JPH09254020A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an occupied area of a dresser and obtain stable polishing performance, in a polishing device polishing a semiconductor wafer or the like. SOLUTION: A dressing tool of grinding tool 36 or the like for dressing a polishing cloth 12a secured onto a surface 12 is provided around a wafer 16 in a tool wafer holding part 30 dressing of the polishing cloth 12a is performed in parallel to polishing of the wafer 16. As for the dressing tool, a tool of different kind may be provided so as arrange a brush around, for instance, the grinding tool 36. The wafer 16 and the dressing tool may be mutually independently rotated and driven, a dressing tool of different kind may be mutually independently rotated and driven. Further, the holding part 30 may be swiveled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for polishing an object to be polished such as a semiconductor wafer, and in particular, a dressing tool is provided around the wafer in a wafer holder to reduce the area occupied by the dresser and to stabilize the dresser. The polishing performance is obtained.

[0002]

2. Description of the Related Art Conventionally, as means for polishing a wafer for the purpose of flattening an interlayer insulating film formed on the surface of a semiconductor wafer, the wafer is pressed against a polishing cloth fixed on a rotating surface plate. There is known a polishing device that performs polishing by polishing.

In this type of polishing apparatus, as the number of processed wafers increases, the polishing cloth is clogged with the polishing agent or polishing debris. Further, the polishing cloth may be deformed or worn by the rotation of the wafer or the load from the wafer side. As a result, deterioration of polishing performance such as a decrease in polishing rate and damage or contamination of the wafer occur.

In order to deal with such a situation, it is known to add a dressing function to a polishing device to regenerate a clogged polishing cloth (for example, Japanese Patent Laid-Open No. 4-364).
730, JP-A-7-254578, etc.).

10 to 17 show an example of a conventional polishing process using a polishing apparatus having a dressing function. The main body 10 of the polishing apparatus is provided with a surface plate 12 having a polishing cloth adhered to the surface thereof, and a wafer receiver 14 near the surface plate 12. Further, as shown in FIG. 17, a dresser 24 held by a dresser holding portion 22 is movably provided on the main body 10, but FIGS.
The illustration is omitted for simplicity. As a dressing tool for the dresser 24, one of a wire brush, a resin brush, a diamond electrodeposition plate and the like is used.

As shown in FIG. 18, the wafer holding portion 18 holds the wafer 16 inside the guide 26 by vacuum suction or the like and is movable, and the wafer 16 is pressed against the polishing cloth on the surface plate 12. It is adapted to be rotationally driven via the rotary shaft 28.

In the process of FIG. 10, the wafer 16 to be processed is placed on the wafer receiver 14. Then, in the process of FIG. 11, the wafer holding unit 18 sucks and holds the wafer 16.

Next, in the process of FIG. 12, the wafer holder 1
8 is moved to the central portion of the surface plate 12 while holding the wafer. Then, in the process of FIG. 13, the wafer holding unit 18 is lowered and the wafer 16 is pressed against the polishing cloth on the rotating surface plate 12. While the polishing agent is being supplied onto the surface plate 12 from the dripping nozzle 20, the wafer 16 in the holding / pressure contact state is rotated to perform polishing.

After the polishing is completed, the wafer 16 is lifted from the surface plate 12 by the wafer holder 18 in the process shown in FIG. Then, in the process of FIG. 15, the wafer holding unit 18 is moved to the wafer receiver 14 in a wafer holding state, and the wafer 16 is removed from the wafer holding unit 18 on the wafer receiver 14 by suction release and application of water pressure.

Next, in the process of FIG. 16, the wafer holding unit 1
Return 8 to the initial position. Then, in the process of FIG. 17, after the dresser 24 is moved onto the surface plate 12 by the dresser holding portion 22, the dressing tool of the dresser 24 is pressed against the polishing cloth on the rotating surface plate 12 to rotate the dressing dressing. To do. In this case, the polishing cloth can be washed by supplying a cleaning liquid such as pure water from a pipe (not shown).

When the dressing is completed, the process returns to the step shown in FIG. 10 and the polishing process for the next wafer is performed in the same manner as described above.
Note that the dressing may be performed every time the polishing of a plurality of wafers is completed, instead of every time when the polishing of one wafer is completed.

[0012]

According to the above-mentioned conventional dressing means, the dresser 24 is mounted on the wafer holding portion 18.
Since they are provided independently of each other and are driven and rotated independently, the area occupied by the dresser 24 on the surface plate 12 is large, and it is difficult to provide a plurality of wafer holding portions 18, and the dresser 24 is also provided. Therefore, a mechanism for holding, rotating, moving, etc. is required, and the structure becomes complicated.

Further, in the above-mentioned conventional dressing means, since the dressing process is performed separately from the polishing process,
The polishing performance is not stable and the throughput is lowered.

Generally, the following (a)-
Performance such as (d) is required.

(A) Scraping out or grinding the clogged portion of the polishing cloth (grinding property) (b) Removing foreign matter on the polishing cloth (surface cleaning property) (c) Permanent deformation (pushing in) with an elastic polishing cloth, etc. Properties) (d) fluff alignment (trajectory alignment) with a fibrous polishing cloth, etc. Conventionally, various dressing tools have been proposed. However, at present, one type of dressing tool
There is no product that satisfies all the performance requirements of (d). Therefore, the conventional dressing means described above has a disadvantage that any one of the performances is unsatisfactory.

For example, in the case where a diamond electrodeposition plate having a large grindability is used as a dressing tool,
Polishing cloth cutting debris and fallen diamond grains remain on the polishing cloth, and adversely affect the wafer such as damage and contamination. Further, in the case of using a dressing tool having no cleaning property, the abrasive contaminated by the dresser is supplied to the object to be polished.

An object of the present invention is to provide a novel polishing apparatus capable of reducing the area occupied by the dresser and obtaining stable polishing performance.

[0018]

A polishing apparatus according to the present invention is a surface plate having a polishing cloth adhered to a plate surface, which is rotationally driven, and holding means having a holding portion for holding an object to be polished. The polishing apparatus is provided with: controlling the holding unit so as to press-contact the polishing cloth while rotating an object to be held during rotation of the surface plate, wherein the holding unit is It is characterized in that a dressing tool is provided around a portion for holding the object to be polished, and the dressing is performed in parallel with the polishing.

According to the structure of the present invention, since the dressing tool is provided around the portion for holding the wafer in the holding portion for holding the wafer as the object to be polished, the dresser is provided independently of the wafer holding portion. Therefore, the area occupied by the dresser on the surface plate can be reduced, and the mechanism for holding, rotating, moving, etc. for the dressing tool can be shared with the wafer holding unit. Therefore, the structure can be simplified, and it becomes easy to provide a plurality of wafer holding portions on the surface plate.

Since the polishing cloth is dressed in parallel with the polishing of the wafer, stable polishing performance can be obtained and throughput can be improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a polishing apparatus according to the present invention, and FIG. 2 shows a state of wafer polishing by the apparatus shown in FIG.

As shown in FIG. 2, the main body 10 is provided with a surface plate 12 having a polishing cloth 12a fixed to the surface thereof. The surface plate 12 is rotationally driven by a motor or the like (not shown).
A wafer receiver 14 for mounting a wafer as an object to be polished is provided near the surface plate 12 in the main body 10.

The tool / wafer holder 30 is shown in FIGS.
As described above with reference to 8, the guide 3 is attached by vacuum suction or the like.
4, the wafer 16 is held and movable inside, and as shown in FIG. 2, the wafer 16 is rotationally driven via a rotary shaft 38 in a state where the wafer 16 is pressed against the surface plate 12.

In the tool / wafer holding unit 30, a grinding tool 36 is provided in a ring shape around the portion holding the wafer 16 (outside the guide 34). Grinding tool 3
As 6, a diamond electrodeposition plate or the like can be used. Instead of the grinding tool 36, a brush according to the purpose,
Other dressing tools such as ceramic plates may be provided.

In the tool / wafer holding portion 30, a ring-shaped groove S opening to the upper surface of the holding portion 30 is provided in a portion between the guide 34 and the grinding tool 36, and the groove S is provided.
A large number of holes R that communicate with each other and penetrate to the bottom surface of the holding portion 30 are provided in a ring shape. The polishing agent P supplied from the dropping nozzle 40 is supplied to the wafer 16 through the groove S and the hole R without being hindered by the dressing tool such as the grinding tool 36, so that stable polishing can be performed.

The main body 10 is provided with a discharge portion 32 that surrounds the surface plate 12 and extends downward. The grinding dust is directed outward by centrifugal force, falls from the surface plate 12 to the discharge portion 32, and is removed. In addition, the used polishing agent is also used for the discharging section 3.
It is discharged via 2.

In the polishing process, the tool / wafer holder 30 transfers the wafer 16 from the wafer receiver 14 onto the surface plate 12 in the same manner as described with reference to FIGS.
While holding the wafer 16 at 0, while rotating the wafer 16, the wafer 16 is pressed against the polishing cloth 12a on the surface plate 12 to perform polishing. During polishing, as shown in FIG. 2, the polishing agent P is supplied from the dropping nozzle 40 to the wafer 16 and the polishing cloth 12a through the groove S and the hole R. Further, during the polishing, the grinding tool 36 is rotated and brought into pressure contact with the polishing cloth 12a, so that the polishing cloth 12a is subjected to a dressing treatment with grindability.

When the polishing is completed, the wafer 16 is returned to the wafer receiver 14 and the wafer 16 is removed from the tool / wafer holding unit 30 and the holding unit 30 is returned to the initial position as described with reference to FIGS.

According to the above polishing apparatus, the area occupied by the dresser on the surface plate 12 is reduced as compared with the conventional apparatus shown in FIG. Further, since the mechanism for holding, rotating, moving, etc. of the dresser is shared with the wafer holder, the structure is simple. Further, since the polishing cloth is dressed simultaneously with the polishing of the wafer, stable polishing performance can be obtained, and the independent dressing step as shown in FIG. 17 is not required, thus improving the throughput.

FIG. 3 shows a modified example of the tool / wafer holding portion. Similar parts to those in FIG. 2 are designated by similar reference numerals, and detailed description thereof will be omitted.

A feature of the tool / wafer holding unit 30 of FIG. 3 is that a brush 37 is provided in a ring shape at a portion between the grinding tool 36 and the hole R on the bottom surface of the holding unit 30. In this structure, the outer polishing tool 36 is used to polish the polishing cloth 12a.
It is intended to grind the clogged portion of No. 1 and to scrape the grinding dust to the outside by the inner brush 37 so that the grinding dust does not reach the wafer 16.

Since the groove S and the hole R are provided inside the brush 37, the polishing agent P is supplied from the dropping nozzle 40 to the wafer 16 through the groove S and the hole R without being hindered by the grinding tool 36 and the brush 37. be able to.

In the example shown in FIG. 3, different types of dressing tools are used, which are grindable (grinding tool 36) and surface cleaning (brush 37), but grindable and pushable (for example, It may be a combination with an alumina ceramic plate), a combination of a pushable type and a surface cleaning type, etc., and may be selected according to the purpose.

FIG. 4 shows a tool / wafer holding portion according to still another embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted.

A feature of the tool / wafer holder 30 of FIG. 4 is that the tool holder 30b provided with a grinder 36 is provided.
Is configured to be rotationally driven independently of the wafer holding unit 30a that holds the wafer 16. That is, the grinding tool 36 is fixed to the bottom surface of the tool holding portion 30b provided so as to cover the wafer holding portion 30a, and the holding portion 30b is coaxial with the outside of the rotary shaft 38a that rotationally drives the holding portion 30a. It is rotationally driven via a rotary shaft 38b arranged at. The holding portion 30b is provided with a groove Sb in a ring shape corresponding to the groove S provided on the holding portion 30a, and the wafer 16 is provided from the dropping nozzle 40 through the grooves Sb, S and the hole R.
The polishing agent P can be supplied to.

According to the configuration of FIG. 4, the grinding tool 36 can be dressed at an optimum rotation speed. In the example of FIG. 4, the dressing tool is rotationally driven independently of the wafer holding unit in the configuration of FIG. 2, but in the configuration of FIG. The tools (36, 37) can be rotationally driven independently of the wafer holder.

FIG. 5 shows a modification of the tool / wafer holding portion. The same parts as those in FIGS. 3 and 4 are designated by the same reference numerals and detailed description thereof will be omitted.

A feature of the tool / wafer holding unit 30 of FIG. 5 is that different kinds of dressing tools are rotationally driven independently of each other. That is, the brush 37 is provided in a ring shape on the outside of the hole R in the wafer holder 30a, and is rotationally driven together with the holder 30a by the rotary shaft 38a, and the grinding tool 36 is rotated in the same manner as described in FIG. Are driven to rotate together with the tool holder 30b.

According to the configuration of FIG. 5, the grinding tool 36 can be dressed at an optimum rotation speed. Also,
In the configuration of FIG. 5, the brush 37 may be driven to rotate independently of the grinding tool 36 and the wafer holder 30a. In this way, the brush 37 can be dressed at an optimum rotation speed.

FIG. 6 shows a polishing apparatus according to still another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and detailed description thereof will be omitted.

A feature of the apparatus shown in FIG. 6 is that the tool / wafer holding unit 30 is rotated and rocked. As an example, a support / guide member 33 that supports and guides the movable portion 31 is provided on the upper portion of the main body 10, the tool / wafer holding portion 30 is attached to the movable portion 31, and the movable portion is driven by a driving means such as a cylinder (not shown). 31
Is reciprocally driven in the directions of arrows A and A '. The tool / wafer holder 30 may be of any type described above with reference to FIGS.

According to the structure of FIG. 6, the dressing uniformity in the platen surface of the surface plate 12 can be further improved as compared with that of FIG. Further, the polishing efficiency is also improved as compared with that of FIG.

FIG. 7 shows a polishing / dressing portion according to still another embodiment of the present invention. The feature of the embodiment shown in FIG. 7 lies in that three tool / wafer holding units 30A to 30A
30C is arranged, and these holding portions 30A to 30 are arranged.
The configuration is such that C is rotationally driven in the direction of the arrow via the rotary shafts 38A to 38C, respectively. Holding parts 30A to 3
As 0C, any of the formats described above with reference to FIGS. 2 to 5 may be used.

According to the configuration of FIG. 7, the throughput is as shown in FIG.
Approximately 3 times better than the ones. The number of tool / wafer holders to be installed is not limited to three, but may be any desired number.

FIG. 8 shows a modification of the polishing / dressing portion. The same parts as those in FIG. 7 are designated by the same reference numerals, and detailed description thereof will be omitted. In this example, the rotary shafts 38A, 3
By independently swinging 8B and 38C in the directions of arrows a, a ', b, b'and c, c', respectively,
The wafer holders 30A, 30B, and 30C are configured to swing independently of each other.

FIG. 9 shows another modification of the polishing / dressing portion. The same parts as those in FIG. 7 are designated by the same reference numerals and detailed description thereof will be omitted. In this example, the rotary shaft 38A
38A to 38C are provided, and the tool / wafer holders 30A to 30C are interlocked with each other by swinging the connecting portion 42 in the directions of arrows S and S '.

According to the configurations of FIGS. 8 and 9, in addition to the effect of improving the throughput, the effect of improving the uniformity of dressing and improving the polishing efficiency as in the polishing / dressing portion described in FIG. can get.

The present invention is not limited to the above-described embodiment, but can be implemented in various modified forms. For example, in the embodiment shown in FIG. 4 or 5, the rotating shaft 38b connected to the grinding tool 36 can be moved up and down, and the grinding tool 36 can be lowered at any time to add a dressing having grindability. Good.

[0049]

As described above, according to the present invention, since the dressing tool is provided around the wafer in the wafer holding portion and the dressing is performed in parallel with the polishing, (a) the area occupied by the dresser is reduced. Reduction, (b) simplification of dressing mechanism, (c) stabilization of polishing performance,
(D) The effect of improving the throughput can be obtained.

Further, when the tool / wafer holder is swung while being rotated, the dressing uniformity is improved and the polishing efficiency is improved.

Further, if the wafer holder and the dressing tool are driven to rotate independently of each other, or if the wafer holder and the dressing tool of one type and the dressing tool of another kind are driven to rotate independently of each other, fine dressing is achieved. The effect of being able to control is also obtained.

Further, if a plurality of wafer holders are provided for one surface plate and a dressing tool is provided for each wafer holder to perform dressing in parallel with polishing, the throughput can be greatly improved. You can also get the effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing a polishing apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing a tool / wafer holding portion of the apparatus of FIG.

FIG. 3 is a sectional view showing a modification of the tool / wafer holding unit.

FIG. 4 is a sectional view showing a tool / wafer holder according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a modified example of the tool / wafer holding unit.

FIG. 6 is a perspective view showing a polishing apparatus according to still another embodiment of the present invention.

FIG. 7 is a perspective view showing a polishing / dressing portion according to still another embodiment of the present invention.

FIG. 8 is a perspective view showing a modified example of a polishing / dressing portion.

FIG. 9 is a perspective view showing another modification of the polishing / dressing portion.

FIG. 10 is a side view showing a wafer placing step in a conventional polishing process.

11 is a side view showing a wafer holding step following the step of FIG.

12 is a side view showing a wafer moving process following the process of FIG. 11. FIG.

FIG. 13 is a side view showing a wafer lowering and wafer polishing step subsequent to the step of FIG.

FIG. 14 is a side view showing a wafer raising process following the process of FIG.

FIG. 15 is a side view showing a wafer moving process and a wafer removing process following the process of FIG.

16 is a side view showing a wafer holding part returning process following the process of FIG.

FIG. 17 is a side view showing a polishing cloth dressing step that follows the step of FIG.

FIG. 18 is a sectional view showing a conventional wafer holder. [Brief Description of Drawings] 10: body, 12: surface plate, 12a: polishing cloth, 14: wafer receiver, 16: wafer, 30, 30A to 30C: tool / wafer holding unit, 32: discharge unit, 34: guide , 36:
Grinding tool, 37: Brush, 38, 38A to 38C, 38
a, 38b: rotating shaft, 40: dropping nozzle.

Claims (7)

[Claims] 1. A surface plate having a polishing cloth adhered to the plate surface,
And a holding means having a holding portion for holding an object to be polished, which is rotationally driven,
A polishing apparatus comprising: a device for controlling the holding part so as to press-contact the polishing cloth while rotating the object to be held during rotation of the surface plate, wherein the object to be polished in the holding part. The polishing apparatus is characterized in that a dressing tool is provided around a portion for holding, and dressing is performed in parallel with polishing. 2. The polishing apparatus according to claim 1, wherein the holding unit is configured to swing while rotating the holding unit. 3. The polishing apparatus according to claim 1, wherein another dressing tool of a different type from the dressing tool is provided around a portion of the holding section where the dressing tool is provided. 4. The polishing apparatus according to claim 1, wherein the holding unit is configured to rotate and drive the wafer and the dressing tool independently of each other. 5. A configuration in which another dressing tool of a type different from that of the dressing tool is provided around a portion of the holding portion where the dressing tool is provided, and these different kinds of dressing tools are rotationally driven independently of each other. The polishing apparatus according to claim 1 or 2. 6. A surface plate having a polishing cloth adhered to the plate surface,
One that is rotationally driven and another holding unit that has a plurality of holding portions that respectively hold an object to be polished, and presses the polishing cloth while rotating the object to be held while the platen is rotating. A polishing apparatus having a control unit for each holding unit, wherein a dressing tool is provided around a portion for holding the object to be polished for each holding unit, and dressing is performed in parallel with polishing. A polishing device characterized by the above. 7. The polishing apparatus according to claim 6, wherein the holding unit is configured to swing the plurality of holding units independently or in conjunction with each other while rotating the respective holding units.