JP2000141207A - Precision surface working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the lapping and polishing processes and serially execute the silicon wafer coarsening work to the super precision mirror finish work only by the polishing work by controlling the pressure for the operation of the precision surface working machine by combining a servomotor device and a super magnetostrictive actuator. SOLUTION: A servomotor device 8 executes the positioning of a work piece 3 to a diamond grinding wheel 5 by driving an X-Y table 1 in the X axial direction. In some zone, the pressure control is executed to perform the control necessary for the rough working by the diamond grinding wheel 5. The super magnetostrictive actuator in a hybrid actuator 9 controls a fine cutting quantity necessary for the precision working of the work piece by the diamond grinding wheel 5. By using both devices, a silicon wafer as the work piece 3 is correctly positioned to the diamond grinding wheel 5, and the X-Y table 1 is finely and correctly fed in the X-axial direction for the cutting necessary for the grinding work, to control the fine cutting quantity and the working pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for precisely processing a surface of an article requiring an extremely precise surface, such as a silicon wafer, a magnetic disk substrate, or a substrate for a crystal oscillator. The present invention relates to a so-called super-machining machine, which is a precision plane machining apparatus that performs processing from machining to ultra-precision mirror finishing including final ductile mode machining consistently and efficiently.

[0002]

2. Description of the Related Art In recent years, there has been a need for downsizing, high performance, high productivity, and low cost of so-called electronic devices such as computers, and ICs occupying important parts thereof have been required.
There is an urgent need to increase storage capacity and reliability and reduce production costs for LSIs and super LSIs.
At the same time, there is an urgent need for energy saving and energy saving in the entire industry. Under these circumstances, silicon wafers, magnetic disk substrates, substrates for crystal oscillators, etc., which are the raw materials for these elements and the parts supporting the periphery thereof, have dimensional accuracy and / or surface roughness at the processing stage. The demand for improvement is remarkable. On the other hand, there is also a need to respond to demands for lowering the cost of the processing process and dramatically improving productivity, and therefore, it is necessary to develop processing methods and equipment based on completely new ideas. I have.

Electronic components such as ICs, LSIs, and super LSIs, which are made of semiconductor materials such as silicon single crystals, are mirror-finished on wafers obtained by slicing single-crystal ingots of silicon or other compound semiconductors.
It is manufactured based on small chip-shaped semiconductor element chips into which a large number of minute electric circuits are written and divided, and the silicon wafer with mirror finish is manufactured through the following series of manufacturing processes. Was common. That is, after performing the outer peripheral grinding of the silicon single crystal ingot manufactured by the single crystal pulling method, for example, performing orientation flat processing for positioning in the crystal direction, slicing with an inner peripheral blade saw or a wire saw, and as-cutting. Get a wafer. This as-cut wafer is chamfered on the outer peripheral portion by beveling, and then is finished to have uniform thickness, parallelism, flatness, straightness and a certain surface roughness by double-sided lapping. The obtained wrapped wafer is subjected to an etching process with an acid or an alkali to remove a processing damage layer caused by the lapping, and then a mirror finish by pre-polishing and polishing. The mirror surface wafer obtained here must have excellent surface roughness and shape accuracy. The surface roughness Ra of the final mirror finished surface of the 30 cm (12 inch) wafer is desirably 1 nm or less, the flatness is 0.3 μm / 30 cm or less, and the processing amount from the as-cut wafer to the final mirror surface wafer is about 60 μm on both sides. It is.

[0004] The main unit operations in each of the above-mentioned processing steps, specifically, operations such as lapping, etching, pre-polishing and polishing are all performed by separate batch-type mechanical devices. During that time, the silicon wafer, which is the workpiece, is moved and conveyed manually or is performed by an automatic conveyance robot. In particular, in recent years, there has been a remarkable tendency to increase the size of the wafer itself due to a demand for improvement in productivity, and a wafer having a large diameter such as 8 inches or 12 inches has been produced. The above-described main unit operations such as lapping, pre-polishing, and polishing have conventionally been generally performed by simultaneously processing a plurality of workpieces with a large-sized processing machine. However, although the size of wafers has been increasing and the size of the equipment has been increasing, the size of the equipment has been limited due to its handling characteristics. There is also difficulty in making the process more precise, and recently, many studies have been made on what is called a sheet-like method, in which processing is performed one by one.

Conventionally, processes such as lapping, pre-polishing, and polishing involve arranging a platen on both upper and lower surfaces or one of the surfaces, and setting a workpiece between or on the surfaces, and containing abrasive grains as abrasives. It is performed by a method in which the surface plate and the workpiece are pressed and rotated while supplying the processing liquid quantitatively to improve the surface roughness by the action, and the processing amount is controlled by movement control. In actual processing, the surface of the workpiece is rubbed or rubbed by the action of a working fluid containing abrasive grains, rotation of the platen, and a load (working pressure), and the processing progresses. Such a load is an important factor for smoothly, uniformly, accurately and efficiently processing the desired target numerical value.
In this case, the load applied to the workpiece is, for example, a load on the upper platen or, in the case of a single-sided machine, a method of performing only by its own weight of the pressure plate for gripping the workpiece, and the lifting load is adjusted by the reverse pressure of the air cylinder. There is a method of controlling the applied load only by the action of the air cylinder (for example, Japanese Patent Publication No. 29470/1990). The quality of the control depends on the shape accuracy, processing efficiency and surface roughness of the processed surface of the workpiece. It is an important factor that affects the quality. However, since these processes are basically processes of a motion control system using a constant load, unlike the process of a forced cutting system using a diamond grindstone, for example, extremely strict control of the feed amount (cutting amount) is required. Not required.

[0006] In the case of lapping, the surface to be directly machined is usually a cast iron platen having a certain thickness, in which, for example, a lattice-shaped groove is cut on a plate, and a silicon wafer or the like is interposed therebetween. After the required work load (working pressure) is applied, the platen and the work are rotated, and the work is performed by the action of the working fluid containing abrasive grains and the abrasion and rubbing action of the rotation. Progresses. Usually, the processing pressure in the lapping process is about 100 to 300 gf / cm ² , and the abrasive grains used are alumina series of about 800 to 2000. In the pre-polishing or polishing process, non-woven fabric, fabric, synthetic resin foam,
The same processing is performed using a homogeneous sheet-like thin layer made of synthetic leather or a composite thereof, that is, a surface plate to which a polishing pad is attached. Usually, the processing pressure in the polishing processing is about 100 to 300 gf / cm ² , and the abrasive used is colloidal silica having a size of submicron to several microns. Here, a double-sided processing machine is used until pre-polishing, and a single-sided processing machine is used for polishing.

Conventionally, as described above, in the conventional lapping, polishing is usually performed in a so-called brittle mode using a surface plate and free abrasive grains. In polishing, a soft polishing pad and a soft polishing pad are used. The processing proceeds by mechanochemical polishing using a processing liquid containing colloidal silica as free abrasive grains. In recent years, this method has been used in a ductile mode by a grinding method using a method using an elastic grindstone or a method using a diamond grindstone (for example, Japanese Patent Application Laid-Open No. 62-99072) as shown in Japanese Patent Publication No. 6-71708. Processing, i.e., processing by grinding, has been proposed, but in any of these cases, the occurrence of a work-affected layer having irregular and locally deep portions due to abrasive scratches is remarkable, and this layer is removed by etching. However, the potential distortion was not completely removed, and there was still a problem in practical use. Further, the processing in the ductile mode by the above-described grinding, which covers the lapping processing area, does not cover the polishing area.

[0008] However, in the method using a diamond grindstone, the high grinding power of the diamond abrasive grains and the possibility of increasing the efficiency of the work due to the high grinding power are difficult to dispose of. While changing the processing conditions, a method has been attempted in which the processing is performed consistently from rough processing to final mirror finish processing. Furthermore, research and development of a processing method that uses electrolytic in-process dressing in combination with the aim of maintaining the processing performance and improving the processing efficiency of diamond whetstones (eg, 1988, 10, 203, 1988). Is also thriving. These are all intended to use a high-count diamond wheel, and to perform an integrated processing of a silicon wafer in a single wafer mode.

[0009] Grinding using these diamond grindstones involves three main movements: rotation of the grindstone, feed of the spindle supporting the grindstone, and positioning of the workpiece. It is possible to perform precision machining by controlling these with high precision.However, in order to perform consistently from rough machining to machining in the ultra-precision area with one device and machine, one of the major movements described above In addition, it is necessary to control the feed of the spindle in a wide range with extremely high accuracy. Conventionally, for the control of this spindle in general cutting or grinding, for example, a method using a servomotor is often used, but it is not sufficient for the purpose of accurately covering a wide range, that is, from a low pressure region to a high pressure region. However, it was hard to say that it was sufficient especially for processing in a low-pressure region where ultra-precision processing was performed.

Conventionally, as a means for precisely controlling the position and speed of a machine tool or an industrial robot, there has been a method of using the above-mentioned servomotor, and there is an idea of applying this method. Although there is no particular problem with respect to, control of a low-pressure region for the purpose of ultra-precision processing cannot be covered and is not sufficient. Further, a method of using a PZT actuator or a giant magnetostrictive actuator as a means for minute displacement and positioning of a precision machining device such as a precision lathe, drilling machine, and honing machine has already been disclosed (Japanese Patent Application Laid-Open No. 64-34631). The giant magnetostrictive actuator referred to herein is a giant magnetostrictive material (USP3, USP3) made of a single rare-earth / iron-based alloy, for example, an alloy of terbium, dysprosium, and iron.
949, 351) applied to the actuator as a Joule effect (dimensional change due to a magnetic field).
It is characterized by extremely high resolution and accurate minute displacement, and can be used as a vibrating element depending on conditions. The characteristics of this giant magnetostrictive actuator with respect to other micro actuators are as follows: elastic deformation is as large as 10 to 100 times, elastic energy is as large as 20 to 50 times, and response time is μs to
ns and low power consumption.

[0011]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present inventors have made intensive studies and have used a very high-count diamond wheel. By performing only rotation about the X axis and using a servo piezoelectric device and a giant magnetostrictive actuator together as a feed control means for a work axis that supports a work table on which a workpiece is gripped, the high pressure area of the work axis is 1 kgf. / Cm
² to low pressure region 0.01 gf / cm ² , 100 μm /
Enables high-precision control over a wide range with a precision of step to 2 nm / step, and thereby enables a single device / machine to perform from rough processing of the silicon wafer to be processed to ultra-precision mirror finishing. The inventors have found that the present invention is possible, and have completed the present invention. Accordingly, an object of the present invention is to provide a precision plane processing machine capable of performing all steps from rough processing to ultra-precision mirror finishing of a silicon wafer to be processed by only grinding processing without lapping and polishing steps. The purpose is to provide.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a grinding wheel, a grinding wheel mounting device for mounting and rotating the grinding wheel,
What is claimed is: 1. A precision plane processing machine comprising a grinding wheel shaft for supporting the mounting device, a work table for gripping a workpiece, and an XY table for supporting the work table. This is achieved by a precision plane processing machine characterized by being performed by a combination of a device and a giant magnetostrictive actuator. The aforementioned pressure control is 10
In the range of gf / cm ² or more, the operation is performed by a servo motor device, and the gage is controlled to 10 gf / cm ² or less and 0.01 gf / cm ²
In the range up to, this is performed by a giant magnetostrictive actuator. Further, in the above-mentioned precision plane processing machine, it is assumed that the grinding wheel uses a diamond cup type grinding wheel having an abrasive grain size smaller than # 3000.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The external appearance of a precision flattening machine according to the present invention is as shown in the sectional view of FIG. 1 and the plan view of FIG. 1 and 2, reference numeral 1 denotes an XY table. Reference numeral 2 denotes a work table mounted on an XY table, which is rotatable in forward and reverse directions around an X axis. A silicon wafer as a workpiece 3 is mounted and fixed on a work table 2. A cup-shaped diamond wheel 5 is mounted on the surface of the disk-shaped wheel mounting device 4. The diamond grindstone 5 can rotate around the X-axis at any speed from low speed to high speed in any direction in the normal or reverse direction according to the movement of the mounting device 4. The mounting device 4 is supported by a grindstone shaft 6. The grindstone shaft 6 is attached to a spindle head 7, and a drive motor for rotating the grindstone 5 is installed in the spindle head 7. XY table 1 is Y
A servo motor device 8 which has a structure capable of arbitrarily moving in the axial direction and is precisely controlled by a computer is provided. The servo motor device 8 is X-
The Y table 1 is driven in the X-axis direction to position the workpiece 3 with respect to the diamond grindstone 5, and the pressure is controlled in a range from 10 gf / cm ^{2 to} 1 kgf / cm ^{2 for} rough machining by the diamond grindstone. Perform necessary control. The giant magnetostrictive actuator housed in the hybrid actuator 9 controls a minute cut amount necessary for precision machining of a workpiece by a diamond grindstone, and the corresponding range is 0.01.
Ｇ10 gf / cm ² , whereby about 1 nm〜1
A minute cut can be made in the range of 0 μm. By using both of these devices together, X for performing accurate positioning of the silicon wafer as the workpiece 3 with respect to the diamond grindstone 5 and performing cutting required for the grinding by the silicon wafer can be obtained.
-The minute feed in the X-axis direction of the Y table 1 is accurately performed in the range of about 1 nm to about 100 μm, and the minute cut amount and the processing pressure are controlled. The precision planar processing machine of the present invention is operated by rotating the grindstone and driving the device for positioning and pressure control of the workpiece.

The diamond cup type grindstone used in the present invention generally indicates the following. That is, the grain size of the abrasive grains is JIS-R6001 (the grain size of the abrasive)
Is finer than 3000 in the standard, that is, dv-5
0 value is 4.0 ± 0.5 μm or less. If the grain size of the abrasive grains is coarser than this, the surface obtained is not a mirror surface and can no longer be said to be a region for ultra-precision processing. The method for fixing the diamond abrasive grains is not particularly limited, but it is preferable to use a resinoid resin bond grindstone bonded with a phenol resin or a metal bond grindstone bonded with a special alloy. It is also effective to apply a nickel / phosphorous electroless plating layer on the surface of the grindstone in order to increase the bonding property of the abrasive grains. In addition, since the above-described binder is mixed with ultra-fine cluster diamond particles having an average particle diameter of 0.1 μm or finer, it is possible to prevent the diamond particles serving as abrasive grains from falling off and to increase the life as a grinding stone. it can. The shape of the grindstone is an annular cup type, and there is a grindstone use surface on the outer peripheral edge. In other words, it is characterized in that the grindstone surface having a relatively narrow width rotates and comes into contact with the surface of the workpiece.

The essential point of the present invention is that when the above-mentioned cup-shaped grindstone is brought into contact with a silicon wafer as a workpiece and processed, the pressure control and the feed of the shaft are not performed by the grindstone shaft but by the grinding of the workpiece. The gist is that the movement is performed by the movement of the XY table. In other words, it has been found that performing high-speed rotation around the X-axis, precise feeding in the X-axis direction, and pressure control on the same axis has a problem in terms of the precision of ultra-precision machining. The feature of the present invention lies in that the pressure in the X-axis direction of the XY table is controlled with high precision separately from the rotation of the grinding wheel, and the feed and the cutting amount of the grinding wheel are performed in accordance with the content of the intended processing. It is.
That is, a computer-controlled servomotor device is installed in the spindle head connected to the XY table, and a giant magnetostrictive actuator is installed on the work table. The workpiece is finely fed in the X-axis direction to perform the necessary cutting. The servo motor device here is a DC or AC motor as a drive source,
While the position of the work axis is detected and fed back to the work axis, feed control of the work axis is performed using a computer, and in the present invention, it is 300 gf / cm ² to 1 g / cm ^2.
Control is performed in a pressure range up to 0 gf / cm ² . The change of the pressure may be stepwise or may be a continuous stepless speed change method. Control of pressure ranges below this is inaccurate and not suitable. The control of the XY table in the X-axis direction by the servo motor device is a region where a minute displacement at a relatively high pressure is required to be fed with high precision, specifically, a processing region corresponding to a conventional lapping process.

The giant magnetostrictive actuator referred to in the present invention is:
A giant magnetostrictive material, which is a polycrystalline or single crystal alloy with a specific ratio of a specific rare earth element and an iron group element consisting of nickel, cobalt, and iron, and undergoes a strong dimensional change when a magnetic field is applied, is used as an actuator. Things. FIG.
FIG. 3 is an explanatory sectional view of a giant magnetostrictive actuator used in the present invention. A rod 10 made of a giant magnetostrictive material is placed at the center, and its periphery is surrounded by a driving coil 11. One end of the rod 10 is fixed, and the other end is free and abuts on the output terminal 12. The output terminal 12 is urged by a spring 13 and can freely follow the displacement of the rod 10. 14 is a permanent magnet. Coil 1
A cooling water jacket 15 is disposed around the circumference 1. A magnetic field is generated by passing an electric current through the driving coil, and the giant magnetostrictive material rod 10 is deformed by the Joule effect, which is transmitted to the output terminal 12 and acts as an actuator. The cooling water jacket 15 is arranged to minimize the dimensional change due to temperature. The control range of the main shaft 6 by this giant magnetostrictive actuator is 10 gf
/ Cm ² as an upper limit, a pressure range up to 0.01 gf / cm ² , and a cut amount in a range of 1 to 100 nm, that is, a region where low pressure and extremely small displacement feed are required with high precision, specifically Is a processing area corresponding to a conventional polishing step.

A servo motor device controls a silicon wafer, which is a workpiece to be gripped and fixed on a worktable, and in a region where processing is performed by a diamond grindstone, first, a forced cutting amount with respect to the silicon wafer is set relatively high.
After obtaining sufficient shape accuracy by processing at high pressure, the cutting depth is slightly reduced, the affected layer is removed, and the surface roughness is improved, but the generation of the affected layer is suppressed and the thickness of the layer is reduced. In order to minimize this, it is preferable to reduce the working pressure continuously and gradually. In the region where the cutting depth is controlled by the giant magnetostrictive actuator, the forced cutting depth for the silicon wafer is set to an extremely small amount, and the surface roughness Ra of 1 nm or less can be obtained with a removal amount of several μm by processing at a low pressure. The actual processing is based on the grinding force of the cup-shaped diamond grindstone, which is greatly affected by the number of revolutions of the grindstone. The higher the speed, the lower the grinding force.

In actual processing, the outer periphery of a silicon single crystal ingot is ground and subjected to orientation flat processing, and then, for example, an ascut wafer finished to a predetermined thickness using a wire saw is chamfered at the outer peripheral edge portion. The processed material (beveling) is used as a starting material, that is, the workpiece 3. The workpieces conveyed to a separately placed supply table (not shown) are gripped and lifted one by one by an arm (not shown) provided with a means such as a vacuum chuck, for example.
-Transferred and placed on the work table 2 of the Y table 1. At the time of mounting, the XY table 1 has been moved in the Y-axis direction, and is at a position shifted from the main axis of the grindstone. The mounted workpiece is fixedly held on the surface of the worktable 2. There are no particular limitations on the fixed gripping of the workpiece, for example, various means such as adhesion with wax, suction by a template method, suction by vacuum, and the like, but there is no particular limitation. In consideration of easiness, furthermore, application of an automatic desorption method by a robot, suction by vacuum is preferable. The XY table 1 is as described above.
Arbitrary movement in the Y-axis direction is possible to perform operations such as attaching, detaching, and replacing the workpiece. Although there is no particular limitation on the method of enabling movement, for example, a V-shaped guide groove is provided on a metal table,
If it is a system that moves on it, it can be moved without vibration without any misalignment. Power for performing the movement may be, for example, a method using a general drive motor or may be manual. Further, in order to perform fine positioning, a device that performs a minute displacement using a PZT piezo element or the like as a driving source may be used in combination, and there is no particular limitation.

In actual processing, as described above, simultaneous processing is performed on both sides up to pre-polishing, and subsequent polishing is performed on only necessary surfaces, that is, single-sided processing is performed. The processing by the apparatus according to the present invention is performed as a whole up to the processing corresponding to polishing. However, since processing is performed on one side at a time, after processing on one side, the unprocessed Surface must be machined. More specifically, the workpiece on which one surface has been processed is turned upside down, and the unprocessed surface is turned upside down, and the surface is processed again. The method of inversion may be a manual or automatic method, and is not particularly limited. However, it is preferable that the inversion is performed by a work robot that also serves to move and transport the workpiece. Since the as-cut wafer, which is the workpiece, does not have a sufficient degree of parallelism in that state, first, in the first processing, processing is performed up to a portion corresponding to pre-polishing, and then the surface is turned upside down. In this state, the surface that becomes the reference surface for processing the workpiece is a surface that has already obtained a certain degree of flatness, straightness, and surface roughness. Is obtained. If this surface is processed to the final stage, it is possible to obtain a mirror surface wafer which is extremely excellent in shape accuracy and surface roughness.

The processing means of the apparatus according to the present invention sets the cutting amount for the cup-shaped diamond grindstone 5 to a predetermined value as described above, and then sets the number of revolutions of the grindstone to 1 to 50.
The workpiece 3 is cut while rotating around the X-axis at an arbitrary rotation speed between 00 RPM. The size of the cup-shaped diamond grindstone is performed without shifting the position of the grindstone axis and the workpiece during machining, so in order to machine the entire surface of the workpiece without unevenness,
It is preferable that the size be larger than the size of the workpiece. The workpiece 3 is fed while rotating the work table 2 installed on the XY table 1 at a constant speed. A processing liquid containing water or a surfactant is sprayed from a dedicated nozzle (not shown) on the processing surface during processing. The reason for spraying the machining fluid is to smooth the grinding action of the leading edge of the diamond abrasive grains, to prevent the machining heat from rising due to grinding, and to have some effect in preventing clogging due to machining. Have. The number of revolutions of the grindstone 5 and the feed speed of the workpiece 3 must be set to optimal conditions in consideration of the cutting amount by the grindstone and the grinding force.

[0021]

EXAMPLES Examples of the present invention will now be described specifically with reference to Examples, but the present invention is not limited thereto.
In this embodiment, the workpiece is machined by using the apparatus shown in FIG. 1, and the number of grinding wheels for machining is changed. In addition to the silicon wafer, a flat plate made of optical glass and high ceramics was selected as the workpiece.

Example 1 A flat plate of high ceramics was selected as a workpiece, and processing was performed using the apparatus of the present invention. The grindstone used was a resin-bonded cup-shaped grindstone having an abrasive grain size of # 4000. Water was used as the working fluid. First, roughing was performed by setting the processing pressure to 100 gf / cm ² by controlling with a servomotor and setting the rotation speed of the grindstone to 800 RPM. After that, the control of the processing was switched to the giant magnetostrictive actuator, and the finishing was performed with the cut depth being 100 nm. The processing pressure at this time was approximately 10 gf / cm ² . The surface roughness of the obtained processed surface is Ra = 8 nm, Ry = 5
0 nm, and no defects such as linear marks and pits were observed.

Example 2 A silicon wafer was selected as a workpiece, and processing was performed using the apparatus of the present invention. The grindstone used was a metal-bonded cup-shaped grindstone having an abrasive size of # 6000. Water was used as the working fluid. First, the processing pressure was set to 200 gf / cm ^{2 by} control with a servomotor, the rotation speed of the grindstone was fixed to 2600 RPM, and the processing was performed while continuously reducing the pressure continuously from 10 gf / cm ² to 10 gf / cm ² . . After that, the control of the grinding stone processing was switched to the giant magnetostrictive actuator, and the finishing processing was performed with the cutting depth set to 100 nm. The processing pressure at this time is approximately 10 gf
/ Cm ² . The surface roughness of the obtained processed surface is Ra =
5.4 nm, Ry = 23 nm, a good mirror surface was obtained, and no defects such as linear marks and pits were found on the processed surface. Further, although the work-affected layer was checked, almost no work-affected layer was observed, and the presence of a partially deep work-affected layer due to the influence of the fixed abrasive was not observed.

Example 3 A flat plate of optical glass was selected as a workpiece, and processing was performed using the apparatus of the present invention. The grindstone used was a resin-bonded cup-shaped grindstone having a grain size of 12000. Water was used as the working fluid. First, the pressure of the grindstone spindle was adjusted to 100 gf / cm ² by servo motor control.
And the roughing was performed with the grindstone rotation speed set to 1500 RPM. After that, the control of the grindstone spindle was switched to the giant magnetostrictive actuator, and the finishing was performed with the depth of cut set to 100 nm. The processing pressure at this time is approximately 10 gf / cm ²
Met. The surface roughness of the obtained processed surface is Ra = 0.15 n
m, Ry = 2.51 nm, and no defects such as linear marks and pits were observed.

[0025]

As is clear from the above embodiment,
By using the precision plane processing device according to the present invention,
Conventionally, an ultra-precision machined surface was obtained by stepwise machining in several processes, but it was confirmed that a single machine can consistently and efficiently perform from rough machining to the final ultra-precision mirror surface machining did it. As a result, not only the process can be omitted, but also energy can be saved. In the case of a silicon wafer, the etching process using a chemical solution, which is also a factor of environmental pollution, can be omitted, and the effect is greatly increased.
In the future, it has become possible to obtain an ultra-precision surface that could not be reached by the conventional method.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a precision planar processing device according to the present invention.

FIG. 2 is a plan view of the precision planar processing device according to the present invention.

FIG. 3 is a sectional view of a giant magnetostrictive actuator used in the present invention.

[Explanation of symbols]

1. 1. XY table Work table 3. Silicon wafer 4. Wheel mounting base 5. Whetstone 6. Wheel axis 7. 7. Spindle head Servo motor device 9. Hybrid actuator 10. Rod 11. Coil 12. Output terminal
13. Spring 14. Permanent magnet 15. Cooling jacket 16.
Output shaft 17. Power input terminal 20. Temperature control device 21.
Probe 22. Control panel 23. Device dedicated computer 24. Air compressor 25. Dryer 26. Processing fluid circulation device 27. Active giant magnetostrictive actuator 28. Air static pressure guide groove

[Procedure amendment]

[Submission date] October 18, 1999 (1999.10.
18)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

2. The giant magnetostrictive material used for the giant magnetostrictive actuator is terbium and dysprosium, iron, cobalt,
At least one consists of Claim first Kouki placement of precision surface working machine which is a single crystal or polycrystalline alloys of the iron group element made of nickel.

3. A grinding stone is precision surface working machine according to No. 3000 or the first claims to paragraph 2, wherein the finer diamond fine it is cup-shaped grindstone and abrasives.

4. A binder of the cup-shaped grindstone in which diamond fine powder was abrasive grain, precision surface working machine according to paragraph 1 to 3 claims, characterized in that a resin or a metal.

5. The method according to claim 1 , wherein an ultrafine diamond powder having an average particle diameter of 0.1 μm or finer is mixed in a binder of a cup-shaped grindstone using diamond fine powder as abrasive grains. Item 5. A precision plane processing machine according to Item 4 .

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a grinding wheel, a grinding wheel mounting device for mounting and rotating the grinding wheel,
A grindstone shaft that supports the mounting device and a probe (detector)
And a work table for gripping the workpiece and XY supporting the work table
A precision plane processing machine comprising a table, wherein pressure control is 10 gf / cm for operation of the precision plane processing machine.
Servo motor and a piezoelectric actuator in ^two or more ranges
10 gf / cm ² or less and 0.01
In the range up to gf / cm ² ,
This is achieved by a precision plane processing machine characterized by being performed by a giant magnetostrictive actuator provided. Further, in the above-mentioned precision plane processing machine, it is assumed that the grinding wheel uses a diamond cup type grinding wheel having an abrasive grain size smaller than # 3000.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The external appearance of a precision flattening machine according to the present invention is as shown in the sectional view of FIG. 1 and the plan view of FIG. 1 and 2, reference numeral 1 denotes an XY table. Reference numeral 2 denotes a work table mounted on an XY table, which is rotatable in forward and reverse directions around an X axis. A silicon wafer as a workpiece 3 is mounted and fixed on a work table 2. A cup-shaped diamond wheel 5 is mounted on the surface of the disk-shaped wheel mounting device 4. The diamond grindstone 5 can rotate around the X-axis at any speed from low speed to high speed in any direction in the normal or reverse direction according to the movement of the mounting device 4. The mounting device 4 is supported by a grindstone shaft 6. The grindstone shaft 6 is attached to a spindle head 7, and a drive motor for rotating the grindstone 5 is installed in the spindle head 7. XY table 1 is Y
It has a structure capable of arbitrary movement in the axial direction, and is provided with a servomotor device 8 and a piezoelectric actuator that are precisely controlled by a computer . Previous
The piezoelectric actuator is a hybrid actuator 9
It is installed inside. The servo motor device 8 and the pressure
The electric actuator drives the XY table 1 in the X-axis direction to position the workpiece 3 with respect to the diamond grindstone 5 and at least 10 gf / cm ^{2 and} 1 kg.
Pressure control up to f / cm ² is performed, and control necessary for roughing with a diamond grindstone is performed. On the other hand, the giant magnetostrictive actuator contained in the hybrid actuator 9 controls the minute cut amount required for precision machining of the workpiece by the diamond grindstone, and the corresponding range is 0.01 to 10 gf /. cm ² , which allows micro-cuts in the range of approximately 1 nm to 10 μm. By using both of these devices together, the XY table 1 can be accurately positioned with respect to the diamond grindstone 5 with respect to the diamond grindstone 5, and the XY table 1 can be cut in the X-axis direction for performing the cutting required for grinding. The fine feed is accurately performed in the range of about 1 nm to about 100 μm to control the fine cutting amount and the processing pressure.
The precision planar processing machine of the present invention is operated by rotating the grindstone and driving the device for positioning and pressure control of the workpiece.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

The giant magnetostrictive actuator referred to in the present invention is:
A giant magnetostrictive material, which is a polycrystalline or single crystal alloy with a specific ratio of a specific rare earth element and an iron group element consisting of nickel, cobalt, and iron, and undergoes a strong dimensional change when a magnetic field is applied, is used as an actuator. Things. FIG.
FIG. 3 is an explanatory sectional view of a giant magnetostrictive actuator used in the present invention. A rod 10 made of a giant magnetostrictive material is placed at the center, and its periphery is surrounded by a driving coil 11. One end of the rod 10 is fixed, and the other end is free and abuts on the output terminal 12. The output terminal 12 is urged by a spring 13 and can freely follow the displacement of the rod 10. 14 is a permanent magnet. Coil 1
A cooling water jacket 15 is disposed around the circumference 1. A magnetic field is generated by passing an electric current through the driving coil, and the giant magnetostrictive material rod 10 is deformed by the Joule effect, which is transmitted to the output terminal 12 and acts as an actuator. The cooling water jacket 15 is arranged to minimize the dimensional change due to temperature. The control range of the main shaft 6 by this giant magnetostrictive actuator is 10 gf
/ Cm ² as an upper limit, a pressure range up to 0.01 gf / cm ² , and a cut amount in a range of 1 to 100 nm, that is, a region where low pressure and extremely small displacement feed are required with high precision, specifically Is a processing area corresponding to a conventional polishing step. Tip of hybrid actuator 9
A probe 21 is installed in the section, and the displacement is detected here.
Sent to computer 23 and fed back and cut
Control the volume. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] January 14, 2000 (2000.1.1)
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a grinding wheel.
A stone, a whetstone mounting device for attaching and rotating the whetstone,
A grindstone shaft that supports the mounting device and a probe (detector)
And a work table for gripping the workpiece and XY supporting the work table
A precision plane processing machine comprising a table,
Pressure control is 10 gf / cm for the operation of surface processing machine
^TwoIn the above range, the servo motor and piezoelectric actuator
10gf / cm ^TwoLess than 0.01
gf / cm^TwoIn the range up toJacket for cooling water
GThis is performed by a giant magnetostrictive actuator equipped with
This is achieved by a precision plane processing machine characterized by the following. Ma
In the above-mentioned precision surface processing machine, the grinding wheel is
Diamond cup type with finer grain size than # 3000
A grindstone shall be used.

Claims (6)

[Claims] A grinding wheel, a grinding wheel mounting device for mounting and rotating the grinding wheel, a grinding wheel shaft for supporting the mounting device, a work table for gripping a workpiece, and an XY supporting the workpiece.
A precision plane processing machine comprising a table, wherein pressure control is performed by a combination of a servomotor device and a giant magnetostrictive actuator when the precision plane processing machine is operated. 2. The pressure control is performed by a servomotor and a piezoelectric actuator device in a range of 10 gf / cm ² or more, and by a giant magnetostrictive actuator in a range of 10 gf / cm ^{2 to} 0.1 gf / cm ^2. The precision planar processing machine according to claim 1, wherein: 3. The giant magnetostrictive material used for the giant magnetostrictive actuator is terbium and dysprosium, iron, cobalt,
3. The precision plane processing machine according to claim 1, wherein the machine is a single crystal or a polycrystal of an alloy made of at least one of iron group elements made of nickel. 4. The precision surface processing machine according to claim 1, wherein the grinding wheel is a cup-shaped wheel using diamond fine powder of # 3000 or finer as abrasive grains. 5. The precision plane processing machine according to claim 1, wherein the binder of the cup-shaped grindstone using diamond fine powder as abrasive grains is resin or metal. 6. An ultrafine diamond powder having an average particle diameter of 0.1 μm or finer is mixed in a binder of a cup-shaped grindstone using diamond fine powder as abrasive grains. Item 6. The precision plane processing machine according to Item 5.