KR20110062352A

KR20110062352A - Polishing plate improved in cooling member and wafer polishing apparatus having the same

Info

Publication number: KR20110062352A
Application number: KR1020090119051A
Authority: KR
Inventors: 오세열
Original assignee: 주식회사 엘지실트론
Priority date: 2009-12-03
Filing date: 2009-12-03
Publication date: 2011-06-10

Abstract

PURPOSE: A polishing plate with a modified cooling unit wafer polishing apparatus including the same are provided to control the chemical reaction speed of a polishing process by considering mechanical polishing characteristics for each region of a wafer. CONSTITUTION: A polishing plate(100) includes multiple temperature regions(A, B, C) which are formed to the radial direction. Temperature regions forming the multiple temperature regions are respectively controlled by chillers. Temperature regions receive coolant from a first chiller, a second chiller, and a third chiller. The temperature regions respectively maintain cooling temperatures(T1, T2, T3). The cooling temperature with respect to the wafer in contact with the polishing plate is radially defined.

Description

Polishing plate improved in cooling member and wafer polishing apparatus having the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a surface of a wafer, and more particularly, to a polishing plate having a cooling member for cooling heat generated during a polishing process and a wafer polishing apparatus having the same. .

In the wafer manufacturing process, the polishing process is largely divided into stock polishing, which removes the surface deterioration layer of the wafer and improves thickness uniformity, and final polishing, which processes the surface roughness into mirror surfaces around 1 mm. In the polishing process, after the etching or grinding process, the first polishing is performed using a stock pad and a stock slurry, followed by a second polishing using a final pad and a final slurry. Finally, a process of washing the surface of the wafer with ultrapure water is performed.

Currently, in most wafer polishing processes, double side polishing is applied in the stock polishing step, and double side polishing is performed by a wafer polishing apparatus as shown in FIG.

Referring to FIG. 1, a wafer polishing apparatus is a polishing apparatus for polishing a surface of a wafer 1 by performing a relative rotational movement with the carrier 10 while being in contact with the carrier 10 supporting the wafer 1 and the wafer 1. A cooling system having a polishing table 20 equipped with pads 21, a cooling line 30 and a chiller 31 for cooling the polishing table 20, and a wafer 1 And a slurry supply means 40 for supplying a polishing slurry between the polishing pad 21 and the polishing pad 21.

In the wafer polishing apparatus, in particular, the polishing plate 20 is a very important part because the flatness of the wafer 1 is determined according to its shape. Typically, the polishing table 20 is made of a low thermal expansion alloy to prevent deformation due to heat generated during the polishing process, and has a structure in which a cooling line 30 for forcibly cooling the polishing heat is embedded. The cooling line 30 receives cooling water from the chiller 31 to maintain a predetermined cooling temperature.

The structure of the cooling line 30 is somewhat different for each manufacturer, but is commonly formed in the form of a single cooling jacket as shown in FIG. 2, a and b represent inlet and outlet of the cooling water, respectively.

However, the conventional polishing table 20 shares one cooling line 30 in all regions so that the surface temperature is the same from the center portion to the edge portion of the polishing plate, and thus the wafer 1 is chemically used. ), The reaction temperature is constant, but mechanically, the removal rate of the wafer 1 is different, resulting in structural deformation of the wafer 1. That is, as the grinding process proceeds, the edge portion of the wafer 1 has a higher relative speed than the center portion, so that the removal rate of the edge portion is high, which causes the wafer to be convex in the center when polishing is completed. Processed into forms.

In order to solve the problem of poor flatness of the wafer, a method of adjusting the chemical reaction temperature by dividing the cooling temperature of the wafer into regions can be considered, but the conventional polishing table having the cooling line can be implemented. There is an impossible limitation.

The present invention has been made to solve the above problems, and an object thereof is to provide a polishing table capable of forming a multi-temperature region in a radial direction and a wafer polishing apparatus having the same.

In order to achieve the above object, the present invention discloses a polishing table having a structure in which a plurality of individually controllable cooling members are arranged in a radial direction.

That is, the polishing table for wafer polishing apparatus according to the present invention includes a disk-shaped plate body having a flat surface to which the polishing pad is attached; And a plurality of cooling members installed on the surface plate body and arranged independently of each other while radially moving in the surface plate body to provide different temperature regions.

The cooling member has a jacket structure for providing a flow path of the cooling water, and is preferably embedded in the surface plate body.

Preferably, at the boundary of the temperature zones, the cooling members of different temperature zones may be arranged to overlap.

According to another aspect of the invention, the carrier for supporting the wafer to be polished; A disk-shaped polishing table having a flat surface on which the polishing pad is attached, the disk-shaped polishing table being installed to be in relative rotational motion with the carrier while being in contact with the wafer; And a cooling system including a plurality of cooling members arranged in a radial direction of the polishing table to enable differentiation of the regions to provide different temperature regions, and a chiller for individually controlling the temperature of the cooling members. A polishing apparatus is provided.

According to the present invention, the shape of the wafer after polishing may be variously controlled by controlling the radial temperature profile of the wafer by using the multi-temperature region formed on the polishing table. Therefore, it is possible to improve the polishing flatness of the wafer by controlling the chemical reaction rate in consideration of the mechanical polishing characteristics of each region of the wafer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

A wafer polishing apparatus according to a preferred embodiment of the present invention includes a carrier for supporting a wafer to be polished, a polishing table installed to enable relative rotational movement with the carrier to polish the wafer, and a cooling system for forming a multi-temperature region on the polishing table. And slurry supply means for supplying a polishing slurry between the wafer and the polishing pad. Here, since the basic coupling relationship between the wafer, the carrier, the polishing plate, and the slurry supply means is the same as that of the conventional polishing apparatus described with reference to FIG. 1, a detailed description thereof will be omitted.

3 schematically shows the structure of the polishing table and the cooling system provided in the wafer polishing apparatus according to the preferred embodiment of the present invention.

Referring to Figure 3, the polishing table 100 provided according to a preferred embodiment of the present invention includes a multi-temperature zone (A, B, C) is divided in the radial direction.

Each temperature region constituting the multi-temperature regions A, B, and C is individually controlled by a chiller corresponding thereto. 3 shows an example in which temperature regions A, B, and C receive cooling water from chiller # 1, chiller # 2, chiller # 3, respectively, and maintain cooling temperatures of T1, T2, and T3. Although the drawing table 100 divided into three temperature ranges is shown in the drawings, the present invention is not limited to this example, and various modifications may be made to the number of temperature ranges formed in the polishing table 100. to be.

When the temperature of the multi temperature zones A, B, and C formed on the polishing table 100 are individually controlled, the cooling temperature of the wafer in contact with the polishing table 100 is radially divided and chemical reaction temperature is determined. It is possible to adjust.

4 schematically shows a wafer shape in the case where T1, T2, and T3 of the polishing table 100 are individually controlled by using the cooling system provided according to the present invention.

Referring to FIG. 4, when the temperature of T2 is controlled higher than T3 and T1 as in Case 1, the polishing speed of the center portion of the wafer is increased, and thus the shape of the wafer after the polishing process is concave. As shown in Fig. 2, when the temperature of T2 is controlled lower than that of T3 and T1, the polishing rate on the outside of the wafer is increased, resulting in a convex shape. As such, by controlling T1, T2, and T3 by temperature region, the shape of the wafer can be freely implemented as desired.

The polishing table 100 has a disk shape having a flat surface to which a polishing pad is attached, and has a plurality of cooling members 101, 102, and 103 corresponding to the multi-temperature regions A, B, and C as shown in FIG. 5. ) Is arranged.

The plurality of cooling members 101, 102, 103 are arranged one by one in the radial direction of the polishing table 100 to provide mutually independent cooling functions. Preferably, the cooling members 101, 102, and 103 are configured in the form of a cooling line having a jacket structure in which a flow path for circulating cooling water is formed. The cooling lines are individually supplied with cooling water from the corresponding chillers to maintain different temperatures, thereby providing different temperature ranges. In addition, the cooling members 101, 102 and 103 may be constituted by various types of cooling members as long as they can provide a cooling function.

In order to increase the contact area between the cooling members 101, 102, 103 and the polishing plate 100, the cooling members 101, 102, 103 are arranged to extend in a zigzag form along the circumferential direction for each temperature region. At this time, the cooling members (101, 102, 103) is preferably arranged so that the overlap (Overlap) between different temperature zones at the boundary of the temperature zones. According to this arrangement, it is possible to prevent a large temperature gradient from occurring at the boundary of the temperature regions, thereby minimizing the physical impact of the polishing table 100 and the rapid chemical reaction rate change of the wafer.

In the wafer polishing apparatus having the above-described configuration, the surface of the wafer is smoothly processed by controlling the wafer removal rate according to the chemical reaction rate by individually controlling the cooling temperature of the polishing table for each temperature region during the polishing process. At this time, if the radial temperature profile of the polishing table is controlled in consideration of wafer specifications, rotational speed, polishing table speed, and polishing rate, the weakness of the radial mechanical polishing characteristics of the wafer, which has been a problem in the conventional wafer polishing process, can be eliminated. It is possible to solve and to smoothly polish the surface of the wafer.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical spirit of the present invention, the present invention includes matters described in such drawings. It should not be construed as limited to.

1 is a block diagram of a typical wafer double-side polishing apparatus,

Figure 2 is a plan view showing a cooling line arrangement of the polishing table according to the prior art,

Figure 3 is a schematic diagram showing a multi-temperature region of the polishing plate provided in the wafer polishing apparatus according to a preferred embodiment of the present invention,

4 is a table illustrating the shape of a wafer according to temperature control for each temperature region in FIG. 3;

FIG. 5 is a plan view illustrating an arrangement structure of the cooling member in FIG. 3.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS

100: polishing plate 101,102,103: cooling member

Claims

A polishing table mounted on a wafer polishing apparatus for polishing a surface of a wafer,

A disk-shaped surface plate having a flat surface to which a polishing pad is attached; And

And a plurality of cooling members installed on the surface plate body and arranged independently from each other in a radial direction of the surface plate body to provide different temperature ranges.

The method of claim 1,

The cooling member is made of a jacket structure for providing a flow path of the cooling water, the polishing table for a wafer polishing apparatus, characterized in that embedded in the surface plate body.

The method of claim 1,

A polishing table for a wafer polishing apparatus, characterized in that the cooling members of different temperature regions are arranged to overlap at the boundary of the temperature regions.

A carrier supporting the wafer to be polished;

A disk-shaped polishing table having a flat surface on which the polishing pad is attached, the disk-shaped polishing table being installed to be in relative rotational motion with the carrier while being in contact with the wafer; And

Wafer polishing comprising: a cooling system having a plurality of cooling members arranged in a radial direction of the polishing table to enable differentiation of regions to provide different temperature regions, and a chiller for individually controlling the temperature of the cooling members. Device.

5. The method of claim 4,

The cooling member is made of a jacket structure for providing a flow path of the cooling water, the wafer polishing apparatus, characterized in that embedded in the surface plate body.

5. The method of claim 4,

Wafer polishing apparatus, characterized in that the cooling member of the different temperature region at the boundary of the temperature region is arranged to overlap.