JP2002170800A - Polishing apparatus, method for manufacturing semiconductor device using the same and semiconductor device manufactured by this method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably and easily perform optical polishing endpoint detection without causing a problem of flowing of a slurry. SOLUTION: A polishing apparatus comprises a wafer holding device 10 for holding a wafer W with the surface WUS to be polished upward and a pad holding device 20 arranged above the device 10 to hold a polishing pad 25 with the polishing surface downward, wherein the polishing surface of the pad 25 is relatively moved while the polishing surface is abutted on the surface WUS of the wafer W from an upper part to polish the surface to be polished. In this apparatus, an optical measuring device 40 is provided on the device 20 to optically measure a state of the surface WUS of the wafer W from the upper part through measuring openings 27 formed on the pad 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor manufacturing apparatus for manufacturing a semiconductor device (semiconductor wafer), and more particularly to a polishing apparatus which is implemented in a process for manufacturing a semiconductor wafer and performs flattening and polishing of the semiconductor wafer.

[0002]

2. Description of the Related Art A polishing apparatus for flattening and polishing a semiconductor wafer is conventionally known. As a conventional polishing device,
For example, as disclosed in U.S. Pat. No. 5,830,045, a polishing pad member supported on a spindle shaft is used, and a polishing agent (slurry) is supplied to the pad surface (polishing surface) of the polishing pad while the polishing pad is polished. There is a polishing apparatus that presses a held semiconductor wafer from above and rotates the pad and the wafer in the same or opposite directions to polish the wafer (CMP polishing).

In such a semiconductor wafer polishing apparatus, the control of the polishing amount is very important, and an apparatus for detecting the completion of polishing is provided. For example, the polishing completion detecting device may be a film (SiO ₂₎ formed on the surface of a wafer to be polished.
The laser beam for detection applied to the film or the like and the reference laser beam applied to the base film or substrate of this film interfere with each other to detect the polishing end point. This is due to the fact that both laser beams have an irregular interference pattern during polishing, but a specific interference pattern is detected when the polishing end point is reached. It is determined that the polishing end point has been reached.

When the polishing end point is detected by using such a polishing end detecting device, it is necessary to irradiate the surface to be polished of the semiconductor wafer with a laser beam so that the reflected light can be detected. Here, in the conventional polishing apparatus as described above, the semiconductor wafer held by the chuck is pressed from above onto the polishing surface of the polishing pad member disposed upward, and the pad and the wafer are moved in the same direction or in the opposite direction. Since the wafer is polished by rotating in the direction, it is necessary to irradiate a laser beam to the surface to be polished on the lower surface side of the wafer from below. In order to be able to irradiate laser light from below, a polishing through-hole and a platen member holding the polishing pad are formed with measurement through-holes vertically penetrating therethrough. It has been considered to detect reflected laser light.

[0005]

However, as described above, when polishing the surface of a semiconductor wafer, the semiconductor wafer is pressed from above while supplying an abrasive (slurry) onto the polishing surface of the polishing pad member. Since the wafer is polished by rotating the pad and the wafer in the same direction or in the opposite direction, there is a problem that the liquid abrasive (slurry) flows out through the through hole for measurement. In order to prevent such outflow of the abrasive (slurry),
It is conceivable to insert and arrange a member that transmits laser light such as a glass plate in the through hole for measurement. However, when the through hole for measurement is closed in this way, the through hole for measurement on the upper surface side from the glass plate is considered. There is a problem that an abrasive (slurry) accumulates in the holes. In particular, since the abrasive (slurry) is a liquid that is difficult to pass through the cloudy laser light, there is a problem that if the abrasive (slurry) accumulates in the through hole for measurement, it becomes difficult to detect the end point by the laser light. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides a polishing apparatus having a configuration capable of reliably and easily detecting an optical polishing end point without causing a problem of slurry outflow. The purpose is to provide. Another object of the present invention is to provide a method for manufacturing a semiconductor device using such a polishing apparatus and a semiconductor device manufactured by this method.

[0007]

In order to achieve the above object, a polishing apparatus according to the present invention comprises: an object holding device for holding an object to be polished with a surface to be polished facing upward; A polishing pad member having a polishing surface for polishing, and a pad holding device disposed above the object holding device and holding the polishing pad member with the polishing surface facing downward,
The polishing surface of the polishing pad member is configured to be relatively moved while being brought into contact with the surface to be polished from above, thereby polishing the surface to be polished. The pad holding device is provided with an optical measuring device that optically measures the state of the surface to be polished of the object to be polished from above through an opening formed in the polishing pad member.

In the polishing apparatus having such a configuration, the object to be polished (for example, a semiconductor wafer) is held by the object holding device with its surface to be polished facing upward. And irradiates the surface to be polished with side resistance from above. Therefore, even if a through hole for measurement is formed in the polishing pad member or the like, there is no possibility that the abrasive (slurry) flows out of the through hole for measurement.

In this polishing apparatus, the pad holding device includes a platen member for holding the polishing pad member with the polishing surface facing downward, and a rotation drive mechanism for rotating the platen member, and the opening portion is provided. However, it can be formed from a through opening formed by vertically penetrating the platen member and the polishing pad member while holding the polishing pad member. With this configuration, the surface to be polished of the object to be polished is irradiated with laser light or the like from above through the through-opening from above, and the reflected light is detected, thereby reliably and easily detecting the polishing end point. be able to. in this case,
Since the through-opening is formed to extend above the polishing pad surface, there is no possibility that the liquid slurry supplied to the polishing pad surface will flow out through this through-opening.

The through-opening can be constituted by a plurality of through-holes formed in the platen member and the polishing pad member, or may be constituted by a through-groove formed in the platen member and the polishing pad member. .

The pad holding device may further comprise a platen member for holding the polishing pad member with the polishing surface facing downward,
A rotation drive mechanism for rotating the platen member, wherein the platen member is made of a substantially transparent material that transmits measurement light from the optical measurement device, and the optical measurement device is configured to have openings of the platen member and the polishing pad member. The measurement of the surface to be polished may be performed by passing through. With this configuration, it is possible to irradiate the measuring light to the surface to be polished of the object to be polished and to detect the reflected light thereof through the substantially transparent platen member and the opening of the polishing pad member, and to reliably detect the polishing end point. Easy to do. Further, in this configuration, the through hole is unnecessary, and the problem that the abrasive (slurry) flows out does not occur.

When the platen member is made of a substantially transparent material as described above, a concave portion facing the opening of the polishing pad member is formed on the lower surface of the platen member, and the optical measuring device has a concave portion formed on the platen member. The measurement of the surface to be polished may be performed through the cut portion and the opening of the polishing pad member. In this case, the measurement hole from the optical measurement device is irradiated through the thinned portion of the platen member where the concave portion is formed, and the transmission loss of the measurement light is reduced, so that the polishing with higher precision can be completed. Point detection becomes possible.

Further, when the recess is formed as described above,
It is configured such that a substantially transparent gas is fed into the recess at a predetermined pressure, or a liquid having a property that is substantially transparent and does not affect the polishing of the surface to be polished by the polishing pad member is fed into the recess. Is preferred. As a result, it is possible to reliably prevent the liquid slurry from accumulating in the concave portion, suppress the transmission loss of the measurement light by the slurry, and detect the polishing end point with high accuracy.

Also in this case, the concave portion may be constituted by a plurality of cylindrical concave portions formed on the platen member and the polishing pad member, or may be constituted by groove-shaped concave portions formed on the platen member and the polishing pad member. I can do it.

A pad holding device according to the present invention comprises a platen member for holding a polishing pad member with a polishing surface facing downward, and a rotation drive mechanism for rotating the platen member. Consisting of a through-opening formed by vertically penetrating the platen member and the polishing pad member while holding the polishing pad member, and including a substantially transparent material through which the measuring light from the optical measuring device is transmitted. The optical member may be configured to measure the surface to be polished through the plug member after the inserted plug member is inserted.

In this polishing apparatus, it is not necessary to use a transparent material for the platen member, so that the degree of freedom in selecting the material of the platen member is high. In addition, since the measurement light is emitted through a plug member made of a transparent material, the surface to be polished can be reliably and easily measured. Furthermore, since the through-opening is closed by the plug member, there is no problem that the slurry penetrates into the through-opening and hinders the transmission of the measurement light.

At this time, the plug member may be slidably arranged vertically in the through-opening and an urging means for urging the plug member downward may be provided. As a result, the lower end surface of the plug member is pressed against the surface to be polished, and the slurry between the lower end surface of the plug member and the surface to be polished is removed. The polishing end point can be detected with high accuracy.

An object to be polished by the polishing apparatus configured as described above is a semiconductor wafer, and the method of manufacturing a semiconductor device according to the present invention uses the polishing apparatus according to the present invention as described above. And a step of flattening the surface.

The semiconductor device according to the present invention is manufactured by the semiconductor device manufacturing method according to the present invention.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a polishing apparatus according to the present invention. The polishing apparatus includes a body 11 rotatably supported by a rotary drive shaft 12.
A wafer holding device 10 having a chuck 13 for holding a wafer W by vacuum suction therein is provided. In the wafer holding device 10, the wafer W is suction-held on the upper surface of the chuck 13 with the surface to be polished WUS as the upper surface, and the rotary drive shaft 12 is driven to rotate, so that the wafer W is also driven to rotate. The rotary drive shaft 12 is further configured so that the entirety thereof is swingably moved in a horizontal direction by a swing mechanism (not shown).

A pad holding device 20 is provided above the wafer holding device 10 so as to face the wafer holding device 10. The pad holding device 20 includes a disk-shaped platen 21 made of a transparent material (transparent glass, transparent resin, or the like). The lower surface of the platen 21 is formed as a flat surface, and a polishing pad 25 is attached thereto. A cylindrical rotary member 33 is attached to the upper surface of the platen 21 by bolts. A pulley 34 is fixedly mounted on the outer periphery of the cylindrical rotary member 33, and the cylindrical rotary member 3 is
3 is driven to rotate, and the platen 21 is also driven to rotate. For this reason, the cylindrical rotating member 33
Is a cylindrical fixing member 31 fixed to the apparatus frame 30.
Are rotatably held by bearings 32.

At the center of the upper surface of the platen 21, a pair of left and right cooling water supply pipes 36a and 36b and a slurry supply pipe 37 are attached. These cooling water supply pipes 36a, 3
A rotary joint 38 is provided at the upper end of the slurry supply pipe 6b and the slurry supply pipe 37. Supply and discharge of the cooling water and supply of the slurry from the fixed head 39 to these supply pipes 36a, 36b, and 37 rotating together with the platen 21 are performed. . The cooling water supplied from the cooling water supply pipe 36a flows through the cooling water passage 22 formed in the platen 21, returns through the cooling water supply pipe 36b, and is discharged. On the other hand, the liquid slurry S supplied through the slurry supply pipe 37 passes through the slurry supply holes 23 formed vertically through the platen 21 and faces the polishing pad 25 at the lower end of the slurry supply holes 23. The slurry W is supplied between the polishing pad 25 and the surface WUS to be polished of the wafer W through the slurry supply opening 26 formed as described above.

When polishing the surface WUS to be polished of the wafer W, first, the wafer W is suction-held on the upper surface of the chuck 13 of the wafer holding device 10 with the surface WUS to be polished facing upward. On the other hand, the platen 21 constituting the pad holding device 20 is moved down, and the polishing pad 25 attached to the lower surface of the platen 21 is brought into contact with the polishing surface WUS of the wafer W held by the wafer holding device 10. And, the cooling water supply pipe 36a,
Cooling water flows into the cooling water passage 22 from 36b, and the supply of slurry is started from the slurry supply pipe 37 to the polishing pad 25 and the polishing surface WUS of the wafer W through the slurry supply hole 23 and the slurry supply opening 26. I do.

In this state, the rotary drive shaft 12 of the wafer holding device 10 is rotated to rotate the wafer W and swing horizontally, and at the same time, rotate the platen 21 in the same direction as the wafer W or in the opposite direction. . Thus, the polished surface WUS of the wafer W is polished by the polishing action of the slurry.

When polishing such a wafer W,
An optical measuring device 40 for detecting a polishing end point is attached to the frame 30 via a bracket 41. The optical measuring device 40 irradiates the surface of the wafer with measuring light and detects the polishing end point based on interference of the reflected light, etc., and is generally known in the art. Is omitted. The light (laser light or the like) emitted from the optical measurement device 40 and the reflected light are exemplarily shown by broken lines in FIG. 1, and a plurality of measurement lights from the optical measurement device 40 are transmitted through the platen 21. The polished surface WUS of the wafer W is irradiated, and the reflected light is transmitted through the platen 21 and received by the optical measurement device 40.

FIG. 2 is an enlarged view of the components of the measurement by the optical measuring device 40. In this figure, one measuring light is shown as an example. As can be clearly understood from this figure, a measurement opening 27 is formed in a portion of the polishing pad 25 affixed to the lower surface of the platen 21 where measurement light from the optical measurement device 40 is irradiated. Therefore, the measurement light emitted from the optical measurement device 40 passes through the transparent platen 21 and irradiates the polished surface WUS of the wafer W through the measurement opening 27 as shown by the broken line in the figure. The polishing pad 25 and the surface W to be polished
Although the slurry S is supplied between the substrate and the US to form a thin layer, the layer is an extremely thin layer and hardly affects the transmission of the measurement light. Thus, the surface to be polished W
The measurement light irradiated to the US and reflected from the US is received by the optical measurement device 40 through the measurement opening 27 and the platen 21 in the opposite manner to the above, and the polishing end point is detected. In this example, the entire platen 21 is made of transparent glass, resin, or the like, but a portion that transmits the measurement light may be configured to be transparent.

The polishing end point is detected optically by the optical measuring device 40 as described above. The configuration for optically detecting the polishing end point in the polishing apparatus according to the present invention is as described above. However, the present invention is not limited to this and includes various configurations described below. In the following description, the same functional parts or portions as those shown in FIGS. 1 and 2 are denoted by the same reference numerals for ease of description.

First, there is a configuration shown in FIG. 3 as a second embodiment. In this configuration, the measurement through-hole 51 penetrating vertically through the platen 21 is formed and the through-hole 51 is formed.
A measurement opening 27 is formed in the polishing pad 25 so as to face the surface of the polishing pad 25. The through hole 51 and the measurement opening 27 form a path through which measurement light from the optical measurement device 40 is irradiated. In this configuration, it is not necessary to make the platen 21 from a transparent material, and the degree of freedom in material selection is large. Further, the light transmission loss of the measurement light is smaller than in the case where the light is transmitted through a transparent material as shown in FIG. 1, and more accurate measurement is possible. In addition,
Although the slurry S enters the measurement through-hole 51, since the through-hole 51 is opened upward, there is no possibility that the slurry flows out from the through-hole unlike a conventional polishing apparatus.

FIG. 4 shows a third embodiment. The platen 21 used here is made of transparent glass, resin, or the like, and has a cylindrical measurement concave portion 52 opened downward at a portion irradiated with the measurement light from the optical measurement device 40, A lid 53 is left on the upper part. A measurement opening 27 is formed in the polishing pad 25 so as to face the measurement concave portion 52. In the case of this configuration, the measurement light from the optical measurement device 40 needs to pass through the lid 53, so that a slight light transmission loss occurs in this portion.
In this case, the transmission loss is smaller than that of the case (1), and highly accurate measurement is possible. Further, when the through-hole 51 is formed as shown in FIG. 3, there is a possibility that the slurry S is scattered and a splash-like slurry comes out upward.
2, there is no possibility that the slurried slurry S jumps out. Although the platen 21 may be entirely made of a transparent material, the cover 5
Only 3 may be configured to be transparent.

FIG. 5 shows a fourth embodiment, in which a platen 21 according to the embodiment shown in FIG. 4 is provided with a branch passage 54 connected to the inside of the measurement concave portion 52. An external pipe 55 is connected to 54. External piping 5
5 is supplied with nitrogen gas, clean air or the like, and the inside of the measurement concave portion 52 is pressurized by this gas. This allows
It is possible to suppress the slurry S from entering the concave portion 52 for measurement, reduce the obstruction of the measurement light passing through the concave portion 52 for measurement by the slurry S, and improve the measurement accuracy.

The gas supplied into the measuring recess 52 is not limited to nitrogen gas and clean air, but is inert to the slurry S and does not cause transmission loss of the measuring light. Gas can be used. Further, a liquid such as pure water that does not affect the polishing performance of the slurry S and does not cause a transmission loss of the measurement light may be supplied from the external pipe 55.

FIG. 6 shows a fifth embodiment in which a through hole 51 penetrating vertically through the platen 21 is formed, and a plug member 60 made of a transparent material slides up and down in the through hole 51. It is movably inserted. The polishing pad 2
5, a measurement opening 27 is formed facing the through hole 51. In this configuration, the stopper member 60 is pushed downward by its own weight, and its lower end surface 61 is almost in contact with the surface to be polished WUS of the wafer W. For this reason, the thickness of the slurry S layer between the lower end surface 61 of the plug member 60 and the surface to be polished WUS becomes extremely thin, and the transparent plug member 60 irradiated from the optical measurement device 40 is irradiated with the slurry S.
The measurement light transmitted through the inside is irradiated onto the polished surface WUS with almost no light transmission loss due to the slurry S.

In this configuration, since the through-hole 51 is closed by the plug member 60, the slurry S does not enter the through-hole 51. Further, the measuring light is transmitted through the plug member 60, and the platen 21 does not need to be transparent, so that the degree of freedom in selecting the material is high. However, since the lower end surface 61 of the plug member 60 is in contact with the surface to be polished WUS of the wafer W, the plug member 60 must be made of a material that does not adversely affect the film formed on the surface to be polished WUS of the wafer W. is there. In addition, the lower end surface of the plug member 60 is also polished by polishing, and its length is shortened. However, since the vertical stroke SP of the plug member 60 is set to be sufficiently large, the lower end surface 61 of the plug member 60 always comes into contact with the polishing surface WUS of the wafer W. In addition, when the plug member 60 is worn out by polishing for a long time, it can be easily replaced with a new plug member 60.

As shown in FIG. 7, the plug member 60 may be urged downward by a compression spring 64 supported by a bracket 63 provided on the upper surface of the platen 21. By doing so, the lower end surface 61 of the plug member 60
Is always in contact with the surface to be polished WUS of the wafer W, so that the transmission loss of the measuring light by the slurry S can be minimized.

By the way, in the polishing apparatus described above, the through-hole 51 or the cylindrical measuring concave portion 52 formed in the platen 21 is formed at a plurality of positions as shown in FIG. Thereby, the measurement at a plurality of positions is performed by the optical measurement device 40 during the polishing of the wafer W, and the accurate polishing end point is detected. In addition, as shown in FIG.
A through hole 51 or a cylindrical measurement concave portion 52 may be formed at two places.

Further, as shown in FIGS. 10 and 11, a groove-shaped through-opening (through-groove) 5 is used instead of the through-hole 51.
1 'may be formed, or a groove-shaped measurement concave portion 52' may be formed in place of the cylindrical measurement concave portion 52.

Next, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described. FIG. 12 is a flowchart showing a semiconductor device manufacturing process. When the semiconductor manufacturing process is started, first, in step S200
Then, an appropriate processing step is selected from the following steps S201 to S204, and the process proceeds to any one of the steps.

Here, step S201 is an oxidation step of oxidizing the surface of the wafer. Step S202 is CV
C to form insulating film and dielectric film on wafer surface by D
This is a VD process. Step S203 is an electrode forming step of forming electrodes on the wafer by vapor deposition or the like. Step S2
Reference numeral 04 denotes an ion implantation step of implanting ions into the wafer.

After the CVD step (S202) or the electrode forming step (S203), the process proceeds to step S205. Step S205 is a CMP process. In the CMP process, the polishing apparatus according to the present invention performs processes such as planarization of an interlayer insulating film, polishing of a metal film on a semiconductor device surface, polishing of a dielectric film, and single damascene and dual damascene. .

The CMP step (S205) or the oxidation step
After (S201), the process proceeds to step S206. Step S
206 is a photolithography step. In this step, a resist is applied to the wafer, a circuit pattern is printed on the wafer by exposure using an exposure device, and the exposed wafer is developed. Further, in the next step S207, portions other than the developed resist image are removed by etching.
Thereafter, the resist is removed, and this is an etching step of removing unnecessary resist after etching.

Next, it is determined in step S208 whether all necessary steps have been completed. If not, step S2
Returning to step 00, the previous steps are repeated to form a circuit pattern on the wafer. If it is determined in step S208 that all steps have been completed, the process ends.

In the semiconductor device manufacturing method according to the present invention, since the polishing apparatus according to the present invention is used in the CMP process, the throughput of the CMP process is improved. As a result, there is an effect that a semiconductor device can be manufactured at a lower cost than a conventional semiconductor device manufacturing method. The polishing apparatus according to the present invention may be used in a CMP step of a semiconductor device manufacturing process other than the above-described semiconductor device manufacturing process. Further, the semiconductor device manufactured by the semiconductor device manufacturing method according to the present invention is manufactured at a high throughput, so that it is a low-cost semiconductor device.

[0043]

As described above, the polishing apparatus according to the present invention is configured such that the polishing surface of the polishing pad member is relatively moved while being brought into contact with the surface to be polished from above to polish the surface to be polished. The pad holding device is provided with an optical measuring device for optically measuring the state of the surface to be polished of the object to be polished from above through an opening formed in the polishing pad member. In the polishing apparatus having such a configuration, the object to be polished (for example, a semiconductor wafer) is held by the object holding device with its surface to be polished facing upward. It is arranged in the holding device and configured to irradiate the surface to be polished with measurement light from above. Therefore, even if a through hole for measurement is formed in the polishing pad member or the like, there is no possibility that the abrasive (slurry) flows out of the through hole for measurement.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration according to a first embodiment of a polishing apparatus according to the present invention.

FIG. 2 is a cross-sectional view showing, in an enlarged manner, a measurement component of an optical measuring device in the polishing apparatus.

FIG. 3 is an enlarged cross-sectional view illustrating a measurement component of an optical measurement device in a polishing apparatus according to a second embodiment.

FIG. 4 is a cross-sectional view showing, in an enlarged manner, a measurement component by an optical measurement device in a polishing apparatus according to a third embodiment.

FIG. 5 is an enlarged cross-sectional view showing a measurement component by an optical measurement device in a polishing apparatus according to a fourth embodiment.

FIG. 6 is an enlarged cross-sectional view showing a measurement component by an optical measurement device in a polishing apparatus according to a fifth embodiment.

FIG. 7 is a cross-sectional view showing, on an enlarged scale, a modified example of a measurement component by an optical measurement device in the polishing apparatus according to the fifth embodiment.

FIG. 8 is a bottom view showing the shape of a measurement through hole or a measurement recess formed in a platen in the polishing apparatus according to the present invention.

FIG. 9 is a bottom view showing an example in which the shape of a measurement through-hole or a measurement recess formed in a platen in the polishing apparatus according to the present invention is different.

FIG. 10 is a bottom view showing an example in which a shape of a measurement through hole or a measurement recess formed in a platen in the polishing apparatus according to the present invention is different.

FIG. 11 is a bottom view showing an example in which the shape of a measurement through-hole or a measurement recess formed in a platen in the polishing apparatus according to the present invention is different.

FIG. 12 is a flowchart showing a manufacturing process of a semiconductor device according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 Wafer holding device 13 Chuck 20 Pad holding device 21 Platen 25 Polishing pad 40 Optical measuring device 51 Measurement through hole 52 Measurement concave portion 53 Cover portion 60 Plug member S Slurry W Wafer

Claims (14)

[Claims] An object holding device for holding an object to be polished with a surface to be polished facing upward; a polishing pad member having a polishing surface for polishing the surface to be polished; A pad holding device that is disposed above and holds the polishing pad member with the polishing surface facing downward, while the polishing surface of the polishing pad member contacts the surface to be polished from above. A polishing apparatus configured to polish the surface to be polished by relatively moving, the state of the surface to be polished of the object to be polished from above through an opening formed in the polishing pad member through the pad holding device. A polishing apparatus, comprising: an optical measuring device for optically measuring the temperature. 2. The pad holding device has a platen member that holds the polishing pad member with the polishing surface facing downward, and a rotation drive mechanism that rotates the platen member. The polishing apparatus according to claim 1, further comprising a through-opening formed by vertically penetrating the platen member and the polishing pad member while holding the polishing pad member. 3. The polishing apparatus according to claim 2, wherein said through-opening comprises a plurality of through-holes formed in said platen member and said polishing pad member. 4. The polishing apparatus according to claim 2, wherein said through-opening comprises a through-groove formed in said platen member and said polishing pad member. 5. The pad holding device has a platen member for holding the polishing pad member with the polishing surface facing downward, and a rotation drive mechanism for rotating the platen member, wherein the platen member is the optical device. The optical measurement device is configured to measure the surface to be polished through the opening of the platen member and the polishing pad member, the measurement device being made of a substantially transparent material that transmits measurement light from the measurement device. 2. The polishing apparatus according to 1. 6. A concave portion facing the opening of the polishing pad member is formed on a lower surface of the platen member, and the optical measuring device is configured such that the portion of the platen member where the concave portion is formed and the polishing pad member The polishing apparatus according to claim 5, wherein the measurement of the polished surface is performed through an opening. 7. The apparatus according to claim 6, wherein a substantially transparent gas is fed into said recess at a predetermined pressure.
A polishing apparatus according to claim 1. 8. The polishing apparatus according to claim 6, wherein a liquid having a property that is substantially transparent and does not affect the polishing of said polishing target surface by said polishing pad member is sent into said concave portion. apparatus. 9. The polishing apparatus according to claim 6, wherein said recess comprises a plurality of cylindrical recesses formed in said platen member and said polishing pad member. 10. The polishing apparatus according to claim 6, wherein said recess comprises a groove-like recess formed in said platen member and said polishing pad member. 11. The pad holding device includes: a platen member that holds the polishing pad member with the polishing surface facing downward; and a rotation drive mechanism that rotates the platen member. A through-opening is formed by vertically penetrating the platen member and the polishing pad member while holding the polishing pad member, and is substantially transparent for transmitting measurement light from the optical measuring device into the through-opening. The polishing apparatus according to claim 1, wherein a plug member made of a material is inserted, and the optical measurement device measures the polished surface through the plug member. 12. The apparatus according to claim 11, wherein said plug member is slidably disposed vertically in said through opening, and biasing means for biasing said plug member downward is provided. The polishing apparatus according to the above. 13. The polishing object is a semiconductor wafer, comprising a step of flattening the surface of the semiconductor wafer by using the polishing apparatus according to claim 1. Description: Semiconductor device manufacturing method. 14. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 13.