing was performed under the same polishing conditions as in the above example, in the conventional method,
All of the four substrates attached to the inside did not become a mirror surface because they were unpolished, whereas in the method of this example, all 14 substrates could obtain good mirror surfaces.

[0026]

According to the method of the present invention, since the polishing agent is supplied from the inside of the gap between the surface plate and the attachment plate, the polishing agent can be supplied uniformly to all the semiconductor substrates. Thus, the flatness of the substrate can be improved. Also,
Even in multi-row attachment such as double-attachment, it is possible to prevent the generation of an unpolished portion and obtain a good mirror surface. Furthermore, the polishing yield and productivity can be significantly improved.

According to the apparatus of the present invention, the abrasive is supplied from the supply system to the groove of the polishing sticking plate, and the abrasive is also supplied from the inside of the gap between the surface plate and the plate through the through hole at the bottom of the groove. Therefore, polishing in the vicinity of the center of the polishing sticking plate can be stabilized.

According to the plate of the present invention, if the abrasive is supplied from the groove provided in the pasting plate, it is easy to supply the abrasive to the central portion of the plate, which was difficult to supply from the outside of the plate. become.

[Brief description of drawings]

FIG. 1 is a partial plan view and a sectional view for explaining an embodiment of a semiconductor substrate polishing apparatus of the present invention.

FIG. 2 is a partial plan view showing another embodiment of the present invention.

3A and 3B are a partial plan view and a sectional view of a conventional semiconductor substrate polishing apparatus.

FIG. 4 is an illustration showing two conventional methods of supplying an abrasive.

[Explanation of symbols]

 1 Semiconductor Substrate 3 Surface Plate 4 Polishing Cloth 5 Pressurizing Cylinder 6 Abrasive 7 Supply Pipe 8 Groove 9 Through Hole 12 Sticking Plate 22 Sticking Plate

Claims (6)

[Claims] 1. A surface plate and a polishing attachment plate having a plurality of semiconductor substrates attached to each other so that the semiconductor substrates are interposed therebetween, and an abrasive is supplied to a gap between the surface plate and the polishing attachment plate. Then, in the method of polishing the surface of the semiconductor substrate by relatively moving these while applying pressure to the surface plate and the polishing patch plate, the abrasive is supplied from outside the gap between the surface plate and the polishing patch plate. At the same time, the method of polishing a semiconductor substrate is characterized in that it is also supplied from the inside. 2. A surface plate and a circular polishing sticking plate which is placed on the surface plate and sticks a plurality of semiconductor substrates to the substrate sticking surface, wherein the surface is opposite to the substrate sticking surface. A polishing sticking plate having one or more grooves concentric with the sticking plate, and a plurality of holes penetrating the substrate sticking surface at the bottom of the grooves, the polishing sticking plate and a surface plate And a supply system for supplying the abrasive from the outside of the gap between the polishing adhesive plate and the abrasive adhesive from the groove of the polishing adhesive plate, a pressurizing means for applying a pressure between the platen and the abrasive adhesive plate, An apparatus for polishing a semiconductor substrate, comprising: means for relatively moving a disc and a polishing sticking plate. 3. A circular polishing sticking plate used for sticking a plurality of semiconductor substrates to a sticking surface of a substrate and polishing the semiconductor substrate, wherein the surface opposite to the sticking surface of the substrate is concentric with the sticking plate for polishing. 1. A sticking plate for polishing a semiconductor substrate, which has one or two or more grooves, and has a plurality of holes penetrating the substrate sticking surface at the bottom of the grooves. 4. The semiconductor substrate according to claim 2, wherein the depth of the groove is 1/2 or less of the thickness of the polishing sticking plate, and the cross section of the groove is arcuate. A polishing apparatus or a polishing plate for polishing a semiconductor substrate according to claim 3. 5. The semiconductor substrate according to claim 2, wherein the diameter of the through hole at the bottom of the groove is not less than ½ of the groove width and not more than the groove width. Or a sticking plate for polishing a semiconductor substrate according to 3 or 4. 6. The polishing sticking plate is made of stainless steel,
It is made of alumina ceramics or glass, and the polishing apparatus for a semiconductor substrate according to any one of claims 2 to 5, or the polishing plate for polishing a semiconductor substrate according to any one of claims 3 to 5.