JPH0596468A - Ultra-precision mirror surface processing method - Google Patents

Abstract

(57) [Summary] [Purpose] An ultra-precision mirror surface processing method in which ultra-fine powder is brought into fluid contact with the surface to be processed of a workpiece, and mirror surface processing proceeds without causing distortion, cracks or thermal alteration. is there. [Structure] A long cylindrical workpiece is disposed in the vicinity of a workpiece placed in a suspension in which ultrafine powder is dispersed, in parallel with the workpiece, and the workpiece is processed. While rotating while pressing with a constant load, the workpiece is relatively translated in a direction inclined by a predetermined angle within a range of 0 to 90 degrees with respect to the axial direction of the workpiece to form an ultrafine powder. The surface processing is advanced by the interaction at the processing surface interface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a mirror-finishing process in which ultrafine powder is brought into fluid contact with a processed surface of a workpiece such as a silicon wafer and a thin film substrate without causing distortion, cracking or thermal alteration. The present invention relates to a super-precision mirror-surface processing method for advancing the process.

[0002]

2. Description of the Related Art Conventionally, a suspension in which ultrafine powder is dispersed is caused to flow along a machined surface of a workpiece to bring the ultrafine powder into contact with the machined surface under substantially no load, Ultra-precision mirror surface by so-called EEM (Elastic Emission Machining), which removes processed surface atoms in the order close to atomic units by the interaction (a kind of chemical bond) at the interface between the ultrafine powder and the processed surface. Processing is already known.

In the conventional processing using EEM, as shown in FIG. 6, while the processing sphere a is pressed against the processing surface c of the object b to be processed, it is rotated by the rotation driving means d to suspend the suspension in the vicinity of the processing surface. A flow is generated, and the spherical surface a is scanned over the entire surface to be machined, and spot machining marks formed in a minute region on the surface to be machined are made continuous to precisely machine the entire surface.

However, when the above-mentioned processing sphere is used, the amount of processing can be changed by changing the scanning speed at each point on the processing surface to form an uneven shape. Since the processing marks are very small, there is a problem that it takes a long processing time for a workpiece having a large area and the smoothness of adjacent spot processing marks in the direction orthogonal to the scanning direction is slightly inferior.

Therefore, it can be easily considered that a large area can be processed in a short time by replacing the spherical body with a circular rotary body. However, in the process of manufacturing this rotating body,
Innumerable striations that inevitably affect machining are inevitably formed in the circumferential direction of the surface. That is, the streaks appear by transferring minute irregularities formed when the inner surface of the mold is cut at the time of manufacturing the mold for molding the rotating body, or when the surface of the rotating body is finished, It is formed in the process of polishing or cutting the surface while rotating. As a result, when the rotation axis of the rotating body and its scanning direction are made orthogonal,
The presence of these scratches reduces the mirror surface precision of the machined surface.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present invention is to solve the problem that when the flat machining surface of a workpiece is mirror-finished, the machining area per unit time is significantly increased. It is an object of the present invention to provide an ultra-precision mirror surface processing method capable of performing mirror surface processing with high accuracy of 0.1 μm or less.

[0007]

In order to solve the above-mentioned problems, the present invention provides a vicinity of a work having a flat work surface in which a super fine powder is uniformly dispersed in a suspension. In addition, a long columnar processed body is arranged parallel to the machined surface, and the machined body is rotated while being pressed against the machined surface with a constant load so that the machined surface is formed in a minute region of the machined surface. A suspension flow is generated in a direction along the axis of the workpiece, and further, 0 to
An ultra-precision mirror surface processing method in which the workpiece is relatively translated in a direction inclined by a predetermined angle within a range of 90 degrees, and surface processing is progressed by interaction between the ultrafine powder and the processing surface interface. Configured.

Further, in the vicinity of a work having a flat work surface in which a super fine powder is uniformly dispersed, a long cylindrical work is formed in parallel with the work surface. A body is placed, and the processed body is rotated while being pressed against the processed surface with a constant load to generate a suspension flow in a direction along the surface in a minute region of the processed surface. Is relatively reciprocally moved in the axial direction, and the workpiece is relatively moved in a direction substantially orthogonal to the axial direction of the rotating body to perform surface processing by interaction between the ultrafine powder and the processing surface interface. An advanced ultra-precision mirror finishing method was constructed.

As the processed body, a processed body in which a cylindrical rotating body made of polyurethane is arranged around the shaft is used.

Further, the ultrafine powder has a particle size of 10 ^-9 to 10
^-6 m of powder was used.

[0011]

The ultra-precision mirror-surface machining method of the present invention having the above-mentioned contents is achieved by rotating a long cylindrical workpiece while pressing it against a flat machining surface of a workpiece with a constant load.
A suspension in which ultra-fine powder is uniformly dispersed is wound between the processed body and the processed surface, and the ultra-fine powder is successively passed in the direction along the processed surface to form the ultra-fine powder and the processed surface. Due to the interaction of a kind of chemical bond at the surface interface, the constituent atoms of the processed surface are removed on the order of atomic units and surface processing is performed without any altered layer. 0 as a standard
Influence of innumerable ridges and valleys formed along the circumference of the workpiece by parallel translation of the workpiece in a direction inclined by a predetermined angle within a range of 90 degrees due to the limit of processing accuracy during manufacturing of the workpiece Except for that, ultra-precision mirror surface processing is performed.

Further, the workpiece is reciprocally moved in the axial direction relatively and the workpiece is moved in parallel in a direction substantially orthogonal to the axial direction of the workpiece, so that the circumference of the workpiece is moved. The mirror surface processing is performed by similarly removing the influence of the uneven lines.

When polyurethane is used around the processed body, the ultrafine powder is effectively caught in the minute gap between the processed body and the processed surface without damaging the processed surface. The ultrafine powder is supplied one after another.

Furthermore, by using a powder having a particle size of 10 ^-9 to 10 ^-6 m as the ultrafine powder, it is possible to perform mirror finishing with an accuracy of 0.1 μm or less.

[0015]

The present invention will be further described in detail with reference to the embodiments shown in the accompanying drawings.

FIG. 1 shows the principle of the processing method of the present invention. In the figure, 1 is a workpiece, 2 is a workpiece, and 3 is an ultrafine powder.

A cylindrical body 1 made of a flexible synthetic resin such as polyurethane and a workpiece 2 having a flat surface 4 are suspended in which ultrafine powders 3, ... Are uniformly dispersed. The workpiece 2 is placed in the suspension 5 so that the workpiece 2 can be moved in parallel, the workpiece 1 can be rotated, and the workpiece 4 can be pressed with a constant load W. The suspension 5 is wound between the processed body 1 and the processed surface 4 by
A local suspension flow that flows in the direction along is generated, and accordingly, the ultrafine powder 3 in the suspension 5 is in contact with the workpiece 2 and the processed surface 4 and the processed body 1 one after another. The fine irregularities on the processed surface 4 are removed by a chemical interaction (a kind of chemical bond) at the interface between the processed surface 4 and the ultrafine powder 3 at a size close to the atomic level. The mirror surface processing is advanced. In FIG. 1, the side of the workpiece 1 facing the workpiece 2 is shown as slightly deformed by the load W and the fluid dynamic pressure, and the flow of the suspension 5 generated by the rotation of the workpiece 1 is shown. It is shown that the ultrafine powders 3, ... Are moving along the streamline.

Here, the gap between the processing body 1 made of polyurethane and the processing surface 4 of the workpiece 2 is the load W applied to the processing body 1.
And the fluid dynamic pressure of the suspension 5 are automatically kept stable, and if the flow state and the dispersion state of the ultrafine powder 3 are stable, the number of working powders per unit time is also stable,
The processing amount per unit time is also stable. Therefore, the processing amount at an arbitrary position can be accurately controlled by the moving speed or the stop time in the relative parallel movement of the workpiece 1 and the workpiece 2, and high-precision mirror surface processing can be performed.

Further, in the processing method of the present invention, the combination of the work piece 2 and the ultrafine powder 3 to be used causes a large change in the working speed in the range far exceeding 1000 times. Ultrafine powder 3 with optimum physical properties for processing 2
Is desired to be selected. For example, when a silicon wafer (Si) is selected as the workpiece 2, the ultrafine powder 3 that is most suitable for the processing is ZrO obtained by crushing naturally occurring rough stones.
₂ powder, and artificially added Zr (OH) ₄ at 850 ℃
It is also possible to slightly lower the processing speed by using a powder synthesized by firing at 900 ° C., adding 35% of SiO ₂ and then firing at 900 ° C., and synthesizing as a zircon crystal having incomplete crystallinity as a whole. The particle size of the ultrafine powder 3 is also selected according to the state of the processed surface 4 of the workpiece 2 and the processing accuracy, and usually the particle size is
Powders with a size of 10 ^-9 to 10 ^-6 m are used, but if the particle size is 10 ^-9 m or less, it is almost impossible due to the limitation of powder production, and if the particle size is 10 ^-6 m or more, the processing accuracy is high. Therefore, from the principle and purpose of the processing method of the present invention, the ultrafine powder 3 having the above particle size range is used.

Next, to describe the present invention in more detail, the processed body 1 has a structure in which a polyurethane rotating body 7 is arranged around a shaft 6 as shown in FIG. 7
Innumerable striations 8 that adversely affect the processing in the circumferential direction of the surface of
Is inevitably formed. That is, the streaks 8 are formed by transferring the minute irregularities formed when the inner surface of the mold is cut during the manufacture of the mold for molding the rotating body 7. Alternatively, the streaks 8 are formed in the step of surface polishing or cutting while rotating the rotating body 7 when finishing the surface of the rotating body 7. When the workpiece 1 is rotated due to the existence of the streaks 8 and the workpiece 2 is relatively translated in the direction orthogonal to the axis 6 of the workpiece 1, and the entire surface 4 is machined. , Innumerable linear scratches 9 on the processed surface 4
Is transferred, and a mirror surface having high precision smoothness cannot be obtained.

Therefore, as shown in FIG. 3, the processing apparatus for carrying out the ultra-precision mirror surface processing method of the present invention supports the shaft 6 of the processed body 1 by the bearings 10, 10 and at one end of the shaft 6. A belt 14 wound around a fixed driven pulley 11 and a drive pulley 13 of a motor 12 makes it rotatable, and a table 15 for mounting the workpiece 2 is placed close to the workpiece 1 and the machining is performed. A direction in which the body 1 or the table 15 is brought closer to each other is relatively movable in parallel to a predetermined angle within a range of 0 to 90 degrees with respect to the axial direction of the body 1, preferably about 45 degrees. In addition, it has a pressing means (not shown) for pressing with a constant load, and the processed body 1 and the table 15 are arranged in a suspension 5 in which ultrafine powders 3, ... Are uniformly dispersed. In this embodiment, the workpiece 1 is not rotatable at a fixed position and the table 15 is moved in parallel. However, the table 15 is fixed, and the workpiece 1 may be rotated and translated in parallel. Of course, it is possible. Further, as the means for transmitting the rotational force of the motor 12 to the shaft 6 of the processed body 1, another chain or gear may be used. Then, while rotating the machined body 1, the machined surface 4 of the work piece 2 is pressed with a constant load, and further the table 15 is translated in the tilt direction, so that the influence of the scratches 8 on the surface of the machined body 1 is completely eliminated. The mirror surface is processed with high precision without receiving it.

In the embodiment shown in FIG. 4, the workpiece 1 is reciprocally moved in the axial direction relative to the table 15 on which the workpiece 2 is mounted, and the table 15 is moved along the axis of the workpiece 1. This is a processing method in which the workpiece 8 is relatively parallel moved in a direction substantially orthogonal to the direction so as not to be affected by the scratches 8 on the surface of the processed body 1. Further, specifically, the shaft 6 of the processed body 1 is a bearing.
The shaft 6 is rotatably and slidably supported by 10 ,.
A moving means 16 for reciprocating the shaft 6 is linked to one end of the shaft 6, and a driven pulley 11 is slidably mounted on a spline shaft 17 formed on a part of the shaft 6 to drive the motor in the same manner as described above.
It is rotationally driven by 12, and the table 15 is adapted to be moved in parallel in a direction substantially orthogonal to the shaft 6 by an appropriate means. As a result, the axial movement of the workpiece 1 and the substantially orthogonal direction of the table 15 are performed. The movements are combined to move relative to the axial direction in the inclination direction for processing.

Further, the embodiment shown in FIG.
An example of a loading mechanism 18 that attaches the workpiece 2 to the table 15 and presses the workpiece 2 against the rotating body 7 with a constant load, and a scanning mechanism 19 that relatively moves the workpiece 2 with respect to the rotating body 7. Shows.

The load mechanism 18 is provided with a guide tool 21 such as a slide bearing inside an opening 20 formed through the table 15, and a vacuum chuck 22 is attached by the guide tool 21 so as to be retractable downwards. A constant load F is applied from above the weight of the chuck 22 and the vacuum chuck 22 with a heavy weight, a spring, or a combination thereof. The vacuum chuck 22 is provided with a space portion 23 inside, a large number of suction holes 25, ... Are provided in a mounting surface 24 on the lower surface, and a flexible hose 26 connected to the space portion 23 sucks air to suck the workpiece on the mounting surface 24. 2 is adsorbed and fixed. In this way, the work piece 2 fixed to the vacuum chuck 22 to which a constant load F is applied is pressed by the constant load to the rotating body 7 arranged in the vicinity below the table 15.

The scanning mechanism 19 includes one or a plurality of dovetail grooves 2 on either the table 15 or the fixed portion 27 that is in contact with the table 15.
8 and 28 are formed, and a dovetail 29, which is slidably engaged with the dovetail groove 28, is projectingly provided on the other side. Then, the table 15 is moved with respect to the fixed portion 27 by an appropriate means.

Further, the surface of the rotating body 7 may be worn or slightly damaged during long-time processing, but it is necessary to restore the surface of the rotating body 7 after the processing. Further, there are cases where it is desired to adjust the surface of the rotating body 7 to a predetermined accuracy before processing. Therefore, in this embodiment, a guide shaft 30 parallel to the shaft 6 is arranged near the rotary body 7, and a chuck 31 movable along the guide shaft 30 and movable in a direction orthogonal to the rotary body 7 is provided. However, an ultra-precision cutting device in which the chuck 31 is equipped with a cutting tool 32 capable of highly accurate cutting is also provided.

As described above, according to the processing method of the present invention, it is possible to process the final surface of a functional material or the like which makes full use of the physical properties of the material, for example, for a laser gyro that requires a high-performance surface. It is possible to perform mirror finishing such as mirrors with no processing-altered layer and with an accuracy of the order of 0.1 nm.

[0028]

According to the ultraprecision mirror surface processing method of the present invention as described above, a work piece is placed in a suspension in which ultrafine powder is uniformly dispersed, and the work piece is processed. The long cylindrical work piece is pressed against the surface while rotating it while pressing it with a constant load, and the work piece and the work piece are relatively moved in parallel, whereby the ultrafine powder in the suspension is processed. The processed surface is removed on the order of atomic units by a kind of chemical bond interaction between the processed surface and the interface of the ultrafine powder, and dislocations, cracks and thermal alteration layers are completely removed from the processed surface. It is possible to perform ultra-precision mirror surface machining on the atomic order, which is the smallest unit, without generating it, and further, to machine the workpiece in a direction inclined by a predetermined angle within the range of 0 to 90 degrees with the axial direction of the workpiece as a reference. Since the parallel translation is performed, the surface of the workpiece is assumed in the manufacturing assumption of the workpiece. It can be processed without being circumferentially the effect of inevitably formed streaks at all, therefore it can be processed in a short time processing surface of large area.

The same effect as described above can be obtained when the workpiece is reciprocally moved in the axial direction and the workpiece is relatively moved in the direction substantially orthogonal to the axial direction of the workpiece. At the same time, by changing the reciprocating speed of the workpiece and the parallel moving speed of the workpiece, the moving direction of the workpiece with respect to the axial direction of the workpiece can be substantially changed.
It is possible to easily set delicate processing conditions.

Furthermore, by using a machined body in which a cylindrical rotating body made of polyurethane is arranged around the shaft, the suspension is efficiently supplied between the machined body and the workpiece without damaging the machined surface. Therefore, the processing efficiency of the ultrafine powder can be improved.

If ultrafine powder having a particle size of 10 ⁻⁹ to 10 ⁻⁶ m is used, highly precise mirror finishing of 0.1 μm or more required for silicon wafers can be performed.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view showing a processing principle of an ultraprecision mirror surface processing method of the present invention.

FIG. 2 is a simplified perspective view showing a state in which a scratch is generated on a processing surface of a workpiece by a scratch having a circumferential direction of a surface of a workpiece.

FIG. 3 is a simplified plan view showing a typical embodiment of the ultra-precision mirror surface processing method of the present invention.

FIG. 4 is a simplified plan view showing another embodiment of the present invention.

FIG. 5 is a simplified cross-sectional view showing an example of a load and scanning mechanism.

FIG. 6 is a simplified perspective view showing a conventional example.

[Explanation of symbols]

1 Workpiece 2 Workpiece 3 Ultrafine powder 4 Machining surface 5 Suspension 6 Shaft 7 Rotating body 8 Streak 9 Streak 10 Bearing 11 Driven pulley 12 Motor 13 Drive pulley 14 Belt 15 Table 16 Moving means 17 Spline shaft 18 Load mechanism 19 Scanning mechanism 20 Opening 21 Guide tool 22 Vacuum chuck 23 Space 24 Mounting surface 25 Suction hole 26 Flexible hose 27 Fixed part 28 Dovetail groove 29 Dovetail 30 Guide shaft 31 Chuck 32 bytes

Claims (4)

[Claims] 1. A long cylindrical processing in the vicinity of an object to be processed having a planar processing surface, which is arranged in a suspension in which ultrafine powder is uniformly dispersed, in parallel with the processing surface. A body is placed, and the processed body is rotated while being pressed against the processed surface with a constant load to generate a suspension flow in a direction along the surface in a minute region of the processed surface. The workpiece is relatively moved in parallel in a direction inclined by a predetermined angle within a range of 0 to 90 degrees with reference to the axial direction, and the surface processing is advanced by the interaction between the ultrafine powder and the processing surface interface. An ultra-precision mirror surface processing method characterized by the following. 2. A long columnar processing which is parallel to the processed surface and is provided in the vicinity of a workpiece having a planar processed surface which is disposed in a suspension in which ultrafine powder is uniformly dispersed. A body is placed, and the processed body is rotated while being pressed against the processed surface with a constant load to generate a suspension flow in a direction along the surface in a minute region of the processed surface. Is relatively reciprocally moved in the axial direction and the workpiece is relatively moved in a direction substantially orthogonal to the axial direction of the workpiece to perform surface processing by interaction between the ultrafine powder and the processing surface interface. An ultra-precision mirror surface processing method characterized by being advanced. 3. The ultra-precision mirror-surface processing method according to claim 1, wherein the processed body is a processed body having a cylindrical rotating body made of polyurethane arranged around a shaft. 4. The ultrafine powder has a particle size of 10 ⁻⁹ to 10 ⁻⁶ m.
The ultra-precision mirror surface processing method according to claim 1 or 2, wherein the powder of (1) is used.