JPH10249687A - Double surface grinding-polishing machine of sheetlike workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a job for double surface grinding or polishing in a highly accurate manner even in case of such a diametrally enlarged workpiece. SOLUTION: Two ringlike grinding wheels 11 and 21 are installed on a surface to be opposed to a sheetlike work W of a pair of grinding spindles 10 and 20 being opposedly set up as holding this sheetlike work W between and two work holders 12 and 22 are installed within these grinding wheels 11 and 21. These grinding spindles 10 and 20 are positioned to the work W so as to make these grinding wheels 11 and 21 pass through a center point of the work W. As the work holders 12 and 22, porous ceramics and the like with a permeation of air and water are used, and thereby a water supply pipe supplying a working fluid and an exhaust pipe both may be installed in a turning shaft. With this constitution, since most of the surface of the work W in machining is held by the holders 12 and 22, a position of the work W is stabilized, so that highly accurate grinding or polishing is made thus achievable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for grinding or polishing both surfaces of a thin work such as a semiconductor wafer, a magnetic disk, and a glass substrate.

[0002]

2. Description of the Related Art Grinding stones such as SiC, white alundum and the like similar to the grinding of metal materials are often used for double-side grinding of a thin plate-like workpiece. For example, as shown in FIG. 1, a work 3 is sandwiched between cup grindstones 1 and 2, and both sides are polished while the work 3 is relatively rotated. Cup whetstone 1,2
When the workpiece 3 is smaller than the outer diameter of the workpiece 3, the carrier 4 holding the workpiece 3 can have sufficient mechanical strength, and the insertion / removal of the workpiece 3 via the carrier 4 is easy. is there. In addition, by making the inner diameter of the cup grindstones 1 and 2 smaller than the outer diameter, the working surface of the cup grindstones 1 and 2 can be made larger, and a large number of small workpieces 3 can be ground simultaneously.

[0003]

When grinding a hard brittle material such as a semiconductor wafer, a grinding wheel using diamond as an abrasive is used. The semiconductor wafer has a thickness of about 1 mm and has a large processing area. Therefore, in the double-side grinding in which the use of the carrier 4 thinner than the workpiece 3 is required, the holding of the workpiece 3 by the carrier 4 becomes unstable, and the posture of the workpiece 3 is easily changed during the processing. If the posture of the workpiece 3 changes during machining, a large cut is locally applied to the workpiece 3 corresponding to the change in the posture, and the desired flatness cannot be obtained. On the other hand, when a grinding wheel having a smaller inner diameter with respect to the outer diameter, that is, a large working surface is used, the number of working abrasive grains increases because the area of the workpiece 3 is large, and the grinding resistance increases. The spindle and support system of the grinding wheel will deform if they cannot withstand the increased grinding force. As a result, the abrasive grains cannot be cut into the workpiece and the workpiece cannot be ground. For this reason, for grinding hard materials such as semiconductor wafers, the use of a grinding wheel with a smaller inner diameter than the outer diameter is not suitable, and the contact area between the wafer and the grinding wheel must be reduced, This may cause the wafer being processed to become unstable.

However, with the spread of semiconductor devices and the increase in chip size, the diameter of wafers is also increasing. In accordance with this tendency, a method for efficiently polishing both surfaces of a thin plate-shaped workpiece having a large processing area as compared with the plate thickness has been desired more than ever. The same is true for double-side polishing of a magnetic disk or a glass substrate having a large diameter. In the following description and claims, grinding is used to include polishing. The present invention has been devised to meet such a demand, and a workpiece is polished while pressing the surface of the workpiece with a holding pad, regardless of the size of the processing area, and the workpiece is stably positioned. For both-side grinding or both-side polishing.

[0005]

SUMMARY OF THE INVENTION In order to achieve the object, a double-sided grinding and polishing apparatus for a thin plate-like workpiece according to the present invention comprises: a pair of grinding spindles which are opposed to each other with a thin plate-like workpiece interposed therebetween; A ring-shaped grinding wheel provided on the surface of the grinding spindle facing the workpiece, and a workpiece holder provided inside the grinding wheel, and the workpiece is placed on the workpiece so that the grinding wheel passes through the center point of the workpiece. The grinding spindle is positioned with respect to the grinding spindle. Using porous ceramics, porous plastics, porous polishing cloth, etc., with air permeability and water permeability as the workpiece holder, the water supply pipe and exhaust pipe that supply pure water and abrasive dispersion liquid are the grinding spindle. When it is installed in the internal cavity, not only can the work being processed be pressed and held, but also the work can be sucked when it is mounted or removed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A double-side grinding apparatus according to the present invention will be described with reference to the drawings, but it is needless to say that a similar configuration can be applied to a double-side polishing apparatus. As shown in FIG. 2, the double-sided grinding device includes a pair of grinding spindles 10 and 20 arranged with a workpiece W interposed therebetween. The workpiece W rotates while being supported by the drive rollers 31,31. Grinding spindle 1
Numerals 0 and 20 are arranged opposite to the workpiece W in a positional relationship where the grinding wheels 11 and 21 pass through the center point C of the workpiece W. This positional relationship is shown in FIG. 2 as a dotted line where the grinding wheel 21 contacts. A ring-shaped grinding wheel 11 is attached to the grinding spindle 10, and a workpiece holder 12 is provided inside the grinding wheel 11. Most of the surface of the workpiece W is held by the workpiece holder 12. In general, resin, vitrified,
A diamond wheel made of a metal bond or the like is used.

As the workpiece holder 12, porous ceramics, porous plastics,
A porous polishing cloth or the like can be used. In this case, as shown in FIG. 3, the grinding spindle 10 has a rotating shaft 16 for holding the holder inserted through a rotating unit 15 for holding the grinding wheel, and is connected to a working fluid supply source (not shown). Water pipe 13 and exhaust pipe 14 connected to a vacuum source (not shown)
Is arranged inside. The workpiece holder 12 is fixed to the rotating shaft 16 by, for example, a bolt and a nut, and holds the workpiece W by vacuum suction via the exhaust pipe 14. The other grinding spindle 20 has a similar structure.
The rotating shaft 16 is arranged in the axial direction so that the gap 19 between the working surface 17 of the grinding wheel 11 and the holding surface 18 of the work holder 12 can be adjusted according to the type of the work holder 12 to be used. (Not shown).

The rotation speed of the rotation shaft 15 and the rotation shaft 16 can be set independently of each other. In actual machining, the rotation shaft 16 is maintained at a rotation speed of zero, that is, a stopped state, as required. You may. In FIG. 3, the gap 19 is provided so that the holding surface 18 is retracted from the working surface 17. However, without being restricted to this, when a soft and porous polishing cloth is used as the workpiece holder 12, the gap 19 can be set so that the holding surface 18 is in an advanced state. . At the time of grinding the workpiece W, the workpiece W adsorbed on the vacuum chuck (not shown) is placed on the driving rollers 31, and one of the grinding spindles 10 is moved so that the grinding wheel 11 comes to the center point C of the workpiece W. Align to. At this time, it is preferable that the rotating shaft 16 be advanced so that the holding surface 18 projects from the working surface 17.

Next, by suction through the exhaust pipe 14,
After the workpiece W is attracted to the workpiece holder 12, the suction of the workpiece W by the vacuum chuck is released. Similarly, the holding surface of the other grinding spindle 20 is brought into contact with the other surface of the workpiece W. Then, a predetermined working fluid is simultaneously supplied from both sides of the workpiece W through the water supply pipe 13. At this time, in order to stably hold the workpiece W, it is preferable to set the pressure and the flow rate of the machining fluid to be equal on both sides of the workpiece W. As the working liquid, pure water or a polishing liquid in which abrasive grains are dispersed as necessary is used. After holding the workpiece W at a predetermined position between the grinding spindles 10 and 20, the workpiece W and the grinding spindle 1 are held.
Rotate 0,20. In this way, most of the surface of the workpiece W is held by the workpiece holders 12 and 22,
Both surfaces are ground by the grinding wheels 11 and 21. Therefore, the posture of the workpiece W is kept stable during processing, and high-precision double-side grinding can be performed. After the grinding is completed, the supply of the working fluid from the water supply pipe 13 is stopped, and the ground workpiece W is attracted to one of the grinding spindles 10 by vacuum suction through the exhaust pipe 14. Then, the other grinding spindle 20 is retracted, the workpiece W is transferred to the vacuum chuck, and transported to the next step.

[0010]

As described above, in the double-sided grinding / polishing apparatus of the present invention, the workpiece is ground while holding most of the surface of the workpiece with the workpiece holder disposed inside the ring-shaped grinding wheel. Therefore, even if the area of the workpiece is large compared to the thickness of the workpiece, the posture of the workpiece is stably maintained during the processing. Therefore, high-precision machining is possible even for a large-diameter workpiece.

[Brief description of the drawings]

FIG. 1 shows a conventional double-side polishing apparatus using a cup grinding wheel.

FIG. 2 shows a double-side polishing apparatus according to the present invention.

Fig. 3 Grinding spindle with built-in water supply pipe and exhaust pipe

[Explanation of symbols]

10, 20: grinding spindle 11, 21: grinding wheel
12, 22: Work holder 13: Water pipe 1
4: Exhaust pipe 15: Rotating unit 16: Rotating shaft
17: Working surface 18: Holding surface 19: Gap 31: Drive roller W: Workpiece C: Center point of workpiece

Claims (2)

[Claims] 1. A pair of grinding spindles arranged opposite to each other with a thin plate-shaped workpiece interposed therebetween, a ring-shaped grinding wheel provided on a surface of the grinding spindle facing the thin plate-shaped workpiece, and provided inside the grinding wheel. A double-sided grinding / polishing apparatus for a thin plate-shaped workpiece, comprising a workpiece holder and a grinding spindle positioned with respect to the workpiece so that a grinding wheel passes through a center point of the workpiece. 2. The thin plate-shaped workpiece according to claim 1, wherein a water supply pipe and an exhaust pipe for supplying a liquid are provided in an internal cavity of the grinding spindle, using a work holder having air permeability and water permeability. Double-sided grinding and polishing equipment.