JPH09290363A - Polishing method and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide a replacing period of a polishing pad in accordance with its wearing condition, by deciding the replacing period of the polishing pad from its height when it is controlled so as to fix a pressure applied to the polishing pad. SOLUTION: In a device controlling computer 8, a polishing pad replacement indicating part 10 and a threshold value setting part 11 are provided, by these parts, a polishing pad replacement indicating means is constituted. In the threshold setting part 11, a threshold value of polishing pad height and/or polishing pad pressure for deciding replacement timing of a polishing pad is input and stored. In the polishing pad replacement indicating part 10, a threshold value stored in the threshold value setting part 11 is compared with a measured value measured by a polishing pad pressure measuring means 6 or polishing pad height measuring means 7, whether the polishing pad is in a replacement period or not is decided, indication is output.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a silicon wafer,
The present invention relates to a polishing method for determining a replacement time of a polishing pad in a polishing apparatus for polishing a planar substrate such as a quartz substrate or a glass substrate, particularly a silicon wafer in the course of an LSI manufacturing process.
Further, the present invention relates to a polishing apparatus capable of determining the replacement time of the polishing pad.

[0002]

2. Description of the Related Art A polishing pad in a polishing apparatus is replaced when a predetermined operation time has passed. This is because the polishing rate changes depending on the wear state of the polishing pad, and when the thickness of the polishing pad decreases by a predetermined amount or more, the polishing rate rapidly decreases. This change in the polishing rate is, for example, in a polishing pad having a groove formed on the surface, the surface of the polishing pad is worn away and the depth of the groove is reduced as the operating time elapses.
It is considered that this occurs because the amount of the slurry-like polishing agent passing through the groove decreases and the polishing efficiency decreases. However, it is also known that a similar phenomenon occurs in a polishing pad having no groove on the surface.

Conventionally, the replacement of the polishing pad has been carried out at the stage when the operating time determined based on the operating experience has elapsed as described above, and has been carried out regardless of the worn state of the polishing pad. Therefore, the degree of wear of the polishing pad varies widely, and not only the polishing pad that can be used has been replaced, but also a problem such as insufficient polishing of the wafer has occurred due to polishing with the polishing pad having a large degree of wear.

As for a semiconductor manufacturing apparatus, as a method for determining the maintenance time, processing intensities are defined in advance for processing under various conditions and tabulated, and the processing conditions are obtained by monitoring the apparatus, and the processing conditions are determined. There is proposed a method of judging the maintenance time by integrating the processing intensity for the above (Japanese Patent Laid-Open No. 63-10233).
No. 3).

However, in this method, in order to obtain the processing condition, the signal output from the device must be constantly monitored, and the load on the signal processing device is very large. Further, since the processing intensities are integrated to determine the maintenance timing, it is necessary to accurately tabulate the processing intensities in order to accurately determine the maintenance timing. However, this tabulation is actually difficult.

Therefore, when this method is applied to the judgment of the replacement time of the polishing pad, the computer for controlling the apparatus accumulates the data for cumulatively calculating the wear amount of the pad and further obtains it from there. It is necessary to store the estimated value of the abrasion amount of the polishing pad thus obtained, which imposes a heavy load on the computer for controlling the apparatus. In addition, it is necessary to accurately table the amount of wear of the polishing pad,
This tabulation is difficult.

[0007]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and it is not necessary to constantly monitor the apparatus, and the polishing is performed according to the wear state of the polishing pad. It is intended to provide a polishing method capable of determining a pad replacement time. The present invention also provides a polishing apparatus capable of determining the replacement time of the polishing pad.

[0008]

According to the polishing method of the present invention, a polishing pad adhered to a polishing surface plate is pressed against a sample held on a sample table, and an abrasive is applied between the sample and the polishing pad. A polishing method of supplying and rotating a sample table and / or a polishing platen to polish a sample, wherein the height of the polishing pad when the height of the polishing pad is controlled so that the pressure applied to the polishing pad is constant. The feature is that the polishing pad replacement time is determined from this.

Controlling the height of the polishing pad so that the pressure applied to the polishing pad is constant means that the pressure applied to the polishing pad changes as the wear state of the polishing pad changes. This means that the height of the polishing pad is changed so as to be controlled. However, this control does not have to be continuously performed at all times, and may be performed when determining the replacement time of the polishing pad.

Further, the polishing method of the present invention is characterized in that the polishing pad replacement timing is determined from the pressure applied to the polishing pad when the polishing pad height is controlled to be constant.

Controlling the polishing pad height so that it is constant means that it is controlled so as to be constant over time. However, this control does not have to be continuously performed at all times, and may be performed when determining the replacement time of the polishing pad.

Further, the polishing apparatus of the present invention presses the polishing pad adhered to the polishing plate against the sample held on the sample table, supplies the polishing agent between the sample and the polishing pad, and And / or a polishing device for rotating a polishing platen to polish a sample, the polishing pad height measuring means for measuring a height of the polishing pad, and the polishing pad pressure measuring means for measuring a pressure applied to the polishing pad. Polishing pad height control means for controlling the polishing pad height according to the polishing pad height or polishing pad pressure, and a polishing pad replacement instruction for issuing a polishing pad replacement instruction based on the measurement result of the polishing pad pressure or polishing pad height And means.

The pressure applied to the polishing pad means the pressure when the sample is pressed against the polishing pad.

The height of the polishing pad may be determined with reference to a portion of the polishing pad which is not worn, for example, the position of the back surface of the polishing pad, and the position of the polishing platen whose positional relationship with the polishing pad is kept constant. You may use. The height is basically the distance from the sample on the sample table,
If it is a position where the positional relationship with the sample is kept constant, the distance from it can be used as a substitute. For example, if the position of the sample on the sample table is kept constant from the floor, the distance from the floor can be used. Can be used instead.

FIG. 10 is a graph showing a general relationship between the polishing pad thickness and the polishing rate. When the thickness of the polishing pad becomes smaller than the predetermined thickness d _th , the polishing rate sharply decreases. This change in the thickness of the polishing pad can be understood as a change in the height of the polishing pad or a change in the pressure applied to the polishing pad.

FIG. 11A shows a general usage time of the polishing pad and the height of the polishing pad when polishing is performed by controlling the height of the polishing pad so that the pressure applied to the polishing pad becomes constant. FIG. 11B is a graph showing a relationship, and FIG. 11B is a graph showing a general relationship between the polishing pad height and the polishing rate when the same control is performed. The height of the polishing pad is represented by the height from the floor.

As shown in FIG. 11A, since the thickness of the polishing pad becomes thinner as the polishing pad is used, the height of the polishing pad becomes lower if the pressure applied to the polishing pad is controlled to be constant. come.

Further, as shown in FIG. 11 (b), when the height of the polishing pad becomes lower than a predetermined height h _th , the polishing rate sharply decreases. This is because the polishing pad thickness became smaller than the predetermined thickness d _th .

FIG. 12 (a) is a graph showing the general relationship between the use time of the polishing pad and the pressure applied to the polishing pad when polishing is performed with the polishing pad height kept constant, and FIG. 12 (b) is a graph. 3 is a graph showing a general relationship between the pressure applied to the polishing pad and the polishing rate when polishing under the same conditions.

As shown in FIG. 12 (a), since the thickness of the polishing pad becomes thinner as the polishing pad is used, the pressure applied to the polishing pad decreases if the polishing pad height is controlled to be constant. .

Further, as shown in FIG. 12B, when the pressure applied to the polishing pad becomes lower than the predetermined pressure P _th , the polishing rate sharply decreases. This is because the polishing pad thickness has become thinner than the predetermined thickness d _th .

Therefore, when the pressure applied to the polishing pad or the height of the polishing pad is controlled to be constant, the replacement time of the polishing pad can be determined from the height of the polishing pad or the pressure applied to the polishing pad, respectively.

Further, since the abrasion amount of the polishing pad at that time is estimated and the polishing pad replacement time is determined, it is not necessary to cumulatively calculate the estimated value of the abrasion amount of the polishing pad, and it is necessary to constantly monitor the apparatus. Nor.

Further, according to the apparatus of the present invention, polishing pad height measuring means for measuring the height of the polishing pad, polishing pad pressure measuring means for measuring the pressure applied to the polishing pad,
Polishing pad height control means for controlling the polishing pad height by polishing pad height or polishing pad pressure, and polishing pad replacement instruction means for issuing a polishing pad replacement instruction based on the measurement result of the polishing pad pressure or polishing pad height Since it is provided with the above, it is possible to determine the replacement time of the polishing pad by the above method.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION An example of a polishing pad replacement timing determining method and a polishing apparatus in the polishing method of the present invention will be described.

(Example of Apparatus of the Present Invention) FIG. 1 is a block diagram of a polishing apparatus of the present invention. This polishing apparatus is an apparatus for polishing the wafer 1 by rotating the wafer 1 and the polishing pad 2 in contact with each other while supplying a slurry-like polishing agent between the polishing pad 2 and the wafer (sample) 1. The polishing pad 2 is attached to the polishing platen 4, and the wafer 1 is held on the sample table 3. Either or both of the polishing platen 4 and the sample table 3 are configured to be rotatable around the central axis of the polishing platen or the sample table. In order to press the polishing pad 2 against the wafer 1 at a predetermined pressure, the polishing platen 4 is pushed down via a fulcrum (not shown) by, for example, two air cylinders (not shown) of high pressure and low pressure. Is configured as follows.

The pressure applied to the polishing pad (pressure applied to the polishing platen) when the polishing pad 2 is pressed against the wafer 1 is measured by the polishing pad pressure measuring means 6. For example, when the pressure is applied to the polishing platen by the two air cylinders as described above, the signals of the pressure values of the two air cylinders may be fetched.

The polishing pad height measuring means 7 measures the height of the polishing pad 2 (for example, the height of the back surface of the polishing pad 2 or the height at a predetermined position of the polishing platen). As the polishing pad height measuring means 7, for example, an optical means such as a laser outer diameter meter may be used.

The apparatus control computer 8 is provided with an apparatus control section 9 for managing all the operations of the apparatus. For example, the pressure applied to the polishing pad measured by the polishing pad pressure measuring means 6 is used to polish the polishing platen 4. Can be vertically moved by the polishing platen driving device 5 to polish the sample while keeping the pressure applied to the polishing pad constant. Further, using the value of the polishing pad height measured by the polishing pad height measuring means 7,
It is also possible to vertically move the polishing platen 4 by the polishing platen drive device 5 to polish the sample while keeping the polishing pad height constant.

The apparatus control computer 8 is further provided with a polishing pad replacement instructing section 10 and a threshold setting section 11, which constitute polishing pad replacement instructing means. A threshold value of the polishing pad height and / or polishing pad pressure for determining the replacement time of the polishing pad is input and stored in the threshold value setting unit 11. The polishing pad replacement instructing unit 10 compares the threshold value stored in the threshold value setting unit 11 with the measurement value measured by the polishing pad pressure measuring unit 6 or the polishing pad height measuring unit 7 to replace the polishing pad. It is determined whether or not, and an instruction is given.

(First Example of the Method of the Present Invention) FIG. 2 is a flow chart for determining the replacement time of the polishing pad of the first example of the method of the present invention. In this first example, the polishing pad replacement timing is determined from the height of the polishing pad when the height of the polishing pad is controlled so that the pressure applied to the polishing pad becomes constant. As described above, when the height of the polishing pad becomes lower than the predetermined height, the polishing rate is rapidly reduced, and the polishing pad replacement timing is determined.

The procedure until the device control computer 8 gives an instruction indicating that it is time to replace the polishing pad will be described below based on this flowchart.

For the polishing pad used in the apparatus, the polishing rate relative to the polishing pad height is measured in advance. When using a plurality of types of polishing pads, measurement is performed for each polishing pad (step S1).

From the measurement result of the polishing rate with respect to the polishing pad height, the polishing pad height (hereinafter referred to as the polishing pad use limit height) which sharply decreases the polishing rate and affects the apparatus performance is determined. If multiple types of polishing pads are used, make a decision for each polishing pad.

This polishing pad useable height limit may be determined based on the operation experience up to that point, or the slope of the polishing rate graph with respect to the polishing pad height may be a predetermined value or more (for example, dy / dx ≧ a, However, it may be determined by a method of setting the polishing pad height such that y: polishing rate and x: polishing pad height (step S2).

The threshold value of the polishing pad to be used is set in the threshold value setting section 11. This setting can be done either by entering the maximum usable height of each polishing pad in advance in a table format and specifying the type of polishing pad when using it, or by directly specifying the maximum usable height of the pad to be used. , Whichever is acceptable (step S3).

The polishing apparatus is activated. The height of the polishing pad is controlled so that the pressure applied to the polishing pad becomes constant when the polishing pad is pressed against the sample, and the polishing pad height measuring means 7 measures the polishing pad height (step S).
6).

In the polishing pad replacement instructing section 10, the measured polishing pad height is compared with the polishing pad use limit height stored in the threshold setting section 11 (step S).
7). When the polishing pad height is higher than the polishing pad use limit height, it is determined that the polishing pad replacement is unnecessary, and the step of polishing the sample is advanced.

When the polishing pad height is lower than the polishing pad use limit height, an instruction is issued to replace the polishing pad (step S8).

It is judged whether or not the pad is to be replaced, taking into consideration the convenience of operation breaks (step S9).

When the pad is replaced, the above-mentioned steps are repeated from the setting of the use limit height of a new polishing pad in the threshold setting section (step S3).

For example, in an apparatus in which the height of the polishing pad during polishing is controlled so that the pressure applied to the polishing pad becomes constant, the polishing pad wears as the number of times of polishing increases, so that The height of the polishing pad gradually decreases.

Therefore, as in the case of the first example, by instructing to replace the polishing pad at the time when the value of the polishing pad reaches the use limit height or less, an instruction is given to replace the polishing pad, thereby responding to the wear state of the polishing pad. Exchanges can be made at appropriate times.

(Second Example of the Method of the Present Invention) FIG. 3 is a flow chart for determining the replacement time of the polishing pad of the second example of the method of the present invention. In the second example, the polishing pad replacement timing is determined from the pressure applied to the polishing pad when the polishing pad height is controlled to be constant. As described above, when the pressure applied to the polishing pad becomes smaller than a predetermined value, the polishing rate sharply decreases, and the polishing pad replacement timing is determined. This flowchart is different from the flowchart shown in FIG. 2 only in that the polishing pad height is replaced with the polishing pad pressure, and the description of the procedure of this flowchart is omitted.

For example, in an apparatus in which the height of the polishing pad during polishing is set to a constant height regardless of the degree of wear,
The pressure applied to the polishing pad when the pad is moved to the polishing height decreases as the number of polishing operations increases.

Therefore, as in the second example, when the polishing pad pressure shows a value equal to or lower than the polishing pad use limit pressure, an instruction is issued to replace the polishing pad, so that the polishing pad wear state. The replacement can be performed at an appropriate timing according to.

(Third Example of Method of the Present Invention) FIG. 4 is a flow chart for determining the replacement time of the polishing pad of the third example of the present invention. In this third example, the use-limit thickness is set with respect to the thickness of the polishing pad that causes the original change of the polishing rate with time.

The relationship between the height of the polishing pad and the thickness of the polishing pad when the height of the polishing pad is controlled in advance so that the pressure applied to the polishing pad becomes constant, and the height of the polishing pad becomes constant. The relationship between the pressure applied to the polishing pad and the thickness of the polishing pad when the height of the polishing pad is controlled is measured. This relationship is expressed by the device control computer 8
It is stored in the threshold setting unit 11 of.

Based on this flow chart, the procedure until the device control computer 8 gives an instruction indicating that the polishing pad replacement time has come will be described.

For the polishing pad used in the apparatus, the polishing rate with respect to the polishing pad thickness is measured in advance. When using a plurality of types of polishing pads, measurement is performed for each polishing pad (step S1).

From the measurement result of the polishing rate with respect to the polishing pad thickness, the polishing pad thickness (hereinafter, referred to as the polishing pad use limit thickness) which determines the polishing rate sharply and affects the device performance is determined. If multiple types of polishing pads are used, make a decision for each polishing pad.

The polishing pad use limit thickness may be determined based on the operation experience up to that point, or the slope of the polishing rate graph with respect to the polishing pad thickness is a predetermined value or more (for example, dy / dx ≧ b, However, it may be determined by a method of setting the polishing pad thickness such that y: polishing rate and x: polishing pad thickness (step S2).

The polishing pad usage limit thickness to be used is set in the threshold setting unit 11. This setting can be done either by entering the maximum usable thickness of each polishing pad in advance in a table format and specifying the type of polishing pad when using it, or by directly specifying the maximum usable thickness of the pad to be used. , Whichever is acceptable (step S3).

The polishing apparatus is activated. The use limit height and use limit pressure of the polishing pad to be used are also stored in advance in the threshold value setting unit 11 in advance, and the relationship between the height of the polishing pad and the thickness of the polishing pad and the pressure applied to the polishing pad and the thickness of the polishing pad. It is calculated from the relationship (step S4).

A determination method is selected whether the determination is based on the polishing pad height or the polishing pad pressure (step S5). For example, in a device that controls the height of the polishing pad during polishing so that the pressure applied to the polishing pad is constant, select the one that is determined by the polishing pad height,
In a device in which the height of the polishing pad at the time of polishing is set to a constant height, the method of determining by the polishing pad pressure may be selected.

When judging by the height of the polishing pad, the height of the polishing pad is determined so that the pressure of the polishing pad is constant,
At that time, the height of the polishing pad is measured (step S6).
A).

The polishing pad replacement instructing section 10 compares the polishing pad height with the polishing pad use limit height (step S7).

When the polishing pad height is higher than the polishing pad use limit height, it is judged that the polishing pad replacement is unnecessary, and the polishing process is advanced.

When the polishing pad height is lower than the polishing pad use limit height, an instruction is issued to replace the polishing pad (step S8).

In the case of judging by the polishing pad pressure, the height of the polishing pad is made constant and the pressure applied to the polishing pad when the pad is moved to the polishing height is measured (step S6B).

In the polishing pad exchange instructing section 10, the pressure applied to the polishing pad is compared with the polishing pad use limit pressure (step S7).

When the polishing pad pressure is higher than the polishing pad use limit pressure, it is determined that the polishing pad need not be replaced, and the polishing process is advanced.

When the polishing pad pressure is lower than the polishing pad use limit pressure, an instruction is issued to replace the polishing pad (step S8).

Considering the convenience of operation breaks, it is determined whether or not pad replacement is to be performed (step S9).

When the pad is to be replaced, the above-mentioned steps are repeated from the setting of the use limit height of a new polishing pad in the threshold setting section (step S3).

According to the third example, it is possible to determine the replacement time of the polishing pad by setting the use limit thickness of the polishing pad which causes the decrease of the polishing rate. Further, it can be selected from the polishing pad pressure and the polishing pad height, and can be used to judge the replacement time of the polishing pad.

In the above-mentioned first to third examples, the measurement in steps S6, S6A and S6B is preferably performed immediately before the start of polishing, but may be performed at any time during polishing.

The judgment in step S7 is preferably carried out after the polishing is completed, but it may be carried out before the polishing is started.

The above judgment need not be carried out immediately after the replacement of the polishing pad, but may be started after a predetermined operation time. Further, it is not necessary to carry out every time the sample is replaced, and it may be carried out at predetermined intervals of the sample replacement.

[0070]

An embodiment of the present invention will be described. The apparatus of this embodiment is the polishing apparatus shown in FIG. 1, and is an apparatus (CMP apparatus) for chemical mechanical polishing a silicon oxide film (SiO ₂ ) formed on a silicon wafer. Pressurization to the polishing platen 4 was performed by two air cylinders (not shown) of high pressure and low pressure through a fulcrum (not shown). The flowchart of the determination method of this embodiment is shown in FIG.

In the apparatus of this embodiment, the polishing pad pressure measuring means 6 is a portion for taking in signals indicating the pressure values of the two air cylinders, and the pressure applied to the polishing surface plate 4 is evaluated from the pressure values of these air cylinders. did. A laser diameter is used as the polishing pad height measuring means 7, a bar-shaped measurement standard is horizontally provided at a portion supporting the polishing surface plate, and the height of the measurement standard is measured. The height of the polishing pad was determined.

One kind of polishing pad was used, the material thereof was foamed polyurethane, and the thickness before use was 1.27 mm. Width 3mm, depth 0.5 on the surface
mm grooves are provided in the vertical and horizontal directions at intervals of 7 mm. The object to be polished is a silicon wafer on which a silicon oxide film (SiO ₂ ) is formed. The abrasive used was a suspension of fumed silica (SiO _{2 with a} particle size of 0.03 μm).

Using this polishing apparatus, the pressure applied to the polishing pad was controlled to be constant, and the polishing pad height was measured with respect to the polishing pad thickness. The polishing pad pressure at this time was 350 gf / cm ² (= 5 PSI).
Further, the pressure applied to the polishing pad with respect to the polishing pad thickness was measured by controlling the polishing pad height so as to be constant. The height of the polishing pad at this time was the height from the floor with reference to the surface of the polishing platen on the polishing pad side. For these measurements, a polishing pad worn by polishing was used.

FIG. 5 is a graph showing the measurement results of the polishing pad height with respect to the polishing pad thickness. The polishing pad thickness and the polishing pad height were almost proportional.

FIG. 6 is a graph showing the measurement results of the polishing pad pressure with respect to the polishing pad thickness. The polishing pad thickness and the polishing pad pressure were also approximately proportional.

The measurement results of FIGS. 5 and 6 were stored in the threshold value setting section 11 of the computer 8 for controlling the apparatus as the relationship between the polishing pad thickness and the polishing pad height and the relationship between the polishing pad thickness and the polishing pad pressure.

With respect to this polishing pad, the polishing rate with respect to the thickness of the polishing pad was measured (step S1).

FIG. 7 is a graph showing the measurement results of the polishing rate with respect to the thickness of the polishing pad. In this polishing pad, the polishing rate rapidly decreased when the thickness became 750 μm or less. From the result of FIG. 7, the usable limit thickness of this polishing pad was determined to be 750 μm (step S2).

The use limit thickness of this polishing pad is set in the threshold value setting section 11 of the apparatus control computer 8 (step S
3).

After that, the height of the polishing pad was controlled so that the pressure of the polishing pad was kept constant, and the silicon oxide film on the silicon wafer was polished. As the method for determining the polishing pad replacement time, the method of determining from the polishing pad height was selected, and the replacement time of the polishing pad was determined in the loop of steps S5 to S6 according to the flowchart. Then, when an instruction to replace the polishing pad was issued (step S8), the pad was replaced as soon as possible. However, in practice, the polishing pad may not be replaced at the timing when the replacement instruction is issued due to the operation break.

FIG. 8 is a graph showing the amount of abrasion of the polishing pad when the polishing pad is replaced, which is the result of using the method for determining the replacement time of the polishing pad according to the method of the present invention. The number of exchanges of the polishing pad was 94 times, and the wear amount of 94 polishing pads was measured.

FIG. 9 is a graph showing the abrasion amount of the polishing pad when the polishing pad is replaced based on the conventional method in which the replacement time of the polishing pad is determined only by the operation time. The number of times the polishing pad was replaced was 94 times, and the wear amount was measured for the same 94 polishing pads.

By the method of the present invention, the variation in the amount of wear when exchanging the polishing pad was reduced more than before.

In the conventional method, as shown in FIG. 9, the amount of wear of the polishing pad differs depending on the material of the wafer to be polished, so the amount of wear of the pad at a specific polishing time cannot be a specific value. It was not possible to suppress variations in the amount of pad wear at the time of pad replacement. Further, when a plurality of types of polishing pads are used, the variation becomes large.

On the other hand, in the method of the present invention, the amount of wear of the polishing pad is estimated when the polishing pad moves to the polishing position, and therefore the time to replace the polishing pad can be determined according to the state of wear of the polishing pad. Moreover, it is not necessary to constantly monitor the device signal and store the data.

[0086]

As described above in detail, according to the polishing method and the polishing apparatus of the present invention, it is not necessary to constantly monitor the apparatus, and the replacement timing of the polishing pad can be determined according to the worn state of the polishing pad.

As a result, it is possible to avoid the problem that the usable pad is replaced faster than necessary, which is a problem in the prior art, and it is possible to avoid the problem of insufficient polishing due to the pad having a large degree of wear.

[Brief description of drawings]

FIG. 1 is a block diagram of a polishing apparatus of the present invention.

FIG. 2 is a flow chart for determining the replacement time of the polishing pad of the first example of the method of the present invention.

FIG. 3 is a flow chart for determining the replacement time of a polishing pad according to a second example of the method of the present invention.

FIG. 4 is a flowchart for determining a polishing pad replacement time according to a third example of the method of the present invention.

FIG. 5 is a graph showing measurement results of polishing pad height with respect to polishing pad thickness.

FIG. 6 is a graph showing measurement results of polishing pad pressure with respect to polishing pad thickness.

FIG. 7 is a graph showing the measurement results of the polishing rate with respect to the thickness of the polishing pad.

FIG. 8 is a graph showing the amount of polishing pad wear when the polishing pad is replaced, which is the result of using the method for determining the replacement time of the polishing pad according to the method of the present invention.

FIG. 9 is a graph showing the abrasion amount of the polishing pad when the polishing pad is replaced based on the conventional method.

FIG. 10 is a graph showing a general relationship between a polishing pad thickness and a polishing rate.

FIG. 11A is a general relationship between the polishing pad usage time and the polishing pad height when polishing is performed by controlling the polishing pad height so that the pressure applied to the polishing pad is constant. And (b) is a graph showing a general relationship between the height of the polishing pad and the polishing rate when the same control is performed.

FIG. 12 (a) is a graph showing a general relationship between the polishing pad usage time and the pressure applied to the polishing pad when polishing is performed with the polishing pad height kept constant, and FIG.
FIG. 4 is a graph showing a general relationship between the pressure applied to the polishing pad and the polishing rate under the same control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 sample (wafer) 2 polishing pad 3 sample stage 4 polishing surface plate 5 polishing surface plate driving device 6 polishing pad pressure measuring unit 7 polishing pad height measuring means 8 device control computer 9 device control unit 10 polishing pad replacement instruction unit 11 Threshold setting section

Claims (3)

[Claims] 1. A sample table and / or a polishing platen, wherein a polishing pad adhered to a polishing platen is pressed against a sample held on a sample table, and an abrasive is supplied between the sample and the polishing pad. Is a method for polishing a sample by rotating the polishing pad, and determining the replacement time of the polishing pad from the height of the polishing pad when the height of the polishing pad is controlled so that the pressure applied to the polishing pad is constant. A polishing method characterized by: 2. A sample table and / or a polishing platen, wherein a polishing pad adhered to a polishing platen is pressed against a sample held on a sample table and an abrasive is supplied between the sample and the polishing pad. Is a method for polishing a sample by rotating the polishing pad, wherein the polishing pad replacement time is determined from the pressure applied to the polishing pad when the polishing pad height is controlled to be constant. 3. A sample table and / or a polishing platen, wherein a polishing pad adhered to a polishing platen is pressed against a sample held on a sample table and an abrasive is supplied between the sample and the polishing pad. A polishing device for rotating a sample to polish a sample, the polishing pad height measuring means for measuring the height of the polishing pad, the polishing pad pressure measuring means for measuring the pressure applied to the polishing pad, and the polishing pad height or A polishing pad height control means for controlling the height of the polishing pad by the polishing pad pressure, and a polishing pad exchange instructing means for instructing the polishing pad exchange based on the measurement result of the polishing pad pressure or the polishing pad height. Characteristic polishing device.