JP2001198813A - Polishing device and its polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly accurate and highly reliable polishing device and a polishing method by removing a disturbance component produced when measuring friction. SOLUTION: Power supplies 17, 18 for driving are connected to motors 12, 15 to rotate a surface plate 10 and a holding member 14, and ammeters 19, 20 to detect currents passing through the motors 12, 15 are connected to the power supply wires. The currents detected by the ammeters 19, 20 are sent to control devices 23, 24 through means of measurement 21, 22. The means of measurement 21, 22 have a feature that they act as filters to pass only a variable component of 10 Hz or less among variable components of the current detected by the ammeters 19, 20 relative to the time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and a polishing method, and more particularly, to a polishing apparatus and a polishing method used for flattening an interlayer insulating film and a metal wiring layer of a semiconductor device.

[0002]

2. Description of the Related Art In recent years, with the increase in the degree of integration of semiconductor devices, multilayer wiring has been developed. In order to construct such an advanced wiring structure, it is important to establish a so-called flattening technique for flattening an uneven surface shape in one process. A widely used planarization technique is chemical mechanical polishing (Chemical Mechanical Polishing:
CMP) method.

In general, a CMP apparatus comprises a surface plate on which a polishing pad for polishing a semiconductor wafer is laid, a holding member provided to face the polishing pad, and a holding member for holding the semiconductor wafer, and a polishing pad. The apparatus includes a slurry supply nozzle for supplying a slurry as a chemical solution for polishing, a motor for rotating a platen and a holding member in a horizontal plane, and a power supply for driving the motor.

Next, a polishing method using a CMP apparatus having such a configuration will be described. First, the semiconductor wafer is fixed to the holding member by vacuum suction with the surface to be polished facing down. Then, the semiconductor wafer is brought into contact with and pressed against the upper surface of the polishing pad on the surface plate by applying a constant pressure to the holding member. Next, the platen and the holding member are rotated while supplying the slurry onto the polishing pad. Thereafter, after the predetermined polishing time has elapsed, the holding member is raised and the semiconductor wafer is taken out, and the polished surface of the semiconductor wafer is in a flattened state.

In the polishing method using the CMP apparatus as described above, for example, in the case of flattening an interlayer insulating film, a conventional BPSG (Boron) having a high step coverage can be applied to the material of the interlayer insulating film.
The flatness is remarkably superior to the flattening technology by the reflow method using Phosphorous Silicate Glass). Further, it has many advantages such as being able to be used not only at the chip level but also for flattening a large area at the wafer level.

In the polishing by the CMP apparatus, the polishing rate largely depends on the surface condition of the polishing pad due to the configuration of the apparatus. The polishing pad deteriorates due to abrasion of the surface thereof as the polishing is repeated, but the amount of the deterioration is not uniform. Therefore, before polishing a semiconductor wafer to be planarized, a test semiconductor wafer (test pie
It is necessary to monitor the surface condition of the polishing pad by measuring the relationship between the polishing time and the polishing amount using ce). In addition, when the semiconductor wafer is flattened, it is necessary to monitor the surface state of the semiconductor wafer in order to detect the polishing end point.

Conventionally, the surface condition of the polishing pad and the semiconductor wafer is generally monitored by detecting a change in friction between the polishing pad and the surface of the semiconductor wafer during polishing. As one of means for measuring the change in friction, there is a method utilizing a change in current of a motor for driving a platen on which a polishing pad is laid or a holding member holding a semiconductor wafer. However, the change in the current value includes many disturbance components such as a current variation caused by the rotational movement of the base and the holding member, and electric noise of peripheral devices. Therefore, it is very difficult to read a minute change in the surface state of the polishing pad and the semiconductor wafer from the change in the current value, and there has been a problem that the polishing cannot be performed with high accuracy.

[0008]

As described above, the conventional CMP apparatus detects a change in friction between the polishing pad and the surface of the semiconductor wafer during polishing in order to monitor the surface condition of the polishing pad and the semiconductor wafer. Was. As means for measuring the change in friction, a change in the current of a motor that drives a surface plate or a holding member has been used. However, since the change in the current value includes many disturbance components such as variation and electric noise, it is very difficult to read a minute change in the surface state of the polishing pad and the semiconductor wafer from the change in the current value. However, there is a problem that polishing cannot be performed with high accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a highly accurate and highly reliable polishing apparatus and method by removing disturbance components generated when measuring friction. Is to do.

[0010]

According to a first aspect of the present invention, there is provided a polishing apparatus for polishing a semiconductor substrate on which a layer to be polished is formed, a platen on which the polishing unit is laid, Holding means for holding the semiconductor substrate, supporting means for supporting the holding means, and abutting and pressing the polished surface of the semiconductor substrate held by the holding means against the polishing means,
Between the driving means for rotating the surface plate and the holding means in a horizontal plane, the polishing means on the surface plate driven by the driving means, and the surface to be polished of the semiconductor substrate held by the holding means; And a measuring means for measuring only a low-frequency change component among time-dependent change components of the measured value indicating the friction detected by the friction detection means. And

[0011] As described in claim 2, in the polishing apparatus according to claim 1, the driving means is an electric motor,
The friction detecting means detects the friction by detecting at least one of a current flowing through the electric motor driving the surface plate and the holding means.

According to a third aspect of the present invention, in the polishing apparatus according to the first or second aspect, the measuring means has at least one of a noise filter and an arithmetic processing unit formed of an electric circuit. It is characterized by.

According to a fourth aspect of the present invention, in the polishing apparatus according to any one of the first to third aspects, the measuring means changes the measured value indicating the friction detected by the friction detecting means with respect to time. It is characterized in that only the change component of 10 Hz or less among the components is measured.

According to a fifth aspect of the present invention, there is provided a polishing method comprising the steps of: polishing a surface to be polished formed on a semiconductor substrate; polishing means for polishing the surface to be polished; Detecting friction between the polished surface;
And measuring only a low-frequency change component of the change component of the measured value indicating the detected friction with respect to time.

According to a sixth aspect of the present invention, in the polishing method according to the fifth aspect, after the step of measuring only a low-frequency change component among time-dependent change components of the measured value indicating the detected friction. And a step of calculating an optimal polishing condition based on a measurement result of friction having only the low-frequency change component.

According to a seventh aspect of the present invention, in the polishing method according to the sixth aspect, the semiconductor substrate is a test semiconductor substrate for detecting a state of the polishing means,
After the step of calculating the polishing conditions, the semiconductor substrate on which the semiconductor device is formed is polished based on the calculated polishing conditions.

According to an eighth aspect of the present invention, in the polishing method according to any one of the fifth to seventh aspects, only the low-frequency change component of the change component of the measured value indicating the detected friction with respect to time. Is characterized by measuring only an arbitrary frequency component of 10 Hz or less from a change component of the measured value indicating friction with respect to time.

According to a ninth aspect of the present invention, in the polishing method according to any one of the fifth to eighth aspects, the polishing conditions include a polishing time, a pressure applied to the support member during polishing, a number of rotations of a polishing means, It is at least one of the number of rotations of the holding member and the flow rate of the polishing liquid supplied to the polishing means.

According to the polishing apparatus of the first aspect, only a predetermined change component of the change component of the measurement value indicating the friction detected by the friction detection unit with respect to time is measured by the measurement unit. That is, it is possible to extremely reduce noise included in components other than the predetermined change component of the friction detected by the friction detecting unit. Therefore, the measurement result of the friction can be made clear, so that the information of the polishing state can be accurately grasped, so that precise polishing can be performed, and the accuracy and reliability of the polishing apparatus can be improved.

As described in the second aspect, the detection of friction may be performed by detecting a current flowing through an electric motor for driving the surface plate or the support means.

As described in claim 3, the measuring means for cutting components other than the predetermined change component of friction can be constituted by a noise filter constituted by an electric circuit or arithmetic processing.

According to a fourth aspect of the present invention, the measuring means measures only a desired change component of 10 Hz or less or a desired change component of 10 Hz or less among the change components of the measured value indicating friction with respect to time, thereby greatly reducing noise. Since sufficient polishing information can be obtained, the accuracy and reliability of the polishing apparatus can be improved.

According to the polishing method of the present invention, after detecting the friction between the polishing means and the semiconductor substrate, only a predetermined change component of the change component of the measured value indicating the friction with respect to time is measured. By doing so, noise included in components other than the predetermined change component is extremely reduced. Therefore, the measurement result of the friction can be made clear, so that the information of the polishing state can be accurately grasped, so that precise polishing can be performed, and the accuracy and reliability of the polishing method can be improved.

According to a sixth aspect of the present invention, first, the test piece is polished or the product wafer is polished, and the friction at this time is measured to grasp the state of the polishing means and calculate the optimum polishing conditions. Thus, the accuracy and reliability of the polishing method can be improved, and the production yield of the semiconductor device can be improved.

As described in claim 8, the measuring means measures only the desired change component of 10 Hz or less or the desired change component of 10 Hz or less among the change components of the measured value indicating the friction with respect to time, thereby greatly reducing the noise. Since sufficient polishing information can be obtained, the accuracy and reliability of the polishing method can be improved.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. For this explanation,
Common parts are denoted by common reference symbols.

A polishing apparatus and a polishing method according to a first embodiment of the present invention will be described with reference to FIG. Figure 1 is a CM
It is a schematic perspective view of P apparatus.

As shown in the figure, a polishing pad (polishing) for polishing the semiconductor wafer 1 is provided on a platen 10 having a radius sufficiently larger than the diameter of the semiconductor wafer 1 and rotatable in a horizontal plane. Means 11 are laid uniformly over the entire surface of the surface plate 10. A motor (driving means) 12 for rotating the surface plate 10 is provided on the surface plate 10 via a rotation shaft 13. A holding member (holding means) 14 for holding the semiconductor wafer 1 is provided on the upper surface of the polishing pad 11 so as to face the polishing pad 11 so as to be rotatable in a horizontal plane. A motor (driving means) 15 for rotating the holding member 14 is provided on the holding member 14 via a rotating shaft (supporting means) 16. The power supplies 17 and 18 for driving are connected to the motors 12 and 15 via power supply lines, respectively, and an ammeter (friction detecting means) for detecting a current flowing through the motors 12 and 15 is connected to the power supply lines. 19,
20 are connected. The currents detected by these ammeters 19 and 20 are passed through filters (measuring means) 21 and 22.
It is sent to the control devices 23 and 24 via each. The filters 21 and 22 detect 10H of the change components of the current detected by the ammeters 19 and 20 with respect to time.
It is an active filter or the like that passes only a change component equal to or smaller than z, and is, for example, a Butterworth-type low-pass filter. Further, a slurry supply nozzle 26 for supplying the slurry 25 is provided on the polishing pad 11.

Next, with respect to the polishing method using the CMP apparatus having the above configuration, a test semiconductor wafer (test p.
The polishing will be described with reference to FIGS. FIGS. 2A to 2C are cross-sectional views sequentially showing a polishing process of a test semiconductor wafer.
The figure is before polishing, the figure (b) is during polishing, and the figure (c) is after polishing. Here, as a test semiconductor wafer, a silicon substrate 30 in which a silicon oxide film 31 is formed so as to cover an Al wiring layer 32 is taken as an example. As shown in FIG. 2A, the surface of the silicon oxide film 31 on the silicon substrate 30 is not flat due to the influence of the Al
1 'exists.

The above semiconductor wafer is first placed on the holding member 14.
Surface to be polished (silicon oxide film 31) by vacuum suction
Hold side down. The holding member 14 holding the semiconductor wafer is transferred onto the platen 10 by a transfer device (not shown) together with the rotating shaft 16 and the motor 15. Then, the holding member 14 is lowered, and the platen 10 and the holding member 14 are rotated by the motors 12 and 15 in a state where the surface to be polished of the semiconductor wafer 1 is in contact with the polishing pad 11, and
A load is applied to the holding member 14. As a result, a mechanical pressing force acts between the surface to be polished of the semiconductor wafer and the polishing pad 11.

With this operation, the polished surface of the test semiconductor wafer held by the holding member 14 is rubbed while being pressed against the polishing pad 11 on the surface plate 10, so that the polished surface of the semiconductor wafer is Polished by the polishing pad 11.
During this polishing operation, the slurry 25 is supplied from the slurry supply nozzle 26 onto the polishing pad 11. Thus, the polishing effect is enhanced by the slurry 25 in addition to the mechanical polishing, and the chemical mechanical polishing (CMP) is performed. FIG. 2 shows a sectional view of the semiconductor wafer being polished.
(B).

During polishing, the ammeters 19 and 20 constantly measure the current flowing through the motors 12 and 15, and the measurement data is sent to the control devices 23 and 24 via the filters 21 and 22, respectively. The filters 21 and 22 pass only the fluctuation components of 10 Hz or less from the measurement data obtained by the ammeters 19 and 20 from the fluctuation components with respect to time, and cut the higher frequency components. Then, the control devices 23 and 24 monitor the measurement data including only the variation component of 10 Hz or less among the variation components with respect to time, and recognize this current as friction generated between the semiconductor wafer and the polishing pad 11. And this change in friction causes CM
Know the progress of P.

FIG. 3A shows an actual measurement result of a current value flowing through the motor 12 with respect to a polishing time when the test semiconductor wafer shown in FIG. 2A is polished. FIG. 6B is a measurement result obtained by averaging the measurement results of FIG.

As shown in FIGS. 3A and 3B, the current increases when the polishing time exceeds 50 seconds. In other words, this indicates that the friction between the polishing pad 11 and the semiconductor wafer has increased from this vicinity, and it can be seen that the polishing of the protrusion 31 ′ of the SiO ₂ film 31 has started.
The current value continues to increase up to about 120 seconds thereafter. The period from 60 to 120 seconds corresponds to the state shown in FIG.

After 120 seconds, the current value is kept almost constant. This indicates that the friction between the polishing pad 11 and the semiconductor wafer is constant. That is, the entire surface of the interlayer insulating film 31 of the semiconductor wafer is in contact with the polishing pad 11, and corresponds to the state shown in FIG. 2C. You can see that there is.

Thus, the polishing of the test semiconductor wafer is completed, and the semiconductor wafer is removed from the holding member 14. From the change in the amount of current monitored during polishing of the test semiconductor wafer, it is possible to determine how much the polishing pad 11 has been consumed. Therefore, the control devices 23 and 24
Calculates the next polishing condition according to the degree of consumption of the polishing pad 11 from the data of the current. The polishing conditions include, for example, a polishing time, a pressure applied to the holding member 14 at the time of polishing, rotation speeds of the holding member and the platen, a slurry supply amount, and the like.

As described above, the filters 21 and 22 for passing only the change component of 10 Hz or less among the change components of the current with respect to time are provided in order to reduce noise included in the current value. This is clearly different from the conventional method in which all frequency components of the current are measured. CMP without conventional filter for reference
FIGS. 4A and 4B show the measurement results obtained by the apparatus. FIG.
FIG. 2A is an actual measurement result of a current value flowing through the motor 12 with respect to a polishing time when the test semiconductor wafer shown in FIG. 2A is polished, and FIG. Is a measurement result obtained by averaging the measurement results every 6 seconds.

As shown in FIG. 4, in the conventional method, the noise is overwhelmingly large, and it is difficult to read the start and end points of the CMP as compared with the measurement result according to the present embodiment shown in FIG. It can be seen that there is a great difference in the monitoring accuracy of the progress of the CMP between them. In particular, Si
When polishing O ₂ , the amount of change in current before and after polishing is only 0.5 A, so that superposition of noise has a great effect. Therefore, providing a filter has a great effect.

The filters 21 and 22 have a frequency of 10 Hz.
Is removed, but the lower limit of the frequency to be removed is not limited to this value. FIGS. 5A and 5B and FIGS. 6A and 6B show that the current flowing through the motors 12 and 15 is represented by FT (Fourier Transmissio).
n) shows a spectrum decomposed into frequency components. FIG. 5A shows a frequency spectrum in the range of 0 to 1 MHz, and FIG. 5B shows a case in which the load applied to the holding member is three times that in FIG. FIGS. 6A and 6B respectively show FIGS.
It is an enlarged view of the area of 0-100 Hz in (a) and (b).

As shown in the figure, it can be seen that large noise does not exist in a specific frequency region, but the noise is uniformly superimposed over the entire frequency region of 0 to 1 MHz. For this reason, only the frequency region necessary for obtaining the polishing information of the CMP may be extracted, and all other frequency components may be removed. Usually, in order to know the state of the surface to be polished by CMP, a change component of 10 Hz or more is not required. Therefore, in the present embodiment, the frequency component exceeding 10 Hz is removed. However, it is not necessary to strictly set the value of 10 Hz as the upper limit of the pass frequency, and it should be appropriately changed according to the required monitor accuracy. However, normal CMP
, Optimal polishing information can be obtained from components of 10 Hz or less, specifically, less than 1 Hz.

As described above, by improving the monitoring accuracy of the progress of the CMP, the state of the polishing pad of the CMP apparatus can be accurately grasped. That is, the same test semiconductor wafer is polished every time or periodically before polishing with a CMP apparatus, and the degree of consumption of the polishing pad 11 can be accurately determined from the relationship between the polishing amount and the polishing time. I can do it. Therefore, maintenance and management of the CMP apparatus can be facilitated, so that the reliability and performance of the CMP apparatus can be improved.

The filters 21 and 22 are not limited to the active filters, but may be passive filters composed of an inductance and a capacitor. In addition to these electrical filters, noise may be removed by arithmetic processing such as digital data smoothing processing or frequency analysis by FFT (Fast Fourier Transmission).

Next, a polishing apparatus and a polishing method according to a second embodiment of the present invention will be described with reference to FIGS. 7A to 7D, taking polishing of a multilayer metal wiring layer of a semiconductor device as an example. I do. 7A to 7D are cross-sectional views sequentially illustrating a polishing process of a semiconductor device to be polished.

As shown in FIG. 7A, a semiconductor device taken as an example includes a patterned barrier metal layer 42 and a W (Tungsten) film on an interlayer insulating film 41 formed on a semiconductor substrate (not shown). A metal wiring layer 43 is formed. Then, polishing is performed by the polishing apparatus shown in FIG. Note that the polishing method is exactly the same as the process described in the first embodiment, and a description thereof will be omitted.

FIG. 8 shows the results of measuring the current flowing through the motors 12 and 15 with the ammeters 19 and 20 when the semiconductor device having the structure shown in FIG. In the figure, the waveform observed from 0 to 10 seconds at the beginning of polishing is
This is the noise before the CMP is stabilized. First, the current observed between 30 and 60 seconds is constant at about 5A. This region is in a state where the W film 43 on which the pattern is formed is being polished. Next, 60 seconds after the start of polishing, the current value rises to about 7A. This is in a state where the entire surface of the W film 43 exposed on the surface of the semiconductor device is in contact with the polishing pad 11, ie, the W film 4
Reference numeral 3 denotes a substantially flattened state, which corresponds to the structure in FIG. Thereafter, in a region where the current value decreases from 7 A, the W film 43 and the barrier metal layer 42 are being polished. And 5.5 observed between 70 and 90 seconds
In the region almost constant at A, the exposed barrier metal layer 4
2 and the W film 43 are in contact with the polishing pad 11, and this corresponds to the structure of FIG. After 90 seconds, the current value drops again, and the current value after 120 seconds is constant at about 4.7 A. This region corresponds to the structure of FIG. 7D, and includes an interlayer insulating film 41, a barrier metal layer 42, and a W film 4.
3 is being polished.

As described above, the motors 12, 15
The polishing information can be obtained quite accurately from the current flowing through the polishing pad. This is because the noise superimposed on the current is removed by the filters 21 and 22. For reference, FIG. 9 shows a measurement result of a current by a conventional polishing apparatus having no measuring means 21 and 22. As shown in the figure, a state in which the current has a peak 60 seconds after the start of polishing can be observed, but in other cases, sufficient information cannot be obtained due to too much noise.

The most important factor in the CMP apparatus is to control the flatness of the wafer and at the same time how to accurately detect the end point of polishing. It is also an important point in obtaining characteristics and reliability.

According to the polishing apparatus and the polishing method described in the first and second embodiments, by providing the filters 21 and 22, the data measured by the ammeters 19 and 20 can be used to determine the change components with respect to time. Only fluctuating components of 10 Hz or less are passed, and higher frequency components are cut off. Therefore, the noise of the measurement data sent to the control devices 23 and 24 is significantly reduced. Therefore, polishing information by CMP can be obtained with high accuracy, and the state of the polishing pad and the progress of polishing can be grasped with high accuracy. Therefore, the accuracy and reliability of the CMP apparatus and the polishing method can be improved.

[0049]

As described above, according to the present invention, a highly accurate and highly reliable polishing apparatus and method can be provided by removing disturbance components generated when measuring friction.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a CMP apparatus for explaining a polishing apparatus and a polishing method according to a first embodiment of the present invention.

FIGS. 2A and 2B are views for explaining a polishing apparatus and a polishing method according to a first embodiment of the present invention, and show a polishing process of a semiconductor wafer for a test; FIG. The figure in () is a view during polishing and the figure (c) is a sectional view after polishing.

3A and 3B are views for explaining a polishing apparatus and a polishing method according to the first embodiment of the present invention. FIG. 3A shows a time change of a current flowing through a motor during polishing.
(B) The figure shows the time averaged data for 6 seconds in (a).

4A and 4B are views for explaining a conventional polishing apparatus and a conventional polishing method. FIG. 4A shows a time change of a current flowing through a motor during polishing, and FIG. Time averaged data for seconds.

5A and 5B are views for explaining a polishing apparatus and a polishing method according to the first embodiment of the present invention. FIG. 5A shows a frequency spectrum of a current flowing through a motor during polishing, and FIG. The figure shows the frequency spectrum of the current flowing through the motor under different measurement conditions from the figure (a).

FIGS. 6A and 6B are views for explaining a polishing apparatus and a polishing method according to the first embodiment of the present invention, wherein FIGS.
FIG. 5B is an enlarged view of a frequency range of 0 to 100 Hz in FIGS.

FIGS. 7A and 7B are views for explaining a polishing apparatus and a polishing method according to a second embodiment of the present invention, showing a polishing process of a semiconductor device; FIG.
(C) is a sectional view during polishing, and (d) is a sectional view after polishing.

FIG. 8 is a view for explaining a polishing apparatus and a polishing method according to a second embodiment of the present invention, and is a diagram showing a time change of a current flowing in a motor during polishing.

FIG. 9 is a view for explaining a conventional polishing apparatus and a conventional polishing method, and is a diagram showing a time change of a current flowing through a motor during polishing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Surface plate 11 ... Polishing pad 12, 15 ... Motor 13, 16 ... Rotating shaft 14 ... Holding member 17, 18 ... Power supply 19, 20 ... Ammeter 21, 22 ... Filter 23, 24 ... Control device 25 ... Slurry 26 ... Slurry supply nozzle 30 silicon substrate 31 SiO ₂ film 32 Al wiring layer 41 interlayer insulating film 42 barrier metal layer 43 W film

Continued on the front page (72) Inventor Fumihiko Sakata 11-1 Haneda Asahimachi, Ota-ku, Tokyo F-term in EBARA CORPORATION (reference) 3C058 AA07 AA11 AA16 AB01 AB06 BA01 BA09 BB02 BC01 BC02 CB01 DA17

Claims (9)

[Claims] A polishing means for polishing a semiconductor substrate on which a layer to be polished is formed; a surface plate on which the polishing means is laid; holding means for holding the semiconductor substrate; Supporting means for abutting and pressing the surface to be polished of the semiconductor substrate held by the holding means against the polishing means; driving means for rotating the platen and the holding means in a horizontal plane; and the driving means driven by the driving means A friction detecting means for detecting friction between the polishing means on the surface plate and a polished surface of the semiconductor substrate held by the holding means; and a measurement value indicating the friction detected by the friction detecting means. A polishing apparatus comprising: measuring means for measuring only a low-frequency change component of a change component with respect to time. 2. The driving unit is an electric motor, and the friction detecting unit detects the friction by detecting at least one of a current flowing through the electric motor that drives the surface plate and the holding unit. The polishing apparatus according to claim 1, wherein the polishing is performed. 3. The apparatus according to claim 1, wherein the measuring unit has at least one of a noise filter and an arithmetic processing unit configured by an electric circuit.
The polishing apparatus according to the above. 4. The apparatus according to claim 1, wherein said measuring means measures only a change component of 10 Hz or less among time-dependent change components of the measured value indicating the friction detected by said friction detecting means. 3. The polishing apparatus according to claim 3. 5. A step of polishing a surface to be polished formed on a semiconductor substrate; a step of detecting friction between polishing means for polishing the surface to be polished and a surface to be polished of the semiconductor substrate; And a step of measuring only a low-frequency change component of the change component of the measured value indicating the detected friction with respect to time. 6. A step of measuring only a low-frequency change component of the change component of the measured value indicating the detected friction with respect to time, based on a measurement result of the friction having only the low-frequency change component. The polishing method according to claim 5, further comprising a step of calculating an optimum polishing condition. 7. The semiconductor substrate for a test for detecting a state of the polishing means, the semiconductor device being based on the calculated polishing conditions after the step of calculating the polishing conditions. 7. The polishing method according to claim 6, wherein the polishing is performed on the semiconductor substrate on which is formed. 8. A step of measuring only a low-frequency change component of the detected time-dependent change component of the measured value indicating the friction, wherein the measured value indicating the friction indicates an arbitrary frequency of 10 Hz or less from the time-dependent change component. The polishing method according to any one of claims 5 to 7, wherein only the frequency component is measured. 9. The polishing conditions include a polishing time, a pressure applied to the support member during polishing, a rotation speed of a polishing means, a rotation speed of the holding member, and a flow rate of a polishing liquid supplied to the polishing means. The polishing method according to any one of claims 5 to 8, wherein at least one of the polishing methods is used.