A monitoring method and system for polishing head based on acoustic waves

Abstract

The present invention provides a method and system for monitoring a polishing head based on acoustic waves. The monitoring method includes: while a test retaining ring rotates around its central axis, an acoustic wave transmission liquid emitting unit is used to spray acoustic wave transmission liquid, forming a first liquid column between the acoustic wave transmission liquid emitting unit and the test retaining ring; simultaneously, the acoustic wave emitting unit is used to transmit a first detection acoustic wave to the test retaining ring through the first liquid column; an acoustic wave receiving unit is used to receive a first feedback acoustic wave after the test retaining ring reflects the first detection acoustic wave; based on the waveform distribution of the first detection acoustic wave and the first feedback acoustic wave, a test surface morphology of the polishing surface of the test retaining ring between the first grooves and the first grooves is obtained; and a morphology analysis unit is used to obtain defect information of the test surface morphology. Through the above-mentioned monitoring method, the quality of the retaining ring can be monitored in real time, avoiding a decrease in product yield due to quality problems of the polishing head.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a monitoring method and a monitoring system for a polishing head based on acoustic waves. Background Art

[0002] With the development of Moore's Law, chemical mechanical planarization (CMP) plays an increasingly important role in the semiconductor process. The polishing head is a key component of CMP equipment, and its quality is directly related to the processing quality of the wafer. The core processing part of the polishing head consists of a retaining ring and a pressure membrane that contact the wafer. The retaining ring has grooves on its surface and contacts the surface of the polishing pad during operation. As the working time increases, its surface wears and the grooves become shallower. At the same time, defects such as chipping and cracks may also appear. At the same time, the grooves in the retaining ring have the function of guiding the polishing liquid. If it is not cleaned properly, crystallization will occur, causing the grooves to become clogged, which in turn affects product processing and reduces the yield. Summary of the Invention

[0003] The technical problem to be solved by the present invention is how to realize online monitoring of the quality of the polishing head and avoid the problem of decreased product yield due to quality problems of the polishing head.

[0004] The present invention provides a monitoring method for a polishing head based on acoustic waves, comprising: providing a test polishing head, the test polishing head comprising a test retaining ring, a grinding surface of the test retaining ring being provided with a plurality of first grooves on one side; during the process of the test retaining ring rotating around the central axis of the test retaining ring, using an acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the test retaining ring between adjacent first grooves and in the first grooves, so that a first liquid column is formed between the acoustic wave transmission liquid emitting unit and the test retaining ring; during the process of using the acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the test retaining ring between adjacent first grooves and in the first grooves, using the acoustic wave transmission liquid emitting unit to emit a first detection acoustic wave to the test retaining ring through the first liquid column; using an acoustic wave receiving unit to receive a first feedback acoustic wave transmitted along the first liquid column after the test retaining ring reflects the first detection acoustic wave; obtaining a test surface morphology of the first groove and the grinding surface of the test retaining ring between the first grooves based on the waveform distribution of the first detection acoustic wave and the first feedback acoustic wave; and using a morphology analysis unit to obtain defect information of the test surface morphology.

[0005] Optionally, it further includes: providing a calibration polishing head, the calibration polishing head including a calibration retaining ring, and a plurality of second grooves are provided on one side of the grinding surface of the calibration retaining ring; the monitoring method of the polishing head based on acoustic waves further includes: during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, using an acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves, so that a second liquid column is formed between the acoustic wave transmission liquid emitting unit and the calibration retaining ring; during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, using an acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves, so that a second liquid column is formed between the acoustic wave transmission liquid emitting unit and the calibration retaining ring; During the process of spraying the acoustic wave transmission liquid in the groove, the acoustic wave transmitting unit is used to transmit the second detection acoustic wave to the calibration retaining ring through the second liquid column; the acoustic wave receiving unit is used to receive the second feedback acoustic wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection acoustic wave; the calibration surface morphology of the grinding surface of the second groove and the calibration retaining ring between the second grooves is obtained according to the waveform distribution of the second detection acoustic wave and the second feedback acoustic wave; the step of using the morphology analysis unit to obtain defect information of the test surface morphology includes: the analysis unit obtains the defect information of the test surface morphology according to the difference between the test surface morphology and the calibration surface morphology.

[0006] Optionally, the method further includes: using a wear analysis unit to obtain the wear amount of the grinding surface of the test retaining ring.

[0007] Optionally, the monitoring method of the polishing head based on acoustic waves also includes: providing a test platform, on which the acoustic test module is arranged; during the process of the calibration retaining ring rotating around the central axis of the calibration retaining ring, the grinding surface of the calibration retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and the surface of the test platform is fixed; according to the time difference between the acoustic wave transmitting unit transmitting the second detection sound wave and the sound wave receiving unit receiving the second feedback sound wave, the calibration distance between the acoustic test module and the grinding surface of the calibration retaining ring is obtained; while the test retaining ring rotates around the measurement During the rotation of the central axis of the test retaining ring, the grinding surface of the test retaining ring faces the test platform and the acoustic test module, and the distance from the surface of the test retaining ring opposite to the grinding surface of the test retaining ring to the surface of the test platform is equal to the distance from the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring to the surface of the test platform; the test distance between the acoustic test module and the grinding surface of the test retaining ring is obtained according to the time difference between the sound wave transmitting unit transmitting the first detection sound wave and the sound wave receiving unit receiving the first feedback sound wave; the wear amount of the grinding surface of the test retaining ring is obtained according to the difference between the test distance and the calibration distance.

[0008] Optionally, it also includes: an acoustic wave transmitting unit, an acoustic wave receiving unit and an acoustic wave transmission liquid transmitting unit forming an acoustic test module; when the test retaining ring rotates around the central axis of the test retaining ring, a plurality of acoustic test modules are distributed along the radial direction of the test retaining ring.

[0009] The present invention also provides a monitoring system for a polishing head based on acoustic waves, which is used to detect a test retaining ring in a test polishing head, wherein a plurality of first grooves are provided on one side of the grinding surface of the test retaining ring, comprising: a rotation driving unit, wherein the rotation driving unit is suitable for driving the test retaining ring to rotate around the central axis of the test retaining ring; an acoustic wave transmission liquid emitting unit, wherein the acoustic wave transmission liquid emitting unit is suitable for spraying acoustic wave transmission liquid on the grinding surface of the test retaining ring between adjacent first grooves and in the first grooves during the test retaining ring rotates around the central axis of the test retaining ring; and a space between the acoustic wave transmission liquid emitting unit and the test retaining ring is suitable for A first liquid column is formed; an acoustic wave emitting unit is suitable for emitting a first detection acoustic wave to the test retaining ring through the first liquid column; an acoustic wave receiving unit is suitable for receiving a first feedback acoustic wave transmitted along the first liquid column after the test retaining ring reflects the first detection acoustic wave; a surface morphology acquisition unit is suitable for acquiring the test surface morphology of the grinding surface of the first groove and the test retaining ring between the first grooves according to the waveform distribution of the first detection acoustic wave and the first feedback acoustic wave; and a morphology analysis unit is suitable for acquiring defect information of the test surface morphology.

[0010] Optionally, it is also suitable for monitoring the calibration retaining ring in the calibration polishing head, the calibration polishing head includes a calibration retaining ring, and a plurality of second grooves are provided on one side of the grinding surface of the calibration retaining ring, and it is characterized in that the rotation drive unit is also suitable for driving the test retaining ring to rotate around the central axis of the test retaining ring; the acoustic wave transmission liquid emitting unit is also suitable for spraying the grinding surface of the calibration retaining ring between adjacent second grooves and the second grooves during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, and the acoustic wave transmission liquid emitting unit and the calibration retaining ring are suitable for forming a gap between the calibration retaining ring and the calibration retaining ring. a second liquid column; the sound wave emitting unit is further adapted to emit a second detection sound wave to the calibration retaining ring through the second liquid column; the sound wave receiving unit is further adapted to receive a second feedback sound wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection sound wave; the surface morphology acquiring unit is further adapted to acquire the calibration surface morphology of the grinding surface of the second groove and the calibration retaining ring between the second grooves according to the waveform distribution of the second detection sound wave and the second feedback sound wave; the morphology analyzing unit acquires defect information of the test surface morphology according to the difference between the test surface morphology and the calibration surface morphology.

[0011] Optionally, the acoustic wave emitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid emitting unit constitute an acoustic test module; the monitoring system of the polishing head based on acoustic waves also includes: a test platform, on which the acoustic test module is arranged; the grinding surface of the calibration retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and the surface of the test platform is fixed; the grinding surface of the test retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the test retaining ring opposite to the grinding surface of the test retaining ring and the surface of the test platform is equal to the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring the distance from the surface of the acoustic test module to the surface of the test platform; a distance acquisition unit, the distance acquisition unit is suitable for acquiring the calibration distance between the acoustic test module and the grinding surface of the calibration retaining ring according to the time difference between the acoustic wave emitting unit emitting the second detection sound wave and the sound wave receiving unit receiving the second feedback sound wave; the distance acquisition unit is also suitable for acquiring the test distance between the acoustic test module and the grinding surface of the test retaining ring according to the time difference between the acoustic wave emitting unit emitting the first detection sound wave and the sound wave receiving unit receiving the first feedback sound wave; a wear amount acquisition unit, the wear amount acquisition unit is suitable for acquiring the wear amount of the grinding surface of the test retaining ring according to the difference between the test distance and the calibration distance.

[0012] Optionally, it also includes: an acoustic wave emitting unit, an acoustic wave receiving unit and an acoustic wave transmission liquid emitting unit forming an acoustic test module; the number of acoustic test modules is several; and the several acoustic test modules are suitable for being distributed radially along the test retaining ring during the process of the test retaining ring rotating around the central axis of the test retaining ring.

[0013] The technical solution of the present invention has the following beneficial effects:

[0014] The present invention provides a method for monitoring a polishing head based on acoustic waves. During the rotation of a test retaining ring about its central axis, an acoustic wave transmission liquid emitting unit is used to spray acoustic wave transmission liquid onto the polishing surface of the test retaining ring between adjacent first grooves and into the first grooves. A first liquid column formed between the acoustic wave transmission liquid emitting unit and the test retaining ring serves as a transmission carrier for the acoustic wave. The acoustic wave emitting unit transmits a first detection acoustic wave to the test retaining ring through the first liquid column, and an acoustic wave receiving unit receives a first feedback acoustic wave that is reflected by the test retaining ring and transmitted along the first liquid column. Both the first detection acoustic wave and the first feedback acoustic wave utilize the strong directionality and long propagation distance of acoustic waves propagating in the first liquid column. Acoustic wave detection is often rapid, convenient, and easy to implement in real time. A morphology analysis unit analyzes the surface morphology of the polishing surface of the test retaining ring in the first grooves and between the first grooves to determine whether the polishing surface of the retaining ring has defects such as chipping or cracks, and to analyze whether crystals have formed within the first grooves. By adopting the above-mentioned monitoring method of the polishing head based on acoustic waves, the quality of the retaining ring on the polishing head can be monitored in real time, thereby avoiding the problem of reduced product yield due to quality problems of the retaining ring of the polishing head.

[0015] Furthermore, the wear acquisition unit can analyze the wear of the retaining ring. Based on the principle of acoustic ranging, the wear acquisition unit stores the distance data from the ground surface of the calibrated retaining ring to the acoustic test module. Because the acoustic test module is stationary, the distance between the ground surface and the acoustic test module increases as the retaining ring wears. Therefore, the wear of the retaining ring is calculated by subtracting the real-time distance data from the calibrated distance data. When the wear reaches a certain level, an alarm is triggered to remind the operator whether to replace the retaining ring.

[0016] Furthermore, several acoustic test modules are arranged along the radial direction of the retaining ring. The radial arrangement of multiple acoustic test modules can obtain the morphological information of different radial positions of the retaining ring. Combined with the polishing head rotating with the retaining ring around its own center, the surface structural morphological details of the grinding surface of the test retaining ring and the grinding surface of the calibration retaining ring can be obtained, ultimately improving the accuracy of the surface structural morphological characteristics of the grinding surface of the test retaining ring and the grinding surface of the calibration retaining ring; at the same time, the calibration distance of the entire test and calibration retaining ring and the test distance of the entire test retaining ring can be obtained, ultimately improving the accuracy of the calibration distance of the calibration retaining ring and the test distance of the test retaining ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the process of the monitoring method of the polishing head based on acoustic waves according to Example 1 of the present application;

[0019] Figure 2 This is a schematic block diagram of a monitoring system for a polishing head based on acoustic waves according to Example 2 of the present application;

[0020] Figure 3 Schematic diagram of waveforms received in different situations according to the embodiment of the present application;

[0021] Reference numerals:

[0022] W0-calibration of the normal waveform of the grinding surface of the retaining ring; W1-calibration of the normal waveform at the groove of the retaining ring; W2-testing the waveform of the internal crack of the retaining ring; W3-testing the waveform of the surface crystallization at the groove of the retaining ring; W4-testing the waveform after the grinding surface of the retaining ring is worn. DETAILED DESCRIPTION

[0023] CMP (chemical mechanical polishing) is a widely used planarization method in semiconductor manufacturing. As a key component of CMP equipment, the polishing head's quality directly impacts wafer processing quality. The core processing portion of the polishing head consists of a retaining ring and a pressure membrane, which contact the wafer. Both the retaining ring and the pressure membrane are mounted on the polishing head. During operation, the pressure membrane presses the wafer against the polishing pad for polishing, while the retaining ring prevents the wafer from slipping. The polishing surface of the retaining ring features oblique grooves, allowing polishing fluid to flow into the polishing head during operation, achieving chemical mechanical polishing.

[0024] However, polishing liquid will flow through the retaining ring groove. As the use time increases, crystals will form inside the groove, causing the groove to be blocked. As a result, the polishing liquid cannot smoothly enter between the wafer and the polishing pad inside the polishing head, affecting the product yield.

[0025] During operation, the retaining ring contacts the surface of the polishing pad. Through continuous friction, the depth of its groove will become shallower and shallower, affecting the flow of polishing liquid and affecting the yield; at the same time, its ability to hold the wafer is also reduced, which increases the risk of the wafer slipping. At this time, the wear limit of the retaining ring is reached and it needs to be replaced; moreover, since the retaining ring is always in a high-pressure working state, it is prone to defects such as edge chipping or cracks, posing a potential danger to wafer processing.

[0026] Aiming at the problem of reduced product yield due to quality problems of polishing heads, the present invention proposes a polishing head monitoring method and monitoring system based on acoustic waves.

[0027] The technical solutions of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Example 1

[0029] This embodiment provides a monitoring method for a polishing head based on acoustic waves. Figure 1 ,include:

[0030] Step S1: providing a test polishing head, wherein the test polishing head comprises a test retaining ring, and a plurality of first grooves are provided on one side of a grinding surface of the test retaining ring;

[0031] Step S2: while the test retaining ring rotates around its central axis, an acoustic wave transmission liquid emitting unit is used to spray an acoustic wave transmission liquid onto the polished surface of the test retaining ring between adjacent first grooves and into the first grooves, thereby forming a first liquid column between the acoustic wave transmission liquid emitting unit and the test retaining ring;

[0032] Step S3: while using the acoustic wave transmission liquid emitting unit to spray the acoustic wave transmission liquid on the polished surface of the test retaining ring between adjacent first grooves and in the first grooves, using the acoustic wave transmission liquid emitting unit to emit a first detection acoustic wave to the test retaining ring through the first liquid column;

[0033] Step S4: using an acoustic wave receiving unit to receive a first feedback acoustic wave transmitted along the first liquid column after the test retaining ring reflects the first detection acoustic wave;

[0034] Step S5: acquiring a test surface topography of the first groove and the polished surface of the test retaining ring between the first grooves according to the waveform distribution of the first detection sound wave and the first feedback sound wave;

[0035] Step S6: Use the morphology analysis unit to obtain defect information of the test surface morphology.

[0036] In this embodiment, the first liquid column formed between the acoustic wave transmission liquid emitting unit and the test retaining ring serves as a transmission carrier for the acoustic wave; both the first detection acoustic wave and the first feedback acoustic wave utilize the characteristics of strong directionality and long propagation distance when the acoustic wave propagates in the first liquid column. Acoustic wave detection is often rapid and convenient, and is easy to achieve real-time control.

[0037] In this embodiment, the surface topography acquisition unit extracts surface topography features corresponding to the first groove and the grinding surface of the test retaining ring between the first grooves. This is based on analyzing and extracting the surface topography information carried by the first feedback sound wave generated by the reflection of the first groove and the grinding surface of the test retaining ring between the first grooves, thereby obtaining the surface topography features. This is because when the first detection sound wave reaches the grinding surface of the test retaining ring between the first grooves and the grinding surface between the first grooves, the surface structural details of the grinding surface of the test retaining ring between the first grooves and the grinding surface between the first grooves modulate the waveform distribution of the first detection sound wave. In other words, the first feedback sound wave reflected from the grinding surface of the test retaining ring between the first grooves and the grinding surface between the first grooves carries associated information about the surface structural topography details of the grinding surface of the test retaining ring between the first grooves and the grinding surface between the first grooves. By analyzing the first feedback sound wave accordingly, the surface structural topography details can be extracted to achieve surface topography feature extraction of the grinding surface of the test retaining ring between the first grooves and the grinding surface between the first grooves.

[0038] In this embodiment, the surface morphology characteristics of the first groove and the grinding surface of the test retaining ring between the first grooves are analyzed by the morphology analysis unit to determine whether the grinding surface of the retaining ring has defects such as chipping or cracks, and whether crystallization occurs inside the first groove. Figure 3 As shown, when there is an internal crack in the test retaining ring, the waveform of the first feedback sound wave received by the surface morphology acquisition unit is shown as the waveform W2 of the internal crack in the test retaining ring; when there is crystallization in the groove of the test retaining ring, the waveform of the first feedback sound wave received by the surface morphology acquisition unit is shown as the waveform W3 of the surface crystallization in the groove of the test retaining ring; when there is wear on the grinding surface of the test retaining ring, the waveform of the first feedback sound wave received by the surface morphology acquisition unit is shown as the waveform W4 after the grinding surface of the test retaining ring is worn; when an abnormality occurs, the operator is reminded by an alarm, and the operator decides whether to take further action.

[0039] By adopting the above-mentioned monitoring method of the polishing head based on acoustic waves, the quality of the retaining ring on the polishing head can be monitored in real time, thereby avoiding the problem of reduced product yield due to quality problems of the retaining ring of the polishing head.

[0040] In this embodiment, it also includes: providing a calibration polishing head, the calibration polishing head includes a calibration retaining ring, and a plurality of second grooves are provided on one side of the grinding surface of the calibration retaining ring; the monitoring method of the polishing head based on acoustic waves also includes: during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, using an acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves, so that a second liquid column is formed between the acoustic wave transmission liquid emitting unit and the calibration retaining ring; during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, using an acoustic wave transmission liquid emitting unit to spray acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves, so that a second liquid column is formed between the acoustic wave transmission liquid emitting unit and the calibration retaining ring; During the process of spraying the acoustic wave transmission liquid in the groove, the acoustic wave transmitting unit is used to transmit the second detection acoustic wave to the calibration retaining ring through the second liquid column; the acoustic wave receiving unit is used to receive the second feedback acoustic wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection acoustic wave; the calibration surface morphology of the grinding surface of the second groove and the calibration retaining ring between the second grooves is obtained according to the waveform distribution of the second detection acoustic wave and the second feedback acoustic wave; the step of using the morphology analysis unit to obtain defect information of the test surface morphology includes: the analysis unit obtains the defect information of the test surface morphology according to the difference between the test surface morphology and the calibration surface morphology.

[0041] like Figure 3 As shown, the normal waveform of the calibration retaining ring grinding surface is shown as normal waveform W0, and the normal waveform at the calibration retaining ring groove is shown as normal waveform W1. By using the above-mentioned acoustic wave-based polishing head monitoring method, the calibration surface topography of the grinding surface of the calibration retaining ring between the second groove and the second groove is obtained. Based on the difference between the surface topography characteristics of the grinding surface of the test retaining ring between the first groove and the first groove, and the calibration surface topography of the grinding surface of the calibration retaining ring between the second groove and the second groove, defect information of the grinding surface of the test retaining ring between the first groove and the first groove is obtained. When an abnormality occurs, an alarm alerts the operator, who then decides whether to take further action.

[0042] The acoustic wave-based polishing head monitoring method further includes: using a wear analysis unit to obtain the wear amount of the grinding surface of the test retaining ring. The wear analysis unit can analyze and determine the wear amount of the grinding surface of the retaining ring, thereby alerting the operator to replace the retaining ring in a timely manner.

[0043] The acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute an acoustic test module. The monitoring method of the polishing head based on acoustic waves also includes: providing a test platform, on which the acoustic test module is arranged; in the process of the calibration retaining ring rotating around the central axis of the calibration retaining ring, the grinding surface of the calibration retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and the surface of the test platform is fixed; according to the time difference between the acoustic wave transmitting unit transmitting the second detection sound wave and the sound wave receiving unit receiving the second feedback sound wave, the distance between the acoustic test module and the grinding surface of the calibration retaining ring is obtained. Calibration distance; during the process of the test retaining ring rotating around the central axis of the test retaining ring, the grinding surface of the test retaining ring faces the test platform and the acoustic test module, and the distance from the surface of the test retaining ring opposite to the grinding surface of the test retaining ring to the surface of the test platform is equal to the distance from the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring to the surface of the test platform; the test distance between the acoustic test module and the grinding surface of the test retaining ring is obtained according to the time difference between the acoustic wave transmitting unit transmitting the first detection sound wave and the sound wave receiving unit receiving the first feedback sound wave; the wear amount of the grinding surface of the test retaining ring is obtained according to the difference between the test distance and the calibration distance.

[0044] In one embodiment, the acoustic wave transmitting unit, the acoustic wave receiving unit, and the acoustic wave transmission liquid transmitting unit constitute an acoustic testing module; during the process of the test retaining ring rotating around the central axis of the test retaining ring, a plurality of acoustic testing modules are distributed along the radial direction of the test retaining ring. The plurality of acoustic testing modules are arranged along the radial direction of the retaining ring. After the test retaining ring rotates once around the central axis of the test retaining ring, the entire surface structural morphology details of all first grooves and the grinding surface of the test retaining ring can be obtained, ultimately improving the accuracy of the first grooves and the grinding surface of the test retaining ring. At the same time, the calibration distance of the entire calibration retaining ring and the test distance of the entire test retaining ring can be tested, ultimately improving the accuracy of the calibration distance of the entire calibration retaining ring and the test distance of the entire test retaining ring.

[0045] Example 2

[0046] This embodiment provides a monitoring system for a polishing head based on acoustic waves, which is used to detect a test retaining ring in a test polishing head. A plurality of first grooves are provided on one side of the grinding surface of the test retaining ring. Figure 2, comprising: a rotation driving unit, the rotation driving unit being adapted to drive the test retaining ring to rotate around the central axis of the test retaining ring; an acoustic wave transmission liquid emitting unit, the acoustic wave transmission liquid emitting unit being adapted to spray acoustic wave transmission liquid onto the grinding surface of the test retaining ring between adjacent first grooves and into the first grooves during the test retaining ring's rotation around the central axis of the test retaining ring, a first liquid column being adapted to be formed between the acoustic wave transmission liquid emitting unit and the test retaining ring; an acoustic wave emitting unit, the acoustic wave emitting unit being adapted to emit a first detection acoustic wave to the test retaining ring through the first liquid column; an acoustic wave receiving unit, the acoustic wave receiving unit being adapted to receive a first feedback acoustic wave transmitted along the first liquid column after the test retaining ring reflects the first detection acoustic wave; a surface morphology acquiring unit, the surface morphology acquiring unit being adapted to acquire the test surface morphology of the first groove and the grinding surface of the test retaining ring between the first grooves according to the waveform distribution of the first detection acoustic wave and the first feedback acoustic wave; and a morphology analyzing unit, the morphology analyzing unit being adapted to acquire defect information of the test surface morphology.

[0047] Specifically, the rotation drive unit is configured to rotate the polishing head, thereby causing the polishing head to rotate the test retaining ring about its central axis. The acoustic wave transmission liquid emitting unit sprays acoustic wave transmission liquid onto the grinding surface of the test retaining ring between adjacent first grooves and into the first grooves during the test retaining ring's rotation, thereby forming a first liquid column between the acoustic wave transmission liquid emitting unit and the test retaining ring. The acoustic wave emitting unit emits a first detection acoustic wave to the test retaining ring via the first liquid column. The acoustic wave receiving unit receives a first feedback acoustic wave transmitted along the first liquid column after the test retaining ring reflects the first detection acoustic wave. The surface topography acquisition unit is configured to extract surface topography features corresponding to the grinding surface of the test retaining ring in the first grooves and between the first grooves. The topography analysis unit analyzes the surface topography features of the grinding surface of the test retaining ring in the first grooves and between the first grooves to determine whether the grinding surface of the retaining ring has defects such as chipping or cracks, and may also analyze whether crystals have formed within the first grooves. When an abnormality occurs, an alarm alerts the operator, who then decides whether to take further action.

[0048] By adopting the above-mentioned monitoring system of the polishing head based on acoustic waves, the quality of the retaining ring on the polishing head can be monitored in real time, thereby avoiding the problem of reduced product yield due to quality problems of the retaining ring of the polishing head.

[0049] In another embodiment, the monitoring system of the polishing head based on acoustic waves is also suitable for monitoring the calibration retaining ring in the calibration polishing head, wherein the calibration polishing head includes a calibration retaining ring, and a plurality of second grooves are provided on one side of the grinding surface of the calibration retaining ring. The rotation drive unit is also suitable for driving the polishing head to rotate, so that the polishing head drives the calibration retaining ring to rotate around the central axis of the calibration retaining ring; the acoustic wave transmission liquid emitting unit is also suitable for spraying the acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring. The acoustic wave transmission liquid emitting unit and the A second liquid column is suitable for forming between the calibration retaining rings; the sound wave emitting unit is also suitable for emitting a second detection sound wave to the calibration retaining ring through the second liquid column; the sound wave receiving unit is also suitable for receiving a second feedback sound wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection sound wave; the surface morphology acquisition unit is also suitable for acquiring the calibration surface morphology of the grinding surface of the second groove and the calibration retaining ring between the second grooves according to the waveform distribution of the second detection sound wave and the second feedback sound wave; the morphology analysis unit acquires defect information of the test surface morphology according to the difference between the test surface morphology and the calibration surface morphology.

[0050] By obtaining the calibration surface topography of the ground surface of the calibration retaining ring and comparing the surface topography of the ground surface of the test retaining ring with the calibration surface topography of the ground surface of the calibration retaining ring, defect information on the ground surface of the test retaining ring can be obtained. If an abnormality occurs, an alarm will alert the operator, who will decide whether to take further action.

[0051] The acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute an acoustic test module; the monitoring system of the polishing head based on acoustic waves also includes: a test platform, on which the acoustic test module is arranged; the grinding surface of the calibration retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and the surface of the test platform is fixed; the grinding surface of the test retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the test retaining ring opposite to the grinding surface of the test retaining ring and the surface of the test platform is equal to the distance between the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring The distance between the acoustic test module and the grinding surface of the test platform is measured; the distance acquisition unit is suitable for acquiring the calibration distance between the acoustic test module and the grinding surface of the calibration retaining ring according to the time difference between the acoustic wave emitting unit emitting the second detection sound wave and the sound wave receiving unit receiving the second feedback sound wave; the distance acquisition unit is also suitable for acquiring the test distance between the acoustic test module and the grinding surface of the test retaining ring according to the time difference between the acoustic wave emitting unit emitting the first detection sound wave and the sound wave receiving unit receiving the first feedback sound wave; the wear amount acquisition unit is suitable for acquiring the wear amount of the grinding surface of the test retaining ring according to the difference between the test distance and the calibration distance.

[0052] The wear acquisition unit analyzes the wear of the retaining ring. Based on the principle of acoustic ranging, the wear acquisition unit stores the distance data between the ground surface of the retaining ring and the acoustic test module. Since the acoustic test module is stationary, the distance between the ground surface and the acoustic test module increases as the retaining ring wears. Therefore, the wear of the retaining ring is calculated by subtracting the real-time distance data from the calibrated distance data. When the wear reaches a certain level, an alarm is triggered to notify the operator whether to replace the retaining ring.

[0053] In another embodiment, it also includes: an acoustic wave transmitting unit, an acoustic wave receiving unit and an acoustic wave transmission liquid transmitting unit constitute an acoustic test module; the number of acoustic test modules is several; and the several acoustic test modules are suitable for being distributed radially along the test retaining ring during the process of the test retaining ring rotating around the central axis of the test retaining ring.

[0054] Several acoustic test modules are arranged along the radial direction of the retaining ring, which can fully receive acoustic wave feedback in scenes of different angles and depths, and compare and analyze the acoustic wave feedback obtained in different scenes, so as to obtain the surface structural morphology details of the grinding surface of the test retaining ring and the grinding surface of the calibration retaining ring, and ultimately improve the accuracy of the surface structural morphology characteristics of the grinding surface of the test retaining ring and the grinding surface of the calibration retaining ring; at the same time, the calibration distance of the calibration retaining ring and the test distance of the test retaining ring can be tested in all directions, and ultimately improve the accuracy of the calibration distance of the calibration retaining ring and the test distance of the test retaining ring.

[0055] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for monitoring a polishing head based on acoustic waves, characterized in that: include: A calibration polishing head is provided, the calibration polishing head comprising a calibration retaining ring, wherein a plurality of second grooves are provided on one side of a grinding surface of the calibration retaining ring; During the process of the calibration retaining ring rotating around the central axis of the calibration retaining ring, an acoustic wave transmission liquid emitting unit is used to spray the acoustic wave transmission liquid onto the grinding surface of the calibration retaining ring between adjacent second grooves and into the second grooves, so that a second liquid column is formed between the acoustic wave transmission liquid emitting unit and the calibration retaining ring; In the process of using the acoustic wave transmission liquid emitting unit to irradiate the polished surface of the calibration retaining ring between adjacent second grooves and spraying the acoustic wave transmission liquid into the second grooves, the acoustic wave emitting unit is used to emit a second detection acoustic wave to the calibration retaining ring through the second liquid column; A sound wave receiving unit is used to receive a second feedback sound wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection sound wave; Acquiring a calibration surface topography of the second groove and the grinding surface of the calibration retaining ring between the second grooves according to the waveform distribution of the second detection sound wave and the second feedback sound wave; A test polishing head is provided, the test polishing head comprising a test retaining ring, wherein a plurality of first grooves are provided on one side of a grinding surface of the test retaining ring; During the test retaining ring's rotation around its central axis, an acoustic wave transmission liquid emitting unit is used to spray the acoustic wave transmission liquid onto the polished surface of the test retaining ring between adjacent first grooves and into the first grooves, thereby forming a first liquid column between the acoustic wave transmission liquid emitting unit and the test retaining ring; In the process of using the acoustic wave transmission liquid emitting unit to spray the acoustic wave transmission liquid on the polished surface of the test retaining ring between adjacent first grooves and in the first grooves, the acoustic wave emitting unit is used to emit a first detection acoustic wave to the test retaining ring through the first liquid column; A sound wave receiving unit is used to receive a first feedback sound wave transmitted along the first liquid column after the test retaining ring reflects the first detection sound wave; Acquiring a test surface topography of the first groove and the polished surface of the test retaining ring between the first grooves according to the waveform distribution of the first detection sound wave and the first feedback sound wave; The step of obtaining the defect information of the test surface topography by the topography analysis unit includes: obtaining the defect information of the test surface topography by the analysis unit according to the difference between the test surface topography and the calibration surface topography; Among them, the acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute the acoustic test module; when the test retaining ring rotates around the central axis of the test retaining ring, several acoustic test modules are distributed along the radial direction of the test retaining ring.

2. The method for monitoring a polishing head based on acoustic waves according to claim 1, characterized in that: Also includes: The wear analysis unit is used to obtain the wear volume of the grinding surface of the test retaining ring.

3. The method for monitoring a polishing head based on acoustic waves according to claim 2, characterized in that: The acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute an acoustic test module; The acoustic wave-based polishing head monitoring method further includes: providing a test platform, wherein the acoustic test module is disposed on the test platform; During the process of the calibration retaining ring rotating around the central axis of the calibration retaining ring, the ground surface of the calibration retaining ring faces the test platform and the acoustic test module, and the distance between the surface of the calibration retaining ring opposite to the ground surface of the calibration retaining ring and the surface of the test platform is fixed; the calibration distance between the acoustic test module and the ground surface of the calibration retaining ring is obtained according to the time difference between the sound wave transmitting unit transmitting the second detection sound wave and the sound wave receiving unit receiving the second feedback sound wave; During the process of the test retaining ring rotating around the central axis of the test retaining ring, the grinding surface of the test retaining ring faces the test platform and the acoustic test module, and the distance from the surface of the test retaining ring opposite to the grinding surface of the test retaining ring to the surface of the test platform is equal to the distance from the surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring to the surface of the test platform; the test distance between the acoustic test module and the grinding surface of the test retaining ring is obtained according to the time difference between the sound wave transmitting unit transmitting the first detection sound wave and the sound wave receiving unit receiving the first feedback sound wave; The wear amount of the grinding surface of the test retaining ring is obtained based on the difference between the test distance and the calibration distance.

4. A monitoring system for a polishing head based on acoustic waves, for detecting a test retaining ring in a test polishing head, wherein a plurality of first grooves are provided on one side of the grinding surface of the test retaining ring, characterized in that: include: a rotation drive unit adapted to drive the test retaining ring to rotate around a central axis of the test retaining ring; an acoustic wave transmission liquid emitting unit, adapted to spray an acoustic wave transmission liquid onto the polished surface of the test retaining ring between adjacent first grooves and into the first grooves during the test retaining ring rotates about the central axis of the test retaining ring, so as to form a first liquid column between the acoustic wave transmission liquid emitting unit and the test retaining ring; an acoustic wave emitting unit, adapted to emit a first detection acoustic wave to the test retaining ring through the first liquid column; an acoustic wave receiving unit adapted to receive a first feedback acoustic wave transmitted along the first liquid column after the first detection acoustic wave is reflected by the test retaining ring; a surface topography acquisition unit adapted to acquire a test surface topography of the first groove and the grinding surface of the test retaining ring between the first grooves according to the waveform distribution of the first detection sound wave and the first feedback sound wave; A morphology analysis unit, adapted to obtain defect information of a test surface morphology; The monitoring system is also suitable for monitoring the calibration retaining ring in the calibration polishing head, the calibration polishing head includes a calibration retaining ring, and a plurality of second grooves are provided on one side of the grinding surface of the calibration retaining ring, wherein the rotation drive unit is also suitable for driving the test retaining ring to rotate around the central axis of the test retaining ring; the acoustic wave transmission liquid emitting unit is also suitable for spraying the acoustic wave transmission liquid on the grinding surface of the calibration retaining ring between adjacent second grooves and in the second grooves during the rotation of the calibration retaining ring around the central axis of the calibration retaining ring, and the acoustic wave transmission liquid emitting unit and the calibration retaining ring are suitable for forming a second groove. two liquid columns; the sound wave emitting unit is further adapted to emit a second detection sound wave to the calibration retaining ring through the second liquid column; the sound wave receiving unit is further adapted to receive a second feedback sound wave transmitted along the second liquid column after the calibration retaining ring reflects the second detection sound wave; the surface morphology acquiring unit is further adapted to acquire the calibration surface morphology of the second groove and the grinding surface of the calibration retaining ring between the second grooves according to the waveform distribution of the second detection sound wave and the second feedback sound wave; the morphology analyzing unit acquires defect information of the test surface morphology according to the difference between the test surface morphology and the calibration surface morphology; Among them, the acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute an acoustic test module; the number of acoustic test modules is several; and the several acoustic test modules are suitable for being distributed radially along the test retaining ring during the process of the test retaining ring rotating around the central axis of the test retaining ring.

5. The monitoring system for a polishing head based on acoustic waves according to claim 4, wherein the acoustic wave transmitting unit, the acoustic wave receiving unit and the acoustic wave transmission liquid transmitting unit constitute an acoustic testing module; The acoustic wave-based polishing head monitoring system further includes: a test platform, on which the acoustic test module is disposed; a grinding surface of a calibration retaining ring facing the test platform and the acoustic test module, a distance between a surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and a surface of the test platform being fixed; a grinding surface of a test retaining ring facing the test platform and the acoustic test module, a distance between a surface of the test retaining ring opposite to the grinding surface of the test retaining ring and the surface of the test platform being equal to a distance between a surface of the calibration retaining ring opposite to the grinding surface of the calibration retaining ring and the surface of the test platform; A distance acquisition unit, adapted to acquire a calibration distance between the acoustic test module and the grinding surface of the calibration retaining ring according to a time difference between the acoustic wave transmitting unit transmitting the second detection acoustic wave and the acoustic wave receiving unit receiving the second feedback acoustic wave; the distance acquisition unit is further adapted to acquire a test distance between the acoustic test module and the grinding surface of the test retaining ring according to a time difference between the acoustic wave transmitting unit transmitting the first detection acoustic wave and the acoustic wave receiving unit receiving the first feedback acoustic wave; The wear amount acquisition unit is adapted to acquire the wear amount of the grinding surface of the test retaining ring according to the difference between the test distance and the calibration distance.

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