KR100252765B1 - Polishing apparatus having depression region facing edge of wafer in polishing part and polishing method using same - Google Patents

Abstract

PURPOSE: A polishing device with a sunken part corresponding to an edge of a wafer and a polishing method using the same are provided to improve the polishing uniformity by reducing an area of a contact part between an edge of a wafer and a polishing member. CONSTITUTION: A polishing device comprises a carrier(5), a polishing pad(21), and a polishing plate(1). The carrier(5) supports, rotates, and transfers a wafer(3). The polishing pad(21) has the first sunken part corresponding to an edge of the wafer(3). The polishing pad(21) is loaded on the polishing plate(1). An insertion member is loaded on the polishing plate(1). The insertion member has a shape of doughnut. The polishing plate(1) rotates the polishing pad(21). The wafer(3) and the polishing plate(1) are rotated in a state that the sunken part is faced to an edge portion of the wafer(3).

Description

Polishing apparatus having depression region facing edge of wafer in polishing part and polishing method using same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus having an improved polishing means and a polishing method using the same, in particular corresponding to a wafer edge at a polishing contact used for chemical mechanical polishing (CMP) of a wafer in a semiconductor manufacturing process. A polishing apparatus having a depression and a polishing method using the same.

In general, chemical and mechanical polishing methods are widely used in the interlayer oxide film planarization, trench isolation, metal plug forming process, and silicon on insulator (SOI) wafer fabrication process of semiconductor devices. A conventional polishing means and a polishing method will be briefly described with reference to the accompanying drawings, as shown in FIG. 1A, a disk-shaped polishing pad 2 for polishing in contact with the wafer 3 and the polishing pad 2. In the polishing apparatus consisting of a polishing plate (1) attached to the upper surface and rotating, and a carrier (5) attached to the wafer (3) and rotated in contact with the polishing pad (2), the upper surface of the polishing plate (1) Polishing is performed by contacting the polishing pad held on the carrier 5 while rotating the wafer 3 held on the carrier 5 while supplying a predetermined amount of polishing liquid 4 onto the rotating polishing pad 2 while being attached. Accordingly, since the polishing pad 2 is gradually worn out due to friction with the wafer 3, the polishing pad is replaced after polishing about 50 to 300 wafers.

In the polishing process using the conventional polishing apparatus described above, the wafer polished with the polishing pad in the state immediately before replacement has a poor polishing uniformity compared with the wafer polished with the newly replaced polishing pad. This is because, as time passes, the polishing progression speed is increased at the edge of the wafer 3 and the polishing progression rate is slow at the center of the wafer. As shown in FIG. 1B, when considering the rotation of the polishing pad 2, the portion of the polishing pad 2 in contact with the center portion of the wafer 3 is relative to the portion of the polishing pad 2 in contact with the edge of the wafer 3. As a result, the contact time with the wafer is long, and the polishing pad wears out quickly, resulting in a decrease in the polishing speed of the center portion of the wafer, resulting in a poor polishing uniformity of the workpiece wafer. There was a problem that is shortened.

Accordingly, the present invention devised to solve the above problems can intentionally reduce the time for which the wafer edge portion is in contact with the polishing means during the polishing process, thereby prolonging the replacement life of the polishing means, and improving the polishing uniformity of the wafer. It is an object to provide a polishing apparatus. It is also an object of the present invention to provide a polishing method capable of effectively achieving the above object by using the polishing apparatus appropriately.

1A and 1B are a perspective view and a plan view showing an exemplary configuration and polishing method of a conventional CMP polishing apparatus;

2a and 2b is an exploded perspective view and a perspective view showing an embodiment of the CMP polishing apparatus polishing means according to the present invention,

FIG. 2C is a cross sectional view taken along line I-I in FIGS. 2A and 2B;

3a and 3b are exploded perspective and perspective views showing another embodiment of the CMP polishing apparatus polishing means according to the present invention,

3C is a cross sectional view taken along the line I-I in FIGS. 3A and 3B;

Figures 4a and 4b is an exploded perspective view and a perspective view showing another embodiment of the CMP polishing apparatus polishing means according to the present invention,

4C is a cross sectional view taken along the line I-I in FIGS. 4A and 4B;

5a and 5b is an exploded perspective view and a perspective view showing another embodiment of the CMP polishing apparatus polishing means according to the present invention,

FIG. 5C is a cross sectional view taken along the line I-I in FIGS. 5A and 5B;

6A to 7B are plan views and cross-sectional views showing a polishing apparatus and a polishing method including the polishing means of FIGS. 2A to 2C.

* Explanation of symbols for the main parts of the drawings

1: polishing plate 2, 21, 22, 31, 32: polishing pad

3: wafer 4: polishing liquid

5: carrier 21a, 22a, 31b, 32b: center depression

22b, 22c: outer recess 31, 32: insertion pad (insertion member)

31a, 32a: opening

The present invention for achieving the above object is a wafer polishing apparatus comprising: a carrier for supporting, rotating and transporting a wafer; A polishing pad positioned at a central portion thereof and having a first depression corresponding to an edge of the wafer; And a polishing plate attached to the upper surface of the polishing pad to rotate the polishing pad.

In the wafer polishing apparatus, the polishing pad may include a second recessed portion corresponding to an edge portion of the wafer at an edge portion thereof.

In addition, the present invention for achieving the above object is a carrier for supporting, rotating and transporting the wafer; Rotating abrasive plates; A donut-shaped insertion member mounted on the polishing plate and having a hole in a central portion thereof corresponding to an edge of the wafer; And a polishing pad formed on the polishing plate on which the insertion member is mounted, the polishing pad having a first recessed portion at the center thereof by the insertion member.

The insertion member is smaller than the outer diameter of the polishing plate and the polishing pad, so that the polishing pad has a second recessed portion corresponding to an edge portion of the wafer at its edge.

In addition, the present invention for achieving the above object is a carrier for supporting, rotating and transporting a wafer, a polishing pad having at least one recess corresponding to the edge of the wafer and polishing to attach and rotate the polishing pad to the upper surface A method of polishing a wafer using a wafer polishing apparatus including a plate, the wafer polishing method comprising rotating the wafer and the polishing plate while the edge portion of the wafer faces the depression.

The wafer may be polished while the wafer is transported in the radial direction of the polishing pad by using the carrier.

Hereinafter, with reference to the accompanying drawings will be described a variety of embodiments of the polishing means of the CMP polishing apparatus of the present invention and the preferred polishing method using the CMP polishing apparatus having the polishing means.

Since the polishing apparatus according to the present invention is constructed in the same manner as the polishing apparatus of FIG. 1A except for various types of polishing means, the same parts and the parts performing the same functions are denoted by the same reference numerals as the polishing apparatus of FIG. Reference numerals are omitted, and description will mainly be made of the differences from the embodiments in the prior art.

As mentioned above, the object of the present invention can be achieved by forming the surface of the polishing means, which is primarily in contact with the wafer surface, in a desired shape. Therefore, in the present invention, polishing means having polishing surfaces of various shapes for achieving the above object is provided. 2a to 5b show various grinding means according to the invention.

2A and 2B show an embodiment configuration of the polishing means according to the present invention, and FIG. 2C shows a cross section of the polishing means according to this embodiment taken along the line I-I in FIGS. 2A and 2B. In the present embodiment, the polishing means, as shown in the drawing, attaches the polishing pad 21 and the polishing pad 21 having the depression 21a having a central portion lower than the upper surface in a predetermined radius size to the upper surface. It consists of a rotating abrasive plate.

Therefore, when the polishing pad 21 according to the present embodiment is attached to the polishing plate 1 to perform polishing of the wafer 3, as shown in FIGS. 6A and 6B, one edge of the wafer 3 is used. The part is located on the recessed portion 21a of the polishing pad, and the other opposite edge portion is located on the outer side of the polishing pad 21 and is in contact with it. Thereby, it is possible to reduce the difference in polishing speeds between the edge of the wafer 3 and the center portion.

Then, applying the polishing method using the polishing means 21 described next, it is possible to obtain the desired effect according to the above object. 6A, 6B, 7A and 7B, a preferred polishing method using the polishing means 21 of this embodiment will be described.

In the embodiment of FIGS. 2A-2C, the contact time between the edge of the wafer 3 and the polishing pad 21 is intentionally reduced by recessing the central portion of the polishing pad 21 in contact with one edge of the wafer. However, since the portion of the polishing pad 21 except for the recessed portion has a difference in line speed depending on the radius, the difference in polishing rate of the center portion and the edge portion of the wafer remains somewhat. Thus, the wafer 3 that rotates while contacting the rotating polishing pad 21 is still present by reciprocating control movement in the radial direction of the polishing pad without being fixed in its position as shown in FIGS. 6A and 6B. It is possible to offset the difference in polishing rate. That is, the polishing process is carried out while reciprocally transferring the rotating wafer 3 in contact with the rotating polishing pad 21 between the line II-II shown in Fig. 6B and the line II'-II 'shown in Fig. 7B. Perform. As a result, the nonuniform wear of the polishing pad due to the difference in the polishing speeds of the center portion and the edge portion of the wafer 3 as described above is eliminated by the polishing method by reciprocating transfer, so that the replacement life of the polishing pad can be further extended. In addition, this makes it possible to obtain a very uniform polishing surface of the wafer 3 than when polishing the wafer using the conventional polishing pad 2.

3A and 3B show another embodiment of the polishing means according to the present invention, and Fig. 3C shows a cross section taken along the line I-I in Figs. 3A and 3B. As shown, the polishing means according to the present embodiment, unlike the embodiment of Figs. 2a to 2c, has a polishing pad having depressions 22a and 22b formed below the original pad surface not only at the center but also at the edge thereof. 22) and the polishing pad 22 attached to the upper surface and rotating plate (1). As described above, the recess 22b is also formed at the edge of the polishing pad 22, so that the wafer edge portion is formed with the polishing pad as compared with the polishing pad 21 (see FIGS. 2A to 2C) of the previous embodiment. The contact time can be further reduced. Since the polishing method using the polishing means 22 according to the present embodiment is the same as in the case of the previous embodiment described above, description thereof is omitted here.

4A and 4B show another embodiment of the polishing means according to the present invention, and FIG. 4C shows a cross section taken along the line I-I of FIGS. 4A and 4B. As shown, the polishing means in this embodiment includes a conventional polishing pad 2 having a flat surface, a polishing plate 1 which rotates by attaching and supporting the polishing pad 2, and the polishing pad 2 and the The polishing pad 2 is interposed between the polishing pads, and the polishing pad 2 is attached to the upper surface thereof, and the lower surface thereof is supported and fixed to the polishing plate 1 to form a surface contour of the polishing pad 2 attached to the upper surface thereof in a desired shape. When the polishing pad 2 is attached to the upper surface of the insert pad 31, the shape of the insert pad 31 is a donut-shaped with the opening 31a formed by removing the center portion with a predetermined radius. Due to the opening 31a, the center portion of the polishing pad 2 is recessed to attach directly to the polishing plate 1, and consequently, at the center portion of the polishing means, as shown in FIG. 31b) is formed. In addition, the outer diameter of the insertion pad is equal to the diameter of the polishing plate 1 and the polishing pad 2, and is attached concentrically with the polishing plate 1 and the polishing pad 2 to constitute the polishing means. Therefore, the polishing means in this embodiment can function in the same manner as the polishing means as in the embodiment in Figs. 2A to 2C. In other words, as shown in FIG. 4C, an insertion pad 31 having a predetermined central portion removed is attached to the polishing plate 1 to which the conventional polishing pad 2 is attached, and an upper surface of the insertion pad 31 is attached. A conventional polishing pad 2 is attached to the center, and the center portion of the outer surface of the polishing pad 2 is recessed into the opening 31a of the insertion pad 31 so that the outer surface of the pad has an outline of the polishing pad 21 of Fig. 1A. By forming the same shape as, to constitute a new polishing means that can perform a more improved polishing. When the polishing process is performed by configuring the polishing means as described above, the same effect as in the polishing means of FIGS. 2A to 2C can be obtained, and in addition, polishing as shown in FIGS. 2A to 2C and 3A to 3C. Since the conventional polishing pad 2 can be used as it is without having to separately prepare the pads 21 and 22, the polishing process can be performed more economically than in the previous embodiment. Since the polishing method using the polishing means according to the present embodiment is the same as the case of the previous embodiment described above, description thereof is omitted here.

5A and 5B show a polishing means according to another embodiment of the present invention, and Fig. 5C shows a cross section taken along the line I-I of Figs. 5A and 5B. As shown, FIGS. 4A-4C except that the polishing means in this embodiment is constructed using an insertion pad 32 smaller than the outer diameter of the insertion pad 31 in the embodiment of FIGS. 4A-4C. It is the same as the grinding means in. That is, the polishing means in this embodiment is a donut-shaped member in which the opening portion 32a is formed by removing the center portion with a predetermined radius, and the outer diameter of the polishing pad 1 is smaller than that of the polishing plate 1. Have Thus, that is, as shown in Fig. 5C, the insertion pad 32 is attached between the ordinary polishing pad 2 and the polishing plate 1. Therefore, the center portion of the polishing pad 2 is recessed into the opening 32a of the insertion pad 32 to be directly attached to the polishing plate 1, and the insertion pad 32 having a small outer diameter and the polishing plate having a large diameter are provided. Since the edge portion of the polishing pad 2 is recessed in the space where the end is formed by (1) and adheres directly to the edge portion of the polishing plate 1, the contour of the polishing pad 2 is polished in FIGS. 3A to 3C. It is made to have the same shape as the outline of the pad 22. Thus, while performing the same function as the polishing pad 22 of FIG. 3C, the polishing process can be performed more effectively than in the case of the previous embodiment, and further improved effects can be obtained. Since the polishing method using the polishing means according to the present embodiment is the same as the case of the previous embodiment described above, description thereof is omitted here.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

According to the present invention configured as described above, by intentionally reducing the contact time of the wafer edge portion with the pad is applied to the interlayer insulating film or tungsten chemical, mechanical polishing process in the semiconductor device manufacturing process to improve the wafer polishing uniformity, By extending the service life, productivity and polishing cost can be reduced.

Claims (6)

In the wafer polishing apparatus, A carrier for supporting, rotating and transporting the wafer; A polishing pad positioned at a central portion thereof and having a first depression corresponding to an edge of the wafer; And Polishing plate to rotate the polishing pad attached to the upper surface Wafer polishing apparatus comprising a. The method of claim 1, And the polishing pad includes a second recessed portion corresponding to an edge portion of the wafer at an edge portion thereof. In the wafer polishing apparatus, A carrier for supporting, rotating and transporting the wafer; Rotating abrasive plates; A donut-shaped insertion member mounted on the polishing plate and having a hole in a central portion thereof corresponding to an edge of the wafer; And A polishing pad formed on the polishing plate on which the insertion member is mounted, the polishing pad having a first depression at its center by the insertion member; Wafer polishing apparatus comprising a. The method of claim 3, wherein The insertion member is smaller than the outer diameter of the polishing plate and the polishing pad, And the polishing pad has a second recess at its edge corresponding to the edge of the wafer. A wafer using a wafer polishing apparatus comprising a carrier for supporting, rotating and transporting a wafer, a polishing pad having at least one recess corresponding to an edge of the wafer, and a polishing plate for attaching and rotating the polishing pad to an upper surface thereof In the method of polishing, Rotating the wafer and the polishing plate while the edge portion of the wafer faces the depression Wafer Polishing Method. The method of claim 5, And polishing the wafer while transferring the wafer in the radial direction of the polishing pad by using the carrier.