JP2004160609A - Cmp device and polishing method, semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CMP device and method, a semiconductor device and its manufacturing method that inhibits deluster of a transparent film on a laser window to correctly detect its sharpening endpoint. <P>SOLUTION: This CMP device is provided with a sharpening endpoint detection mechanism detecting sharpening endpoint of a wafer being a polished substrate. It contains: a turntable 11; a polishing cloth 13 mounted on this turntable 11 pressing the wafer to be polished; the laser window 30 provided between the polishing cloth 13 and the turntable 11; the transparent film 51 installed in this laser window 30; a light emitting element irradiating laser beam on the polishing surface of the wafer through the above laser window 30 and the transparent film 51; a photodetector receiving the light reflected on the above polishing surface through the laser window 30 and the transparent film 51; and a dew condensation arresting mechanism preventing the transparent film 51 from dew condensation. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a CMP apparatus, a CMP polishing method, a semiconductor device, and a method for manufacturing the same. In particular, the present invention relates to a CMP apparatus, a CMP polishing method, a semiconductor device, and a method of manufacturing the same, which can accurately detect a polishing end point while suppressing devitrification of a transparent film of a laser window.
[0002]
[Prior art]
FIG. 3A is a plan view schematically showing a CMP (Chemical Mechanical Polishing) apparatus provided with a conventional polishing end point detection apparatus, and FIG. 3B is a 3b-3b line shown in FIG. FIG. FIG. 4 is an enlarged cross-sectional view of a part of the polishing cloth and the turntable shown in FIG.
The CMP apparatus has a disk-shaped turntable 111, and a rotary motor (not shown) is arranged on the lower surface of the turntable 111 via a rotary shaft (not shown).
[0003]
A polishing cloth 113 is placed on the upper surface of the turntable 111. A light emitting element 123 and a light receiving element (not shown) are arranged below the turntable 111. The turntable 111 and the polishing cloth 113 are provided with a laser window (hole) 120. As shown in FIG. 4, a resin transparent film 131 is provided on the laser window of the polishing cloth 113. A transparent film 132 made of resin is provided on the laser window of the turntable 111.
[0004]
When the turntable 111 rotates as shown by the arrow and the laser window 120 is positioned above the light emitting element 123, the laser light emitted by the light emitting element 123 passes above the turntable 111 through the laser window 120 and the transparent films 131 and 132. To be sent to The light emitting element 123, the light receiving element, the laser window 120 and the like constitute a polishing end point detecting device.
[0005]
Above the turntable 111, a wafer suction head 117 as a wafer holding means is arranged. Above the wafer suction head 117, a rotation motor (not shown) is arranged via a rotation shaft 118. During polishing, the wafer suction head 117 is positioned above the light emitting element 123. A nozzle (not shown) for discharging a slurry (not shown) is disposed above the turntable 111.
[0006]
A conditioner 124 is provided above the turntable 111, and the conditioner 124 is supported by an arm 125. The conditioner 124 adjusts the surface of the polishing cloth 113 after polishing a plurality of wafers or while polishing the wafers.
[0007]
When polishing a wafer as a substrate to be polished by the CMP apparatus, first, the back surface of the wafer 115 is vacuum-adsorbed to a lower portion of the wafer holding means 117. Then, the turntable 111 is rotated in the direction of the arrow shown in FIG. 3A by the rotation motor, and the slurry is discharged from the nozzle, and the slurry is dropped near the center of the polishing cloth 113. Next, the wafer holding means 117 is rotated in the direction of the arrow by the rotation motor, and the surface (polishing surface) of the wafer 115 is pressed against the polishing cloth 113. The laser light emitted by the light emitting element 123 while polishing the wafer 115 in this manner is applied to the polished surface of the wafer 115 through the laser window 120 and the transparent films 131 and 132, and the light reflected on the polished surface is irradiated with the laser light. Light is received by the light receiving element through the window 120 and the transparent films 131 and 132. The reflectance and intensity of the received light are detected, and the end point of polishing the wafer 115 is detected based on the change. The polishing of the wafer is terminated at the polishing end point.
[0008]
Further, while polishing the wafer 115, the conditioner 124 is brought into contact with the polishing cloth 113 to swing. Thereby, the surface of the polishing cloth 113 is adjusted. The adjustment of the polishing cloth by the conditioner may be performed when the wafer is not polished after the wafer is polished, not during the polishing of the wafer.
[0009]
[Problems to be solved by the invention]
In the above conventional CMP apparatus, as shown in FIG. 4, a space (gap) 133 exists between the transparent film 131 provided on the laser window of the polishing cloth 113 and the transparent film 132 provided on the laser window of the turntable 111. I do. Moisture may enter the space 133. The invasion path is a gap between the transparent film 132 and the polishing cloth 113, a gap between the turntable 111 and the polishing cloth 113, and the like. When moisture enters the space 133 through these gaps, the moisture evaporates due to frictional heat during wafer polishing and dew forms on the surfaces of the transparent films 131 and 132, thereby devitrifying the transparent film. There is. When devitrified in this way, the intensity of light irradiated on the polished surface of the wafer 115 through the laser window 120 and the intensity of light received by the light receiving element through the laser window 120 are reflected by the light reflected by the polished surface. Since the light is weakened by the films 131 and 132, the reflectance of the received light cannot be accurately detected. This makes it impossible to accurately detect the polishing end point of the wafer 115.
[0010]
The present invention has been made in consideration of the above circumstances, and has as its object to suppress a devitrification of a transparent film of a laser window and accurately detect a polishing end point, a CMP polishing method, and a semiconductor device. And a method for manufacturing the same.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, a CMP apparatus according to the present invention is a CMP apparatus including a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
Turntable,
A polishing cloth placed on the turntable and pressing and polishing the substrate to be polished,
A laser window provided on the polishing cloth and the turntable,
A transparent film installed inside this laser window,
A light emitting element that irradiates a laser beam to the polished surface of the substrate to be polished through the laser window and the transparent film,
A light-receiving element that receives light reflected by the polished surface through a laser window and a transparent film,
A condensation prevention mechanism for preventing condensation of the transparent film,
It is characterized by having.
[0012]
According to the above CMP apparatus, since the CMP apparatus is provided with the dew condensation preventing mechanism, it is possible to suppress the occurrence of dew condensation on the transparent film in the laser window. Can be suppressed. Therefore, when detecting the polishing end point, the intensity of light received by the light receiving element through the laser window and the transparent film is not reduced by the devitrified transparent film. Therefore, the reflection intensity of the received light can be detected stably, and the change in the light reflectance and the light intensity of the polished surface of the wafer can be stably measured. Thereby, the polishing end point of the substrate to be polished can be accurately detected.
[0013]
In the CMP apparatus according to the present invention, the dew condensation preventing mechanism may include a heating device.
Further, in the CMP apparatus according to the present invention, the dew condensation preventing mechanism may include a cooling device.
Further, in the CMP apparatus according to the present invention, the dew condensation preventing mechanism may include a dryer.
[0014]
A semiconductor device according to the present invention is manufactured through a step of performing CMP using the CMP apparatus.
A method of manufacturing a semiconductor device according to the present invention is characterized in that a semiconductor device is manufactured through a step of performing CMP using the CMP apparatus.
[0015]
The CMP polishing method according to the present invention is a CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
The transparent film is formed by rotating the turntable, dropping slurry on the polishing cloth, pressing the substrate to be polished against the polishing cloth and polishing the same while heating the inside of the laser window to maintain a predetermined temperature. Irradiation of laser light by a light emitting element on the polished surface of the substrate to be polished through the laser window and the transparent film while suppressing the occurrence of dew condensation on the substrate, and light reflected by the polished surface is received through the laser window and the transparent film. The end point of polishing is detected by receiving light by the element.
[0016]
According to the above-mentioned CMP polishing method, since the inside of the laser window is heated and maintained at a predetermined temperature to prevent dew condensation on the transparent film, the devitrification of the transparent film of the laser window is suppressed. Can be. Therefore, when detecting the polishing end point, the intensity of light received by the light receiving element through the laser window and the transparent film is not reduced by the devitrified transparent film. Therefore, the reflection intensity of the received light can be detected stably, and the change in the light reflectance and the light intensity of the polished surface of the wafer can be stably measured. Thereby, the polishing end point of the substrate to be polished can be accurately detected.
[0017]
The CMP polishing method according to the present invention is a CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
By rotating the turntable, dropping the slurry on the polishing cloth, pressing the substrate to be polished against the polishing cloth and polishing, while cooling the inner surface of the laser window, the inner surface of the laser window Irradiating a laser beam to the polished surface of the substrate to be polished through the laser window and the transparent film with a light emitting element while suppressing the occurrence of dew condensation on the transparent film by preferentially generating dew on the polished surface. The polishing end point is detected by receiving the reflected light through a laser window and a transparent film by a light receiving element.
[0018]
According to the above-mentioned CMP polishing method, by cooling the inner surface of the laser window, the dew condensation is preferentially generated on the inner surface of the laser window to suppress the dew condensation on the transparent film. Devitrification of the transparent film of the window can be suppressed. Therefore, the polishing end point of the substrate to be polished can be accurately detected.
[0019]
The CMP polishing method according to the present invention is a CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
The turntable is rotated, the slurry is dropped on the polishing cloth, and the substrate to be polished is pressed against the polishing cloth and polished. Irradiating a laser beam to the polished surface of the substrate to be polished by the light emitting element through the laser window and the transparent film, and receiving the light reflected by the polished surface by the light receiving element through the laser window and the transparent film while suppressing Thus, the polishing end point is detected.
[0020]
According to the above-described CMP method, dew formation on the transparent film is suppressed by setting the inside of the laser window to a dry atmosphere, so that devitrification of the transparent film of the laser window can be suppressed. Therefore, the polishing end point of the substrate to be polished can be accurately detected.
[0021]
A semiconductor device according to the present invention is manufactured through a step of polishing by the CMP polishing method.
A method of manufacturing a semiconductor device according to the present invention is characterized in that a semiconductor device is manufactured through a step of polishing by the CMP polishing method.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a partial configuration of a CMP apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view of a part of the polishing cloth and the turntable shown in FIG.
As shown in FIG. 1, the CMP apparatus 10 has a disk-shaped turntable 11, and a rotation axis (not shown) is provided on a lower surface of the turntable 11 along a turntable center axis 24. In addition, a rotation motor (not shown) is arranged via the rotation shaft.
[0023]
A polishing cloth 13 is placed on the upper surface of the turntable 11. The polishing cloth 13 includes a backing layer 20 and a cover layer 22 formed thereon. Above the turntable 11, a wafer suction head 17 as a wafer holding means is disposed. Above the wafer suction head 17, a rotation shaft 18 is arranged along the suction head central axis 26. A rotation motor (not shown) is arranged on the rotation shaft 18. The wafer suction head 17 is configured to be movable in the direction of the arrow by a moving means having a parallel moving arm 28. A nozzle (not shown) for discharging a slurry (not shown) is disposed above the turntable 11.
[0024]
A laser window (hole) 30 is provided in the turntable 11 and the polishing cloth 13, and a resin transparent film 51 is provided in the laser window 30 of the polishing cloth 13 as shown in FIG. 2. The turntable 11 has an opening below the laser window 30. For this reason, the occurrence of dew condensation on the transparent film can be reduced as compared with the conventional laser window. Further, a dew condensation preventing mechanism 52 is disposed in a portion of the turntable 11 facing the laser window.
[0025]
As the condensation prevention mechanism 52, for example, a heating device such as an electric heater may be used, or a cooling device that supplies cooling water or cooling gas into the turntable 11 to cool the inside of the laser window of the turntable 11 May be used, or a dryer for drying the inside of the laser window may be used. The dew condensation preventing mechanism 52 does not necessarily need to be disposed at the position shown in FIG. 2, and may be disposed at another position as long as the dew condensation preventing function can be exhibited.
[0026]
As shown in FIG. 1, the laser window 30 holds the wafer held by the wafer suction head 17 for a portion of the time that the turntable 11 is rotating, regardless of the parallel movement of the wafer suction head 17. 14 so that it can be seen.
A light emitting element 32 and a light receiving element (not shown) are arranged below the turntable 11. When the turntable 11 is rotated as shown by the arrow and the laser window 30 is positioned above the light emitting element 32, the laser light emitted by the light emitting element 32 is transmitted above the turntable 11 through the laser window 30 and the transparent film 51. It is supposed to be. The light emitting element 32, the light receiving element, the laser window 30, and the like constitute a polishing end point detecting device.
[0027]
Various light-emitting elements can be used as the light-emitting element 32. Various light-receiving elements can be used as long as they can receive light reflected from the polished surface of the wafer and observe the wavelength and intensity of the light. It can be used. For example, as the light emitting element 32 and the light receiving element, it is preferable to use an optical film thickness detection array, but other elements may be used, and an optical detector in which a plurality of diodes are arranged may be used. It is.
[0028]
Above the turntable 11, a conditioner 41 for conditioning the polishing cloth 13 is provided. A translation arm 42 is disposed above the conditioner 41 via a support member. The conditioner 41 is configured to be movable in the direction of the arrow by a swing mechanism having a parallel movement arm 42. The swing mechanism is a mechanism that allows the conditioner 41 to swing in a direction substantially perpendicular to the rotation direction of the polishing cloth 13.
[0029]
The swing mechanism may use a stepping motor to move the conditioner 41 as shown by an arrow, or may use another mechanism. The conditioner 41 adjusts the surface of the polishing cloth 13 after polishing a plurality of wafers or while polishing the wafers. Note that a control unit (not shown) is provided in the CMP apparatus 10, and the control unit controls a swing mechanism and controls the movement of the conditioner 41.
[0030]
When polishing the wafer 14 as a substrate to be polished by the above-described CMP apparatus, first, the back surface of the wafer 14 is vacuum-adsorbed to a lower portion of the wafer adsorption head 17. Then, the turntable 11 is rotated by a rotary motor in the direction of the arrow shown in FIG. 1 to discharge slurry from the nozzle, and the slurry is dropped near the center of the polishing cloth 13. Next, the wafer suction head 17 is rotated in the direction of the arrow by the rotating motor, the surface (polishing surface) of the wafer 14 is pressed against the polishing cloth 13, and the wafer suction head 17 applies a predetermined load from the back surface of the wafer 14 with air. (For example, 2.0 to 5.0 PSI).
[0031]
The laser light 34 emitted from the light emitting element 32 while polishing the wafer 14 in this manner is irradiated onto the polished surface of the wafer 14 through the laser window 30, and the light reflected on the polished surface is transmitted through the laser window 30 to the light receiving element. To receive light. By detecting the reflectance of the received light and the intensity of the light, the polishing end point of the wafer 14 is detected. The polishing of the wafer is terminated at the polishing end point.
[0032]
After polishing a plurality of wafers as described above, the conditioner 41 is brought into contact with the polishing cloth 13 by applying a predetermined load (for example, 3.0 to 6.0 PSI) and is oscillated. Thus, the surface of the polishing cloth 13 is adjusted. The adjustment of the polishing cloth by the conditioner is not limited to after the polishing of the wafer, but can be performed during the polishing of the wafer or when the wafer is not polished.
[0033]
By operating the dew condensation prevention mechanism 52 while the wafer is being polished as described above, dew condensation on the transparent film 51 of the laser window can be prevented.
That is, when the dew condensation preventing mechanism 52 is a heating device such as a heater, dew condensation occurs on the transparent film 51 by maintaining the inside of the laser window 30 at the same temperature as the process temperature, for example, about 50 to 60 ° C. by the heater. To prevent
[0034]
When the dew condensation prevention mechanism 52 is a cooling device, cooling water or a cooling gas is supplied into the turntable 11 to cool the inner surface of the laser window of the turntable 11 so that the inner surface of the laser window has priority. Condensation will be generated. As a result, it is possible to prevent dew condensation from occurring on the transparent film 51.
When the dew condensation preventing mechanism 52 is a dryer, the inside of the laser window is made to have a dry atmosphere by the drier, thereby preventing dew condensation on the transparent film 51.
[0035]
According to the above embodiment, since the dew condensation preventing mechanism 52 is provided in the CMP apparatus, it is possible to prevent dew formation on the transparent film 51 in the laser window. As a result, devitrification of the transparent film of the laser window can be suppressed. Therefore, when detecting the polishing end point, the intensity of light received by the light receiving element through the laser window 30 and the transparent film 51 is not reduced by the devitrified transparent film. Therefore, the reflection intensity of the received light can be detected stably, and the change in the light reflectance and the light intensity of the polished surface of the wafer can be stably measured. Thus, the polishing end point of the wafer 14 can be accurately detected.
[0036]
It should be noted that the present invention is not limited to the above embodiment, and can be implemented with various modifications without departing from the spirit of the present invention.
Further, in the above embodiment, a CMP apparatus and a CMP polishing method are described, but the present invention is not limited to these, and a semiconductor manufactured through a step of performing CMP polishing using the CMP apparatus. The present invention can also be implemented as an apparatus, or can be implemented as a method of manufacturing a semiconductor device through a step of performing CMP polishing using the CMP apparatus, and a method of manufacturing a semiconductor device. The present invention can also be implemented as a semiconductor device manufactured through a step of polishing by a CMP method, or can be implemented as a method of manufacturing a semiconductor device by manufacturing a semiconductor device through a step of polishing by the CMP polishing method. .
[Brief description of the drawings]
FIG. 1 is a sectional view showing a partial configuration of a CMP apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view of a part of the polishing cloth and the turntable shown in FIG. 1;
FIG. 3 is a schematic diagram of a CMP apparatus provided with a conventional polishing end point detecting device.
FIG. 4 is an enlarged cross-sectional view of a part of the polishing cloth and the turntable shown in FIG. 3 (b).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... CMP apparatus, 11,111 ... Turn table, 13,113 ... Polishing cloth, 14,115 ... Wafer, 17,117 ... Wafer suction head, 18,118 ... Rotating shaft, 20 ... Backing layer, 22 ... Cover layer , 24 ... turntable central axis,
26: central axis of suction head, 28: translation arm, 30, 120: laser window, 32, 123: light emitting element, 34: laser beam, 41, 124: conditioner, 42: translation arm, 51, 131, 132 ... Transparent film, 52 ... Dew prevention mechanism, 125 ... Arm

Claims (11)

In a CMP apparatus having a polishing end point detecting mechanism for detecting a polishing end point of a substrate to be polished,
Turntable,
A polishing cloth placed on the turntable and pressing and polishing the substrate to be polished,
A laser window provided on the polishing cloth and the turntable,
A transparent film installed inside this laser window,
A light emitting element that irradiates a laser beam to the polished surface of the substrate to be polished through the laser window and the transparent film,
A light-receiving element that receives light reflected by the polished surface through a laser window and a transparent film,
A condensation prevention mechanism for preventing condensation of the transparent film,
A CMP apparatus comprising: The CMP apparatus according to claim 1, wherein the dew condensation prevention mechanism has a heating device. The CMP apparatus according to claim 1, wherein the dew condensation preventing mechanism has a cooling device. The CMP apparatus according to claim 1, wherein the dew condensation preventing mechanism includes a dryer. A semiconductor device manufactured through a step of performing CMP polishing using the CMP apparatus according to claim 1. A method for manufacturing a semiconductor device, comprising: manufacturing a semiconductor device through a step of performing CMP polishing using the CMP device according to claim 1. A CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
The transparent film is formed by rotating the turntable, dropping slurry on the polishing cloth, pressing the substrate to be polished against the polishing cloth and polishing the same while heating the inside of the laser window to maintain a predetermined temperature. Irradiation of laser light by a light emitting element on the polished surface of the substrate to be polished through the laser window and the transparent film while suppressing the occurrence of dew condensation on the substrate, and light reflected by the polished surface is received through the laser window and the transparent film. A CMP polishing method characterized by detecting a polishing end point by receiving light by an element. A CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
By rotating the turntable, dropping the slurry on the polishing cloth, pressing the substrate to be polished against the polishing cloth and polishing, while cooling the inner surface of the laser window, the inner surface of the laser window Irradiating a laser beam to the polished surface of the substrate to be polished through the laser window and the transparent film with a light emitting element while suppressing the occurrence of dew condensation on the transparent film by preferentially generating dew on the polished surface. A polishing method comprising the steps of: detecting a polishing end point by receiving reflected light through a laser window and a transparent film by a light receiving element. A CMP polishing method for polishing using a CMP apparatus having a polishing end point detection mechanism for detecting a polishing end point of a substrate to be polished,
The CMP apparatus includes: a turntable; a polishing cloth mounted on the turntable; a laser window provided on the polishing cloth and the turntable; a transparent film installed in the laser window; And a light receiving element,
The turntable is rotated, the slurry is dropped on the polishing cloth, and the substrate to be polished is pressed against the polishing cloth and polished. Irradiating a laser beam to the polished surface of the substrate to be polished by the light emitting element through the laser window and the transparent film, and receiving the light reflected by the polished surface by the light receiving element through the laser window and the transparent film while suppressing A polishing end point by using the method. A semiconductor device manufactured through a step of polishing by the CMP polishing method according to claim 7. A method of manufacturing a semiconductor device, comprising: manufacturing a semiconductor device through a step of polishing by the CMP polishing method according to claim 7.

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