JP2004079749A - Machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining apparatus which can prevent the impact resulting from the deflection by thermal distortion of a chuck table by suppressing the occurrence of thermal distortion of the chuck table for holding a workpiece to the minimum. <P>SOLUTION: The machining apparatus comprises a chuck table mechanism 5 having the chuck table 50 for holding a workpiece and a rotation driving means 60 for rotating the chuck table, a machining means for machining the workpiece held by the chuck table while supplying a machining liquid to the workpiece, and a machining liquid pan 211 which is formed with a hole to insert the chuck table therein and is arranged below an upper surface of the chuck table. The chuck table of the chuck table mechanism comprises a chuck plate 51 which is formed out of a porous material and chucks and holds the workpiece, a chuck plate supporting board 52 which supports the chuck plate by its upper surface, and an annular heat radiation board 53 which is mounted in the periphery of the chuck plate supporting board and is equipped with a heat radiation section 531 extended radially. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a processing apparatus such as a polishing apparatus for polishing a workpiece such as a semiconductor wafer.
[0002]
[Prior art]
A semiconductor wafer serving as a substrate on which circuits such as ICs and LSIs are stacked is obtained by slicing a silicon ingot into a wafer, grinding both sides of the sliced semiconductor wafer with a lapping device or a double-side grinding device, and then polishing the semiconductor wafer with a polishing device. It is formed by a processing technique called so-called wafer making in which the surface is polished to a mirror surface.
[0003]
It takes a considerable amount of time to polish the surface of a semiconductor wafer to a mirror surface by the above-described polishing apparatus, and there is a problem that productivity is poor. In order to reduce the polishing time by this polishing apparatus, before polishing the surface of the semiconductor wafer ground by the lapping apparatus or the double-side grinding apparatus, a chuck table for holding the workpiece and the chuck table are rotationally driven. A step of polishing a surface of a semiconductor wafer by using a polishing apparatus having a chuck table mechanism having a rotation driving means, and a polishing means for performing polishing while supplying a processing liquid to a workpiece held by the chuck table; Has been implemented.
[0004]
[Problems to be solved by the invention]
Thus, the semiconductor wafer, the surface of which has been polished by the polishing apparatus, has a slightly raised central portion. Therefore, even if the surface of the semiconductor wafer is polished using a polishing apparatus before polishing, the polishing time for polishing cannot always be sufficiently reduced.
[0005]
It is considered that the cause of the bulging at the central portion of the polished semiconductor wafer as described above is caused by the curvature of the chuck table holding the semiconductor wafer due to thermal distortion. Note that the influence of the bending due to the thermal distortion of the chuck table appears in other processing apparatuses other than the above-described polishing apparatus.
The present invention has been made in view of the above-described facts, and its main technical problem is to minimize the occurrence of thermal distortion of a chuck table that holds a workpiece, and to reduce the influence due to the bending due to the thermal distortion of the chuck table. It is an object of the present invention to provide a processing device capable of preventing the occurrence of the processing.
[0006]
[Means for Solving the Problems]
In order to solve the main technical problem, according to the present invention, a chuck table mechanism having a chuck table for holding a workpiece and rotation driving means for rotating the chuck table is provided, and a chuck table mechanism held on the chuck table. A processing apparatus comprising: processing means for performing processing while supplying a processing liquid to a workpiece; and a processing liquid receiving tray provided with a hole through which the chuck table is inserted and disposed below an upper surface of the chuck table.
The chuck table of the chuck table mechanism includes a chuck plate made of a porous member and holding the workpiece by suction, a chuck plate support substrate that supports the chuck plate on the upper surface, and an outer peripheral portion of the chuck plate support substrate. An annular radiator plate provided with a radiator portion that is mounted and extends in the radial direction.
A processing device is provided.
[0007]
A cylindrical hanging portion is provided on the outer periphery of the heat sink, and a cylindrical upright portion is provided upright on a periphery of a hole formed in the processing liquid receiving tray. It is arranged so as to fit loosely on the outside of the upright portion. Preferably, the chuck plate support substrate and the heat radiating plate are formed of a metal material.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of a processing apparatus configured according to the present invention will be described in detail with reference to the accompanying drawings.
[0009]
FIG. 1 is a perspective view of a polishing apparatus as a processing apparatus configured according to the present invention.
The illustrated polishing apparatus comprises an apparatus housing, generally designated by the numeral 2. The device housing 2 has a rectangular main body 21 that is elongated and an upright wall 22 that is provided at a rear end (upper right end in FIG. 1) of the main part 21 and extends substantially vertically upward. I have. In the illustrated embodiment, two grinding lines 2a and 2b are provided in parallel in the apparatus housing 2 configured as described above. Since the respective mechanisms constituting the two grinding lines 2a and 2b are substantially the same, the same mechanisms will be described with the same reference numerals.
A pair of guide rails 221 and 221 extending in the vertical direction are provided on the front surface of the upright wall 22 that forms the device housing 2. The grinding unit 3 is mounted on the pair of guide rails 221 and 221 so as to be vertically movable.
[0010]
The polishing unit 3 includes a moving base 31 and a spindle unit 32 mounted on the moving base 31. The movable base 31 is provided with a pair of legs 311, 311 vertically extending on both sides of the rear surface, and slidably engages the pair of guide rails 221, 221 with the pair of legs 311, 311. Guide grooves are formed. As described above, a support portion 313 protruding forward is provided on the front surface of the movable base 31 slidably mounted on the pair of guide rails 221 and 221 provided on the upright wall 22. The spindle unit 32 as a polishing means is attached to the support portion 313.
[0011]
The spindle unit 32 includes a spindle housing 321 mounted on the support 313, a rotary spindle 322 rotatably disposed on the spindle housing 321, and a servomotor as a drive source for driving the rotary spindle 322 to rotate. 323, and the output shaft of the servo motor 323 is operatively connected to the rotary spindle 322. The lower end of the rotary spindle 322 projects downward beyond the lower end of the spindle housing 321, and a polishing tool 325 is attached to the lower end. A machining fluid supply passage (not shown) for supplying a machining fluid is formed at the center of the rotary spindle 322 so that the machining fluid is supplied to the polishing section of the polishing tool 325 through the machining fluid supply passage. It has become.
[0012]
The polishing apparatus in the illustrated embodiment includes a polishing unit feed mechanism 4 for moving the polishing unit 3 in a vertical direction (a direction perpendicular to a mounting surface of a chuck table described later) along the pair of guide rails 221 and 221. Have. The polishing unit feed mechanism 4 includes a male screw rod 41 disposed on the front side of the upright wall 22 and extending substantially vertically. The male screw rod 41 is rotatably supported at its upper end and lower end by bearing members 42 and 43 attached to the upright wall 22. The upper bearing member 42 is provided with a pulse motor 44 as a drive source for rotationally driving the male screw rod 41, and the output shaft of the pulse motor 44 is operatively connected to the male screw rod 41. A connecting portion (not shown) projecting rearward from the center portion in the width direction is also formed on the rear surface of the movable base 31, and a penetrating female screw hole extending in the vertical direction is formed in this connecting portion. The male screw rod 41 is screwed into the female screw hole. Therefore, when the pulse motor 44 rotates forward, the moving base 31, that is, the polishing unit 3 is lowered, and when the pulse motor 44 rotates reversely, the moving base 31, that is, the polishing unit 3 is raised.
[0013]
The polishing apparatus in the illustrated embodiment includes a chuck table mechanism 5 disposed below the polishing unit 3 at the rear of the main part 21 of the housing 2.
The chuck table mechanism 5 will be described with reference to FIGS. The chuck table mechanism 5 in the illustrated embodiment includes a chuck table 50 that holds a workpiece, and a rotation driving unit 60 that drives the chuck table 50 to rotate. The chuck table 50 includes a chuck plate 51 that holds the workpiece by suction, a chuck plate support substrate 52 that supports the chuck plate 51 on the upper surface, and a heat radiating plate 53 that is mounted on an outer peripheral portion of the chuck plate support substrate 52. Consists of The chuck table 50 is inserted above a hole 211 a formed in a processing liquid receiving tray 211 for receiving a processing liquid disposed on the main portion 21 of the housing 2, and is disposed above the upper surface of the processing liquid receiving tray 211. The machining liquid receiving tray 211 is provided with a cylindrical upright portion 211b formed to protrude upward from the periphery of the hole 211a.
[0014]
The chuck plate 51 constituting the chuck table 50 has a disk-shaped adsorption member 511 made of an appropriate porous material such as porous ceramics, and an annular shape made of a ceramic material such as alumina fitted on the outer periphery of the adsorption member 511. The outer peripheral surface of the suction member 511 and the inner peripheral surface of the mounting member 512 are sintered and bonded by a vitreous binder. Note that a step 512a is formed on the outer periphery of the annular mounting member 512, and a plurality of bolt insertion holes 512b penetrating in the axial direction is formed in the step 512a.
[0015]
The chuck plate supporting substrate 52 constituting the chuck table 50 is formed in a disk shape from a metal material having good heat conductivity, and includes a chuck plate supporting portion 521 and a heat radiating plate formed on the outer peripheral side of the chuck plate supporting portion 521. And a mounting portion 522. The chuck plate support portion 521 has a plurality of screw holes 521a formed at positions corresponding to the plurality of bolt insertion holes 512b formed in the mounting portion 512 of the chuck plate 51. The chuck plate support 521 is provided with suction chambers 521b and 521c formed by a circular recess and an annular recess on the upper surface thereof, and suction passages 521d and 521e communicating with the suction chambers 521b and 521c. , 521f are provided. The heat sink mounting portion 522 formed on the outer peripheral side of the chuck plate support portion 521 is formed with a step below the upper surface of the chuck plate support portion 521, and has a plurality of screw holes 522a penetrating in the axial direction. Is formed. The chuck plate 51 is placed on the upper surface of the chuck plate supporting portion 521 constituting the chuck plate supporting substrate 52 configured as described above, and the plurality of bolt insertion holes 512b formed in the step portion 512a of the mounting member 512 are inserted. The bolt 54 is screwed into a screw hole 521a formed in the chuck plate support 521, so that the chuck plate 51 is mounted on the upper surface of the chuck plate support 521.
[0016]
The heat radiating plate 53 constituting the chuck table 50 is formed in a ring shape from a metal material having good heat conductivity. The heat radiating plate 53 has a fitting hole 531 a that fits with the chuck plate supporting portion 521 of the chuck plate supporting substrate 52 and a radially extending heat radiating portion 531, and a cylinder that hangs downward from an outer peripheral edge of the heat radiating portion 531. A plurality of bolts are provided at positions corresponding to a plurality of screw holes 522a formed in the heat sink mounting portion 522 of the chuck plate support substrate 52 on the inner peripheral portion of the heat sink 531. An insertion hole 531b is formed. The radiator plate 53 configured as described above fits the fitting hole 531a into the chuck plate support portion 521 of the chuck plate support substrate 52, and places the inner peripheral portion of the radiator portion 531 on the radiator plate mounting portion 522. The bolts 55 provided through the plurality of bolt insertion holes 531b formed in the inner peripheral portion of the heat radiating portion 531 are screwed into the plurality of screw holes 522a provided in the heat sink mounting portion 522. As a result, the radiator plate 53 is mounted on the radiator plate mounting portion 522 of the chuck plate support substrate 52. The cylindrical hanging portion 532 constituting the heat sink 53 is loosely fitted to the outside of the cylindrical upright portion 211b provided on the processing liquid receiving tray 211.
[0017]
The rotation driving means 60 for rotating and driving the chuck table 50 includes a chuck table shaft 61 connected to the lower surface of the chuck plate support substrate 52 by an appropriate connecting means, and a rotary attached to the lower end of the chuck table shaft 61. It is constituted by a joint 62 and an electric motor 63 that drives the chuck table shaft 61 to rotate. The chuck table shaft 61 is formed in a cylindrical shape with an appropriate metal material, and has a small diameter portion at a lower portion thereof. The thus formed chuck table shaft 61 has a circular concave portion 61a and an annular concave portion 61b communicating with the suction passages 521d and 521e, 521f formed in the chuck plate supporting substrate 52 constituting the chuck table 50, and the circular circular portion 61b. A suction passage 61c communicating with the concave portion 61a and the annular concave portion 61b, and a suction passage 61d communicating with the suction passage 61c and opening on the outer peripheral surface of the small diameter portion are provided. The roller joint 62 is formed of an appropriate metal material in an annular shape, and is fitted to the small diameter portion of the chuck table shaft 61 so as to be relatively rotatable. An annular suction passage 62a communicating with a suction passage 61b formed in a small diameter portion of the chuck table shaft 61 is provided on an inner peripheral surface of the rotary joint 62, and a suction passage 62b communicating with the suction passage 62a and opening on the outer peripheral surface. Is provided, and the suction passage 62b is connected to a negative pressure control circuit including a negative pressure source (not shown) via the flexible pipe 64. The electric motor 63 for rotating and driving the chuck table shaft 61 has its drive shaft 631 connected to the lower surface of the chuck table shaft 61 by an appropriate connecting means.
[0018]
The chuck table mechanism 5 is configured as described above. When the flexible pipe 64 communicates with a negative pressure source (not shown) by controlling a negative pressure control circuit (not shown), the suction passages 62b, 62a, 61d, 61c, and the circular recess 61a are formed. The negative pressure acts on the suction member 511 made of a porous material of the chuck plate 51 constituting the chuck table 50 through the annular concave portion 61b, the suction passages 521d, 521e, 521f and the suction chambers 521b, 521c. As a result, when the workpiece is placed on the upper surface of the chuck plate 51, the workpiece is suction-held on the chuck plate 51 by the negative pressure.
[0019]
Returning to FIG. 1, in the main part 21 of the apparatus housing 2, in front of the chuck table mechanisms 5, 5, a cassette mounting area 7, a transport means arrangement area 8, and a temporary storage area 9 and 9 are provided. Cassettes 70, 70 for accommodating circular workpieces such as semiconductor wafers are mounted in the cassette mounting areas 7, 7. The workpiece transfer means 80 is provided in the transfer means arrangement area 8. The workpiece transfer means 80 carries out the unprocessed workpieces stored in the cassettes 70, 70 and conveys them to the temporary storage areas 9, 9, and also transfers the ground workpieces to the temporary storage areas 9, 9, respectively. To the cassettes 70, 70. The temporary placement areas 9 and 9 include a center alignment and cleaning mechanism 90 having a centering function of the workpiece before grinding discharged from the cassettes 70 and 70 and a cleaning function of the workpiece after grinding. 90 are provided.
[0020]
Work loading / unloading means 10, 10 are arranged between the temporary placement areas 9, 9 and the chuck tables 50, 50. The workpiece loading / unloading means 10, 10 holds the workpiece before grinding center-aligned by the center alignment and cleaning mechanisms 90, 90 disposed in the temporary storage areas 9, 9, on the chuck table 50, In addition to transporting the workpiece onto the chuck table 50, the workpiece after grinding on the chuck table 50 is carried out to the center alignment and cleaning mechanisms 90, 90. The workpiece loading / unloading means 10 may be a well-known suction-type transport mechanism that is generally used.
[0021]
The polishing apparatus in the illustrated embodiment is configured as described above, and its processing operation will be described below mainly with reference to FIG.
The semiconductor wafer, which is a workpiece before grinding stored in the cassette 70 mounted on the cassette mounting area 7, is transported by vertical movement and forward / backward movement of the workpiece transporting means 80, and the temporary storage area 9. Is mounted on the center table 91 of the center alignment and cleaning mechanism 90 provided in the printer. The semiconductor wafer placed on the center table 91 is centered, and is placed on the chuck table 50 by the turning operation of the workpiece loading / unloading means 10. The semiconductor wafer mounted on the chuck table 50 is suction-held on the chuck plate 51 constituting the chuck table 50 by controlling the negative pressure control circuit (not shown) as described above.
[0022]
Next, the chuck table 50 holding the semiconductor wafer as the workpiece is rotated and the polishing tool 325 being driven to rotate presses the semiconductor wafer on the chuck table 50 with a predetermined pressure. The semiconductor wafer is polished. Due to this polishing action, high heat is generated in the polishing tool 325 and the semiconductor wafer to be processed. In order to cool this heat, at the time of polishing, the working fluid is supplied to the polishing section of the polishing tool 325 through a working fluid supply passage (not shown) provided at the center of the rotary spindle 322 to which the polishing tool 325 is mounted. . As a result, the heat generated by the polishing operation is absorbed to some extent by the working fluid, but the chuck plate 51 and the chuck plate supporting substrate 52 constituting the chuck table 50 are heated by the heat generated by the polishing operation. When the chuck plate 51 and the chuck plate support substrate 52 are heated, they are curved by thermal distortion, and thus the semiconductor wafer placed on the chuck plate 51 and polished is in a state in which the center portion is slightly raised.
[0023]
However, in the illustrated embodiment, since the heat radiating plate 53 is mounted on the outer peripheral portion of the chuck plate supporting substrate 52 constituting the chuck table 50, the processing liquid supplied to the polishing section constitutes the chuck table 50. From the outer periphery of the chuck plate 51 to fall on the heat radiating portion 531 of the heat radiating plate 53. As a result, since the heat radiating portion 531 is cooled by the working fluid, the chuck plate supporting substrate 52 connected to the heat radiating portion 531 is cooled, so that the temperature difference between the upper and lower surfaces of the chuck plate supporting substrate 52 becomes extremely small. . Therefore, the occurrence of thermal distortion of the chuck plate supporting substrate 52 is reduced as much as possible, and the influence of the bending due to the thermal distortion of the chuck table (the phenomenon that the central portion of the polished semiconductor wafer slightly rises) can be prevented. The working fluid that has fallen onto the heat radiating portion 531 of the heat radiating plate 53 flows to the outer peripheral portion, travels along the cylindrical hanging portion 532, and falls into the working fluid receiving tray 211. In the illustrated embodiment, the cylindrical hanging portion 532 of the heat radiating plate 53 is loosely fitted to the outside of the cylindrical upright portion 211b provided upright on the periphery of the hole 211a provided in the processing liquid receiving tray 211. Since it is disposed in such a manner, the machining fluid falling along the cylindrical hanging portion 532 does not flow out into the apparatus housing 2 through the hole 211a.
[0024]
When the grinding is completed as described above, the polishing tool 325 is separated upward from the semiconductor wafer on the chuck table 50, and the rotation of the polishing tool 325 and the chuck table 50 is stopped. Thereafter, the suction-holding of the semiconductor wafer, which is the polished workpiece on the chuck table 50, is released, and the ground semiconductor wafer released from the suction-holding is carried out by the workpiece loading / unloading means 10 to be removed. It is placed on the center table 91 of the positioning and cleaning mechanism 90. The polished semiconductor wafer conveyed to the center alignment and cleaning mechanism 90 in this way is subjected to spinner cleaning and dried. The semiconductor wafer, which has been transported to the center alignment and cleaning mechanism 90 and has been cleaned and dried and has been ground, is stored in a predetermined position of the cassette 60 by the workpiece transporting means 70.
[0025]
As described above, the present invention has been described based on the illustrated embodiments, but the present invention is not limited to only the embodiments. That is, in the illustrated embodiment, an example in which the present invention is applied to a polishing apparatus is shown. However, the present invention is widely applied to other processing apparatuses that perform processing such as cutting by suction-holding a workpiece on a chuck table. Can be applied.
[0026]
【The invention's effect】
The processing apparatus according to the present invention is configured as described above, and has the following effects.
That is, the chuck table for holding the workpiece is made of a porous member, a chuck plate for sucking and holding the workpiece, a chuck plate support substrate for supporting the chuck plate on the upper surface, and an outer periphery of the chuck plate support substrate. Since the machining fluid supplied at the time of machining is mounted on the heat radiating portion of the heat radiating plate from the outer periphery of the chuck plate constituting the chuck table, the heat sink is provided with an annular heat radiating plate having a radially extending heat radiating portion mounted on the portion. Since the heat radiating portion is cooled by the processing liquid, the chuck plate supporting substrate 52 connected to the heat radiating portion is cooled. Accordingly, the temperature difference between the upper and lower surfaces of the chuck plate supporting substrate is extremely small, and the occurrence of thermal distortion of the chuck plate supporting substrate is reduced as much as possible, thereby making it possible to prevent the influence due to the bending due to the thermal distortion.
[Brief description of the drawings]
FIG. 1 is a perspective view of a polishing apparatus as a processing apparatus configured according to the present invention.
FIG. 2 is a cross-sectional view of a chuck table mechanism provided in the polishing apparatus shown in FIG.
FIG. 3 is an exploded perspective view showing constituent members of the chuck table mechanism shown in FIG. 2;
[Explanation of symbols]
2: Apparatus housing 211: Working fluid receiving tray 3: Polishing unit 31: Moving base 32: Spindle unit 4: Grinding unit feed mechanism 41: Male screw rod 44: Pulse motor 5: Chuck table mechanism 50: Chuck table 51: Chuck plate 511 : Suction member 512: Mounting member 52: Chuck plate support substrate 521: Chuck plate support portion 522: Heat sink mounting portion 53: Heat sink 531: Heat sink 532: Cylindrical hanging part 60: Rotary drive means 61: Chuck table shaft 62 : Rotary joint 63: Electric motor 7: Cassette mounting area 70: Cassette 8: Transport means arrangement area 80: Workpiece transport means 9: Temporary placement area 90: Center alignment and cleaning mechanism 91: Center table 10: Workpiece Loading / unloading means

Claims (3)

A chuck table mechanism having a chuck table for holding a workpiece and a rotary drive unit for rotating and driving the chuck table; and a processing unit for performing processing while supplying a processing liquid to the workpiece held on the chuck table. A machining liquid receiving plate provided with a hole through which the chuck table is inserted and disposed below the upper surface of the chuck table,
The chuck table of the chuck table mechanism includes a chuck plate made of a porous member and holding the workpiece by suction, a chuck plate support substrate that supports the chuck plate on the upper surface, and an outer peripheral portion of the chuck plate support substrate. An annular radiator plate provided with a radiator portion that is mounted and extends in the radial direction.
A processing device characterized by the above-mentioned. A cylindrical hanging portion is provided on the outer periphery of the heat sink, and a cylindrical upright portion is provided upright on a peripheral edge of the hole formed in the working liquid receiving tray, and the cylindrical hanging portion is provided with the cylindrical hanging portion. The processing apparatus according to claim 1, wherein the processing apparatus is loosely fitted outside the cylindrical upright portion. The processing apparatus according to claim 1, wherein the chuck plate support substrate and the heat radiating plate are formed of a metal material.

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