JPH10113863A - Polishing guide device positioning method and device, and thin plate substrate polishing method - Google Patents

Abstract

(57) [Summary] [Purpose] Eliminate polishing droop on the polished surface of a thin plate substrate,
An object of the present invention is to provide a method for positioning a polishing guide device capable of polishing a polished surface with good in-plane uniformity and a device therefor. A positioning device for a polishing guide device according to the present invention is provided.
Before the polishing of the thin plate-shaped substrate S held by the rotating substrate holding device 10 in which the guide device 14 is mounted on the peripheral portion of the substrate holding plate 12 and the backing pad 13 is attached to the flat surface of the substrate holding side, The thin plate-shaped substrate is brought into contact with the flat surface 31A of the surface plate 31, a predetermined polishing pressure is applied, the backing pad 13 is compressed, and the lower surface of the guide device is maintained while maintaining the height close to the actual polishing state. Is brought into contact with the flat surface so that the surface to be polished of the thin plate-shaped substrate is adjusted to the same plane, and the guide device is positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor wafer, L
Positioning method and apparatus for a polishing guide device capable of polishing a surface to be polished of a thin plate-like substrate such as a glass plate for a CD with a large polished area as close to an ideal surface as possible with good in-plane uniformity, and the thin plate The present invention relates to a method for polishing a substrate.

[0002]

2. Description of the Related Art First, a conventional apparatus for polishing a thin substrate and a polishing method using the apparatus will be described with reference to FIGS. FIG. 3 is a cross-sectional view showing a part of a conventional apparatus for polishing a thin plate substrate in a polishing state, and FIG. 4 is a view of the polishing apparatus shown in FIG. 3 for holding the thin substrate to be polished. It is sectional drawing which showed the rotary substrate holding device of the prior art in the state before a grinding | polishing operation | movement.

In the case of polishing a thin substrate, for example, a semiconductor wafer (hereinafter, a "semiconductor wafer" will be described as an example of a thin substrate to be polished), a polishing apparatus 100 having the structure shown in FIG. It is performed using. The polishing apparatus 100 is roughly composed of a polishing platen 110, a substrate holding device 120, and a nozzle 130.

The polishing platen 110 has, for example, a flat surface having an area having a diameter twice or more the diameter of the semiconductor wafer S, and a polishing pad 111 made of, for example, a nonwoven fabric made of a polyester resin is adhered to the flat surface. It is adhered with an agent or the like, and is configured to rotate around the rotation shaft 112 at, for example, 30 rpm in the direction of the arrow Ra.

[0005] The substrate holding device 120 is provided with the polishing platen 1.
10 and the rotation axis 1 of the polishing platen 110
12, for example, the center of the radius of the polishing platen 110 has a center of rotation, and the upper and lower variable shafts 121B and 121 have the center of rotation adjusted above and below the universal joint 121A.
For example, it rotates around the rotation shaft 121 made of C at the same number of rotations as the polishing platen 110, 30 rpm, and in the same rotation direction (arrow Rb).

[0006] As shown in FIG. 4, the substrate holding device 120 has a substrate holding plate 122 having a central portion, and a substrate holding member for holding the semiconductor wafer S on the lower surface of the substrate holding plate 122. A backing pad 123 which is one form is fixed. Further, an epoxy resin guide ring 124 having an inner diameter slightly larger than the outer diameter of the semiconductor wafer S for preventing the semiconductor wafer S from jumping out is fixed to the outer peripheral surface of the backing pad 123. For the backing pad 123, a polyurethane or polyester resin sheet having a thickness of about 1.5 mm is used. Further, the nozzle 130 is a polishing liquid supply device, and supplies the polishing liquid L between the polishing pad 111 and the semiconductor wafer S near the rotation center of the polishing platen 110.
FIG. 3 shows only the right half of the polishing platen 110 for convenience.

In polishing the semiconductor wafer S,
As shown in FIG. 4, the semiconductor wafer S to be polished is
The surface to be polished Sa is set to the outside, that is, the lower side, and the backing pad 123 is held by water absorption, and as shown in FIG. 121, a pressure (arrow P) is applied to the surface of the polishing pad 111 of the polishing table 110 with a predetermined pressing force via the universal joint 121A, and the polishing table 110 is rotated at the rotation speed by the arrow Ra.
While supplying the polishing liquid L from the nozzle 130 to the surface of the polishing pad 111, and while rotating the substrate holding plate 122 holding the semiconductor wafer S in the direction of the arrow Rb at the rotation speed, The surface to be polished Sa of the semiconductor wafer S is chemically and mechanically polished (hereinafter simply referred to as “polishing”) with the polishing pad 111 and the polishing liquid L. During polishing, the semiconductor wafer S is held in the substrate holding device 120.
In addition, the semiconductor wafer S tends to jump out of the polished surface due to the rotation of the polishing platen 110, but the guide ring 124 can prevent the semiconductor wafer S from jumping out during polishing.

[0008]

In the prior art method of polishing a semiconductor wafer, when polishing the semiconductor wafer S, the semiconductor wafer S is usually polished in a state of protruding from the lower surface of the guide ring 124. . This protrusion amount is shown in “Semiconductor wafer protrusion amount and in-plane uniformity” shown in FIG.
As shown in the relationship graph of FIG.
It is about 00 μm. The reason why the protrusion amount is determined to such a value is that the protrusion amount is increased in order to make the polishing liquid L penetrate well between the polishing surface Sa of the semiconductor wafer S and the polishing pad 111. It is better, but it is better to reduce the size in order to prevent the semiconductor wafer S from shifting. Therefore, the size is determined in consideration of the balance.

However, when the polished surface Sa of the semiconductor wafer S is polished under such conditions, the polished surface Sa has an in-plane uniformity of ± 10%, as is clear from the graph of FIG. The variation was as large as about 20%, which was not very good. The main cause of the poor in-plane uniformity of the polished surface Sa is that the lower surface 124A of the guide ring 124 is receded with respect to the polished surface Sa.
It is considered that this is because the polishing pad 111 sinks into the polishing pad 111 and the pressing force of the polishing pad 111 is applied more strongly to the peripheral portion than to the central portion of the semiconductor wafer S, so that the polishing rate of the outer peripheral portion is increased. It is considered that so-called polishing drooping occurs, and this polishing dripping impairs the in-plane uniformity of the polished surface.

In order to eliminate the sagging, the optimum protrusion amount of the semiconductor wafer S projected downward from the lower surface of the guide ring 124 at the time of polishing, as shown in the "invention" portion of the graph of FIG. When it is set in the range of 0 to 5 μm, the in-plane uniformity of the surface to be polished becomes the best. However, since this also includes the amount of compression of the backing pad, it has been found that the same pressure, which is almost the same plane, is best in the actual polishing state.

In the present invention, before the actual polishing, the semiconductor wafer held by the substrate holding device and the guide device are adjusted in advance so as to be substantially on the same plane, and then the actual polishing is performed. Eliminate polishing drool as described above,
It is an object of the present invention to obtain a method for positioning a polishing guide device capable of polishing a surface to be polished with good in-plane uniformity, a device therefor, and a method for polishing a thin plate-like substrate.

[0012]

Therefore, in the method of positioning a polishing guide device according to the present invention, a guide device is mounted on a peripheral portion of a substrate holding board, and a substrate holder is mounted on a flat surface of the substrate holding side. In polishing the surface to be polished of the thin plate-like substrate held on the substrate holding plate of the rotating substrate holding device via the substrate holding body by a polishing pad mounted on the surface of the rotary polishing platen, the surface is flat to a predetermined level. The flat surface of the flat surface plate that has been finished is brought into contact with the polished surface of the thin plate-shaped substrate held by the rotating substrate holding device and the guide device without rotating the flat surface, and in this contact state, A predetermined polishing pressure is applied to the thin plate-like substrate, and the lower surface of the guide device is brought into contact with the flat surface so that the surface to be polished of the thin plate-like substrate is adjusted to be substantially coplanar to position the guide device. Take the method, It has solved the serial problems.

Further, the positioning device of the polishing guide device of the present invention as one means capable of executing the positioning method of the guide device comprises a substrate holding device and a height position adjusting device of the guide device. A substrate holding device is provided on a supporting substrate, a substrate holding plate fixed to the lower surface central portion of the supporting substrate, and an outer peripheral portion of the substrate holding plate, and is movable vertically from the peripheral portion of the supporting substrate. , A driving device for moving the guide device in the vertical direction, and a pressing device for applying a predetermined polishing pressure from behind the substrate holding plate, and The height position adjusting device has a flat surface plate whose surface is finished to a predetermined flat surface, and the thin plate substrate and the guide device supported by the substrate holding device on the flat surface of the flat surface plate. A plurality of displacement sensors disposed on a flat surface plate at a position where the guide device is mounted, and the driving device is controlled based on a height position signal detected by the displacement sensors. And a control device for generating a control signal.

Further, the method for polishing a thin plate-like substrate according to the present invention comprises:
Using the positioning method of the guide device, the guide device is mounted on a peripheral portion of the substrate holding plate, and the substrate holding member is mounted on the substrate holding plate of the rotating substrate holding device in which the substrate holding member is mounted on the substrate holding side plane. In polishing the polished surface of the thin plate-shaped substrate held via the polishing pad mounted on the surface of the rotary polishing platen, the flat surface of the flat surface plate is finished to a predetermined flat surface. The polished surface of the thin plate-shaped substrate held by the rotating substrate holding device is brought into contact without rotating, and in this contact state, first, a predetermined polishing pressure is applied to the thin plate-shaped substrate, and the lower surface of the guide device is Is brought into contact with the flat surface to adjust the surface to be polished of the thin plate-like substrate to a substantially coplanar state, and then the adjusted rotary substrate holding device is moved to the polishing surface of the rotary polishing platen, and the substantially The thin plates in the same plane It adopts a polishing method for polishing the surface of the Jo substrate to solve the above problems.

Therefore, according to the present invention, the height position of the lower surface of the guide device can be easily adjusted to the polished surface of the thin substrate by pressing the lower surface of the guide device to the polished state. Since the surfaces can be apparently enlarged on the lower surface of the guide device, when both surfaces are simultaneously polished with the polishing platen, it is possible to prevent the deterioration of the polishing uniformity due to the surface drooping, and to maintain the in-plane in a preferable state. Polishing can be performed with good uniformity.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a positioning apparatus for a polishing guide device and a method for polishing a thin plate-like substrate according to the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing an embodiment of a positioning device for a polishing guide device according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.

First, the configuration of the positioning device of the polishing guide device of the present invention will be described. In FIG. 1, reference numeral 1 indicates a positioning device (hereinafter simply abbreviated as “positioning device”) of the polishing guide device of the present invention. This positioning device 1
Is roughly composed of a substrate holding device 10 and a height position adjusting device (hereinafter simply referred to as “height position adjusting device”) 30 of the guide device.

The substrate holding device 10 is formed around a disk-shaped support substrate 11, and a disk-shaped substrate holding plate 12 is fixed to the center of the lower surface of the support substrate 11. A backing pad 13, which is one form of a substrate holder, is attached to the substrate. Also, the board holding board 1
A ring-shaped polishing guide device (hereinafter simply abbreviated as “guide device”) 14 is disposed on the outer peripheral surfaces of the backing pad 2 and the backing pad 13 independently of the substrate holding board 12. The guide device 14 has an inner diameter slightly larger than the outer diameters of the semiconductor wafer S and the substrate holding board 12, and is made of epoxy resin. In addition, as the substrate holder, there is a vacuum chuck formed of a porous material or the like in addition to the pad type, and this vacuum chuck may be used.

On the other hand, three to twelve motors 15 are fixed to the peripheral portion of the upper surface of the support substrate 11. As shown in FIG. 2, eccentric cams 16 are attached to the shafts of these motors 15. The pressing rod 17 reaching the upper surface is arranged in a structure capable of moving up and down. A pressing plate 1 is provided at the upper and lower ends of each pressing rod 17.
8 and 19 are formed. It is desirable that the width of the lower pressing plate 19 be equal to the width of the guide device 14. The upper pressing plate 18 is always pressed against the eccentric cam 16. This pressure contact is performed by the repulsive force of the coil spring 20 attached and mounted on the lower surface of the pressing plate 18 and the pressing rod 17 existing on the upper surface of the support substrate 11. Motor 15
A pair of terminals 22 is led out at the upper part of the terminal.

Further, a rotating shaft 21 is fixed to the center of the upper surface of the support substrate 11. The rotating shaft 21 is constituted by upper and lower variable shafts 21B and 21C whose rotation centers are adjusted up and down through a universal joint 21A. The substrate holding device 10 rotates about the rotation shaft 21 when polishing a thin plate-like substrate held on the substrate holding board.

The height position adjusting device 30 is mainly composed of a flat surface plate 31 whose surface is finished to a predetermined flat surface 31A. The flat surface plate 31 is formed of ceramic, glass, or the like. At the center of the flat surface plate 31, when a thin plate-like substrate, for example, the semiconductor wafer S and the guide device 14 supported by the substrate holding plate 12 on the flat surface 31A are mounted, the semiconductor wafer S is mounted. A through hole 32 is formed at the center of the lower surface at the position where the guide device 14 is placed, and the peripheral surface of the flat surface plate 31 is equiangularly spaced from the lower surface at the position where the guide device 14 is placed. plural,
For example, four through holes 32 are formed. A contact-type displacement sensor (hereinafter simply abbreviated as “displacement sensor”) 33A for the semiconductor wafer S is provided in the central through-hole 32.
However, a contact type displacement sensor 33B is provided in each through hole 32 in the peripheral portion.
Is inserted and mounted. These displacement sensors 33A,
33B is adjusted and fixed in advance to a zero position on the flat surface of the flat surface plate 31.

The output terminals of one displacement sensor 33A and four displacement sensors 33B are connected to the motor control device 3 by a cable 34.
5 input terminals and four displacement sensors 3
The output terminal corresponding to 3B is connected to the terminal 22 of each motor 15 via a cable 36 and a quick contact 37 connected to their distal ends. The motor control device 35 includes a guide device 1 that is input via one cable from one displacement sensor 33A and four displacement sensors 33B.
The height signal of 4, the cable 36, the quick contact 3
7. By rotating the motor 15 through the terminal 22 of the motor 15 and finely rotating the eccentric cam 16, the guide device 14
The motor 15 is provided with a control function to stop the motor 15 when the height becomes zero. Reference numeral 38 indicates a power cable.

Next, the positioning device 1 having the configuration described above.
Will be described. Before polishing, the cable 36
A pair of quick contacts 37 at the tip of
The terminal 15 is connected to the terminal 22 by one-touch so that the motor 15 can rotate. Then, a thin plate substrate to be used for polishing, for example, a semiconductor wafer S is held on the surface of the backing pad 13 of the substrate holding device 10 by water absorption, and the entire substrate holding device 10 is measured on the flat surface 31A of the flat surface plate 31 at the measurement position. Then, the substrate holding device 10 is lowered without rotating, and is placed on the flat surface 31A. Next, a polishing pressure P is applied to the rotating shaft 21 and a pressure corresponding to the polishing pressure P is applied to the semiconductor wafer S. When the pressure is applied, the backing pad 13 is compressed, and the height of the semiconductor wafer S which is almost in a polished state can be simulated.

The motor 15 is rotated forward and backward by the motor control device 35, and the eccentric cam 16 is rotated forward and backward. The pushing rod 17 is raised or lowered to move the guide device 14 up and down. When the displacement sensors 33B detect the zero position of the guide device 14 while being in contact with the device 14, the motor 15 is stopped by the height position control signal supplied from the motor control device 35. In this way, when each motor 15 is at the zero position, the height position between the polished surface of the semiconductor wafer S and the lower surface of the guide device 16 is adjusted to the same height, and the adjustment is completed.

When the detection output of the displacement sensor 33A−the detection output of the displacement sensor 33B = (−), the guide device 16
Is retracted above the surface to be polished of the semiconductor wafer S, and the detection output of the displacement sensor 33A-the displacement sensor 33
When the detection output of B = (+), the lower surface of the guide device 16 is closer to the flat surface 31A of the flat surface plate 31 than the polished surface of the semiconductor wafer S. The eccentric amount of the eccentric cam 16 is 180 °
The rotation is preferably 100 to 500 μm. In the case of 100 μm, a change of 10 μm can be obtained by the rotation of 18 °.

Following the above procedure, the semiconductor wafer S
Holding device 1 in which the height between guide and guide device 14 is adjusted
0 is then moved to the polishing section. A polishing table 110 shown in FIG. 4 is installed in the polishing section.
For example, the polishing platen 11 which is displaced from the rotation shaft 112 of
The substrate holding device 10 is positioned so that the rotation axis 21 is located at the center of the radius of 0, and then lowered, the nozzle 130
While the polishing liquid L is supplied to the polishing surface from the substrate holding device 1
0 with the rotation axis 21 as the center, for example, the polishing platen 1
The semiconductor wafer S is rotated at the same rotational direction (arrow Rb) at 30 rpm as the number of rotations of 10, and the surface to be polished of the semiconductor wafer S is subjected to chemical mechanical polishing (polishing) with the polishing pad 111 and the polishing liquid L.

When the polishing is performed by such a polishing method, the surface to be polished of the semiconductor wafer has an apparently enlarged diameter by the guide device 14, so that the surface of the semiconductor wafer S which tends to be formed at the peripheral portion is eliminated. In addition, it is possible to prevent the in-plane uniformity of the polished surface of the semiconductor wafer S from deteriorating.
During the polishing, the semiconductor wafer S tends to jump out of the polishing surface by the rotation of the substrate holding device 10 and the polishing platen 110. However, the presence of the guide device 14 can prevent the semiconductor wafer S from jumping out during polishing. As a result, the guide device 14 according to the present invention also performs its original function.

The positioning device 1 of the present invention shown in FIG.
Since the displacement sensor 33A is disposed at the center of the flat surface plate 31 to detect the height position of the surface to be polished of the semiconductor wafer S, the semiconductor wafer supported by the support substrate 11 and the substrate holding plate 12 Regardless of whether the height position of the lower surface of the guide device 16 supported by the support substrate 11 with respect to the height position of the polished surface of S is in the upper position or the lower position,
The lower surface of the guide device 16 can be aligned at the same height position as the surface to be polished of the semiconductor wafer S. However, when the support device 11 supports the guide device 16, the lower surface of the guide device 16 is By retreating above the polishing surface in advance, the displacement sensor 33A disposed at the center of the flat surface plate 31 can be omitted.

That is, when the semiconductor wafer S and the guide device 16 having the above-described height positional relationship are set on the flat surface plate 31, first, the polished surface of the semiconductor wafer S comes into contact with the flat surface 31A of the flat surface plate 31. , The polishing pressure P on the semiconductor wafer S
, The motor 15 is driven under the control of the motor control device 35, the eccentric cam 16 is rotated, the guide device 16 is lowered, and is brought into contact with the flat surface 31A of the flat surface plate 31. Thus, the lower surface of the guide device 16 can be aligned at the same height position as the surface to be polished of the semiconductor wafer S.

[0030]

As is clear from the above description, the following excellent effects can be obtained by using the method and the apparatus for positioning a polishing guide device of the present invention and the method for polishing a thin plate substrate. That is, 1. 1. The in-plane uniformity of the thin substrate is improved by polishing the surface to be polished. 2. With the polishing pressure applied, the polished surface of the thin plate-shaped substrate and the backing pad surface can be made flush with each other. 3. Positioning of the guide device can be automated by interlocking the displacement sensor and the motor. 4. Because the flat surface plate is made of non-metal, it is not affected by metal contamination or dust. The position of the guide device is stable during polishing because it is pressed against the eccentric cam by a spring.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a positioning device for a polishing guide device of the present invention.

FIG. 2 is a cross-sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view showing a part of a conventional apparatus for polishing a thin plate substrate in a polishing state.

FIG. 4 is a cross-sectional view showing a conventional rotating substrate holding device of the polishing device shown in FIG. 3 in a state before a polishing operation for holding a thin substrate to be polished;

FIG. 5 is a graph showing a relationship between a protrusion amount of a semiconductor wafer and in-plane uniformity of a polished surface.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positioning device of this invention, 10 ... Substrate holding device, 11
... Support substrate, 12 ... Substrate holding board, 13 ... Backing pad, 14 ... Guide device, 15 ... Motor, 16 ... Eccentric cam, 17 ... Pressing rod, 18, 19 ... Pressing plate, 20 ... Coil spring, 21 ... Rotating shaft , 30 ... height position adjusting device, 31 ...
Flat surface plate, 31A: Flat surface, 32: Through hole, 33A, 3
3B (contact type) displacement sensor, 35 ... motor control device,
L: polishing liquid, S: semiconductor wafer (thin plate-shaped substrate)

Claims (5)

[Claims] A guide device is mounted on a peripheral portion of a substrate holding plate, and a substrate holding member is mounted on a substrate holding side flat surface of the rotating substrate holding device. In polishing the polished surface of the thin plate-shaped substrate by the polishing pad mounted on the surface of the rotary polishing platen, the rotating substrate is held on the flat surface of the flat surface plate whose surface is finished to a predetermined flat surface. The polished surface of the thin plate-shaped substrate held by the device is brought into contact with the guide device without rotating, and in this contact state, a predetermined polishing pressure is applied to the thin plate-shaped substrate, and the lower surface of the guide device Abutting the flat surface to adjust the surface of the thin substrate to be polished to be substantially flush with the surface to be polished, and positioning the guide device. 2. A guide device is mounted on a peripheral portion of a substrate holding board, and a substrate holding body is mounted on a substrate holding side flat surface of the rotating substrate holding apparatus. In polishing the polished surface of the thin plate-shaped substrate by the polishing pad mounted on the surface of the rotary polishing platen, the rotating substrate is held on the flat surface of the flat surface plate whose surface is finished to a predetermined flat surface. The surface to be polished of the thin plate substrate held by the device is brought into contact without rotating, and in this contact state, first, a predetermined polishing pressure is applied to the thin plate substrate, and then the lower surface of the guide device is A method for positioning a guide device for polishing, wherein the guide device is positioned by abutting the flat surface to adjust the surface to be polished of the thin plate-like substrate to be substantially flush with the surface. 3. A supporting substrate, a substrate holding plate fixed to a central portion of a lower surface of the supporting substrate, and arranged on an outer peripheral portion of the substrate holding mounting plate, and vertically moving from the peripheral portion of the supporting substrate. A substrate holding device, comprising: a guide device that is supported so as to be movable; a driving device that moves the guide device in the vertical direction; and a pressing device that applies a predetermined polishing pressure from behind the substrate holding plate. 4. A supporting substrate, a substrate holding plate fixed to a central portion of a lower surface of the supporting substrate, and arranged on an outer peripheral portion of the substrate holding plate, and movable vertically from a peripheral portion of the supporting substrate. A driving device for moving the guide device in the vertical direction; and a pressing device for applying a predetermined polishing pressure from behind the substrate holding plate. A flat surface plate finished to a predetermined flat surface; and a thin plate-like substrate and a guide device supported by the substrate holding device mounted on the flat surface of the flat surface plate. A plurality of displacement sensors arranged on the flat surface plate at the position determined, a control device for generating a control signal for controlling the driving device based on the height position signal detected by these displacement sensors,
A positioning device for a polishing guide device comprising: 5. A rotary board holding device having a guide device mounted on a peripheral portion of a substrate holding plate and a substrate holding member mounted on a substrate holding side flat surface of the substrate holding plate via the substrate holding member. In polishing the polished surface of the thin plate-shaped substrate by the polishing pad mounted on the surface of the rotary polishing platen, the rotating substrate is held on the flat surface of the flat surface plate whose surface is finished to a predetermined flat surface. The surface to be polished of the thin plate-shaped substrate held by the device is brought into contact without rotating, and in this contact state, first, a predetermined polishing pressure is applied to the thin plate-shaped substrate, and the lower surface of the guide device is moved to the flat surface. After adjusting the surface to be polished of the thin plate-like substrate to be substantially flush with the polishing surface of the thin plate-shaped substrate, the adjusted rotating substrate holding device is moved to the polishing surface of the rotary polishing platen, and is brought into the substantially flush state. Polish the surface to be polished of the thin plate-shaped substrate A method for polishing a thin plate-shaped substrate.