KR100675092B1 - Polishing apparatus for reclaimed wafer and polishing method thereof - Google Patents

Abstract

The present invention relates to a polishing apparatus for recycled wafers and a polishing method thereof. In the polishing apparatus for reclaimed wafers according to the present invention, there is provided a polishing apparatus for reclaimed wafers, comprising: a surface plate having a polishing portion which rotates about a predetermined axis of rotation and the surface of the wafer is in contact polishing; The wafer holder supporting the wafer has a holder detachable part detachable, and is mounted on the polishing part and rotates according to the rotation of the surface plate. The slurry state contains silica (SiO ₂ ), an aqueous solution, and diamond powder supplied between the polishing part and the wafer. A plurality of blocks for polishing the wafer with abrasives; And a block head disposed on the upper portion of the surface plate so that the block can be detachably coupled thereto. As a result, a diamond mechanical polishing (DMP) process and a chemical-mechanical polishing (CMP) process can be performed simultaneously in a single device, thereby reducing wafer regeneration polishing, shortening manufacturing time, reducing manufacturing cost, and improving productivity. have.

Description

Polishing device for recycled wafer and its polishing method {POLISHING APPARATUS FOR RECLAIMED WAFER AND POLISHING METHOD THEREOF}

1 is a cross-sectional view of a main portion of a polishing device for a recycled wafer according to the present invention,

2 is a plan view of the block head of FIG.

Figure 3 is a view showing the rotational direction of the surface plate and the block during the polishing operation of the polishing apparatus for reclaimed wafer according to the present invention.

* Explanation of symbols for the main parts of the drawings

3: sapphire wafer 5: wafer polishing apparatus

10: surface plate 13: polishing part

20: block 21: holder detachable part

23: wafer holder 25: injection nozzle ball

30: block head 31: flow hole

33: abrasive supply path 40: abrasive supply unit

41: reservoir 45: pump

51: Stirrer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for regenerated wafers and a polishing method thereof, and more particularly, to a regenerated wafer polishing apparatus and a method for polishing the same, which improve the regeneration polishing process of a sapphire wafer having a defective gallium nitride layer.

In general, the polishing process of the sapphire wafer on which the sapphire film is formed includes a diamond mechanical polishing (DMP) process for removing a gallium nitride layer of the sapphire wafer, and a chemico-mechanical polishing (CMP) for imparting epitaxial grade sapphire surface properties. It is divided into processes.

On the other hand, D.M.P. for removing the gallium nitride layer of the wafer. In the process, the surface of the wafer is polished by supplying a liquid diamond slurry in which an aqueous solution is mixed into a diamond powder having a size of 1 to 2 µm as an abrasive on a surface plate made of copper or tin.

In the CMP process, a slurry mainly composed of silica (SiO ₂ ) material is supplied as an abrasive on a surface plate on which a polyurethane resin is foamed or impregnated with an adsorption pad to polish the surface of the wafer from which the gallium nitride layer is removed.

By the way, conventionally, in order to reproduce a sapphire wafer having a defective gallium nitride layer, D.M.P. Process and C.M.P. Since the processes must be performed sequentially in separate polishing apparatuses, there is a problem that not only the manufacturing cost increases but also the manufacturing time increases, resulting in a decrease in productivity.

In addition, D.M.P. When the sapphire wafer is polished in the process, the copper or tin is peeled off the surface by the diamond contained in the liquid diamond slurry, and the copper or tin adheres to the diamond particles. In the case of recycling the liquid diamond slurry used in the process, there is a risk that scratches may occur on the surface of the wafer to be polished, there is a problem that can not recycle expensive abrasives.

Accordingly, an object of the present invention is to simultaneously perform a diamond mechanical polishing (DMP) process and a chemical-mechanical polishing (CMP) process in a single device, thereby reducing wafer regeneration polishing process, shortening manufacturing time, reducing manufacturing cost, and improving productivity. The present invention provides a polishing apparatus for a recycled wafer and a polishing method thereof, which can improve the efficiency of the wafer.

Further, another object of the present invention is to provide a polishing apparatus for reclaimed wafers and a polishing method for recycling the abrasive.

According to the present invention, there is provided a polishing apparatus for a recycled wafer, comprising: a surface plate having a polishing portion which rotates about a predetermined rotational axis and the surface of the wafer is in contact polishing; The wafer holder supporting the wafer is detachable and has a holder detachable part, which is seated on the polishing part and rotates according to the rotation of the surface plate, and is supplied with silica (SiO ₂ ), an aqueous solution and diamond powder supplied between the polishing part and the wafer. A plurality of blocks for polishing the wafer with the slurry in the slurry state; It is achieved by a polishing apparatus for a reclaimed wafer, characterized in that it comprises a block head which is arranged to be elevated on the upper surface of the surface plate to which the block is detachably coupled.

Here, the diamond powder has a size of 0.001 ~ 0.3 micrometers, it is possible to reduce the occurrence of scratches on the surface of the wafer during polishing operation and to uniformly polish the defective gallium nitride layer.

The block is provided between the holder detachable portion is formed with at least one injection nozzle hole for injecting the abrasive toward the polishing portion, the block head is in communication with the injection nozzle hole and the flow hole in which the abrasive flows, and in communication with the flow hole The abrasive supply path for receiving the abrasive and supplying the abrasive to the flow hole is formed, so that the abrasive supply point can be easily and uniformly polished, and the loss of the abrasive can be minimized to reduce the cost and improve the productivity. .

The injection nozzle hole is formed at a position adjacent to the wafer, so that the abrasive is directly supplied to the surface plate adjacent to the wafer, so that the abrasive supply point can be easily controlled to grind more uniformly, and also minimize the loss of the abrasive. It becomes possible.

A reservoir for storing the abrasive, an abrasive supply pipe for guiding the abrasive of the reservoir to the abrasive supply path of the block head, and a pump provided on the abrasive supply pipe to pump the abrasive of the reservoir to the upper surface of the block head. It may further include.

By further including an agitator for agitating the abrasive stored in the reservoir, it is possible to smoothly mix the silica and the aqueous solution and the diamond powder to homogenize the concentration of the abrasive.

The wafer is supported by the wafer holder by surface tension, so that the wafer can be easily attached to and detached from the wafer holder.

The polishing part of the surface plate is attached with an adsorption pad in which the polyurethane resin is foamed or impregnated, so that foreign matters do not mix with the abrasive from the surface plate during the polishing operation, and the abrasive can be recycled.

On the other hand, the above object, according to another field of the present invention, in the reclaimed wafer polishing method, comprising: providing a surface plate having a polishing portion that rotates about a predetermined rotation axis, the surface of the wafer is in contact polishing; Mounting the wafer on a plurality of blocks that rotate as the table rotates; Resting the block on the polishing portion of the surface plate; Supplying a slurry in a slurry state containing silica (SiO ₂ ), an aqueous solution, and diamond powder between the block and the polishing unit; And grinding the wafer by rotating the surface plate.

Here, the diamond powder has a size of 0.001 ~ 0.3 micrometers, it is possible to reduce the occurrence of scratches on the surface of the wafer during polishing operation and to uniformly polish the defective gallium nitride layer.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a sectional view of principal parts of a polishing apparatus for a recycled wafer according to the present invention, and FIG. 2 is a plan view of the block head of FIG. As shown in these figures, the polishing apparatus 5 for recycled wafers according to the present invention has a disk-shaped surface plate 10.

The surface plate 10 rotates about a rotating shaft (not shown) connected by a motor (not shown).

The upper surface of the surface plate 10 is provided with a polishing portion 13 on which the surface of the sapphire wafer 3 is in contact polishing. In the polishing unit 13, a suction pad manufactured by foaming or impregnating a polyurethane resin is attached, and foreign matter is not mixed into the abrasive from the surface plate 10 during the polishing operation so that the abrasive can be recycled.

The polishing unit 13 is rotated by the rotation of the surface plate 10, and a plurality of blocks 20 for polishing the sapphire wafer 3 together with the surface plate 10 are seated.

The block 20 has a disk shape and is disposed at equal intervals along the circumferential direction of the surface plate 10. Here, although four blocks 20 are disclosed in this embodiment, the quantity of blocks 20 can be adjusted according to the size of the device 5.

On the plate surface of the block 20 facing the polishing part 13, a plurality of holder attaching and detaching parts 21 are provided, in which the wafer holder 23 supporting the sapphire wafer 3 is attached and detached. The holder detachable portion 21 is recessed to a predetermined depth from the plate surface of the block 20, and the holder detachable portion 21 is disposed at equal intervals in the circumferential direction with respect to the axis of the block 20. Here, although not shown, it is preferable that an insertion groove is formed in the holder detachable portion 21 to allow the wafer holder 23 to be inserted and fixed. In addition, although eight holder detachable parts 21 are disclosed in this embodiment, the quantity of the holder detachable parts 21 may be adjusted according to the size of the device 5.

The wafer holder 23 supports the sapphire wafer 3 so that the plate surface to be polished of the sapphire wafer 3 attached thereto protrudes from the bottom surface of the block 20. As a result, the interference between the wafer holder 23 and the surface plate 10 does not occur during the polishing operation of the sapphire wafer 3.

On the other hand, the wafer holder 23 and the sapphire wafer 3 are supported by the surface tension, so that the sapphire wafer 3 can be easily attached to and detached from the wafer holder 23.

A plurality of injection nozzle holes 25 for injecting abrasives toward the polishing portion 13 of the surface plate 10 are formed between the plurality of holder attaching and detaching portions 21. Each injection nozzle hole 25 is formed in each block 20 in the direction in which the central axis intersects with the surface plate 10, in this embodiment in a substantially vertical direction. Each injection nozzle hole 25 is disposed at a position adjacent to the wafer 3 at regular intervals. As a result, the abrasive is directly supplied to the adjacent surface plate 10 of the sapphire wafer 3, so that the abrasive feed point can be easily controlled and uniformly polished, and the loss of the abrasive can be minimized.

The block 20 is detachably coupled to the block head 30 by fastening means (not shown). Here, a bolt, a pin, etc. may be applied as the fastening means.

The block head 30 disposed on the upper surface of the surface plate 10 is lifted by an elevating means (not shown) and seats the sapphire wafer 3 mounted on the block 20 on the polishing portion 13 of the surface plate 10. The block head 30 is formed with a plurality of flow holes 31 through which the abrasive flows, and each flow hole 31 communicates with the injection nozzle holes 25 of the block 20. Here, the flow hole 31 is formed in each block head 30 in the vertical direction in the present embodiment in the direction in which the central axis intersects with respect to the surface plate 10.

An upper surface of the block head 30 communicates with each of the flow holes 31, and an abrasive supply path 33 for receiving the abrasive and supplying the abrasive to each of the flow holes 31 is formed. The abrasive feed passage 33 has a semicircular arc cross-sectional shape with a semicircle in cross section. The abrasive supply passage 33 has a groove shape recessed to a predetermined depth in the upper surface of the block head 30 in the direction crossing the flow hole 31. The abrasive feed passage 33 in this embodiment is formed between the ring-shaped abrasive feed passage 35 and the sapphire wafer 3 radially at a predetermined interval from one side of the ring-shaped abrasive feed passage 35. It consists of a radial abrasive supply path 37, and each abrasive supply path 35 and 37 communicates with each other.

Meanwhile, the reclaimed wafer polishing apparatus 5 according to the present invention is a silica (SiO ₂ ) material as a main component and supplies a slurry in the form of slurry containing an aqueous solution and diamond powder to the polishing portion 13 of the surface plate 10. It has an abrasive supply unit 40.

The abrasive supply unit 40 includes a reservoir 41 for storing slurry in the form of slurry containing silica (SiO ₂ ), an aqueous solution, and diamond powder, and the abrasive in the reservoir 41 on the upper surface of the block head 30. An abrasive supply pipe 43 for guiding flow and a pump 45 provided on the abrasive supply pipe 43 to pump the abrasive in the reservoir 41 are provided.

In addition, the abrasive supply unit 40 has a stirrer 51 for stirring the abrasive stored in the reservoir 41.

The stirrer 51 has a plurality of blades 53 and a stirring motor 55 for rotating the blades 53, and serves to homogenize the concentration of the abrasive by mixing silica with an aqueous solution and diamond powder.

Herein, the particle size of the diamond powder mixed in the abrasive is preferably 0.001 to 0.3 micrometers, thereby reducing the occurrence of scratches on the surface of the sapphire wafer 3 during the polishing operation and uniformly polishing the defective gallium nitride layer. . In addition, the silica (SiO ₂ ) constituting the abrasive, the aqueous solution and the diamond powder are mixed in an appropriate ratio.

With this configuration, the process of polishing the recycled wafer using the polished wafer 5 for recycled wafers according to the present invention will be described.

First, a plate 10 for rotating and polishing the wafer 3 is prepared.

Next, after the sapphire wafer 3 to be regenerated and polished is attached to the wafer holder 23, the wafer holder 23 is coupled to the holder detachable portion 21 of the block 20.

In addition, the block 20 to which the sapphire wafer 3 is mounted is coupled to the block head 30 by a coupling means (not shown). At this time, the block 20 and the block head 30 are assembled so that each flow hole 31 of the block head 30 and each injection nozzle hole 25 of the block 20 communicate with each other.

Next, the block 20 and the block head 30 on which the sapphire wafer 3 is mounted are seated on the polishing portion 13 of the surface plate 10. At this time, the sapphire wafer 3 is pressed by the own weight of the block 20 and the block head 30 to be in close contact with the polishing portion 13 of the surface plate 10.

Subsequently, an abrasive in a slurry state containing silica, an aqueous solution, and diamond powder stored in the storage tank 41 is used for the abrasive of each block head 30 seated on the polishing unit 13 of the surface plate 10 using the pump 45. Supply to supply path 33 is carried out.

The abrasives supplied to the respective abrasive supply paths 35 and 37 flow toward the respective injection nozzle holes 25 of the block 20 through the respective flow holes 31 of the block head 30.

The abrasive flowed into each injection nozzle hole 25 is spray-fed and supplied to the polishing part 13 of the surface plate 10 adjacent to the sapphire wafer 3. Thus, the abrasive feed point can be easily controlled, and the loss of the abrasive can be minimized.

When the surface plate 10 is rotated by a motor, as shown in FIG. 3, the sapphire wafer 3, the block 20, and the block head 30 may be polished by the inertia force of the polishing portion of the surface plate 10 ( 13) It overcomes friction with 13 and rotates.

As a result, each of the sapphire wafers 3 attached to the block 20 rotates relative to the polishing portion 13 of the surface plate 10, and the surfaces of the respective sapphire wafers 3 are each sapphire wafer 3 and the polishing portion. It is ground by the abrasive interposed between (13).

At this time, the gallium nitride layer formed on the surface of the sapphire wafer 3 is removed by the nanoparticle-sized diamond contained in the abrasive, and at the same time, the surface of the sapphire wafer 3 is ground by the silica component contained in the abrasive. The sapphire surface characteristic of the tax grade is given, and the sapphire wafer 3 is regenerated.

On the other hand, since the suction pad is attached to the polishing unit 13 of the surface plate 10, the abrasive grinding the sapphire wafer 3 can be recycled unlike the conventional because no foreign matter such as tin is mixed.

As such, by spraying and supplying a slurry in the form of a slurry containing silica (SiO ₂ ), an aqueous solution, and diamond powder between the wafer and the polishing plate, the DMP process and the CMP process are simultaneously performed in a single device to regenerate the wafer. It can reduce processes, shorten manufacturing time, reduce manufacturing costs and increase productivity.

Meanwhile, in the above-described embodiment, the block and the block head are described as being coupled to each other by fastening means (not shown), but the block and the block head may be integrally formed.

In addition, in the above-described embodiments, the polishing of the wafer on which the sapphire film is formed is mainly described, but it can be applied to the polishing of high hardness wafers, such as a diamond film (CVD diamond film) synthesized by vapor phase chemical vapor deposition.

As described above, according to the present invention, a diamond mechanical polishing (DMP) process and a chemico-mechanical polishing (CMP) process are simultaneously performed in a single device, thereby reducing wafer regeneration polishing process, shortening manufacturing time, and reducing manufacturing cost. Provided are a polishing apparatus for a recycled wafer and a polishing method thereof which can reduce productivity and improve productivity.

There is also provided a polishing apparatus for a recycled wafer and a polishing method thereof, which can recycle abrasives.

Claims (10)

A surface plate that rotates about a rotation axis and includes a polishing portion on which the surface of the wafer is in contact polishing; A plurality of blocks having a holder detachable part to which the wafer holder for supporting the wafer is detachable, the plurality of blocks seated on the polishing part and rotating according to the rotation of the surface plate; And A block head arranged to be elevated on an upper surface of the surface plate to which the block is detachably coupled; The wafer is polished by the interaction between the polishing unit and the block by using a slurry in a slurry state containing silica (SiO ₂ ), an aqueous solution, and diamond powder supplied between the polishing unit and the wafer. Polishing device for recycled wafers. The method of claim 1, And said particle powder has a particle size of 0.001 to 0.3 micrometers. The method of claim 1, The block is provided between the holder detachable portion is formed with at least one injection nozzle hole for injecting abrasive toward the polishing portion, The block head is a polishing device for a regenerated wafer, characterized in that the flow hole in which the abrasive flows in communication with the injection nozzle hole, and the abrasive supply path for communicating with the flow hole and receiving the abrasive to supply the abrasive to the flow hole is formed. . The method of claim 3, And the injection nozzle hole is formed at a position adjacent to the wafer. The method of claim 3, A storage tank for storing the abrasive; An abrasive supply pipe for guiding flow of the abrasive in the reservoir to an abrasive supply path of the block head; And a pump provided on the abrasive supply pipe to pump the abrasive of the reservoir to the upper surface of the block head. The method of claim 5, And a stirrer for stirring the abrasive stored in the reservoir. The method of claim 1, And the wafer is supported by the wafer holder by surface tension. The method according to any one of claims 1 to 7, And a suction pad on which the polyurethane resin is foamed or impregnated is attached to the polishing part of the surface plate. Providing a surface plate that rotates about a rotation axis and includes a polishing portion at which the surface of the wafer is in contact polishing; Mounting the wafer on a plurality of blocks that rotate as the table rotates; Resting the block on the polishing portion of the surface plate; Supplying a slurry in a slurry state containing silica (SiO ₂ ), an aqueous solution, and diamond powder between the block and the polishing unit; And And rotating the surface plate to polish the wafer. The method of claim 9, And the particle size of the diamond powder is 0.001 to 0.3 micrometers.

Images