JPH11320389A - Polishing head and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the production efficiency of a wafer polishing process to automatically exchange polishing cloth, unsuitable for polishing, with novel polishing cloth togetherwith a polishing platen. SOLUTION: A polishing head presses polishing cloth 13 against a wafer 2 with the polishing cloth 13 in the same direction as that of a wafer 2 rotated. The polishing head comprises a rotary shaft 34 rotatably supported in a housing 33 and connected to a drive motor 36; a polishing surface plate 11 having an under surface, on which the polishing cloth 13 is mounted, and a coupling part 42 mounted on and demounted from the rotary shaft 34; and an automatic mounting and demounting mechanism 38 to automatically removably couple a polishing surface plate 11 with the rotary shaft 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing head and a polishing apparatus for polishing a wafer, and more particularly, to a polishing head and a polishing apparatus which can be automatically replaced to easily replace a polishing cloth.

[0002]

2. Description of the Related Art Chemicals in semiconductor manufacturing processes
2. Description of the Related Art A polishing apparatus used for polishing a wafer in mechanical polishing processing has a chuck surface plate that rotates while holding a wafer, and a polishing surface plate to which a polishing cloth is attached. When polishing a wafer, the chuck platen and the polishing platen are rotated in the same direction. At this time, the polishing cloth on the polishing platen is pressed against the wafer at a predetermined pressure, and the polishing agent is supplied at the same time.

In recent polishing apparatuses, as the diameter of a wafer increases, a polishing plate having a polishing cloth smaller than the diameter of the wafer is used. The polishing head is mounted on the chuck surface plate, and is polished while giving a turning motion or a linear motion so as to pass through the center of the wafer on the chuck platen.

Since high flatness is required for the wafer, it is essential to appropriately dress the polishing cloth. If the polishing cloth becomes clogged, the polishing amount per unit time decreases, and the polishing amount cannot be controlled. Therefore, it is necessary to eliminate the clogging. As this dressing method, there is a method proposed by the present applicant in Japanese Patent Laid-Open No. Hei 10-550.

[0005] This dressing method for a polishing cloth uses a dresser grindstone to optimize the shape of the polishing cloth after dressing, and is suitable for automation of dressing of the polishing cloth, which has been conventionally performed empirically. In this way, it can be performed under objectively optimal conditions.

[0006]

However, when this dressing method is carried out, the polishing cloth is shaved by a dresser whetstone and becomes thinner. In order to maintain polishing accuracy, a polishing cloth which is no longer suitable for polishing is applied. I have to change it. In a conventional polishing head, the polishing platen is connected to a drive shaft for transmitting the rotation of a motor, and the polishing cloth is attached to the polishing platen using a double-sided tape. In polishing a wafer, the mounting accuracy of the polishing cloth on the polishing platen is also important. Therefore, if the polishing cloth is not correctly fixed to the polishing platen, an error occurs in the flatness of the wafer.When replacing the polishing cloth, remove the polishing platen from the shaft so as not to lower the polishing accuracy. You have to be strict and careful.

In particular, in the method of moving the polishing platen, it takes time to attach and detach the polishing platen and replace the polishing cloth. During this time, the polishing apparatus is stopped and the polishing operation is interrupted. There was a drawback that the rate decreased.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to improve the operating rate by automatically changing the polishing pad together with the polishing plate efficiently. And a polishing apparatus.

[0009]

In order to achieve the above object, a polishing head according to the present invention is a polishing head for pressing a polishing cloth against a wafer while rotating the polishing cloth in the same direction as a wafer. A rotating shaft that is rotatably supported by and connected to a drive motor, a polishing platen having the polishing cloth attached to a lower surface, and a connecting portion for attaching and detaching to and from the rotating shaft; And an automatic attachment / detachment mechanism for automatically attaching / detaching the surface plate.

According to a preferred embodiment, the automatic attachment / detachment mechanism is detachable from the first connection member fixed to the rotation shaft and the first connection member so that torque is transmitted from the rotation shaft. A second connecting member that constitutes the connecting portion of the polishing platen, a connecting element that connects the first connecting member and the second connecting member, and the connecting element that is provided on an inner diameter portion of the second connecting member. A receiving portion that releasably engages;
The first connection member is provided so as to be able to reciprocate by a working fluid supplied through the rotary shaft inside the rotation shaft, and the connection element is engaged with the receiving portion of the second connection member in a forward position in a restricting manner, A piston that becomes unrestrained only when it retreats,
have.

A polishing apparatus according to the present invention is a polishing apparatus for rotating a polishing cloth in the same direction as a wafer rotating on a surface plate and polishing the wafer with the polishing cloth while supplying an abrasive. A rotating polishing table, a rotating shaft rotatably supported in the housing and connected to a drive motor, and a polishing plate having the polishing cloth attached to a lower surface thereof and a connecting portion for attaching and detaching to and from the rotating shaft. And a polishing head having an automatic attachment / detachment mechanism that automatically attaches and detaches the polishing platen to and from the rotating shaft, and holds the polishing head capable of moving up and down and moving in a horizontal plane, A manipulator for moving the polishing head, a first platen table for mounting a new polishing platen for replacement, which is installed within a moving range of the polishing head, and a manipulator to be removed from the rotating shaft. A replacement portion having a second platen table for placing a MigakuJoban is characterized in that it comprises.

According to a preferred embodiment, the manipulator includes an arm for holding the polishing head and performing a revolving motion, and the first and second platen tables are pivoted through the center of the chuck platen. They are placed on the route. When replacing the polishing platen with the polishing cloth, the arm pivots to the first platen table, where the polishing platen is separated from the polishing head. Thereafter, the arm pivots to the second platen table, where a new polishing table is connected to the polishing head.

It is preferable that a position where dressing of the polishing pad is further performed is disposed on the turning path.
According to this, it is possible to automate a series of operations of polishing the wafer on the chuck plate, dressing the polishing pad, and replacing the polishing plate while rotating the arm.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a polishing head and a polishing apparatus according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a polishing apparatus according to the present embodiment. FIG. 2 is a plan view showing an arrangement of each part of the polishing apparatus 10. The polishing apparatus 10 includes a chuck platen 12 that rotates while holding the wafer 2, and a polishing platen 11 on which a polishing cloth 13 is mounted. The polishing table 13 is pressed against the wafer 2 to polish the wafer 2. A head 14, a manipulator 16 for holding the polishing head 14 and moving the same in the vertical and horizontal directions, and an exchange for exchanging the polishing cloth 13 which has become unsuitable for polishing together with the polishing platen 11. It has a unit 18. The chuck surface plate 12, the manipulator 16, and the exchange unit 18 are arranged on the upper surface of the frame 20 so as to maintain an appropriate positional relationship.

1. On the upper surface of the chuck platen 20, a cylindrical portion 2 for attaching the chuck platen 12 is provided in a part which is lowered by one step and falls.
1 is formed. A bearing 22 is built in the inner peripheral surface of the cylindrical portion 21 so as to support the rotating shaft 23 vertically, and the rotating shaft 23 of the chuck base 12 is rotatably supported by the bearing 22. . This allows
The chuck base 12 can rotate on a horizontal plane. Reference numeral 24 denotes a motor that drives the chuck base 12 to rotate.

A circular concave surface is formed on the upper surface of the chuck base 12, and this concave surface is a suction surface for holding the wafer 2. In this embodiment, the wafer 2
Is sucked in vacuum through the packing pad 26. A number of vacuum holes 27, 2
7,... Are opened. Also, the rotating shaft 23
Is formed with a through hole 28 for evacuation so as to penetrate along the axis thereof, and the vacuum holes 27, 27,... Of the chuck platen 12 branch from the through hole 28 and extend to the suction surface. It has become. The through hole 28 of the rotating shaft 23 is
It is connected to a through-hole 30 for evacuation, which passes through the rotor 29 of the motor 24 for driving the chuck base 12. A rotary joint 31 is attached to the distal end of the rotor 29, and a tube 32 connected to a vacuum source (not shown) is connected to the rotary joint 31.

2. Polishing Head Next, the polishing head 14 will be described. 33 is a cylindrical housing of the polishing head 14. A bearing 35 that rotatably supports the rotating shaft 34 of the polishing head 14 is housed inside the housing 33. A servomotor 36 as a drive source is mounted on the upper part of the housing 33, and the rotating shaft 34 is directly connected to the servomotor 36.

FIGS. 3 and 4 show that the polishing platen 11 is
1 shows an automatic attachment / detachment device 38 provided with a mechanism for automatically attaching / detaching.

The automatic attachment / detachment device 38 includes a master plate 40 forming a first connection portion attached to a flange portion at a lower end of the rotary shaft 34 and a tool plate 42 constituting a second connection portion attached to the polishing platen 11. It consists of two components. The inner diameter of the master plate 40 constitutes a cylinder 43. That is,
A piston 44 is provided concentrically with the inner diameter of the master plate 40.
Are slidably fitted. The cylinder chambers on both sides of the piston 44 are connected to the cylinder chamber 46a for connection with the rotary shaft 34 side.
The tool plate 42 side is a cylinder chamber 4 for separation.
6b.

The tip portion 4 having a reduced diameter of the piston 44
4a is configured such that the retainer plate 47 is inserted so that the tip enters the tool plate 42 side. The retainer plate 47 is provided with a cylinder chamber 46b for separation.
Is fixed to the end face of the master plate 40 so as to hermetically seal it. The short cylindrical portion 4 of the retainer plate 47
8 holds three steel balls 50 as connection elements for connecting the master plate 40 and the tool plate 42. The steel balls 50 are arranged symmetrically with respect to the center of the piston 44, and are held by the short cylindrical portion 48 so as to be movable in the radial direction.

On the other hand, the inner diameter of the tool plate 42
A ring-shaped steel ball receiver 52 is attached. The inner diameter of the steel ball receiving portion 52 is greatly enlarged via the tapered portion 51 so that the steel ball 50 can be engaged with the inner peripheral surface thereof. Further, a tapered portion 53 is also formed at the tip of the piston 44. The tapered portion 5 of the piston 44
3, as shown in FIG. 3B, the steel ball 50 abuts on the steel ball 50 and moves radially outward with the advance of the piston 44.
Abuts at an angle that can be pushed out.

The master plate 40 has a cylinder chamber 46.
connection air pressure port 54a for introducing air into
And a separation air pressure port 54b for introducing air into the cylinder chamber 46b. As shown in FIG. 4, a port 55 and a port 56 for a polishing liquid are formed in the master plate 40 and the tool plate 42 for sending the polishing liquid to the polishing platen 11. These polishing liquid ports 55 and 56 communicate when the master plate 40 and the tool plate 42 are connected, and form an inlet and an outlet of a passage through which the polishing liquid flows. In addition,
Reference numeral 57 denotes a positioning pin for stacking the master plate 40 and the tool plate 42 in phase.

The polishing platen 11 always has a tool plate 42
Used in the state where is attached. The polishing platen 11 has a diameter smaller than the diameter of the chuck platen 12 (in this embodiment, about １ ／ of the chuck platen 12).

3. Manipulator In FIG. 1, the manipulator 16 includes a column 60 erected on the frame 20 and an arm 61 horizontally mounted on the column 60. Arm 6
1 is rotatably mounted on a horizontal surface at the upper part of the column 60 via a bearing 62, and is driven by a motor 64 for rotation. The polishing head 14 includes a swing arm 61
Is held at the front end of the head through a guide 65 so as to be able to move up and down. Reference numeral 66 denotes an air cylinder connected to the polishing head 14. The air cylinder 66 raises and lowers the polishing head 14, and when the polishing head 14 is lowered, the polishing cloth 13 of the polishing platen 11 is moved to the chuck platen. 12 can be pressed against the wafer 2 with a predetermined surface pressure. Such a manipulator 16 is operated in a certain order by a sequencer (not shown). This sequencer controls the motors 24, 36, 64 according to a predetermined sequence program.

The air supply pipe for the desorption operation and the supply pipe for the abrasive supplied to the automatic desorption device 38 of the polishing head 14 are as follows:
It is piped through the inside of the column 60. Reference numeral 68a denotes an air supply pipe for connection, and 68b denotes an air supply pipe for disconnection. 69 is an abrasive supply pipe. Polishing head 1
In FIG. 4, since the polishing platen 11 itself rotates, the air supply pipes 68a and 68b and the abrasive supply pipe 69
Once connected. The rotary joint 70 is provided with a rotary shaft 3
4 is connected to a passage formed so as to penetrate through the rotary joint 70, and air for desorption operation is supplied from the rotary joint 70 to the rotary shaft 34.
3 through the connecting pipe 71 to the connecting pneumatic port 54a and the disconnecting pneumatic port 54b shown in FIG. In the same manner, for the abrasive, the rotary shaft 70
The abrasive passing through the internal passage of No. 4 is guided to the port 55 of the master plate 40 via the connection pipe 72, and further formed inside the polishing platen 11 via the connection pipe 73 from the port 56 of the tool plate 42. The polishing platen 11 is led out from the lower surface of the polishing platen 11 through a passage 74 that is formed.

4. Exchange Unit The exchange unit 18 is provided with two polishing bases A and a polishing base B in this embodiment. The polishing table bases A and B are respectively supported at predetermined heights. Of these, the polishing table base A is for mounting the polishing table 11 removed from the polishing head 14. The polishing table B is for placing a replacement polishing table 11a on which a new polishing cloth 13 is stuck. Reference numerals 84 and 85 indicate keys for phase matching.

As shown in FIG. 2, these polishing platen tables A and B are arranged on the turning path of the polishing head 14. That is, the centers of the polishing table bases A and B and the chuck table 12 are located at a distance corresponding to the turning radius from the center of rotation of the arm 61, and the turning of the arm 61 causes the polishing head 14 to move to the center of the chuck table 12. And moves along a turning path that passes through the centers of the polishing platen tables A and B together. Next, the operation of the present embodiment will be described in relation to the wafer polishing step. 5. 1. Polishing of Wafer In FIG. 1, while the wafer 2 to be polished is fixed on the upper surface of the chuck base 12 via a packing pad 26 by vacuum suction, the chuck base 12 is driven and rotated by a motor 24. . In the polishing head 14, the polishing table 11 is rotated in the same direction as the chuck table 12 by the servomotor 36. Then, the air cylinder 66 operates to lower the polishing head 14. The polishing of the wafer 2 is performed while flowing the polishing agent from the passage 74 of the polishing platen 11.
The polishing is performed while pressing the polishing cloth 13 of the polishing platen 11 against the wafer 2 at a predetermined surface pressure. During this polishing, the manipulator 16
The arm 61 performs a swinging motion, and reciprocates the polishing platen 11 a plurality of times within the range of the diameter of the wafer 2 to polish the entire surface of the wafer 2.

As soon as the polishing of the wafer 2 is completed, the rod of the air cylinder 66 retracts, and the polishing head 14 moves up. When the polishing platen 11 separates from the wafer 2, the servomotor 36 and the motor 24 stop, and the polishing platen 1
1. The chuck platen 12 stops rotating.

6. Dressing of Polishing Cloth 13 After polishing of the wafer 2 is completed, dressing of the polishing cloth 13 is performed next. In FIG. 2, the arm 61 pivots to a dressing position 90. The dressing device used here is preferably provided at a dressing position 90 on the turning path of the arm 61. As the dressing device, for example, a device provided with a mechanism for rotating while pressing a grindstone for dressing the polishing pad 13 is used. Also, dressing position 9
When the dressing device is not installed at 0, the dressing grindstone may be moved to the dressing position 90.

As soon as the dressing of the polishing pad 13 is completed,
The turning arm 61 turns again in a direction of the chuck base 12 and returns the polishing head 14 to a position above the chuck base 12. In order to process another wafer 2 again with the dressed polishing cloth 13, the same operation as described above is repeated.

7. Replacement of polishing platen When polishing and dressing are repeated with the same polishing cloth 13 in this way, the polishing cloth 13 is shaved and its thickness becomes thin, and it is not suitable for polishing the wafer 2. This determination is performed by, for example, time management, the total polishing time is measured, and if it exceeds a predetermined polishing time obtained empirically in advance, it is determined to be inappropriate.

In order to replace the polishing cloth 13 which has become unsuitable for processing together with the polishing platen 11, in FIG. It is moved to just above the table A.

By this turning operation, the polishing table 11 connected to the polishing head 14 is positioned such that the center of the polishing table 11 and the polishing table A are aligned. Then, in order to match the phase with the polishing table A, the servo motor 36 is rotated, and the key groove of the polishing table 11 is changed to the key 84 of the polishing table A.
Rotate to a rotation position suitable for. As soon as the phases are matched, the entire polishing head 14 is lowered to a position where the polishing table 11 is just placed on the polishing table A.

Next, with the polishing platen 11 placed on the polishing platen table A, as shown in FIG.
Is operated, and the polishing platen 11 is separated from the polishing head 14. FIG. 3A shows a state in which the master plate 40 and the tool plate 42 of the automatic attachment / detachment mechanism 38 are connected. Except when the polishing platen 11 is removed, in the master plate 40, air is supplied to the connection cylinder chamber 46a, and the piston 44 holds the advanced position. If the piston 44 is located at this position, the steel ball 50 engaged with the steel ball receiving portion 52 is restrained by the piston 44 so as not to move.
The tool plate 42 and the tool plate 42 are not separated.

After the polishing table 11 is seated on the polishing table A, an electromagnetic switching valve (not shown) is switched, and air is supplied to a separating cylinder chamber 46b as shown in FIG. The switching is performed so that the air in the connection cylinder chamber 46a is exhausted. Since the piston 44 retreats, the steel ball 50 that has been constrained by the piston 44 is in an unconstrained state in which it can move. The weight of the tool plate 42 and the polishing platen 11 is applied to the steel ball 50, and the tapered surface 51 of the steel ball receiving portion 52 moves the steel ball 50 inward in the radial direction. In this state, when the polishing head 14 is raised together with the arm 61, the tool plate 42 is naturally separated from the master plate 40 by its own weight, and the polishing platen 11 is separated from the polishing head 14 while leaving the polishing platen 11 on the polishing platen table A. Can be.

Next, the arm 61 is turned to the polishing table B, and the polishing head 14 is positioned at a concentric position immediately above the polishing table B. Then, by rotating the servo motor 36, the polishing platen 11 on the polishing table
The phase of the master plate 40 is adjusted. This phase adjustment is for aligning the holes of the master plate 40 with the positions of the positioning pins 57 of the tool plate 42 (see FIG. 4). When the phases are matched, the master plate 40 can be overlapped with the tool plate 42 by lowering the arm 61.

Thereafter, as shown in FIG. 3A, air is supplied to the cylinder chamber 46a for connection, and the piston 44 is advanced. The piston 44 engages the steel ball 50 with the steel ball receiving portion 52 and restrains the steel ball 50 from moving. Therefore, the master plate 40 and the tool plate 42 are connected to each other so that the polishing pad 13 on which the new polishing pad 13 is attached is polished. Surface plate 11
a can be attached to the polishing head 14.

After the polishing cloth 13 is replaced together with the polishing platen 11 in this manner, the arm 61 is moved up and pivots to the chuck platen 12, and the wafer 2 is polished again.

As described above, a series of steps of polishing the wafer 2, dressing the polishing pad 13, and replacing the polishing platen 11 can be performed smoothly and automatically without stopping the polishing apparatus. In particular, the polishing pad 13 is
Since each one can be automatically replaced, it is possible to eliminate the idle time for replacing the polishing cloth as in the related art, thereby achieving a great improvement in processing efficiency.

Although the polishing head and the polishing apparatus according to the present invention have been described with reference to the preferred embodiments, the polishing head 14 may be moved linearly instead of turning. In this case, the polishing head 14 is attached to the arm 61 via a linear movement mechanism.
The chuck table 12, the polishing table table A, and the polishing table table B are arranged such that their centers are on the same straight line. Further, the automatic attachment / detachment mechanism is not limited to the automatic attachment / detachment mechanism 38 of the present embodiment.

[0041]

As is apparent from the above description, according to the present invention, the polishing cloth can be automatically changed together with the polishing platen, so that it is not necessary to stop the machine for changing the polishing cloth. The productivity of wafer polishing can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a polishing apparatus according to the present invention.

FIG. 2 is a plan view showing the arrangement of a polishing head, a chuck surface plate, and a surface plate table in the polishing device of FIG. 1;

FIG. 3 is a diagram showing an operation of an automatic attachment / detachment mechanism provided in the polishing head according to the embodiment of the present invention.

FIG. 4 is an exploded view of the automatic attaching / detaching mechanism.

[Explanation of symbols]

 2 Wafer 10 Polishing device 11 Polishing surface plate 12 Chuck surface plate 13 Polishing cloth 14 Polishing head 16 Manipulator 18 Replacement unit 20 Frame 23 Rotating shaft 33 Housing 34 Rotating shaft 38 Automatic attaching / detaching mechanism 40 Master plate (first connecting member) 42 Tool plate (Second connecting member) 44 Piston 50 Steel ball 52 Steel ball receiver 61 Arm

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/304 622 H01L 21/304 622M

Claims (5)

[Claims] 1. A polishing head for pressing a polishing cloth against a wafer while rotating the polishing cloth in the same direction as the wafer, comprising: a rotating shaft rotatably supported in a housing and connected to a driving motor; A polishing platen attached to the lower surface and having a connecting portion for attaching and detaching to and from the rotating shaft; and an automatic attaching / detaching mechanism for automatically attaching and detaching the polishing platen to and from the rotating shaft. A polishing head, characterized in that: 2. The automatic attachment / detachment mechanism, wherein: a first connection member fixed to the rotation shaft; and a detachable connection with the first connection member so that torque is transmitted from the rotation shaft. A second connecting member that constitutes the connecting portion, a connecting element that connects the first connecting member and the second connecting member, and a connecting element that is provided at an inner diameter portion of the second connecting member so that the connecting element can be detached. A receiving portion, which is provided so as to be able to reciprocate by a working fluid supplied through the rotating shaft inside the first connecting member, and restrains the connecting element to a receiving portion of the second connecting member at an advanced position. A piston that engages in a non-constraining manner only when retracted,
The polishing head according to claim 1, comprising: 3. A polishing apparatus for rotating a polishing cloth in the same direction as a wafer rotating on a surface plate and polishing the wafer with the polishing cloth while supplying an abrasive, comprising: a chuck surface plate for holding and rotating the wafer; A rotating shaft rotatably supported in the housing and connected to a drive motor; a polishing platen having the polishing cloth attached to a lower surface thereof and having a connecting portion for attaching and detaching to and from the rotating shaft; A polishing head comprising an automatic attachment / detachment mechanism that automatically attaches and detaches the polishing platen, and a manipulator that holds the polishing head so as to be able to move up and down and move in a horizontal plane, and moves the polishing head. A first platen table for placing a new polishing platen for replacement, which is installed within a movement range of the polishing head, and a second platen for placing a polishing platen to be removed from the rotary shaft. 2 A polishing unit, comprising: an exchange unit having a base platen. 4. The manipulator includes an arm that holds the polishing head and performs a swiveling motion, wherein the first and second platen holders are arranged on a swirl path passing through the center of the chuck platen. The polishing apparatus according to claim 3, wherein 5. The polishing apparatus according to claim 4, wherein a position where dressing of the polishing pad is further performed is arranged on the turning path.