JP2002110593A - Method and apparatus for removing remaining film on wafer edge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for effectively removing a remaining film on a wafer edge. SOLUTION: In the method, while a polishing agent slurry is supplied from a slurry supply tube 12 to a wafer W, polishing pad cylinders 14 formed into a cylindrical shape are slid as brought into contact with a wafer edge E to remove a remaining film on the wafer edge. The polishing cylinders 14 are brought into contact with the wafer edge E to polish and remove a remaining film on the edge E, while the polishing agent is supplied, while an angle is varied between the longitudinal direction of axial line of the cylinders 14 and the wafer surface of the wafer W, while the cylinders 14 revolve on their longitudinal axial line in an arrow X direction and also revolve along the edge E in an arrow Y direction, and while the cylinders are brought into contact with the edge E. Two of the cylinders are provided, one 14A of which is brought into contact with a surface side of the edge E and the other 14B is with a rear side of the edge E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for removing a residual film from a wafer edge, and more particularly to a method and an apparatus for reliably and almost completely removing a residual film from a wafer edge. .

[0002]

2. Description of the Related Art When a semiconductor device is manufactured by forming an integrated circuit on a wafer, the semiconductor device is formed at the center of a chip, which is a chip forming area, and has a wafer edge portion (wafer peripheral portion) from the center of the wafer to the outer edge of the wafer. ) Is a non-chip forming area, which is a part that is finally discarded.
When an insulating film such as a SiO ₂ film or a wiring layer such as a polysilicon film is formed for forming a semiconductor device, the insulating film, the wiring layer, and the like are formed on the entire surface of the wafer. Then, in the chip formation region in the central portion of the wafer, although a predetermined process is performed on the formed film, the film formed on the wafer edge portion usually remains as a residual film without being processed. When the remaining film is left as it is, a film such as an insulating film is further formed on the remaining film, and becomes a laminated remaining film as shown in FIG. The laminated residual film is easily broken by an impact due to an external force or the like, becomes a large number of particles, and scatters in the chip forming region at the center of the wafer, hinders the subsequent process and lowers the product yield. When the generation of particles is remarkable, the particles adhere to the chip formation region in the middle part of the wafer in a pattern as shown in FIG. Therefore, conventionally, a residual film remaining on the wafer edge portion is removed by dry etching, wet etching, or the like. Etching for removing the remaining film at the wafer edge is generally referred to as edge etching.

[0003]

However, in the conventional edge etching to which the dry etching method or the wet etching method is applied, a film in a region extending from the front surface to the back surface of the wafer edge cannot be sufficiently removed. There is a problem that the film remains in an incomplete state. As a result, as shown in FIG. 7, the film formed in the next film forming process adheres to the remaining film remaining in the previous film forming process, and is sequentially laminated to form a laminated residual film. Become. When the laminated residual film is destroyed by impact or the like, it becomes particles and scatters at the center of the wafer, resulting in a reduction in product yield.

Accordingly, an object of the present invention is to provide a method and an apparatus for effectively removing a residual film at a wafer edge.

[0005]

The present inventor has proposed a chemical mechanical polishing method (Chemical Mechanical Polishing) for removing a residual film at a wafer edge portion.
With the idea of applying hanical polishing (CMP), we studied a method of polishing the edge of a wafer by combining an abrasive slurry and a puff (polishing pad), and came to invent the method of the present invention. .

In order to achieve the above object, based on the above findings, a method for removing a residual film at a wafer edge portion (hereinafter referred to as a first invention method) according to the present invention is performed while supplying an abrasive to a wafer. A method of removing a residual film remaining on a wafer edge portion by contacting and sliding a polishing pad cylinder formed by attaching a polishing pad to a circumferential surface of the cylinder body with a wafer edge portion. While changing the angle formed between the longitudinal axis of the polishing pad cylinder and the wafer surface of the wafer, while rotating the polishing pad cylinder about the longitudinal axis, and revolving along the wafer edge, the polishing pad cylinder is rotated. The method is characterized in that the film is brought into contact with the wafer edge, and the remaining film remaining on the wafer edge is polished and removed.

[0007] In the first invention method, the polishing pad cylinder is:
This is a broad concept including not only a polishing pad formed in a columnar shape but also a polishing pad cylinder having a polishing pad attached to a cylinder. The polishing pad is formed of the same material as the polishing pad used in conventional CMP. As the polishing agent, it is preferable to use a polishing slurry used in conventional CMP. In a preferred embodiment of the first invention method, the polishing pad cylinder is rotated and revolved with respect to the wafer edge, and is further moved up and down. Thereby, local wear of the polishing pad cylinder can be prevented. Also, instead of the revolution of the polishing pad cylinder,
During the contact with the polishing pad cylinder, rotate the wafer around a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface,
More preferably, the wafer and the polishing pad cylinder are brought into contact with each other while rotating in mutually opposite rotational directions. Thereby, the relative sliding speed between the wafer edge portion and the polishing pad columnar body is further increased, and the residual film removing effect is enhanced.

In another method for removing a residual film at a wafer edge portion according to the present invention (hereinafter referred to as a second invention method), a polishing agent is supplied to a wafer and a concave portion having the same contour as the outer contour of the wafer edge portion is provided. Then, a polishing pad having a concave surface as a polishing surface is brought into contact with and slid against a wafer edge portion to remove a residual film remaining on the wafer edge portion. The polishing pad is run along the wafer edge while the polishing pad is in contact with and slid with the wafer edge so as to fit into the recess, and the remaining film remaining on the wafer edge is polished and removed.

In a preferred embodiment of the method of the second invention, the wafer is rotated around a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface during the contact with the polishing pad, and more preferably the wafer is rotated. The rotation direction is opposite to the running direction of the polishing pad. Thereby, the relative sliding speed between the wafer edge portion and the polishing pad is further increased, and the residual film removing effect is enhanced.

[0010] An apparatus for removing a residual film on a wafer edge portion, which implements the first invention method, comprises bringing a polishing pad columnar body formed in a columnar shape into contact with and sliding on a wafer edge portion while supplying an abrasive to the wafer. This is a device for removing the residual film remaining on the wafer edge portion, and a mechanism for supplying a polishing agent to the wafer, and contacting the wafer edge portion while changing the angle formed between the longitudinal axis of the polishing pad cylindrical body and the wafer surface of the wafer. A mechanism for rotating the polishing pad and revolving along the wafer edge while rotating the polishing pad, and a mechanism for rotating the wafer around a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface. .

An apparatus for removing a residual film at a wafer edge, which implements the method of the second invention, has a concave portion having the same contour as the outer contour of the wafer edge portion while supplying an abrasive to the wafer. The polishing pad to contact the wafer edge,
An apparatus for removing a residual film remaining on a wafer edge by sliding, a mechanism for supplying an abrasive to a wafer, and a wafer edge part being brought into contact with a polishing pad by fitting a concave portion of a polishing pad into the wafer edge part. A mechanism for moving the polishing pad along the wafer edge,
A mechanism for rotating the wafer about a rotation axis passing through the center of the wafer in a direction orthogonal to the wafer surface.

In the above-described apparatus, when the wafer makes an elliptical rotation on the wafer stage, the angle between the longitudinal axis of the polishing pad cylinder and the wafer surface is changed while changing the angle between the wafer surface and the wafer in accordance with the elliptical rotation of the wafer. And a mechanism for rotating the polishing pad while contacting the surface. Also,
A mechanism is provided in which the concave portion of the polishing pad is fitted into the wafer edge portion in correspondence with the wafer elliptical rotation so that the wafer edge portion and the polishing pad are in contact with each other and the polishing pad travels along the wafer edge portion.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 of the Method for Removing the Residual Film at the Wafer Edge The embodiment of the present invention is an example of the embodiment according to the first invention method, and FIG. 1 is a schematic view for explaining the method of the embodiment. As shown in FIG. 1, the method of the present embodiment is configured such that a polishing slurry is supplied from a slurry supply pipe 12 to a wafer W while a polishing pad columnar body 14 is brought into contact with and slid on a wafer edge portion E, whereby a wafer edge This is a method of removing a residual film remaining in the portion E. The polishing pad cylinder 14 is
The polishing pad is attached to a circumferential surface of a cylindrical body.
In the present method, while changing the angle between the longitudinal axis of the polishing pad cylinder 14 and the wafer surface of the wafer W while supplying the abrasive slurry, the polishing pad cylinder 14 is moved in the direction of arrow X around the longitudinal axis. The polishing pad cylinder 14 is brought into contact with the wafer edge E while rotating, revolving in the direction of arrow Y along the wafer edge E, and further moving up and down in the direction of arrow Z with respect to the wafer edge E. The remaining film remaining on E is polished and removed.

In this embodiment, the polishing pad cylinder 14
There are two polishing pads, one of the polishing pad cylinders 14A contacts the front side of the wafer edge E, and the other polishing pad cylinder 14B contacts the back side of the wafer edge E. There are two slurry supply pipes 12, each of which moves in conjunction with the revolving movement of the polishing pad cylinders 14A, B, and supplies the abrasive slurry to the wafer W near the polishing pad cylinders 14A, B. . The angle formed between the longitudinal axes of the polishing pad cylinders 14A and 14B and the wafer surface of the wafer W varies from 45 ° to 90 ° as shown in FIG.
If the angle of the polishing pad cylinder 14 is changed to a substantially horizontal position close to the wafer surface, the wafer may be flawed. Therefore, the angle is changed in the range of 45 ° to 90 °. The polishing pad cylinder 14 is caused to reciprocate vertically in the Z direction in order to prevent not only the rotation and revolution of the polishing pad but also local wear of the polishing pad cylinder 14 itself.

An embodiment of a method for removing a residual film from a wafer edge portion
Example 2 The present embodiment is another example of the embodiment according to the first invention method, and FIG. 2 is a schematic diagram for explaining the method of the present embodiment. As shown in FIG.
Instead of revolving the polishing pad cylinder 14 along the wafer edge E, the wafer W is rotated in the direction of the arrow Y. Except for this, the method is the same as that of the first embodiment. The rotation direction Y of the wafer W is the same as the polishing pad cylinder 1
4 is opposite to the rotation direction X.

Embodiment of Method for Removing Residual Film at Wafer Edge
Example 3 The present embodiment is an example of the embodiment according to the second invention method, and FIG. 3 is a schematic diagram for explaining the method of the present embodiment. As shown in FIG. 3, the method according to the present embodiment is such that the polishing pad 24 is brought into contact with the wafer edge E while the polishing slurry is supplied from the slurry supply pipe 22 to the wafer W, so that the residue remaining at the wafer edge E is obtained. This is a method of removing the film. The polishing pad 24 has a concave portion having the same contour as the outer contour of the wafer edge portion E, and the concave surface is a polishing surface. In the method of the present embodiment, the polishing pad 24 is attached to the wafer edge portion E such that the concave portion of the polishing pad 24 is fitted into the wafer edge portion E under the supply of the abrasive slurry.
The polishing pad 24 is caused to travel in the direction of the arrow X along the wafer edge portion E while being in contact with. The depth of the concave portion of the polishing pad 24 is substantially the same as or slightly smaller than the width of the wafer edge portion E (the distance from the outer edge of the wafer to the chip formation region). In the present embodiment, the number of the polishing pads 24 is not always one, and as shown in FIG.
4A and 4B may be separated from each other.

Embodiment of Method for Removing Residual Film at Wafer Edge
Example 4 The present embodiment is another example of the embodiment according to the second invention method, and FIG. 4 is a schematic diagram for explaining the method of the present embodiment. As shown in FIG.
The method is the same as that of the third embodiment except that the polishing pad 24 is stopped and the wafer W is rotated in the direction of the arrow X instead of moving the polishing pad 24 along the wafer edge E.

Embodiment 1 of Residual Film Removal Apparatus The embodiment of the present invention is an example of a residual film removal apparatus at the wafer edge for implementing the first invention method. FIG. 5 shows the wafer edge of the present embodiment. It is a top view which shows the structure of a residual film removal apparatus. The residual film removing device 30 of the present embodiment contacts the polishing pad columnar body 34 with the wafer edge E while supplying the polishing slurry to the wafer W from the slurry supply pipe 32, and thereby the residual film remaining on the wafer edge E. This is a device for removing the film.

The residual film removing device 30 includes, in or near a polishing chamber 35, a slurry supply mechanism 36 for supplying an abrasive slurry to the wafer W from a slurry supply pipe 32, a longitudinal axis of a polishing pad cylinder 34, and a wafer W. A rotation mechanism 38 for rotating and revolving the polishing pad columnar body 34 while making contact with the wafer edge portion E while changing the angle formed with the wafer surface;
A mechanism (not shown) for rotating the wafer and a transfer arm 39 for loading and unloading the wafer W into and from the polishing chamber 35 are provided. The polishing pad cylinder 34 has a polishing pad attached to the circumferential surface of the cylinder. The slurry supply mechanism 36 has a slurry nozzle at the tip of the slurry supply pipe 32, and supplies the abrasive slurry onto the wafer W while changing the angle of the slurry nozzle. The residual film removing apparatus 30 is an apparatus capable of simultaneously performing residual film processing on two wafers W. For polishing the front and back surfaces of the wafer edge portions E of the respective wafers W, polishing pad cylinders 34 are provided, respectively.
It has.

Embodiment 2 of the Residual Film Removal Apparatus The embodiment of the present invention is an example of the apparatus for removing the residual film at the wafer edge for implementing the method of the second invention. FIG. 6 shows the apparatus of the embodiment. It is a top view which shows the structure of a residual film removal apparatus. The residual film removing device 40 according to the present embodiment removes a residual film remaining on the wafer edge portion E by bringing the polishing pad 44 into contact with the wafer edge portion E while supplying the abrasive slurry to the wafer W from the slurry supply pipe 42. It is a device to do. The polishing pad 44 has a concave portion having the same contour as the outer contour of the wafer edge portion E, and the concave surface is a polishing surface.

The residual film removing apparatus 40 is an apparatus capable of simultaneously performing residual film processing on two wafers W. In the or near the polishing chamber 46, an abrasive is applied to the wafer W from a slurry nozzle at the tip of a slurry supply pipe 42. A slurry supply mechanism 48 for supplying;
A traveling mechanism 50 for moving the polishing pad 44 along the wafer edge E by bringing the polishing pad 44 into contact with the wafer edge E such that the concave portion of the polishing pad 44 is fitted into the wafer edge E.
A mechanism (not shown) for rotating the wafer about a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface, a transfer arm 52 for loading / unloading the wafer W into / from the polishing chamber 46, and placing the wafer W at a predetermined location; It has. Slurry supply mechanism 48
Is provided with a slurry nozzle at the tip of the slurry supply pipe 42, and supplies the abrasive slurry onto the wafer W while changing the angle of the slurry nozzle.

[0022]

According to the first aspect of the present invention, the polishing pad cylinder is moved along the longitudinal axis while the angle between the longitudinal axis of the polishing pad cylinder and the wafer surface is changed while the abrasive is supplied. By bringing the polishing pad cylinder into contact with the wafer edge while rotating around and revolving along the wafer edge, the remaining film on the wafer edge can be reliably and almost completely polished and removed. According to the second invention method, the polishing pad is run along the wafer edge while the polishing pad is brought into contact with the wafer edge while the polishing pad is in contact with the wafer edge under the supply of the abrasive. In addition, the remaining film remaining on the wafer edge can be reliably and almost completely polished and removed. In addition, since the treatment can be performed in combination with the CMP process, and furthermore, it is a mechanical treatment,
Compared with dry etching, it is not necessary to use a dangerous gas or the like, which is safe. Therefore, by applying the first and second invention methods, the product yield of the semiconductor device can be improved. Further, the residual film removing apparatus according to the present invention realizes an optimal apparatus for performing the first and second invention methods.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a method for removing a residual film from a wafer edge portion according to a first embodiment.

FIG. 2 is a schematic diagram illustrating a method for removing a residual film from a wafer edge portion according to a second embodiment.

FIG. 3 is a schematic diagram illustrating a method for removing a residual film from a wafer edge portion according to a third embodiment.

FIG. 4 is a schematic diagram illustrating a method for removing a residual film from a wafer edge portion according to a fourth embodiment.

FIG. 5 is a plan view illustrating a configuration of a residual film removing device according to the first embodiment.

FIG. 6 is a plan view illustrating a configuration of a residual film removing device according to a second embodiment.

FIG. 7 is a schematic side view of the wafer showing a state where a residual film adheres to a wafer edge portion.

FIG. 8 is a plan view of the wafer showing a state where particles adhere to the wafer surface.

[Explanation of symbols]

12: slurry supply pipe, 14: polishing pad cylinder,
22 ... slurry supply pipe, 24 ... polishing pad, 30 ...
... Residual film removing apparatus of Embodiment 1, 32... Slurry supply pipe, 34... Polishing pad cylindrical body, 35.
... Slurry supply mechanism, 38 ... Rotation mechanism, 39 ... Transfer arm, 40 ... Remaining film removing device of the second embodiment, 42
... Slurry supply pipe, 44 polishing pad, 46 polishing chamber, 48 slurry supply mechanism, 50 traveling mechanism,
52 ... Transfer arm.

Claims (12)

[Claims] 1. A polishing pad is attached to a peripheral surface of a cylindrical body while an abrasive is supplied to the wafer. A polishing pad columnar body is brought into contact with and slid on a wafer edge, thereby removing a residual film remaining on the wafer edge. A method of removing, while supplying an abrasive, while changing the angle between the longitudinal axis of the polishing pad cylinder and the wafer surface of the wafer, while rotating the polishing pad cylinder about the longitudinal axis, and A method for removing a residual film at a wafer edge portion, wherein the polishing pad cylinder is brought into contact with the wafer edge portion while revolving along the wafer edge portion, and a residual film remaining at the wafer edge portion is polished and removed. 2. The method according to claim 1, wherein the polishing pad columnar body is rotated with respect to the wafer edge portion, and further reciprocated while moving up and down. 3. The method according to claim 2, wherein, instead of revolving the polishing pad cylinder, the wafer is rotated around a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface during contact with the polishing pad cylinder. Item 2. The method for removing a residual film from a wafer edge according to Item 1. 4. The method according to claim 3, wherein the wafer and the polishing pad are brought into contact with each other while rotating in mutually opposite rotational directions. 5. The polishing apparatus according to claim 1, wherein the front side of the wafer edge is polished with the first polishing pad column, and the back side of the wafer edge is polished with the second polishing pad column.
3. The method for removing a residual film at a wafer edge portion according to item 1. 6. A wafer edge is formed by contacting and sliding a polishing pad having a concave portion having the same contour as the outer contour of the wafer edge portion and having the concave surface as a polishing surface with the wafer edge portion while supplying an abrasive to the wafer. A method of removing a residual film remaining on the polishing pad, wherein the polishing pad is fitted to the wafer edge while the polishing pad is in contact with the wafer edge while sliding the polishing pad under the supply of the polishing agent. And removing the remaining film remaining on the wafer edge portion by polishing the remaining film on the wafer edge portion. 7. The method according to claim 6, wherein the wafer is rotated around a rotation axis passing through the center of the wafer in a direction orthogonal to the wafer surface during contact with the polishing pad. . 8. The method according to claim 7, wherein the rotation direction of the wafer is opposite to the running direction of the polishing pad. 9. A polishing pad cylinder formed in a cylindrical shape is brought into contact with a wafer edge portion while supplying an abrasive to the wafer.
An apparatus for removing a residual film remaining on a wafer edge portion by sliding, a mechanism for supplying an abrasive to a wafer, and changing an angle formed between a longitudinal axis of a polishing pad cylinder and a wafer surface of the wafer. A mechanism for rotating the polishing pad while contacting the wafer edge and revolving along the wafer edge, and a mechanism for rotating the wafer about a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface. An apparatus for removing a residual film. 10. A wafer edge is provided by supplying a polishing agent to a wafer and contacting and sliding a polishing pad having a concave portion having the same contour as the outer contour of the wafer edge portion and having the concave surface as a polishing surface to the wafer edge portion. A mechanism for supplying a polishing agent to a wafer, a method for fitting a concave portion of a polishing pad to a wafer edge portion, the wafer edge portion and the polishing pad being brought into contact with each other, and the polishing pad being brought into contact with the wafer edge portion. And a mechanism for rotating the wafer around a rotation axis passing through the center of the wafer in a direction perpendicular to the wafer surface. 11. An apparatus for removing a residual film remaining on a wafer edge by bringing a cylindrical polishing pad into contact with a wafer edge while supplying an abrasive to the wafer. An apparatus for removing a residual film, comprising: a mechanism for rotating a polishing pad while making contact with a wafer edge while changing an angle formed between a longitudinal axis of a polishing pad cylinder and a wafer surface of a wafer. 12. A wafer edge portion is formed by contacting and sliding a polishing pad having a concave portion having the same contour as the outer contour of the wafer edge portion and a polishing surface having the concave portion surface as a polishing surface while supplying an abrasive to the wafer. An apparatus for removing the residual film remaining on the wafer, wherein the wafer edge and the polishing pad are brought into contact with each other in such a manner that the concave portion of the polishing pad is fitted into the wafer edge corresponding to the wafer elliptical rotation, and the polishing pad is moved along the wafer edge. A residual film removing device comprising a mechanism for running.