JPH11151645A - Polishing method for substrate for disk and polishing device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing method for a substrate for disk and a polishing device thereof which can smoothly and securely polish both faces of a substrate, for disk, do not affect texturing treatment which is a post-process adversely, and perform texturing treatment simultaneously depending on conditions. SOLUTION: A central part of a substrate for disk W is nipped between a pair of grip members 110 and 210 by bringing these grip members 110, 210 near each other to grip the central part of the substrate for disk W securely by both grip members 110, 210. On the other hand, a pair of polishing bodies 160, 260 arranged on the outside of the grip members 110, 210 are brought near each other, and each polishing body 160, 260 is rotated to polish both faces of the substrate for disk W nipped between both polishing bodies 160 and 260 smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method for polishing both sides of a disk substrate used in a magnetic disk drive and a polishing apparatus therefor.

[0002]

2. Description of the Related Art Generally, a magnetic disk substrate of this type is formed by grinding a metal substrate such as aluminum with a grinder, plating the metal substrate with nickel-phosphorus, and then coating both surfaces of the metal substrate. The surface is polished by a polisher and mirror-finished, and then a surface treatment for forming microscopic irregularities (streaks) is performed on the surface of the metal substrate, which is called texturing, and a magnetic material is applied to the metal substrate. Finally, information is recorded.

[0003] By the way, when both surfaces of the metal substrate are mirror-finished, a planet carrier for supporting the metal substrate is conventionally provided between a pair of upper and lower rotating disks, and these rotating disks are moved in the same direction. By rotating, the planet carrier rotates (revolves) around the rotation axis of the rotating disk along the outer periphery of the rotating disk while rotating (rotating) with respect to its center (so-called planetary motion). Thus, a polishing apparatus is used in which both surfaces of the metal substrate supported by the planetary carrier are brought into contact with the polishing surfaces of the two rotating disks and polished.

[0004]

However, in the above-mentioned conventional polishing apparatus, since the planet carrier revolves around the rotation axis of the rotary disk while rotating, the metal supported by the planet carrier is rotated. Since the substrate moves while drawing a spiral along the outer periphery of the polishing surface of the turntable, if the polishing work is not successful and the scratches due to polishing are on the surface of the metal substrate, the shape of the polishing scratches However, there is a problem that when the degree of polishing flaw is severe, information can not be recorded on the flawed part.

In view of the above problem, the present inventors have conducted intensive studies, and as a result, even if polishing scratches occur on the surface of the metal substrate, the shape of the scratch is determined with reference to the center of the metal substrate. If they are formed concentrically,
Focusing on not affecting the subsequent texturing process, a new disk substrate polishing apparatus was developed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to polish both sides of a disk substrate smoothly and reliably, which is inferior to a subsequent texturing process. An object of the present invention is to provide a method for polishing a disk substrate and a polishing apparatus therefor, which have no influence and can simultaneously perform texturing depending on conditions.

[0007]

A first aspect of the present invention is a polishing method for polishing both surfaces of a disk substrate, wherein a center portion of the disk substrate is supported and a center of rotation of a pair of polishing bodies is provided. The polishing body is rotated in a state in which the surface of the disk substrate coincides with the center of the disk substrate, and both surfaces of the disk substrate are polished. Also,
Claim 2 of the present invention is a polishing apparatus for polishing both surfaces of a disk substrate, wherein a pair of gripping members supporting a central portion of the disk substrate are allowed to approach and separate from each other with the disk substrate interposed therebetween. A pair of polishing bodies for polishing both surfaces of the disk substrate are provided outside these gripping members, and are rotatable and mutually rotatable in a state where their rotation centers are aligned with the centers of the disk substrates. It is characterized by being provided so that it can be approached and separated freely.

According to the first aspect of the present invention, the central portion of the disk substrate is supported. In general, since the central portion of the disk substrate is not used for information recording, the quality of the disk substrate is not affected by supporting and fixing the disk substrate using the central portion of the disk substrate not used for information recording. No adverse effects. On the other hand, when polishing both surfaces of the disk substrate by rotating a pair of polishing bodies, the center of rotation of each of the polishing bodies coincides with the center of the disk substrate. Even if scratches are formed, the polishing scratches are formed concentrically with respect to the center of the disk substrate. Therefore, there is no problem during the texturing process, which is a subsequent step, and in some cases, by appropriately selecting the particle size of the polishing fluid (slurry) used for polishing and the pressing force at the time of polishing, the disk Concentric streaks (polishing scratches) on both sides of the substrate with respect to the center
So that the texturing process is performed simultaneously with the polishing process. Further, in the above-described claim 2, by bringing the pair of gripping members closer to each other, the center of the disk substrate to be polished is sandwiched between these gripping members, and the disk substrate is gripped by both gripping members. Since the center part of the disk is securely gripped, by gripping the part of the disk substrate that is not used for recording information,
The soundness of the disk substrate is maintained. On the other hand, by bringing a pair of abrasives disposed outside of the gripping members close to each other and rotating the abrasives, both surfaces of the disk substrate sandwiched between the two abrasives are smoothly polished. I do. At this time, the center of rotation of each of the polishing bodies coincides with the center of the disk substrate, so that the polishing scratches on the disk substrate are formed concentrically. In some cases, texturing can be performed in the polishing step by forming concentric stripes (polishing scratches) on the disk substrate positively in some cases.

A third aspect of the present invention is characterized in that the rotating directions of the polishing bodies are set to be opposite to each other. This cancels out the rotational force applied to the disk substrate from each abrasive body, thereby reducing the load on the gripping member gripping the central portion of the disk substrate and balancing the forces applied to the disk substrate. By doing so, the disk substrate does not rotate in either direction, and both surfaces are evenly polished.

[0010] Further, a fourth aspect of the present invention is characterized in that an air chamber for pressing the polishing body against the disk substrate is provided behind the polishing body. By adjusting the pressure of the pressurized air supplied to the air chamber, the pressing force for pressing the polishing body against the disk substrate can be easily controlled. Therefore, a favorable polishing treatment can be performed on both surfaces of the magnetic disk substrate by appropriately selecting the pressing force at the time of polishing.

Furthermore, a fifth aspect of the present invention is characterized in that a fluid supply means for supplying a polishing fluid from inside the polishing body to a polishing surface is provided on the polishing body. Polishing fluid (slurry) by this fluid supply means
Is supplied to the polishing surface from the inside of the polishing body, a sufficient amount of polishing fluid is uniformly supplied to the polishing surface of the polishing body, so that both surfaces of the disk substrate are uniformly polished.

According to a sixth aspect of the present invention, in the polishing body, a support member for supporting the polishing pad is provided on a back surface of the polishing pad in contact with the disk substrate. However, the contact surface with the polishing pad is characterized in that it is inclined in a direction away from the disk substrate as going from the center to the periphery. The polishing member pressed against the disk substrate is such that the contact surface of the support member with the polishing pad is inclined in a direction away from the disk substrate as going from the center to the peripheral portion. Becomes smaller from the center to the periphery. On the other hand, the rotating abrasive body has a higher peripheral speed at the peripheral edge portion than at the central portion. Therefore, when the contact surface of the support member with the polishing pad is not inclined, it is used for a disk. Although the polishing amount of the substrate tends to increase as it goes to the peripheral portion, since the contact surface of the support member with the polishing pad is inclined, the two are offset and uniform polishing is performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described. 1 and 2 are an overall front view and an overall side view of a polishing apparatus showing an embodiment of the present invention. The polishing apparatus has a frame 1 provided with a caster 2 and a height adjuster 3 at a lower portion, This frame 1
A pair of upper and lower guide rails 4, 5
And lift tables 6 and 7 engaged with the guide rail sections 4 and 5 so as to be able to move up and down, and polishing sections 10 and 20 installed on the lift tables 6 and 7, respectively. The lifts 6 and 7 are configured to move up and down along the guide rails 4 and 5 by rotating a ball screw shaft (not shown) by an AC servomotor.

Each of the polishing units 10 and 20 has substantially the same configuration. First, the upper polishing unit 10 will be described with reference to FIG. In FIG. 3, reference numeral 100 denotes a support cylinder, and the support cylinder 100 is fixed to the lift 6 via a support member 101 and an attachment member 102 attached to the lower end thereof. The base bracket 103 and the mounting member 1
A jig cylinder 106 is installed via the flange 04 and the flange 105, and a vertical shaft 107 is attached to a piston rod of the jig cylinder 106. The vertical shaft 107 is slidably mounted in a vertical direction inside a guide cylinder 108, and the guide shaft 108 is fixed to the base bracket 103 (not shown). A cylindrical member 109 is attached to the lower end of the vertical shaft 107, and a gripping member 110 is fitted and attached to the lower end of the vertical shaft 107 and the cylindrical member 109. On the lower surface 115 of the gripping member 110, a truncated conical recess 111 is formed. Further, the lower end of the guide tube 108 is mounted inside the upper portion of the cylindrical member 109.

A first rotary cylinder 121 of a rotary assembly 120 is rotatably supported by bearing members 122 and 123 between the support cylinder 100 and the guide cylinder 108.
A lower end of the first rotary cylinder 121 is provided with a second rotary cylinder 124.
Is attached. Then, the second rotary cylinder 124
Is rotatably supported by bearing members 125 and 126 between the mounting member 102 and the guide cylinder 108, and a driven gear 127 is attached to the outer periphery of the second rotating cylinder 124. Although not shown, the driven gear 127 is connected to the rotation mechanism 8 shown in FIG.

An air chamber structure 140 is attached to the lower end of the second rotary cylinder 124. The air chamber component 140 is attached to the second rotary cylinder 124 and is rotatably supported by the guide cylinder 108 via a bearing member 141.
42, a cylindrical second component member 143 attached to the first component member 142, and the guide cylinder 108 and the cylindrical member 1 mounted inside the second component member 143.
09, a third component 144 supported rotatably and slidably in the vertical direction, a ring-shaped fourth component 145 attached to the third component 144, and second and fourth components. Diaphragm 1 attached between four components 143, 145 via attachment rings 146, 147
48, and the first, second, third, and fourth constituent members 142, 143, 144, 14
5 and an air chamber 149 inside the diaphragm 148.
Are formed. A plurality of torque transmitting balls 1 are provided on the outer peripheral surface of the third component 144 at predetermined intervals.
50 is rotatably fitted. Further, the key groove 15 is provided in the second structural body 143 corresponding to the ball 150.
1 and the ball 150 is connected to the keyway 1.
51, the third component 144
Is provided so as to be non-rotatable with respect to the second structure 143 and to be movable in the vertical direction. Further, since the ball 150 is rotatably fitted in the third component 144, the third component 144 is set to be slightly tiltable (swingable) with respect to its rotation axis. .

A support member 161 of the polishing body 160 is attached to a lower end of the third member 144 via a ring-shaped connecting member 152, and a protection ring 153 is provided on an outer peripheral portion of the connecting member 152. Installed. The cylindrical member 10 is provided inside the support member 161.
9 and a gripping member 110 are slidably provided in a vertical direction. Also, on the surface 162 of the support member 161,
As shown in FIG. 5, a polishing pad 163 made of nonwoven fabric for polishing the magnetic disk substrate W is attached to the surface of the support member 161 (the surface in contact with the polishing pad 163).
162 is formed so as to be inclined upward (away from the magnetic disk substrate W) as going from the center to the periphery.

On the outer peripheral surface of the first rotary cylinder 121, three ring-shaped grooves 128 are formed at predetermined intervals, and these grooves 128 are formed in the air formed in the support cylinder 100, respectively. Supply hole 112 for supply, supply hole 113 for slurry supply, and supply hole 11 for supply of cleaning water (pure water)
4 is communicated. Fluid passages 129 passing through the inside of the first and second rotary cylinders 121 and 124 are respectively connected to the three grooves 128, and the fluid passages 129 for slurry supply and washing water supply are A plurality of discharge ports (fluid supply) formed on the surface of the polishing pad 163 through the inside of the polishing body 160 and communicated with the third structural body 144 by piping (not shown) provided in the air chamber 149. Means 164 (see FIG. 6). Each of the discharge ports 164 has, for example, a plurality of rows (four rows in FIG. 6) so as to draw an arc from the central portion to the peripheral edge of the polishing pad 163 in a state where a predetermined interval is provided around the circumference of the polishing pad 163. Use the formed one.

On the other hand, FIG. 4 is a cross-sectional view showing the lower polishing section 20. This polishing section 20 has the same configuration as the upper polishing section 10 and will be described in a simplified manner. A support cylinder 200 is attached to the lift 7 via an attachment member 202 and a support member 201.
, A jig cylinder 206 is attached via a base bracket 203, a mounting member 204 and a flange 205. The vertical rod 207, the cylindrical member 209, and the gripping member 210 are attached to the piston rod of the jig cylinder 206.
A guide tube 208 fixed to the base bracket 203 is mounted outside the vertical shaft 207. On the upper surface 215 of the gripping member 210,
A truncated cone-shaped convex portion 211 is formed corresponding to the truncated cone-shaped concave portion 111 formed on the lower surface 115 of the gripping member 110, and the concave portion 111 and the convex portion 211 are fitted to each other to form the gripping member. Lower surface 115 of 110 and gripping member 2
The central portion of the magnetic disk substrate W is sandwiched and fixed between the upper surfaces 215 of the magnetic disk 10.

A first rotary cylinder 221 of the rotary assembly 220 is rotatably supported by bearing members 222 and 223 between the support cylinder 200 and the guide cylinder 208.
An upper end of the first rotary cylinder 221 has a second rotary cylinder 224
Are mounted between the mounting member 202 and the guide tube 208 while being rotatably supported by bearing members 225 and 226. A driven gear 227 is attached to the outer peripheral portion of the second rotary cylinder 224, and is not shown.
Are connected to a rotation mechanism 9 shown in FIG.

The air chamber structure 240 attached to the upper end of the second rotary cylinder 224 is
24, and is rotatably supported by the guide cylinder 208 via a bearing member 241.
The constituent member 242, a cylindrical second constituent member 243 attached to the first constituent member 242, and mounted inside the second constituent member 243 and rotatable around the guide tube 208 and the cylindrical member 209. And a ring-shaped fourth component 24 attached to the third component 244.
5 and a diaphragm 248 attached between the second and fourth component members 243 and 245 via attachment rings 246 and 247 as main components, and the first, second, third, and Fourth component members 242, 243, 2
An air chamber 249 is formed inside 44, 245 and the diaphragm 248. A plurality of torque transmitting balls 250 are rotatably fitted on the outer peripheral surface of the third component 244 at predetermined intervals. Also,
A key groove 251 is formed in the second component 243 in correspondence with the ball 250. When the ball 250 fits into the key groove 251, the third component 244 becomes the second component 243. It is provided so as not to rotate with respect to the body 243 and to be movable in the vertical direction. Further, since the ball 250 is rotatably fitted into the third component 244, the third component 244 is set to be slightly tiltable (swingable) with respect to its rotation axis. .

A support member 261 of the polishing body 260 is attached to an upper end of the third member 244 via a ring-shaped connecting member 252, and a protection ring 253 is provided on an outer peripheral portion of the connecting member 252. Installed. The protection ring 253 faces the protection ring 253.
A drain receiver 254 is provided so as to be able to ascend and descend so as to cover the lower portion of the drain. The drain receiver 254 is configured to be vertically movable by a jig cylinder (not shown). Further, inside the support member 261, the tubular member 209 and the holding member 210 are provided so as to be slidable in the vertical direction. Further, a polishing pad 263 made of nonwoven fabric for polishing the magnetic disk substrate W is attached to the surface 262 of the support member 261 as shown in FIG.
The contact surface 262 is formed to be inclined upward (away from the magnetic disk substrate W) as it goes from the center to the periphery. The respective surfaces (contact surfaces with the magnetic disk substrate W) of the polishing pads 163 and 263 are opposed to each other in parallel with each other. The centers of rotation of the polishing bodies 160 and 260 correspond to the centers of the gripping members 110 and 210 (the vertical shaft 10).
7, 207).

The three ring-shaped grooves 228 formed at predetermined intervals on the outer peripheral surface of the first rotary cylinder 221 are provided with air supply holes 212 formed in the support cylinder 200 and a slurry, respectively. A supply hole 213 for supply and a supply hole 214 for supply of cleaning water (pure water) are communicated. And
The first and second rotary cylinders 22 are provided in the three grooves 228.
Fluid passages 229 passing through the insides of the first and second fluid passages 229 and 224 are respectively connected to each other. 244 side, and further communicates with a plurality of discharge ports (fluid supply means) 264 (see FIG. 6) formed on the surface of the polishing pad 263 through the inside of the polishing body 260.

Next, a description will be given of a case where a double-sided polishing of a hollow disk-shaped (doughnut-shaped) magnetic disk substrate W is performed by using the polishing apparatus having the above-described configuration. First,
In a state where a pair of upper and lower polishing units 10 and 20 are opened, the center hole of the magnetic disk substrate W is fitted into the convex portion 211 of the lower gripping member 210 so that the magnetic disk substrate W is Polishing pad 26 of polishing body 260
Place on 3 At this time, the protrusion 2 of the gripping member 210
11 is formed in a truncated conical shape (tapered shape), it is easy to insert the convex portion 211 into the center hole of the magnetic disk substrate W. Therefore, the magnetic disk substrate W It can be reliably mounted at a position (a position where the center of the magnetic disk substrate W coincides with the rotation center of the polishing pad 263). Then, by moving each of the elevating tables 6 and 7 in the vertical direction along each of the guide rails 4 and 5, the distance between the polishing units 10 and 20 is reduced.

Next, the jig cylinders 106, 20
6, the upper and lower shafts 107 and 207, and the cylindrical member 10
9, 209 and the gripping members 110, 210 are lowered or raised in a direction approaching each other along the two guide cylinders 108, 208, and the respective air chambers 149, 24
9, pressurized air is supplied from a pressurized air supply source through supply holes 112 and 212 and fluid passages 129 and 229,
Each third component 144, 244, connecting member 152, 25
2. The polishing bodies 160 and 260 are moved up and down in a direction approaching each other. Thereby, the concave portion 111 of the gripping member 110 is formed.
And the convex portion 211 of the gripping member 210 are fitted to each other, and the central portions of both sides of the magnetic disk substrate W are sandwiched between the lower surface 115 of the gripping member 110 and the upper surface 215 of the gripping member 210, respectively, and are securely fixed. Together with each polishing body 16
Both surfaces except the central portion of the magnetic disk substrate W are sandwiched between the polishing pads 163 and 263 of the magnetic disk 0 and 260. In this case, when the two gripping members 110 and 210 approach each other and the truncated cone-shaped concave portion 111 and the convex portion 211 are fitted with each other, for example, there is a slight shift between the central axes of the two gripping members 110 and 210. Even if the concave portion 1 of the gripping member 110
When the inclined surface 11 and the inclined surface of the convex portion 211 of the gripping member 210 come into contact with each other, the displacement between the two central axes can be corrected, and the central axes can be matched.

When the magnetic disk substrate W is gripped by sandwiching the central portion of the magnetic disk substrate W between the two gripping members 110 and 210, a portion of the magnetic disk substrate W that is not used for information recording is gripped. The magnetic disk substrate W can be reliably supported and fixed by the holding members 110 and 210 while maintaining the soundness of the magnetic disk substrate W without affecting the quality of the magnetic disk substrate W.

Subsequently, each of the rotation mechanisms 8 and 9 is driven,
Each rotating assembly 12 is driven via each driven gear 127, 227.
0 and 220 are rotated in opposite directions, the second rotating cylinders 124 and 224 and the air chamber components 140 and 24 are rotated.
0, polishing bodies 160, 2 via connecting members 152, 252
60 rotate in opposite directions to each other,
By supplying slurry for polishing through supply holes 113 and 213 formed in the polishing bodies 0 and 200, the polishing body 16 is supplied.
0, 260 polishing pads 163, 263, discharge ports 16
Slurry is supplied to the surface of the magnetic disk substrate W from 4, 264. As a result, the polishing pads 163 and 263 of the polishing bodies 160 and 260 rotate in directions opposite to each other, and the magnetic disk substrate W and the polishing pads 163 and 263 rotate.
The two sides of the magnetic disk substrate W are polished smoothly together with the polishing slurry supplied between the two.

At this time, since the polishing bodies 160 and 260 rotate in directions opposite to each other, each polishing pad 16
3 and 263, the forces applied to the magnetic disk substrate W cancel each other, so that the magnetic disk substrate W
No excessive load is applied to the gripping members 110 and 210 gripping the central portion of the magnetic disk, the load on the gripping members 110 and 210 can be reduced, and the forces applied to the magnetic disk substrate W are balanced. Thereby, the magnetic disk substrate W does not rotate in either direction, and both surfaces of the magnetic disk substrate W are polished evenly. In addition, since the rotation centers of the polishing bodies 160 and 260 coincide with the center of the magnetic disk substrate W, even if the surface of the polished magnetic disk substrate W has polishing scratches, the polishing scratches may occur. Are formed concentrically with respect to the center of the magnetic disk substrate W. Therefore, there is no problem during the texturing process, which is a subsequent process, and in some cases, the pressure of the pressurized air supplied to the air chambers 149 and 249 during polishing is adjusted to adjust the polishing body 16 during polishing.
By adjusting the pressing force by the pressures 0 and 260 and by appropriately selecting the particle size of the slurry to be supplied from the discharge ports 164 and 264 of the polishing pads 163 and 263, the center of the magnetic disk substrate W can be positively applied to both sides. The texturing process may be performed at the same time as the polishing step so that concentric streaks are formed with reference to.

Further, the surfaces (contact surfaces with the polishing pads 163 and 263) 162 of the support members 161 and 261 are described.
262 are formed so as to be inclined in a direction away from the magnetic disk substrate W as going from the center to the peripheral edge thereof, so that the polishing bodies 16 on both surfaces of the magnetic disk substrate W are formed.
The pressing force of 0 and 260 becomes smaller as going from the center to the periphery. On the other hand, since the peripheral speed of each of the polishing bodies 160 and 260 is higher at the peripheral portion than at the central portion, the polishing pads 163 and 26 of the support members 161 and 261 are provided.
In the case where the contact surfaces 162 and 262 with the third member 3 are not inclined, the polishing amount of the magnetic disk substrate W tends to increase toward the peripheral portion.
Since the contact surfaces 162 and 262 with the polishing pads 163 and 263 are inclined, the two are offset and uniform polishing is performed over the entire area of both surfaces of the magnetic disk substrate W.
The slurry used for the above-mentioned polishing treatment is passed through the support member 261 of the lower polishing body 260, the polishing pad 263, the connecting member 252, and the protection ring 253, and the drainage catcher 25 previously set at the upper limit position by the jig cylinder.
4 smoothly accommodated. In this case, the support member 26
1, since the contact surface 262 with the polishing pad 263 is inclined downward from the center to the peripheral edge thereof, the used slurry easily flows down along this inclination to smoothly drain. Collected in 254. At the same time, with the rotation of each of the polishing bodies 160 and 260, these polishing bodies 1
Slurry that scatters outward from 60 and 260 is blocked in the protection ring 153 or the drainage receiver 254 and does not jump out, and is reliably contained in the drainage receiver 254.

Further, the third components 144, 2
Ball 1 for torque transmission rotatably fitted in 44
50 and 250 are engaged with the key grooves 151 and 251 formed on the second component members 143 and 243 along the rotation axis thereof, so that the third component members 144 and 244 are connected to the second component members 143 and 243. 243 can be smoothly moved in the vertical direction, and the pressure of the pressurized air supplied to the air chambers 149 and 249 can be transmitted to the polishing bodies 160 and 260 with good responsiveness. The third component members 144 and 244 can be reliably swung with the rotation of the second component members 143 and 243, and the polishing body 1
The rotational force can be smoothly transmitted to 60 and 260.
In addition, since the balls 150 and 250 are rotatably fitted into the third components 144 and 244, the third components 144 and 244 can be slightly inclined with respect to the rotation axis (the neck). Swingable), so that the polishing pads 16 of the polishing bodies 160 and 260
3, 263 are inclined according to the surface shape of the magnetic disk substrate W to be polished, so that the magnetic disk substrate W can be securely brought into close contact with both surfaces of the magnetic disk substrate W. Can be polished. In this way, when the double-side polishing of the magnetic disk substrate W is completed, cleaning water (pure water) is supplied to each support cylinder 10 in place of the slurry.
The cleaning water is supplied to the surface of the magnetic disk substrate W from the discharge ports 164 and 264 of the polishing pads 163 and 263 of the polishing bodies 160 and 260 by supplying the supply water through the supply holes 114 and 214 formed in the magnetic disk substrate W. The cleaning is performed when supplied.

[0031]

As described above, according to the first aspect of the present invention,
Is a polishing method for polishing both sides of a disk substrate, while supporting a central portion of the disk substrate, and polishing the pair of polishing bodies in a state where the rotation centers of the pair of polishing bodies coincide with the center of the disk substrate. Since the body is rotated to polish both sides of the disk substrate, the quality of the disk substrate is improved by supporting and fixing the disk substrate using the center of the disk substrate not used for information recording. Can be polished while maintaining a good state without any adverse effect on the polishing. On the other hand, when polishing both surfaces of the disk substrate by rotating a pair of polishing bodies, the center of rotation of each of the polishing bodies coincides with the center of the disk substrate. Even if scratches are formed, the polishing scratches are formed concentrically with respect to the center of the disk substrate. Therefore, there is no problem during the texturing process, which is a subsequent step, and in some cases, by appropriately selecting the particle size of the polishing fluid (slurry) used for polishing and the pressing force at the time of polishing, the disk Concentric streaks (polishing scratches) can be formed on both surfaces of the substrate with respect to the center thereof, and the texturing process can be performed simultaneously with the polishing process. Further, in the above-described claim 2, by bringing the pair of gripping members closer to each other, the center of the disk substrate to be polished is sandwiched between these gripping members, and the disk substrate is gripped by both gripping members. Since the center part of the disk is securely gripped, by gripping the part of the disk substrate that is not used for recording information,
The soundness of the disk substrate can be reliably maintained. On the other hand, by bringing a pair of abrasives disposed outside of the gripping members close to each other and rotating the abrasives, both surfaces of the disk substrate sandwiched between the two abrasives are smoothly polished. can do. At this time, the center of rotation of each of the polishing bodies coincides with the center of the disk substrate, so that the polishing scratches on the disk substrate are formed concentrically. In some cases, texturing can be performed in the polishing step by forming concentric stripes (polishing scratches) on the disk substrate positively in some cases.

According to a third aspect of the present invention, since the rotational directions of the polishing bodies are set to be opposite to each other, the rotational force applied to the disk substrate from each polishing body is canceled by each other. In addition to reducing the load on the gripping member gripping the central portion of the disk substrate, the disk substrate rotates in either direction by balancing the forces applied to the disk substrate. And both sides of the disk substrate can be polished evenly.

Further, according to a fourth aspect of the present invention, since an air chamber for pressing the polishing body against the disk substrate is provided behind the polishing body, the pressurized air supplied to the air chamber is provided. By adjusting the pressure,
The pressing force for pressing the abrasive body against the disk substrate can be easily controlled. Therefore, by appropriately selecting the pressing force at the time of polishing, it is possible to perform a good polishing treatment on both surfaces of the magnetic disk substrate.

According to a fifth aspect of the present invention, a fluid supply means for supplying a polishing fluid from inside the polishing body to a polishing surface is provided on the polishing body.
By supplying the polishing fluid (slurry) from the inside of the polishing body to the polishing surface by the fluid supply means, a sufficient amount of the polishing fluid can be uniformly supplied to the polishing surface of the polishing body. It is possible to uniformly polish both surfaces of the substrate for use.

According to a sixth aspect of the present invention, in the polishing body, a support member for supporting the polishing pad is provided on a back surface of the polishing pad in contact with the disk substrate. However, since the contact surface with the polishing pad is inclined in a direction away from the disk substrate as going from the center to the peripheral portion, the inclination of the contact surface causes the disk substrate to be inclined. , The pressing force of the abrasive body pressed toward the periphery decreases from the center to the periphery. On the other hand, the rotating abrasive body has a higher peripheral speed at the peripheral edge portion than at the central portion. Therefore, when the contact surface of the support member with the polishing pad is not inclined, it is used for a disk. The polishing amount of the substrate tends to increase toward the periphery. Therefore, since the contact surface of the support member with the polishing pad is inclined, both can be offset, and uniform polishing can be smoothly performed.

[Brief description of the drawings]

FIG. 1 is an overall front view of a polishing apparatus showing an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a sectional view showing an upper polishing unit.

FIG. 4 is a sectional view showing a lower polishing portion.

FIG. 5 is a sectional view showing a main part.

FIG. 6 is an explanatory view showing a polished surface of a polished body.

FIG. 7 is a cross-sectional view showing an engagement relationship between second and third components.

[Explanation of symbols]

 W Magnetic disk substrate 110, 210 Gripping member 149, 249 Air chamber 160, 260 Polishing body 161, 261 Supporting member 162, 262 Surface (contact surface with polishing pad) 163, 263 Polishing pad 164, 264 Discharge port (fluid) Supply means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadashi Denda 520 Imazato, Susono City, Shizuoka Prefecture (72) Inventor Kenji Ochiai 1-21-241 Ogi, Adachi-ku, Tokyo

Claims (6)

[Claims] 1. A polishing method for polishing both surfaces of a disk substrate, wherein a center of the disk substrate is supported, and a center of rotation of a pair of polishing bodies coincides with a center of the disk substrate. A method for polishing a disk substrate, comprising rotating the polishing bodies to polish both surfaces of the disk substrate. 2. A polishing apparatus for polishing both surfaces of a disk substrate, wherein a pair of gripping members supporting a central portion of the disk substrate are provided so as to be able to approach and separate from each other with the disk substrate interposed therebetween. Outside these gripping members, a pair of polishing bodies for polishing both surfaces of the disk substrate, respectively, are rotatable and freely approaching and separating from each other, with their rotation centers coinciding with the centers of the disk substrates. An apparatus for polishing a disk substrate, the apparatus being provided. 3. The disk substrate polishing apparatus according to claim 2, wherein the rotation directions of the pair of polishing bodies are set to be opposite to each other. 4. The apparatus for polishing a disk substrate according to claim 2, wherein an air chamber for pressing the polishing body against the disk substrate is provided behind the polishing body. 5. The disk substrate according to claim 2, wherein a fluid supply means for supplying a polishing fluid from inside the polishing body to the polishing surface is provided on the polishing body. Polishing equipment. 6. The polishing body is provided with a support member for supporting the polishing pad on the back surface of the polishing pad in contact with the disk substrate, and the contact surface of the support member with the polishing pad is: 6. The apparatus for polishing a disk substrate according to claim 2, wherein the distance from the center to the peripheral edge is increased in a direction away from the disk substrate.