US20090104863A1

US20090104863A1 - Pad conditioner for chemical mechanical polishing

Info

Publication number: US20090104863A1
Application number: US11/874,175
Authority: US
Inventors: Chun-Liang Lin; Shen-Cheng Wu; Win-Sun Lin
Original assignee: United Microelectronics Corp
Current assignee: United Microelectronics Corp
Priority date: 2007-10-17
Filing date: 2007-10-17
Publication date: 2009-04-23

Abstract

A pad conditioner for chemical mechanical polishing includes a dressing component for conditioning a pad and a housing for accommodating the dressing component. The housing includes at least one fluid hole surrounding the dressing component for providing at least a fluid.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a polishing pad conditioner for chemical mechanical polishing. More particularly, the present invention relates to a polishing pad conditioner that is capable of providing a fluid for chemical mechanical polishing.
2. Description of the Prior Art
The chemical mechanical polishing process is currently widely used in the semiconductor field. In a chemical mechanical polishing process, the polishing property of the surface of the polishing pad deteriorates after a period of time because the slurry is not able to evenly disperse on the polishing pad any more. To solve the problem, the polishing pad conditioner is employed to condition the polishing pad to restore the polishing property of the surface of the polishing pad.
The conditioning property of the polishing pad conditioner usually resides in the dressing component and nowadays the dressing component is mostly composed of diamonds. Therefore, the conditioning property of the dressing component is key to the process stability and the wafer removal rate. A decent dressing component should meet the following requirements: stable wafer removal rate, properly conditioning the polishing pad, regenerating the conditioning property of the polishing pad and extending the operational life of the polishing pad.
During the chemical mechanical polishing process, slurry is usually employed to facilitate the chemical mechanical polishing. When the polishing pad conditioner conditions the polishing pad, particles brought about from the slurry and from the chemical mechanical polishing process may transfer to the dressing component during the conditioning process. After a while, the particles crystallize and attach to the dressing component, which shortens the operational life of the dressing component and causes the diamonds to come off the dressing component. Such diamonds will scratch the wafer and cause defects. This is a problem which needs to be solved.

SUMMARY OF THE INVENTION

The present invention therefore provides a polishing pad conditioner for chemical mechanical polishing. The polishing pad conditioner provides a fluid to continuously clean the dressing component for conditioning the polishing pad to avoid particles and to maintain the conditioning property of the dressing component, which can stabilize the wafer removal rate and regenerate the conditioning property of the polishing pad.
The polishing pad conditioner for chemical mechanical polishing of the present invention includes a dressing component for conditioning a pad and a housing for accommodating the dressing component. The housing includes at least one fluid hole surrounding the dressing component for providing at least one fluid.
The present invention again provides a method for polishing a substrate. The method of the present invention first provides a substrate. Then the substrate is polished by a polishing tool which is provided with at least a polishing pad and at least a polishing pad conditioner. The polishing pad conditioner includes a dressing component for conditioning a pad and a housing for accommodating the dressing component. The housing includes at least one fluid hole surrounding the dressing component for providing at least a fluid.
Because the polishing pad conditioner for chemical mechanical polishing of the present invention includes the fluid hole(s) surrounding the dressing component for providing at least a fluid, the fluid hole(s) may provide a fluid to clean the dressing component on the polishing pad conditioner for chemical mechanical polishing, which avoids the crystallization of the particles. This will maintain the conditioning property of the dressing component and help to diminish the defects on the wafer.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 illustrate various embodiments of the polishing pad conditioner of the present invention.

FIG. 5 illustrate a chemical mechanical polishing system with multiple polishing pads.

FIG. 6 illustrate a chemical mechanical polishing system with a single large-sized polishing pad.

FIG. 7 illustrates a linear chemical mechanical polishing system.

DETAILED DESCRIPTION

FIG. 1 illustrates the polishing pad conditioner of the present invention for chemical mechanical polishing. The polishing pad conditioner 100 of the present invention includes a dressing component 110 for conditioning a pad and a housing 120 for accommodating the dressing component 110. The materials for the dressing component 110 and the housing 120 are known in the field and will not be described in detail. The dressing component 110 may be a diamond bar for example. The surface of the dressing component 110 may preferably be embedded with granules of hardness between 4-10. The granules may be made of SiC, dimond, ZrO₂, Al₂O₃.
In order to clean the dressing component 110 to avoid the accumulation of the slurry and the particles, the housing 120 includes at least one fluid hole 121 surrounding the dressing component 110 for providing at least one fluid to wash away the slurry and the particles to keep the dressing component 110 clean when the fluid spurts.
The polishing pad conditioner 100 and the dressing component 110 illustrated in FIG. 1 are rectangular, but are not limited to this. For example, the polishing pad conditioner 100 and the dressing component 110 may also be in any shape, such as round or oval, i.e. the disc shape in FIG. 2, or a polygon, such as the triangle in FIG. 3. In addition, the housing 120 of the polishing pad conditioner 100 may include a plurality of parts which can be assembled together. For example, in FIG. 2, the housing 120 is composed of two pieces 120A/120B.
The size of the housing 120 depends on the size of the wafers. For example, for a system for the 8-inch wafer, the length of the housing 120 may be 31-32 cm and the width may be 6-7 cm. Besides, for a system for the 12-inch wafer, the size of the housing 120 may be about 70 cm.
Optionally, the fluid supplied by the fluid hole 121 may be liquids such as water or slurry, or gases such as air or inert gas, or the combination thereof. For example, the slurry may be supplied during the polishing process to facilitate the chemical mechanical polishing and ensure that the slurry will not dry out on the surface of the dressing component 110 of the polishing pad conditioner 100. Alternatively, water may be supplied during the conditioning of the polishing pad to clean the dressing component 110, or gas may be supplied to clean the dressing component 110. Moreover, there may be at least one fluid channel in the housing 120 of the polishing pad conditioner 100, such as the fluid channels 122A/122B illustrated in FIG. 1 to supply each of the fluid holes 121 surrounding the dressing component 110 with a fluid. The fluid channel(s) and the fluid hole(s) may also be removably attached to the housing 120 of the polishing pad conditioner 100, for example externally hung on the housing 120 of the polishing pad conditioner 100.
In order to enhance the fluid to clean the dressing component 110, the location of the fluid holes 121 can be optionally arranged so that the fluid may substantially contact the dressing component 110 when spurting from the fluid holes 121 to wash away any slurry, particle or crystal possibly attached to the dressing component 110.
To keep the dressing component 110 secure in the housing 120, the housing 120 may further include a slot 123 in a shape corresponding to the dressing component 110, as shown in FIG. 4, in addition to the conventional screws. The dressing component 110 may engage with the slot 123 of the polishing pad conditioner 100 by sliding thereinto to fix a relation position between the dressing component 110 and the housing 120. Furthermore, screws may be used to keep the dressing component 110 secure in the housing 120 to enhance the performance of the dressing component 110 and the wafer removal rate.
The polishing pad conditioner of the present invention may be employed in various chemical mechanical polishing systems. In one preferred embodiment of the present invention, the polishing pad conditioner of the present invention may be employed in a chemical mechanical polishing system with multiple polishing pads. FIG. 5 illustrates a chemical mechanical polishing system with multiple polishing pads. The chemical mechanical polishing system 500 includes a first polishing pad 510 and a second polishing pad 520. A wafer 530 is fixed on the first polishing pad 510 through the back pad 540, motivated by the rotating back pad 540 and undergoes the chemical mechanical polishing process in the presence of the slurry 550. On the other hand, the polishing pad conditioner 560 of the present invention conditions the second polishing pad 520 on which a wafer is absent. Or, on the contrary, the wafer 530 is fixed on the second polishing pad 520 through the back pad 540 and undergoes the chemical mechanical polishing process in the presence of the slurry 550. On the other hand, the polishing pad conditioner 560 of the present invention conditions the surface of the first polishing pad 510 on which a wafer is absent. By doing so, the polishing pad conditioner of the present invention may clean the slurry, particles or crystals on the surface of the dressing component of the polishing pad conditioner and conditions the surface of the polishing pad through the cleaned dressing component.
Or, in another preferred embodiment of the present invention, the polishing pad conditioner of the present invention may be employed in a chemical mechanical polishing system with a single large-sized polishing pad. FIG. 6 illustrates a chemical mechanical polishing system with a single large-sized polishing pad. The chemical mechanical polishing system 600 includes a rotary polishing pad 610. At least one wafer 620 is fixed on the polishing pad 610 through the back pad 630, motivated by the rotating back pad 630 and undergoes a chemical mechanical polishing process. Simultaneously, the polishing pad conditioner 640 of the present invention conditions the surface of the polishing pad 610 on another site. Moreover, the polishing pad conditioner of the present invention may be employed in a linear chemical mechanical polishing system, as shown in FIG. 7. The linear chemical mechanical polishing system 700 includes a polishing pad 710. A wafer 720 fixed by the back pad 630 and motivated by the rotating back pad 630 undergoes the chemical mechanical polishing process. On the other hand, the polishing pad conditioner 740 of the present invention conditions the surface of the first polishing pad 710 on another side. By doing so, the polishing pad conditioner of the present invention may clean the slurry, particles or crystals on the surface of the dressing component of the polishing pad conditioner and conditions the surface of the polishing pad through the cleaned dressing component.

EXAMPLE

The following example provides a comparison between the polishing pad conditioner of the present invention and the conventional polishing pad conditioner.
The polishing pad conditioner of the present invention and the conventional polishing pad conditioner are operated in a WCMP-5 system under identical recipes to compare the removal rate uniformity (RR_U %). The polishing pad conditioner of the present invention was operated for 8 working days. The conventional polishing pad conditioner was operated for 111 working days.
Conventional polishing pad conditioner


	Conventional polishing pad conditioner	RR_U %

	1	6.4839
	2	6.785
	3	6.0343
	4	8.093
	5	8.3594
	6	8.8052
	7	6.056
	8	7.4234
	9	14.0378
	10	5.4041
	11	6.4756
	Average	7.6325

Polishing pad conditioner of the present invention:


	Polishing pad conditioner
	of the present invention	RR_U %

	1	5.7648
	2	6.4487
	3	6.9301
	4	5.0689
	5	4.4262
	6	5.8628
	7	5.2237
	8	6.1312
	Average	5.7320

The comparison results clearly show that the novel polishing pad conditioner of the present invention indeed efficiently diminish the defects of the wafer during the chemical mechanical polishing process.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.

Claims

1. A polishing pad conditioner for chemical mechanical polishing, comprising:

a dressing component for conditioning a pad; and

a housing comprising at least one fluid hole surrounding said dressing component for providing at least one fluid for accommodating said dressing component.

2. The polishing pad conditioner for chemical mechanical polishing of claim 1, wherein said dressing component is round.

3. The polishing pad conditioner for chemical mechanical polishing of claim 2, wherein said housing comprises a plurality of parts.

4. The polishing pad conditioner for chemical mechanical polishing of claim 1, wherein said dressing component is selected from a shape of a polygon consisting of triangle and rectangular.

5. The polishing pad conditioner for chemical mechanical polishing of claim 1, wherein said housing comprises a slot for engaging with said dressing component to fix a relation position between said dressing component and said housing.

6. The polishing pad conditioner for chemical mechanical polishing of claim 1, wherein said fluid is selected from a group consisting of water and slurry.

7. The polishing pad conditioner for chemical mechanical polishing of claim 1, wherein said fluid substantially contacts said dressing component when spurting from said fluid hole.

8. The polishing pad conditioner for chemical mechanical polishing of claim 1, further comprising at least one screw to fix a relation position between said dressing component and said housing.

9. A polishing pad conditioner for chemical mechanical polishing, comprising:

a dressing component for conditioning a pad; and

a housing for accommodating said dressing component, said housing comprising at least one fluid hole surrounding said dressing component for providing at least one fluid and a slot for engaging with said dressing component to fix a relation position between said dressing component and said housing.

10. The polishing pad conditioner for chemical mechanical polishing of claim 9, wherein said dressing component is round.

11. The polishing pad conditioner for chemical mechanical polishing of claim 10, wherein said housing comprises a plurality of parts.

12. The polishing pad conditioner for chemical mechanical polishing of claim 9, wherein said dressing component is selected from a shape of a polygon consisting of triangle and rectangular.

13. The polishing pad conditioner for chemical mechanical polishing of claim 9, wherein said fluid is selected from a group consisting of water and slurry.

14. The polishing pad conditioner for chemical mechanical polishing of claim 9, wherein said fluid substantially contacts said dressing component when spurting from said fluid hole.

15. The polishing pad conditioner for chemical mechanical polishing of claim 9, further comprising at least one screw to fix a relation position between said dressing component and said housing.

16. A method for polishing a substrate, comprising:

providing a substrate; and

polishing said substrate with a polishing tool, wherein said polishing tool is provided with at least a polishing pad and at least a polishing pad conditioner, and said polishing pad conditioner includes a dressing component for conditioning a pad and a housing for accommodating said dressing component, and said housing includes at least one fluid hole surrounding said dressing component for providing at least a fluid.

17. The method of claim 16, wherein said dressing component is round.

18. The method of claim 17, wherein said housing comprises a plurality of parts.

19. The method of claim 16, wherein said dressing component is selected from a shape of a polygon consisting of triangle and rectangular.

20. The method of claim 16, wherein said housing comprises a slot for engaging with said dressing component to fix a relation position between said dressing component and said housing.

21. The method of claim 16, wherein said fluid is selected from a group consisting of water and slurry.

22. The method of claim 16, wherein said fluid substantially contacts said dressing component when spurting from said fluid hole.

23. The polishing pad conditioner for chemical mechanical polishing of claim 16, further comprising at least one screw to fix a relation position between said dressing component and said housing.