JP3225181B2 - Polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polishing apparatus,
In particular, the present invention relates to a polishing apparatus used in a polishing process for finishing a wafer surface smoothly in a semiconductor device processing field.

[0002]

2. Description of the Related Art In recent years, chemical mechanical polishing, which is being considered for use in the manufacture of semiconductor devices, involves a relative rotational movement between a wafer and a polishing cloth while pressing the wafer against the polishing cloth at a constant pressure. This is a process of polishing while supplying and supplying a polishing liquid.

A polishing apparatus used for this type of chemical mechanical polishing holds a surface plate on which a polishing cloth is fixed using an adhesive such as a double-sided tape, and a semiconductor wafer which is a material to be polished. A polishing head, a polishing agent supply device for supplying a polishing material onto a polishing cloth, a loader device for temporarily mounting a wafer and attaching and detaching the wafer to and from the polishing head.

The polishing head presses the surface of the held wafer against the surface of the polishing pad on the surface plate while rotating, and moves in the radial direction of the surface plate. At this time, the polishing agent is supplied from the polishing agent supply device, and the wafer is polished.

In this type of polishing apparatus, as a method of mounting a wafer on the lower surface of a polishing head, a waxless pad method such as vacuum suction and water bonding is adopted for automation. In this case, in order to rotate the wafer integrally with the polishing head, the wafer must be firmly mounted, so a vacuum suction method is often adopted.In this vacuum suction method, during polishing, The wafer is always vacuum-suctioned.

[0006] Recently, with the progress of miniaturization of patterns, it has become particularly required to perform polishing of a wafer while maintaining a high degree of flatness. Therefore, it is indispensable to uniformly press the wafer adsorbed by the polishing head over the entire surface thereof against the polishing cloth on the surface plate.

Conventionally, a polishing head is generally provided with a mechanism for uniformly pressing a wafer. For example, a conventional technique is disclosed in Japanese Utility Model Laid-Open Publication No. 64-1626.
And Japanese Patent Application Laid-Open No. 4-201174.

[0008]

However, as disclosed in Japanese Utility Model Laid-Open Publication No. 64-16260, a polishing head incorporating an air cylinder for ensuring a high degree of flatness of a wafer is incorporated in the polishing head. In addition to the vacuum passage, a passage for supplying air to the air cylinder is required.

Since the polishing head during the polishing process is always in a rotating state, conventionally, two through-holes are provided on the rotating shaft of the polishing head, and these are used as a passage for vacuuming and pressing air. In addition, it is necessary to provide these systems with two systems of paths to the tip of the polishing head via a rotary joint for two channels to the tip of the polishing head, which complicates the structure of the polishing head and increases the number of rotating shafts more than necessary. There was a drawback that it became thicker.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide only a vacuum passage on the rotating shaft of the polishing head and omit the pressing passage. Another object of the present invention is to provide a polishing apparatus capable of simplifying the structure of a polishing head. It is another object of the present invention to provide a polishing apparatus capable of uniformly pressing a wafer against a polishing cloth over the entire surface thereof.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a platen on which a polishing cloth is adhered on the upper surface and which rotates, and a wafer which is held while rotating the sucked wafer. A polishing head that can be pressed against the polishing cloth on the board,
In a polishing apparatus having a loader device for temporarily mounting a wafer and mounting and removing the wafer with the polishing head, the polishing head has a rotating shaft, a top plate connected to the tip of the rotating shaft A top plate having a main body, a top plate mounted so as to rotate integrally with the top plate main body, a top surface having a wafer suction surface formed on a lower surface, and a piston having a pressing portion abutting on a center of the back surface of the top plate; A top plate pressing air cylinder concentrically incorporated into the plate body, an air passage for supplying air to the top plate pressing air cylinder is formed in the top plate body, and an outer surface of the top plate body is provided. Attach a joint with a check valve to the inlet opening to the, further, when the polishing head is moved on the loader device To, and is characterized in that it has disposed detachably air supply device connectable to said check valve attached fittings.

In the polishing apparatus according to the present invention, the air supply device is connected to an actuator so as to be able to move forward and backward, and supplies air in conjunction with a wafer suction operation of a polishing head on a loader device. It is characterized by the following.

Further, in the present invention, the tip of the pressing portion of the top plate pressing air cylinder is formed in a hemispherical shape, and a concave curved surface is formed on the back surface of the top plate in contact with the pressing portion. It is characterized by having.

According to the present invention, when the polishing head is stopped on the loader device to attract the wafer on the loader device, the air supply device is operated to advance toward the polishing head, and the top plate is moved. Is connected to the joint with check valve provided in

When the air supplied from the air supply device is filled into the top plate pressing air cylinder from the passage in the top plate, the air supply device is separated from the joint with the check valve of the polishing head, and the polishing head is , And move to just above the surface plate. During this time, the pressure of the filled air is maintained by the check valve of the joint with a check valve.

The polishing head on the surface plate presses the sucked wafer against the polishing cloth on the surface of the surface plate, and the air cylinder for pressing the top plate in the top ring main body is urged by the above-mentioned filled air. The piston pushes the central portion of the top plate to ensure a high degree of flatness of the wafer by polishing.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing apparatus embodying the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view showing the overall configuration of the polishing apparatus, and FIG. 2 is a plan view of the polishing apparatus. 1 and 2, reference numeral 10 denotes a base of the polishing apparatus, and reference numeral 11 denotes a surface plate for polishing the wafer 50. Reference numeral 12 denotes a loader device for attaching and detaching the wafer 50 to and from the polishing head 13. The wafer 50 is placed on the loader device 12 manually or by a robot. The polishing head 13 on which the wafer 50 is vacuum-adsorbed is
The arm 14 is configured to be driven by a turning motor 15 to turn between the surface plate 11 and the loader device 12 while holding the wafer 50 by suction.

The polishing head 13 is connected to a rotating shaft 16 as will be described later. The rotating shaft 16 is rotatably supported by an arm 14 via a bearing (not shown) and is rotated by a motor 17. The whole of the polishing head 13 and the rotating shaft 16 is connected to an air cylinder 18 for elevating and lowering the polishing head via a rotary joint 19. The wafer 50 sucked by the operation of the air cylinder 18 can be pressed against the polishing pad 20 adhered to the upper surface of the platen 11. The polishing cloth 20 is supplied with a polishing liquid from a polishing liquid supply device (not shown).

FIG. 3 is a sectional view showing the structure of the polishing head 13 in detail. The polishing head 13 includes a top plate main body 22 and a top plate 23, of which the top plate main body 22 is concentric with the tip of the rotating shaft 16 as self-aligning means. The top plate 23 is fixed to the top plate main body 22 using a fastening element such as a bolt.

The lower surface of the top plate 23 is
., And a plurality of vacuum holes 27 formed through the top plate 23 are opened on the suction surface of the top plate 23. These vacuum holes 27 communicate with vacuum passages 28 through a vacuum chamber 26 formed by a concave portion on the lower surface of the top plate body 22 and an upper surface of the top plate 23. . One end of a vacuum hose 31 is connected to the vacuum passage 29 through a joint 30, and the other end of the vacuum hose 31 is connected to the rotary shaft 16 through a joint 32 in a longitudinal direction. 33
Is to be connected to.

In this embodiment, between the rotation shaft 16 and the top plate body 22, the rotation transmission rods 34A, 34
B is provided so as to be abuttable, whereby the rotation of the rotating shaft 16 is transmitted to the top plate main body 22.

In the polishing head 13, an air cylinder 35 for pressing the top plate is provided in addition to the above-described vacuum suction means. The air cylinder 35 for pressing the top plate is concentrically incorporated into the top plate body 22, and the tip of the pressing piston 36 of the air cylinder 35 is attached to the top plate body 22.
A hemispherical pressing portion 39 is formed at a tip protruding downward from the lower surface of the lower surface. The pressing portion 39 is provided on the top plate 23.
It just comes in contact with the center of the back of the camera.

Compressed air is supplied from a passage 38 to a cylinder chamber 37 of an air cylinder 35 containing such a pressing piston 36. The passage 38 is formed so as to extend to the outer surface of the top plate body 22, and a joint 40 in which a check valve is pre-installed is attached to a passage inlet opening to the outer surface of the top plate body 22. Have been.

FIG. 1 shows an air supply device 42 provided with connection means (not shown) such as a quick joint so as to be detachably connected to the joint 40 with a check valve. The air supply device 42 is arranged near the loader device 12, and is connected to an actuator such as an air cylinder (not shown) to move toward and away from the loader device 12 so as to be able to move forward and backward. The air supply device 42
Is supplied with air pressurized to a predetermined pressure from an air supply pipe via a stop valve 43.

The present polishing apparatus is configured as described above. Next, the operation thereof will be described.

First, when the polishing head 13 moves to just above the loader device 12 with the turning of the arm 14, the polishing head 13 moves the air cylinder 18
Operates, and the suction surface on the lower surface of the top plate 23 comes into contact with the wafer 50 set on the loader device 12. At this time, a vacuum pump (not shown) is started, and the wafer 50 is attracted to the top plate 23 of the polishing head 13.

At the same time as the suction operation, the air supply device 42 moves forward with respect to the polishing head 13 stopped on the loader device 12. When the air supply device 42 is connected to a joint 40 with a check valve attached to the outer peripheral surface of the top plate body 22 of the polishing head 13, compressed air controlled to a predetermined pressure is passed through the passage 38 to the cylinder chamber 37. Fill. Thereafter, although the air supply device 42 is retracted, even after the air supply device 42 is detached from the joint 40 with a check valve, the pressure of the compressed air filled in the cylinder chamber 37 is maintained by the operation of the check valve controlled internally. Has become.

Next, when the polishing head 13 is turned to a position directly above the platen 11, the air cylinder 18 for raising and lowering the polishing head is operated, and the wafer 50 sucked and held on the top plate 22 of the polishing head 13 is fixed. Polishing cloth 2 on board 11
Press to zero. At this time, the wafer 50 is pressed against the polishing pad 20 by the centering action of the self-centering bearing 24. The platen 11 and the polishing head 13 start rotating. A polishing agent of an aqueous alkaline colloidal silica solution is supplied from a polishing agent supply device (not shown) to perform polishing.

While the wafer 50 is being polished on the surface plate 11, the center of the top plate 22 is constantly pressed by the pressing portion 39 of the pressing piston 36.
6 prevents the center portion from being dented and the self-aligning bearing 24 from pressing the outer periphery of the top plate 22 to prevent the center portion from being deformed in the same manner as described above. Over the polishing cloth 20. Also, preferably, the pressing portion 3
6 is preferably formed in the center of the back surface of the top plate 23 so as to correspond to the hemispherical shape of the top plate 6. In this case, the pressing portion 39, the concave curved surface 44, and the wafer 50 are formed.
Is preferably coaxial with each other.

[0030]

As is apparent from the above description, according to the first and second aspects of the present invention, the air supply device for supplying air to the top plate pressing air cylinder for pressing the top plate is provided on the top plate. Since the connection can be made when the robot is stopped on the loader device by using the mounted joint with check valve, the rotating shaft of the polishing head is one of the two systems of the vacuum suction passage and the pressurization passage. It is possible to omit the pressure passage and make it a single system only for the vacuum passage,
In addition, the structure of the top plate of the polishing head can be greatly simplified.

[Brief description of the drawings]

FIG. 1 is a side view showing the overall configuration of a polishing apparatus embodying the present invention.

FIG. 2 is a plan view of the polishing apparatus of FIG.

FIG. 3 is a sectional view showing a configuration of a polishing head of the polishing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Base 11 Surface plate 12 Loader device 13 Polishing head 14 Arm 15 Rotating motor 16 Rotating shaft 18 Polishing head raising / lowering air cylinder 20 Polishing cloth 22 Top plate main body 23 Top plate 24 Self-aligning bearing 26 Vacuum chamber 27 Vacuum hole 34A, 34B Rotation transmission rod 36 Pressing piston 35 Air cylinder for pressing top plate 37 Cylinder chamber 39 Pressing part 40 Joint with check valve 42 Air supply device

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-40231 (JP, A) JP-A-5-69314 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/304 622 B24B 37/04

Claims (3)

(57) [Claims] A polishing table which is attached to the upper surface thereof and rotates; a polishing head capable of pressing the wafer against the polishing cloth on the surface plate while rotating the wafer; A polishing apparatus having a loader device for mounting and removing a wafer on and from the polishing head, wherein the polishing head comprises: a rotating shaft; a top plate body connected to a tip of the rotating shaft; A top plate mounted so as to rotate integrally with the plate body and having a suction surface for a wafer formed on a lower surface; and a piston having a pressing portion abutting on the center of the back surface of the top plate, and concentric with the top plate body. And an air passage for supplying air to the top plate pressing air cylinder. A joint with a check valve is attached to an inlet formed on the outer surface of the top plate body and formed on the loader body, and further, when the polishing head is moved onto the loader device, the joint with the check valve is provided. A polishing apparatus, further comprising an air supply device detachably connected to the polishing apparatus. 2. The air supply device according to claim 1, wherein said air supply device is connected to an actuator so as to be able to move forward and backward, and supplies air in conjunction with a wafer suction operation of a polishing head on a loader device. The polishing apparatus according to claim 1. 3. The method according to claim 3, wherein a tip of the pressing portion of the top plate pressing air cylinder is formed in a hemispherical shape, and a concave curved surface is formed on a back surface of the top plate in contact with the tip of the pressing portion. The polishing apparatus according to claim 1, wherein: