KR101247854B1 - Control system of wafer polishing apparatus - Google Patents

Abstract

Embodiments include a metal plate disposed on a base plate and having a pattern formed thereon; A pattern processing portion disposed on the metal surface plate; And it provides a polishing control system for a wafer comprising a control unit for controlling the movement of the pattern processing unit and a wafer polishing method using the same.

Description

Wafer Polishing Control System {CONTROL SYSTEM OF WAFER POLISHING APPARATUS}

An embodiment relates to a wafer polishing control system and a wafer polishing method using the same.

Recently, gallium nitride-based LEDs have been used in various fields such as high-brightness white LEDs for illumination, LCD backlight units, signals, backlight sources for TFT-LCDs, mobile phone backlight sources and keypads. In the manufacture of such LEDs, an essential material is a sapphire wafer in which a gallium nitride compound such as GaN or GaAlN is formed into a semiconductor epitaxial layer.

Most of the sapphire wafers are manufactured in the following order. First, a sapphire ingot circularly processed into the diameter of the substrate is cut using a diamond wire, or the substrate grown in the shape of a plate is circularly cut into the diameter. Then, the wafer is double-sided lapping the surface in order to remove the thickness variation, the wire marks and wafer distortion generated during cutting, and the edges are processed so as not to be sharp.

Next, the wafer is adhered with wax on the ceramic block for planarization and mirror processing of the sapphire wafer. The wafer attached on the ceramic block is brought into close contact with the metal plate by pneumatic pressure. Thereafter, the surface roughness and stress generated during lapping by a diamond mechanical polishing (DMP) are removed.

The DMP process mainly uses a polishing apparatus used in a chemical mechanical polishing (CMP) process of a conventional silicon wafer. In general, a silicon wafer polishing apparatus is a silicon bonded to a ceramic block between a SUS platen and a pressing head through a slurry composed mainly of a non-woven pad attached to the SUS plate and silica abrasives through rotational movements of the SUS platen and four pressing heads. The surface of the wafer is chemically and mechanically polished.

Polishing equipment of the DMP process is divided into three types, and divided into metal surface plate, pressure head, control system. However, due to the high hardness of the sapphire material, the deformation of the metal surface easily occurs during the processing, which is a factor that causes a sharp deterioration of the quality of the processed wafer such as flatness. In order to remedy this problem, a system for shape control of a metal surface is indispensable. On the other hand, the conventional CMP polishing device for silicon wafers, there is a problem that the pressurized head height and position interferes with the mounting and driving of the control system for precision processing.

The embodiment provides a wafer polishing control system capable of manufacturing a wafer having improved polishing and flatness by easily controlling the shape of the metal surface as well as low processing cost.

A polishing control system for a wafer, according to an embodiment, is disposed on a base plate and includes a patterned metal plate; A pattern processing portion disposed on the metal surface plate; And a control unit for controlling the movement of the pattern processing unit.

A method of polishing a wafer using a polishing apparatus including a base plate, a patterned metal plate, a pressing head, and a control unit including a pattern processing unit, according to an embodiment, the method comprising: between the patterned metal plate and the pressing head. Loading a wafer and polishing the wafer; And unloading the wafer and controlling the pattern of the metal surface with the pattern processing portion.

The wafer polishing control system according to the embodiment controls the shape of the metal surface pattern by a control part including a pattern processing portion, thereby providing a metal surface having a uniform pattern even in a repeated polishing process. Accordingly, the embodiment can provide a wafer with improved polishing and flatness. In addition, the embodiment can minimize the vibration that can occur during the polishing and control process by the control unit having a three-axis structure.

In addition, the polishing control system of the wafer according to the embodiment can use a conventional CMP device for silicon wafers, it is possible to reduce the investment cost and process cost when using the idle equipment for conventional silicon wafers.

1 is a front view of a polishing control system according to an embodiment.
2 is a plan view of a polishing control system according to an embodiment.
3 is a side view of an abrasive control system according to an embodiment.
4 is a perspective view for explaining the driving of the polishing control system according to the embodiment.
5 is a graph illustrating a pattern profile before and after a control step according to an embodiment.

In the description of the embodiment, in the case where each plate, pad, wafer, or layer is described as being formed "on" or "under" of each plate, pad, wafer or layer, "On" and "under" include both being formed "directly" or "indirectly" through other components. In addition, the criteria for the upper or lower parts of each component will be described based on the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 is a front view of a polishing control system of a wafer according to an embodiment. Referring to FIG. 1, a polishing control system for a wafer according to an embodiment includes a lower polishing shelf 10, a plate 20, a cooling member 100, a first base, a second base, a metal surface 300, and a pressing head. 30 and a control unit.

First, the cooling member 100, the first base plate 210, the second base plate 220, and the metal plate 300 are sequentially disposed on the plate 20.

The cooling member 100 is disposed to cool the heat generated during the polishing process. The cooling member 100 may include a cooling line or a chiller for cooling the base plate 200 and the metal plate 300.

The base plate 200 is disposed under the metal plate 300 to maintain the deformation and flatness of the metal plate 300. In more detail, the base plate 200 may be disposed between the cooling member 100 and the metal plate 300. In general, since the metal surface plate 300 is formed to have a much thinner thickness than the base surface plate 200, the metal surface plate 300 may be easily deformed or degraded by the heat and pressure generated in the polishing process. In order to solve the above problems, the base plate 200 may be disposed below the metal plate 300.

In addition, the base plate 200 may be formed of one or a plurality of plate. For example, the base plate 200 may include a first base plate 210 and a second base plate 220 as shown in FIG. 1. The first base plate 210 and the second base plate 220 may be the same material or different materials. For example, both of the first base plate 210 and the second base plate 220 may be SUS plates.

At this time, the first base plate 210 may be a SUS plate used in the conventional CMP device for silicon wafers. That is, the embodiment is a simple to place the second base plate 220 and the metal base plate 300 disposed on the second base plate 220 on the existing SUS plate (first base plate 210) for CMP By the method, the idle equipment for the existing silicon wafer can be used efficiently. Accordingly, the wafer polishing control system according to the embodiment can reduce the investment cost and the process cost.

In addition, when the base plate 200 is formed of a plurality of plate, each plate can be separated. For example, the first base plate 210 and the second base plate 220 may be separated. Therefore, when the metal surface plate 300 is deformed during the polishing process of the high hardness sapphire wafer, only the second base surface plate 220 and the consumed metal surface plate 300 are lifted to lift the metal surface plate 300. It can be replaced.

The surface of the metal surface 300 is patterned. In more detail, the surface of the metal surface 300 directly contacting the wafer of the metal surface 300 is patterned. A general DMP process loads the sapphire wafer between the metal plate 300 and the pressurized head 30, and supplies the slurry containing diamond particles and oil (or superion water) to the metal plate 300 and the pressurized head. The sapphire wafer is polished by crimping and rotating 30 at a constant pressure. At this time, the slurry is continuously supplied to the center portion of the metal surface plate 300 and gradually moved to the edge of the metal surface plate 300 by the rotation of the metal surface plate 300. As such, the surface of the metal surface 300 is patterned so that the slurry supplied in the polishing process may be continuously and uniformly distributed with respect to the surface of the metal surface 300. For example, the surface of the metal surface plate 300 may have a shape in which a predetermined groove is patterned in a spiral shape.

On the other hand, as mentioned above, the sapphire wafer is easily deformed in the polishing process due to its high hardness, and the quality of the sapphire wafer is deteriorated rapidly.

In order to solve the above problems, the embodiment is intended to control the shape of the metal surface plate 300 by the pattern processing unit 400 and the control unit. That is, the wafer polishing control system according to the embodiment may perform a periodic control operation according to the deformation degree of the shape of the metal surface 300 and the deformation degree of the pattern.

The pattern processing unit 400 is disposed on the metal surface plate 300. The pattern processing unit 400 may directly contact a pattern formed on the surface of the metal surface 300 or the surface of the metal surface 300. That is, the pattern processing part 400 is disposed in direct contact with the surface of the metal surface 300 or the surface of the metal surface 300 and at the same time, the surface friction generated by the rotation of the metal surface 300. As a result, the surface of the metal surface 300 or the pattern of the metal surface 300 may be processed.

The pattern processing unit 400 may include a processing tip 410 and a processing head 420 wrapped around the processing tip 410. The processing tip 410 can be used without particular limitation as long as it is a metal working member used in a conventional wafer polishing process. In addition, the shape and size of the processing tip 410 is formed corresponding to the shape and size of the pattern. For example, when a pattern having a width of about 1 μm is formed on the metal surface plate 300, the width of the processing tip 410 may also be about 1 μm.

In addition, the height of the pattern processing unit 400 with respect to the metal surface 300 may be adjusted. For example, the pattern processing unit 400 may be controlled while maintaining a constant depth of about 10 ㎛ to about 1000 ㎛ with respect to the metal surface 300.

In the processing process by the pattern processing unit 400, the rotation speed of the metal surface 300 is not particularly limited. That is, the metal surface plate 300 may be rotated from low speed to high speed as needed. For example, the metal surface plate 300 may be rotated at about 20 rpm to about 50 rpm. When surface processing is required for the flatness of the surface of the metal surface 300, the metal surface 300 is preferably driven at a low speed. In addition, in the case of processing the pattern or the surface of the pattern, the metal surface plate 300 is preferably driven at high speed.

Referring to FIG. 1, the controller is connected to the pattern processing unit 400. The control unit controls the movement of the pattern processing unit 400. The position of the control unit is not particularly limited as long as it can be fixedly arranged in the polishing control system of the wafer. For example, the controller may be fixed to the polishing shelf or the plate 20.

The control unit includes a three-axis drive unit 500 capable of driving the pattern processing unit 400 in the first to third directions. Therefore, the embodiment can minimize vibrations that may occur during the polishing and control process, compared to the conventional one-axis or two-axis drive.

In more detail, the three-axis drive unit 500 is connected to the pattern processing unit 400, the first drive unit 510 for moving the pattern processing unit 400 in the first direction; A second driver 520 connected to the first driver 510 and moving the pattern processing part 400 in the second direction; And a third driving part 530 connected to the second driving part 520 and moving the pattern processing part 400 in the third direction.

The first driving part 510 is connected to the pattern processing part 400. In more detail, the first driving unit 510 may fix or move the pattern processing unit 400. The first driver 510 extends in the first direction. For example, the first direction may mean left and right directions based on a cross section of the metal plate 300. Accordingly, the pattern processing unit 400 may be easily moved in the first direction on the metal surface plate 300.

The second driver 520 is fixed to one end of the first driver 510 and extends in the second direction. For example, the second direction may mean an up and down direction based on a cross section of the metal plate 300. In this case, the second driving unit 520 may be formed extending in one direction of the second direction, more specifically, below the metal plate 300. Accordingly, the pattern processing unit 400 can be easily moved in the second direction.

That is, the pattern processing unit 400 may be in contact with or separated from the wafer while moving in the second direction. For example, the pattern processing unit 400 may move in the second direction and be disposed at a depth of about 10 μm to about 1000 μm on the surface of the metal surface 300, but is not limited thereto.

The third driver 530 is connected to one end of the second driver 520 and extends in the third direction. The third direction may mean a front-rear direction based on the cross section of the metal plate 300. Accordingly, the control unit including the pattern processing unit 400 can be easily moved in the third direction. For example, the pattern processing unit 400 may be moved in a sliding manner in the third direction.

In addition, referring to FIG. 4, the controller may include a fixing part 540 disposed in parallel with the third driving part 530 and fixing the three axis driving part 500. For example, the fixing part 540 may be connected to one end of the first driving part 510 and may be fixed to an upper grinding shelf (not shown in FIG. 1 of FIG. 1) of the system.

During the polishing process, the control unit may be disposed behind the metal surface plate 300 and the pressing head 30. In addition, while the polishing process is finished and the control process is performed, the controller may be disposed in the space between the metal surface plate 300 and the pressure head 30. Accordingly, the wafer polishing control system according to the embodiment can solve the problem of structural interference that may occur when the control unit is mounted on a conventional CMP polishing apparatus for silicon.

The polishing method of the wafer according to the embodiment intends to use the polishing control system of the above-mentioned wafer. For a description of the wafer polishing method, refer to the description of the wafer polishing control system described above. That is, the description of the polishing control system of the wafer described above may be essentially combined with the description of the present manufacturing method.

According to an embodiment, a method of polishing a wafer may include loading a wafer between the metal plate 300 on which the pattern is formed and the pressing head 30 and polishing the wafer; And unloading the wafer and controlling the pattern of the metal surface 300 by the pattern processing unit 400.

That is, after the polishing step is performed, the control step may be performed. The polishing step and the control step may be performed alternately. For example, the polishing step and the control step may be performed alternately or regularly. For example, after a plurality of sapphire wafers are polished a plurality of times by the polishing step, when the flatness of the metal plate 300 or the shape of the pattern is required to be controlled, the control step may be performed.

5 is a graph of comparing the profile of the pattern formed on the surface of the metal surface plate 300 before and after the control step. The profile was observed by selecting a plurality of arbitrary regions (1 to 6 regions) on the metal surface 300. Before the control process, it can be seen that the deformation of the pattern of the metal surface 300 is caused by the polishing process very large. In addition, it can be seen that the degree of deformation is very different depending on the first to sixth region.

On the other hand, it can be seen that after the control process, the degree of deformation is very constant over the first to sixth regions. That is, it can be seen that after the control process, the pattern is constantly corrected to within about 100 μm.

The polishing method of the wafer according to the above-described embodiment may constantly correct the flatness of the metal surface 300 and the shape of the pattern formed on the surface of the metal surface 300 by the pattern processing unit 400. . Accordingly, the surface residence time of the surface of the metal surface 300 of the slurry including the diamond particles may be kept constant by the pattern of the surface of the surface of the metal surface 300. As a result, the polishing control system of the wafer according to the embodiment may provide a wafer having improved polishing and flatness.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

10: lower grinding shelf 400: pattern processing part
20: plate 410: machining tip
30: pressurized head 420: machining head
40: upper grinding lathe 500: 3-axis drive part
100: cooling member 520: first drive unit
200: base plate 530: second drive unit
210: first base plate 530: third drive portion
220: second base plate 540: fixed portion
300: metal plate

Claims (7)

A metal plate disposed on the base plate and having a pattern formed thereon;
An upper polishing shelf disposed above the metal surface plate and equipped with a pressing head for pressing the wafer;
A pattern processing portion disposed on the metal surface plate; And
And a control unit controlling the movement of the pattern processing unit.
The control unit includes a three-axis drive unit for driving the pattern processing unit in a first direction to a third direction with respect to the metal surface plate,
The three-axis drive unit is connected to the pattern processing unit and the first drive unit for moving the pattern processing unit in the first direction, and the second drive unit connected to the first drive unit for moving the pattern processing unit in the second direction And a third driving part connected to the second driving part to move the pattern processing part in the third direction, and a fixing part connected to one end of the first driving part and fixed to the upper polishing shelf.
The control unit, according to the process, the polishing control system of the wafer is disposed behind the metal surface and the pressing head or disposed between the metal surface and the pressing head. delete delete The method of claim 1,
And the base plate includes a first base plate and a second base plate disposed on the first base plate, wherein the first base plate and the second base plate are removable.
The method of claim 1,
And the pattern processing portion controls a deformation of the pattern of the metal plate.
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