JP2005033012A - Polishing apparatus and semiconductor device manufacturing method - Google Patents

Abstract

An object of the present invention is to prevent moisture from entering a transparent window while ensuring a clearance when a polishing pad is arranged.
During polishing of a wafer W, dry gas is ejected from a nozzle 13 toward an opening 15, and laser light is incident on the wafer W while drying moisture that has entered the opening 15. When the reflected laser beam is received by the light receiving unit 11, the end point detection unit 12 performs end point detection.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a polishing apparatus and a method for manufacturing a semiconductor device, and is particularly suitable when applied to CMP (chemical mechanical polishing).
[0002]
[Prior art]
In the conventional polishing apparatus, there is a method of detecting the end point of CMP by providing a transparent window on the polishing pad and detecting reflected light from the wafer through the transparent window. Here, when the slurry penetrates into the polishing pad and moisture enters the transparent window provided in the polishing pad, an erroneous operation of end point detection may be caused. For this reason, for example, Patent Document 1 discloses a method of preventing slurry from penetrating into the underlayer of the polishing pad by providing a waterproof layer on the peripheral side surface of the underlayer.
[0003]
[Patent Document 1]
JP 2002-36097 A
[0004]
[Problems to be solved by the invention]
However, in order to prevent the slurry from penetrating into the undercoat layer of the polishing pad, it is necessary to completely cover the entire peripheral side surface of the undercoat layer with a waterproof layer, and there is a problem that the clearance when the polishing pad is disposed deteriorates. It was.
SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing apparatus and a semiconductor device manufacturing method capable of suppressing the intrusion of moisture into a transparent window while ensuring a clearance when a polishing pad is arranged.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, according to a polishing apparatus according to an aspect of the present invention, a polishing table, a polishing pad that is attached to the polishing table and in which layers having different hardness are stacked, and the polishing A transparent window provided in the upper layer part of the pad, an opening provided in correspondence with an arrangement position of the transparent window, provided in the lower layer part of the polishing pad, a rotating means for rotating the polishing table, and A slurry supply unit that supplies slurry onto a polishing table, a polishing head that holds the wafer on the polishing table, a light emitting unit that emits laser light to the transparent window, and a reflected light that reflects the laser light is received. A light receiving unit that performs end point detection based on a result of receiving the reflected light by the light receiving unit, and a gas ejection unit that ejects gas into the opening.
[0006]
Thus, by injecting gas into the opening, the moisture that has entered the opening can be dried, and even when the moisture that has penetrated into the polishing pad enters the opening, the moisture that has entered the opening can be removed. Can be removed. Therefore, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad, and to improve the life of the polishing pad while ensuring the clearance when the polishing pad is arranged. It becomes.
[0007]
Further, according to the polishing apparatus according to one aspect of the present invention, the polishing table, the polishing pad attached to the polishing table and laminated with layers having different hardness, and the upper layer portion of the polishing pad are provided. A transparent window, an opening provided in a lower layer portion of the polishing pad, corresponding to the position of the transparent window, a rotating means for rotating the polishing table, and supplying slurry onto the polishing table. A slurry supply means, a polishing head that holds the wafer on the polishing table, a light emitting unit that emits laser light to the transparent window, a light receiving unit that receives reflected light reflected by the laser light, and the light receiving unit An end point detecting means for detecting an end point based on a result of receiving the reflected light by the unit, and a polymer absorber disposed around the opening are provided.
[0008]
Thereby, by disposing the polymer absorber around the opening, it is possible to absorb the moisture that has entered the opening, and even when the moisture that has penetrated into the polishing pad enters the opening, the opening It is possible to remove moisture that has penetrated into. Therefore, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad, and to improve the life of the polishing pad while ensuring the clearance when the polishing pad is arranged. It becomes.
[0009]
Further, according to the polishing apparatus according to one aspect of the present invention, the polishing table, the polishing pad attached to the polishing table and laminated with layers having different hardness, and the upper layer portion of the polishing pad are provided. A transparent window, an opening provided in a lower layer portion of the polishing pad, corresponding to the position of the transparent window, a rotating means for rotating the polishing table, and supplying slurry onto the polishing table. A slurry supply means, a polishing head that holds the wafer on the polishing table, a light emitting unit that emits laser light to the transparent window, a light receiving unit that receives reflected light reflected by the laser light, and the light receiving unit An end point detecting means for detecting an end point based on a result of receiving the reflected light by the unit, and a sealing material applied to a side wall of the opening are provided.
[0010]
Thus, by applying the sealing material to the sidewall of the opening, even when moisture penetrates into the polishing pad, it is possible to prevent the moisture that has penetrated into the polishing pad from entering the opening. Therefore, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad, and to improve the life of the polishing pad while ensuring the clearance when the polishing pad is arranged. It becomes.
[0011]
Further, according to the polishing apparatus according to one aspect of the present invention, the polishing table, the polishing pad attached to the polishing table and laminated with layers having different hardness, and the upper layer portion of the polishing pad are provided. A transparent window, an opening provided in a lower layer portion of the polishing pad, corresponding to the position of the transparent window, a rotating means for rotating the polishing table, and supplying slurry onto the polishing table. A slurry supply means, a polishing head that holds the wafer on the polishing table, a light emitting unit that emits laser light to the transparent window, a light receiving unit that receives reflected light reflected by the laser light, and the light receiving unit An end point detecting means for detecting an end point based on a result of receiving the reflected light by the unit, and a transparent member filled in the opening are provided.
[0012]
Thus, by filling the opening with the transparent member, even when moisture penetrates into the polishing pad, the moisture penetrated into the polishing pad can be prevented from entering the opening. Therefore, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad, and to improve the life of the polishing pad while ensuring the clearance when the polishing pad is arranged. It becomes.
[0013]
Further, according to the polishing apparatus according to one aspect of the present invention, the polishing table, the polishing pad attached to the polishing table and laminated with layers having different hardness, and the upper layer portion of the polishing pad are provided. A transparent window, an opening provided in a lower layer portion of the polishing pad, corresponding to the position of the transparent window, a rotating means for rotating the polishing table, and supplying slurry onto the polishing table. A slurry supply means, a polishing head that holds the wafer on the polishing table, a light emitting unit that emits laser light to the transparent window, a light receiving unit that receives reflected light reflected by the laser light, and the light receiving unit An end point detecting means for detecting an end point based on a result of receiving the reflected light by the unit, and a heating element for heating the inside of the opening are provided.
[0014]
Thus, the moisture that has entered the opening can be evaporated by heating the inside of the opening, and even when the water that has penetrated into the polishing pad enters the opening, the moisture that has entered the opening is removed. be able to. Therefore, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad, and to improve the life of the polishing pad while ensuring the clearance when the polishing pad is arranged. It becomes.
[0015]
In addition, according to the method for manufacturing a semiconductor device of one aspect of the present invention, the semiconductor wafer is polished while the inside of the opening provided in the polishing pad is dried to transmit the laser light, and the semiconductor wafer And a step of detecting an end point based on the reflection result of the laser beam from the laser beam.
As a result, even when moisture that has penetrated into the polishing pad enters the opening, it is possible to remove the moisture that has penetrated into the opening, allowing the moisture to penetrate into the polishing pad, and detecting the end point. It becomes possible to prevent malfunction.
[0016]
In addition, according to the method for manufacturing a semiconductor device of one embodiment of the present invention, the step of polishing the semiconductor wafer while absorbing moisture that has entered the opening provided in the polishing pad so as to transmit the laser light. And a step of detecting an end point based on a reflection result of the laser light from the semiconductor wafer.
As a result, even when moisture that has penetrated into the polishing pad enters the opening, the moisture that has entered the opening can be absorbed, allowing the moisture to penetrate into the polishing pad and detecting the end point. It becomes possible to prevent malfunction.
[0017]
In addition, according to the method for manufacturing a semiconductor device according to one aspect of the present invention, moisture that has permeated the polishing pad is prevented from entering the opening provided in the polishing pad in order to transmit laser light. And polishing the semiconductor wafer, and detecting the end point based on the reflection result of the laser beam from the semiconductor wafer.
[0018]
Thereby, even when moisture penetrates into the polishing pad, it is possible to prevent moisture penetrated into the polishing pad from entering the opening, while allowing moisture to penetrate into the polishing pad, It becomes possible to prevent malfunction of end point detection.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a polishing apparatus according to an embodiment of the present invention will be described with reference to the drawings.
1A is a cross-sectional view showing a schematic configuration of the polishing apparatus according to the first embodiment of the present invention, FIG. 1B is a plan view showing an enlarged portion of the transparent window 14 of the polishing pad 2, FIG.1 (c) is sectional drawing cut | disconnected by the AA line of FIG.1 (b).
[0020]
In FIG. 1, a polishing table (also referred to as a platen) 1 is coupled to a rotating shaft 3 so as to be rotatable about the rotating shaft 3, and a polishing pad (also referred to as a polishing cloth) is provided on the polishing table 1. 2 is pasted. Here, the polishing pad 2 can have a laminated structure including layers having different hardnesses. For example, the hard layer 2b can be laminated on the soft layer 2a via the adhesive layer 2c.
[0021]
On the polishing table 1 to which the polishing pad 2 is attached, a retainer ring 4 for guiding the periphery of the wafer W is provided, and a polishing head 5 for pressing the wafer W and the retainer ring 4 onto the polishing pad 2 is provided. Is provided. A membrane 7 for adjusting the pressure of the wafer W is inserted between the polishing head 5 and the wafer W. The membrane 7 can be made of rubber or the like, for example. Examples of the wafer W to be polished include semiconductor wafers and glass wafers on which wiring layers such as Al, Cu, and polycrystalline silicon, and insulating layers such as silicon oxide films and silicon nitrogen films are formed. Can do.
[0022]
The polishing head 5 is coupled to the spindle 6 and is configured to rotate around the spindle 6 while pressing the wafer W and the retainer ring 4 on the polishing pad 2. Above the polishing table 1, a nozzle 8 that discharges an abrasive slurry 9 onto the polishing pad 2 is provided.
As the abrasive slurry 8, for example, fumed silica-based slurry or ceria-based slurry can be used when performing CMP of an interlayer insulating film such as a silicon oxide film, and wiring metal such as W, Cu, and Al can be used. When performing this CMP, for example, an alumina-based slurry mixed with an oxidizing agent can be used.
[0023]
Under the polishing table 1, a light emitting unit 10 that emits laser light toward the wafer W and a light receiving unit 11 that receives the laser light reflected from the wafer W are provided, and the light receiving unit 11 receives the laser light. An end point detector 12 for detecting an end point at the time of polishing the wafer W based on the result is provided. In addition, as an end point detection method in the end point detection part 12, the infrared interference end point detection method (end point detection by infrared interferometry) can be used, for example.
[0024]
The polishing table 1 is provided with an opening 16 through which laser light passes, and the soft layer 2a of the polishing pad 2 is provided with an opening 15 through which laser light passes, so that the hard layer 2b of the polishing pad 2 Is provided with a transparent window 14 for transmitting laser light. Further, below the polishing table 1, a nozzle 13 for injecting dry gas into an opening 15 provided in the soft layer 2 a of the polishing pad 2 is disposed. As the dry gas, for example, dry air or dry nitrogen can be used.
[0025]
Then, when polishing the wafer W, the polishing pad 2 is stuck on the polishing table 1, and the abrasive slurry 9 is discharged onto the polishing pad 2. The retainer ring 4 and the wafer W are pressed onto the polishing pad 2 by the polishing head 5, and the polishing table 1 and the polishing head 5 are rotated while guiding the periphery of the wafer W with the retainer ring 4.
[0026]
Here, by providing the polishing pad 2 with the hard layer 2b, it is possible to improve the leveling of the step and improve the flatness during polishing, and by providing the polishing pad 2 with the soft layer 2a. In addition, it is possible to absorb the warpage of the entire wafer W, and to improve in-plane uniformity during polishing.
During polishing of the wafer W, the laser light emitted from the light emitting unit 10 is incident on the wafer W through the openings 15 and 16 and the transparent window 14. Then, the laser beam reflected from the wafer W is received by the light receiving unit 11, and the end point detection unit 12 performs end point detection. Here, when the abrasive slurry 9 is discharged onto the polishing pad 2, the moisture of the abrasive slurry 9 penetrates into the polishing pad 2, and the moisture that has penetrated into the polishing pad 2 enters the opening 15. For this reason, when laser light is incident on the wafer W, dry gas is ejected from the nozzle 13 toward the opening 15 to dry the moisture that has entered the opening 15. When the end point is detected by the end point detector 12, the rotation of the polishing table 1 and the polishing head 5 is stopped, and the polishing of the wafer W is ended.
[0027]
Thereby, even when the water permeated into the polishing pad 2 enters the opening 15, the water that has entered the opening 15 can be removed. For this reason, it becomes possible to prevent malfunction of end point detection while allowing moisture to permeate into the polishing pad 2, and to improve the life of the polishing pad 2 while ensuring the clearance when the polishing pad 2 is arranged. It becomes possible.
[0028]
2A is a sectional view showing a schematic configuration of a polishing apparatus according to a second embodiment of the present invention, FIG. 2B is a plan view showing an enlarged portion of a transparent window 34 of the polishing pad 22, FIG.2 (c) is sectional drawing cut | disconnected by the BB line of FIG.2 (b).
In FIG. 2, the polishing table 21 is coupled to a rotation shaft 23 so as to be rotatable about the rotation shaft 23, and a polishing pad 22 is attached on the polishing table 21. Here, the polishing pad 22 can have a laminated structure including layers having different hardnesses. For example, the hard layer 22b can be laminated on the soft layer 22a via the adhesive layer 22c.
[0029]
A retainer ring 24 that guides the periphery of the wafer W is provided on the polishing table 21 to which the polishing pad 22 is attached, and a polishing head 25 that presses the wafer W and the retainer ring 24 onto the polishing pad 22. Is provided. Further, a membrane 27 for adjusting the pressure of the wafer W is inserted between the polishing head 25 and the wafer W.
[0030]
The polishing head 25 is coupled to the spindle 26 and is configured to rotate around the spindle 26 while pressing the wafer W and the retainer ring 24 onto the polishing pad 22. In addition, a nozzle 28 for discharging an abrasive slurry 29 onto the polishing pad 22 is provided above the polishing table 21.
Under the polishing table 21, a light emitting unit 30 that emits laser light toward the wafer W and a light receiving unit 31 that receives the laser light reflected from the wafer W are provided, and the light receiving unit 31 receives the laser light. An end point detection unit 32 that detects an end point at the time of polishing the wafer W based on the result is provided.
[0031]
The polishing table 21 is provided with an opening 36 through which laser light passes, and the soft layer 22a of the polishing pad 22 is provided with an opening 35 through which laser light passes, so that the hard layer 22b of the polishing pad 22 Is provided with a transparent window 34 for transmitting laser light.
Further, a polymer absorber (water absorbent polymer) 33 for absorbing moisture is disposed around the opening 35. Here, when the polymer absorber 33 is disposed around the opening 35, it is preferable to dispose the polymer absorber 33 at a position that does not hinder the passage of laser light when the polymer absorber 33 expands due to moisture absorption. Moreover, it is preferable to set the thickness of the polymer absorber 33 so as not to exceed the thickness of the soft layer 22a when the polymer absorber 33 expands due to moisture absorption.
[0032]
The polymer absorber 33 can absorb water several hundred to 1000 times its own weight. Examples of the polymer absorber 33 include starch-polyacrylonitrile hydrolyzate, starch-polyacrylate cross-linked product, carboxyl A methyl cellulose, a saponified product of vinyl acetate-methyl acrylate copolymer, a cross-linked product of sodium polyacrylate, or the like can be used.
[0033]
Then, when polishing the wafer W, the polishing pad 22 is attached on the polishing table 21, and an abrasive slurry 29 is discharged onto the polishing pad 22. Then, the retainer ring 24 and the wafer W are pressed onto the polishing pad 22 by the polishing head 25, and the polishing table 21 and the polishing head 25 are rotated while guiding the periphery of the wafer W with the retainer ring 24.
[0034]
During the polishing of the wafer W, the laser light emitted from the light emitting unit 30 is incident on the wafer W through the openings 35 and 36 and the transparent window 34. Then, the laser beam reflected from the wafer W is received by the light receiving unit 31, and the end point detection unit 32 performs end point detection. Here, when the abrasive slurry 29 is discharged onto the polishing pad 22, the moisture of the abrasive slurry 29 penetrates into the polishing pad 22, and the moisture that has penetrated into the polishing pad 22 enters the opening 35. The moisture that has entered the opening 35 is absorbed by the polymer absorber 33 disposed around the opening 35. When the end point is detected by the end point detector 32, the rotation of the polishing table 21 and the polishing head 25 is stopped, and the polishing of the wafer W is ended.
[0035]
Thereby, even when the water that has penetrated into the polishing pad 21 enters the opening 35, the water that has entered the opening 35 can be removed. For this reason, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad 21, and to improve the life of the polishing pad 21 while ensuring a clearance when the polishing pad 21 is arranged. It becomes possible.
[0036]
FIG. 3A is a cross-sectional view showing a schematic configuration of a polishing apparatus according to a third embodiment of the present invention, and FIG. 3B is a plan view showing an enlarged transparent window 54 portion of the polishing pad 42. FIG.3 (c) is sectional drawing cut | disconnected by CC line of FIG.3 (b).
In FIG. 3, the polishing table 41 is coupled to a rotation shaft 43 so as to be rotatable about the rotation shaft 43, and a polishing pad 42 is attached on the polishing table 41. Here, the polishing pad 42 can have a laminated structure including layers having different hardnesses. For example, the hard layer 42b can be laminated on the soft layer 42a via the adhesive layer 42c.
[0037]
A retainer ring 44 that guides the periphery of the wafer W is provided on the polishing table 41 to which the polishing pad 42 is attached, and a polishing head 45 that presses the wafer W and the retainer ring 44 onto the polishing pad 42. Is provided. A membrane 47 for adjusting the pressure of the wafer W is inserted between the polishing head 45 and the wafer W.
[0038]
The polishing head 45 is coupled to the spindle 46 and is configured to rotate around the spindle 46 while pressing the wafer W and the retainer ring 44 on the polishing pad 42. In addition, a nozzle 48 that discharges an abrasive slurry 49 onto the polishing pad 42 is provided above the polishing table 41.
Under the polishing table 41, a light emitting unit 50 that emits laser light toward the wafer W and a light receiving unit 51 that receives the laser light reflected from the wafer W are provided, and the light receiving unit 51 receives the laser light. An end point detector 52 for detecting an end point at the time of polishing the wafer W based on the result is provided.
[0039]
The polishing table 41 is provided with an opening 56 through which laser light passes, and the soft layer 42a of the polishing pad 42 is provided with an opening 55 through which laser light passes, so that the hard layer 42b of the polishing pad 42 Is provided with a transparent window 54 that transmits laser light. In addition, a sealing material 53 is applied to the side wall of the opening 55 to prevent moisture that has penetrated into the polishing pad 42 from leaking into the opening 55. In addition, as the sealing material 53, a silicone type sealing agent etc. can be used, for example.
[0040]
Then, when polishing the wafer W, the polishing pad 42 is attached on the polishing table 41, and an abrasive slurry 49 is discharged onto the polishing pad 42. Then, the retainer ring 44 and the wafer W are pressed onto the polishing pad 42 by the polishing head 45, and the polishing table 41 and the polishing head 45 are rotated while guiding the periphery of the wafer W with the retainer ring 44. Here, when the abrasive slurry 49 is discharged onto the polishing pad 42, moisture of the abrasive slurry 49 penetrates into the polishing pad 42.
[0041]
During polishing of the wafer W, the laser light emitted from the light emitting unit 50 is incident on the wafer W through the openings 55 and 56 and the transparent window 54. The laser beam reflected from the wafer W is received by the light receiving unit 51, and the end point detection unit 52 performs end point detection. When the end point is detected by the end point detection unit 52, the rotation of the polishing table 41 and the polishing head 45 is stopped, and the polishing of the wafer W is ended.
[0042]
Here, since the sealing material 53 is applied to the side wall of the opening 55, even when moisture penetrates into the polishing pad 42, the moisture that has penetrated into the polishing pad 42 penetrates into the opening 55. Can be prevented. For this reason, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad 42, and to improve the life of the polishing pad 42 while ensuring a clearance when the polishing pad 42 is disposed. It becomes possible.
[0043]
4A is a cross-sectional view showing a schematic configuration of a polishing apparatus according to a fourth embodiment of the present invention, FIG. 4B is a plan view showing an enlarged transparent window 74 portion of the polishing pad 62, and FIG. FIG.4 (c) is sectional drawing cut | disconnected by the DD line | wire of FIG.4 (b).
In FIG. 4, the polishing table 61 is coupled to a rotating shaft 63 so as to be rotatable about the rotating shaft 63, and a polishing pad 62 is attached on the polishing table 61. Here, the polishing pad 62 can have a laminated structure including layers having different hardnesses. For example, the hard layer 62b can be laminated on the soft layer 62a via the adhesive layer 62c.
[0044]
A retainer ring 64 for guiding the periphery of the wafer W is provided on the polishing table 61 to which the polishing pad 62 is attached, and a polishing head 65 for pressing the wafer W and the retainer ring 64 on the polishing pad 62 is provided. Is provided. A membrane 67 for adjusting the pressure of the wafer W is inserted between the polishing head 65 and the wafer W.
[0045]
The polishing head 65 is coupled to the spindle 66 and is configured to be able to rotate around the spindle 66 while pressing the wafer W and the retainer ring 64 on the polishing pad 62. In addition, a nozzle 68 for discharging an abrasive slurry 69 onto the polishing pad 62 is provided above the polishing table 61.
Under the polishing table 61, a light emitting unit 70 that emits laser light toward the wafer W and a light receiving unit 71 that receives the laser light reflected from the wafer W are provided, and the light receiving unit 71 receives the laser light. An end point detector 72 for detecting an end point at the time of polishing the wafer W based on the result is provided.
[0046]
The polishing table 61 is provided with an opening 76 through which laser light passes, and the soft layer 62a of the polishing pad 62 is provided with an opening 75 through which laser light passes, so that the hard layer 62b of the polishing pad 62 has Is provided with a transparent window 74 that transmits laser light.
The opening 75 is filled with a transparent member 73 for preventing moisture that has penetrated the polishing pad 62 from leaking into the opening 75. In addition, as the transparent member 73, for example, a transparent resin such as acrylic resin, polycarbonate, polyvinyl chloride, polyvinylidene fluoride, polyethersulfone, polystyrene, polyethylene, or polytetrafluoroethylene can be used.
[0047]
Then, when polishing the wafer W, a polishing pad 62 is attached on the polishing table 61, and an abrasive slurry 69 is discharged onto the polishing pad 62. Then, the retainer ring 64 and the wafer W are pressed onto the polishing pad 62 by the polishing head 65, and the polishing table 61 and the polishing head 65 are rotated while guiding the periphery of the wafer W with the retainer ring 64. Here, when the abrasive slurry 69 is discharged onto the polishing pad 62, moisture of the abrasive slurry 69 penetrates into the polishing pad 62.
[0048]
Then, during polishing of the wafer W, the laser light emitted from the light emitting unit 70 is incident on the wafer W through the opening 76, the transparent member 73, and the transparent window 74. The laser beam reflected from the wafer W is received by the light receiving unit 71, and the end point detection unit 72 performs end point detection. When the end point is detected by the end point detector 72, the rotation of the polishing table 61 and the polishing head 65 is stopped, and the polishing of the wafer W is ended.
[0049]
Here, since the opening 75 is filled with the transparent member 73, even when moisture penetrates into the polishing pad 62, the moisture that has penetrated into the polishing pad 62 enters the opening 75. Can be blocked. For this reason, it is possible to prevent malfunction of end point detection while allowing moisture to penetrate into the polishing pad 62, and to improve the life of the polishing pad 62 while ensuring a clearance when the polishing pad 62 is disposed. It becomes possible.
[0050]
FIG. 5A is a sectional view showing a schematic configuration of a polishing apparatus according to a fifth embodiment of the present invention, FIG. 5B is a plan view showing an enlarged portion of a transparent window 94 of the polishing pad 82, FIG.5 (c) is sectional drawing cut | disconnected by the EE line | wire of FIG.5 (b).
In FIG. 5, a polishing table 81 is coupled to a rotation shaft 83 so as to be rotatable about the rotation shaft 83, and a polishing pad 82 is affixed on the polishing table 81. Here, the polishing pad 82 can have a laminated structure including layers having different hardnesses. For example, the hard layer 82b can be laminated on the soft layer 82a via the adhesive layer 82c.
[0051]
Further, a retainer ring 84 for guiding the periphery of the wafer W is provided on the polishing table 81 to which the polishing pad 82 is attached, and a polishing head 85 for pressing the wafer W and the retainer ring 84 on the polishing pad 82 is provided. Is provided. Further, a membrane 87 for adjusting the pressure of the wafer W is inserted between the polishing head 85 and the wafer W.
[0052]
The polishing head 85 is coupled to the spindle 86 and is configured to be able to rotate around the spindle 86 while pressing the wafer W and the retainer ring 84 on the polishing pad 82. Above the polishing table 81, a nozzle 88 that discharges an abrasive slurry 89 onto the polishing pad 82 is provided.
Under the polishing table 81, a light emitting unit 90 that emits laser light toward the wafer W and a light receiving unit 91 that receives the laser light reflected from the wafer W are provided, and the light receiving unit 91 receives the laser light. An end point detection unit 92 that detects an end point at the time of polishing the wafer W based on the result is provided.
[0053]
The polishing table 81 is provided with an opening 96 through which laser light passes, and the soft layer 82a of the polishing pad 82 is provided with an opening 95 through which laser light passes, so that the hard layer 82b of the polishing pad 82 Is provided with a transparent window 94 for transmitting laser light. Further, a heater 93 for heating the inside of the opening 95 provided in the soft layer 82 a of the polishing pad 82 is disposed in the opening 96 of the polishing table 81. The heater 93 is connected to a temperature control unit 97 that controls the temperature of the heater 93.
[0054]
When the wafer W is polished, a polishing pad 82 is attached on the polishing table 81, and an abrasive slurry 89 is discharged onto the polishing pad 82. The retainer ring 84 and the wafer W are pressed onto the polishing pad 82 by the polishing head 85, and the polishing table 81 and the polishing head 85 are rotated while guiding the periphery of the wafer W with the retainer ring 84.
[0055]
Then, during polishing of the wafer W, the laser light emitted from the light emitting unit 90 is incident on the wafer W through the openings 95 and 96 and the transparent window 94. Then, the laser beam reflected from the wafer W is received by the light receiving unit 91, and the end point detection unit 92 performs end point detection. Here, when the abrasive slurry 89 is discharged onto the polishing pad 82, the moisture of the abrasive slurry 89 penetrates into the polishing pad 82, and the moisture that has penetrated into the polishing pad 82 enters the opening 95. For this reason, when the laser beam is incident on the wafer W, the heater 93 is turned on to heat the inside of the opening 95 and the moisture that has entered the opening 95 is evaporated. When the end point is detected by the end point detector 92, the rotation of the polishing table 81 and the polishing head 85 is stopped, and the polishing of the wafer W is ended.
[0056]
Thereby, even when the water permeated into the polishing pad 82 enters the opening 95, the water that has entered the opening 95 can be removed. For this reason, it is possible to prevent malfunction of end point detection while allowing moisture to permeate into the polishing pad 82, and to improve the life of the polishing pad 82 while ensuring a clearance when the polishing pad 82 is disposed. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a polishing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a schematic configuration of a polishing apparatus according to a second embodiment of the present invention.
FIG. 3 is a diagram showing a schematic configuration of a polishing apparatus according to a third embodiment of the present invention.
FIG. 4 is a diagram showing a schematic configuration of a polishing apparatus according to a fourth embodiment of the present invention.
FIG. 5 is a diagram showing a schematic configuration of a polishing apparatus according to a fifth embodiment of the present invention.
[Explanation of symbols]
W wafer, 1, 21, 41, 61, 81 Polishing table, 2, 22, 42, 62, 82 Polishing pad, 2a, 22a, 42a, 62a, 82a Soft layer, 2b, 22b, 42b, 62b, 82b Hard layer 2c, 22c, 42c, 62c, 82c Adhesive layer 3, 23, 43, 63, 83 Rotating shaft 4, 24, 44, 64, 84 Retainer ring 5, 25, 45, 65, 85 Polishing head, 6 26, 46, 66, 86 Spindle, 7, 27, 47, 67, 87 Membrane, 8, 13, 28, 48, 68, 88 Nozzle, 9, 29, 49, 69, 89 Abrasive slurry, 10, 30 , 50, 70, 90 Light emitting part, 11, 31, 51, 71, 91 Light receiving part, 12, 32, 52, 72, 92 End point detecting part, 14, 34, 54, 74, 94 Transparent window, 15, 16, 3 , 36,55,56,76,95,96 opening 33 polymer absorber, 53 sealing material, 73 a transparent member, 93 heating elements, 97 temperature control unit

Claims (8)

A polishing table;
A polishing pad affixed on the polishing table and laminated with different layers of hardness;
A transparent window provided in the upper layer of the polishing pad;
Arranged corresponding to the position of the transparent window, and an opening provided in a lower layer of the polishing pad;
Rotating means for rotating the polishing table;
Slurry supply means for supplying slurry onto the polishing table;
A polishing head for holding the wafer on the polishing table;
A light emitting unit for emitting laser light to the transparent window;
A light receiving unit that receives reflected light from which the laser light is reflected;
End point detection means for performing end point detection based on the light reception result of the reflected light by the light receiving unit;
A polishing apparatus comprising: gas jetting means for jetting gas into the opening. A polishing table;
A polishing pad affixed on the polishing table and laminated with different layers of hardness;
A transparent window provided in the upper layer of the polishing pad;
Arranged corresponding to the position of the transparent window, and an opening provided in a lower layer of the polishing pad;
Rotating means for rotating the polishing table;
Slurry supply means for supplying slurry onto the polishing table;
A polishing head for holding the wafer on the polishing table;
A light emitting unit for emitting laser light to the transparent window;
A light receiving unit that receives reflected light from which the laser light is reflected;
End point detection means for performing end point detection based on the light reception result of the reflected light by the light receiving unit;
A polishing apparatus comprising: a polymer absorber disposed around the opening. A polishing table;
A polishing pad affixed on the polishing table and laminated with different layers of hardness;
A transparent window provided in the upper layer of the polishing pad;
Arranged corresponding to the position of the transparent window, and an opening provided in a lower layer of the polishing pad;
Rotating means for rotating the polishing table;
Slurry supply means for supplying slurry onto the polishing table;
A polishing head for holding the wafer on the polishing table;
A light emitting unit for emitting laser light to the transparent window;
A light receiving unit that receives reflected light from which the laser light is reflected;
End point detection means for performing end point detection based on the light reception result of the reflected light by the light receiving unit;
A polishing apparatus comprising: a sealing material applied to a side wall of the opening. A polishing table;
A polishing pad affixed on the polishing table and laminated with different layers of hardness;
A transparent window provided in the upper layer of the polishing pad;
Arranged corresponding to the position of the transparent window, and an opening provided in a lower layer of the polishing pad;
Rotating means for rotating the polishing table;
Slurry supply means for supplying slurry onto the polishing table;
A polishing head for holding the wafer on the polishing table;
A light emitting unit for emitting laser light to the transparent window;
A light receiving unit that receives reflected light from which the laser light is reflected;
End point detection means for performing end point detection based on the light reception result of the reflected light by the light receiving unit;
A polishing apparatus comprising: a transparent member filled in the opening. A polishing table;
A polishing pad affixed on the polishing table and laminated with different layers of hardness;
A transparent window provided in the upper layer of the polishing pad;
Arranged corresponding to the position of the transparent window, and an opening provided in a lower layer of the polishing pad;
Rotating means for rotating the polishing table;
Slurry supply means for supplying slurry onto the polishing table;
A polishing head for holding the wafer on the polishing table;
A light emitting unit for emitting laser light to the transparent window;
A light receiving unit that receives reflected light from which the laser light is reflected;
End point detection means for performing end point detection based on the light reception result of the reflected light by the light receiving unit;
A polishing apparatus comprising: a heating element for heating the inside of the opening. Polishing the semiconductor wafer while drying the inside of the opening provided in the polishing pad to transmit the laser beam;
And a step of detecting an end point based on a reflection result of the laser beam from the semiconductor wafer. Polishing the semiconductor wafer while absorbing moisture that has penetrated into the openings provided in the polishing pad to transmit the laser light; and
And a step of detecting an end point based on a reflection result of the laser beam from the semiconductor wafer. Polishing the semiconductor wafer while preventing moisture penetrating the polishing pad from entering the opening provided in the polishing pad to transmit laser light; and
And a step of detecting an end point based on a reflection result of the laser beam from the semiconductor wafer.

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