JP2001198802A - Polishing body, flattening device, manufacturing method for semiconductor device and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing body capable of dressing, by solving a problem that in-situ-measuring can not be done since a polishing body (polishing pad) is shaved and the surface of a window on the object side to be polished is injured and becomes optically opaque at the same time when dressing, in the case of a conventional polishing body. SOLUTION: This polishing body has one or more opening parts and windows installed at the opening parts. The surface of the window on the object side to be polished is recessed and the recessed quantity is gradually or continuously changing. Thereby, a polishing condition can be excellently in-situ-measured by switching to a window or a part of the window having no injury when a whole or a part of the surface of the window on the object side to be polished is injured by dressing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device such as ULSI, and more particularly to a polishing body and a flattening apparatus suitable for use in flattening and polishing a semiconductor device.
The present invention relates to a semiconductor device manufacturing method and a semiconductor device.

[0002]

2. Description of the Related Art As the degree of integration and miniaturization of a semiconductor integrated circuit increases, the steps of a semiconductor manufacturing process are increasing and becoming more complicated. Along with this, the surface of the semiconductor device is not necessarily flat. The presence of a step on the surface of a semiconductor device causes disconnection of wiring, an increase in local resistance, and the like, resulting in disconnection and a decrease in electric capacity.
In addition, in the case of an insulating film, withstand voltage degradation and leakage may occur.

On the other hand, as semiconductor integrated circuits become more highly integrated and miniaturized, the light source wavelength of a semiconductor exposure apparatus used for optical lithography becomes shorter, and the numerical aperture of a projection lens of the semiconductor exposure apparatus, the so-called NA, becomes larger. It has become to. As a result, the depth of focus of the projection lens of the semiconductor exposure apparatus has been substantially reduced. In order to cope with a shallower depth of focus, the surface of a semiconductor device needs to be flatter than ever.

Specifically, in a semiconductor process, a flattening technique as shown in FIGS. 11A and 11B has become essential. On a silicon wafer 121, a semiconductor device 124, an interlayer insulating film 122 made of SiO ₂ , and a metal film 123 made of Al are formed. FIG. 11A shows an example in which the interlayer insulating film 122 on the surface of the semiconductor device is flattened. FIG. 11B shows a metal film 123 on the surface of the semiconductor device.
Is polished to form a so-called damascene. As a method for planarizing such a semiconductor device surface, a chemical mechanical polishing (Chemical Mechanica) method is used.
l Polishing or Chemical Mechanical Planarization,
In the following, the technology is referred to as CMP). Currently C
MP technology is the only method that can planarize the entire surface of a silicon wafer.

[0005] CMP has been developed based on a mirror polishing method for silicon wafers. FIG. 12 is a schematic configuration diagram of a conventional flattening apparatus used for CMP. The flattening device includes a polishing member 131, a polishing object holding section (hereinafter, referred to as a polishing head) 132, and an abrasive supply section 134. Then, a silicon wafer 133 to be polished is attached to the polishing head 132, and an abrasive supply unit 134 supplies an abrasive (slurry) 135. The polishing member 131 is obtained by pasting a polishing body 137 on a surface plate 136.

The silicon wafer 133 is held by the polishing head 132, swings while rotating, and is pressed against the polishing body 137 of the polishing member 131 at a predetermined pressure. The polishing member 131 is also rotated to cause relative movement with the silicon wafer 133. In this state, the abrasive 135 is supplied from the abrasive supply unit 134 onto the polishing body 137, and the abrasive 135 is diffused on the polishing body 137, and the polishing body 137 is moved with the relative movement of the polishing member 131 and the silicon wafer 133. And between the silicon wafer 133 and the polishing surface of the silicon wafer 133. That is, the polishing member 1
The mechanical polishing by the relative movement of the silicon wafer 133 and the silicon wafer 133 and the chemical action of the polishing agent 135 act synergistically to perform good polishing.

The relationship between the polishing amount of the silicon wafer and the above polishing conditions is given by an empirical formula called Preston formula shown in (Formula 1).

R = k × P × V (Equation 1) where R is the polishing amount of the silicon wafer, P is the pressure per unit area for pressing the silicon wafer against the polishing body, and V is the relative motion between the polishing member and the silicon wafer. By relative linear velocity,
k is a proportionality constant.

[0009] In the CMP, the polishing rate varies depending on the temperature distribution of the polishing body and the location difference of the supply state of the polishing agent. In addition, since a change in the surface state of the polishing body causes a reduction in the polishing rate due to the number of processed pieces, a difference in the polishing rate due to individual differences in the polishing body, and the like, it is difficult to determine the end point by performing a predetermined polishing amount by time management. .

For this reason, a method has been proposed in which the end point is determined while in-situ measurement of motor torque, vibration, and the like is performed instead of the end point determination by time management.
These methods use CMP in which the material to be polished changes.
(Eg, CMP of a wiring material, CMP with a stopper layer) is effective to some extent. However, in the case of a silicon wafer having a complicated pattern, it may be difficult to determine the end point because the change in the material to be polished is small. In addition, in the case of CMP of an interlayer insulating film, it is necessary to control the capacitance between wirings, and therefore, it is required to manage not the polishing end point but the remaining film thickness. It is difficult to measure the film thickness by measuring the motor torque, vibration, and the like in-situ (in-situ measurement) and determining the end point.

In order to solve the above problems, recently, in-situ end point detection or in-situ
Tu film thickness measurement is considered to be effective. In the in-situ measurement configuration, as shown in FIG. 12, an opening 138 for measurement is provided on the surface plate 136 and the polishing body 137, and the surface of the object to be polished is measured by a device 139 that measures a polishing state through the opening 138. The method of observation is common. Although not shown in FIG. 12, a transparent window is generally provided on the polishing body 137 or the like to close the opening. By providing the window, the measurement light from the polishing state measuring device 139 passes through the window, but it is possible to prevent the abrasive 135 from leaking from the opening 138 to the polishing state measuring device 139.

During polishing, since the abrasive is discharged onto the abrasive body, the observation is made through the abrasive. Since the abrasive, which is a scatterer, attenuates the measurement light, it is preferable that the amount of the abrasive intervening in the measurement optical path be small when performing high-precision measurement. That is, if there is a step between the surface of the polishing body and the surface of the window on the side of the object to be polished, the polishing agent accumulates in the window and attenuates the measurement light.

A so-called polishing pad made of foamed polyurethane has been used as a polishing body. However, the polishing pad of the foamed polyurethane is clogged with the abrasive, and the polishing characteristics become unstable. For this reason, in the case of a polishing pad made of foamed polyurethane, dressing of the surface of the polishing pad made of foamed polyurethane is generally performed with a diamond grindstone in order to perform stable polishing. Dressing is a process of removing clogged abrasives and simultaneously shaving off the surface of the foamed polyurethane polishing pad to create a fresh polishing pad surface.

[0014]

However, at the same time as the polishing body (polishing pad) is shaved off during dressing, the window is damaged and becomes optically opaque, so that in-situ measurement cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a polishing body having a dressable window and a flattening apparatus when a polishing end point is detected and a film thickness is measured in-situ in a CMP process. The purpose is to get.

[0016]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that in the case of in-situ measurement, scattering of light by an abrasive, that is, that the distance between the window and the silicon wafer can be tolerated to some extent, and that the distance is allowed. The present inventors have found that even if dressing of the polished body does not cause any damage to the window, the present invention has been accomplished.

That is, in order to solve the above-mentioned problems, a polishing body according to the present invention is provided such that the polishing body is interposed between a polishing body placed on a surface plate and an object to be polished. A polishing body used for a flattening device that polishes the polishing object by applying a load between the object and the polishing object, and by relatively moving the polishing object, one or more openings, Wherein the surface of the window on the side of the object to be polished is concave with respect to the surface of the polishing body, and the amount of the concave changes stepwise or continuously. .

According to the above-mentioned polishing body, when the polished state of the object to be polished is observed by an apparatus for measuring the polished state by optically observing the polished surface of the object to be polished through a window, the surface of the object is not damaged. Use a window that is not marked or that is not scratched. Then, when the window or that portion of the window is damaged by dressing or polishing, an observation of the polishing state of the object to be polished by a device for measuring the polishing state is performed with no difference in the amount of dent in the initial state and no damage. By switching to windows or window parts,
In-situ measurement of the polished state can be performed, and the frequency of replacement of the polished body or window can be reduced. Thereby, the cost required for polishing can be reduced.

Further, it is preferable that the amount of the dent changes stepwise due to the fact that the amount of the dent differs for each of the openings (claim 2). Thus, when observing the polished state of the object to be polished by the apparatus for measuring the polished state, using a window whose surface is not scratched in the opening, when the window is scratched by dressing or polishing It is possible to perform in-situ measurement of the polished state by switching the observation of the polished state of the object to be polished by the apparatus for measuring the polished state to a window having an opening with a different amount of dent in the initial state and no damage. it can.

Further, it is preferable that the amount of the dent varies stepwise due to the difference in the amount of the dent in two or more portions within the same opening. Thereby, when observing the polished state of the object to be polished by the apparatus for measuring the polished state, using a portion of the window without scratches,
When the window is damaged by dressing or polishing, the observation of the polishing state of the object to be polished by the device for measuring the polishing state is switched to a window part with a different dent amount in the initial state and no damage. Thus, in-situ measurement of the polished state can be performed.

Further, it is preferable that the window is a transparent plate of a parallel plate shape, and the amount of the recess is continuously changed by the window being installed obliquely with respect to the surface of the polishing body. (Claim 4). Thereby, when observing the polished state of the object to be polished by the apparatus for measuring the polished state, when the undamaged portion of the window is used, when the portion of the window is damaged by dressing or polishing, By switching the observation of the polished state of the object to be polished by a device for measuring the polished state to a window portion having a different amount of dent in the initial state and having no scratch, the in-sit of the polished state
u Measurement can be performed.

Further, the window is a parallel plate-shaped transparent plate formed by laminating two or more transparent materials, and the transparent materials are laminated with an adhesive force enough to be peelable. It is preferable that the amount of the dent is changed stepwise by peeling off one by one (claim 5). This allows
When observing the polishing state of the object to be polished, using a window with no scratch on the surface, when the window is scratched by dressing or polishing, by peeling the transparent material on the top surface of the window, It is possible to switch to a window without scratches, and in-situ measurement of the polished state can be performed.

Further, the minimum dent amount dm of the dent amounts
It is preferable that in is 0 μm <dmin ≦ 400 μm (claim 6). As a result, the window does not come into contact with the object to be polished, so that the window is not damaged.

The maximum dent amount dm of the dent amounts is
ax is 0 μm <dmax ≦ 90% of the thickness of the polishing body, and the minimum thickness tmin of the windows is tmin ≧ 10% of the thickness of the polishing body, (Claim 7). Thus, the window does not come into contact with the object to be polished, so that the object to be polished and the window are not damaged. Further, since the thickness of the window is not too thin, the window is not deformed, and the detection of the polishing end point and the measurement of the film thickness are not unstable due to the deformation of the window.

Preferably, the transmittance of at least a part of the window is at least 22%. As a result, the attenuation of light intensity for measuring the polishing state passing through the window is reduced, so that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness do not decrease.

Preferably, an antireflection film is formed on a surface of the window opposite to the object to be polished (claim 9). Thereby, the amount of reflection of light for measuring the polishing state passing through the window on the surface of the window is reduced, and the attenuation of light intensity for measuring the polishing state is reduced, so that the detection accuracy of the polishing end point and The measurement accuracy of the film thickness does not decrease.

Further, in order to solve the above-mentioned problem, in the flattening apparatus according to the first aspect of the present invention, an abrasive is interposed between a polishing body provided on a surface plate and an object to be polished. In a flattening apparatus that applies a load between the polishing body and the object to be polished in the state, and moves the object relatively, the one or more openings formed in the surface plate are polished. Part, one or more openings formed in the polishing body, and installed on the surface plate so as to close at least a part of the opening provided in the polishing body or the opening formed in the polishing body. Window, having a device for optically observing the polished surface of the object to be polished through the window to measure the polished state, the opening formed in the polished body and the platen The formed opening overlaps with the surface of the polishing body. Be recessed said surface of the object to be polished side of the window for the amount seen recess is changing stepwise or continuously (claim 10).

According to the flattening apparatus, the apparatus for measuring the polishing state by optically observing the polished surface of the object to be polished through the window is used to observe the polished state of the object to be polished. An object to be polished by an apparatus that measures the state of polishing when the window or that part of the window is damaged by dressing or polishing using a window or a part of the window that is not damaged. By switching the observation of the polished state to a window or window part with a different amount of dent in the initial state and no scratch, in-situ measurement of the polished state can be performed, and the frequency of replacement of the polished body or window can be reduced. Can be reduced. Thereby, the cost required for polishing can be reduced.

Further, it is preferable that the amount of the depression changes stepwise by changing the amount of the depression for each of the openings formed in the polishing body. Thus, when observing the polished state of the object to be polished by the apparatus for measuring the polished state, using a window whose surface is not scratched in the opening, when the window is scratched by dressing or polishing It is possible to perform in-situ measurement of the polished state by switching the observation of the polished state of the object to be polished by the apparatus for measuring the polished state to a window having an opening with a different amount of dent in the initial state and no damage. it can.

Further, it is preferable that the amount of the dent changes stepwise due to the difference in the amount of the dent in two or more portions in the same opening. This allows
When observing the polished state of the object to be polished with a device for measuring the polished state, use the undamaged part of the window, and when the part of the window is damaged by dressing or polishing, the polished state The in-situ measurement of the polished state can be performed by switching the observation of the polished state of the object to be polished by the apparatus for measuring the polished state to a window portion having a different amount of dent in the initial state and having no damage.

It is preferable that the window is a transparent plate having a parallel flat plate shape, and the window is installed obliquely with respect to the surface of the polishing body, so that the amount of the recess changes continuously. (Claim 13). Thereby, when observing the polished state of the object to be polished by the apparatus for measuring the polished state, when the undamaged portion of the window is used, when the portion of the window is damaged by dressing or polishing, By switching the observation of the polished state of the object to be polished by a device for measuring the polished state to a window portion having a different amount of dent in the initial state and having no scratch, the in-sit of the polished state
u Measurement can be performed.

Further, the window is a parallel plate-shaped transparent plate formed by laminating two or more transparent materials, and the transparent materials are laminated with an adhesive force enough to be peelable. It is preferable that the dent amount is changed stepwise by peeling off one by one (claim 14). Thereby, when observing the polished state of the object to be polished, use a window having no scratch on the surface, and when the window is scratched by dressing or polishing, the transparent material on the top surface of the window is peeled off. As a result, it is possible to switch to a window that is not damaged, and in-situ measurement of the polished state can be performed.

The dent amount d of a portion of the window through which light from the apparatus for measuring the polishing state passes is 0 μm.
It is preferable that m <d ≦ 400 μm. As a result, the window does not come into contact with the object to be polished, so that the window is not damaged.

The maximum dent amount dm of the dent amounts
ax is 0 μm <dmax ≦ 90% of the thickness of the polishing body, and the minimum thickness tmin of the window thickness is
It is preferable that tmin ≧ 10% of the thickness of the polishing body (claim 16). Thus, the window does not come into contact with the object to be polished, so that the object to be polished and the window are not damaged. Further, since the thickness of the window is not too thin, the window is not deformed, and the detection of the polishing end point and the measurement of the film thickness are not unstable due to the deformation of the window.

It is preferable that the window is made of a resin having polishing characteristics equivalent to those of the polishing body. Thus, even when the window comes into contact with the silicon wafer to be polished, the window does not scratch the polished surface of the silicon wafer or cause uneven polishing.

Further, in order to solve the above-mentioned problem, in the flattening apparatus according to the second aspect of the present invention, an abrasive is interposed between a polishing body provided on a surface plate and an object to be polished. In a flattening apparatus that applies a load between the polishing body and the object to be polished in the state, and moves the object relatively, the one or more openings formed in the surface plate are polished. Part, one or more openings formed in the polishing body, a window installed so as to cover at least a part of the opening formed in the polishing body, and the object to be polished through the window. An apparatus for optically observing the polished surface and measuring a polished state, and a moving device for moving the position of the surface of the window on the side of the object to be polished, wherein the opening formed in the polished body And the opening formed in the surface plate overlap with each other, Window is installed in the plate via the mobile device (claim 18).

According to the flattening apparatus, when the polishing state of the object to be polished is observed by an apparatus for measuring the state of polishing by optically observing the polished surface of the object to be polished through the window, By controlling the distance between the surface of the object to be polished and the surface of the object to be polished, the surface of the window on the object to be polished is not damaged by dressing or polishing, and in-situ measurement of the polished state is performed. The frequency of replacement of the abrasive body or window can be reduced. Thereby, the cost required for polishing can be reduced.

Further, an apparatus for detecting an interval between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished, an apparatus for detecting a wear state of the polished body, or an apparatus for detecting both of them. It is preferable to further have (claim 1)
9). This makes it possible to detect the distance between the surface of the window on the object to be polished and the polished surface of the object to be polished.

It is preferable that the apparatus further comprises a control device for controlling a distance between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished (claim 20). Thus, the distance between the surface of the window on the polishing object side and the polishing surface of the polishing object can be controlled by the control device.

The controller predicts the amount of wear of the polishing body from the polishing conditions, the polishing time, the dressing conditions and the dressing time, and polishes the surface of the window on the polishing object side and the polishing of the polishing object. It is preferable to control the distance from the surface (claim 21). Thus, the window is not damaged by polishing and dressing.

Preferably, the control device controls the moving device so that a distance between a surface of the window on the object to be polished and the surface of the object to be polished is constant. ). Thus, the window is not damaged by polishing and dressing.

Preferably, the control device controls an interval between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished in synchronization with rotation of the surface plate. ). Thus, the window is not damaged by polishing and dressing.

The distance d between the surface of the window on the object to be polished and the surface of the object to be polished is 0 μm ≦ d ≦ 400 μm
(Claim 24). Thus, the window is not damaged by polishing and dressing.

The distance d between the surface of the window on the object to be polished and the polished surface of the object to be polished is 0 μm ≦ d ≦ 90% of the thickness of the polished body, and The thickness of the window
It is preferable that t satisfies t ≧ 10% of the thickness of the polishing body (claim 25). Thus, the object to be polished or the window is not damaged by the polishing and the dressing. Further, since the thickness of the window is not too thin, the window is not deformed, and the detection of the polishing end point and the measurement of the film thickness are not unstable due to the deformation of the window.

The light emitted from the apparatus for measuring the polishing state passes through the window, passes through the polishing agent between the window and the object to be polished, and is reflected on the polishing surface of the object to be polished. Reflected, passes again through the abrasive between the window and the object to be polished, passes through the window again, returns to the apparatus for measuring the polishing state, and exits from the apparatus for measuring the polishing state. Preferably, the ratio of the light intensity returning to the device for measuring the polishing state to the light intensity is 5% or more (claim 26). As a result, the intensity of the light returning to the apparatus for measuring the polishing state becomes sufficient to measure the polishing state, so that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness by the apparatus for measuring the polishing state decrease. Disappears.

Preferably, an antireflection film is formed on a surface of the window opposite to the object to be polished (claim 27). As a result, the amount of light reflected on the surface of the window for measuring the polishing state passing through the window is reduced, and the attenuation of the light intensity for measuring the polishing state is reduced.
The detection accuracy of the polishing end point and the measurement accuracy of the film thickness do not decrease.

Further, a semiconductor device manufacturing method according to the present invention includes a step of flattening the surface of a semiconductor wafer using the flattening apparatus according to the present invention (claim 28).

According to the method of manufacturing a semiconductor device, since the flattening apparatus according to the present invention is used in the step of flattening the surface of the semiconductor wafer, the end point of polishing is detected in the step of flattening the surface of the semiconductor wafer. The yield in the step of flattening the surface of the semiconductor wafer is improved because the accuracy or the measurement accuracy of the film thickness does not decrease. As a result, a semiconductor device can be manufactured at a lower cost than a conventional semiconductor device manufacturing method.

Further, the semiconductor device according to the present invention comprises:
It is manufactured by the semiconductor device manufacturing method according to the present invention (claim 29).

According to the semiconductor device, since it is manufactured by the semiconductor device manufacturing method according to the present invention,
A semiconductor device can be manufactured at a lower cost than a conventional semiconductor device manufacturing method, and the manufacturing cost of the semiconductor device can be reduced.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A polishing body according to a first embodiment of the present invention and a flattening apparatus according to a second embodiment of the present invention will be described. 1 (a), (b), (c),
(D) is a diagram showing a polishing body according to the first embodiment of the present invention. 1 (a) is a top view, FIG. 1 (b) is a cross-sectional view of the A-O portion of FIG. 1 (a), and FIG. 1 (c) is a cross-sectional view of the B-O portion of FIG. 1 (a). FIG. 1D is a cross-sectional view of a portion C-O in FIG. 1A.

In the first embodiment, the polishing body 12 has three openings 13a, 13b, 13c. A window 11a is provided in the opening 13a, a window 11b is provided in the opening 13b, and a window 11c is provided in the opening 13c. FIG.
In (b), (c), and (d), the upper surface of the polishing body 12 in the figure is the surface of the polishing body, and the upper surfaces of the windows 11a, 11b, and 11c in the figures are the polishing object side of the windows. Surface.

The surfaces of the windows 11a, 11b, 11c are recessed with respect to the surface of the polishing body 12, and the amount of each recess differs for each opening. As a result, the amount of dent at each opening changes stepwise. In the polishing body 12 according to the first embodiment, the amount of depression of the surface of the polishing body on the side of the object to be polished with respect to the surface of the polishing body is the shortest in the window 11a of the opening 13a and the longest in the window 11c of the opening 13c. The amount of depression of the window 11b of the opening 13b is substantially the middle of the amount of depression of the opening 13a and the amount of depression of the opening 13c.

FIG. 2 is a schematic configuration diagram of a flattening apparatus according to a second embodiment of the present invention. The flattening device according to the present invention includes a polishing member 31, a polishing object holding portion 32 (hereinafter, referred to as a polishing head), and a polishing agent supply portion. A silicon wafer 33 to be polished is attached to the polishing head 32, and an abrasive supply section 34 supplies an abrasive (slurry) 35. The polishing member 31 is obtained by installing the polishing body 12 according to the above-described first embodiment on a surface plate 36 having an opening 38, and the polishing body 12 is attached to the surface plate 36 with a double-sided tape or an adhesive. It is attached. A device 39 for optically observing the polished surface of the silicon wafer 33 to be polished through the opening 38 and measuring the polished state is also provided. Although only one opening is shown in FIG. 2,
The platen 36 of the flattening device according to the second embodiment is a polishing body.
It has three openings corresponding to the number of twelve openings. In FIG. 2, the windows provided on the polishing body 12 are omitted. An opening 38 formed in the surface plate 36 and an opening (not shown) formed in the polishing body 12 overlap with each other. Although not shown, the other two openings of the surface plate 36 are also
The opening formed in 36 and the opening formed in polishing body 12 overlap. Thus, by providing a transparent window at the opening of the polishing body 12, the light 17 emitted from the polishing state measuring device 39 and the light reflected by the polished surface of the silicon wafer 33 pass through the window, Abrasive 35 is open
It can be prevented from leaking from 38 to below the platen 36.

The silicon wafer 33 to be polished is held by the polishing head 32, oscillated while rotating, and pressed against the polishing body 12 of the polishing member 31 with a predetermined pressure. The polishing member 31 is also rotated to cause relative movement with the silicon wafer 33. In this state, the abrasive 35 is supplied onto the abrasive body 12 from the abrasive supply section 34, and the abrasive 35
The silicon wafer 33 diffuses upward and enters between the polishing body 12 and the silicon wafer 33 with the relative movement of the polishing member 31 and the silicon wafer 33 to polish the polished surface of the silicon wafer 33. That is, the mechanical polishing by the relative movement between the polishing member 31 and the silicon wafer 33 and the chemical action of the polishing agent 35 act synergistically to perform good polishing.

Immediately after the start of polishing, in the initial state, the opening 13a where the amount of depression of the surface of the window on the polishing object side with respect to the surface of the polishing body is the shortest is used for observing the state of the polished surface. Thus, of the light emitted from the polishing state measuring device 39, reflected on the polished surface of the silicon wafer 33, and returned to the polishing state measuring device 39, the window 11a provided in the opening 13a is transmitted through the window 11a. The state of the polished surface is observed by the passing light.
On the surface plate 36, a position detection sensor (not shown) is installed. When the surface plate 36 rotates and a specific position of the surface plate 36 comes to the position of the position detection sensor, the position detection sensor outputs a trigger signal. A device that measures the polishing state from the position of the surface plate 36, where the surface plate 36 rotates and the position detection sensor outputs a trigger signal.
The time interval until the opening 13a reaches above 39 is
It is determined by the number of rotations of 6. The time interval may be calculated or measured in advance, and the device 39 for observing the state of the polished surface may be operated when the time interval elapses after the position detection sensor outputs the trigger signal. Thus, it is possible to always detect the polishing end point or measure the film thickness in the opening 13a.

Each time one silicon wafer is polished, dressing of the polished body is performed. For dressing, a diamond grindstone or the like is used. After dressing,
Next, a silicon wafer to be polished is attached to the polishing head 32, and polishing is performed. Thus, the polishing step and the dressing step are alternately repeated.

Each time the dressing is performed, the surface of the polishing body 12 is shaved, and the amount of depression of the window 11a of the opening 13a with respect to the surface of the polishing body 12 is reduced. The surface on the object side will be damaged. When the window is damaged, the scattering of light at the window increases, and the accuracy of detection of the polishing end point and the accuracy of the film thickness measurement decrease. For this reason, the detection of the polishing end point and the measurement of the film thickness in the initial state have the second smallest opening 13
Switch to b. In order to switch the detection of the polishing end point and the measurement of the film thickness to be performed at the opening 13b, the position detection sensor installed on the surface plate 36 outputs a trigger signal and then activates the polishing state measuring device 39. May be changed to an appropriate time interval, and the apparatus 39 for measuring the polishing state may be operated when the opening 13b comes over the apparatus 39 for measuring the polishing state.

Then, by repeating the polishing step and the dressing step, the amount of depression of the surface of the window 11b of the opening 13b on the side of the object to be polished becomes zero, and the surface of the window 11b on the side of the object to be polished is damaged by the dressing. Then, the detection is switched so that the detection of the polishing end point and the measurement of the film thickness are performed in the opening 13c having the longest recess in the window in the initial state. The detection of the polishing end point and the switching from the openings 13b to 13c for the film thickness measurement may be performed in the same manner as the switching from the openings 13a to 13b described above. As described above, during dressing, the surface on the side of the object to be polished of the window provided in the opening used for detecting the polishing end point and measuring the film thickness is concave with respect to the surface of the polishing body. The windows are not scratched.

When the amount of light received by the device 39 for measuring the polishing state becomes smaller than a predetermined value, a control device for switching to the next opening is provided to switch the opening. You may go.

In the first and second embodiments,
The platen 36 has three openings, and the polishing body 12 has three openings in which windows are provided. The number of these openings may be two or four. More than one. In that case, the observation of the polishing state can be switched the number of times corresponding to the number of these openings.

In the flattening apparatus according to the second embodiment, in which the polishing body according to the first embodiment is installed, a plurality of windows having different recesses for each opening are installed in the polishing body 12. Therefore, even if the window is damaged due to dressing and becomes optically opaque, the detection of the polishing end point and the measurement of the film thickness can be performed by switching the window used for detecting the polishing end point and measuring the film thickness to another opening. Will be possible. As a result, the same polishing body can be used for polishing for a long period of time as compared with the related art, and the frequency of replacement of the polishing body or the window is reduced, so that there is an effect that the cost for polishing can be reduced.

Next, a polishing body according to a third embodiment of the present invention and a flattening device according to a fourth embodiment of the present invention will be described. FIGS. 3A and 3B show a third embodiment of the present invention.
It is a figure showing a polish object by an embodiment. FIG. 3 (a)
FIG. 3B is a top view, and FIG. 3B is a cross-sectional view taken along the line D-E in FIG.

The polishing body 22 according to the third embodiment has one opening. Windows installed in the opening
The cross section 21 has a stepped shape, and the amount of depression of the surface of the window 21 on the polishing object side with respect to the surface of the polishing body is three.
a, 21b, 21c are different. The concave amount of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body is the shortest at the portion 21a, the longest at the portion 21c, and the portion 21b is the same as the portion 21a.
It is almost the middle length of the part of 1c. This allows
The amount of depression of the surface of the window 21 on the side of the object to be polished changes stepwise.

When a polymer resin is used as the material of the window 21, the window 21 having a step-shaped step on the surface is manufactured by pouring a resin in a dissolved state into a mold having a step and curing the resin.

The flattening device according to the fourth embodiment is the same as the flattening device according to the second embodiment (FIG. 2).
In place of the abrasive body (12 in FIG. 2) according to the third embodiment,
The polishing body 22 according to the embodiment is installed. However, since the polishing body 22 according to the third embodiment has only one opening, only one opening is formed in the surface plate 36 of the flattening apparatus according to the fourth embodiment. It is. The opening formed in the platen 36 is a polishing body.
It overlaps with the opening formed in 22. The description of the same parts as those of the flattening device according to the second embodiment will be omitted.

Immediately after the start of polishing, in the initial state, the amount of depression of the surface of the window 21 on the side of the object to be polished with respect to the surface of the polishing body is the shortest.
The portion 21a is used for observing the state of the polished surface. Accordingly, of the light emitted from the polishing state measuring device 39, reflected on the polished surface of the silicon wafer 33, and returned to the polishing state measuring device 39, the light passing through the portion 21a of the window 21 is used. The condition of the polished surface is observed. A position detection sensor (not shown) is provided on the surface plate 36 as in the flattening device according to the second embodiment. The platen 36 rotates and reaches the portion 21a of the window 21 installed in the opening above the polishing state measuring device 39 from the position of the platen 36 where the position detection sensor outputs a trigger signal. The time interval up to the platen 36
Is determined by the number of rotations. Therefore, similarly to the second embodiment, an apparatus for calculating or measuring the time interval in advance and observing the state of the polished surface after the time interval elapses after the position detection sensor outputs the trigger signal.
You only need to operate 39.

Then, similarly to the second embodiment, the polishing step and the dressing step are repeated.

Each time the dressing is performed, the surface of the polishing body 22 is shaved, and 21a of the window 21 of the opening with respect to the surface of the polishing body 22 is formed.
The dent amount of the portion becomes shorter, and when the dent amount becomes 0, the portion 21a of the window 21 is damaged by dressing. When the portion 21a of the window 21 is damaged, light scattering and the like at the portion 21a increase, so that the accuracy of detection of the polishing end point and the accuracy of the film thickness measurement decrease. For this reason, the detection is switched so that the detection of the polishing end point and the measurement of the film thickness are performed in the portion 21b of the window 21 having the second shortest dent amount in the initial state. Window 21 for polishing end point detection and film thickness measurement
Platen 3 to switch to do in part 21b of
Change the time interval from when the position detection sensor installed in 6 outputs the trigger signal to when the device 39 for measuring the polishing state is operated to an appropriate time interval, and place it on the device 39 for measuring the polishing state. When the portion 21b of the window 21 comes, the device 39 for measuring the polishing state may be operated.

Then, when the polishing step and the dressing step are repeated, the dent amount of the portion 21b of the window 21 becomes zero, and if the dressing damages the portion 21b of the window 21, this time, In the initial state, the detection of the polishing end point and the measurement of the film thickness are performed in the initial state.
Switch to the part. As described above, during dressing, the surface on the side of the object to be polished of the window provided at the opening used for detecting the polishing end point and measuring the film thickness is concave with respect to the surface of the polishing body. Sometimes the part is not scratched.

In the third and fourth embodiments,
The polishing body 22 has a stepped window having a surface with three steps at the opening, but the number of steps may be two or four or more. In that case, the observation of the polishing state can be switched by the number of times corresponding to the number of these steps.

As described above, in the flattening apparatus according to the fourth embodiment using the polishing body according to the third embodiment,
Since the polished body is provided with a window having a stepped surface, even if a part of the window is damaged due to dressing and becomes optically opaque, the window part to be observed by the polishing state measuring device 39 is switched. This makes it possible to detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long period of time as compared with the related art, and the frequency of replacement of the polishing body or the window is reduced, so that there is an effect that the cost for polishing can be reduced.

Next, a polishing body according to a fifth embodiment of the present invention and a planarizing device according to a sixth embodiment of the present invention will be described. FIGS. 4A and 4B show a fifth embodiment of the present invention.
It is a figure showing a polish object by an embodiment. FIG. 4 (a)
FIG. 4B is a top view, and FIG. 4B is a cross-sectional view taken along line FG of FIG. 4A.

The polishing body 42 according to the fifth embodiment has one opening. The parallel-plated window 41 installed in the opening is arranged so that its cross section is oblique, and the amount of depression from the surface of the polishing body differs in the FG direction in FIG. . Thus, the amount of depression of the surface of the window 41 on the side of the object to be polished changes continuously. The amount of depression of the surface of the window on the side of the object to be polished with respect to the surface of the polished body is as follows. Short, 41c is the third shortest, and 41d is the longest.

The flattening device according to the sixth embodiment is different from the flattening device according to the second embodiment (FIG. 2) in that the first flattening device is the same as the flattening device according to the second embodiment.
Instead of the abrasive body (12 in FIG. 2) according to the fifth embodiment,
The polishing body 42 according to the embodiment is installed. However, since the polishing body 42 according to the fifth embodiment has only one opening, only one opening is formed in the surface plate 36 of the flattening apparatus according to the sixth embodiment. It is. The opening of the surface plate 36 overlaps the opening of the polishing body 42. The description of the same parts as those of the flattening device according to the second embodiment will be omitted.

Immediately after the start of polishing, in the initial state, the amount of depression of the surface of the window 41 on the side of the object to be polished with respect to the surface of the polishing body is the shortest.
The portion 41a is used for observing the state of the polished surface. Thereby, of the light emitted from the polishing state measuring device 39, reflected on the polished surface of the silicon wafer 33, and returned to the polishing state measuring device 39, the light passing through the portion 41a of the window 41 is used. The condition of the polished surface is observed. A position detection sensor (not shown) is provided on the surface plate 36 as in the flattening device according to the second embodiment. The platen 36 rotates and reaches the portion 41a of the window 41 installed in the opening on the apparatus 39 for measuring the polishing state from the position of the platen 36 where the position detection sensor outputs a trigger signal. The time interval up to the platen 36
Is determined by the number of rotations. Therefore, similarly to the second embodiment, the time interval is calculated or measured in advance, and after the time has elapsed since the position detection sensor outputs the trigger signal, the apparatus for observing the state of the polished surface is used. 39
Should be operated.

Then, similarly to the second embodiment, the polishing step and the dressing step are repeated.

The surface of the polishing body 42 is shaved every time the dressing is performed.
The dent amount of the portion becomes shorter, and when the dent amount becomes zero, the portion 41a of the window 41 is damaged by dressing. When the portion 41a of the window 41 is damaged, light scattering and the like at the portion 41a increase, so that the accuracy of detection of the polishing end point and the accuracy of film thickness measurement decrease. For this reason, the detection is switched so that the detection of the polishing end point and the measurement of the film thickness are performed in the portion 41b of the window 41 having the second shortest dent amount. Detection of polishing end point and film thickness measurement
In order to switch to the part b, the time interval from when the position detection sensor installed on the surface plate 36 outputs a trigger signal to when the device 39 for measuring the polishing state is operated is set to an appropriate time interval. Device for changing and measuring the polishing state 39
What is necessary is just to operate the apparatus 39 for measuring the polishing state when the portion 41b of the window 41 comes to the top.

Then, by repeating the polishing step and the dressing step, the dent amount of the portion 41b of the window 41 becomes zero, and if the dressing causes the portion 41b of the window 41 to be damaged, this time, Switches the detection of the polishing end point and the film thickness measurement to the portion 41c of the window 41 having the third shortest dent amount. Further, the polishing process and the dressing process are repeated, and the dent amount of the portion 41c of the window 41 becomes zero, and the dressing causes the portion 41c of the window 41 to be damaged. And the measurement of the film thickness are switched to the portion 41d of the window 41 having the longest depression amount. As described above, during dressing, the surface on the side of the object to be polished of the window provided at the opening used for detecting the polishing end point and measuring the film thickness is concave with respect to the surface of the polishing body. Sometimes the part is not scratched.

In the fifth and sixth embodiments, switching is performed at four windows, but the number of switching may be two or three, or four or more. In that case, the observation of the polished state can be switched a number of times corresponding to the number of these portions to be measured.

As described above, in the flattening apparatus according to the sixth embodiment using the polishing body according to the fifth embodiment,
Since a parallel-plate-shaped window is provided on the polished body so that its surface is oblique, even if a part of the window is damaged due to dressing and becomes optically opaque, the window to be observed by the polishing condition measuring device 39 can be used. By switching the portions, it is possible to detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long period of time as compared with the related art, and the frequency of replacement of the polishing body or the window is reduced, so that there is an effect that the cost for polishing can be reduced.

In the flattening devices according to the fourth and sixth embodiments described above, the amount of light received by the device 39 for measuring the polishing state differs from a predetermined set value as in the second embodiment. When also becomes small, provided a control device to switch to the next opening portion 21a, 21b of the window 21,
The switching of 21c and the switching of the portions 41a, 41b, 41c, 41d of the window 41 may be performed.

In the first to sixth embodiments described above, when the amount of depression of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body exceeds 400 μm, the amount of the abrasive that accumulates in the depression is reduced. More. Then, since the abrasive becomes a scatterer and attenuates the light 17 emitted from the polishing state measuring device 39, the accuracy of detection of the polishing end point and the accuracy of film thickness measurement are reduced. For this reason, the dent amount d of the portion of the window through which light from the device 39 for measuring the polishing state passes (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400 μm.
It is preferred that

Next, a polishing body according to a seventh embodiment of the present invention and a flattening apparatus according to an eighth embodiment of the present invention will be described. FIGS. 5A and 5B show the seventh embodiment of the present invention.
It is a figure showing a polish object by an embodiment. FIG. 5 (a)
FIG. 5B is a top view, and FIG. 5B is a cross-sectional view taken along the line HI of FIG.

The polishing body 52 according to the seventh embodiment has one opening. The parallel plate-shaped window 51 installed in the opening has four transparent materials 51a, 51b, 51c, and 51d.
Are laminated with an adhesive force that can be peeled off. The transparent materials 51a, 51b, 51c, 51d are adhered with an adhesive having a releasable adhesive strength or a double-sided tape. By peeling the transparent materials 51a, 51b, 51c, 51d one by one from the upper part, the amount of depression of the window 52 on the polishing object side with respect to the surface of the polishing body 52 changes stepwise.

The flattening device according to the eighth embodiment is the same as the flattening device according to the second embodiment (FIG. 2).
7 instead of the abrasive body (12 in FIG. 2) according to the embodiment.
A polishing body 52 according to the embodiment of FIG. However, since the polishing body according to the seventh embodiment has only one opening, only one opening is formed in the surface plate 36 of the flattening apparatus according to the eighth embodiment. is there.
The opening of the surface plate 36 overlaps the opening of the polishing body. The description of the same parts as those of the flattening device according to the second embodiment will be omitted.

Immediately after the start of polishing, in the initial state, a window in which four transparent materials 51a, 51b, 51c and 51d are laminated is used for observing the state of the polished surface. Thus, of the light emitted from the polishing state measuring device 39, reflected on the polished surface of the silicon wafer 33, and returned to the polishing state measuring device 39, 4
The state of the polished surface is observed by light passing through the window on which the sheets of transparent material 51a, 51b, 51c, 51d are stacked. A mechanism for detecting a polishing end point and measuring a film thickness by using an opening formed in the surface plate 36 and the polishing body 52 with the rotation of the surface plate 36,
The method is the same as in the second embodiment, and a description thereof will be omitted.

Then, similarly to the second embodiment, the polishing step and the dressing step are repeated.

Each time the dressing is performed, the surface of the polishing body is shaved, and the amount of depression of the surface of the transparent material 51a on the object to be polished out of the windows 51 of the opening with respect to the surface of the polishing body 52 decreases. When the value becomes 0, the transparent material 51 is formed by dressing.
The surface of a becomes scratched. When the surface of the transparent material 51a in the window 51 becomes damaged, the transparent material 51a
In this case, the scattering of light and the like increase, so that the accuracy of end point detection and the accuracy of film thickness measurement decrease. Therefore, the laminated windows 51
Then, the portion of the transparent material 51a is peeled off, and the detection of the polishing end point and the measurement of the film thickness are performed so that the transparent material 51b is on the uppermost surface of the window. As a result, the surface of the window 51 is recessed from the surface of the polishing body 52 and the surface of the window 51 is not damaged, so that the end point of polishing or the film thickness measurement can be performed normally. In the flattening device according to the eighth embodiment, the same position of the window 51 of the same opening can be used for detecting the polishing end point or measuring the film thickness, as in the flattening device according to the second embodiment. There is no need to switch the position of the window used for detecting the polishing end point or measuring the film thickness.

When the polishing step and the dressing step are repeated, the amount of depression of the surface of the window 51 on the side of the object to be polished of the transparent material 51b becomes zero, and the dressing damages the transparent material 51b. This time, the portion of the transparent material 51b is peeled off from the window 51, and the detection of the polishing end point and the measurement of the film thickness are performed so that the transparent material 51c is on the uppermost surface of the window. Further, when the polishing step and the dressing step are repeated, the amount of dent of the surface of the transparent material 51c of the window 51 on the side of the object to be polished becomes zero, and the dressing damages the transparent material 51c portion. From window 51, transparent material
The portion 51c is peeled off, and the end point of polishing and the film thickness measurement are performed so that the transparent material 51d is on the uppermost surface of the window 51. As described above, during dressing, the surface on the side of the object to be polished of the window provided at the opening used for detecting the polishing end point and measuring the film thickness is concave with respect to the surface of the polishing body. Sometimes the part is not scratched.

In order to know the timing at which the window portions 51a, 51b, 51c are peeled off, when the amount of light received by the polishing state measuring device 39 becomes smaller than a predetermined set value, the peeling is performed. A control device that outputs a signal indicating the timing of the operation may be provided.

The window 51 has four transparent materials 51a, 51b,
Although a window in which 51c and 51d are stacked is used, a window in which two, three, or five or more transparent materials are stacked may be used. In that case, the observation of the polishing state can be switched the number of times corresponding to the number of these transparent materials.

When the amount of depression of the surface of the window 51 on the side of the object to be polished with respect to the surface of the polishing body 52 exceeds 400 μm, the amount of the abrasive that accumulates in the concave part increases, and the abrasive becomes a scatterer and the polishing state Since the light 17 emitted from the measuring device 39 is attenuated, the accuracy of the detection of the polishing end point and the accuracy of the film thickness measurement are reduced. For this reason, the recess amount d of the portion through which the light from the device 39 for measuring the polishing state of the window 51 passes (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400.
It is preferably μm. Accordingly, it is preferable that the thickness t1 of each of the transparent materials 51a, 51b, and 51c excluding the lowermost transparent material 51d is 0 μm <t1 ≦ 400 μm.

As described above, in the flattening apparatus according to the eighth embodiment using the polishing body according to the seventh embodiment,
Since the window on which the transparent material is laminated is provided on the polishing body, even if the surface of the window on the object to be polished is damaged due to dressing and becomes optically opaque, the transparent material on the uppermost layer of the laminated window is removed. By peeling, it is possible to detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long period of time as compared with the related art, and the frequency of replacement of the polishing body or the window is reduced, so that there is an effect that the cost for polishing can be reduced.

In the first to eighth embodiments described above, the window is directly provided at the opening of the polishing body, but the window does not need to be directly provided at the polishing body. For example, the window may be installed on the surface plate directly or via a jig so as to cover at least a part of the opening of the polishing body.

In the first to eighth embodiments, the openings 13a, 13b, 13c provided in the polishing body 12 and the polishing body 2
2, the opening provided in the polishing body 32, the opening provided in the polishing body 42, and the shape of the hole of the opening provided in the polishing body 52 have a step-like shape. However, these openings may be straight through holes.

In the first to eighth embodiments, the window
11a, 11b, 11c, 21, 41, 51 have glass, acrylic,
A transparent material such as polyurethane, epoxy, PET, vinyl chloride, polycarbonate, polyester, or silicone rubber is used. The polishing characteristics such as the polishing rate and hardness of these transparent materials are preferably equal to the polishing characteristics of the polishing body. Thereby, even when the window and the silicon wafer to be polished are in contact with each other, there is an effect that the polished surface of the silicon wafer is not damaged by the window and polishing is not uniform.

Next, a flattening apparatus according to a ninth embodiment of the present invention will be described. The flattening device according to the ninth embodiment is a modification of the flattening device according to the second embodiment, and the description of the same parts as those of the flattening device according to the second embodiment will be omitted. The flattening apparatus according to the ninth embodiment has one opening formed in the surface plate and the polishing body used for detecting the polishing end point and measuring the film thickness, respectively, and the opening formed in the surface plate. The openings formed in the polishing body overlap with each other.

FIG. 6 is a sectional view showing the vicinity of the opening 66 of the platen 36 of the flattening apparatus according to the ninth embodiment of the present invention. A window support 62 that supports the window 63 is attached to the moving device 61, and a movable window having the window 63 installed at the upper end of the window support 62 is an opening of the surface plate 36.
It is located at 66. Thus, the window 63 is installed on the surface plate 36 via the window support 62 and the moving device 61. As the moving device 61, an electric stage, a piezo stage, or the like is used. The window support 62 has a pipe shape, and the hollow portion of the pipe serves as an optical path for detecting the polishing end point, measuring the film thickness, and the like. Opening of platen 36 to prevent abrasive infiltration
The gap between the window support 62 and the window support 62 is formed by grease (not shown) and / or
Alternatively, it is sealed with an O-ring 64. By moving the window support 62 and the window 63 in the vertical direction in FIG. 6 by the moving device 61, the position of the surface of the window 63 on the polishing object side is moved.

Below the surface plate 36, a device 39 for observing the state of the polished surface and a device 68 for detecting the distance between the surface of the window 63 and the polished surface of the silicon wafer to be polished are arranged. The distance between the surface of the window 63 on the object to be polished and the polishing surface of the object to be polished is the same as the amount of depression of the surface of the window 63 on the object to be polished with respect to the surface of the polishing body 69. The polishing end point is detected and the film thickness is measured by the device 39 for observing the state of the polished surface. As the device 68 for detecting the interval, a sensor using the principle of autofocus, a sensor using the principle of interference, or a signal for irradiating light, receiving reflected light, and controlling the received light amount to be constant. Is used. The computer PC and the stage controller Cnot.
, A motor M of the electric stage is driven to control the distance between the surface of the window 63 on the polishing object side and the polishing surface of the silicon wafer (not shown) as the polishing object. The control of the distance between the surface of the window 63 and the polished surface of the silicon wafer (not shown) by a signal from the device 68 for detecting the distance is performed by setting the computer PC so that the distance is always constant. .

As in the second embodiment, each time one silicon wafer is polished, dressing is performed.
Even during the dressing, the position of the surface of the window 63 is controlled so as to be fixed at the position controlled during the above-described polishing.
After dressing, a silicon wafer to be polished next is attached to the polishing head 32, and polishing is performed. Thus, the polishing step and the dressing step are alternately repeated.

The position of the window 63 is controlled by using a device 68 for detecting the distance between the surface of the window 63 on the side of the object to be polished and the polishing surface of the silicon wafer to be polished. Instead of the detecting device 68, a device for detecting the wear state of the abrasive body 69 may be provided. In that case, the moving device 61 may be controlled so that the surface of the window 63 on the side of the object to be polished is moved downward in FIG. As a device for detecting the wear state of the abrasive body, a stylus type displacement meter, an optical type displacement meter, or the like is used. Further, the position of the window 63 may be controlled using both the device 68 for detecting the interval and the device for detecting the wear state of the abrasive body.

As described above, in the flattening apparatus according to the ninth embodiment, since the position of the surface of the window on the side of the object to be polished is controlled by the moving apparatus, the polishing of the window and the silicon wafer as the object to be polished is performed. The surface of the window on the side of the object to be polished is concave with respect to the surface of the polishing body so as to have a certain distance between the surface and the surface, and the state is maintained even during dressing. Since the surface on the side of the object to be polished is not damaged, it is possible to always detect the polishing end point and measure the film thickness. As a result, the same polishing body can be used for polishing for a long period of time as compared with the related art, and the frequency of replacement of the polishing body or the window is reduced, so that there is an effect that the cost for polishing can be reduced.

In the flattening apparatus according to the ninth embodiment, the distance between the surface of the window 63 and the polished surface of the silicon wafer is controlled by the computer PC so that the distance is always constant. However, unlike this control method, the computer PC estimates the amount of wear of the polished body from the polishing conditions, polishing time, dressing conditions and dressing time, and calculates the distance between the window surface and the polished surface of the silicon wafer. May be controlled.

In the above first to ninth embodiments, 1
It is described that the polishing body is dressed every time the polishing of one silicon wafer is completed. However, the polishing body may be dressed each time polishing of two or more appropriate silicon wafers is completed.

Next, a flattening apparatus according to a tenth embodiment of the present invention will be described. The configuration of the flattening device according to the tenth embodiment of the present invention is the same as that of the flattening device according to the ninth embodiment. In the flattening apparatus according to the tenth embodiment, a position sensor is further provided on the surface plate 36, and the position sensor is used only when the silicon wafer is above the opening 66 of the surface plate (or when the silicon wafer is A signal that is output only when the signal is not above the opening of the platen)
Import to PC. The distance between the surface of the window 63 when the silicon wafer is located above the opening 66 and the silicon wafer and the window 63 with respect to the surface of the polishing body 69 when the silicon wafer is located at other positions. Dynamic control synchronized with the rotation of the surface plate 36 is performed so that the window 63 is moved so that the amount of depression on the surface on the side of the object to be polished becomes longer.

As described above, the dent amount of the window is controlled to be short only when the polishing end point or the film thickness is measured during polishing, and the dent amount is long otherwise. It is not necessary to perform dressing between polishing and polishing. A dressing diamond grindstone etc. is installed together with the polishing head on the polishing body, and dressing is performed simultaneously with polishing (in-situ (in-situ)). Dressing) is possible.

As described above, in the flattening device according to the tenth embodiment, the position of the surface of the window on the side of the object to be polished is controlled by the moving device, so that the dressing diamond grindstone is formed in the opening of the polishing body. When passing over the surface of the polishing body, the amount of depression of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body is long. It is possible to always detect the polishing end point and measure the film thickness without damaging the surface on the object side. As a result, the same polishing body can be used for polishing for a long time as compared with the conventional method, the frequency of replacement of the polishing body or the window is reduced, and it is not necessary to take time for dressing. Since the total time required for polishing is reduced, the cost required for polishing can be reduced.

In the ninth and tenth embodiments described above, when the amount of depression of the surface of the window on the side of the object to be polished with respect to the surface of the polishing body exceeds 400 μm, the amount of the abrasive that accumulates in the depression increases. . Then, since the abrasive becomes a scatterer and attenuates the light 17 emitted from the polishing state measuring device 39, the accuracy of detection of the polishing end point and the accuracy of film thickness measurement are reduced. For this reason, it is preferable that the position of the window is controlled such that the amount of depression d of the window when light from the polishing state measuring device 39 passes is 0 μm <d ≦ 400 μm.

In the ninth and tenth embodiments, the window 63 is made of a transparent material such as glass, acrylic, polyurethane, epoxy, PET, vinyl chloride, polycarbonate, polyester, or silicone rubber.

In the first to tenth embodiments, when the thickness of the window is less than 10% of the thickness of the polishing body, the thickness of the window is reduced, and the window may be deformed. When the window is deformed and optically distorted, the distortion causes the window to have a function as a lens or the like, so that there is a problem that the detection of the polishing end point and the measurement of the film thickness become unstable. For this reason, the amount of the depression is 90% or less of the thickness of the polishing body so that the thickness of the window at the thinnest portion of the window is 10% or more of the thickness of the polishing body. Preferably, there is. Thereby, there is an effect that instability of detection of the polishing end point and instability of measurement of the film thickness due to deformation of the window do not occur.

Next, a flattening apparatus according to an eleventh embodiment of the present invention will be described. The flattening device according to the eleventh embodiment is a modification of the flattening device according to the second embodiment, and the description of the same parts as those of the flattening device according to the second embodiment will be omitted. The flattening apparatus according to the eleventh embodiment has one opening formed in the surface plate and the polishing body used for detection of the polishing end point and measurement of the film thickness, respectively, and the opening formed in the surface plate. The openings formed in the polishing body overlap with each other.

FIG. 7A is a sectional view showing the vicinity of an opening of a planarizing device according to an eleventh embodiment of the present invention.
(B) is a sectional view showing a state near the opening of the planarizing device according to the eleventh embodiment of the present invention when an object to be polished comes over the opening. A window 72 made of transparent rubber is attached to the upper end of the window fixing cylinder 71, and a window 73 made of glass is attached to the lower end. Further, an air pressure control device 74 is connected to the window fixing cylinder 71 to increase / decrease the pressure inside the window fixing cylinder 71. Polishing body 75 provided with openings according to the size of transparent rubber window 72
It is installed by being pasted on 36. The surface of the transparent rubber window 72 on the side of the object to be polished is depressed with respect to the surface of the polishing body 75 when the pressure in the window fixing cylinder 71 is reduced (normal pressure).
The window fixing cylinder 71 is installed in an opening 77 of the surface plate 36. When the pressure in the window fixing cylinder 71 is increased by the air pressure control device 74, the transparent rubber window 72 attached to the upper end of the window fixing cylinder 71 expands upward. When the transparent rubber window 72 expands upward, it slightly jumps out of the surface of the polishing body 75, but when the silicon wafer 33 is over the opening 77, as shown in FIG. The surface of the transparent rubber window 72 on the object to be polished is in close contact with the polished surface of the silicon wafer 33.
As described above, the pneumatic pressure control device 74 and the window fixing cylinder 71 adjust the pressure in the window fixing cylinder 71 so that the transparent rubber window 72 is
And functions as a moving device for moving the surface of the transparent rubber window 72 on the polishing object side in the vertical direction in FIG. Therefore, the transparent rubber window 72 is installed on the surface plate 36 via the window fixing cylinder 71 having a function as a moving device.

A position sensor is provided on the surface plate 36. As the position sensor, a silicon wafer is used as the opening 77 of the surface plate.
Using a device that outputs a signal only when it is above the surface (or only when the silicon wafer is not above the opening of the surface plate)
The signal from the position sensor is taken into a computer PC. When the silicon wafer is located above the opening 77, the pressure in the window fixing cylinder 71 is increased, and when the silicon wafer is at any other position, the pressure in the window fixing cylinder 71 is reduced (normal pressure). The dynamic control synchronized with the rotation of the surface plate 36 is performed as much as possible.
With such control, when the silicon wafer is located above the opening 77, the surface of the transparent rubber window 72 on the side of the object to be polished contacts the surface of the silicon wafer 33, and is located at other positions. At this time, the surface of the transparent rubber window 72 on the polishing object side is recessed with respect to the surface of the polishing body 75.

A device 39 for observing the state of the polished surface is arranged below the surface plate 36, and the detection of the polishing end point and the measurement of the film thickness are performed in the same manner as in the ninth embodiment.

By controlling the position of the surface of the window 72 as described above, it is not necessary to perform dressing of the polishing body 75 between polishing and in-situ (in-situ) dressing is possible.

The surface of the transparent rubber window 72 on the side of the object to be polished comes into contact with the silicon wafer 33 when the polishing end point is detected or the film thickness is measured. The surface on the object side may not be in contact with the silicon wafer 33. In this case, when the amount of depression of the surface of the transparent rubber window 72 on the polishing object side with respect to the surface of the polishing body 75 exceeds 400 μm, the amount of the abrasive that accumulates in the depression increases. Then, since the abrasive becomes a scatterer and attenuates the light 17 emitted from the polishing state measuring device 39, the accuracy of detection of the polishing end point and the accuracy of film thickness measurement are reduced. For this reason, the recess amount d of the portion through which light from the device 39 for measuring the polishing state of the transparent rubber window 72 (the portion used for detecting the polishing end point and measuring the film thickness) is 0 μm <d ≦ 400 μm. Is preferred.

As described above, in the flattening device according to the eleventh embodiment, the pressure in the window fixing cylinder 71 is controlled to control the position of the surface of the window on the side of the object to be polished. When the diamond whetstone passes over the opening of the polishing body, the amount of depression of the surface of the window on the polishing object side with respect to the surface of the polishing body increases. Therefore, even if the dressing is performed while the object to be polished is being polished, the surface of the window on the object to be polished is not damaged by the dressing, and the detection of the polishing end point and the measurement of the film thickness can always be performed. As a result, the same polishing body can be
It can be used for polishing, the frequency of replacement of the polishing body or window is reduced, and it is not necessary to take time for dressing, so the total time required for polishing a large number of objects to be polished is reduced, so that the cost of polishing is reduced. There is an effect that it can be reduced.

In the above-described first to eleventh embodiments, the device 39 for observing the state of the polished surface provided under the surface plate 36 is a reflection spectral characteristic (reflection spectral spectrum).
It is preferable to use an apparatus for detecting the polishing end point and measuring the film thickness. The reflection spectrum measured by the device 39 for observing the state of the polished surface is compared with a reference spectrum obtained by a simulation or the like in a computer (not shown) to calculate the film thickness or detect the polishing end point. In addition, as the device 39 for observing the state of the polished surface,
Instead of the device for detecting the polishing end point and measuring the film thickness from the above-mentioned reflection spectral characteristics (reflection spectral spectrum), the device for detecting the polishing end point or measuring the film thickness from a change in reflectance at a specific wavelength, or a polished surface A device that detects the polishing end point or measures the film thickness by subjecting the captured image to image processing using a CCD camera or the like and subjecting the captured image to image processing may be used.

In the first to eleventh embodiments, the transmittance of the windows 11a, 11b, 11c, 21, 41, 51, 63, 72, 77 is preferably 22% or more. Thereby, the attenuation of the intensity of light for measuring the polishing state passing through the window is reduced, so that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness do not decrease.

In the first to eleventh embodiments, an antireflection film is formed on the surface of the window 11a, 11b, 11c, 21, 41, 51, 63, 72, 77 opposite to the object to be polished. Is preferred. Thereby, the amount of light for measuring the polishing state passing through the window is reflected by the opposite surface of the object to be polished of the window, and the attenuation of the light intensity for measuring the polishing state is reduced. Therefore, there is an effect that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness do not decrease.

In the first to eleventh embodiments, the intensity of the light 17 emitted from the device 39 for measuring the polishing condition and the intensity of the light 17 emitted from the device 39 for measuring the polishing condition are passed through the window, and the window and the silicon are measured. A device that passes through the abrasive 35 between the wafers 33, reflects off the polished surface of the silicon wafer 33, passes through the abrasive 35 again between the window and the silicon wafer 33, passes through the window again, and measures the polishing state. Regarding the relationship of the intensity of the light returning to 39, the ratio of the intensity of the light returning to the device to the intensity of the light 17 emitted from the device 39 for measuring the polishing state is preferably 5% or more. As a result, the intensity of the light returning to the apparatus for measuring the polishing state does not decrease, so that there is an effect that the detection accuracy of the polishing end point and the measurement accuracy of the film thickness by the apparatus for measuring the polishing state do not decrease.

In the first to eleventh embodiments, the polishing body is dressed. However, when a non-foaming material is used for the polishing body, the dressing may not be necessary. Even with such a polishing body that does not require dressing, the surface of the polishing body is shaved with the polishing of the object to be polished. Therefore, even when the polishing body that does not require dressing is used in the first to eleventh embodiments, a window or a polishing body is required. There is an effect that the frequency of exchanging is reduced, and the cost required for polishing can be reduced.

FIG. 8 is a flowchart showing a semiconductor device manufacturing process. When the semiconductor device manufacturing process is started, first, in step S200, an appropriate processing step is selected from the following steps S201 to S204. According to the selection, the process proceeds to any of steps S201 to S204.

Step S201 is an oxidation step for oxidizing the surface of the silicon wafer. Step S202 is a CVD step of forming an insulating film on the surface of the silicon wafer by CVD or the like. Step S203 is an electrode forming step of forming electrodes on the silicon wafer by steps such as vapor deposition. Step S204 is an ion implantation step of implanting ions into the silicon wafer.

After the CVD step or the electrode forming step, the process proceeds to step S205. Step S205 is a CMP process. CMP
In the process, the planarization device according to the present invention performs planarization of an interlayer insulating film, formation of a damascene by polishing a metal film on the surface of a semiconductor device, and the like.

After the CMP step or the oxidation step, step S
Continue to 206. Step S206 is a photolithography process. In the photolithography process, a resist is applied to a silicon wafer, a circuit pattern is printed on the silicon wafer by exposure using an exposure apparatus, and the exposed silicon wafer is developed. Further, the next step S207 is an etching step in which portions other than the developed resist image are etched away, and then the resist is peeled off to remove unnecessary resist after etching.

Next, it is determined in step S208 whether all necessary steps have been completed. If not, the process returns to step S200, and the previous steps are repeated to form a circuit pattern on the silicon 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 planarization apparatus according to the present invention is used in the CMP process, the accuracy of detecting the polishing end point or the accuracy of measuring the film thickness in the CMP process is improved. The yield in 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.

Note that the planarization 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.

A semiconductor device according to the present invention is manufactured by the semiconductor device manufacturing method according to the present invention. Thus, there is an effect that the semiconductor device can be manufactured at a lower cost than the conventional semiconductor device manufacturing method, and the manufacturing cost of the semiconductor device can be reduced.

[0132]

Embodiments of the present invention will be described below.

Example 1 As a polishing body 12 (FIG. 1) according to the first embodiment, the layer below the polishing body was a SUBA40 manufactured by Rodel.
0, a two-layer polished body (hereinafter referred to as IC1000 / SUBA400) having an upper layer made of Rodel IC1000 was used.

The amount of depression from the surface of the polishing body to the surface of the window on the side of the object to be polished is 0.15 mm in the opening 13a and in the opening 13b.
The windows 11a, 11b and 11c made of polyurethane were arranged so as to be 0.3 mm and 0.45 mm in the opening 13c.

After that, the above-mentioned polishing body was set on the surface plate of the flattening apparatus according to the second embodiment (FIG. 2). Thermal oxide film
Polishing of a 6-inch silicon wafer formed at 1 μm is performed under the following conditions, and the residual film thickness of the silicon wafer is measured in-situ by a device 39 for measuring the polishing state using the window 11a of the opening 13a.
u measured.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a # 100 diamond grindstone
Dressed for 1 minute.

Each time, a new 6 μm thermal oxide film was formed.
The above polishing step and dressing step were repeated using an inch silicon wafer. FIG. 9 is a graph of a reflection spectrum from the silicon wafer surface measured in-situ at a certain moment during polishing, and a reflection spectrum obtained by obtaining a curve (a) out of the curves in the graph of FIG. 9. In the graph of FIG. 9, the horizontal axis is wavelength, and the vertical axis is a silicon wafer on which aluminum is deposited and placed on the window of the polishing body with ion-exchanged water interposed instead of the abrasive. The reflection spectrum of the light returning to the polishing state measuring device 39 at this time is defined as a reference reflection spectrum, and the intensity ratio of the measured reflection spectrum to the reference reflection spectrum. In-situ measurement of the residual film thickness of the thermal oxide film on the silicon wafer was possible from the waveform fitting by simulation. However, the dressing after polishing of the 120th silicon wafer started to cause scratches in the window, and the reflection spectrum obtained by polishing of the 150th silicon wafer became as shown by the curve (b) in FIG. The probability of errors in measurement has increased.

Then, when the in-situ measurement was performed by switching to the window 11b of the opening 13b in which the dent amount in the initial state was 0.3 mm, the in-situ measurement without error was possible as before. Was.

Further, the dressing process after the polishing of the 260th silicon wafer was performed.
1b is scratched, and the window 11b is polished by polishing the 280th silicon wafer.
The measurement became difficult due to a decrease in the transmittance of the sample.

Again, the opening 13 with the recess amount of 0.45 mm in the initial state
When switching to the window 11c of c and performing in-situ measurement, in-situ measurement was possible as before.

Finally, in the window 11c of the opening 13c, the polishing process and the dressing process of the 450th silicon wafer are performed.
In-situ measurement was possible.

Example 2 A polishing body IC1000 / SUBA400 manufactured by Rodel was used as a polishing body according to the third embodiment of the present invention, and one opening was provided in the polishing body.

A window 21 made of polyurethane shown in FIG. 3 was provided. The amount of depression between the surface of the polishing body 22 and the surface of the window 21 on the side of the object to be polished was set to 0.15 mm, 0.3 mm, and 0.45 mm in each of the portions 21a, 21b, and 21c.

After that, the polishing body 22 was set on the surface plate of the flattening apparatus according to the fourth embodiment of the present invention. Polishing of the 6-inch silicon wafer on which the thermal oxide film was formed was performed under the following conditions, and the remaining film thickness on the silicon wafer was measured by the apparatus 39 for measuring the polishing state using the portion 21a of the window 21.
-Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a # 100 diamond grindstone
Dressed for 1 minute.

Each time, a new 6 μm thermal oxide film was formed.
When the above polishing step and dressing step were repeated using an inch silicon wafer, the dressing after polishing of the 120th silicon wafer began to damage the portion 21a of the window 21. The probability of an error occurring in in-situ measurement increased due to the decrease in the transmittance of the portion 21a.

Therefore, when the indentation amount was switched to the portion 21b where the dent amount was 0.3 mm in the initial state and in-situ measurement was performed, in-situ measurement without error was possible as before.

Further, when the dressing process was performed after the 260th silicon wafer was polished, scratches began to be formed on the portion 21b of the window 21. When the 280th silicon wafer was polished, the transmission through the portion 21b of the window 21 was started. The probability of errors in in-situ measurement increased due to the decrease in the rate.

When the in-situ measurement was performed again by switching to the portion 21c of the window 21 in which the dent amount in the initial state was 0.45 mm, the in-situ measurement without error was possible as before. Was.

Finally, in the portion 21c of the window 21, in-situ measurement was possible up to the polishing of the 450th silicon wafer.

Example 3 A polishing body IC1000 / SUBA400 manufactured by Rodel was used as a polishing body according to the fifth embodiment of the present invention, and one opening was provided in the polishing body.

As shown in FIG. 4, windows 41 made of polyurethane were arranged diagonally. The amount of dent from the surface of the polishing body 42 to the surface of the window on the side of the object to be polished is a minimum of 0.1 mm (portion 41a),
The maximum was 0.5 mm (41d part).

Thereafter, the polishing body 42 was set on the surface plate of the flattening apparatus according to the sixth embodiment of the present invention. Polishing of the 6-inch silicon wafer on which the thermal oxide film was formed was performed under the following conditions, and the remaining film thickness on the silicon wafer was measured by the apparatus 39 for observing the polishing state using the portion 41a of the window 41.
-Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min.

The average polishing rate at this time was 430 nm / min. After polishing, use a # 100 diamond grindstone
Dressed for 1 minute.

Each time, a new 6 μm thermal oxide film was formed.
When the above polishing step and dressing step were repeated using an inch silicon wafer, the dressing after polishing of the 50th silicon wafer caused a decrease in the transmittance of the portion 41a of the window 41, and the 70th silicon wafer The probability that an error occurred in the in-situ measurement due to a decrease in transmittance during polishing was increased.

Then, when the in-situ measurement was performed by switching to the portion 41b at which the same transmittance as in the initial stage of polishing was obtained, in-situ measurement was possible as before.

Further, the dressing after polishing of the 110th silicon wafer caused a decrease in transmittance, and the 140-th silicon wafer caused a decrease in transmittance due to the decrease in transmittance.
The probability of errors occurring in situ measurement has increased.

Again, the window 41 from which the same transmittance as the initial one is obtained
When the in-situ measurement was performed by switching to the portion 41c, the in-situ measurement was possible without error as before.

By repeating the above operation, in-situ measurement was finally possible up to the polishing of the 650th silicon wafer.

[Embodiment 4] In a flattening apparatus (FIG. 6) according to a ninth embodiment of the present invention, a window support 62 is attached to an electric stage 61 having a stroke of 10 mm, and an acrylic window 63 is provided at the upper end thereof. Placed.

An apparatus 39 for observing a polishing state is provided below the surface plate 36.
A device 68 for detecting the distance between the surface of the window on the object to be polished and the surface of the object to be polished is provided. As the device 68 for detecting the interval, a sensor using an autofocus mechanism was used.

Next, a polishing body 69 (IC1000 / SUBA400 manufactured by Rodel) provided with an opening corresponding to the size of the window 63 was set on the surface plate 36. Window 63 by signal from interval detecting device 68
Is set such that the distance between the surface of the window 63 on the side of the object to be polished and the polished surface of the silicon wafer is always controlled to 0.2 mm.

Thereafter, the 6-inch silicon wafer on which the thermal oxide film was formed to a thickness of 1 μm was continuously polished 150 sheets at a time under the following conditions, and the remaining film thickness of the silicon wafer was measured by the apparatus 39 for measuring the polishing state. Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min.

After the polishing, dressing was performed for 1 minute with a diamond grindstone having an abrasive size of # 100.

As a result, the thickness of the polished body before and after the polishing was measured. As a result, the polished body was worn by 0.17 mm by polishing and dressing, but the window 63 was not damaged.

FIG. 10 is a graph of the reflection spectrum from the silicon wafer surface measured in-situ at a certain moment during polishing. In the graph of FIG. 10, the horizontal axis is wavelength, and the vertical axis is a silicon wafer on which aluminum has been formed and placed on the window of the polishing body with ion-exchanged water interposed instead of the abrasive. The reflection spectrum of the light returning to the polishing state measuring device 39 at this time is defined as a reference reflection spectrum, and the intensity ratio of the measured reflection spectrum to the reference reflection spectrum. In all of the polishing of 150 silicon wafers, a reflection spectral spectrum as shown by the curve (a) in FIG. 10 was obtained at a certain moment after the same time elapsed from the start of polishing, and good in-situ measurement was performed. .

[Embodiment 5] In the planarizing apparatus according to the tenth embodiment of the present invention, when the window 63 is located below the silicon wafer, the surface of the window on the side of the object to be polished and the object to be polished are The control was performed such that the distance between the surface of the window and the polished surface was 0.5 mm, and the distance between the surface of the window on the polished object side and the polished surface of the polished object was 0.5 mm when it was at a position other than that. The flattening device of the fifth embodiment has the same configuration as the flattening device of the fourth embodiment.

Thereafter, the 6-inch silicon wafer on which the thermal oxide film was formed to a thickness of 1 μm was continuously polished 150 sheets at a time under the following conditions, and the residual film thickness of the silicon wafer was reduced by an apparatus 39 for observing the polishing state. Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min, dressing conditions: 1 minute for each polishing of one silicon wafer with a diamond grindstone of abrasive grain size # 100.

As a result, the thickness of the polished body before and after polishing was measured, and the polished body was worn by 0.15 mm by polishing and dressing, but no scratch was generated on the window 63. In addition, in all of the polishing of 150 silicon wafers, a reflection spectral spectrum as shown by the curve (b) in FIG. 10 was obtained at a certain moment when the same time elapsed from the start of polishing, and good in-situ measurement was performed. Was done.

[Embodiment 6] In the flattening apparatus according to the eleventh embodiment of the present invention, the upper end of the window fixing cylinder 71 has a thickness
A 0.2 mm transparent rubber window 72 was attached, and a glass window 73 was attached to the lower end.

A polishing body 75 (IC1000 / SUBA400 of Rodel) provided with an opening in accordance with the size of the transparent rubber window 72 is placed on a surface plate 36.
And then a transparent rubber window 72 at reduced pressure (normal pressure).
The distance from the surface of the object to be polished to the surface of the
The window fixing cylinder 71 was arranged in the opening 77 of the surface plate 36 so as to be 0.6 mm.

When the silicon wafer 33 is above the opening 77, the pressure in the window fixing cylinder 72 is increased, and the surface of the transparent rubber window 72 on the object to be polished is in close contact with the polished surface of the silicon wafer 33. Was set as follows.

Thereafter, the 6-inch silicon wafer on which the thermal oxide film was formed to a thickness of 1 μm was continuously polished 150 sheets at a time under the following conditions, and the remaining film thickness of the silicon wafer was measured by an apparatus 39 for measuring the polishing state. Measured in situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min, dressing conditions: 1 minute for each polishing of one silicon wafer with a diamond grindstone of abrasive grain size # 100.

As a result, the thickness of the polished body before and after the polishing was measured. As a result, the polished body was worn by 0.16 mm by polishing and dressing, but the window 72 was not damaged. In addition, in all polishing of 150 silicon wafers, a reflection spectral spectrum as shown by a curve (c) in FIG. 10 was obtained at a certain moment when the same time had elapsed from the start of polishing, and good in-situ measurement was performed. Was done.

Comparative Example 1 A polishing body IC1000 / SUBA400 manufactured by Rodel was used as a polishing body, and one opening was provided in the polishing body. A window made of polyurethane was placed at the opening of the polishing body so that the amount of depression from the surface of the polishing body to the surface of the window on the side to be polished was 10 μm or less.

Next, the above-mentioned polishing body was set on the surface plate of the flattening apparatus according to the second embodiment (FIG. 2). Thereafter, polishing of the 6-inch silicon wafer on which the thermal oxide film was formed to 1 μm was polished under the following conditions to reduce the residual film thickness of the silicon wafer.
Measured in-situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min.

At this time, the average polishing rate was 430 nm / min.

After the polishing was completed, dressing was performed for one minute with a diamond grindstone having an abrasive grain size of # 100. As a result, the surface of the window on the object to be polished was scratched and became opaque. At this time, the total transmitted light amount of the light transmitted through the window was 5% or less of the total transmitted light amount before dressing (when the surface of the window on the polishing object side was not damaged).

The second polishing was performed under the same polishing conditions as described above, but the in-situ measurement of the residual film thickness on the silicon wafer was impossible.

[Comparative Example 2] A polishing body IC1000 / SUBA400 manufactured by Rodel was used as a polishing body, and one opening was provided in the polishing body. A window made of acrylic was placed at the opening of the polishing body such that the recess from the surface of the polishing body to the surface of the window on the side of the object to be polished was 0.1 mm.

Next, the above-mentioned polishing body was attached to the surface plate of the flattening apparatus according to the second embodiment (FIG. 2).

Thereafter, 150 6-inch silicon wafers on which a thermal oxide film was formed were continuously polished under the following conditions.
The residual film thickness of the silicon wafer was measured in-situ.

Polishing head rotation speed: 50 rpm, surface plate rotation speed: 5
0 rpm, load on the polishing head: 2.4 × 10 ⁴ Pa, swing of the polishing head: none, polishing time: 90 seconds, polishing agent: SS25 manufactured by Cabot, diluted twice with ion-exchange water, polishing agent flow rate: 200ml
/ Min, dressing conditions: 1 minute for each polishing of one silicon wafer with a diamond grindstone of abrasive grain size # 100.

As a result, when the number of polished sheets was 17, the window was damaged. When the polishing was further continued, the amount of reflected light from the silicon wafer was attenuated at the 53rd wafer, and in-situ measurement became difficult. When I checked the window, it looked like a cloudy glass due to a dressing scratch. From the measurement of the thickness of the polished body before and after polishing, the polished body was worn by 0.05 m due to polishing and dressing.

[0192]

As described above, according to the polishing body and the flattening apparatus of the present invention, the surface of the window on the side of the object to be polished is recessed with respect to the surface of the polishing body, and the amount of the recess is stepwise. Or it is changing continuously. Then, when observing the polished state of the object to be polished by a device for measuring the polished state by optically observing the polished surface of the object to be polished through the window, when the polished state of the object to be polished is not damaged, When the window or that portion of the window is damaged by dressing or polishing using an unflawed part, observation of the polishing state of the object to be polished by an apparatus for measuring the polishing state in the initial state. Switch to a window or window part with different dents and no scratches. Thus, in-situ measurement of the polished state can be performed, and the frequency of replacement of the polished body or window can be reduced, so that there is an effect that the cost required for polishing can be reduced.

Further, according to the flattening device of the present invention,
There is a moving device for moving the position of the surface of the window on the side of the object to be polished. Then, when observing the polished state of the object to be polished by an apparatus for measuring the polished state by optically observing the polished surface of the object to be polished through the window, the surface of the window on the object to be polished and the object to be polished are observed. By keeping the distance between the polished surface of the object and the wear of the polished body surface at a constant value,
In addition, the distance between the surface of the window and the surface of the polishing body is dynamically controlled in synchronization with the rotation of the surface plate. Thereby, the surface of the window on the object to be polished is not damaged by dressing or polishing, and in-situ measurement of the polished state can be performed, so that the frequency of replacement of the polished body or the window can be reduced. This has the effect that the cost required for polishing can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a polishing body according to a first embodiment of the present invention. 1 (a) is a top view, FIG. 1 (b) is a cross-sectional view of the A-O portion of FIG. 1 (a), and FIG. 1 (c) is a cross-sectional view of the B-O portion of FIG. 1 (a). FIG. 1C is a cross-sectional view of a portion C-O in FIG. 1A.

FIG. 2 is a schematic configuration diagram of a flattening device according to a second embodiment of the present invention.

FIG. 3 is a view showing a polishing body according to a third embodiment of the present invention. FIG. 3A is a top view, and FIG. 3B is a cross-sectional view taken along the line D-E in FIG. 3A.

FIG. 4 is a view showing a polishing body according to a fifth embodiment of the present invention. FIG. 4A is a top view, and FIG. 4B is a cross-sectional view taken along line FG of FIG. 4A.

FIG. 5 is a view showing a polishing body according to a seventh embodiment of the present invention. FIG. 5A is a top view, and FIG. 5B is a cross-sectional view of the HI portion in FIG. 5A.

FIG. 6 is a sectional view showing the vicinity of an opening 66 of a surface plate 36 of a flattening apparatus according to a ninth embodiment of the present invention.

FIG. 7 (a) is a cross-sectional view of the vicinity of an opening 77 of a surface plate 36 of a flattening device according to an eleventh embodiment of the present invention.
FIG. 7B is a diagram showing a state when the object to be polished comes over the opening.

FIG. 8 is a flowchart showing a semiconductor device manufacturing process.

FIG. 9 is a reflection spectrum obtained by in-situ measurement at a certain moment during polishing. Curve (a) is in-
Curve (b) is a reflection spectrum when measurement is difficult in Example 1 when situ measurement is possible.

FIG. 10 is a reflection spectrum obtained by in-situ measurement at a certain moment during polishing. Curve (a) is Example 4,
The curve (b) is the reflection spectrum in Example 5, and the curve (c) is the reflection spectrum in Example 6.

FIG. 11 is a conceptual diagram of a planarization technique in a semiconductor manufacturing process, and is a cross-sectional view of a semiconductor device. FIG.
(A) is an example in which an interlayer insulating film on the surface of a semiconductor device is flattened. FIG. 11B shows an example in which a metal film on the surface of a semiconductor device is polished to form a so-called damascene.

FIG. 12 is a schematic configuration diagram of a conventional flattening apparatus used for CMP.

[Explanation of symbols]

 11a, 11b, 11c, 21, 41, 51, 63 Windows 13a, 13b, 13c, 38, 66, 77 Openings 12, 22, 42, 52, 69, 75, 137 Abrasive bodies 31, 131 Abrasive members 32, 132 Polishing head 33, 133 Object to be polished (silicon wafer) 34, 134 Abrasive supply unit 35, 135 Abrasive (slurry) 36, 136 Surface plate 39, 139 Device for observing the polishing state 61 Moving device 62 Window support 64 O Ring 68 Device for detecting the interval 71 Window fixing cylinder 72 Transparent rubber window 73 Glass window 74 Pneumatic control device 121 Silicon wafer 122 Interlayer insulating film 123 Metal film 124 Semiconductor device

Claims (29)

[Claims] 1. A load is applied between the polishing body and the object to be polished in a state where an abrasive is interposed between the object to be polished and the object to be polished installed on a surface plate, and The polishing body used for a planarization device for polishing the object to be polished by relative movement has one or more openings, and a window provided in the opening, and has a surface with respect to the surface of the polishing body. The surface of the window on the side of the object to be polished is concave, and the amount of the concave changes stepwise or continuously. 2. The polishing body according to claim 1, wherein the amount of dent changes stepwise by varying the amount of dent for each of the openings. 3. The polishing body according to claim 1, wherein the amount of the depression changes stepwise by changing the amount of the depression at two or more portions in the same opening. 4. The method according to claim 1, wherein the window is a transparent plate having a parallel plate shape, and the amount of the recess is continuously changed by the window being installed obliquely with respect to the surface of the polishing body. The polishing body according to claim 1, wherein 5. The transparent material according to claim 5, wherein the window is a parallel plate-shaped transparent plate formed by laminating two or more transparent materials, and the transparent material is laminated with an adhesive force enough to be peelable. The polishing body according to claim 1, wherein the amount of the dent changes stepwise by peeling off one by one. 6. The minimum dent amount dmin of the dent amounts is:
6. The polishing body according to claim 1, wherein 0 μm <dmin ≦ 400 μm. 7. A maximum dent amount dmax of the dent amounts is:
0 μm <dmax ≦ 90% of the thickness of the polishing body, and the minimum thickness tmin of the window is tmin ≧ 10% of the thickness of the polishing body. The polishing body according to any one of claims 1 to 5, characterized in that: 8. The polishing body according to claim 1, wherein a transmittance of at least a part of the window is 22% or more. 9. The polishing body according to claim 1, wherein an anti-reflection film is formed on a surface of said window opposite to said object to be polished. 10. A load is applied between the polishing body and the object to be polished in a state in which an abrasive is interposed between the object to be polished and the object to be polished provided on a surface plate, and In the flattening device for polishing the object to be polished by relative movement, one or more openings formed in the surface plate, one or more openings formed in the polishing body, and A window installed on the platen so as to cover at least a part of the opening formed in the polishing body, and a polishing surface of the object to be polished optically through the window. An apparatus for observing and measuring a polishing state, wherein the opening formed in the polishing body and the opening formed in the surface plate are overlapped with each other with respect to a surface of the polishing body. The surface of the window on the side of the object to be polished is concave, and the amount of the concave Flattening device, characterized in that manner or continuously changed. 11. The flattening apparatus according to claim 10, wherein the amount of the dent changes stepwise by changing the amount of the dent for each of the openings formed in the polishing body. 12. The flattening apparatus according to claim 10, wherein the amount of the dent changes stepwise by changing the amount of the dent at two or more portions in the same opening. 13. The method according to claim 13, wherein the window is a parallel plate-shaped transparent plate, and the amount of the depression is continuously changed by the window being installed obliquely with respect to the surface of the polishing body. The flattening device according to claim 10, wherein 14. The window is a parallel plate-shaped transparent plate formed by laminating two or more transparent materials, wherein the transparent material is laminated with an adhesive force enough to be peelable. 11. The flattening apparatus according to claim 10, wherein the amount of the dent changes stepwise by peeling off one by one. 15. The dent amount d of a portion of the window through which light from the apparatus for measuring the polishing state passes is 0 μm <d.
The flattening device according to any one of claims 10 to 14, wherein ≤ 400 µm. 16. A maximum dent amount dmax among the dent amounts.
Is 0 μm <dmax ≦ 90% of the thickness of the polishing body, and the minimum thickness tmin of the window thickness is tm
15. The flattening apparatus according to claim 10, wherein in ≧ 10% of the thickness of the polishing body. 17. A flattening apparatus according to claim 10, wherein said window is made of a resin having a polishing characteristic equivalent to that of said polishing body. 18. A load is applied between the polishing body and the object to be polished in a state where an abrasive is interposed between the object to be polished and the object to be polished provided on the surface plate, and In the flattening device for polishing the object to be polished by relative movement, one or more openings formed in the surface plate, one or more openings formed in the polishing body, and A window installed so as to cover at least a part of the formed opening; a device for optically observing a polishing surface of the object to be polished through the window to measure a polishing state; and A moving device for moving the position of the surface on the side of the object to be polished, wherein the opening formed in the polishing body and the opening formed in the surface plate are overlapped, and the window is It is installed on the surface plate via the moving device. Flattening device. 19. An apparatus for detecting an interval between a surface of the window on the side of the object to be polished and the surface of the object to be polished, an apparatus for detecting a state of wear of the polished body, or an apparatus for detecting both of them. 19. The flattening device according to claim 18, further comprising: 20. The flattening apparatus according to claim 19, further comprising a control device for controlling an interval between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished. 21. The control device according to claim 19, wherein the polishing condition, the polishing time,
21. The method according to claim 20, wherein a wear amount of the polishing body is predicted from dressing conditions and a dressing time, and an interval between a surface of the window on the polishing object side and a polishing surface of the polishing object is controlled. The flattening device according to any one of the preceding claims. 22. The moving device according to claim 21, wherein the control device controls the moving device so that a distance between a surface of the window on the side of the object to be polished and a polishing surface of the object to be polished is constant. 21. The flattening device according to 20. 23. The apparatus according to claim 23, wherein the control device controls an interval between a surface of the window on the polishing object side and a polishing surface of the polishing object in synchronization with rotation of the platen. 2
0. The flattening apparatus according to 0. 24. The apparatus according to claim 18, wherein a distance d between the surface of the window on the side of the object to be polished and the surface of the object to be polished is 0 μm ≦ d ≦ 400 μm. The flattening device according to any one of the preceding claims. 25. A distance d between the surface of the window on the side of the object to be polished and the polishing surface of the object to be polished is 0 μm ≦ d ≦ 90% of the thickness of the polished body, and The thickness of the window t
24. The flattening apparatus according to claim 18, wherein t ≧ t is 10% of the thickness of the polishing body. 26. Light emitted from the apparatus for measuring a polishing state passes through the window, passes through the polishing agent between the window and the object to be polished, and is polished on the polishing surface of the object to be polished. Reflected, passes through the abrasive again between the window and the object to be polished, passes through the window again, returns to the apparatus for measuring the polishing state, and exits from the apparatus for measuring the polishing state. The ratio of the intensity of light returning to the apparatus for measuring the polishing state to the intensity of light is 5% or more.
5. The flattening device according to any one of 5. 27. An anti-reflection film is formed on a surface of the window opposite to the object to be polished.
The flattening apparatus according to any one of 0 to 26. 28. A method of manufacturing a semiconductor device, comprising a step of flattening a surface of a semiconductor silicon wafer by using the flattening apparatus according to claim 10. 29. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 28.