JPH02269552A - Polishing method and device thereof - Google Patents

Abstract

PURPOSE:To improve polishing accuracy by linearly opposing the circumferential surface of a cylindrical rotating tool to a workpiece to be polished, and relatively moving them. CONSTITUTION:A rotating tool 11 or a polishing belt wound around the tool is linearly opposed to a wafer 14. The wafer 14 is polished in this condition by relatively moving the tool 11 and the wafer 14 at high speed and in linear movement, while being supplied with grinding liquid between opposing parts from a nozzle part 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and a polishing apparatus for polishing the surface of an object to be polished, such as a silicon wafer or an optical lens.

(Prior Art) When manufacturing a semiconductor IC board mainly made of silicon, a single crystal silicon ingot is usually sliced using a diamond blade to form a wafer, and the wafer is polished to form a wafer. The surface is finished to a mirror surface with high flatness. The wafer thus formed is
The surface can be polished to a mirror finish. The polishing of the wafer can be roughly divided into the following three steps.

First, there is a lapping process that removes warpage, blade marks, etc. from the wafer sliced by a diamond blade, and turns the wafer into a flat plate with basically uniform thickness.

Second, an etching step in which the damaged layer formed in the lapping process to a depth that reaches the wafer surface is etched away with acid or alkali.

Third, the process-affected layer due to etching (referred to as the stock layer after lapping) is removed to ensure that the pure silicon layer has a perfect mirror surface with no microscopic scratches or haze, and a flat surface necessary and sufficient for printing IC circuits. Polishing process for a beautiful finish.

In the above polishing process, a rotating flat plate type polishing device is generally used. For example, as shown in FIG. 8, the polishing device attaches a polishing pad 63 to a large rotating flat plate 61, and attaches a plurality of polishing pads 63 to the lower surface of a plurality of carrier disks 62 arranged opposite to the rotating flat plate 61. wafers 64 are mounted, and each carrier disk 62 is pressed against the polishing pad 63 by a weight 65 or other means. The wafers held on each carrier disk 62 are polished by rotating the carrier disk 62 while causing the rotating flat plate 61 to revolve while passing an abrasive liquid between the polishing pad 63 and the wafer 64. Ru.

(Problems to be Solved by the Invention) Such conventional polishing devices have many drawbacks.

First, the polishing pad 6 attached to the rotating flat plate 61
3 faces the entire polishing surface of each wafer 64 that is the object to be polished. Therefore, in order to polish each wafer 64 with high precision, the rotary flat plate 61 and the lower surface of the carrier disk 62 must be precisely flat. must be standardized. Furthermore, during polishing, the temperature of the wafer increases, which may cause distortion in the wafer. In order to correct such distortions, a complicated structure such as providing a cooling water passage inside each of the rotary flat plate 61 and carrier disk 62 to cool them is required, and furthermore, the temperature must be controlled during polishing. No. The polishing pad 63 cannot be used immediately even if it is attached to the rotating flat plate 61, and it is necessary to equalize the thickness using a diamond tool or the like, or to perform so-called co-printing in which the polishing pads 61 are polished together for a considerable period of time. be. Another problem is that mounting the wafer 64 on the carrier disk 62 requires great care.

Second, as shown in FIG. 8, when the rotating flat plate 61 revolves, the circumferential speeds of the outer and inner circumferential portions are essentially 1 m different, so the carrier disk 62 to which each wafer 64 is attached is If the wafers 64 are not rotated, the sliding momentum of each wafer 64 with respect to the polishing pad will not be equal. For this purpose, by rotating the carrier disk 62 with respect to the revolution of the rotating flat plate 51, the rotation direction and rotation speed of each wafer 64 are adjusted so that each -7=transverse momentum of the wafer 64 with respect to the polishing pad 63. Efforts are being made to achieve uniformity. However, carrier disk 62
Whether the wafers 64 attached to the carrier disk 62 are located on the outer periphery or the inner periphery of the carrier disk 62, the sliding momentum of each wafer 64 with respect to the polishing pad 63 becomes non-uniform. It is impossible to make the polysing accuracy uniform. In this way, each wafer 6
If the polishing accuracy of 4 is uneven, the polishing pad 63 will be clogged with grinding debris and worn out unevenly in the radial direction. polishing pad 6
3, radial clogging and uneven wear may occur on each wafer 64.
This causes a difference in the polishing accuracy of the wafers 64, and the difference in polishing accuracy increases as polishing is repeated, making it impossible to polish each wafer 64 with high accuracy.

Third, the conventional polishing apparatus includes 4 to 6 carrier disks 62, and each carrier disk 62 is loaded with 3 to 7 wafers 64, so that when one polishing operation is completed, at least 4 ~6 carrier discs 62 must be replaced. As described above, in the conventional polishing apparatus, the polishing operation is a continuous batch operation, and the polishing operation cannot be performed continuously, resulting in poor working efficiency. Furthermore, as described above, the polishing ability of the polishing pad 63 is uneven depending on its radial position, which is due to uneven clogging caused by the uneven relative sliding momentum between the polishing pad 63 and the wafer 64. The main cause is that it occurs uniformly. Therefore, the polishing operation is stopped before flatness defects occur on the polished wafer 64, and the polishing pad 64 attached to the rotating flat plate 61 is
A dressing operation in which the polishing layer (mainly the scraped stock after polishing) is removed by squeezing while washing the polishing material 3 must be performed every batch or every few batches.

Fourth, in the conventional polishing apparatus, a large number of wafers 64 are attached to a polishing pad 63 attached to a rotating flat plate 61.
slide at the same time, it is difficult to uniformly supply the abrasive liquid between the polishing pad 63 and each wafer 64, and it is difficult to take special consideration to the supply of the abrasive liquid. be. Normally, the abrasive liquid is caused to flow down near the center of the rotating flat plate 61, and due to the centrifugal force and the rotation of the carrier disk 62, the abrasive liquid naturally flows between the wafer 64 and the polishing pad 63. Discharge from the gap is also performed by centrifugal force. In this way, in order to interpose the abrasive liquid between the wafer 64 and the polishing pad 63 by centrifugal force, it is necessary to increase the flow rate of the abrasive liquid. The water passes over the rotating flat plate 61 without any polishing action. Even in this case, the abrasive liquid does not flow uniformly over the entire surface of the wafer 64. In order to properly supply and discharge the abrasive liquid near the center of the wafer ε4, attempts have been made to provide a groove or the like in the polishing pad 63 and allow the abrasive liquid to flow through the groove. There are disadvantages such as inhibiting the singling action, and good results are not always obtained.

Fifth, there is a problem that the polishing speed is slow. In a conventional rotating flat plate type polishing apparatus, as the size of the wafer becomes thicker, the rotating flat plate 61 also becomes larger. For example, the outer diameter of the rotating flat plate 61 is usually about 48 to 52 inches; Five to six carrier disks 62 are provided. Five to seven 6-inch wafers are mounted on each carrier disk 62. In such a large polishing device, the rotation speed must be increased. It is difficult to do this, and the rotating flat plate 61 is normally set at a low circumferential speed of about 60 to 100 m/min at the center position of the carrier disk 62, which is a fairly low speed for polishing work. The efficiency of polishing work is extremely low, and even in the rough polishing process called stock removal (polishing off the etched damaged layer), the speed is 0.5 to 1.0 μm/min, so it is usually 20 to 1.0 μm/min. It takes 30 minutes.

Sixthly, it is difficult to increase the size of the working device. As mentioned above, polishing equipment for 6-inch wafers is approaching the limits of work and maintainability, but in the near future,
In an environment where 8-inch wafers are used, increasing the size of polishing equipment becomes a serious problem. Therefore, single-wafer polishing equipment or small-wafer polishing equipment that polishes each wafer has been developed, but since both equipment rotates the wafer, they suffer from the above-mentioned problem and the second problem. The basic drawback is that the wafer is not polished radially uniformly.

For example, Japanese Patent Application Laid-Open No. 52-162467 discloses a method in which a wafer is attached to a chuck and rotated, and a polishing roll made of cloth or a band is brought into rotating contact with the wafer to perform polishing while supplying a polishing liquid to the processing surface. Disclosed. The device is applicable only to so-called final polishing, which is the final step of polishing, and
The polishing roller itself is made of cloth, a band, etc., and exhibits a so-called buff roll-like action. Furthermore, since the wafer is rotated in contact with the polishing roller, there is a problem in that, as described above, there is a difference in polishing accuracy between the inner circumference and the outer circumference of the wafer.

Japanese Patent Publication No. 61-16586, Japanese Patent Publication No. 62-1624
No. 66 discloses a polishing method using a band-shaped belt. However, in both methods, similar problems arise because the object to be polished is polished while being rotated.

The present invention solves these conventional problems,
The purpose is to polish the entire wafer with high precision, which significantly improves polishing accuracy.
Moreover, it is an object of the present invention to provide a polishing method and a polishing apparatus that significantly improve polishing work efficiency.

(Another Means to Solve the Problem) The polishing method of the present invention provides a method for polishing a workpiece to be polished.
While rotating cylindrical rotary tools that are disposed facing each other with their circumferential surfaces substantially in linear contact with each other, supplying an abrasive liquid between the opposing portion of the circumferential surface of the rotary tool and the object to be polished; The above object is achieved by linearly moving the two relative to each other in a direction forming an appropriate angle with respect to the axis of the rotary tool.

The object to be polished and the rotary tool are in a non-contact state.

The object to be polished has a flat plate shape, and the object to be polished and the rotary tool are relatively moved in a direction substantially perpendicular to the axis of the rotary tool.

A groove is formed on the outer peripheral surface of the rotary tool to facilitate the flow of the abrasive liquid.

A polishing belt is wound around the outer circumferential surface of the rotary tool over the entire circumference or a part of the circumferential direction.

The polishing bell 1- and the object to be polished are in a non-contact state.

The polishing belt is endless.

The polishing belt has an end, and is wound around a part of the rotary tool and wound up by a winding means.

The NLlta polishing belt is immersed in a cleaning liquid and cleaned during its rotation.

The polishing device of the present invention has a polishing device that provides polishing to the object to be polished.
A cylindrical rotary tool rotatably disposed facing each other with their circumferential surfaces substantially in linear contact with each other, and a means for supplying an abrasive liquid between the opposing portion of the circumferential surface of the rotary tool and an object to be polished. and a means for linearly moving the rotating tool and the object to be polished relative to each other in a direction forming an appropriate angle with respect to the axis of the rotating tool, thereby achieving the above object. Ru.

The rotating tool is in a non-contact state with the object to be polished.

The object to be polished has a flat plate shape, and the object to be polished and the rotary tool are relatively moved in a direction substantially perpendicular to the axis of the rotary tool.

A groove is formed on the outer peripheral surface of the rotary tool to facilitate the flow of the abrasive liquid.

A polishing belt is wound around the outer circumferential surface of the rotary tool over the entire circumference or a part of the circumferential direction.

The polishing belt and the object to be polished are in a non-contact state.

The polishing belt is endless.

The polishing belt has an end, and is wound around a part of the rotary tool and wound up by a winding means.

A cleaning liquid tank containing cleaning liquid for the polishing belt is disposed in an area where the polishing belt circulates.

(Example) The present invention will be described below with reference to Examples.

The polishing method of the present invention includes, for example, FIGS.
This is carried out using the polishing apparatus of the present invention shown in C).

In this device, for example, the cylindrical rotary tool 11 is a precision bearing.
6 and is arranged so as to be able to rotate with high precision. A pair of guides 12 and 12 that are integrally formed with each bearing 16 are disposed above each bearing 16 . Each guide 12 is located above each end side of the rotary tool 11, and a flat plate carrier 13 is disposed between both guides 12.
is being bridged. The flat plate carrier 13 is guided by each guide 12 and reciprocates above the rotary tool 11 in the axial direction or a direction close to the axial direction, while moving in a direction perpendicular to the axis of the rotary tool 11. Alternatively, it is moved back and forth in an appropriate oblique direction. A polished smooth wafer 14 is mounted on the lower surface of the flat carrier 13 facing the rotary tool 11. A nozzle portion 15 is provided near the upper end of the rotary tool 11 for discharging abrasive liquid upwardly from the upper end of the rotary tool 11 .

Further, below the rotary tool 11, a shaping jig 17 is disposed that contacts the circumferential surface of the rotary tool 11 and moves back and forth along its axial direction. Shape the surface so that it is parallel to its axis. With this configuration, the wafer 1 mounted on the flat carrier 13
4 is reciprocated approximately tangentially with respect to the upper end of the rotary tool 11 with an appropriate gap parallel to the axial direction. An abrasive liquid is discharged from the nozzle portion 15 toward the wafer 14 into this gap, and the abrasive liquid is interposed between the rotary tool 11 and the wafer 14 .

The rotary tool 11 is being rotated at high speed, and the wafer 14 is linearly opposed to the peripheral surface of the rotary tool 11 with an abrasive liquid interposed therebetween, and the wafer 14 is polished by the abrasive liquid interposed between the two. Ru. The abrasive liquid is discharged toward the opposite side of the nozzle portion 15 with the rotary tool 11 in between.

The rotary tool 11 is basically made of a material such as hard plastic that has high shape retention and can be easily processed with high precision. The rotary tool 11 is water-cooled from the inside as necessary.

The rotary tool 11 is drum-shaped or disk-shaped, but if necessary, the outer peripheral surface may be provided with recesses, grooves, etc. for holding the abrasive liquid or making it easier to flow.

As the abrasive liquid, generally used is an alkaline colloidal silica aqueous solution, an alkaline or acidic aqueous solution in which fine abrasive grains are suspended, or a mixture thereof with an amine added thereto. The fine abrasive grains contained in the abrasive solution mechanically polish the wafer, and the wafer is chemically polished by the acidity or alkalinity of the abrasive solution and by the amine added to the abrasive solution. Each polishing operation in the rough polishing process, intermediate polishing process, and finishing process is performed using such an abrasive liquid.

Such abrasive liquid and polishing method using it are as follows:
For example, Tokuko Showa 61. It is disclosed in Japanese Patent No.-38954.

As shown in FIG. 2, a polishing belt 18 may be wrapped around the entire outer peripheral surface of the rotary tool 1. The lower part of the circumferential region of the polishing belt 18 is located in a cleaning liquid tank 21 containing a cleaning liquid, and the polishing belt 18 is cleaned with the cleaning liquid in the cleaning liquid tank 21.

The polishing belt 18 is made of an endless seamless boring pad material capable of retaining an abrasive liquid, depending on the constituent material and conditions of use.

The polishing belt 18 is, for example, attached to the rotary tool 11 and rotated integrally with the rotary tool 11.

In this case, supplying the abrasive liquid by the nozzle part 15 between the opposing parts of the polishing belt 18 and the wafer 14 is the first step.
This is similar to the embodiment shown in the figure.

In the cleaning liquid tank 20, a scrubber roll 22 that rolls into contact with the polishing belt 18 is disposed on the side where the polishing belt 18 attached to the rotary tool 11 exits from the cleaning liquid. The scrubber roll 22 has a brush shape and removes grinding debris and the like adhering to the polishing belt 18.

Further, a regeneration roll 23 is disposed in rolling contact with the polishing belt 18 on the side of the cleaning tank 21 where the rotary tool 11 enters the cleaning liquid. The regeneration roll 23 is made of rubber, for example, and is regenerated by coming into rolling contact with the surface of the polishing belt 18 and grinding the surface.

The polishing bell) 18 does not need to be wrapped around the entire circumference of the rotary tool 11; for example, as shown in FIG. 3, a driven roller 24 may be disposed below the rotary tool 11,
A tension roller 25 is disposed between the driven roller 24 and the rotary tool 11, and an endless polishing belt 18 is wound around the driven roller 24 and the tension roller 25. The polishing belt 18 may be wound approximately half a circumference around the surface.

In this case as well, in order to clean and regenerate the polishing belt 18, the driven roller 24 is connected to the scrubber roller 22 and the regeneration roller 2 in the same way as in the embodiment shown in FIG.
3 is disposed in the cleaning liquid tank 20 in which the cleaning liquid tank 3 is disposed.

Furthermore, the polishing belt 18 need not be endless (for example, as shown in FIG. The polishing belt 18 may be wound around a part of the rotating tool 11 via rollers 32 and 33. It is wound around 36 times.

Also in this case, a cleaning liquid tank 21 is provided in the area around which the polishing belt 18 revolves. In this way, when the polishing belt 18 has an end, the polishing belt 18
can be easily moved back and forth, so it may be configured to move back and forth during polishing of the wafer 14.

Furthermore, the wafer 14 may be bored in multiple stages using a large number of rotary tools 11.

For example, as shown in FIG. 5, a large number of rotary tools 11 are arranged in parallel in the moving direction of the wafer 14, facing the area in which the wafer 13 is transported by the carrier 13, and each rotary tool 11 is arranged below between adjacent rotary tools 11. Driven rolls 41 are arranged in parallel,
The polishing belt 18 may be wound alternately around each rotary tool 11 and the driven roll 41.

Each driven roll 41 is arranged in an abrasive liquid tank 42 containing an abrasive liquid, and the polishing belt 18 passing around the circumferential surface of each driven roll 41 retains the abrasive liquid in the abrasive liquid tank 42 . In this case, the polishing belt 18 may be endless or may have ends as shown in FIG. In either case, the cleaning liquid tank 21 with the scrubber roll 22 and the regeneration roll 23 is connected to the polishing belt 18.
It should be placed in the orbiting area of .

The polishing belt 18 may be a felt-type polishing pad material formed into an endless seamless shape or a long cut-out shape, a nap-type polishing pad material formed into an endless seamless shape or a long cut-out shape, or the like. The inside or back of a pad-like structure is reinforced with a hood-like, woven fabric, or sheet-like flexible tensile material, the polishing surface is made of woven fabric, and the back of the woven fabric is covered with an elastomer of an appropriate thickness. A polishing pad material made of bonded and laminated layers formed in an endless seamless manner or in the form of long pieces, or a single or composite laminated structure of plastic or elastomer, and polishing on some side of the pad material. Polishing that has a surface with recesses arranged at an appropriate density to hold the abrasive liquid, or grooves etc. that are embossed or engraved to improve the flow of the abrasive liquid. A pad material formed in an endless seamless manner or in a long cut-out shape is used.

In each of the embodiments of the present invention described above, the shape of the wafer is shown as a rectangular shape. Even if the wafer is a shaped wafer, the present invention is not applied in any way. The object to be polished is not limited to silicon wafers, but also semiconductor materials such as gallium arsenide, LiNbO3, LiTaO3, sapphire, metal materials such as A1, stainless steel, etc.
It may also be an optical material such as glass or SiC.

Further, in each embodiment, a case has been described in which the rotary tool 11 is below and the wafer 14 passes above the rotary tool 11, but the present invention is not limited to such a case. Even if the top and bottom of each embodiment are reversed, or the wafer is fed from the bottom to the top or from the top to the bottom, the axis of the rotary tool is not horizontal but vertical, and the wafer is fed vertically. It may also be sent laterally.

Rotary tools are manufactured from hard plastic, Duracon, fluororesin, celluloid, etc. The rotary tool 11 is not limited to a cylindrical shape having a constant diameter, but may be, for example, a drum shape in which the outer diameter of the central portion is larger than that of each end. When the rotary tool has such a shape, it is suitable for polishing, for example, an optical material whose surface is concave.

The object to be polished, such as a wafer, may be moved reciprocally with respect to the rotary tool, or may be moved only in one direction. The structure may be such that the rotary tool is moved.

As described in detail above, the present invention allows the rotary tool or the polishing belt wound around the rotating tool to move linearly at a relatively high speed while facing the wafer in a linear manner, and mechanically between the opposing parts. In addition, since the object to be polished is polished by intervening and acting on an abrasive liquid having chemical polishing power, the polishing pad material and the object to be polished are brought into approximate contact with each other as in the past, and the gap between the two is removed. In addition, the rotary tool rotates at high speed without directly contacting the object to be polished, thereby reducing the viscous fluid friction of the abrasive liquid in contact with the surface of the object to be polished. It may also be an embodiment in which polishing is performed.

Next, an experiment was conducted using the method of the present invention, which will be described in detail.

(Experiment example 1) The wafer was polished using the apparatus shown in FIG.

This device supports a rotary tool (diameter 150 mm, surface length 180+mn) made of gunmetal with hard chrome plating on an air bearing. The rotary tool has an outer peripheral straight line 1111j0.
The deflection around the outer periphery of 048 m1 was 02 μm. Add to this a felt type polishing pad material with a thickness of 0.8non (
Manufactured by Rozor Nitta Co., Ltd., product name rSUBA-60
A polishing belt with a core diameter of 1.50 m+n,
It was wound on a pair of take-up reels each having a flange diameter of 380 mm, and also wound around a rotary tool. This polishing belt was repeatedly run on a take-up reel in alternate directions at a speed of 150 m/min.

In order to use this device for the rough polishing (stock removal) process of silicon wafers, a 6-inch wafer was mounted on a carrier, and the polishing liquid was an aqueous solution of 2% colloidal silica sol component with ethanolamine added.
While supplying the carrier uniformly across the width at a flow rate of 50 cc/min, the carrier was fed with a stroke of 20 + nm,
Reciprocation was performed at 40 cycles/min. For each run of the polishing belt, the polishing belt was intermittently fed up to 30 times from one direction to the other while the belt was running, and stock removal of one wafer was performed in about 17 minutes.

The obtained wafer had a surface roughness Rmax of 20 to 30 people, and the removal of the wafer was 15 μm, and the flatness after polishing was TT.
V (Total Th1ckness Variat
ion) 0.8 μm, and was able to achieve a finish equivalent to or better than the conventional rough polishing process with approximately twice the efficiency.

(Experimental Example 2) As in Experimental Example 1, a rotary cylinder made of gun metal plated with hard chrome (diameter 15 mm, surface length 180 mm) was supported by an air bearing, and the outer circumferential straightness was 0.04 μm and the outer circumferential deflection was 0.
．． 2 μm was obtained. The back side of thin nylon plain woven cloth is coated with soft plastic (polyurethane), and the thickness is 0.3 mm and the width is 175 mm.
A long uncut polishing belt with a length of 130 mm and a length of 130 mm was wound around a pair of take-up reels with a core diameter of 150 mm and a flange diameter of 380 mm, and was also wound around a rotary tool. This polishing belt is 100m7
It was run repeatedly in alternating directions between the take-up reels at a speed of 1 minute.

In order to use this device for the intermediate polishing process of silicon wafers that have undergone the stock removal polishing process according to Experimental Example 1, the polishing belt is intermittently fed up to 40 mm each time the belt runs, and the intermediate polishing process of the wafer is completed in about 3 minutes. I did it. The obtained wafer has a machining allowance of 0.8 μm and an obtained surface roughness of Rmax.
# Reached 10-20 people.

(Experiment example 3) The wafer was polished using the apparatus shown in FIG.

The rotary tool of the device was made of hard chrome-plated gunmetal (diameter: 150 mm, axial length: 180+n+n), as in Experimental Example 1, and was supported by an air shaft.

The outer circumference straightness of the rotary tool is 0,048 m5 and the outer circumference deflection is 0.
, 2 μm. A roller with the same diameter as the rotary tool is installed in parallel on the opposite side with a center-to-center distance of approximately 600 strokes, a seamless endless polishing belt (described later) is wound between the two cylinders, and a tension roller is used to tension the belt without slack. I let it happen.

The polishing belt is a biaxially stretched polyester film with a thickness of 180 μ'' and a width of 175 μm.
1680 mm long, seamless and endless, the surface is coated with polyurethane to a thickness of 60 μm, and grooves with a width of In+m and a depth of 20 μm are formed at a pitch of 3 mm.
, which was embossed at an oblique angle of 30° was used.

This device was run at a belt speed of 150 m/7 min, and while supplying a colloidal silica aqueous solution diluted to a silica sol concentration of 1.5%, the finishing polynosing process of the silicon wafer sheet that had undergone the intermediate volumizing process in Experimental Example 2 was carried out. used for.

The wafers were transferred from one side to the other at 50 mm/min with a 20 mm stroke and a reciprocating motion at 40 cycles/min. In this case, the gap between the polishing belt and Uninow was adjusted to an average of 1 μm±0.41 tm. the result,
The final polishing step was carried out in about 3 minutes, and the obtained result was an average removal of 0.2 μm, and the microslatch, haze, etc. remaining after the intermediate polishing step were completely removed, resulting in a mirror-like flat surface.

(Experimental Example 4) Polishing was performed using the apparatus shown in FIG. The cylindrical rotary tool was made of hard chrome-plated gunmetal, and a hard PVC outer cylinder was press-fitted to the outer periphery to have an outer diameter of 150 mm and an axial length of 180 mm. Both axes of the rotary tool are supported by pneumatic bearings and a motor rotor (not shown) is attached to provide direct electric drive, and the inverter current is used to drive the tool at 600r, p.
When the rotational speed was set to approximately 283 m/min and the circumferential speed was approximately 283 m/min, the fluctuation in the rotation accuracy of the outer peripheral surface was 0.3 μm or less. The outer circumferential surface has a depth of 0.3 mm.

A ceramic guideway is provided on the structural base that is integral with the bearing shaft, in which a groove with a width of 3 mm is installed with a helix angle of 30' and a pitch of 6. A 6-inch wafer made of
Send from one side to the other at a speed of m, during which a round trip fi25
Side-to-side movements were made at a base of 120 mm/min.

An aqueous solution of colloidal silica was diluted to a silica sol concentration of 1.5% over the entire width of the rotary tool at an average flow rate of 100 cc/min between the linearly opposing wafer and the rotary tool, and the temperature was 2.
The temperature was adjusted to 5°C and supplied.

This apparatus was used for the finishing process of silicon wafer 1. The gap between the wafer and the outer circumference of the rotary tool was adjusted to an average of 0.4 μm, but the surface roughness was Rmaχ≠1 after the intermediate polishing process before the finishing process.
0 wafers Rmax < 5 A after polishing,
Therefore, the average removal amount for this polish is 0.25μ
m, and a perfect jet black mirror surface was obtained without microscratches, haze, etc.

This result was about 10 times faster than the conventional final polishing process.

(Experimental Example 5) When polishing was carried out in the same manner as in Experimental Example 4 while changing the gap between the two-turn tool and the wafer, the results shown in the graph shown in FIG. 7 were obtained. Gap between rotating tool and wafer is 0μm
In this case, a machining speed of 100 μm/hour results in a surface roughness of about 10 people, and if the spacing is 5 μm, a machining speed of 50 μm/hour results in a surface roughness of 5 to 4 people, and further, with a spacing of 10 μm, the surface roughness is 30 μm/hour The surface roughness of the four people decreased at the machining speed of Furthermore, the spacing of 15-30 μm is 15-5 μm.
At a machining speed of m/hour, the surface roughness was reduced to 3 Å or less, which can be called the ultimate.

(Effects of the Invention) As described above, the polishing method of the present invention makes the circumferential surface of the cylindrical rotary tool and the object to be polished linearly opposed to each other, and moves them linearly relative to each other. Unlike the rotating disk polishing method, there is no risk of uneven relative sliding between the object to be polished and the polishing pad, etc.
Poly, sing accuracy is significantly improved. Furthermore, the apparatus used to carry out the method can be miniaturized, and it is also easy to apply water cooling from the inside, so that an apparatus with high polishing accuracy can be easily realized.

For example, if the object to be polished is a silicon wafer for IC manufacturing, it is extremely easy to obtain the required TTV of 1 μm or less.

Furthermore, when using a polishing belt, it is possible to discharge the polishing layer, regenerate the polishing surface, clean it, supply abrasive liquid, etc. outside the polishing work area of the polishing belt. There is no need to interrupt polishing work.

Since the speed of the polishing belt can be easily changed, it is easy to roll the gap between the polishing belt and the object to be polished, and as a result,
An ultra-high precision polished surface can be obtained, the polishing speed can be significantly improved in the intermediate polishing step before final polishing, and the polishing work can be performed with high efficiency. Even if the diameter of the millicon wafer to be polished increases, it can be easily handled.

By mounting the wafer on a carrier and through-feeding it in one direction while giving it a small circular motion or rotating it, the wafers can be continuously polished one by one.

Furthermore, maintenance such as cleaning and regenerating the polishing cloth, which was required frequently in the past, can be performed in parallel while the polishing belt is in operation, so polishing work can be performed without interruption until the end of the polishing belt's lifespan. Can be continued.

Therefore, the polishing work can be easily performed in a continuous manner, instead of the so-called batch work in which a large number of wafers are attached to one polishing operation and the wafers are removed and removed after each polishing operation as in the past.
Polishing work can be performed highly efficiently with stable polishing finish quality.

The polishing belt can be used at much higher linear speeds than conventional rotary disk bolishers without mechanical stress. Therefore, by selecting a combination with the kinematic viscosity of the abrasive liquid, the state of contact between the polishing belt and the object to be polished can be easily controlled as contact, single contact, or non-contact (only the abrasive liquid film is in contact). I can do it.

As a result, when the polishing belt is used in the initial step of wafer polishing, polishing efficiency can be improved by using it in a contact or single contact state. Furthermore, when used in the finishing process of wafer polishing, a non-contact state can be selected, and the surface of the finished wafer can be made into a highly mirror-like flat surface without haze or crystal roughness.

[Brief explanation of drawings]

FIG. 1(a) is a plan view showing an example of an apparatus used for carrying out the method of the present invention, FIG. 1(b) is a cross-sectional view taken along the line 13-B, and FIG. 2(a) is a sectional view of another example of the apparatus used for carrying out the method of the present invention, FIG. 2(b) is a front view thereof, and 3. 6 to 6 are sectional views of other examples of the apparatus used to carry out the method of the present invention, and FIG. 7 shows the gap between the polishing belt and the wafer, the polishing speed, and the speed of the wafer in an embodiment of the method of the present invention. A graph showing the relationship with surface roughness, FIG. 8(a) is a side view of a conventional polishing apparatus, and FIG. 8(b) is a cross-sectional view taken along the line B--B. DESCRIPTION OF SYMBOLS 11... Rotating tool, 12... Guide, 13... Carrier 14... Wafer, 15... Nozzle part, 18
...polishing belt, 21...cleaning liquid tank,
22... Scrubber roll, 23... Regeneration roll. that's all

Claims (1)

[Scope of Claims] 1. While rotating a cylindrical rotary tool that is disposed facing the workpiece to be polished with the circumferential surface substantially in linear contact with the workpiece, the circumferential surface of the rotary tool is rotated. A polishing method characterized by supplying an abrasive liquid between opposing parts of the rotating tool and the object to be polished, and linearly moving the two relative to each other in a direction forming an appropriate angle with respect to the axis of the rotary tool. 2. Claim 1, wherein the object to be polished and the rotary tool are in a non-contact state.
Polishing method described in . 3. The polishing method according to claim 1, wherein the object to be polished is in the shape of a flat plate, and the object to be polished and the rotary tool are moved relative to each other in a direction substantially perpendicular to the axis of the rotary tool. 4. The polishing method according to claim 3, wherein a groove is formed on the outer circumferential surface of the rotary tool to facilitate passage of the abrasive liquid. 5. The polishing method according to claim 1 or 2, wherein a polishing belt is wound around the entire circumference or a part of the circumference around the outer peripheral surface of the rotary tool. 6. The polishing method according to claim 5, wherein the polishing belt and the object to be polished are in a non-contact state. 7. The polishing method according to claim 5, wherein the polishing belt is endless. 8. The polishing method according to claim 5, wherein the polishing belt has an end, is wound around a part of a rotary tool, and is wound up by a winding means. 9. The polishing method according to claim 5, wherein the polishing belt is cleaned by being immersed in a cleaning liquid during its rotation. 10. A cylindrical rotary tool that is rotatably disposed facing the workpiece to be polished with its circumferential surface substantially in linear contact with the workpiece; Polishing comprising: means for supplying an abrasive liquid between opposing parts; and means for linearly moving the rotary tool and the object to be polished relative to each other in a direction forming an appropriate angle with respect to the axis of the rotary tool. Device. 11. The polishing apparatus according to claim 10, wherein the rotating tool is in a non-contact state with the object to be polished. 12. The polishing apparatus according to claim 10, wherein the object to be polished has a flat plate shape, and the object to be polished and the rotating tool are moved relative to each other in a direction substantially perpendicular to the axis of the rotating tool. 13. The polishing apparatus according to claim 12, wherein a groove is formed on the outer circumferential surface of the rotary tool to facilitate the flow of the abrasive liquid. 14. The polishing device according to claim 10 or 11, wherein a polishing belt is wound around the entire circumference or a part of the circumference around the outer peripheral surface of the rotary tool. 15. The polishing apparatus according to claim 14, wherein the polishing belt and the object to be polished are in a non-contact state. 16. The polishing apparatus according to claim 14, wherein the polishing belt is endless. 17. The polishing apparatus according to claim 14, wherein the polishing belt has an end, is wound around a part of a rotary tool, and is wound up by a winding means. 18. The polishing apparatus according to claim 14, wherein a cleaning liquid tank containing cleaning liquid for the polishing belt is disposed in a rotational movement area of the polishing belt.