JP2023159949A - Parameter adjustment method and polishing endpoint detection system for detecting polishing endpoint - Google Patents

Abstract

To provide a method capable of simply determining a parameter for detecting an accurate polishing endpoint.SOLUTION: This method enables time sequence data which represents a variation of polishing monitoring values along a sample polishing time to be formed, a plurality of candidate values to be formed for each of a plurality of parameters, a plurality of combinations of a plurality of candidate values constituting the plurality of parameters to be generated, a plurality of detection polishing endpoints respectively matching the plurality of combinations to be calculated on the basis of time sequence data, a plurality of detection polishing endpoint TP2 closest to a target detection time TP to be selected from a plurality of detection polishing endpoints, and a plurality of candidate value combinations H5, H4, J3 matching the selected detection polishing endpoint TP2 to be determined as a plurality of parameter numerical values used for detecting polishing endpoint of workpiece.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method for adjusting parameters used to detect the polishing endpoint of workpieces used in the manufacture of semiconductor devices such as wafers, substrates, panels, etc. The present invention also relates to a polishing end point detection system having a function of adjusting parameters used for detecting the polishing end point of such a workpiece.

A polishing module typified by a CMP apparatus is used in the manufacture of semiconductor devices. The wiring structure of a semiconductor device is formed by forming a metal film (such as a copper film) on an insulating film in which a wiring groove is formed, and then removing unnecessary metal film using a polishing module. The polishing module polishes the surface of the wafer by relatively moving the wafer and the polishing pad while supplying a polishing liquid (slurry) to the polishing pad on the polishing table.

The polishing module includes a polishing end point detection device that detects the polishing end point of the wafer. This polishing end point detection device monitors wafer polishing based on polishing index values that indicate the progress of polishing (e.g., table torque current, output signal of an eddy current film thickness sensor, output signal of an optical film thickness sensor). , determine the polishing end point, which is the point at which the metal film reaches the target thickness.

A plurality of parameters are required to detect the polishing end point, and these parameters are set in advance by the user. Examples of the parameters include a threshold value for the polishing index value, a monitoring time for the polishing index value, and the like. The user determines parameters by which an accurate polishing end point can be detected based on actual wafer polishing data or wafer polishing simulation data.

JP2013-176828A

However, in order to determine parameters that can accurately detect the polishing end point, the user is required to understand the polishing end point detection algorithm. Further, even wafers of the same type have variations in surface structure, so even parameters that successfully detect the polishing end point for one wafer may fail to detect the polishing end point for other wafers. In order to determine parameters that can correctly detect the polishing end point for many wafers, it is necessary to repeat trial and error using many wafers, and it takes a long time to determine the parameters.

Therefore, the present invention provides a method and apparatus that can easily determine parameters for detecting an accurate polishing end point.

In one aspect, there is provided a method for adjusting a plurality of parameters for detecting the polishing end point of a workpiece, the method comprising: obtaining a polishing monitoring value indicating the polishing progress of a sample having the same surface structure as the workpiece; generating time-series data representing changes in the polishing monitoring value over polishing time; generating a plurality of candidate values for each of the plurality of parameters; generating combinations, calculating a plurality of detection polishing end points corresponding to the plurality of combinations based on the time series data, selecting a detection polishing end point closest to the target detection time from the plurality of detection polishing end points, and A method is provided in which a combination of the plurality of candidate values corresponding to a selected detected polishing endpoint is determined to be a numerical value of the plurality of parameters used for polishing endpoint detection of the workpiece.

In one aspect, the plurality of candidate values for each parameter are numerical values including a preset reference value, a numerical value smaller than the reference value, and a value larger than the reference value.
In one aspect, the method further includes the steps of creating a sample graph from the time series data and displaying the sample graph on a display screen, and the target detection time is a prespecified polishing time.
In one aspect, the sample is a plurality of samples, and the time series data is a plurality of time series data.
In one aspect, the polishing monitoring value is a current value supplied to a motor for relatively moving a polishing pad against which the sample is pressed and the sample, or a film thickness index value of the sample.

In one aspect, the polishing module includes a polishing progress measuring device provided in the polishing module, and a parameter processing device that automatically adjusts a plurality of parameters for detecting the polishing end point of the workpiece, and the parameter processing device Obtain a polishing monitoring value indicating the polishing progress of the sample output from the polishing progress measuring device during polishing of the sample having the same surface structure as the sample, and representing a change in the polishing monitoring value along the polishing time of the sample. Generating time series data, generating a plurality of candidate values for each of the plurality of parameters, generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters, and generating data corresponding to each of the plurality of combinations. A plurality of detection polishing end points are calculated based on the time series data, a detection polishing end point closest to the target detection time is selected from the plurality of detection polishing end points, and the plurality of candidates corresponding to the selected detection polishing end point are calculated. A polishing endpoint detection system is provided that is configured to determine a combination of values to numerical values of the plurality of parameters used for polishing endpoint detection of the workpiece.

In one aspect, the plurality of candidate values for each parameter are numerical values including a preset reference value, a numerical value smaller than the reference value, and a value larger than the reference value.
In one aspect, the parameter processing device is configured to create a sample graph from the time series data and display the sample graph on a display screen, and the target detection time is a polishing time specified in advance. It is.
In one aspect, the sample is a plurality of samples, and the time series data is a plurality of time series data.
In one embodiment, the polishing progress measuring device is either a torque current detector or a film thickness measuring sensor.

In one aspect, obtaining polishing monitoring values indicative of polishing progress of a sample having the same surface structure as a workpiece; and generating time series data representing changes in the polishing monitoring values over polishing time of the sample. a step of generating a plurality of candidate values for each of the plurality of parameters; a step of generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters; and a step of generating a plurality of candidate values corresponding to each of the plurality of combinations. a step of calculating a detected polishing end point of the detected polishing end point based on the time series data; a step of selecting a detected polishing end point closest to the target detection time from the plurality of detected polishing end points; A computer-readable recording medium is provided that stores a program for causing a computer to execute a step of determining a combination of a plurality of candidate values as a numerical value of the plurality of parameters used for detecting a polishing end point of the workpiece. Ru.

According to the present invention, the user does not need to understand the polishing end point detection algorithm, and the optimal parameters are automatically determined based on the target detection time and time series data obtained from polishing the sample. . Furthermore, since the user does not have to repeat trial and error, the optimal parameters can be determined in a short time.

FIG. 1 is a schematic diagram showing an embodiment of a polishing system including a polishing end point detection system and a polishing module. FIG. 3 is a diagram illustrating an example of a graph showing time-series data representing changes in polishing monitoring values with polishing time of a workpiece. FIG. 7 is a diagram showing another example of a graph showing time-series data representing changes in polishing monitoring values. It is a figure which shows an example of a sample graph. It is a figure showing an example of a plurality of parameters. It is a figure showing other examples of a plurality of parameters. FIG. 7 is a diagram showing still another example of a plurality of parameters. 1 is a flowchart illustrating one embodiment of a method for adjusting multiple parameters. FIG. 7 is a schematic diagram showing another embodiment of the polishing end point detection system. FIG. 7 is a schematic diagram showing still another embodiment of the polishing end point detection system. FIG. 7 is a schematic diagram showing still another embodiment of the polishing end point detection system.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing an embodiment of a polishing system including a polishing end point detection system 7 and a polishing module 1. As shown in FIG. The polishing module 1 is a polishing device (CMP device) that chemically and mechanically polishes a workpiece W. Examples of the workpiece W include wafers, substrates, panels, etc. used in the manufacture of semiconductor devices. The polishing end point detection system 7 is configured to detect the polishing end point of the workpiece W being polished by the polishing module 1 .

The polishing module 1 includes a polishing table 3 that supports a polishing pad 2, and a polishing head 6 connected to the lower end of a head shaft 5. The head shaft 5 is connected to a polishing head rotation motor 12 via a torque transmission mechanism 10 such as a belt and a pulley. The polishing head rotation motor 12 rotates the head shaft 5 via the torque transmission mechanism 10, and the rotation of the head shaft 5 causes the polishing head 6 to rotate about the head shaft 5 in the direction shown by the arrow. The polishing head 6 is configured to be able to hold a workpiece (for example, a wafer) W on its lower surface by vacuum suction.

The head shaft 5 is rotatably held by the head arm 15. The head arm 15 is arranged above the polishing pad 2 and is parallel to the polishing surface 2a of the polishing pad 2. One end of the head arm 15 holds the head shaft 5, and the other end of the head arm 15 is connected to an arm swing motor 16. The arm swing motor 16 is configured to move the polishing head 6 between a polishing position on the polishing table 3 and a transport position outside the polishing table 3 by rotating the head arm 15 by a predetermined angle. has been done.

The polishing table 3 is connected via a table shaft 3a to a table rotation motor 18 disposed below, and the table rotation motor 18 rotates the polishing table 3 about the table shaft 3a in the direction indicated by the arrow. It looks like this. The upper surface of the polishing pad 2 constitutes a polishing surface 2a for polishing the workpiece W. A polishing liquid supply nozzle 20 is arranged above the polishing table 3 to supply a polishing liquid (slurry) to the polishing surface 2a.

Polishing of the workpiece W is performed as follows. While the polishing table 3 and polishing pad 2 are rotated by the table rotation motor 18, polishing liquid is supplied from the polishing liquid supply nozzle 20 to the polishing surface 2a of the polishing pad 2. The polishing head 6 presses the workpiece W against the polishing surface 2 a of the polishing pad 2 while being rotated by the polishing head rotation motor 12 . The workpiece W is polished by a combination of the chemical action of the polishing liquid and the mechanical action of the abrasive grains contained in the polishing liquid and/or the polishing pad 2 . In one embodiment, during polishing of the workpiece W, the polishing head 6 may be oscillated on the polishing surface 2a of the polishing pad 2 by the arm swing motor 16.

Next, the polishing end point detection system 7 will be explained. The polishing end point detection system 7 includes a polishing progress measuring device 30 provided in the polishing module 1 and a parameter processing device 35 that automatically adjusts a plurality of parameters for detecting the polishing end point of the workpiece W. In this embodiment, the polishing progress measuring device 30 includes a torque current detector connected to the table rotation motor 18. The polishing progress measuring device 30 including a torque current detector is configured to measure the current supplied to the table rotation motor 18 (hereinafter referred to as torque current). The torque current is a current necessary for the table rotation motor 18 to rotate the polishing table 3 and polishing pad 2 at a constant speed.

The measured value of the torque current functions as a polishing monitoring value indicating the polishing progress of the workpiece W. That is, during polishing of the workpiece W, the surface of the workpiece W and the polishing surface 2a of the polishing pad 2 come into sliding contact, so that a frictional force is generated between the workpiece W and the polishing pad 2. This frictional force acts on the table rotation motor 18 as resistance torque. The frictional force generated between the workpiece W and the polishing pad 2 changes depending on the surface condition of the workpiece W. For example, when the surface of the workpiece W has a wiring pattern structure, the frictional force changes depending on the state of removal of the film or metal wiring constituting the wiring pattern structure. This change in frictional force can be detected as a change in the torque current supplied to the table rotation motor 18 to rotate the polishing table 3 and polishing pad 2 at a preset speed. The polishing progress measuring device 30 is connected to the parameter processing device 35 and is configured to send a measured value of torque current as a polishing monitoring value to the parameter processing device 35.

The parameter processing device 35 includes a storage device 35a in which a program is stored, and an arithmetic device 35b that executes calculations according to instructions included in the program. The parameter processing device 35 is composed of at least one computer. The storage device 35a includes a main storage device such as a random access memory (RAM), and an auxiliary storage device such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the arithmetic device 35b include a CPU (central processing unit) and a GPU (graphic processing unit). However, the specific configuration of the parameter processing device 35 is not limited to these examples.

The parameter processing device 35 includes a display screen 36 for displaying processing results and processed data by the arithmetic device 35b, and an input device (not shown) for inputting setting values and various information into the storage device 35a. There is.

The parameter processing device 35 may be an edge server connected to the polishing progress measuring device 30 via a communication line, or a cloud server connected to the polishing progress measuring device 30 via a network such as the Internet. The parameter processing device 35 may be a combination of multiple servers. For example, the parameter processing device 35 may be a combination of an edge server and a cloud server connected to each other via a communication network such as the Internet or a local area network. However, the specific configuration of the parameter processing device 35 is not limited to these examples. In one embodiment, the parameter processing device 35 is composed of a plurality of devices, each of which may include a storage device and a calculation device.

The parameter processing device 35 is connected to the polishing control section 40. When the parameter processing device 35 determines the polishing end point of the workpiece W, it sends a polishing end signal to the polishing control section 40, and the polishing control section 40 issues a command to the polishing module 1 to finish polishing the workpiece W.

FIG. 2 is a diagram illustrating an example of a graph showing time-series data representing changes in the polishing monitoring value with the polishing time of the workpiece W. In FIG. 2, the vertical axis represents the polishing monitoring value (ie, the measured value of torque current), and the horizontal axis represents the polishing time of the workpiece W. As the workpiece W is polished, the surface condition of the workpiece W changes. This change in the surface condition of the workpiece W appears as a change in the polishing monitoring value, as shown in FIG.

The polishing end point of the workpiece W is determined based on a plurality of parameters described below and a polishing monitoring value representing the polishing progress of the workpiece W. In this embodiment, the plurality of parameters include a first parameter, a second parameter, and a third parameter described below.
First parameter: detection threshold H
Second parameter: Offset value F
Third parameter: confirmation time J

As shown in FIG. 2, a first parameter, a detection threshold H, is provided for the polishing monitoring value and is compared with the polishing monitoring value. Specifically, the parameter processing device 35 is configured to determine tentative detection times T1 and T2, which are the times when the polishing monitoring value reaches the detection threshold H. Polishing of the workpiece W continues even after the tentative detection times T1 and T2 are determined.

The offset value F, which is the second parameter, is a numerical value subtracted from the detection threshold value H, which is the first parameter. That is, the parameter processing device 35 calculates the reset threshold R by subtracting the offset value F from the detection threshold H.

The confirmation time J, which is the third parameter, is a comparison time starting from the tentative detection time. The parameter processing device 35 starts comparing the polishing monitoring value and the reset threshold value R when the provisional detection time point is determined. If the polishing monitoring value falls below the reset threshold R before the confirmation time J has elapsed, the parameter processing device 35 cancels the provisional detection time point.

In the embodiment shown in FIG. 2, the multiple parameters used for the polishing endpoint are the three parameters described above, but two parameters, or four or more parameters may also be used. Furthermore, the detection threshold, offset value, and confirmation time as parameters are examples, and the specific types of parameters are not limited to the detection threshold, offset value, and confirmation time.

In the example shown in FIG. 2, the provisional detection time T1 is the time when the polishing monitoring value reaches the detection threshold H for the first time. However, the polishing monitoring value falls below the reset threshold R before the confirmation time J has elapsed from the provisional detection time T1. Therefore, the parameter processing device 35 cancels the provisional detection time T1.

The tentative detection time T2 is the time when the polishing monitoring value reaches the detection threshold H again. The polishing monitoring value continues to rise even after the provisional detection time T2, and the polishing monitoring value does not fall below the reset threshold R within the confirmation time J starting from the provisional detection time T2. When the confirmation time J has elapsed, the parameter processing device 35 identifies the tentative detection time point T2 as the detected polishing end point. Further, the parameter processing device 35 sends a polishing end point signal to the polishing control section 40. Upon receiving the polishing end point signal, the polishing control section 40 issues a command to the polishing module 1 to finish polishing the workpiece W.

The time series data shown in FIG. 2 includes a maximum point MP1 and a minimum point MP2 of the polishing monitoring value. The provisional detection time T2, which is recognized as the detection polishing end point, is the time detected after the maximum point MP1 and the minimum point MP2 appear. However, for other workpieces with the same surface structure, the polishing monitoring values may vary in different ways. For example, in another time-series data of the polishing monitoring value shown in FIG. 3, the polishing monitoring value decreases after the tentative detection time T1 is detected, but does not fall below the reset threshold R. Therefore, the provisional detection time T1, which is the time before the maximum point MP1 and the minimum point MP2 appear, is recognized as the detection polishing end point. As a result, the parameter processing device 35 fails to detect the polishing end point. In order to prevent such failure in polishing end point detection, it is necessary to adjust parameters.

Therefore, the parameter processing device 35 adjusts the above parameters as follows.
First, a sample having the same surface structure as the workpiece W is polished by the polishing module 1. For example, if the workpiece W is a wafer having a surface structure constituting a copper wiring pattern, the sample is also a wafer having a surface structure constituting the same copper wiring pattern. That is, the workpiece W and the sample have the same surface structure and the same surface material. In this specification, "the same" means not only completely the same, but also substantially the same in light of common general technical knowledge.

The sample is polished under the same polishing conditions as the workpiece W. The polishing conditions include the rotational speed of the polishing table 3, the rotational speed of the polishing head 6, the pressing force of the polishing head 6 against the workpiece W, the type of polishing liquid, and the flow rate of the polishing liquid.

The polishing progress measuring device 30 measures torque current while polishing a sample. The parameter processing device 35 acquires a torque current measurement value indicating the polishing progress of the sample, that is, a polishing monitoring value, from the polishing progress measuring device 30, and detects the change in the polishing monitoring value (i.e., torque current measurement) along the polishing time of the sample. Generate time-series data representing changes in values). This time series data is stored in the storage device 35a of the parameter processing device 35. Further, the parameter processing device 35 creates a sample graph from the time series data.

FIG. 4 is a diagram showing an example of a sample graph. The sample graph is displayed on the display screen 36 (see FIG. 1) of the parameter processing device 35. The user specifies the target detection time point TP based on the sample graph on the display screen 36. The target detection time point TP is a point that is an index of the polishing end point of the sample. The target detection time point TP may be specified by the user clicking a point on the sample graph appearing on the display screen 36 with a mouse. The target detection time TP is a polishing time corresponding to a designated point on the sample graph displayed on the display screen 36. Alternatively, the target detection time point TP may be specified by the user inputting the numerical value of the target detection time point TP into the parameter processing device 35 using an input device (not shown) such as a keyboard. The designation of the target detection time point TP may be executed by the parameter processing device 35 based on the shape of the sample graph.

The parameter processing device 35 generates a plurality of candidate values for each of the plurality of parameters. That is, the parameter processing device 35 generates a plurality of candidate values (for example, H1, H2, ..., H10) for the first parameter (detection threshold), and generates a plurality of candidate values (for example, H1, H2, ..., H10) for the second parameter (offset value). For example, F1, F2, ..., F5) are generated, and a plurality of candidate values (for example, J1, J2, ..., J5) are generated for the third parameter (confirmation time). In this embodiment, the plurality of candidate values for each parameter are numerical values including a preset reference value, a numerical value smaller than the reference value, and a value larger than the reference value. The reference value may be set by the user, or may be generated by the parameter processing device 35 based on past polishing data.

The parameter processing device 35 generates a plurality of combinations of the plurality of candidate values that constitute the first parameter, the second parameter, and the third parameter. For example, from 10 candidate values for the first parameter (H1 to H10), 5 candidate values for the second parameter (F1 to F5), and 5 candidate values for the third parameter (J1 to J5), Combinations of pieces can be generated.

The parameter processing device 35 calculates a plurality of detected polishing end points corresponding to the plurality of combinations of generated candidate values, respectively, based on the time series data of the sample. FIG. 5 is a sample graph showing an example of the detected polishing end point TP1 corresponding to the first combination of candidate values (H4, F3, J1), and FIG. 6 is a sample graph showing the second combination of candidate values (H5, F4, J1). FIG. 7 is a sample graph showing an example of the detected polishing end point TP2 corresponding to the third combination of candidate values (H9, F5, J4). be.

As shown in FIGS. 5 to 7, the parameter processing device 35 calculates the detected polishing end point for each of the plurality of combinations of generated candidate values based on sample time series data. As can be seen from FIGS. 5 to 7, the calculated detected polishing end points TP1, TP2, and TP3 differ depending on the combination of parameter candidate values.

The parameter processing device 35 selects the detected polishing end point closest to the target detection time point TP designated by the user from the calculated detected polishing end points TP1, TP2, and TP3. In the examples shown in FIGS. 5 to 7, the detected polishing end point TP2 shown in FIG. 6 is closest to the target detection time TP, so the parameter processing device 35 selects the detected polishing end point TP2. Then, the parameter processing device 35 converts the second combination of candidate values (H5, F4, J3) corresponding to the selected detected polishing end point TP2 into numerical values of a plurality of parameters used for detecting the polishing end point of the workpiece W. decided on. The determined values of the plurality of parameters (H5, F4, J3) are the values used to calculate the detected polishing end point TP2 closest to the target detection time TP, so accurate polishing end point detection of the workpiece W is expected. be done.

According to the embodiments described above, the user does not need to understand the algorithm for detecting the polishing end point. The parameter processing device 35 can automatically determine optimal parameters based on the target detection time TP and time series data obtained from polishing the sample. Furthermore, since the user does not have to repeat trial and error, the optimal parameters can be determined in a short time.

FIG. 8 is a flowchart illustrating one embodiment of a method for adjusting a plurality of parameters for detecting the polishing end point of a workpiece W.
In step 1, a sample having the same surface structure as the workpiece W is polished by the polishing module 1. The sample is polished under the same polishing conditions as the workpiece W. The polishing progress measuring device 30 measures torque current while polishing a sample.
In step 2, the parameter processing device 35 acquires a torque current measurement value indicating the polishing progress of the sample, that is, a polishing monitoring value, from the polishing progress measuring device 30.

In step 3, the parameter processing device 35 generates time-series data representing changes in the polishing monitoring value (i.e., changes in the measured torque current value) over the polishing time of the sample.
In step 4, the parameter processing device 35 creates a sample graph from the time series data.
In step 5, a target detection time point is specified by the user or the parameter processing device 35 based on the sample graph.
In step 6, the parameter processing device 35 generates a plurality of candidate values for each of the plurality of parameters. The plurality of candidate values for each parameter may be continuous or discrete numerical values.

In step 7, the parameter processing device 35 generates a plurality of combinations of a plurality of candidate values constituting a plurality of parameters.
In step 8, the parameter processing device 35 calculates a plurality of detected polishing end points corresponding to the plurality of combinations of generated candidate values, respectively, based on the sample time series data or the sample graph.
In step 9, the parameter processing device 35 selects the detected polishing end point closest to the target detection time point designated in step 5 from among the calculated detected polishing end points.
In step 10, the parameter processing device 35 determines a combination of candidate values corresponding to the selected detected polishing end point as numerical values of a plurality of parameters used for detecting the polishing end point of the workpiece W.

The parameter processing device 35 operates according to instructions included in a program electrically stored in the storage device 35a. That is, the parameter processing device 35 acquires a polishing monitoring value indicating the polishing progress of a sample having the same surface structure as the workpiece W, and acquires time series data representing changes in the polishing monitoring value along the polishing time of the sample. a step of generating a plurality of candidate values for each of the plurality of parameters; a step of generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters; and a step of generating a plurality of candidate values for each of the plurality of parameters; A step of calculating a detection polishing end point based on time series data, a step of selecting a detection polishing end point closest to the target detection time from a plurality of detection polishing end points, and a step of selecting a plurality of candidate values corresponding to the selected detection polishing end point. A step of determining a combination of numerical values of a plurality of parameters used for detecting the polishing end point of the workpiece W is performed.

A program for causing the parameter processing device 35 to execute these steps is recorded on a computer-readable recording medium that is a non-temporary tangible object, and is provided to the parameter processing device 35 via the recording medium. Alternatively, the program may be input to the parameter processing device 35 via a communication network such as the Internet or a local area network.

In one embodiment, multiple samples having the same surface structure as the workpiece W to be polished may be polished to obtain multiple time series data of polishing monitoring values. The parameter processing device 35 creates a plurality of sample graphs from a plurality of time series data and displays them on the display screen 36. The user or the parameter processing device 35 specifies a plurality of target detection points for each of the plurality of sample graphs. In the same manner as described above, the parameter processing device 35 determines a plurality of combinations of numerical values of the first parameter, second parameter, and third parameter based on the plurality of sample graphs and the plurality of corresponding target detection points. . The parameter processing device 35 determines (uses) one of the determined combinations as the numerical values of the multiple parameters used to detect the polishing end point of the workpiece W.

In the embodiments described so far, the polishing monitoring value is a measurement of the torque current that changes due to friction between the workpiece W and the polishing pad 2. The frictional force generated between the workpiece W and the polishing pad 2 occurs as the workpiece W and the polishing pad 2 move relative to each other. The table rotation motor 18 is an example of a motor that moves the workpiece W (and sample) and the polishing pad 2 relative to each other. The frictional force generated between the workpiece W and the polishing pad 2 is applied to the polishing head rotation motor 12 that rotates the polishing head 6 while the polishing head 6 is pressing the workpiece W (and sample) against the polishing pad 2. It also causes a change in the supplied torque current. Accordingly, in one embodiment, the polishing progress measuring device 30 may be a torque current detector that measures the torque current supplied to the polishing head rotation motor 12, as shown in FIG. Furthermore, when the polishing head 6 is oscillated by the arm oscillation motor 16 during polishing of the workpiece W (and sample), the polishing progress measuring device 30 is connected to the arm oscillation motor 16 as shown in FIG. It may also be a torque current detector that measures the supplied torque current.

Although the polishing end point detection system 7 described so far uses the measured value of torque current as the polishing monitoring value, the polishing monitoring value is not limited to the measured value of torque current. In one embodiment, as shown in FIG. 11, the polishing progress measuring device 30 is a film thickness measurement sensor that measures the film thickness of the workpiece W (and the sample), and the polishing monitoring value is a film thickness measurement sensor that measures the film thickness of the workpiece W (and the sample). may be the film thickness index value. In the embodiment shown in FIG. 11, the film thickness measurement sensor is disposed within the polishing table 3 and rotates together with the polishing table 3. The film thickness measurement sensor is configured to measure the film thickness of the workpiece W (and the sample) while crossing the workpiece W (and the sample) on the polishing pad 2 . Examples of film thickness measurement sensors include eddy current sensors and optical sensors. A known structure for measuring film thickness using such a film thickness measurement sensor can be adopted.

The embodiments described above have been described to enable those skilled in the art to carry out the invention. Various modifications of the above embodiments can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the invention is not limited to the described embodiments, but is to be construed in the broadest scope according to the spirit defined by the claims.

W Workpiece 1 Polishing module 2 Polishing pad 2a Polishing surface 3 Polishing table 3a Table axis 5 Head shaft 6 Polishing head 7 Polishing end point detection system 10 Torque transmission mechanism 12 Polishing head rotation motor 15 Head arm 16 Arm swing motor 18 Table rotation motor 20 Polishing liquid supply nozzle 30 Polishing progress measuring device 35 Parameter processing device 36 Display screen 40 Polishing control section

Claims (11)

A method of adjusting multiple parameters for detecting a polishing end point of a workpiece, the method comprising:
obtaining a polishing monitoring value indicating the polishing progress of a sample having the same surface structure as the workpiece;
generating time series data representing changes in the polishing monitoring value along polishing time of the sample;
generating a plurality of candidate values for each of the plurality of parameters;
generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters;
Calculating a plurality of detected polishing end points corresponding to the plurality of combinations based on the time series data,
selecting the detection polishing end point closest to the target detection time from the plurality of detection polishing end points;
The method includes determining a combination of the plurality of candidate values corresponding to the selected detected polishing endpoint as numerical values of the plurality of parameters used for polishing endpoint detection of the workpiece. The method according to claim 1, wherein the plurality of candidate values for each parameter are numerical values including a preset reference value, a numerical value smaller than the reference value, and a value larger than the reference value. The method includes:
Create a sample graph from the time series data,
further comprising the step of displaying the sample graph on a display screen,
The method according to claim 1, wherein the target detection time is a prespecified polishing time. The sample is a plurality of samples,
The method according to claim 1, wherein the time series data is a plurality of time series data. The method according to claim 1, wherein the polishing monitoring value is a current value supplied to a motor for relatively moving a polishing pad against which the sample is pressed and the sample, or a film thickness index value of the sample. . A polishing progress measuring device installed in the polishing module,
Equipped with a parameter processing device that automatically adjusts multiple parameters to detect the polishing end point of the workpiece,
The parameter processing device includes:
Obtaining a polishing monitoring value indicating the polishing progress of the sample output from the polishing progress measuring device during polishing of the sample having the same surface structure as the workpiece;
generating time series data representing changes in the polishing monitoring value along polishing time of the sample;
generating a plurality of candidate values for each of the plurality of parameters;
generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters;
Calculating a plurality of detected polishing end points corresponding to the plurality of combinations based on the time series data,
selecting the detection polishing end point closest to the target detection time from the plurality of detection polishing end points;
A polishing endpoint detection system configured to determine a combination of the plurality of candidate values corresponding to the selected detected polishing endpoint as a numerical value of the plurality of parameters used for polishing endpoint detection of the workpiece. . 7. The polishing end point detection system according to claim 6, wherein the plurality of candidate values for each parameter are numerical values including a preset reference value, a numerical value smaller than the reference value, and a value larger than the reference value. The parameter processing device includes:
Create a sample graph from the time series data,
The sample graph is configured to be displayed on a display screen,
7. The polishing end point detection system according to claim 6, wherein the target detection time is a polishing time specified in advance. The sample is a plurality of samples,
The polishing end point detection system according to claim 6, wherein the time series data is a plurality of time series data. 7. The polishing end point detection system according to claim 6, wherein the polishing progress measuring device is one of a torque current detector and a film thickness measuring sensor. obtaining polishing monitoring values indicating the polishing progress of a sample having the same surface structure as the workpiece;
generating time series data representing changes in the polishing monitoring value over polishing time of the sample;
generating a plurality of candidate values for each of the plurality of parameters;
generating a plurality of combinations of the plurality of candidate values constituting the plurality of parameters;
calculating a plurality of detected polishing end points corresponding to the plurality of combinations based on the time series data;
selecting a detection polishing end point closest to the target detection time from the plurality of detection polishing end points;
A program for causing a computer to execute a step of determining a combination of the plurality of candidate values corresponding to the selected detected polishing end point as a numerical value of the plurality of parameters used for detecting the polishing end point of the workpiece. A recorded computer-readable recording medium.

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