GB2337220A

GB2337220A - Spindle assembly and cutting unit

Info

Publication number: GB2337220A
Application number: GB9910098A
Authority: GB
Inventors: Tohru Kubota
Original assignee: Disco Corp
Current assignee: Disco Corp
Priority date: 1998-05-14
Filing date: 1999-04-30
Publication date: 1999-11-17
Anticipated expiration: 2019-04-30
Also published as: GB2337220B; JPH11330009A; GB9910098D0

Abstract

Disclosed is an improved spindle assembly comprising a spindle (21) having a blade mount (24 or 29) attached to its end for mounting a cutting blade (13) thereto, and a housing (11) having the spindle air-suspended in the radial and thrust directions. The housing (11) has an anti-contamination cover (25 or 32) placed between the spindle and the spindle housing, thereby preventing debris from invading the space (27) between the spindle and the housing. Also, disclosed is a cutting unit (10 or 30) equipped with the improved spindle assembly.

Description

Spindle assgnb_ly and cuttiM unit 2337220 The present invention relates to

a cutting unit having a spindle assembly equipped therewith, and such a spindle assembly for 5 cutting workpieces such as semiconductor wafers or ceramics.

Fig. 7 shows a cutting apparatus 40 f or cutting semiconductor waf ers W. The cutting apparatus 4 0 has a semiconductor wafer W attached to its chuck table 41. Specifically the semiconductor wafer w is attached to the mount frame F of the apparatus 4 0 by means of an adhesive tape T, and the semiconductor waf er W is sucked and pulled on the chuck table 41 by applying a negative pressure to the workpiece W.

The chuck table 41 can be driven in the X-direction to put the semiconductor waf er W under the alignment means 42 of the apparatus 40, so that the alignment means 42 may detect the area to be cut or diced in the workpiece W according to the pattern-matching method. Then, the chuck table 41 is driven in the X-direction to permit the cutting unit 43 to cut the so detected area of the workpiece W.

Referring to Fig.8, the cutting unit 43 comprises a synchronous motor 46 comprising a rotor 44 and a stator 45, a spindle 21 integrally connected to the shaft of the synchronous motor 46, a spindle housing 11 bearing the spindle 21 rotatably, a blade mount 24 attached to the tip end of the spindle 21 and a cutting blade 13 attached to the blade mount 24.

The spindle 21 is supported by radial and thrust bearings 22 and 23 by directing the f low of air in the radial and thrust directions. When the rotor 44 rotates, the spindle 21 and the cutting blade 13 rotate, and when the chuck table 41 is moved in the X-direction, the cutting blade 13 is put in contact with the semiconductor waf er 1.

W to cut the same.

While cutting the workpiece W, a jet of water is directed to the place where the cutting blade 13 cuts the workpiece W, thus sputtering water and debris thereabouts. Water-and-debris mixture invades the very narrow annular space (several microns wide) 27 between the spindle 21 and the spindle housing 11 so that debris may attach to the outer surface of the spindle 21 and the inner surface of the spindle housing 11. Then, it is likely to cause so-called---scuffing- on the outer surface of the spindle 21 and on the inner surface of the spindle housing 11.

In an attempt to prevent invasion of the water-and-debris mixture into the annular space 27 the cutting unit 43 is equipped with air-seal means f or ejecting the f low of air from the annular space 27 as indicated by arrows in Fig. 8. The spindle and the spindle housing, however, cannot be completely protected against contamination.

Ref erring to Fig. 9, the cutting unit 4 7 has a blade mount 2 9 having an upright wall confronting the annular space 27. Thecuttingunit 47, however, cannot be protected against the "scuffing" by the water-and- debris mixture.

To remove the debris from the spindle 21 and the spindle housing 11 it is necessary to disassemble the spindle housing 11. Such disassembling is a time-consuming and laborious work.

There has been, therefore, an increasing demand for effectively 30 preventing invasion of water-and-debris mixture into the very small annular space between the spindle and the spindle housing.

One object of the present invention is to provide an improved spindle assembly which can effectively prevents its spindle and spindle housing from being contaminated with the water-and-debris mixture.

To attain this object a spindle assembly comprising a spindle having a blade mount attached to its end for mounting a cutting blade thereto, and a housing having the spindle air-suspended in the radial and thrust directions is improved according to the present invention in that the housing has an anti -contamination cover placed between the spindle and the spindle housing, thereby preventing debris from invading the space between the spindle and the housing.

Another object of the present invention is to provide an improved cutting unit structure which can effectively prevents its spindle and spindle housing from being contaminated with the waterand-debris mixture.

To attain this object a cutting unit comprising: at least a chuck table f or holding a workpiece; a cutter f or cutting the workpiece on the chuck table, the cutter including a spindle unit comprising a spindle having a blade mount attached to its end for mounting a cutting blade thereto, and a housing having the spindle air-suspended in the radial and thrust directions; and means for f eeding coolant water to the cutter for cooling, is improved according to the present invention in that the housing has an anti-contamination cover placed between the spindle and the spindle housing, thereby preventing debris f rom invading the space between the spindle and the housing.

The anticontamination cover may be placed between the spindle housing and the blade mount to cover the space between the spindle and the spindle housing in non-contact condition.

The anti -contamination cover may be placed to cover the blade mount 1 and the neck of the spindle exposed from the spindle housing in non- contact condition.

Other objects and advantages of the present invention will be understood from the following description of a spindle assembly and a cutting unit according to the present invention., which are shown in accompanying drawings.

Fig. 1 is an exploded, perspective view of a cutting unit according to the present invention; Fig.2 is a perspective view of cutting unit, showing how the cutting unit cuts a semiconductor wafer; Fig. 3 is a longitudinal section of a spindle assembly according to a first embodiment of the present invention; Fig.4 is a plane view of an anti-contamination cover; Fig. 5 is a longitudinal section of a spindle assembly according to a second embodiment of the present invention; Fig. 6 is a plane view of an anti-contamination cover to be used in the spindle assembly of Fig.5; Fig.7 is a perspective view of a cutting apparatus having a cutting unit equipped therewith; Fig. 8 is a longitudinal section of a conventional spindle assembly; and Fig. 9 is a longitudinal section of another conventional spindle assembly.

Fig.1 shows a cutting unit according to the present invention, which is described below as being used in place of the cutting unit 4 3 in the cutting apparatus of Fig. 7. The same parts as shown in Fig.7 are indicated by the same reference numerals in Fig.l.

The cutting apparatus includes a chuck table 41 for holding a work piece such as a semiconductor waf er W, a cutting unit 10 f or cutting the semiconductor wafer W on the chuck table 41 and means for f eeding coolant water to the place where the semiconductor waf er W is being cut.

In Fig - 1 the cutting unit 10 is shown along with a water f eeding means 16a and a blade watching means 18. In the cutting unit 10 a cutting blade 13 is attached to the end of a spindle with the aid of a f lange 14. The cutting blade 13 is surrounded by a blade cover 15, and the spindle is rotatably supported in a spindle housing 11. Specifically the spindle is air-suspended in the radial and thrust directions in the spindle housing 11.

Two water nozzles 16 and 17 are arranged under the blade cover 15 to extend in the X-direction, thus sandwiching the cutting blade 13 therebetween. The blade watching means 18 is placed on the top of the blade cover 15 to watch and detect breakage if any, in the rotating blade 13.

water inlets 19 and 20 project from the top of the blade cover 15. In dicing the semiconductor wafer W the coolant water is supplied to these water inlets 19 and 20 to be ejected from the nozzles 16 and 17 to the place where the rotating blade 13 is put in contact with the workpiece W for cooling, as best seen from Fig.2.

As a result water-and-debris mixture is scattered thereabout so that the cutting unit is contaminated with debris.

Referring to Fig-3, the cutting unit 10 includes the spindle housing 11 and the spindle 21, which has a blade mount 24 fixed to its end. The cutting blade 13 is attached to the spindle 21 with the aid of the blade mount 24. The spindle 21 is supported by the flow of air blown from radial and thrust bearings 22 and 23 in the radial and thrust directions. The cutting blade 13 is attached to the end of the spindle neck 12, which is exposed from 1 1 the spindle housing 11, by means of the blade mount 24 and the f lange 14. The structure described so f ar is similar to the conventional cutting units 4 3 and 4 7 of Figs. 8 and 9. The cutting unit 10 according to the present invention is dif f erent f rom these prior art cutting unit structures only in that it has an anti- contamination cover 25 attached to the end of the spindle housing 11 to cover the very small annular space 27 between the spindle 21 and the spindle housing 11, thereby preventing invasion of debris into the annular space 27.

Again referring to Fig.3, the anti-contamination cover 25 is detachably attached to the end of the spindle housing 11 by bolts in such a noncontact way that the anti-contamination cover 25 is apart more or less from the spindle neck 12, the spindle 21 and the blade mount 24.

Referring to Fig. 4, the anti-contamination cover 2 5 is an annular plate having a circular aperture 26 made at its center, and it has a thickness insufficient to allow the annular plate 25 to touch the blade mount 24 when fixed to the end of the spindle housing 11.

When the anti-contamination cover 25 is fixed to the end of the spindle housing 11, the annular space 27 between the spindle 11 and the spindle housing 11 is covered, and at the same time, the spindle neck 12 is covered, too. Thus, invasion of debris into the annular space 27 can be effectively prevented.

The blowing of air from the annular space 27 provides an air sealing at the end of the spindle housing 11. Specifically a narrow space is def ined between the blade mount 24 and the anti-contamination cover 2 5 to f orm an air passage in which the air blowing from the annular space 27 f lows, thereby f orming an umbrella-like spreading curtain of air 2 8, thus ef f ectively preventing invasion of debris into the spindle-and-housing space 27.

Referring to Fig.5. a cutting unit 30 has an upright wall-like blade mount 29 confronting the annular space 27. As seen fromFig.6, such a blade mount 29 is an annular plate 32 having a circular aperture much larger than that of the annular plate of Fig. 4, and is much thicker than the annular plate of Fig.4.

Referring to Fig.5, the anti-contamination cover 32 covers the annular area of the blade mount 29 and the spindle neck 12 to prevent effectively invasion of debris into the annular space 27 in cooperation with the blade mount 29. The air curtain 33 is formed as is the case with the cutting unit 10 of Fig.3.

Compared with the anti -contamination cover 2 5 as shown in Figs. 3 and 4, the area required f or attaching the anti-contamination cover 32 is small, and can be removed and attached easily. Therefore, the anti- contamination cover 32 can be cleaned easily.

As may be understood from the above, the anti -contamination cover can prevent debris from invading the very small space between the outer surface of the spindle and the inner surface of the spindle housing, and hence, the "scuf f ing- of these parts can be effectively prevented.

Also, advantageously the anti-contamination cover can be easily removed to facilitate the cleaning of the cutting unit.

Claims

Claims:

1. A spindle assembly comprising a spindle (21) having a blade mount (24 or 29) attached to its tip end for mounting a cutting 5 blade (13) thereto, and a housing (11) having the spindle air-suspended in the radial and thrust directions, characterized in that the housing (11) has an anti-contamination cover (25 or 32) placed between the cutting blade (13) and the spindle housing, thereby preventing debris from invading the space (27) between 10 the spindle and the housing.

2. A cutting apparatus comprising at least a chuck table (41) for holding a workpiece, a cutting unit (10 or 30) for cutting the workpiece on the chuck table, and means (16,17) for feeding 15 coolant water to the cutter for cooling, the cutting unit (10 or 30) including a spindle unit comprising a spindle (21) having a blade mount (24 or 29) attached to its end for mounting a cutting blade (13) thereto, and a housing (11) having the spindle air-suspended in the radial and thrust directions, characterized 20 in that the housing (11) has an anti-contamination Pover (25 or 32) placed between the cutting blade (13) and the spindle housing, thereby preventing debris from invading the space (27) between the spindle and the housing.

3. A cutting apparatus according to claim 2 wherein the anticontamination cover (25) is placed between the spindle housing (11) and the blade mount (24) to cover the space (27) between the spindle (21) and the spindle housing in non-contact condition.

4. A cutting apparatus according to claim 2 wherein the anticontamination cover (32) is placed to cover the neck (12) of the spindle (21) exposed from the spindle housing (11) and the blade mount (29) in non-contact condition.

1 9 -

5. A spindle assembly substantially as described herein with reference to Figs. 3 and 4 of the accompanying drawings.

6. A spindle assembly substantially as described herein with reference to Figs. 5 and 6 of the accompanying drawings.

7. A cutting unit substantially as described herein with reference to Figs. 1 to 4, or Figs. 1, 2, 5 and 6 of the accompanying drawings.

8. A cutting apparatus substantially as described herein with reference to Figs. 7 to 9 of the accompanying drawings and incorporating a spindle assembly or cutting unit as claimed in any one of Claims 5 to 7.