JP2000094317A - Polishing device for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrate a rotary brush with a receiving base to make the device constitution compact, and efficiently perform the polishing process, in a device for polishing semiconductor-wafers. SOLUTION: A rotary brush 13 for cleaning chuck mechanisms is juxtaposed integrally with a receiving base 4, and below an index heat 5, the rotary brush is arranged along a rail 15a arranged on the same circle (C) passing through respective polishing disks 2a to 2c so that it can be advanced and retracted. Then, while a polished wafer W is conveyed to a cassette 7b by a conveying robot 8b, the sucking surface of the chuck mechanism can be cleaned by the rotary brush 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for polishing a surface of a semiconductor wafer such as a bare wafer, a device wafer, an SOI wafer, a magnetic head wafer, and a magnetic disk wafer.

[0002]

2. Description of the Related Art As a polishing apparatus of this kind, an index head for rotatably supporting a chuck mechanism is arranged above a base having a polishing disk, and a wafer is held by the chuck mechanism and the held wafer is held. To the polishing machine,
2. Description of the Related Art There has been known an apparatus configured to rotate a polishing machine and a chuck mechanism mutually to perform wafer polishing.

[0003] More specifically, FIG.
No. 234870 and No. 10-208540 show examples of the apparatus shown in this specification. This polishing apparatus comprises three polishing disks (hereinafter referred to as polishers) 110 on a base 100,
A cradle 120 for one wafer W is arranged around an arbitrary point O on the same circumference so as to form an angle of 90 ° with respect to the point O, and the point O is used as a rotation axis. Axis 180
Are protruded from the base 100, and four chuck mechanisms 130 are also rotated by the rotation shaft 180 so that
An index head (indicated by a broken line in the drawing) 140, which is arranged at an angle of 0 ° and rotatably supports them, is rotatably supported.
The five wafers W placed on the receiving table 120 by 50 are collectively held by each chuck mechanism, and the index head 140 is rotated by 90 ° to be guided to each polisher, and the wafer W is pressed by each polisher. Then, the chuck mechanism and the polishing plate are rotated to polish the surface of the wafer W. In the figure, reference numeral 16 is used.
Reference numerals 0a and 160b denote cassettes in which wafers W before and after polishing are loaded, and 170 denotes a pad conditioner provided with each polisher.

Then, the wafer W, the surface of which has been polished through all the polishers 110, is again placed on the receiving table 120 and then transferred to the cassette 160b by the transfer robot 150.
Had been transferred to The chuck mechanism 130 that has released the holding of the wafer W guides a rotating brush (not shown) to the holding surface, rotates the brush to clean the surface, and wipes off dust and dirt attached in the polishing process. Had become.

[0005]

SUMMARY OF THE INVENTION The chuck mechanism 13 described above.
The cleaning of the holding surface with a rotating brush by a new brush W
Although it is indispensable to securely hold the flatness of the polished wafer W, if the rotating brush is provided so as to be able to advance and retreat from a position parallel to the cassette side, the device structure becomes complicated, There is a problem that the entire polishing apparatus cannot be made compact.

The present invention has been made in view of the above-mentioned problems in the prior art, and in a polishing apparatus for polishing a semiconductor wafer, a rotary brush is integrated with a receiving table to reduce the size of the apparatus and to efficiently perform polishing. An object is to enable processing.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a plurality of (n-unit;
(n is an integer of 2 to 4) a polishing base arranged on the same circumference, and an index formed by rotatably supporting a plurality of (n + 1) chuck mechanisms above the base. A head, a wafer receiving table on which a wafer before polishing transferred from the cassette and a wafer after polishing transferred by the chuck mechanism are mounted, the wafer is held by the chuck mechanism from the back surface, and the surface is , And a rotary brush for cleaning the chuck mechanism is arranged in parallel with the receiving table, and they intersect on the circumference integrally below the index head. It is characterized by being provided so as to be able to advance and retreat on a straight line passing through a point.

In the above construction, a rail having an appropriate length is arranged on a base, and a receiving plate on which a wafer is mounted and a rotary brush are serially arranged in the moving direction on a frame provided reciprocally along the rail. Side by side to form a cradle.

In the above structure, the wafer mounted on the pedestal is held by the chuck mechanism at a position where the circumference intersects with the pedestal, and the wafer before polishing is held on one side of the rail sandwiching the intersection. Is transferred from the cassette to the receiving table, and the wafer after polishing is transferred from the receiving table to the cassette on the other side.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 shows a configuration of an embodiment of a polishing apparatus according to the present invention. In the figure, reference numeral 1 denotes a base, 2a, 2
b and 2c are polishers; 3, 3 and 3 are pad conditioners attached to each polisher; 4 is a pedestal for receiving a wafer; 5 is an index head; 6a, 6b and 6;
c and 6d are chuck mechanisms, 7a and 7b are cassettes in which wafers W are loaded, 8a and 8b are transfer robots, 9 is a wafer cleaning mechanism, and W is a wafer.

The base 1 is provided with three polishers 2a to 2c and a pad conditioner 3 on its upper surface. Each polisher is arranged on the circumference of a circle C centered on an arbitrary point O on the upper surface of the base 1. The polishers 2a and 2c are located at opposing positions with the point O interposed therebetween. Equidistantly spaced,
That is, they are arranged at a 90 ° angle with respect to the point O. It should be noted that when a cradle 4 to be described later is positioned on the circumference of the circle C, the polisher 2b and the cradle 4 are opposed to each other at an angle of 180 ° with respect to the point O.

In each polisher, the polisher 2a performs rough polishing, the polisher 2b performs medium finish polishing, and the polisher 2c performs finish polishing. The lower portion of the polisher is supported by the rotating shaft 10, as shown in FIG. It is provided rotatably, and a polishing cloth 11 is attached to the surface thereof. Each polisher is provided with a pad conditioner 3 which advances and retreats linearly on the upper surface of the polishing cloth 11 and rotates to repair the polishing cloth 11.

The receiving table 4 is formed by integrating two receiving plates 12, 12 on which the wafers W before and after polishing are placed, and one rotating brush 13 for cleaning the suction surface of the chuck mechanism.
And it is provided so that it can slide linearly by the side of the polisher. More specifically, as shown in FIGS. 4 to 6, the receiving base 4 includes receiving plates 12, 12, a rotating brush 13, and a frame 14 for supporting the rotating brushes 13, It is configured to be connected to the installed drive mechanism 15 via a connection plate 15e.

The receiving plates 12 and 12 are provided with locking members 12
a is provided on the upper surface of the wafer W
Is formed so as to be placed. The rotating brush 13
A substantially cross-shaped disc 13b having a brush 13a protruding upward is fixed to a rotary shaft connected to a drive shaft of a motor 13c and is rotatably provided. The frame 14 has a box shape, and on its upper surface, the receiving plates 12, 12 and the rotating brush 13 are attached in series along the moving direction of the receiving table 4, and a drive motor 13c of the rotating brush 13 is fixed inside the frame. I have.

The drive mechanism 15 has a rail 15a of an appropriate length arranged horizontally in the base 1, and a movable body 15b is slidably mounted on this rail, and the movable body is rail-mounted by a servomotor 15c and a ball screw rod 15d. It is provided so that it can reciprocate along. The rail 15a is installed at a position crossing slightly outside the circumference of the circle C (see FIG. 4).

The frame 14 is integrally connected to a moving body 15b of a driving mechanism 15 via a connecting plate 15e.
4, and reciprocates along the rail. As shown in FIG. 4, when the receiving table 4 is located substantially at the center of the rail 15a, the receiving table 12 intersects the outer circumference of the circle C and the receiving plates 12, 12 are moved. It is located below the two suction mechanisms 23, 23 constituting the chuck mechanism, and is located substantially outside the circle C when the receiving table 4 is at both ends of the rail 15a.
Further, when the receiving table 4 moves to the end of the rail 15a on the cassette 7b side (the right end in FIG. 4), the rotating brush 13 is positioned below the suction mechanism 23 on one side. .

The index head 5 is rotatably supported by a hollow rotary shaft 16 projecting above the base 1 with the center point O of the circle C as a rotation axis (FIG. 2). ), At a position below and substantially along the circumference of the circle C,
The four sets of chuck mechanisms 6a to 6d are equally spaced from each other,
That is, the positions are shifted from each other by 90 ° with respect to the point O. As shown in FIG. 2, a vacuum pump 17 and a compressor 18 are provided in the hollow portion of the rotating shaft 16.
Eight rigid utility pipes 21a are inserted to connect the cleaning liquid tank 19 to the cleaning liquid tank 19 by switching the open / close valve 20, and decompressed air and pressurized air are supplied to each chuck mechanism via a flexible pipe 22 described later. In addition, necessary utilities such as cleaning liquid can be supplied.

Each of the chuck mechanisms is configured to operate integrally with the two suction mechanisms 23 as a set. Each suction mechanism 23 is attached downward near the edge of the index head 5, and as shown in FIG. 3, a circular frame is attached to the tip of a hollow rotary shaft 24 into which a rigid utility pipe 21b is inserted. A head 25 made of a material is attached, and a suction plate 26 having a large number of small holes 26a is mounted in the frame of the head 25, and rotated about a vertical axis by a motor 27 disposed above the index head 5. The movement is also given a vertical axial movement by the air cylinder 28, and the utility pipe 23 is connected to the utility pipe 21 of the index head 5 via the flexible pipe 22, and the necessary utility is provided in the head. The service pipe 2 is formed so as to supply a role.
Vacuum pump 17 through 1a, 21b and flexible tube 22
, And the pressure inside the head is reduced by a vacuum pump so that the wafer W is sucked to the suction plate 26 and held there. In addition, the compressor 18 and the washing liquid tank 19 are connected by switching the open / close valve 20. The cleaning liquid cleans the small holes 26a of the suction plate 26, and the pressurized gas facilitates the separation of the wafer W from the suction plate 26.

The cassette 7a is loaded with unpolished wafers W. When the receiving table 4 is positioned on the cassette side, the wafers W in the cassette are transferred to the transfer robot 8a.
Are sequentially transferred to the receiving table 4. The cassette 7b is loaded with the polished wafers W. When the receiving table 4 is located on the cassette side, the wafer W that has undergone the polishing process is transferred from the receiving table 4 by the transfer robot 8b. It is to be transported.

The wafer cleaning mechanism 9 cleans the polished wafer W by jetting a cleaning liquid onto the wafer W.

Next, a description will be given of a polishing process of the wafer W by the polishing apparatus of the present embodiment configured as described above.

(1) First, the transfer robot 8a is operated to transfer the wafer W before polishing from the cassette 7a to the receiving table 4. The cradle 4 is placed at the end of the rail 15a on the cassette 7a side, that is, at a position indicated by a solid line in FIG. 1, and the transfer robot 8a transfers the wafer W from the cassette 7a to the receiving plate 12 on the right side of the cradle 4. Transfer and place. continue,
The receiving table 4 is moved to the right by one wafer, and the wafer W is transferred from the cassette 7a to the receiving plate 12 on the left. Next, the cradle 4 is moved along the rail 15a to the front of the index head 5, and the chuck mechanism 6a is moved at that position.
Is lowered, and the two wafers W placed on the receiving table 4 are sucked and held, and then the chuck mechanism is raised. The chuck mechanism 6a holds the wafer W from the back.

(2) The index head 5 is rotated 90 ° clockwise in FIG. 1 to guide the wafer W held by the chuck mechanism 6a onto the first polisher 2a, and the chuck mechanism 6a is lowered to move the wafer W W is pressed against the polisher 2a, and the rotating shafts 10, 24 are rotated to roughly polish the surface of the wafer W. After the polishing, the chuck mechanism 6
a is raised and moved on the polisher. In the meantime, the receiving table 4 is returned to the end position on the cassette 7a side, and the wafers W are sequentially placed from the cassette 7a on the right receiving plate 12 and the left receiving plate 12 of the receiving table 4 in the same manner as described above. 4 is the rail 1 to the center of the index head 5
After the wafer W is moved along 5a and the two wafers W are sucked and held by the chuck mechanism 6b, the chuck mechanism is raised above the receiving table 4.

(3) The index head 5 is rotated 90 ° in the same direction as described above, and the wafer W held by the chuck mechanism 6a is placed on the second polisher 2b.
b is guided on the first polisher 2a, and both chuck mechanisms 6a and 6b are lowered.
Each of the polishers 2b performs medium finish polishing of the wafer W, and the polisher 2a performs rough finish polishing of the wafer W.
When the polishing is completed, each chuck mechanism is raised and moved on the polisher. During this time, the receiving table 4 is returned to the end position on the cassette 7a side, new wafers W are sequentially placed on the receiving table 4 from the cassette 7a in the same manner as described above, and the receiving table 4 is further moved to the center of the index head 5, and After the two wafers W are sucked and held by the mechanism 6c, the chuck mechanism is raised above the receiving table 4.

(4) The index head 5 is further rotated by 90 ° in the same manner as described above, and the wafer W held by the chuck mechanism 6a is placed on the third polisher 2c, and the wafer W held by the chuck mechanism 6b is placed on the third polisher 2c. 2 polishers 2b
The wafers W held by the chuck mechanisms 6c are respectively guided onto the first polisher 2a, and each chuck mechanism 6c
a, 6b and 6c are lowered, and the polisher 2c
And finish polishing of the wafer W by the polisher 2b, and finish polishing of the wafer W by the polisher 2a.
Rough finish polishing. When the polishing is completed in each polisher, each chuck mechanism is raised and moved on the corresponding polisher. During this time, the receiving table 4 is moved to the cassette 7a.
And the new wafers W are sequentially placed on the receiving table 4 from the cassette 7a in the same manner as described above.
Is moved to the center of the index head 5, and two wafers W are sucked and held by the chuck mechanism 6d, and then the chuck mechanism is raised above the receiving table 4. After the wafer W is attracted to the chuck mechanism 6d, the receiving table 4 is fixed to the center of the index head 5.

(5) Further, the index head 5 is rotated by 90 ° in the same manner as described above, the wafer W polished by the third polisher 2c is guided onto the receiving table 4, the chuck mechanism 6a is lowered, and vacuum suction is performed. The wafer W is stopped and the pressurized air is sent into the rotary shaft 24 to place the wafers W on the receiving plates 12 and 12 of the receiving table 4 and the cleaning liquid is ejected from the wafer cleaning mechanism 9 to clean the suction surface (back surface) of the wafer W. .

When the polished wafer W is placed on the receiving table 4, the receiving table 4 is moved to the right by one wafer from the center of the index head 5 in FIGS. The wafer W placed on the receiving plate 12 on the right side of the receiving table 4 is transferred to the cassette 7b.
The rotating brush 13 is brought into contact with the suction surface of the suction mechanism 23 on one side (left side) of the chuck mechanism 6a, and the brush is rotated and rubbed to wipe off dirt. Then, the receiving table 4 is further moved rightward by one wafer. Further, the wafer W placed on the receiving plate 12 on the left side of the receiving table 4 is transferred to the cassette 7b by the transfer robot 8b, during which the suction surface of the suction mechanism 23 on the other side (right side) of the chuck mechanism 6a rotates. The brush 13 is brought into contact, and the brush is rotated and rubbed to remove dirt. As described above, while the polished wafer W is being transferred to the cassette 7b, the rotary brush 13 cleans the suction surface of the chuck mechanism 6a.

After the cleaning of the chuck mechanism 6a by the rotating brush 13 is completed, the receiving table 4 is moved to the end on the cassette 7a side to place a new wafer W thereon, and is again moved to the center of the index head 5, and a new one is moved. The wafer W is held by the chuck mechanism 6a. After the wafer W is attracted to the chuck mechanism 6a, the receiving table 4 is fixed to the center of the rail 15a.

In the meantime, the wafer W polished by the second polisher 2b is used for the third polisher 2c, the wafer W polished by the first polisher 2a is used for the second polisher 2b, and the chuck mechanism 6d is used. The wafers W attracted to the wafer W are respectively guided to the first polishers 2a, the chuck mechanisms are lowered, and the wafers W are polished by the respective polishers in the same manner as described above.

(6) Thereafter, in the same manner, the wafer W associated with the rotation of the index head 5 every 90 ° and the movement of the receiving table 4
The wafer W is continuously polished while being transferred from the cassette 7a, transferred to the cassette 7b, the suction surface of the chuck mechanism is cleaned by the rotating brush 13, and the polisher is polished.

The above-described embodiment is merely an example, and the arrangement and number of the polishers and chuck mechanisms can be appropriately determined. For example, the rotation of the index head 5 in the step (6) is performed by 270 ° in the reverse direction (counterclockwise).
The rotation may be performed. The cleaning of the chuck mechanism by the rotating brush 13 may be performed in a different order from the above, and the cradle 4 may be moved independently of the transfer of the wafer W to clean the chuck mechanism by the rotating brush 13.

In transfer of a new wafer W, the pedestal 4
Is not moved to the right by one wafer, and the pair of right and left cassettes 7 is rotated by the rotation of the transfer robot 8a about the axis.
a, 7a, the wafer W transferred from the left cassette 7a is placed on the right receiving plate 12 on the receiving table 4, and the wafer W transferred from the right cassette 7a is placed on the left receiving plate 12 on the receiving table 4. May be placed on the server. The width of rotation of the transfer robot 8a about the axis is increased, and the wafer W is placed on the left and right receiving plates 12 from the left cassette 7a. When the cassette is empty, the wafer is moved from the right cassette 7a. W may be placed on the receiving table 4.

Further, it is desirable that the polishing in each of the polishers be completed simultaneously. Accordingly, the start time of the finish polishing in the third polisher 2c, which requires a relatively short polishing time, is delayed from the start time of the rough polishing in the first polisher 2a and the start time of the medium finish polishing in the second polisher 2b. The polishing may be adjusted simultaneously with a polisher.

Different types of wafers W can be stored in the respective cassettes 7a, 7a and polished. Further, when the demand for the wafer W is small, only one of the pair of suction mechanisms constituting the chuck mechanism may be operated, and the other may not be operated.

As an embodiment of the apparatus of the present invention, the polishing stage (polisher) has n (n is an integer of 2 to 5), loading (transfer of the wafer before polishing from the cassette), and unloading (after polishing to the cassette). Wafer transfer) is 1
When the entire stage is the (n + 1) stage, the rotation of the index head is 360 / (n + 1) degrees, and the number of chuck mechanisms is (n + 1). That is, when the polishing stage is a two-stage of rough polishing and finish polishing, the chuck mechanism is three.
Basically, the rotation of the index head is 120 degrees.

[0036]

As described above, the wafer polishing apparatus of the present invention has two receiving plates and one rotating brush which are integrally arranged side by side on a receiving table so that they can be reciprocated linearly. Since the rotary brush is provided on the base, the apparatus can be made more compact and the transfer of the wafer and the cleaning of the chuck mechanism can be performed as compared with the case where the rotary brush is driven separately.

Further, since the receiving table is formed by arranging the receiving plate on which the wafer is mounted and the rotating brush in series along the moving direction, the wafer is transferred to the cassette and the chuck mechanism is attracted to the chuck mechanism by the rotating brush. The surface can be cleaned, the polishing process can be made more efficient, and the overall processing time can be reduced.

Further, the receiving table is slidably provided along a rail provided on the base so that the wafer can be attracted to the chuck mechanism at the center of the rail, and the wafer is transferred to and from the cassette on both sides thereof. By configuring
A cassette for storing wafers before and after polishing and a transfer robot for transferring the cassette are arranged on both sides of the rail, so that the wafer can be efficiently transferred between the receiving table and the cassette.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an embodiment of a polishing apparatus of the present invention.

FIG. 2 is a schematic sectional view of the polishing apparatus of FIG.

FIG. 3 is a diagram illustrating a configuration of a chuck mechanism.

FIG. 4 is a diagram showing a configuration of a cradle.

FIG. 5 shows a rotating brush attached to a cradle;
(A) is a schematic plan view, and (B) is a cross-sectional view along the line V-V of (A).

FIG. 6 is a schematic sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is a plan view showing a configuration of a conventional polishing apparatus.

[Explanation of symbols]

 1 base 2a ~ 2c polisher (polishing machine) 4 receiving table 5 index head 6a ~ 6d chuck mechanism 7a, 7b cassette 8a, 8b transfer robot 13 rotating brush 15 drive mechanism 15a rail O center C circle W wafer

Continued on the front page (72) Inventor Satoru Ide 3009 Uechi, Atsugi-city, Kanagawa Prefecture Inside the Semiconductor Division of Okamoto Machine Tool Works, Ltd. (72) Inventor Junyuki Mochimaru 3009, Kamiyori, Atsugi-shi, Kanagawa Prefecture Semiconductor Business of Okamoto Machine Tool Works, Ltd. Department F-term (reference) 3C058 AA07 AA11 AA16 AA18 AB06 AB08 BC01 BC02 CB03 DA17

Claims (3)

[Claims] 1. A base having a plurality of polishing machines arranged on the same circumference, an index head having a plurality of chuck mechanisms rotatably supported above the base, and a transfer from a cassette. A wafer receiving table on which a wafer before polishing and a wafer after polishing transferred by the chuck mechanism are placed. The wafer is held by the chuck mechanism from the back side, and the surface is pressed against the polishing plate to make the wafer surface In a wafer polishing apparatus for performing polishing, a rotary brush for cleaning a chuck mechanism is arranged side by side on the receiving table, and these are integrally moved below an index head so as to be able to advance and retreat in a linear direction so as to intersect the circumference. An apparatus for polishing a wafer, comprising: 2. A receiving plate on which a wafer is placed and a rotary brush are arranged in series in the moving direction on a frame provided with a rail having an appropriate length on a base and reciprocally movable along the rail. The wafer polishing apparatus according to claim 1, further comprising a table. And a chuck mechanism for holding a wafer placed on the pedestal at a position where the circumference and the pedestal intersect, and receiving a wafer before polishing from a cassette on one side of a rail sandwiching the intersection. 3. The wafer polishing apparatus according to claim 1, wherein the wafer polishing apparatus is configured to transfer the polished wafer from the receiving table to the cassette on the other side.