KR20070046569A - Apparatus for polishing wafer - Google Patents

Abstract

A wafer polishing apparatus is disclosed. Disclosed is a wafer polishing apparatus for chemical mechanical polishing a wafer, comprising: a polishing table rotatably provided; A polishing pad provided on the polishing table; A polishing block which presses and supports the wafer placed on the polishing pad; And a profile controller disposed at an edge bottom of the polishing block to pressurize the surface of the polishing pad to induce compressive deformation of the polishing pad, and to control the polishing pad thickness profile.

According to the present invention, in the wafer polishing, a profile of the thickness of the polishing pad is formed by prior pressing of the polishing pad by a profile control device mounted on the polishing block, and the polishing pad exhibited by the trajectory motion of the wafer during polishing. By suppressing the deformation, there is an advantage that the polishing uniformity of the wafer affected by the polishing pad deformation can be improved.

Wafer, Chemical Mechanical Polishing, Polishing Pads

Description

Wafer Polishing Machine {APPARATUS FOR POLISHING WAFER}

1 is a configuration diagram schematically showing the configuration of a wafer polishing apparatus according to the prior art.

FIG. 2 is a detailed view showing the main portion of FIG. 1 in more detail. FIG.

Figure 3 is a schematic view showing the configuration of a wafer polishing apparatus according to the present invention.

Figure 4 is a bottom view showing the structure of the seasoning block ring of Figure 3 in more detail.

Figure 5 is a graph showing the thickness profile of the polishing pad applied to the present invention.

<Description of the symbols for the main parts of the drawings>

16. Housing

17. Elastic rubber tube

18. Seasoning Block Ring

20. Polishing block tooth

22. Pneumatic supply line

31. Polishing table

32. Polishing pad

34. Wafer

35. Polishing Block

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus, and more particularly, to control the profile of the thickness of the polishing pad of the wafer polishing apparatus to reduce the deformation of the polishing pad caused by the polishing pad pressing during polishing, and to polish the wafer. The present invention relates to an improved wafer polishing apparatus for improving uniformity.

As semiconductor devices are miniaturized, densified, and multilayered, finer pattern formation techniques are used, and the surface structure of the semiconductor devices is complicated, and the level of interlayer insulating films is also increased.

Therefore, a chemical mechanical polishing (CMP) process is used as a planarization for removing a step in a specific film formed on a wafer (semiconductor substrate).

The CMP process is a process of planarizing the surface of the object to be polished through chemical reaction with a slurry and mechanical processing with a polishing pad.

This CMP process can achieve global planarization compared to the reflow or resist etch-back process that has been used for surface planarization, and can be performed at low temperature. Have

An example of a wafer polishing apparatus used in the above CMP process is schematically illustrated in FIG. 1.

As shown in the drawing, the wafer polishing apparatus rotates by attaching and polishing a polishing pad 12 on a rotating polishing plate 11, and polishing chemicals and reactive chemicals from a nozzle 13 installed on the polishing pad 12. The slurry 13a containing the particles is supplied.

When the wafer 14 is placed on the polishing pad 12, and the wafer 14 is pressed with the polishing block 15, the wafer 14 is rotated in the same direction as the polishing plate 11. To be polished.

FIG. 2 shows the main details of FIG. 1.

As shown, in the polishing apparatus used for polishing the wafer 14, the polishing block 15 serves to mount the simple wafer 14 and to transfer pressure to the entire surface of the wafer 14 so that the wafer ( 14) Enable machining across the entire surface.

In addition, the polishing pad 12 used for polishing the wafer 14 is coated with a nonwoven fabric with a polymeric material, and the polishing pad 14 is particularly compressed by pressing the wafer 14 during polishing, Repeated recovery and permanent deformation results in viscoelastic deformation.

In addition, the pad thickness profile appearing over the entire surface of the polishing pad 12 during polishing affects the polishing uniformity of the wafer 14.

Accordingly, in the conventional wafer polishing apparatus, the total thickness variation after processing caused by the uneven material removal at the edge and the center of the wafer 14 due to the uneven pressure distribution on the wafer 14 due to the deformation of the polishing pad 12 is overcome. In order to achieve this, a specific wafer shape is processed in the polishing process.

The present invention has been made to solve the above problems, the wafer polishing apparatus for controlling the profile of the thickness of the polishing pad to reduce the deformation of the polishing pad by the polishing pad pressure during polishing, and improve the polishing uniformity of the wafer The purpose is to provide.

A wafer polishing apparatus of the present invention for achieving the above object, the wafer polishing apparatus for chemical mechanical polishing the wafer, comprising: a polishing table rotatably provided; A polishing pad provided on the polishing table; A polishing block which presses and supports the wafer placed on the polishing pad; And a profile controller disposed at an edge bottom of the polishing block to pressurize the surface of the polishing pad to induce compressive deformation of the polishing pad, and to control the polishing pad thickness profile.

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

Figure 3 is a schematic diagram showing the configuration of a wafer polishing apparatus according to the present invention.

Referring to the drawings, a wafer polishing apparatus according to the present invention is for performing a chemical mechanical polishing of a wafer, and includes a polishing table 31 rotatably provided, a polishing pad 32 provided on the polishing table 31, The polishing block 35 which presses and supports the wafer 34 on the polishing pad 32, and is disposed at the bottom of the edge of the polishing block 35 to press the surface of the polishing pad 32 so as to press the surface of the polishing pad 32. And a profile control device for inducing compression deformation and controlling the polishing pad 32 thickness profile.

The profile control device includes a housing 16 installed in the space 35a formed by cutting a lower portion of the edge of the polishing block 35 to a predetermined size, and installed in the housing 16 and polished. A seasoning block ring 18 for pressing the surface of the pad 32 and an elastic rubber tube installed in the housing 16 above the seasoning block ring 18 to press the seasoning block ring 18. (tube) 17 and a pneumatic supply device installed in the polishing block 35 to provide pneumatic pressure to the elastic rubber tube (17).

The pneumatic supply device is a pneumatic supply source installed at one side of the polishing block tooth 20 and the polishing block tooth 20 and the polishing block tooth 20 and the polishing block 35, respectively, installed on one side of the wafer polishing apparatus. It is configured to include a pneumatic supply pipe 22 for supplying pneumatic pressure from the (not shown) to supply the pneumatic pressure to the elastic rubber tube (17).

In addition, the abrasive block tooth 20 and the abrasive block 35 are coupled by a predetermined fastening member, for example, a bolt 21. The housing 16 is inserted into and installed in the space 35a of the polishing block 35 and fixed to the polishing block 35.

In addition, the seasoning block ring 18 is installed to press the polishing pad 32 higher than the pressure applied to the wafer 34, and the inner diameter of the seasoning block ring 18 is shown in FIG. 34) larger than the diameter.

The season block ring 18 is made of a ceramic material. This ceramic material includes, for example, alumina (Al 2 O 3) or silicon carbide (SiC).

The bottom of the seasoning block ring 18 is also provided with a spiral flow pocket 23, as shown in FIG. 4.

On the other hand, the elastic rubber tube 17 as shown in Figure 3 is for pressing the seasoning block ring 18 may have a variety of forms. Therefore, the elastic rubber tube 17 is not limited to the form shown in FIG.

Likewise, the seasoning block ring 18 may be formed in various forms for the introduction of the slurry. Thus, as described below, the seasoning block ring 18 is pressed by the elastic rubber tube 17 to minimize deformation of the polishing pad 32 through compression of the polishing pad 32 continuously during polishing.

The narrower the width of the seasoning block ring 18 that is pressed and contacted on the polishing pad 32, the better, and the inner diameter thereof should be larger than the diameter of the wafer 34.

On the other hand, reference numeral 19, which is not described in FIG. 3, shows a pneumatic chamber formed in the elastic rubber tube 17 by supplying pneumatic pressure.

Referring to the operation of the wafer polishing apparatus according to the present invention having the configuration as described above are as follows.

Referring back to the drawings, the wafer polishing apparatus according to the present invention comprises a housing 16 capable of accommodating the seasoning block ring 18 at the outer circumferential edge of the polishing block 35 of ceramic material for mounting the wafer 34. And an elastic rubber tube (17) capable of expanding the pneumatic pressure to press the seasoning block ring (18) inside the housing (16).

Accordingly, the seasoning block ring 18 pressed during polishing presses the surface of the polishing pad 32 to the pressure applied to the wafer 34 or more to compress the deformation of the polishing pad 32 attached to the polishing plate 31. To control the profile.

The seasoning block ring 18 is made of ceramic material such as alumina (Al₂O₃) or silicon carbide (SiC), and overcomes abrasion due to friction with the polishing pad 32 to prevent metal wear during polishing of the wafer 34. It is possible to suppress contamination and scratches.

In addition, as shown in FIG. 4, the bottom of the seasoning block ring 18 is provided with a spiral flow pocket 23 to uniformly flow the slurry supplied to the wafer 34 and discharge the polishing residue.

When the polishing pad 32 is seasoned using the polishing block 35, the deformation of the polishing pad 32 on the polishing plate 31 by the seasoning ring 18 is as shown in FIG. 5. It can be expected to appear.

In the state where the thickness profile of the polishing pad 32 is controlled, when the wafer 34 exists in the area 'A' and moves relative to the polishing pad 32, the polishing uniformity is improved compared to the conventional polishing without in-process seasoning. Will be secured.

As described above, the wafer polishing apparatus according to the present invention has the following effects.

In wafer polishing, the polishing pad is formed by prior pressurization of the polishing pad by a profile control device mounted on the polishing block, and polishing is performed by suppressing the deformation of the polishing pad caused by the trajectory motion of the wafer during polishing. Polishing uniformity of the wafer affected by the pad deformation can be improved.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible. Therefore, the true scope of protection of the present invention should be defined only by the appended claims.

Claims (5)

In the wafer polishing apparatus for chemical mechanical polishing the wafer, A polishing table rotatably installed; A polishing pad provided on the polishing table; A polishing block which presses and supports the wafer placed on the polishing pad; And a profile control device disposed at an edge bottom of the polishing block to pressurize the surface of the polishing pad to induce compressive deformation of the polishing pad, and to control the polishing pad thickness profile. The method of claim 1, The profile control device, A housing installed in a space formed by being cut to a predetermined size under the edge of the polishing block; A seasoning block ring installed in the housing to press the polishing pad surface; An elastic rubber tube installed in the housing above the season block ring to press the season block ring; And a pneumatic supply device installed on the polishing block to provide pneumatic pressure to the elastic rubber tube. The method of claim 2, The pneumatic supply device, A polishing block tooth installed at an upper portion of the polishing block; And a pneumatic supply pipe installed at each of the polishing block teeth and the polishing block to receive pneumatic pressure, and to supply pneumatic pressure to the elastic rubber tube. The method of claim 3, The polishing block tooth and the polishing block are wafer polishing apparatus, characterized in that coupled by a predetermined fastening member. The method of claim 2, And the housing is inserted into the space part and fixed to the polishing block.

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