JP2001287158A - Polishing member, polishing machine, adjusting method, measuring method, semiconductor device manufacturing method, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a transparent member with a different material from that of the polishing member needs to be disposed on a portion as a window because a polishing pad is not transparent in general, in forming a measuring window on the polishing member for optical measurement to measure remaining film thickness in a CMP apparatus, and that there is a high risk of a difference in a polishing speed, uneven polishing, and generation of damage because the material generally has different mechanical properties from the polishing member. SOLUTION: This polishing member for polishing machine polishes a polishing object by relatively moving the polishing member and the polishing object with the polishing liquid intervened between the polishing member and the polishing object. A measuring window plate for optically measuring the polishing surface of the polishing object is fitted into the polishing member, an interval between the uppermost front surface of the polishing member and the surface of the uppermost front surface side of the window plate in an unloaded time is set larger than the amount of compressive deformation of the polishing member, and permeability of a measuring beam is adjusted to 10% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing member and a polishing apparatus, particularly a polishing member suitable for use in a CMP apparatus for flattening and polishing a semiconductor device performed in a process of manufacturing a semiconductor device such as ULSI. The present invention relates to a polishing apparatus, an adjusting method, a measuring method, a semiconductor device manufacturing method, and a semiconductor device.

[0002]

2. Description of the Related Art As the degree of integration and miniaturization of semiconductor integrated circuits increases, the number of steps in a semiconductor manufacturing process increases and becomes more complicated. Along with this, the surface of a semiconductor device is not necessarily flat. The presence of a step on the surface causes disconnection of the wiring, an increase in local resistance, etc., 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, the light source wavelength of optical lithography has been shortened with the increase in the degree of integration and miniaturization of semiconductor integrated circuits, and the numerical aperture, or NA, has been increased. It is getting shallower. In order to cope with the shallow depth of focus, flattening of the device surface is required more than ever. As a method of flattening such a semiconductor surface, a chemical mechanical polishing (Chemical Mechanical Polishing or Chemical Mech
Anical Planarization (hereafter referred to as CMP) technology is considered a promising method.

[0004] CMP is performed using an apparatus as shown in FIG. In FIG. 5, 1 is a CMP apparatus, 10 is a polishing body, 3
Denotes a polishing object holding unit (polishing head), 4 denotes a polishing object (wafer), 5 denotes an abrasive supply unit, and 6 denotes an abrasive. The polishing body 10 is obtained by attaching a polishing pad 2 on a surface plate 7. As the polishing pad 2, a sheet-like thing made of foamed polyurethane or a thing made of non-foamed resin having a groove structure on its surface is used. The polishing head 3 is rotated (100) by a suitable means, and the polishing body 10 is rotated (101) by a suitable means. In this process, the surface to be polished of the wafer 4 is polished by the action of the polishing agent 6 and the polishing pad 2.

At present, the end point of the CMP polishing is determined by time management based on the polishing rate calculated by measuring the film thickness by an ellipsometer or the like after polishing several tens of dummy samples and passing through a cleaning process. Have been. However, the time management method is not always constant and stable due to various unstable factors such as changes in the surface condition of the polishing pad, changes in the polishing agent, and temperature changes. Is insufficient as a method of obtaining Furthermore, the time management method requires a polishing operation using dozens of dummy samples in order to obtain a polishing rate, and this polishing operation causes a cost increase, thereby stabilizing the semiconductor device manufacturing process. It is not preferable for reducing the production cost.

For this reason, in-situ measurement, in which the polishing amount and the remaining film thickness are measured while polishing to determine the polishing end point, has been actively studied, and among them, the film thickness measurement method using light is highly accurate. In this regard, it is attracting attention as a promising method.

The amount of polishing and the state of the wafer surface are optically measured.
-When performing situ measurement, it is common to observe the wafer surface through a measurement window provided in the polishing pad,
This technique is disclosed in US Pat. No. 5,433,651.

[0008]

When the polishing pad is provided with a window for measurement for the above-mentioned optical measurement, the material of the window is generally different from that of the polishing pad because the polishing pad is not transparent. It is necessary to arrange a transparent material. Since this material generally has different mechanical properties from the material of the polishing pad, there is a high risk of causing a difference in polishing rate, uneven polishing, and generation of scratches.

[0009] In addition, if the hole formed in the polishing pad is used as the measurement window as it is, water used for slurry or cleaning leaks from the window, so that a complicated mechanism for preventing the measurement system from being affected is required. However, there is a problem that the apparatus becomes complicated.

In addition, there is a problem in that the thickness of the polishing agent between the window and the object to be polished is not constant, and the measurement of the polishing film thickness or the polishing end point may be erroneously performed.

In addition, the measurement light used for measuring the polishing film thickness or the polishing end point is reflected on the front and back surfaces of the window on the side of the object to be polished, and the measurement may be erroneously performed in the measurement of the polishing film thickness or the polishing end point. There is a problem that there is.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. The present invention provides a polishing member, a polishing apparatus, an adjusting method, and a measuring method having a measuring window which does not cause instability in polishing and does not require a complicated mechanism. It is intended to provide.

Further, the present invention aims at reducing the cost of the polishing process and improving the process efficiency by accurately detecting the polishing state, thereby manufacturing a semiconductor device at a lower cost as compared with the conventional semiconductor device manufacturing method. It is an object of the present invention to provide a method for manufacturing a semiconductor device and a low-cost semiconductor device.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention first provides a polishing head and a polishing member for holding an object to be polished, wherein a polishing head is provided between the polishing member and the object to be polished. In a state in which an abrasive is interposed, by relatively moving the polishing member and the object to be polished, in the polishing member used in a polishing apparatus for polishing the object to be polished, the polishing member, the polishing member, A polishing member (Claim 1) is provided, which comprises a measurement window for transmitting measurement light for optically measuring the surface to be polished of the object to be polished.

A second feature is that the measurement window portion is constituted by a hole formed in the polishing member and a window plate fitted in the hole and transparent to at least measurement light. The polishing member according to the present invention (Claim 2) is provided.

Third, the distance between the outermost surface of the polishing member (the surface in contact with the object to be polished) and the uppermost surface of the window plate (hereinafter referred to as the upper surface) when no load is applied is determined by the polishing load. It is adjusted to be larger than the amount of compressive deformation of the polishing member at the time,
Further, in a state in which the polishing agent is filled in the space at the time of the polishing load, the transmittance for the measurement light is adjusted to 10% or more inclusive of the space and the transparent window. A polishing member according to claim 2 (claim 3) "is provided.

Fourthly, "a polishing head for holding an object to be polished and a polishing member, and the polishing member and the object to be polished are provided in a state where an abrasive is interposed between the polishing member and the object to be polished. By relatively moving the object, in the polishing member used in the polishing apparatus for polishing the object to be polished, the polishing member, to pass light for optically measuring the polished surface of the object to be polished A polishing member (claim 4), comprising a material transparent to at least the measurement light.

Fifth, the distance G between the outermost surface of the polishing member (the surface in contact with the object to be polished) and the uppermost surface of the window plate is 0 μm <G ≦ 400 μm. The polishing member according to claim 2 (claim 5) "is provided.

Sixth, a feature is that the distance G between the outermost surface of the polishing member (the surface in contact with the object to be polished) and the uppermost surface of the window plate is 10 μm ≦ G ≦ 200 μm. The polishing member according to claim 2 (claim 6) is provided.

Seventh, there is provided "a polishing member according to claim 2, wherein the transmittance of the window plate is 22% or more."

Eighth, there is provided "a polishing member according to any one of claims 2, 3, 5, 6, and 7, wherein the window plate is wedge-shaped (claim 8)."

Ninth, "a wedge-shaped transparent plate is further provided below the window plate.
The polishing member according to claim 9 is provided.

Tenthly, "a polishing member according to any one of claims 1, 2, 3, 5, 6, and 7, wherein irregularities are randomly formed on at least one surface of the measurement window portion. (Claim 10) "is provided.

Eleventh, the polishing member according to claim 10, wherein the reflectance of the surface of the measurement window portion on which the irregularities are formed is 2% or less. "
I will provide a.

A twelfth aspect is that the polishing member according to any one of claims 1 to 11, wherein at least the surface of the measurement window portion on the side of the object to be polished is hard-coated for reinforcement. Item 12) is provided.

Thirteenth, the polishing member according to any one of claims 1 to 12, wherein an anti-reflection film is formed on at least one surface of the measurement window. provide.

A fourteenth aspect of the present invention includes a polishing member according to any one of claims 1 to 13, a polishing head for holding the object to be polished, and an end point detecting mechanism. By relatively moving the polishing member and the object to be polished with an abrasive interposed therebetween, the object to be polished is polished, and measurement light is irradiated onto the surface to be polished through the polishing member during the polishing. Thus, the present invention provides a polishing apparatus (claim 14) in which the polishing state or the polishing film thickness can be optically measured.

Fifteenth, "the measurement light emitted from the end point detection mechanism passes through the polishing member, passes through the polishing agent between the polishing member and the object to be polished, and Reflected on the surface to be polished, passes again through the abrasive between the polishing member and the object to be polished, passes through the polishing member again, returns to the end point detection mechanism, and exits from the end point detection mechanism. The polishing apparatus according to claim 14, wherein a ratio of the intensity of the light returning to the end point detection mechanism to the intensity of the measurement light to be performed is 1% or more.

In the sixteenth aspect, the measurement light emitted from the end point detection mechanism passes through the polishing member, passes through the polishing agent between the polishing member and the object to be polished, and Reflected on the surface to be polished, passes again through the abrasive between the polishing member and the object to be polished, passes through the polishing member again, returns to the end point detection mechanism, and exits from the end point detection mechanism. The polishing apparatus according to claim 14, wherein the ratio of the intensity of the light returning to the end point detection mechanism to the intensity of the measurement light to be applied is 5% or more.

In a seventeenth aspect, there is provided "a polishing member according to any one of claims 10 and 11, comprising a polishing head for holding a polishing object and an end point detection mechanism, wherein a polishing member is provided between the polishing member and the polishing object. By relatively moving the polishing member and the object to be polished with an abrasive interposed therebetween, the object to be polished is polished, and measurement light is irradiated onto the surface to be polished through the polishing member during the polishing. In a polishing apparatus capable of optically measuring a polished state or a polished film thickness, unevenness formed on at least one surface of the window plate has a step larger than a wavelength of the measurement light. Polishing apparatus (claim 17). "

An eighteenth aspect of the present invention provides a polishing apparatus according to any one of claims 14 to 17, wherein the outermost surface of the polishing member (the surface in contact with the object to be polished) and the uppermost surface of the window plate. And adjusting the distance between the outermost surface of the polishing member and the uppermost surface of the window plate based on a signal measured by the end point detection mechanism. A characteristic adjustment method (Claim 18) is provided.

In the nineteenth aspect, in the method for measuring a polishing film thickness or a polishing end point by the polishing apparatus according to any one of claims 14 to 17, a signal measured by the end point detecting mechanism is measured and stored in advance. The signal measured by the end point detection mechanism is not used for the measurement of the polishing film thickness or the polishing end point when the signal measured by the end point detection mechanism and the signal measured in advance and stored are equal. And a measuring method (Claim 19).

Twentieth, "a semiconductor device manufacturing method comprising a step of flattening the surface of a semiconductor wafer by using the polishing apparatus according to any one of claims 14 to 17 (claim 20)" I will provide a.

A twenty-first aspect of the present invention provides a "semiconductor device manufactured by the semiconductor device manufacturing method according to the twentieth aspect."

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1, 3 and 8 are views for explaining a polishing pad and a polishing apparatus according to an embodiment of the present invention, respectively, but the present invention is not limited to this figure. Absent.

In FIG. 1, 2 is a polishing pad, and 14 is a transparent window plate. The transparent window plate 14 is fitted into the hole after the hole is formed in the polishing pad 2. Here, a space 13 is provided between the upper surface of the transparent window plate and the outermost surface which is the processing surface of the polishing pad. At the time of polishing, the polishing head 3 holding the wafer 4 is weighted on the polishing pad by a weighting mechanism (not shown) as shown in FIG. At this time, it is preferable that the interval 13 is constant and a dimension equal to or larger than the reference value is maintained.

As the polishing pad, a soft polishing pad made of urethane foam is not preferred.

The reason for this is that, in the case of a soft polishing pad made of urethane foam, which is commonly used, the amount of compressive deformation of the polishing pad due to the weight applied during polishing is large. Not only must
Since the amount of deflection against dynamic force such as irregular vibration of the retainer ring of the wafer or polishing head during weighting / polishing is large, the retainer of the surface to be polished of the wafer or the polishing head even when flexed to the maximum. This is because it is necessary to prevent the ring from contacting the upper surface of the window plate and being damaged. For this reason, it is necessary to make the gap 13 at the time of polishing load / compression relatively large, and the slurry enters the space created by the gap 13 and the measurement light must pass through the gap 13. There is a problem that the light transmittance for both the plate and the space 13 is reduced.

From the above viewpoint, a hard polishing pad having a small amount of compressive deformation is preferable as the polishing pad. Since the amount of compressive deformation with respect to the load of polishing is small, not only can the interval 13 between non-weighted and non-compressed be kept small, but also during the polishing load, irregular vibration of the retainer ring of the wafer or polishing head during polishing, etc. This is because the distance 13 during load / compression can be reduced because the amount of deflection against a dynamic force is small. If the interval 13 at the time of weighting / compression can be reduced, the transmittance for the measurement light increases, which is preferable for high-accuracy and stable measurement of the polished state. As the material of the polishing pad, epoxy resin, acrylic resin, ABC resin, vinyl chloride resin,
One or more materials selected from the group consisting of polycarbonate resin, polyester resin, and fluororesin are preferred.

As the window plate material, one or more materials selected from a group of materials such as transparent glass such as quartz glass, acrylic resin, vinyl chloride resin, polycarbonate and polyester are preferably used.

It is necessary to change the thickness of the window plate according to the thickness of the polishing pad. The light transmittance between the window plate 14 and the gap 13 for the measurement light depends on the gap 13 at the time of weighting / compression, the slurry concentration, and the thickness and material of the window board.

For highly accurate and stable measurement of the polished state, the transmittance of the window plate 14 is preferably 22% or more.

The transmittance of the measurement light to both the window plate 14 and the interval 13 is preferably 10% or more at the time of weighting / compression, but less than 10% when the light source intensity is high or the sensor sensitivity is high. However, measurement is possible.

The transmittance for the measurement light substantially depends on the concentration of the slurry entering the space 13 and the thickness of the slurry layer at the time of weighting / compression if the window plate material is selected from a transparent material.

Although the value of the interval 13 depends on the slurry concentration, it is preferably larger than 0 and not more than 400 μm with respect to a general slurry concentration.
μm is more preferred. The value of the interval 13 is generally large for a soft polishing pad made of urethane foam and small for a non-foamed hard polishing pad.

Further, although the interval 13 is determined so as not to come into contact with the retainer ring of the wafer or the polishing head in consideration of the load at the time of polishing, it is rarely caused by irregular vibration at the time of polishing. Since the window plate may suddenly come into contact with the wafer or the retainer ring of the polishing head and may be damaged, it is preferable to hard coat at least the surface of the window plate on the wafer side in order to prevent this. For example, in the case of an acrylic resin, a method of hard coating with a silicon-based organic resin is preferably performed.

The polishing pad described above can be preferably applied when the material itself of the polishing pad is opaque to the measurement light. It is a matter of course that this measurement window is not required for a polishing pad whose material is transparent to the measuring light.

The polishing pad of the present embodiment is the same as that of the polishing pad shown in FIG.
May be fixed to the surface plate 7, or may be used by being fixed to the surface plate 7 in a form poured into a surface plate such as an aluminum plate,
A material lined with one or more layers of other suitable different materials may be fixed to the surface plate 7 and used.

As described above, in the polishing apparatus shown in FIG. 3, the end point detectors 15 and 16 preferably measure the polishing state during polishing by the preferable functions of the polishing pad fixed to the surface plate 7 as described above. Can be.

Further, the intensity of the measuring light 17 emitted from the end point detecting device 15 which is an end point detecting mechanism, the light passing through the window plate 14, the abrasive between the window plate 14 and the object 4 to be polished, and the polishing The relationship between the intensity of light reflected on the surface to be polished of the object 4, passing again through the abrasive between the window plate 14 and the object 4, passing through the window plate 14 again, and returning to the end point detection device 15 is as follows. The ratio of the intensity of the light returning to the end point detection device 15 to the intensity of the measurement light 17 emitted from the end point detection device 15 is preferably 1% or more, and more preferably 5% or more.
Thereby, since the intensity of the light returning to the end point detecting device 15 does not decrease, highly accurate and stable measurement of the polished state by the end point detecting device 15 can be performed.

FIGS. 8A and 8B are modifications of the embodiment of the present invention shown in FIGS. FIG. 8A,
In (b), the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals.

In FIG. 8A, the window plate 30 has a wedge shape. The surface 30a on the wafer side of the window plate 30 is substantially parallel to the polished surface of the wafer 4, and the back surface (surface opposite to the wafer) 30b of the window plate 30 is inclined with respect to the polished surface of the wafer 4. The end point detection device 15 is installed so that the measurement light 17 is incident on the polished surface of the wafer 4 almost perpendicularly.

In FIG. 8A, the end point detecting device 15
30b of the window plate 30 of the measurement light 17 emitted from the
Since the light 17a reflected by the end point detecting device 15 does not return to the end point detecting device 15, highly accurate and stable measurement of the polished state by the end point detecting device 15 can be performed.

FIG. 8B is a modification of FIG. 8A, in which a wedge-shaped transparent plate 31 is further provided in the configuration of FIG. 8A. In FIG. 8B, the measuring light 17 is
Since the light passes through the wedge-shaped transparent plate 31 and the wedge-shaped window plate 30, the direction of light incident on the polished surface of the wafer is substantially perpendicular to the polished surface of the wafer, and the detection light emitted from the end point detection device 15. The direction 17 is also substantially perpendicular to the polished surface of the wafer. This eliminates the need to install the end point detection device 15 at an angle with respect to the polished surface of the wafer, so that the labor for installing the end point detection device 15 can be saved.

In FIG. 8B, the wedge-shaped transparent plate 31 is provided between the polishing pad 2 and the end point detecting device 15, but the wedge-shaped transparent plate 31 is provided with a hole in the polishing pad 2. Or may be installed in the end point detecting device 15.

Further, the measuring light is reflected on the back surface of the window plate of the polishing pad and / or on the surface on the wafer side of the polishing pad according to the embodiment of the present invention, so that the quantity of the measuring light is reduced or returned to the end point detecting device 15. In the measurement of the polishing film thickness or the polishing end point, the measurement may be erroneously performed. In order to prevent this, it is preferable to form an antireflection film on the front and / or back surface of the window plate on the wafer side. The antireflection film, for example, a single-layer antireflection film MgF ₂ or the like, or _{MgF 2, CeF 3, Al 2} O 3, SiO 2, Sb 2
A multilayer antireflection film or the like in which two or more films of O _{3 and the} like are stacked is used.

In the embodiment of the present invention, the measuring light is reflected on the back surface of the window plate of the polishing pad and / or the surface on the wafer side and returns to the end point detecting device 15 to measure the polishing film thickness or the polishing end point. , Measurement may be wrong. In order to prevent this, it is preferable to form irregularities randomly on the wafer side surface and / or back surface of the window plate. Thereby, the reflection of the measurement light on the surface having the unevenness is reduced. As a method of forming such irregularities, when the window plate is a resin, a method of forming irregularities by sandblasting, a method of forming irregularities by a grindstone or sandpaper, a stamper having irregularities formed when the resin is cured. In the case where the window plate is made of glass, there is a method of forming irregularities by sandblasting, a method of forming irregularities with a grindstone or sandpaper, a method of forming irregularities by chemical etching, and the like. .

In order to reduce the return light to the end point detecting device 15, it is preferable that the step of the unevenness is larger than the wavelength of the measurement light. Further, in order to reduce the return light to the end point detection device 15, the reflectance on the surface of the window plate having the unevenness is preferably 2% or less.

Next, an adjusting method according to the embodiment of the present invention will be described. The adjusting method according to the embodiment of the present invention includes adjusting the distance between the outermost surface of the polishing member 2 (the surface in contact with the object to be polished) and the surface of the window plate 14 on the outermost surface side of the polishing member 2 in the polishing apparatus. It is about the method. As the end point detecting device 15, an apparatus for measuring a polishing film thickness or a polishing end point from a reflection spectral characteristic (reflection spectral spectrum) is used. End point detection device 15
Is compared with a reference spectrum obtained by a simulation or the like in the signal processing device 16 of the end point detector, and the polishing film thickness or the polishing end point is measured.

If the distance between the outermost surface of the polishing member 2 of the window plate 14 and the outermost surface of the polishing member is too wide, the loss of light due to the abrasive existing in the space is too large, so that the end point detecting device 15 However, since only a weak signal can be obtained in the above method, the thickness of the polished film or the polishing end point cannot be measured well. On the other hand, if the gap is too narrow, a signal due to interference of the abrasive layer existing in the gap is added to the signal of the end point detection device 15, so that the polishing film thickness or the polishing end point cannot be measured well.

For this reason, in the adjusting method according to the embodiment of the present invention, while the signal measured by the end point detecting device 15 is observed, a signal capable of favorably measuring the polishing film thickness or the polishing end point is measured by the end point detecting device 15. The distance between the outermost surface of the polishing member 2 (the surface in contact with the object to be polished) and the uppermost surface of the window plate 14 is adjusted, that is, polishing is performed based on a signal measured by the end point detection device 15. Outermost surface of member 2 and window plate 14
Adjusting the distance from the outermost surface.

Next, the measuring method according to the embodiment of the present invention will be described. The measuring method according to the embodiment of the present invention relates to a method for measuring a polishing film thickness or a polishing end point in the polishing apparatus. As the end point detecting device 15, an apparatus for measuring a polishing film thickness or a polishing end point from a reflection spectral characteristic (reflection spectral spectrum) is used.

During polishing, the thickness of the polishing agent between the window and the object to be polished is not constant, and an inappropriate signal may be obtained in measuring the polishing film thickness or the polishing end point. The inappropriate signal is, for example, a weak signal when the loss due to the abrasive is too large, as described in the adjustment method of the embodiment of the present invention,
And a signal to which a signal due to interference of a layer of abrasive existing at a distance between the outermost surface of the polishing member 2 of the window plate 14 and the outermost surface of the polishing member is added.

Therefore, according to the measuring method of the embodiment of the present invention, an inappropriate signal or the like obtained at the time of adjustment of the adjusting method of the embodiment of the present invention is stored in a storage device (not shown) as a previously measured signal. The end point detection device 15 is stored during polishing.
Comparing the signal measured in step (b) with the signal stored in the storage device. Further, the measuring method according to the embodiment of the present invention, when the signal measured by the end point detection device 15 and the signal stored in the storage device are equal, the signal measured by the end point detection device 15 is a polishing film thickness or polishing end point There is a step not used for detection. Thus, even when the thickness of the polishing agent between the window and the object to be polished is not constant and becomes unstable, the measurement of the polishing film thickness or the polishing end point does not result in an erroneous measurement.

FIG. 7 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 of 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 polishing apparatus 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.

Step S after the CMP step or the oxidation step
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 method of manufacturing a semiconductor device according to the present invention, since the polishing apparatus according to the present invention is used in the CMP process, the measurement accuracy of the polishing end point or the measurement accuracy of the film thickness in the CMP process is improved. And 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.

The polishing apparatus according to the present invention may be used in a CMP step of a semiconductor device manufacturing process other than the above-described semiconductor device manufacturing process.

The 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.

[0073]

[Embodiment 1] FIG. 2 is a sectional view showing a polishing pad according to Embodiment 1.

The epoxy base material Epicoat 828 and Epicoat 871 (both manufactured by Yuka Shell Epoxy Co., Ltd.) and the curing agent diaminodiphenylmethane were mixed at a weight ratio of 2.6: 3.9: 1 and stirred to form a hole as an observation window. Φ of the type
Pour this on an 800mm aluminum plate and at 150 ° C
Cured for 8 hours and molded.

Next, a spiral V-groove (V angle 60 °) having a pitch of 0.5 mm and a depth of 0.3 mm was formed on the surface of the epoxy resin by cutting.
Then, a grid-shaped square groove having a pitch of 15 mm, a width of 2 mm, and a depth of 0.5 mm was formed. FIG. 6 shows a cross section of a V groove (V angle 60 °) of this polishing pad.

The thickness of the resin part of this polishing pad was 2 mm, and the amount of compressive deformation was 10 kgf / cm ² (9.8 × 10 ⁵ Pa).
Was 2 μm with respect to the load.

An acrylic material was selected as a material for the window plate 14, a hard coating solution in which colloidal silica was dispersed in a known co-hydrolyzed product of epoxysilane was applied, and then cured by heating to form a hard coat having a thickness of about 1 μm. did. As shown in FIG. 2, the hard coat side of the window plate 14 is directed to the uppermost layer side of the polishing pad, and the interval 13 is 100 μm at the time of load and compression.
And fixed in the hole of the formed polishing pad. Slurry (Cabot SS25 diluted 2 times) at intervals of 13
The transmittance of both the window plate 14 and the interval 13 to the measurement light when the sample was filled was 89%. [Embodiment 2] FIG.
Is a polishing apparatus of the present embodiment. In FIG. 3, 10 is a polishing body, 3
Is a polishing head, 4 is a wafer, 5 is an abrasive supply section, and 6 is an abrasive. The polishing body 10 has a polishing pad 2 on a surface plate 7.
And the polishing pad 2 used in the first embodiment is used. At a position corresponding to the window plate 14 of the surface plate 7, a through hole for passing the measurement light is formed. Reference numeral 15 denotes a film thickness measuring device, and 16 denotes a signal processing device.

The polishing apparatus operates as follows. The polishing head 3 holding the wafer 4 is a weighting mechanism (not shown)
The polishing pad 2 is pressurized to perform a rotating motion (not shown) and a swinging motion (not shown) by appropriate means, and the polishing body 10 is rotated (not shown) by appropriate means. In this process, the surface to be polished of the wafer 4 is polished by the action of the polishing agent 6 and the polishing pad 2. During polishing, a measuring light 17 is emitted from a film thickness measuring device provided below the platen 7.
Then, the polished surface of the wafer is irradiated through the hole of the polishing pad and the window plate of the polishing pad, and the reflected signal light is again received by the photodetector of the film thickness measuring device 15 through the same optical path. It is processed by the signal processing device 16 and the polishing state is measured.

A thermal oxide film is formed on the polishing head of the above polishing apparatus.
A 6-inch silicon wafer having a thickness of 1 μm was held and polished under the following conditions.

Polishing head rotation speed: 50 rpm Surface plate rotation speed: 20 rpm Load: 460 g / cm ² (4.5 × 10 ⁴ Pa) Swing width: 30 mm Swing speed: 15 strokes / min Polishing time: 3 minutes Slurry used SS25 is diluted twice. Slurry flow rate: 200 ml / min. During polishing, the remaining film thickness is optically measured in-situ through an observation window plate as shown in FIG. As a result of repeated measurement, the stability of the measurement was confirmed.

In addition, there was no adverse effect of uneven polishing and generation of scratches by the measurement window.

[0082]

As described above, according to the present invention, the amount of polishing and the state of the surface of the object to be polished can be stably and optically in-situ without causing non-uniform polishing and scratches. It is possible to provide a simple polishing member and a polishing apparatus that can measure with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a polishing pad having a measurement window according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a polishing pad having a measurement window according to the first embodiment.

FIG. 3 is a conceptual diagram of a polishing apparatus including a polishing pad according to the first embodiment and an end point detection device (a film thickness measuring device and a signal processing device).

FIG. 4 is an example of data obtained by in-situ measurement of a change in remaining film thickness due to polishing obtained in the present invention.

FIG. 5 is a conceptual diagram of a conventional CMP apparatus.

FIG. 6 is a sectional view of a groove shape of the polishing pad of the first embodiment.

FIG. 7 is a flowchart showing a semiconductor device manufacturing process.

FIG. 8 is a schematic cross-sectional view of a polishing pad provided with a measurement window according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CMP apparatus 2 Polishing member (polishing pad) 3 Polishing object holding part (polishing head) 4 Polishing target (wafer) 5 Polishing agent supply part 6 Polishing agent (slurry) 7 Surface plate 10 Polishing body 11 Surface plate (aluminum plate) 12) Polishing pad 13 Spacing between the outermost surface of the polishing pad and the upper surface of the window plate 14 Transparent window plate 15 Film thickness measuring device ... End point detecting device 16 Signal processing device ... End point detecting device 17 Measurement light 25 Outermost surface of polishing pad 26 Groove of polishing pad 30 Wedge-shaped window material 31 Wedge-shaped transparent plate

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akira Miyaji 3-2-3 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon Corporation (reference) 2F065 AA30 BB03 BB16 CC19 HH13 JJ01 JJ09 LL00 LL49 PP13 3C058 AA09 AA12 AC02 AC04 BA01 BA07 BA09 CB10 DA12 DA17

Claims (21)

[Claims] A polishing head for holding an object to be polished; and a polishing member, wherein the polishing member and the object to be polished are interposed in a state where an abrasive is interposed between the polishing member and the object to be polished. By relative movement, in the polishing member used in the polishing apparatus for polishing the polishing object, the polishing member, for passing measurement light for optically measuring the surface to be polished of the polishing object. A polishing member comprising a measurement window. 2. The apparatus according to claim 1, wherein said measurement window comprises a hole formed in said polishing member and a window plate which is fitted in said hole and is at least transparent to measurement light. Polishing member. 3. The outermost surface of the polishing member when no load is applied.
The distance between the surface (the surface in contact with the object to be polished) and the surface on the outermost surface side (hereinafter referred to as the upper surface) of the window plate is adjusted to be larger than the amount of compressive deformation of the polishing member at the time of a polishing load. The transmittance of the measurement light is adjusted to 10% or more in total with the gap and the transparent window in a state where the polishing agent is filled in the gap at the time of load. 3. The polishing member according to 2. 4. A polishing head for holding an object to be polished and a polishing member, and the polishing member and the object to be polished are interposed in a state where an abrasive is interposed between the polishing member and the object to be polished. By relative movement, in the polishing member used in the polishing apparatus for polishing the polishing object, the polishing member, at least a measurement for transmitting light for optically measuring the polishing surface of the polishing object A polishing member comprising a material transparent to light. 5. A distance G between an outermost surface of the polishing member (a surface in contact with an object to be polished) and a surface of the window plate on the uppermost surface side is defined as:
3. The structure of claim 2, wherein 0 .mu.m <G.ltoreq.400 .mu.m.
The polishing member according to the above. 6. A distance G between an outermost surface of the polishing member (a surface in contact with an object to be polished) and a surface of the window plate on the outermost surface side is defined as:
3. The polishing member according to claim 2, wherein 10 μm ≦ G ≦ 200 μm. 7. The polishing member according to claim 2, wherein said window plate has a transmittance of 22% or more. 8. The polishing member according to claim 2, wherein said window plate has a wedge shape. 9. The polishing member according to claim 8, wherein a wedge-shaped transparent plate is further provided below the window plate. 10. The method according to claim 1, wherein irregularities are randomly formed on at least one surface of said measurement window.
The polishing member according to any one of 2, 3, 5, 6, and 7. 11. The polishing member according to claim 10, wherein the reflectance of the surface of the measurement window portion on which the irregularities are formed is 2% or less. 12. The polishing member according to claim 1, wherein at least a surface of the measurement window on the side of the object to be polished is hard-coated for reinforcement. 13. An antireflection film is formed on at least one surface of the measurement window.
The polishing member according to claim 1. 14. A polishing member comprising a polishing member according to claim 1, a polishing head for holding a polishing object, and an end point detecting mechanism, wherein an abrasive is provided between the polishing member and the polishing object. In the interposed state, by relatively moving the polishing member and the object to be polished, the object to be polished is polished,
A polishing apparatus capable of optically measuring a polished state or a polished film thickness by irradiating a measurement light to the surface to be polished through the polishing member during the polishing. 15. The measurement light emitted from the end point detection mechanism passes through the polishing member, passes through the polishing agent between the polishing member and the object to be polished, and passes through the polishing object on the object to be polished. The measurement reflected by the polishing surface, passes through the abrasive again between the polishing member and the object to be polished, passes through the polishing member again, returns to the end point detection mechanism, and exits from the end point detection mechanism. The polishing apparatus according to claim 14, wherein a ratio of a light intensity returning to the end point detection mechanism to a light intensity is 1% or more. 16. The measurement light emitted from the end point detection mechanism passes through the polishing member, passes through the polishing agent between the polishing member and the object to be polished, and is applied to the surface of the object to be polished. The measurement reflected by the polishing surface, passes through the abrasive again between the polishing member and the object to be polished, passes through the polishing member again, returns to the end point detection mechanism, and exits from the end point detection mechanism. The polishing apparatus according to claim 14, wherein a ratio of an intensity of light returning to the end point detection mechanism to an intensity of light is 5% or more. 17. A polishing apparatus comprising: the polishing member according to claim 10; a polishing head for holding a polishing object; and an end point detecting mechanism, wherein an abrasive is provided between the polishing member and the polishing object. In the interposed state, the polishing member and the object to be polished are relatively moved to polish the object to be polished, and the measurement light is irradiated onto the surface to be polished through the polishing member during the polishing. A polishing apparatus capable of measuring a polished state or a polished film thickness, wherein the unevenness formed on at least one surface of the window plate has a step larger than the wavelength of the measurement light. apparatus. 18. A distance between an outermost surface (a surface in contact with an object to be polished) of the polishing member and a surface on the outermost surface side of the window plate in the polishing apparatus according to any one of claims 14 to 17. Adjusting the distance between the outermost surface of the polishing member and the uppermost surface of the window plate based on a signal measured by the end point detection mechanism. Adjustment method. 19. A method for measuring a polishing film thickness or a polishing end point by a polishing apparatus according to any one of claims 14 to 17, wherein a signal measured by said end point detecting mechanism and a signal measured and stored in advance. Comparing the signal measured by the end point detection mechanism and the signal measured in advance by the end point detection mechanism when the signal stored in advance is equal to the step of not using the signal measured by the end point detection mechanism for the measurement of the polishing film thickness or the polishing end point. A measuring method characterized by having: 20. A method of manufacturing a semiconductor device, comprising the step of flattening the surface of a semiconductor wafer using the polishing apparatus according to claim 14. 21. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 20.