JPH0847854A - Pressure plate and polishing device using it - Google Patents

Abstract

PURPOSE:To provide a polishing device which can uniform load distribution over a semiconductor wafer. CONSTITUTION:A pressure plate 4 in a polishing device is composed of a first plate 1 is composed of a first plate 1, attached at the center of its one surface with a pressure rod 3, a second plate positioned facing the first plate 1 and adapted to hold a semiconductor wafer 8, and a load distributing ring 11 located between the first and second plates 1, 2, for distributing a load applied upon the first plate and directed toward a base plate 5 before the load is transmitted to the second plate 2. With this arrangement in which the load applied around the center of the first plate 1 by the pressure rod 3 is distributed by the distributing ring 11 and then is transmitted to the second plate 2, and the load is uniformly applied over the semiconductor wafer 8 supported to the second plate 2, thereby it is possible to polish the semiconductor surface with a high degree of flatness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure plate and a polishing apparatus using the pressure plate, and more particularly to a technique capable of polishing a member to be polished such as a semiconductor wafer with high flatness.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, a semiconductor ingot such as a silicon wafer is obtained by slicing from a silicon ingot, and the surface flatness is set to several .mu.m or less by mirror polishing.

An example of a polishing apparatus for mirror-polishing a member to be polished such as a semiconductor wafer is, for example, published by the Industrial Research Committee, "1992 version VLSI manufacturing and test equipment guidebook" (issued on November 22, 1991). ) P20-P2
No. 3, published by Ohmsha, "LSI Handbook" (Showa 5
It is known that, as described in P238, etc., issued on November 30, 1997, a load is applied to a pressure plate holding a member to be polished and the load is pressed toward the base plate.

FIG. 5 is a sectional view showing such a polishing apparatus. As shown, the pressure plate 34 is
A semiconductor wafer (member to be polished) 38 positioned by the template 39 is held via a holding pad 40, and a pressure rod 33 of an air cylinder (not shown) is held.
The semiconductor wafer 38 is rotated while being pressed against the polishing cloth 43 of the base plate 35 by the pressing force caused by the stroke of the stroke, and at the same time, the polishing agent 45 is supplied to perform mirror polishing.

[0005]

However, in such a conventional polishing apparatus, since the pressing force of the pressure rod 33 acts on the central portion of the pressure plate 34, the peripheral portion near the central portion of the pressure plate 34. The load applied to the semiconductor wafer 38 has an uneven distribution due to slack or deformation toward the central portion. This makes it difficult to stably manufacture the semiconductor wafer 38 having a high flatness of several μm or less.

As the diameter of the semiconductor wafer 38 is increased and the flatness thereof is increased as in today's day, the deterioration of the flatness of the polished semiconductor wafer 38 is caused by the deterioration of the circuit pattern formed in the subsequent process. It is becoming a serious problem in terms of quality.

Therefore, an object of the present invention is to provide a technique capable of making a load distribution on a member to be polished uniform and polishing the member to be polished to a high flatness.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0009]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, the pressure plate according to the present invention is provided with a first plate having a pressure rod attached to the center of one surface thereof, and a first plate provided so as to face the first plate and holding a member to be polished. Load distribution which is provided between the second plate and the first plate and the second plate, and which distributes the load applied to the first plate by the pressure rod in the direction of the base plate and transmits the load to the second plate. And means.

In this case, the load distribution means may be an annular load distribution ring or a plurality of load distribution pins. This load distribution ring and load distribution pin
It is desirable to place it coaxially with the pressure rod.

In these cases, a tapered surface is formed below the second plate, and the tapered surface is held by the holding portion of the connecting ring fixed to the outer peripheral position of the first plate. It is possible to attach the plate to the first plate. At this time, connecting pins are attached to a plurality of locations on the outer peripheral surface of the first plate, and a connecting groove into which the connecting pin can enter is formed in the connecting ring in a substantially L shape from the upper end to the lower side. The second plate can be attached to the first plate by fitting the connecting pin into the connecting groove of the connecting ring holding the plate and rotating the connecting ring. It is preferable that the tapered surface and the connecting ring be in a non-contact state with a slight gap formed in a state of being pressed by the pressing rod.

Further, the polishing apparatus according to the present invention is constructed by using the pressure plate as described above.

[0014]

According to the above-mentioned means, the first pressure rod is used.
Since the load applied to the vicinity of the center of the plate of 10 is dispersed by the load distributing means and transmitted to the second plate,
The load applied to the member to be polished held on the plate is evenly distributed, and the member to be polished can be polished with high flatness. Thus, for example, when the member to be polished is a semiconductor wafer, it is possible to eliminate adverse effects on the circuit pattern formation in the manufacturing process of the semiconductor device and improve the yield of the semiconductor wafer.

Further, by arranging the load distribution ring and the plurality of load distribution pins coaxially with the pressing rod, it becomes possible to more surely make the load distribution of the member to be polished uniform.

Further, by using the connecting ring, the second
The plate can be easily attached to the first plate, and the work of attaching and detaching the member to be polished can be performed quickly and easily.

By disposing the tapered surface of the second plate and the connecting ring in a non-contact state during the polishing process, distortion of the second plate holding the member to be polished can be prevented in advance. Therefore, it becomes possible to stably manufacture a member to be polished that has been polished to a high degree of flatness.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing the essential parts of a polishing apparatus according to an embodiment of the present invention, FIG. 2 is a side view of a pressure plate by the polishing apparatus of FIG. 1, and FIG. 3 is a load distribution of the pressure plate by the polishing apparatus. It is a perspective view shown.

As shown in FIG. 1, the polishing apparatus of the present embodiment has a first plate 1 having a pressure rod 3 attached thereto.
And a pressure plate 4 including a second plate 2 provided so as to face the first plate 1, and a base plate 5 located below the pressure plate 4.
And Both the pressure plate 4 and the base plate 5 are independently rotatable by a rotation driving means (not shown).

The pressure rod 3 attached to the center of the upper surface of the first plate 1 made of, for example, iron is vertically stroked by sliding of a piston of an air cylinder (not shown). The stroke of the pressure rod 3 presses the pressure plate 4 toward the base plate 5 with a force of several hundred kg.

At a plurality of locations on the outer peripheral surface of the first plate 1, connecting pins 7 to which the second plate 2 is attached are attached via connecting rings 6. On the other hand, as shown in FIG. 2, a substantially L-shaped connecting groove 6a is formed in the connecting ring 6 so as to extend downward from the upper end with a groove width into which the connecting pin 7 can enter and then bend substantially vertically. Therefore, with the holding portion 6b formed toward the inside of the connecting ring 6 holding the tapered surface 2a formed below the second plate 2, the connecting pin 7 is fitted into the connecting groove 6a, and the connecting ring 6 is inserted. This is fixed to the outer peripheral position of the first plate 1 by rotating, and the second plate 2 is attached to the first plate 1 with one touch.

The taper surface 2a of the second plate 2 and the connecting ring 6 thus mounted are slightly in a pressurized state during the polishing process so that the second plate 2 is not distorted. For example, a gap T of about 0.5 mm is formed so as to be in a non-contact state.

The second plate 2 for holding the semiconductor wafer (member to be polished) 8 is, as described above, the first plate 1.
Is provided opposite to. For example, a resin template 9 having a positioning hole 9a for positioning the semiconductor wafer 8 at a predetermined position is attached to one surface of the second plate 2 made of ceramic by an adhesive agent or the like. A holding pad 10 made of, for example, urethane foam is attached in the positioning hole 9a, and the semiconductor wafer 8 is held by the second plate 2 via the holding pad 10.

An annular load distribution ring (load distribution means) 11 is provided between the first plate 1 and the second plate 2. This load distribution ring 11 is arranged coaxially with the pressure rod 3, and as shown in FIG. 3, the load applied to the first plate 1 by the pressure rod 3 toward the base plate 5 is the load. It is dispersed by the dispersion ring 11 and transmitted to the second plate 2 (FIGS. 1 and 2).

Below the pressure plate 4, a base plate 5 on which the semiconductor wafer 8 held by the pressure plate 4 is pressed is located.

A polishing cloth 13 is attached to the front surface of the base plate 5 having a shaft 12 to which the rotational force of a motor (not shown) is transmitted in the central portion of the back surface.
The polishing agent 15 from the pipe 14 is dropped onto the polishing cloth 13. Then, the fine abrasive grains of the polishing agent 15 are generated by the rotational movements of the pressure plate 4 and the base plate 5, respectively.
The semiconductor wafer 8 is elasto-plastically held between and to polish the semiconductor wafer 8, and the semiconductor wafer 8 is mirror-finished.

In the polishing apparatus of this embodiment, the template 9
Of the second plate 2 holding the semiconductor wafer 8 on the holding pad 10 provided in the positioning hole 9a of the connecting ring 6 in the direction in which the taper surface 2a of the second plate 2 contacts the holding portion 6b.
Insert inside. Next, the second plate 2 is lifted, the connecting groove 6a of the connecting ring 6 is aligned with the connecting pin 7 attached to the outer peripheral surface of the first plate 1, and the connecting ring 6 is rotated to rotate the second plate. Plate 2 of 1st
Attach to plate 1 of. Then, the pressure plate 4 thus lowered is brought into pressure contact with the semiconductor wafer 8 against the base plate 5 by the pressure rod 3, and the pressure plate 4 and the base plate 5 are respectively rotated while dropping the polishing agent 15, whereby mirror polishing is performed. The semiconductor wafer 8 is obtained.

Here, as described above, the pressure plate 4 of the present polishing apparatus is provided with the first plate 1 to which the pressure rod 3 is attached, and the semiconductor wafer provided so as to face the first plate 1. Second plate 2 holding 8
And a load distribution ring 11 provided between the first plate 1 and the second plate 2. Therefore, the load applied to the vicinity of the center of the first plate 1 by the pressure rod 3 is dispersed by the load distribution ring 11 and transmitted to the second plate 2. Therefore, the load applied to the semiconductor wafer 8 held by the second plate 2 has a uniform distribution, and the semiconductor wafer 8 can be polished with high flatness.

Since the second plate 2 can be easily attached to the first plate 1 by the connecting ring 6, the work of attaching and detaching the semiconductor wafer 8 is quick and easy, and the workability is improved.

The tapered surface 2a of the second plate 2
The connecting ring 6 and the connecting ring 6 have a slight gap T during the polishing process.
Since the second plate 2 for holding the semiconductor wafer 8 is prevented from being distorted, the semiconductor wafer 8 polished to a high flatness can be stably manufactured.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, an annular load distribution ring 11 is used as the load distribution means in this embodiment, but a load distribution means such as a plurality of load distribution pins 21 as shown in FIG. 4 may be used. It is possible. In order to make the load distribution on the semiconductor wafer 8 uniform,
Although it is desirable to arrange them coaxially with the pressure rod 3 as in the present embodiment, in the case where the attachment strength of the pressure rod 3 to the first plate is sufficiently secured, it is non-coaxial. Any arrangement may be possible. The ring diameter of the load distribution ring 11 or the diameter of the load distribution pin 21 arranged in an annular shape can be set freely. Therefore, the load point can be adjusted to any position.

In the pressure plate 4 of the present embodiment, the connecting ring 6 is provided with the connecting groove 6a, which is fitted with the connecting pin 7 of the first plate 1.
Without using such connecting groove 6a and connecting pin 7,
It is also conceivable to screw the first plate 1 and the connecting ring 6 together.

The member to be polished such as the semiconductor wafer 8 may be adhered to the pressure plate 4 with wax, or may be adhered to the member to be polished with a film having good adhesion without using wax. it can.

Further, the semiconductor wafer 8 in this embodiment
Is only an example of the member to be polished, and in addition to the semiconductor wafer 8 including a silicon wafer and a compound semiconductor wafer, various members such as a magnetic disk and a liquid crystal glass that require mirror finishing are used as the member to be polished. Can be used.

[0037]

The effects obtained by the typical ones of the inventions disclosed in this application will be briefly described as follows.

(1) That is, according to the present invention, the pressure plate is provided to face the first plate to which the pressure rod is attached and the first plate to hold the member to be polished. Since the second plate and the load distribution ring provided between the first plate and the second plate are included, the load applied to the vicinity of the center of the first plate by the pressure rod is The load is dispersed by the load distribution ring and transmitted to the second plate. Therefore, the load applied to the member to be polished held by the second plate has a uniform distribution, and the member to be polished can be polished with high flatness.

(2) As a result, for example, when the member to be polished is a semiconductor wafer, polishing the semiconductor wafer to a high degree of flatness adversely affects the circuit pattern formation in the manufacturing process of the semiconductor device. Can be removed, and the yield of semiconductor wafers can be improved.

(3) Further, by arranging the load distribution ring and the plurality of load distribution pins coaxially with the pressure rod, it is possible to more surely make the load distribution of the member to be polished uniform. Become.

(4) Since the second plate can be easily attached to the first plate by using the connecting ring, the work for attaching and detaching the member to be polished is quick and easy, and the workability is improved. To do.

(5) By disposing the tapered surface of the second plate and the connecting ring in a non-contact state during the polishing process, the distortion of the second plate holding the member to be polished is prevented in advance. Therefore, it becomes possible to stably manufacture a member to be polished that has been polished to a high degree of flatness.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of a pressure plate by the polishing apparatus of FIG.

FIG. 3 is a perspective view showing a load distribution of a pressure plate by the polishing apparatus.

FIG. 4 is a perspective view showing a load distributing means according to another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional polishing apparatus.

[Explanation of symbols]

 1 1st plate 2 2nd plate 2a Tapered surface 3 Pressurizing rod 4 Pressure plate 5 Base plate 6 Connecting ring 6a Connecting groove 6b Holding part 7 Connecting pin 8 Semiconductor wafer (polished member) 9 Template 9a Positioning hole 10 Holding pad 11 load distribution ring (load distribution means) 12 shaft 13 polishing cloth 14 pipe 15 abrasive 21 load distribution pin (load distribution means) 33 pressure rod 34 pressure plate 35 base plate 38 semiconductor wafer 39 template 40 holding pad 43 polishing cloth 45 polishing Agent T gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Nishiyi 3-3 Fujibashi, Ome City, Tokyo 2 Hitachi Tokyo Electronics Co., Ltd.

Claims (8)

[Claims] 1. A first plate having a pressure rod attached to the center of one surface thereof; a second plate provided to face the first plate and holding a member to be polished; Is provided between the first plate and the second plate, and the load applied to the first plate by the pressure rod in the direction of the base plate is dispersed to disperse the second plate.
And a load distribution means for transmitting the pressure plate to the plate. 2. The pressure plate according to claim 1, wherein the load distribution means is an annular load distribution ring. 3. The pressure plate according to claim 1, wherein the load distribution means is a plurality of load distribution pins. 4. The pressure plate according to claim 2, wherein the load distribution ring or the load distribution pin is arranged coaxially with the pressure rod. 5. A taper surface is formed below the second plate, and the taper surface is held by a holding portion of a connecting ring fixed to an outer peripheral position of the first plate, whereby the second plate is formed. 5. The pressure plate according to claim 1, wherein the plate is attached to the first plate. 6. A connecting pin is attached to a plurality of locations on an outer peripheral surface of the first plate, and a connecting groove into which the connecting pin can be inserted is formed in the connecting ring in a substantially L-shape from an upper end to a lower part. The second plate is attached to the first plate by fitting the connecting pin into the connecting groove of the connecting ring holding the second plate and rotating the connecting ring. The pressure plate according to claim 5, wherein: 7. The pressure plate according to claim 5, wherein the tapered surface and the connecting ring are in a non-contact state with a slight gap formed in a pressure state by the pressure rod. . 8. A polishing apparatus comprising the pressure plate according to any one of claims 1 to 7.