US20100216378A1

US20100216378A1 - Chemical mechanical polishing apparatus

Info

Publication number: US20100216378A1
Application number: US12/701,893
Authority: US
Inventors: Jaekwang Choi; Jin-Su Jeong; Myung-Ki Hong; Boun Yoon
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2009-02-24
Filing date: 2010-02-08
Publication date: 2010-08-26
Also published as: KR20100096459A

Abstract

Provided is a chemical mechanical polishing (CMP) apparatus. The CMP apparatus may include a polishing pad including a plurality of concave regions. These concave regions may be two-dimensionally arranged in the polishing pad in a first direction and a second direction that are not perpendicular to each other and not parallel to each other. The concave regions arranged in the first direction may have a first pitch, and the concave regions arranged in the second direction may have a second pitch equal to the first pitch.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2009-0015349, filed on Feb. 24, 2009, the entire contents of which are hereby incorporated by reference herein in it's entirety.

BACKGROUND

(i) Technical Field
The present disclosure herein relates to a semiconductor manufacturing apparatus, and more particularly, to a chemical mechanical polishing apparatus for chemically and mechanically polishing a semiconductor device.
(ii) Description of the Related Art
With the recent increasing trends toward high density and ultra-fine patterning and multi-layered interconnection line of semiconductor devices, the step height on a wafer surface has in turn likewise increased. To reduce this step height, a polishing process has been employed. As one of polishing processes, a chemical mechanical polishing (CMP) process is used. The CMP process is a polishing process in which a chemical removing process and a mechanical removing process may be mixed as a single process. In particular, the CMP process planarizes a surface of a wafer by contacting and rotating the surface of the wafer having a step height with a polishing pad and supplying slurry containing an abrasive and chemicals between the wafer and the polishing pad.

SUMMARY

The present disclosure may provide a chemical mechanical polishing apparatus with enhanced polishing efficiency.
Embodiments of the inventive concept provide chemical mechanical polishing apparatuses including a polishing pad including a plurality of concave regions, wherein the plurality of concave regions are two-dimensionally arranged in a first direction and a second direction which are not perpendicular to each other and not parallel to each other, and the concave regions arranged in the first direction have a first pitch and the concave regions arranged in the second direction have a second pitch equal to the first pitch.
In some embodiments, the above chemical mechanical polishing apparatus may further include a plurality of grooves in the polishing pad. In this case, the plurality of concave regions may be disposed between the plurality of grooves.
In other embodiments, the plurality of grooves may be disposed in the polishing pad in a curve form, a straight line form, and a combination thereof.
In still other embodiments, the plurality of concave regions may have a circular form or an elliptical form.
In even other embodiments, the spacing between the concave regions arranged in the first direction may be equal to the diameter of each of the plurality of concave regions.
In another embodiment, a chemical mechanical polishing apparatus is provided. The chemical mechanical polishing apparatus includes a polishing station which includes a polishing pad conditioner for controlling a surface state of a polishing pad during a polishing process, a slurry supply unit for supplying slurry onto a surface of the polishing pad during the polishing process and a polishing table which includes a platen and the polishing pad. The platen is configured such that the polishing station can rotate and wherein the polishing pad is disposed on the platen. The chemical mechanical polishing apparatus further includes a head assembly which includes a polishing head and a driving motor, wherein the driving motor provides power to the polishing head such that the polishing head can perform a vibrating motion, a rotating motion and a reciprocating motion, and a wafer is mountable on the polishing head for the polishing process. The polishing pad includes a plurality of concave regions and a plurality of grooves disposed in the polishing pad between the concave regions, wherein the plurality of concave regions are arranged two-dimensionally in a first direction and a second direction which are not perpendicular to each other and not parallel to each other, and the concave regions arranged in the first direction have a first pitch and the concave regions arranged in the second direction have a second pitch equal to the first pitch. The plurality of grooves partition the plurality of concave regions disposed in the polishing pad and provide a path for slurry between the polishing pad and the wafer in the polishing process.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the inventive concept can be understood in more detail from the following description, taken in conjunction with the drawings in which:

FIG. 1 is a perspective view of a chemical mechanical polishing apparatus according to an exemplary embodiment of the inventive concept;

FIG. 2 is a plan view of a chemical mechanical polishing apparatus according to an exemplary embodiment of the inventive concept;

FIG. 3 is a detailed view of region ‘A’ shown in FIG. 2;

FIG. 4 is a schematic view illustrating a chemical mechanical polishing apparatus according to an exemplary embodiment of the inventive concept;

FIG. 5 is a schematic view illustrating a chemical mechanical polishing apparatus according to an exemplary embodiment of the inventive concept; and

FIG. 6 is a schematic view illustrating a chemical mechanical polishing apparatus according to an exemplary embodiment of the inventive concept.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Exemplary embodiments of the inventive concept will be described below in more detail with reference to the accompanying drawings. The inventive concept may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will also be understood that when a layer (or film) is referred to as being ‘on’ another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. In the figures, the dimensions of layers and regions are exaggerated for clarity of illustration. Also, the representations in the accompanying drawings are schematically provided to facilitate description of the embodiments and may be different in actual form.
A chemical mechanical polishing apparatus according to an embodiment of the inventive concept will now be described with reference to FIGS. 1 through 3. FIG. 1 is a perspective view of a chemical mechanical polishing apparatus according to some embodiments of the inventive concept, FIG. 2 is a plan view illustrating one surface of a polishing pad 1400 of FIG. 1, and FIG. 3 is a detailed view of region ‘A’ of FIG. 2.
Referring to FIG. 1, the chemical mechanical polishing apparatus according to an embodiment of the inventive concept may include a polishing station 1000 and a head assembly 2000.
The polishing station 1000 may include a polishing pad conditioner 1200, a slurry supply unit 1500, and a polishing table 1100. The polishing pad conditioner 1200 may control a surface state of a polishing pad during a polishing process. For example, the polishing pad conditioner 1200 may restore the surface roughness of the polishing pad 1400 pushed during a polishing process to constantly maintain a profile of the polishing pad 1400. In addition, the polishing pad conditioner 1200 may uniformly dispense slurry particles on the polishing pad 1400 by rotating and/or reciprocating motion. The slurry supply unit 1500 may supply slurry onto a surface of the polishing pad 1400 during the polishing process.
The polishing table 1100 may include a platen 1300 and the polishing pad 1400. The platen 1300 may be configured such that the polishing station 1000 can rotate. The polishing pad 1400 may be disposed on the platen 1300.
The polishing pad 1400 may include a first surface and a second surface. The first surface may be a surface adjacent to the platen 1300 and the second surface may be a surface directed toward the head assembly 2000. In the polishing process, a polishing may be performed on a surface of a wafer W contacting the second face of the polishing pad 1400.
The head assembly 2000 may include a polishing head 2100 and a driving motor 2200. The driving motor 2200 may provide power to the polishing head 2100 such that the polishing head 2100 can perform a vibrating motion, a rotating motion and/or a reciprocating motion. A wafer W may be mounted on the polishing head 2100. The wafer W may include a polishing target surface and a mounted surface oppositely facing the polishing target surface. The mounted surface of the wafer W may be a surface mounted in the head assembly 2000. The polishing head 2100 may support the wafer W such that the polishing target surface of the wafer W faces the polishing pad 1400. That is, the polishing head 2100 may be a supporting member supporting the wafer W for the polishing process.
Referring to FIG. 3, a plurality of concave regions 1430 may be disposed in the second surface of the polishing pad 1400. The plurality of concave regions 1430 may be, for example, two-dimensionally arranged in the polishing pad 1400 in a first direction and a second direction. The first direction is not perpendicular and not parallel to the second direction. The angle θ between the first direction and the second direction may be, for example, about 60°.
For the convenience of description, the center of the first concave region 1430 a in the polishing pad 1400 is indicated by letter X, the center of a second concave region 1430 b adjacent to the first concave region 1430 a in the first direction is indicated by letter Y, and the center of a third concave region 1430 c adjacent to the first concave region 1430 a in the second direction is indicated by letter Z. The first, second and third concave regions 1430 a, 1430 b, 1430 c are any concave regions selected among the plurality of concave regions 1430 of the polishing pad 1400.
The first and second concave regions 1430 a and 1430 b arranged in the first direction may have a first pitch P1. Throughout this specification, the pitch is defined by the distance between centers of neighboring concave regions. For example, when the plurality of concave regions 1430 have a circular shape as shown in FIG. 2, the center of each of the circles becomes the center of each of the plurality of concave regions 1430.
The first and third concave regions 1430 a and 1430 c arranged in the second direction may have a second pitch P2. The second pitch P2 may be substantially equal to the first pitch P1. In one embodiment, for example, the first pitch P1 and/or the second pitch P2 may be substantially equal to the diameter of the concave region 1430. Alternatively, for example, the first pitch P1 and/or the second pitch P2 may be greater or less than the diameter of the concave region 1430.
In one embodiment, for example, lines connecting a central point of any of the plurality of concave regions 1430 and central points of the concave regions 1430 adjacent to the any of the plurality of concave regions 1430 in the first and second directions may form an equilateral triangle. That is, the pitch P1 between the first concave region 1430 a and the second concave region 1430 b, the pitch P3 between the second concave portion 1430 b and the third concave region 1430 c, and the pitch P2 between the third concave region 1430 c and the first concave region 1430 a may be substantially the same. Accordingly, lines connecting the central point X of the first concave region 1430 a, the central point Y of the second concave region 1430 b and the central point Z of the third concave region 1430 c may constitute an equilateral triangle. In one embodiment, for example, any of the plurality of concave regions 1430 may be surrounded by six concave regions 1430 arranged with the same pitch.
Due to the foregoing configuration of the concave regions 1430, a lot more concave regions 1430 may be disposed in the polishing pad 1430. For example, in the case where the concave regions 1430 are two-dimensionally arranged in the first and second direction perpendicular to each other, an area of the polishing pad 1400 where the four concave regions are disposed may be defined as X2 (where X is a distance between the central points of the concave regions and areas of the concave regions themselves are neglected). On the other hand, in the case where the concave regions 1430 are disposed according to embodiments of the inventive concept, an area of the polishing pad 1400 where the four concave regions 1430 are disposed may be defined as
$\frac{\sqrt{3}}{2} X^{2} .$
Accordingly, more concave regions 1430 may be disposed in the polishing pad 1400 having the same area.
In the CMP, the density of the concave regions 1430 in the polishing pad, e.g., the number of the concave regions 1430 per unit area may be one factor determining polishing efficiency. For example, in a polishing process, a polishing of the polishing target surface of the wafer W may be generated at contact portions between edges of the concave regions 1430 and the wafer W. Accordingly, as the number of the concave regions per unit area increases, the polishing efficiency may be enhanced. So, the polishing process, which uses the polishing pad 1400 including the concave regions 1430 according to the embodiments of the inventive concept, may have a high polishing efficiency.
The concave regions 1430 in the polishing pad 1400 may have various shapes. As one example, the concave regions 1430 may have a circular shape as shown in FIG. 3. In another example, the concave regions 1430 may have an elliptical shape as shown in FIG. 4. In the case where the concave regions 1430 have an elliptical shape as shown in FIG. 4, the center of the concave region 1430 may be defined as a point where a semimajor axis of the ellipse meets with a semiminor axis of the ellipse. Alternatively, the concave regions 1430 may have a polygonal shape, such as, for example, a rectangular shape.
In the case where the concave regions 1430 are formed in an elliptical shape, the polishing efficiency of the CMP apparatus including the concave regions 1430 can be further enhanced. For example, as described above, the polishing process using the polishing pad 1400 may include polishing the polishing target surface of the wafer W with the polishing pad 1400 including the concave regions 1430. While the polishing pad 1400 and/or the wafer W performs a rotating motion or reciprocating motion, the polishing target surface of the wafer W may be polished by friction between the wafer W and the polishing pad 1400. The friction between the edges of the concave regions 1430 and the polishing target surface of the wafer W may be one factor for performing the polishing process. In the case where the concave regions 1430 are formed in an elliptical shape and paths of the rotating motion and/or the reciprocating motion accord with or are in proximity with the semiminor axis direction of the ellipse, a contacting degree between the edges of the concave regions 1430 and the polishing target surface of the wafer W may be more elevated. Accordingly, in the case of the concave regions 1430 having the same size, the polishing efficiency can be further enhanced by forming the concave regions 1430 in an elliptical shape.
A groove 1420 may be disposed in the polishing pad 1400 between the concave regions 1430. The groove 1420 may partition the plurality of concave regions 1430 disposed in the polishing pad 1400. The groove 1420 may provide a path for slurry between the polishing pad 1400 and the wafer W in the polishing process.
The groove 1420 may be provided in various forms in the polishing pad 1400. The groove 1420 may be formed in, for example, a straight line form in the polishing pad 1400 as shown in FIG. 4. Also, the groove 1420 may be provided, for example, in plurality in the polishing pad 1400, and the plurality of grooves 1420 may meet each other at one region.
In another example, as shown in FIG. 5, a groove 1421 in a polishing pad 1401 may have a curve form. For example, the groove 1421 may have a closed curve form or open form. For example, the groove 1421 may be formed in a circular form or spiral form.
In still other examples, as shown in FIG. 6, a groove 1422 in a polishing pad 1402 may include straight line-shaped grooves 1424 and curve-shaped grooves 1423. However, the forms of the foregoing grooves 1420, 1421, 1422 may be changed into other forms than the foregoing forms.
A method of manufacturing a CMP apparatus according to an embodiment of the inventive concept will now be described with reference to FIGS. 2 and 3. The description overlapping the foregoing embodiment will be omitted.
Referring to FIGS. 2 and 3, a polishing pad 1400 is prepared. The polishing pad 1400 may include a polymer. For example, the polishing pad 1400 may include polyurethane.
Concave regions 1430 are formed in the polishing pad 1400. The concave regions 1430 may be formed by, for example, recessing selected regions of the second surface of the polishing pad 1400. The concave regions 1430 may be formed, for example, by irradiating a laser beam onto the polishing pad 1400. The selected regions are recessed by the irradiation of the laser beam, so that the concave regions 1430 may be formed in the polishing pad 1400. Alternatively, the concave regions 1430 may be formed by using, for example, a mechanical method.
The laser beam may be irradiated several times with a predetermined distance P1 in the first direction. For example, while the laser and/or the polishing pad 1400 are moved at a constant speed in parallel to each, the laser beam may be irradiated onto the second surface of the polishing pad 1400 at a constant interval. The laser and/or the polishing pad 1400 may move and stop repeatedly.
The form, pitch and the like of the concave regions 1430 may be controlled by many factors such as, for example, the moving speed of the laser and/or the polishing pad 1400, and the irradiation time interval of the laser beam. For example, the laser beam may be continuously irradiated onto the polishing pad 1400 at an irradiation time interval, and after a time longer than the irradiation time interval elapses, the laser beam may be again continuously irradiated. At this time, the polishing pad 1400 and/or the laser may be moved at a constant direction and speed. By doing so, an elliptical concave region 1430 having a semimajor axis parallel to the moving direction of the polishing pad 1400 and/or the laser may be formed.
A line connecting centers X, Y of the concave regions 1430 a, 1430 b arranged in series in the first direction may constitute a first line. In one embodiment, a pitch P1 between the concave regions 1430 a and 1430 b may be substantially equal to a diameter of the concave regions 1430 a, 1430 b. Alternatively, the pitch P1 may be greater than the diameter of the concave regions 1430 a, 1430 b.
A plurality of concave regions 1430 arranged in parallel to the first line may be formed in the polishing pad 1400. The plurality of concave regions 1430 arranged in parallel to the first line may constitute a second line. The concave regions 1430 constituting the second line may be formed with the same pitch as the pitch P1 of the concave regions 1430 a, 1430 b constituting the first line.
Any 1430 c of the plurality of concave regions 1430 constituting the second line may be formed such that distances P2 and P3 to the concave regions 1430 a and 1430 b in one pair adjacent to each other among the plurality of concave regions 1430 constituting the first line may be substantially equal to each other. That is, the distance P2 between the center X of the first concave region 1430 a and the center Z of the third concave region 1430 c may be substantially equal to the distance P3 between the center Y of the second concave region 1430 b and the center Z of the third concave region 1430 c. Also, the distance P2 between the center X of the first concave region 1430 a and the center Z of the third concave region 1430 c and the distance P3 between the center Y of the second concave region 1430 b and the center Z of the third concave region 1430 c may be substantially equal to the distance P1 between the center X of the first concave region 1430 a and the center Y of the second concave region 1430 b. By doing so, the lines connecting the centers X, Y, Z may constitute an equilateral triangle.
A groove 1420 may be formed on the polishing pad 1400 between the concave regions 1430. The groove 1420 may be formed by, for example, irradiating a laser beam along a line on the polishing pad 1400. The groove 1420 may be formed by various methods other than the foregoing method by, for example, a mechanical method.
According to the embodiments of the inventive concept, the chemical mechanical polishing apparatuses may include a polishing pad including a plurality of concave regions. The concave regions may be disposed in a shape optimized for high integration in the polishing pad. Accordingly, the polishing efficiency of the chemical mechanical polishing apparatuses including the polishing pad can be enhanced.
Having described the exemplary embodiments of the inventive concept, it is further noted that it is readily apparent to those of reasonable skill in the art that various modifications may be made without departing from the spirit and scope of the invention which is defined by the metes and bounds of the appended claims.

Claims

1. A chemical mechanical polishing apparatus comprising:

a polishing pad including a plurality of concave regions,

wherein the plurality of concave regions are two-dimensionally arranged in a first direction and a second direction which are not perpendicular to each other and not parallel to each other, and wherein

the concave regions arranged in the first direction have a first pitch and the concave regions arranged in the second direction have a second pitch equal to the first pitch.

2. The chemical mechanical polishing apparatus of claim 1, further comprising a plurality of grooves in the polishing pad, wherein the plurality of grooves partition the plurality of concave regions.

3. The chemical mechanical polishing apparatus of claim 2, wherein the plurality of grooves are disposed in the polishing pad in a curve form, a straight line form, and a combination thereof.

4. The chemical mechanical polishing apparatus of claim 1, wherein the plurality of concave regions have a circular form or an elliptical form.

5. The chemical mechanical polishing apparatus of claim 1, wherein a spacing between the concave regions arranged in the first direction is substantially equal to a diameter of each of the plurality of concave regions.

6. The chemical mechanical polishing apparatus of claim 1, further comprising:

a polishing station; and

a head assembly facing the polishing station,

wherein the polishing pad is mounted on the polishing station such that the plurality of concave regions face the head assembly.

7. The chemical mechanical polishing apparatus of claim 6, wherein the head assembly comprises a supporting member on which a wafer is mounted, and a polishing target surface of the wafer is mounted on the supporting member to face the polishing pad.

8. The chemical mechanical polishing apparatus of claim 7, further comprising a slurry supply unit supplying slurry between the wafer and the polishing pad.

9. A chemical mechanical polishing apparatus comprising:

a polishing station which includes a polishing pad conditioner for controlling a surface state of a polishing pad during a polishing process, a slurry supply unit for supplying slurry onto a surface of the polishing pad during the polishing process and a polishing table which includes a platen and the polishing pad, wherein the platen is configured such that the polishing station can rotate and wherein the polishing pad is disposed on the platen; and

a head assembly which includes a polishing head and a driving motor,

wherein the driving motor provides power to the polishing head such that the polishing head can perform a vibrating motion, a rotating motion and/or a reciprocating motion, and wherein a wafer is mountable on the polishing head for the polishing process,

wherein the polishing pad includes a plurality of concave regions and a plurality of grooves disposed in the polishing pad between the concave regions, wherein the plurality of concave regions are arranged two-dimensionally in a first direction and a second direction which are not perpendicular to each other and not parallel to each other, and

the concave regions arranged in the first direction have a first pitch and the concave regions arranged in the second direction have a second pitch equal to the first pitch, and wherein the plurality of grooves partition the plurality of concave regions disposed in the polishing pad and provide a path for slurry between the polishing pad and the wafer in the polishing process.

10. The chemical mechanical polishing apparatus of claim 9, wherein the angle between the first direction and the second direction is about 60°.

11. The chemical mechanical polishing apparatus of claim 9, wherein a spacing between the concave regions arranged in the first direction is substantially equal to a diameter of each of the plurality of concave regions.

12. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of concave regions face the head assembly.

13. The chemical mechanical polishing apparatus of claim 12, wherein the head assembly comprises a supporting member on which the wafer is mounted, and a polishing target surface of the wafer is mounted on the supporting member to face the polishing pad.

14. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of concave regions comprise a first concave region, a second concave region and a third concave region, and wherein lines connecting a central point of the first concave region, a central point of the second concave region and a central point of the third concave region forms an equilateral triangle.

15. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of concave regions have a circular shape.

16. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of concave regions have an elliptical shape.

17. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of concave regions have a rectangular shape.

18. The chemical mechanical polishing apparatus of claim 9, wherein the grooves are provided in a straight line form in the polishing pad.

19. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of grooves in the polishing pad are curved-shaped grooves.

20. The chemical mechanical polishing apparatus of claim 9, wherein the plurality of grooves in the polishing pad comprise straight line-shaped grooves and curved-shaped grooves.