JPS6331342B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polishing materials to be polished such as semiconductor wafers and metal pieces, and more specifically to a method for uniformly applying pressure to the material to be polished and fixing the material to the center hole of the surface plate. The material to be polished is rotated by giving a rotating locus that partially overhangs the material fixed to the part and partially overhangs outward from the outer periphery, thereby preventing the occurrence of comet tails that conventionally occur during polishing. It is an object of the present invention to provide a polishing method that eliminates non-uniformity depending on the location of the edge portion, that is, edge sagging, and also allows the polishing machine to be downsized.

Conventionally, polishing of materials to be polished such as semiconductor wafers and metal pieces has been carried out by attaching several materials to be polished in the circumferential direction of the lower surface of a dish-shaped or revolver-shaped fixed part, and pressing the center of the fixed part with a rotating shaft. Polishing was performed at an appropriate rotation direction and rotation speed at a radial portion radially outward from the center of the plate, but in this polishing method, the amount of wear of the abrasive material on the surface plate was determined by the rotation of the material to be polished radially outward. Because the thickness of the abrasive material differs significantly between the inside of the trajectory and the edge of the trajectory at the center of the surface plate, the thickness of the abrasive material becomes uneven, causing inclination of the polished surface of the material to be polished and edge sag on the periphery. In a polishing method in which the material to be polished is arranged around a fixed part and the central part is pressed by a rotating shaft, even if the rotating shaft and the fixed part of the material to be polished are completely fixed, cantilever support Because polishing was performed under eccentric pressure, which occurs in principle, uneven wear phenomenon occurred on the polishing surface of the material to be polished, and in order to correct this and obtain the desired polishing state, long-term polishing was required. In addition, since polishing debris from the material to be polished and abrasive debris from the abrasive material are always present between the material to be polished and the polishing material without being removed, especially in the center, scratches or scratches on the polishing surface. Comettail was occurring.

In view of these conventional problems, the present invention was completed as a result of intensive research to solve the problems.The purpose of the present invention is to be able to polish the material to be polished in a short time, and to create comet tails on the polished surface. It is an object of the present invention to provide a polishing method that does not cause edge sag on the edges or the periphery thereof and can further downsize the polishing machine.

That is, in the present invention, an abrasive material having approximately the same shape in plan view is placed on a surface plate having a circular hole in the center, and a material to be polished is mounted on an eccentric rotation fixing part facing the surface of the surface plate, and this is fixed. When applying pressure to the surface of the surface plate while eccentrically rotating it with a drive device separate from the disk drive device, and rotating the surface plate to polish the material to be polished,
An elastic intervening body having a pressure adjustment part is interposed between the eccentric rotating pressurizing part and the part to be polished to uniformly distribute the eccentric pressing force of the rotating pressurizing shaft of the part to be polished to the part to be polished to the part to be polished. , furthermore, on the surface plate, the workpiece fixed to the workpiece fixing part partially overhangs the center hole of the surface plate, and also partially protrudes outward from the outer periphery of the surface plate. The gist thereof is a polishing method characterized by polishing a material to be polished by applying a locus.

The details of the present invention will be explained based on the embodiments shown in the drawings. Fig. 1 is a sectional view of an example of a polishing apparatus developed to carry out the polishing method of the present invention, and Figs. 7 is a plan view and a side view of an embodiment of an elastic intervening body for evenly distributing the eccentric pressurizing force of the rotating pressurizing shaft, and FIG. 7 is an explanatory plan view showing the rotation locus of the material to be polished on the surface plate.

That is, the polishing apparatus according to the embodiment shown in FIG. 1 includes a rotating pressurizing device A for rotating the material to be polished and a surface plate rotating device B as shown. Polished material rotating pressurizing device A
, a polishing material fixing part 1, a rotary pressure shaft 2 connected thereto, and a drive device 3 for rotating and pressurizing these.
It becomes more.

Here, in the embodiment in which the workpiece to be polished 1 is mounted on a single piece, as shown in the figure, the attachment hole 6 is formed in the center of the ring-shaped upright part 7 so that a synthetic resin sample fixing member 5 having the workpiece to be polished 4 therein can be attached thereto. To the annular upright portion 7 of the base body 8 formed in the above, the pressing force on the rotary press shaft 2 side is weaker and the side spaced apart from the shaft 2 as shown in FIGS. 2, 3, and 4 is applied. An elastic intervening body 10 having a pressure adjusting section 9 for increasing the pressure applied thereto is fitted.
In addition, in the case of applying a large number of polishing materials, a dish top or a revolver-shaped fixing portion on which three or more materials to be polished 4 are attached is used as in the conventional case. The elastic intermediary body 10 is made of rubber or soft synthetic resin, and is used to uniformly disperse eccentric pressurizing force from a rotating pressurizing shaft 2 (described later) to the polishing surface of the material to be polished 4, thereby improving the polishing effect. used for the second
What is shown in the figure is such that the mounting hole 11 of the elastic intervening body 10 is slightly displaced in the direction of the rotating pressurizing shaft 2, and the width a of the elastic intervening body 10 on the eccentric pressurizing side, that is, on the rotating pressurizing shaft 2 side.
is smaller than the width b on the opposite coaxial side, for example, a:b=1:3, and in the case of the one in FIG.
In the one shown in FIG. 4, the pressure adjustment portion 9 is formed so that the difference c between the thickness at the end in the direction of the center of eccentric pressure and the thickness on the opposite side is approximately 1/100 of the diameter d.

These elastic intervening bodies 10 deflect the pressure adjustment part 9 toward the center of the axis in the eccentric pressurizing direction or to one side (for example, the elastic intervening bodies 10 in FIG. A fitting hole 1 is attached to a rotating pressurizing shaft 2 which can be fitted into the pressurizing adjustment part 9 of the base body 8 with the displacement (deviation) and also fit into the annular upright part 7 thereon.
2 is placed on top. Furthermore, the fifth
The one shown in FIG. 6 is another embodiment of the elastic interposer 10, which is used for simply mounting.

The rotary pressure shaft 2 is fixed to one side of the compression part 13,
The compression part 13 is eccentrically positioned so that pressing force and rotational force can be transmitted from above the shaft 2.
The rotational force and pressurizing force of the rotary pressurizing shaft 2 are applied by a pressurizing section 15 and a driving section 16 provided on the upper support frame 14 of the polishing machine body.

The pressurizing part 15 can move up and down, but its rotation is restricted by a pin 19 that is provided by drilling a long groove 18 on one side of the cylindrical housing part 17 provided inside the upper support frame 14 and penetrating it from the outside of the housing part. A spindle sleeve 22 is installed inside the slide core 20 via a bearing 21, and a rotary pressure shaft 2 is installed at the bottom of the spindle sleeve 22. A pressure support rod 23 is provided upright within the spindle sleeve 22 and projects above the upper support frame 14. The rotary pressure shaft 2 is
A vertical groove 24 is formed on the side of the shaft 2 so that the spindle moves up and down in the sleeve 22, but its free movement is restricted.A vertical groove 24 is formed on the side of the shaft 2, and the shaft 2 rotates with the sleeve 22 using a pin 25. A spring 26 is fixed to the upper part of the spindle sleeve 22 to apply pressure. A spring stopper 27 is fixed to the upper part of the sleeve, and a spring stopper 28 is fixed to the upper end of the rotating pressurizing shaft 2 while floating upward in the sleeve.
A rotary pressure shaft 2 inserted between the shafts and movable up and down is always urged downward.

In order to move the slide core 20 downward by fitting it onto the pressure indicator rod 23, the core slide screw portion of the shaft 30, which is placed or fixed on the slide core 20 and stands up at the same time, is placed on the support frame 14. This is a core descending portion that is screwed together with a handle wheel 31 provided on the handle wheel 31.

By rotating the handle 32, the core lowering part 29 is lowered, and when the slide core 20, bearings 21, 21, and spindle sleeve 22 are lowered by this, the upper spring stopper 27 is also displaced downward. At this time, if the lower end position of the rotating pressurizing shaft 2 is constant, the spring 26 is compressed by the spring stopper 27 and transmits the pressurizing force to the rotating pressurizing shaft 2. Therefore,
This pressing force is applied to the upper spring stopper 27.
Since it changes depending on the set position, it can be adjusted by rotating the handle 32. At this time, the pressure indicator rod 2 protruding above the handle wheel 31
By marking the scale at 3, you can see how much pressure is being applied to the rotary pressure shaft 2.

The drive unit 16 is composed of a motor 35 with a transmission connected to a gear 33 fitted on the spindle sleeve 22 via a gear 34, and by rotating the motor 35 in forward and reverse directions, the gear is connected to a gear 33 fitted on the spindle sleeve 22 through the gear 34. 33, and the rotating pressurizing shaft 2 is located at the center of rotation and is freely movable up and down and is biased downward.
is rotated, and the material to be polished 4 and the material to be polished 5 are rotated about the rotating pressurizing shaft 2 under eccentric pressure. Therefore, since the distance between the center of the rotary pressure shaft 2 and the center of the material to be polished 4 is approximately the radius of rotation, that is, the radius of the polishing locus, as will be described later, it partially overhangs the center hole of the surface plate, and
When taking a rotation locus that partially protrudes outward from the surface plate's outer periphery and overhangs, the length of the rotation radius must be determined in accordance with the surface plate diameter.

Note that a switching device 36 such as a timer is attached so that the rotating direction of the rotary pressure shaft 2 and/or the surface plate (to be described later) can be reversed forward or reverse for a certain period of time or at a certain number of rotations.

Next, the surface plate rotating device B will be explained. It polishes the workpiece 4 fixed to the workpiece fixing part 1 to which rotational force and downward pressing force are applied by the rotary pressure shaft 2. A polishing surface plate 37 having a center hole 42 so that the lower surface of the fixed part 1 can be bonded and polished.
is pivoted in a water-sealed state into a housing portion 38 provided at the center of the body, and the pivot is rotatable by a drive portion 40. 41 is a drain pipe provided to the bottom plate of the housing portion 38.

The configuration of the illustrated embodiment of the polishing machine according to the present invention is as described above, so in order to perform polishing using this, for example, a metal piece as the material to be polished 4 must be synthesized with one side exposed. The sample formed by embedding it in the resin fixing material 5 is inserted into the mounting hole 6 in the center of the base 8.
This is mounted on a surface plate 37 with an abrasive material arranged on the upper surface, and the pressing part 13 of the rotary pressurizing shaft 2 that has been lowered by rotating the handle 32 in the downward direction from above is pressed against it. It is fitted onto the annular upright portion 7 of the material-to-be-polished fixing portion 1 through the fitting hole 12, and is pressed and set on the surface plate 37 with the required pressure. At this time, a pressure adjustment part 9 is attached to the annular upright part 7 of the polishing material fixing part 1 in order to disperse the eccentric pressing force caused by eccentrically fixing the compression part 13 to the lower end of the rotary pressure shaft 2. By fitting the elastic intervening body 10 positioned in the radial direction around the pressing shaft 2 and interposing it between the pressing part 13 and the base body 8, the rotating pressing shaft 2 and the pressing part 13 are
This occurs because the downward eccentric pressing force applied through the shaft is distributed over the entire surface of the material to be polished 4, that is, the pressing force applied near the rotary pressing shaft 2 is stronger than the pressing force on the side remote from the shaft. The eccentric pressurizing force is adjusted by a pressurizing adjustment section 9.

Further, when polishing three or more pieces at the same time, the fixed part 1 is eccentrically pressurized by using the elastic intervening body 10 shown in FIGS. 5 and 6 or by directly rotating the pressurizing shaft 2 as in the conventional case.

In this way, the polishing material fixing part 1 pressed against the surface plate surface with a constant pressure is placed on the surface plate 37 by the motor 3.
At step 5, rotate the rotary pressure shaft 2 and rotate the surface plate 3.
7 is rotated in a fixed direction by the drive unit 40 and polished in the usual manner. At this time, the rotary pressure shaft 2 and the material to be polished 4
As mentioned above, the distance between the center positions of the material to be polished 4
The rotation locus is set so that it partially overhangs the center of the surface plate 37 and also partially protrudes from the outer peripheral edge of the surface plate 37.

That is, the diagram shown in FIG. 7 explains the rotation locus of the material to be polished 4 on the surface plate 37, and when the material to be polished 4 is rotated around the rotary press shaft 2, The center position of the material to be polished 4 overhangs the center hole 42 of the surface plate 37, and the material to be polished 4 has a rotation trajectory 43 in which a part of the material to be polished 4 overhangs outward from the outer peripheral edge of the surface plate 37. The polishing direction is alternately performed by rotating the material to be polished and then reversing the rotation of the rotary pressure shaft 2 and/or the surface plate 37 in the forward and reverse directions for a certain period of time or at a certain number of rotations. It is.

Next, examples of the present invention will be shown below.

The downward pressing force of the rotary pressing shaft 2 in the rotary pressing device A for the polished material is 400 g/cm ² , its rotation speed is 10 rpm, the rotation speed of the surface plate 37 is 400 rpm, and the outer diameter of the surface plate 37 is 130 mmφ (center hole). 10mmφ), paper grain size #120, and 25mmφ carbon iron (270HV)
is resin-molded to a diameter of 32 mm, and the a:b ratio of the elastic intervening body 10 shown in Fig. 2 is (1) a:b=1:2 (2) a:b=1:3 (3) a Using a product made with a ratio of = 0, we visually measured the polishing surface every 10 seconds and measured the time until the entire surface was polished. (1) ... 50 seconds (2) ... 30 seconds (3) ... 30 seconds It was hot.

When we conducted a polishing experiment in the same manner as in Fig. 2 using the elastic media 10 shown in Fig. 3 removed at various angles of (1) 30° (2) 60° (3) 90°, (1) … 40 seconds (2) … 30 seconds (3) … It was 40 seconds.

The c:d ratio of the elastic intermediary body 10 in Fig. 4 was created under the following conditions: (1) c:d=1:60, (2) c:d=1:100, and (3) c:d=1:300. When a polishing experiment was carried out in the same manner as shown in Fig. 2, the polishing time was (1)...70 seconds (2)...40 seconds (3)...60 seconds.

In addition, when rotating the rotary pressure shaft 2 in only one direction, the center of the pressure adjustment part 9 of each elastic intervening body 10 in FIGS. The polishing effect can be improved by locating it not on the center line of the rotating pressurizing shaft 2, but slightly behind the center line (for example, at an angle of about 30 degrees from the center of the fixed part).

A conventional polishing material fixing part 1 in which five carbon-iron samples similar to those of the first embodiment are attached around the lower surface of a wide material fixing part 1 centered around a rotary pressure shaft 2.
, with a diameter of 205mmφ and a center hole diameter of 60mm.
φ, polished on one side of the surface plate under the conditions of 400 rpm and the polishing of the present invention (surface plate diameter
100mmφ to 130mmφ, surface plate rotation speed 400rpm, pressure force of rotating pressure shaft 2 400g/cm ² ), polishing time 30 seconds,
A comparative experiment was conducted using surface plate grain size #120 and GC water-resistant abrasive paper (Sumitomo 3M), and the results were as follows.

(a) The surface of the material to be polished before polishing had a roughness of around 20 μm.

(b) When using conventional equipment, uneven wear occurs after 30 seconds of polishing time, and 10 to 20% of the surface
It was only polished. It took over 20 minutes to polish the whole thing.

(c) When the present invention was used, the entire surface was polished in a polishing time of 30 seconds, and there were no comet tails or edges when only the surface plate was turned over.

A comparison experiment was conducted between polishing in which the surface plate 37 and workpiece 4 were rotated in only one direction, and polishing conditions in which each direction of rotation was reversed for a certain period of time. However, when the direction of rotation was reversed (see Figures 10 and 11), the comet tail disappeared and edge sagging (about 30 μm in Figure 9) occurred. ) also did not occur.

By employing the polishing method of the present invention as described above, the material to be polished 4 will not be in a state where the pressing force is eccentric in the direction of the rotary pressing shaft 2 with respect to the surface of the surface plate 37 as in the conventional case. The center hole 42 of the surface plate 37 where the eccentric pressurization center side and the opposite side are evenly distributed and pressurized and the polished material fixing part 1 rotates.
Since the rotation locus 43 partially overhangs the surface plate 37, the diameter of the surface plate 37 can be made smaller than the conventional rotation trajectory Y in which rotation polishing is performed on one side in the radial direction excluding the center of the surface plate 37. This allows the polishing machine to be made smaller. In addition, the rotary pressure shaft 2
The pressure adjustment part 9 is attached to the eccentric rotation fixed part fixed to the lower end of the
By attaching the material to be polished 4 via the elastic intervening body 10 having The applied eccentric pressurizing force is dispersed by the pressurizing adjustment part 9 of the elastic intermediary body 10, so that a uniform pressurizing force is applied to the material to be polished 4, and uneven wear of the polished surface can be prevented. Then, the rotation locus 43 of the material to be polished 4 that is rotatably polished on the surface plate 37 with an abrasive material arranged on its surface is set so that the center of the material to be polished 4 overhangs the center hole 42 that opens at the center of the surface plate 37. At the same time, a part of the material to be polished 4 is placed on the surface plate 3.
By overhanging outward from the outer peripheral edge of the surface plate 37, the amount of wear of the abrasive material on the surface plate 37 in the radial direction is made uniform, and edge sag on the worn outer surface of the material to be abraded 4 is prevented. Further, the polishing debris of the material to be polished 4 and the abrasion debris of the abrasive material are immediately removed from the center hole 42 and the outer peripheral edge of the surface plate 37 to prevent the polishing surface from being scratched by the polishing debris as much as possible, The occurrence of comet tails can be reduced. Furthermore, since the rotation locus during polishing is reversed forward and backward, rotation in one direction results in rotation loci in opposite directions, increasing the amount of polishing.In addition, the desired polishing state can be obtained in a short time. When rotating in the forward direction, the polishing speed decreases, allowing gentle polishing and almost eliminating comet tails.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a polishing machine used in the present invention, Figs.
The figure is an explanatory diagram showing the rotation locus of the polished material on the surface plate, Figures 8 and 9 are micrographs taken by the conventional polishing method, and Figures 10 and 11 are microscope photographs taken by the polishing method of the present invention. It is a diagram. A... Rotating and pressing device for material to be polished, B... Surface plate rotating device, 1... Fixing part for material to be polished, 2... Rotating and pressing shaft, 3... Drive device, 4... Material to be polished, 5 ... Sample fixing material, 8 ... Substrate, 9 ... Pressure adjustment section, 10
...Elastic intermediary bodies 10, 13...Compression parts 13, 15
...Pressure section, 20...Slide cores 20, 21
... Bearing, 22 ... Spindle sleeve,
27, 28... Spring stopper, 32...
Handle, 33, 34...Gear, 35...Motor, 37...Surface plate, 38...Accommodation section, 40...
Drive unit, 43...Rotation locus.

Claims (1)

[Scope of Claims] 1. The pressurizing force of a part to be polished is connected to a rotary pressure shaft eccentrically set with respect to the rotating axis of a polishing surface plate, and is transmitted to the polished material via an elastic intervening body. In the polishing method, a cover is attached to the eccentric rotation fixing part via an elastic intervening body having a pressure adjustment part that can evenly distribute the eccentric pressing force applied to the rotation pressure shaft side and the side remote from the shaft. The abrasive material is placed on a rotating surface plate having a circular hole in the center and the abrasive material arranged on the surface, and partially overhangs the center hole of the surface plate and partially overhangs outward from the outer periphery. A polishing method characterized by rotating and polishing the material to be polished along a rotational locus. 2. In a polishing method in which the pressurizing force of a part fixing the workpiece connected to a rotary pressure shaft set eccentrically with respect to the rotation axis of a polishing surface plate is transmitted to the workpiece through an elastic intervening body, The material to be polished, which is attached to the eccentric rotation fixing part via an elastic intervening body having a pressure adjustment part capable of evenly distributing the eccentric pressure applied to the rotation pressure shaft side and the side spaced from the shaft, is centered. On a rotating surface plate having a circular hole and an abrasive material arranged on the surface, the surface to be polished is rotated with a rotation locus that partially overhangs the center hole of the surface plate and partially overhangs the outer periphery outward. A polishing method characterized by polishing the material and one or both of the surface plates by inverting them for a certain period of time or at a certain number of rotations.