CMP equipment polishing pad thickness real-time detection method and CMP equipment

Abstract

The invention relates to a CMP equipment polishing pad thickness real-time detection method and CMP equipment. The method for detecting the thickness of the polishing pad of the CMP equipment in real time comprises the following steps of: trimming the polishing pad by using a CMP trimmer while carrying out a CMP grinding process on a wafer; the thickness reduction amount of the polishing pad and the downward pressure value of the CMP trimmer are obtained in real time through the CMP trimmer; calculating the thickness of the polishing pad based on the thickness reduction amount of the polishing pad; and when the downward pressure value is larger than a preset downward pressure value, parameters of the CMP grinding process are adjusted, or when the thickness of the polishing pad is smaller than a preset thickness, the parameters of the CMP grinding process are adjusted. According to the method for detecting the thickness of the polishing pad of the CMP equipment in real time, the accuracy of judging the service life of the polishing pad can be improved, then the grinding quality and the yield of wafer polishing are improved, and meanwhile the polishing efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of CMP equipment, and in particular to a real-time detection method for the thickness of a polishing pad of a CMP equipment and a CMP equipment. Background Art

[0002] In the field of semiconductor manufacturing, surface planarization is an important technology for processing high-density lithography. As the only process technology that can provide global and local planarization of wafers, chemical mechanical polishing (CMP) has been widely used for the removal and planarization of interlayer dielectrics, metal layers (such as tungsten plugs, copper wiring), and shallow trench isolation. The CMP process achieves the planarization of the wafer surface through mechanical friction and chemical action between the polishing pad and the wafer. However, the thickness of the polishing pad will gradually decrease with the increase of usage time, thus affecting the polishing effect and the quality of the wafer.

[0003] At present, there are a variety of polishing pad thickness detection technologies on the market, but most of them have problems such as low detection accuracy, poor real-time performance or high cost, which leads to inaccurate polishing pad thickness monitoring, untimely replacement of polishing pads, excessive wear of polishing pads leading to degradation of polishing pad performance, reduced polishing quality and wafer yield, or early or late replacement of polishing pads leading to increased grinding costs.

[0004] Therefore, a process method is needed to detect the thickness of the polishing pad in real time, improve the accuracy of judging the service life of the polishing pad, ensure that it works in the best condition, thereby improving the grinding quality and the yield rate of wafer polishing, and at the same time improving the polishing efficiency. Summary of the invention

[0005] Therefore, the present invention provides a real-time detection method for the thickness of the polishing pad of a CMP device to solve the problems of low detection accuracy, poor real-time performance and high cost in the existing polishing pad thickness detection technology, which leads to inaccurate monitoring of the polishing pad thickness, and the degradation of the polishing pad performance due to untimely replacement of the polishing pad, thereby reducing the polishing quality and wafer yield and increasing the grinding cost.

[0006] The present invention provides a method for real-time detection of the thickness of a CMP equipment polishing pad, comprising:

[0007] While the wafer is being subjected to the CMP grinding process, the polishing pad is dressed using a CMP dresser;

[0008] Obtaining in real time through the CMP dresser a thickness reduction amount of the polishing pad and a down force value of the CMP dresser;

[0009] calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad;

[0010] When the down force value is greater than the preset down force value, the parameters of the CMP polishing process are adjusted, or:

[0011] When the thickness of the polishing pad is less than a preset thickness, the parameters of the CMP grinding process are adjusted.

[0012] Optionally, the CMP dresser is provided with a pressure bar sensor and a contact pressure sensor;

[0013] The step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time through the CMP dresser includes:

[0014] The pressure bar type sensor is used to measure the thickness reduction of the polishing pad in real time, and the contact type pressure sensor is used to measure the downward pressure value of the CMP dresser in real time.

[0015] Optionally, after the step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time, the method further includes:

[0016] Data processing is performed on the thickness reduction amount and the downforce value to obtain a thickness reduction correction value and a downforce correction value; and the correction values ​​are compared and judged with the preset downforce value and the preset thickness.

[0017] Optionally, the thickness of the polishing pad is calculated based on a thickness reduction correction value of the polishing pad;

[0018] When the downward force correction value is greater than the preset downward force value, the parameters of the CMP polishing process are adjusted, or:

[0019] When the thickness of the polishing pad is less than the preset thickness, the parameters of the CMP grinding process are adjusted.

[0020] Optionally, in the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad;

[0021] The thickness reduction includes the thickness reduction at different positions of the polishing pad. Based on the thickness reduction at different positions of the polishing pad, the thickness at different positions of the polishing pad is calculated.

[0022] Optionally, when the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process includes:

[0023] When 60% of the thicknesses at different positions are less than the preset thickness, the parameters of the CMP grinding process are adjusted.

[0024] Optionally, the method further includes:

[0025] When the thickness of the polishing pad at multiple locations is greater than a preset maximum thickness, the parameters of the CMP grinding process are adjusted.

[0026] Optionally, when the down force value is greater than a preset down force value, the step of adjusting the parameters of the CMP polishing process includes:

[0027] When the down force value is greater than the preset down force value, the CMP polishing process is stopped.

[0028] Optionally, when the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process includes:

[0029] When the thickness of the polishing pad is less than the preset thickness, stopping the CMP grinding process;

[0030] The polishing pad is replaced, and the replacement cycle of the polishing pad is recorded.

[0031] Optionally, after the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad, the method further includes:

[0032] The thickness of the polishing pad and the downforce value are displayed by a display device of the CMP device;

[0033] When the down force value is greater than the preset down force value, or when the thickness of the polishing pad is less than the preset thickness, an alarm is automatically sounded through the alarm of the CMP equipment.

[0034] Optionally, the real-time detection method for the thickness of the CMP equipment polishing pad further includes:

[0035] The parameters of the CMP conditioner are adjusted according to the down force value and the thickness of the polishing pad.

[0036] The present invention also provides a CMP device, comprising:

[0037] Polishing Pad:

[0038] A CMP dresser, located at one side of the polishing pad, and used to dress the polishing pad;

[0039] A thickness detection device is installed on the CMP dresser, and is used to measure the thickness reduction of the polishing pad and the downward pressure value of the CMP dresser in real time.

[0040] Optionally, the thickness detection device includes a pressure bar sensor and a contact pressure sensor:

[0041] The pressure rod sensor is located on the side of the cylinder pressing mechanism of the CMP dresser; the pressure rod sensor is used to measure the thickness reduction of the polishing pad in real time;

[0042] The contact pressure sensor is located on a side of the CMP dresser facing the polishing pad; the contact pressure sensor is used to measure the downward pressure value of the CMP dresser in real time.

[0043] Optionally, the CMP device further comprises: a data processing unit, configured to receive the thickness reduction amount and the downforce value acquired by the thickness detection device, perform preprocessing operations such as filtering, denoising, and calibration, and calculate the thickness of the polishing pad based on the thickness reduction amount of the polishing pad;

[0044] A display and feedback unit, comprising a display device, a feedback device and an alarm; the display device is used to show the real-time thickness of the polishing pad and the downforce value; the feedback device is used to adjust the parameters of the CMP grinding process or stop the CMP grinding process according to preset conditions; the alarm is used to automatically issue a warning according to the preset conditions;

[0045] A data storage unit, used to store data acquired by the thickness detection device, data of the data processing unit and replacement cycle data of the polishing pad;

[0046] The grinding unit comprises a grinding head, and the grinding unit is used for performing a CMP grinding process on a wafer.

[0047] The technical solution of the present invention has the following advantages:

[0048] (1) The real-time detection method of the thickness of the polishing pad of the CMP equipment provided by the present invention, on the one hand, can accurately grasp the consumption of the polishing pad by real-time detection of the thickness of the polishing pad and the downward pressure value of the CMP dresser, thereby accurately judging its service life, which helps to timely replace the polishing pad or adjust the parameters of the CMP grinding process before the performance of the polishing pad decreases, avoid the degradation of the polishing quality caused by excessive wear of the polishing pad, and improve the grinding quality and the yield rate of wafer polishing. At the same time, it can also avoid replacing the polishing pad too early or too late, and reduce unnecessary grinding costs. On the other hand, the detection of the thickness of the polishing pad by the CMP dresser can be carried out synchronously with the production process of the CMP grinding process without interrupting production, thereby effectively protecting production capacity and improving production efficiency. Therefore, the real-time detection method of the thickness of the polishing pad of the CMP equipment provided by the present invention can improve the accuracy of judging the service life of the polishing pad, thereby improving the grinding quality and the yield rate of wafer polishing, and at the same time improving the polishing efficiency.

[0049] (2) The present invention provides a method for real-time detection of the thickness of the polishing pad of a CMP device. The pressure rod sensor is used to measure the thickness reduction of the polishing pad in real time, and the contact pressure sensor is used to measure the downward pressure value of the CMP dresser in real time. The thickness of the polishing pad and the downward pressure value of the CMP dresser can be accurately measured, so as to more accurately grasp the consumption of the polishing pad, thereby achieving timely replacement of the polishing pad or adjustment of the parameters of the CMP grinding process before the performance of the polishing pad deteriorates, avoiding the degradation of polishing quality due to excessive wear of the polishing pad, and improving the grinding quality and the yield rate of wafer polishing.

[0050] (3) The present invention provides a real-time detection method for the thickness of the polishing pad of a CMP device. The thickness of the polishing pad and the downward pressure value are detected by a CMP dresser. The parameters of the CMP dresser can be adjusted in time according to the data of the thickness of the polishing pad and the downward pressure value, so as to better control the morphology of the polishing pad and ensure that the polishing pad remains in the best state during the grinding process, thereby improving the grinding quality and the flatness of the wafer.

[0051] (4) The CMP equipment provided by the present invention can realize automatic real-time detection of the thickness of the polishing pad, saving a lot of manpower costs; and can improve the accuracy of judging the service life of the polishing pad, so that the polishing pad can be replaced in time or the parameters of the CMP grinding process can be adjusted before the performance of the polishing pad decreases, thereby improving the grinding quality and the yield rate of wafer polishing, and avoiding replacing the polishing pad too early or too late, thereby reducing unnecessary grinding costs; at the same time, the thickness of the polishing pad can be detected in real time during the CMP grinding process production process without interrupting production, thereby effectively protecting production capacity and improving production efficiency.

[0052] (5) The CMP equipment provided by the present invention, the high-precision sensor, data processing unit, display and feedback unit, data storage unit and other modules in the thickness detection device work together to achieve real-time, accurate monitoring and automatic adjustment of the thickness of the polishing pad, so that the polishing pad is kept in good condition, and defects and damage during the grinding process are reduced, thereby improving production efficiency, ensuring product quality, and reducing maintenance costs. In addition, it can also achieve automated and intelligent production and deal with technical issues such as changes in the polishing pad during use, which is helpful to improve the overall efficiency and product quality of the semiconductor manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic flow chart of a method for real-time detection of the thickness of a polishing pad of a CMP device according to an embodiment of the present invention;

[0055] Figure 2 A schematic flow chart of a method for determining the quality of a polishing pad based on the thickness of the polishing pad at different positions according to an embodiment of the present invention;

[0056] Figure 3 A schematic diagram of a specific process of a method for real-time detection of the thickness of a polishing pad of a CMP device according to an embodiment of the present invention;

[0057] Figure 4 A schematic diagram of the structure of a CMP device according to an embodiment of the present invention;

[0058] Figure 5 The figure is a schematic diagram of the specific structure of a CMP device according to an embodiment of the present invention.

[0059] Description of reference numerals:

[0060] 10-polishing pad; 20-CMP dresser; 21-thickness detection device; 30-data processing unit; 40-display and feedback unit; 50-data storage unit; 60-grinding unit. DETAILED DESCRIPTION

[0061] In the prior art, one method of measuring the thickness of the polishing pad is to obtain the distance between the laser ranging sensor probe and the upper and lower surfaces of the measuring wafer in real time through a laser ranging sensor. And to perform auxiliary measurement through an eddy current ranging sensor. However, this solution has the following disadvantages:

[0062] First, laser ranging sensors have the following disadvantages: ① The measurement accuracy is affected by the environment: The accuracy of laser ranging sensors may be affected by factors such as temperature, humidity, air pressure and air cleanliness in the measurement environment. For example, dust, water mist and other particles in the air may scatter the laser beam, causing the measurement signal to attenuate, thereby affecting the measurement accuracy. In addition, the smoothness, color and reflection characteristics of the measurement surface will also affect the accuracy of laser ranging. ② Measurement range limitation: Laser ranging sensors usually have certain measurement range limitations. For targets beyond their measurement range, the sensor may not be able to measure accurately or cannot measure. This limits its application in certain specific scenarios. ③ High installation and calibration requirements: The installation position and angle of the laser ranging sensor have an important influence on its measurement results. Therefore, it is necessary to ensure the accurate alignment and calibration of the sensor during the installation process to avoid measurement errors caused by improper installation. At the same time, regular calibration and maintenance are also the key to ensuring measurement accuracy.

[0063] Second, eddy current distance sensors have the following disadvantages: ① Material dependence: Eddy current sensors mainly measure distance by inducing the eddy current effect of metal materials through magnetic fields. Therefore, its measurement accuracy is highly dependent on the conductivity of the material being measured. For metal or non-metal materials with poor conductivity, the measurement effect of eddy current sensors may be significantly affected. This means that the applicability of eddy current sensors is limited when measuring non-metallic materials or metal materials with poor conductivity. ② Measurement depth limitation: The measurement depth of eddy current sensors is usually affected by the sensor model, parameter settings, and the characteristics of the material being measured. For thicker materials or materials with complex internal structures, the sensor may not be able to accurately measure their internal distance or shape. ③ Environmental interference: Eddy current sensors may be interfered with by surrounding electromagnetic fields during operation, such as electromagnetic radiation from equipment such as motors and transformers. These interference signals may be superimposed on the measurement signal, resulting in increased errors in the measurement results.

[0064] Third, the disadvantages of combining laser ranging sensors and eddy current ranging sensors: ① Although the combined use of laser ranging sensors and eddy current ranging sensors can improve the accuracy and stability of measurement, it also increases the complexity and cost of the system. In addition, the maintenance and management of the two sensors also require additional manpower and material resources. ② Data processing and algorithm complexity: Due to the use of indirect measurement methods, the data of laser ranging sensors and eddy current ranging sensors need to be processed by algorithms to obtain the final measurement results. This requires the algorithm to have high complexity and accuracy to ensure the reliability of the measurement results. However, complex algorithms may also increase computing time and resource consumption.

[0065] In order to solve the problems of low detection accuracy, poor real-time performance and high cost in the existing polishing pad thickness detection technology, which leads to inaccurate monitoring of the polishing pad thickness, degradation of the polishing pad performance due to untimely replacement of the polishing pad, and further reduction of polishing quality and wafer yield, and increase in grinding cost, the present invention provides a real-time detection method for the thickness of a CMP device polishing pad, comprising the following steps: while performing a CMP grinding process on a wafer, trimming the polishing pad by a CMP dresser; obtaining in real time the thickness reduction amount of the polishing pad and the down force value of the CMP dresser by the CMP dresser; calculating the thickness of the polishing pad based on the thickness reduction amount of the polishing pad; and adjusting the parameters of the CMP grinding process when the down force value is greater than a preset down force value, or: adjusting the parameters of the CMP grinding process when the thickness of the polishing pad is less than a preset thickness.

[0066] The present invention also provides a CMP device, comprising: a polishing pad; a CMP dresser, located on one side of the polishing pad, the CMP dresser being used to dress the polishing pad; a thickness detection device, installed on the CMP dresser, the thickness detection device being used to measure in real time the thickness reduction of the polishing pad and the downward pressure value of the CMP dresser.

[0067] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0068] Example 1

[0069] refer to Figure 1 This embodiment provides a real-time detection method for the thickness of a polishing pad of a CMP device, comprising:

[0070] S101, while performing a CMP grinding process on the wafer, using a CMP dresser to dress the polishing pad;

[0071] S102, obtaining in real time through the CMP dresser a thickness reduction amount of the polishing pad and a down force value of the CMP dresser;

[0072] S103, calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad;

[0073] S104, when the down force value is greater than a preset down force value, adjusting the parameters of the CMP polishing process, or:

[0074] When the thickness of the polishing pad is less than a preset thickness, the parameters of the CMP grinding process are adjusted.

[0075] In the CMP process, the pressure value of the CMP dresser (Disk) is a key process parameter. If the actual pressure value exceeds the preset pressure value, it means that other parameters of the grinding process (such as grinding speed, grinding liquid flow rate, etc.) need to be adjusted to maintain the stability and consistency of the grinding effect. The pressure value directly affects the polishing rate, polishing uniformity and wafer surface quality. If the pressure value is not appropriate, it may cause insufficient or excessive polishing, thus affecting the performance and yield of the wafer. Therefore, it is very important to accurately detect and control the pressure value of the Disk. The pressure value indirectly affects the wear rate and polishing effect of the polishing pad by affecting the contact area and contact pressure between the Disk and the polishing pad. Generally speaking, a larger pressure value will accelerate the wear of the polishing pad and may cause the surface of the polishing pad to become rougher, thus affecting the polishing quality. At the same time, the thickness and quality of the polishing pad will also affect its ability to withstand pressure and its service life. If the polishing pad is too thin or of poor quality, it may not be able to withstand the normal pressure value, resulting in early failure. If the thickness of the polishing pad decreases below the preset thickness, it indicates that the polishing pad has been worn to a certain extent and needs to be replaced or the parameters of the grinding process adjusted (such as increasing the down force, replacing a rougher polishing pad, etc.) to maintain the grinding efficiency. Therefore, by real-time monitoring of the thickness of the polishing pad and the down force value of the CMP dresser, the polishing pad can be replaced in time and the parameters of the CMP grinding process can be adjusted, thereby improving the grinding quality and the yield rate of wafer polishing.

[0076] During specific implementation, the specific values ​​of the preset downward pressure value and the preset thickness can be set according to actual needs, and this embodiment does not limit this.

[0077] The real-time detection method for the thickness of the polishing pad of the CMP equipment provided in this embodiment, on the one hand, can accurately grasp the consumption of the polishing pad by real-time detection of the thickness of the polishing pad and the downward pressure value of the CMP dresser, thereby accurately judging its service life, which helps to timely replace the polishing pad or adjust the parameters of the CMP grinding process before the performance of the polishing pad decreases, avoid the degradation of the polishing quality caused by excessive wear of the polishing pad, and improve the grinding quality and the yield rate of wafer polishing. At the same time, it can also avoid replacing the polishing pad too early or too late, and reduce unnecessary grinding costs. On the other hand, by detecting the thickness of the polishing pad through the CMP dresser, it can be synchronized with the production process of the CMP grinding process without interrupting production, thereby effectively protecting production capacity and improving production efficiency. Therefore, the real-time detection method for the thickness of the polishing pad of the CMP equipment provided by the present invention can improve the accuracy of judging the service life of the polishing pad, thereby improving the grinding quality and the yield rate of wafer polishing, and at the same time improving the polishing efficiency.

[0078] Further, in some embodiments, the CMP conditioner is provided with a pressure bar sensor and a contact pressure sensor;

[0079] The step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time through the CMP dresser includes:

[0080] The pressure bar type sensor is used to measure the thickness reduction of the polishing pad in real time, and the contact type pressure sensor is used to measure the downward pressure value of the CMP dresser in real time.

[0081] In the prior art, laser sensors are generally used to measure the thickness of the polishing pad. In actual use, laser sensors have low sealing and are easily damaged. In addition, the environment during the CMP polishing process is acidic and alkaline, and it is easy to splash water. The installation position and angle of the laser sensor have a great influence on its measurement, and the assembly is difficult. In addition, the thickness reduction of the polishing pad per unit time is about 0.6mm / 35h=0.017mm / h, and the zero point offset error of the laser sensor is 0.03mm, which is relatively large, and it is impossible to accurately measure the thickness reduction of the polishing pad.

[0082] This solution uses a pressure rod type sensor, which has the following advantages: the pressure rod type sensor is mainly a mechanical structure that is not affected by splashing water; the pressure rod type is less difficult to assemble; since the thickness reduction of the polishing pad per unit time is approximately 0.6mm / 35h=0.017mm / h, and the zero point offset error of the pressure rod type sensor is 0.016mm, which is smaller than that of the laser sensor, the thickness reduction of the polishing pad can be accurately measured.

[0083] In specific implementation, when the CMP grinding process is started, the CMP dresser starts working, the cylinder of the CMP dresser (disk) is pressed down, the spline shaft drives the disk assembly to press down and rotate, the disk assembly contacts the polishing pad for grinding, and the thickness of the polishing pad is gradually reduced. During this process, the contact pressure sensor will feedback the pressure value in real time; the pressure rod sensor will feedback the thickness reduction of the polishing pad in real time. These data are converted into processable digital signals through the conversion mechanism inside the sensor.

[0084] The real-time detection method for the thickness of the polishing pad of a CMP device provided in this embodiment uses the pressure rod sensor to measure the thickness reduction of the polishing pad in real time, and uses the contact pressure sensor to measure the downward pressure value of the CMP dresser in real time. The thickness of the polishing pad and the downward pressure value of the CMP dresser can be accurately measured, so as to more accurately grasp the consumption of the polishing pad, thereby achieving timely replacement of the polishing pad or adjustment of the parameters of the CMP grinding process before the performance of the polishing pad deteriorates, avoiding the degradation of polishing quality due to excessive wear of the polishing pad, and improving the grinding quality and the yield rate of wafer polishing.

[0085] Furthermore, in some embodiments, after the step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time, the step further includes:

[0086] Data processing is performed on the thickness reduction amount and the downforce value to obtain a thickness reduction correction value and a downforce correction value; and the correction values ​​are compared and judged with the preset downforce value and the preset thickness.

[0087] Further, in some embodiments, the thickness of the polishing pad is calculated based on the thickness thinning correction value of the polishing pad;

[0088] When the downward force correction value is greater than the preset downward force value, the parameters of the CMP polishing process are adjusted, or:

[0089] When the thickness of the polishing pad is less than the preset thickness, the parameters of the CMP grinding process are adjusted.

[0090] In specific implementation, the data such as the thickness reduction amount and the pressure value collected are input into a data processing unit (such as a microprocessor, PLC or computer) through a data processing unit of a CMP device, and pre-processing operations such as filtering, denoising and calibration are performed to improve the accuracy and reliability of the data, and obtain a thickness reduction correction value and a pressure correction value. Subsequently, the thickness of the polishing pad is calculated based on the thickness reduction correction value of the polishing pad through an algorithm, which usually involves comparison with the initial thickness or standard thickness, and possible linear or nonlinear compensation.

[0091] Further, in some embodiments, in the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad;

[0092] The thickness reduction includes the thickness reduction at different positions of the polishing pad. Based on the thickness reduction at different positions of the polishing pad, the thickness at different positions of the polishing pad is calculated.

[0093] Further, in some embodiments, when the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process includes:

[0094] When 60% of the thicknesses at different positions are less than the preset thickness, the parameters of the CMP grinding process are adjusted.

[0095] In practice, since the wear of the polishing pad is usually uneven, multiple representative locations should be selected for measurement when measuring thickness, and the thickness values ​​of these locations should be considered comprehensively. If 60% of the thickness of most or key locations is lower than the preset thickness, such as 20μm, it is particularly necessary to adjust the parameters of the CMP grinding process.

[0096] Furthermore, in some embodiments, the method further comprises:

[0097] When the thickness of the polishing pad at multiple locations is greater than a preset maximum thickness, the parameters of the CMP grinding process are adjusted.

[0098] In a specific implementation, whether the polishing pad meets the standard is judged based on the thickness of different positions of the polishing pad obtained by calculation. Figure 2 The figure is a flow chart of a method for judging the quality of a polishing pad based on the thickness of the polishing pad at different positions.

[0099] S201, formulate a preset thickness standard for the polishing pad based on the use requirements of the polishing pad, process parameters, equipment performance, etc. This standard usually includes the minimum thickness, maximum thickness, and allowable thickness deviation range of the polishing pad.

[0100] S202, point-by-point comparison: comparing the thickness data of each position of the polishing pad with a preset thickness standard to determine whether the thickness of each position meets the standard requirement.

[0101] S203, comprehensive analysis: If the thickness of most positions on the polishing pad (proportion greater than 60%) is close to or lower than the preset minimum thickness, or the thickness of multiple positions exceeds the preset maximum thickness, or the thickness deviation range is too large, then it can be considered that the polishing pad has reached the standard for replacement.

[0102] S204, generating topography data: Based on the thickness detection results at multiple locations, topography data of the polishing pad can be generated, which helps to more intuitively understand the wear of the polishing pad. By comparing the topography data with the preset topography standard, it can also assist in determining whether the polishing pad needs to be replaced.

[0103] Further, in some embodiments, when the down force value is greater than a preset down force value, the step of adjusting the parameters of the CMP polishing process includes:

[0104] When the down force value is greater than the preset down force value, the CMP polishing process is stopped.

[0105] In specific implementation, when the pressure value is greater than the preset pressure value, the CMP polishing process is stopped. Then the pressure value is detected by the instrument, and other parameters of the subsequent polishing process (such as polishing speed, polishing liquid flow, etc.) are adjusted according to the actual situation; and the polishing pad is checked, and the staff determines whether the polishing pad needs to be replaced according to the actual situation.

[0106] Further, in some embodiments, when the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process includes:

[0107] When the thickness of the polishing pad is less than the preset thickness, stopping the CMP grinding process;

[0108] The polishing pad is replaced, and the replacement cycle of the polishing pad is recorded.

[0109] In specific implementation, the data storage unit of the polishing equipment records the replacement cycle data of the polishing pad, and also stores the data such as the thickness and pressure value of the polishing pad in the data storage unit for subsequent data analysis, trend prediction or fault diagnosis. Through long-term data accumulation, the polishing process parameters can be optimized to improve production efficiency and product quality.

[0110] Furthermore, in some embodiments, after the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad, the method further includes:

[0111] The thickness of the polishing pad and the downforce value are displayed by a display device of the CMP device;

[0112] When the down force value is greater than the preset down force value, or when the thickness of the polishing pad is less than the preset thickness, an alarm is automatically sounded through the alarm of the CMP equipment.

[0113] In specific implementation, the calculated polishing pad thickness and downforce value are displayed in real time on the display device of the CMP equipment for operator monitoring. At the same time, according to the preset threshold or condition, the display and feedback unit can automatically issue a warning or adjust the polishing parameters (such as pressure, speed, acceleration, etc.) to prevent damage or degradation of polishing quality caused by the polishing pad being too thin.

[0114] Furthermore, in some embodiments, the real-time detection method of the thickness of the polishing pad of the CMP equipment further includes:

[0115] The parameters of the CMP conditioner are adjusted according to the down force value and the thickness of the polishing pad.

[0116] The real-time detection method for the thickness of the polishing pad of a CMP device provided in this embodiment detects the thickness of the polishing pad and the downward pressure value through a CMP dresser, and can also timely adjust the parameters of the CMP dresser according to the data of the thickness of the polishing pad and the downward pressure value, so as to better control the morphology of the polishing pad and ensure that the polishing pad remains in the best state during the grinding process, thereby improving the grinding quality and the flatness of the wafer.

[0117] In a specific example, a specific flow chart of a method for real-time detection of the thickness of a CMP device polishing pad is as follows: Figure 3 shown.

[0118] S301, selecting parameters of the CMP polishing process.

[0119] S302, entering the grinding process; using a CMP dresser to dress the polishing pad.

[0120] S303, the cylinder of the CMP dresser is pressed down; the spline shaft drives the Disk assembly to be pressed down and rotated.

[0121] S304: The contact pressure sensor feeds back the downward pressure value in real time, and then executes steps S305 and S306.

[0122] S305, determining whether the downforce value is greater than a preset downforce value. If yes, executing step S305-1; if no, executing step S305-2.

[0123] S305-1, sound an alarm and terminate the CMP polishing process.

[0124] S305-2, continue to perform the CMP polishing process.

[0125] S306, the pressure rod sensor feeds back the thickness reduction in real time.

[0126] S307, calculating the thickness of the polishing pad based on the thickness reduction amount.

[0127] S308, determining whether the thickness of the polishing pad is less than a preset thickness. If yes, executing step S308-1; if no, executing step S308-2.

[0128] S308-1, sound an alarm, terminate the CMP grinding process, and provide feedback on the replacement cycle of the polishing pad.

[0129] S308-2, continue to execute the CMP grinding process; and feedback the replacement cycle of the polishing pad.

[0130] Example 2

[0131] refer to Figure 4 The present invention also provides a CMP device, comprising:

[0132] Polishing Pad 10:

[0133] A CMP dresser 20, located at one side of the polishing pad 100, and the CMP dresser 20 is used to dress the polishing pad 10;

[0134] The thickness detection device 21 is installed on the CMP dresser 20 . The thickness detection device 21 is used to measure the thickness reduction of the polishing pad 10 and the downward pressure value of the CMP dresser 20 in real time.

[0135] The CMP equipment provided in this embodiment can realize automatic real-time detection of the thickness of the polishing pad, saving a lot of manpower costs; and can improve the accuracy of judging the service life of the polishing pad, so that the polishing pad can be replaced in time or the parameters of the CMP grinding process can be adjusted before the performance of the polishing pad deteriorates, thereby improving the grinding quality and the yield rate of wafer polishing, and avoiding replacing the polishing pad too early or too late, reducing unnecessary grinding costs; at the same time, the thickness of the polishing pad can be detected in real time during the CMP grinding process production process without interrupting production, thereby effectively protecting production capacity and improving production efficiency.

[0136] Furthermore, in some embodiments, the thickness detection device 21 includes a pressure bar sensor and a contact pressure sensor:

[0137] The pressure rod sensor is located on the side of the cylinder pressing mechanism of the CMP dresser; the pressure rod sensor is used to measure the thickness reduction of the polishing pad 10 in real time;

[0138] The contact pressure sensor is located at a side of the CMP dresser 20 facing the polishing pad 10 ; the contact pressure sensor is used to measure the downward pressure value of the CMP dresser 20 in real time.

[0139] Furthermore, in some embodiments, Figure 5 As shown, the CMP device also includes:

[0140] a data processing unit 30, configured to receive the thickness reduction amount and the downforce value obtained by the thickness detection device 21, perform preprocessing operations such as filtering, denoising, and calibration, and calculate the thickness of the polishing pad based on the thickness reduction amount of the polishing pad;

[0141] The display and feedback unit 40 includes a display device, a feedback device and an alarm; the display device is used to show the real-time thickness of the polishing pad and the downforce value; the feedback device is used to adjust the parameters of the CMP polishing process or stop the CMP polishing process according to preset conditions; the alarm is used to automatically issue a warning according to preset conditions;

[0142] A data storage unit 50, used to store data acquired by the thickness detection device 21, data of the data processing unit 30 and replacement cycle data of the polishing pad 10;

[0143] The grinding unit 60 includes a grinding head, and the grinding unit 60 is used to perform a CMP grinding process on the wafer.

[0144] In a specific implementation, the grinding unit 60 further includes components such as a carrier plate, and the CMP dresser 20 further includes components such as a dresser swing arm.

[0145] The CMP equipment provided by the present invention mainly includes the steps of data acquisition, data processing, real-time display and feedback, and data storage and analysis when implementing the real-time detection method of polishing pad thickness.

[0146] First, the thickness detection device is used for data collection. The parameters of the CMP grinding process are selected and the CMP process is started. During the grinding process, the CMP dresser dresses the polishing pad. The sensor begins to collect the down pressure value of the CMP dresser in real time through the contact pressure sensor, and the pressure rod sensor begins to collect the thickness change data of the polishing pad surface in real time. These data are converted into processable digital signals through the conversion mechanism inside the sensor.

[0147] Secondly, the data is processed using a data processing unit. The collected data is input into a data processing unit (such as a microprocessor, PLC or computer) for pre-processing operations such as filtering, denoising, and calibration to improve the accuracy and reliability of the data. Subsequently, the current thickness of the polishing pad is calculated by an algorithm. This usually involves a comparison with the initial thickness or standard thickness, and possible linear or nonlinear compensation.

[0148] Thirdly, the display and feedback unit is used for real-time display and feedback: the calculated polishing pad thickness and the down force value of the CMP dresser are displayed in real time on the operation interface for the operator to monitor. At the same time, according to the preset threshold or condition, the display and feedback unit can automatically issue a warning or adjust the polishing parameters (such as pressure, speed, acceleration, etc.) to prevent damage or degradation of polishing quality caused by the polishing pad being too thin.

[0149] Finally, the data storage unit is used to store and analyze data: the data and analysis results of each test are stored in the database for subsequent data analysis, trend prediction or fault diagnosis. Through long-term data accumulation, polishing process parameters can be optimized to improve production efficiency and product quality.

[0150] The CMP equipment provided by the present invention realizes real-time and accurate monitoring and automatic adjustment of the thickness of the polishing pad through the coordinated work of modules such as the high-precision sensor, data processing unit, display and feedback unit, and data storage unit in the thickness detection device, so that the polishing pad is kept in a good state, and defects and damages in the grinding process are reduced, thereby improving production efficiency, ensuring product quality, and reducing maintenance costs. In addition, it can also realize automated and intelligent production and deal with technical problems such as changes in the polishing pad during use, which is helpful to improve the overall efficiency and product quality of the semiconductor manufacturing industry.

[0151] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A real-time detection method for the thickness of a CMP equipment polishing pad, characterized in that: include: While the wafer is being subjected to the CMP grinding process, the polishing pad is dressed using a CMP dresser; Obtaining in real time through the CMP dresser a thickness reduction amount of the polishing pad and a down force value of the CMP dresser; calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad; When the down force value is greater than the preset down force value, the parameters of the CMP polishing process are adjusted, or: When the thickness of the polishing pad is less than a preset thickness, the parameters of the CMP grinding process are adjusted.

2. The real-time detection method for the thickness of the polishing pad of a CMP device according to claim 1, characterized in that: The CMP dresser is provided with a pressure bar sensor and a contact pressure sensor; The step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time through the CMP dresser includes: The pressure bar type sensor is used to measure the thickness reduction of the polishing pad in real time, and the contact type pressure sensor is used to measure the downward pressure value of the CMP dresser in real time.

3. The real-time detection method for the thickness of the polishing pad of a CMP device according to claim 2, characterized in that: After the step of obtaining the thickness reduction of the polishing pad and the down force value of the CMP dresser in real time, the method further includes: Data processing is performed on the thickness reduction amount and the downforce value to obtain a thickness reduction correction value and a downforce correction value; and the correction values ​​are compared and judged with the preset downforce value and the preset thickness.

4. The real-time detection method for the thickness of the polishing pad of a CMP device according to claim 3, characterized in that: calculating the thickness of the polishing pad based on the thickness reduction correction value of the polishing pad; When the downward force correction value is greater than the preset downward force value, the parameters of the CMP polishing process are adjusted, or: When the thickness of the polishing pad is less than the preset thickness, the parameters of the CMP grinding process are adjusted.

5. The method for real-time detection of polishing pad thickness according to claim 1, characterized in that: In the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad; The thickness reduction includes the thickness reduction at different positions of the polishing pad. Based on the thickness reduction at different positions of the polishing pad, the thickness at different positions of the polishing pad is calculated.

6. The real-time detection method for the thickness of the polishing pad of a CMP device according to claim 5, characterized in that: When the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process comprises: When 60% of the thicknesses at different positions are less than the preset thickness, the parameters of the CMP grinding process are adjusted.

7. The method for real-time detection of polishing pad thickness according to claim 6, characterized in that: The method further comprises: When the thickness of the polishing pad at multiple locations is greater than a preset maximum thickness, the parameters of the CMP grinding process are adjusted.

8. The real-time detection method for the thickness of the polishing pad of a CMP device according to claim 1, characterized in that: When the down force value is greater than a preset down force value, the step of adjusting the parameters of the CMP polishing process includes: When the down force value is greater than the preset down force value, the CMP polishing process is stopped.

9. The method for real-time detection of polishing pad thickness according to claim 8, characterized in that: When the thickness of the polishing pad is less than a preset thickness, the step of adjusting the parameters of the CMP grinding process comprises: When the thickness of the polishing pad is less than the preset thickness, stopping the CMP grinding process; The polishing pad is replaced, and the replacement cycle of the polishing pad is recorded.

10. The real-time detection method of the polishing pad thickness of a CMP equipment according to claim 1, characterized in that: After the step of calculating the thickness of the polishing pad based on the thickness reduction of the polishing pad, the method further includes: The thickness of the polishing pad and the downforce value are displayed by a display device of the CMP device; When the down force value is greater than the preset down force value, or when the thickness of the polishing pad is less than the preset thickness, an alarm is automatically sounded through the alarm of the CMP equipment.

11. The real-time detection method of the polishing pad thickness of a CMP device according to claim 1, characterized in that: The real-time detection method for the thickness of the CMP equipment polishing pad also includes: The parameters of the CMP conditioner are adjusted according to the down force value and the thickness of the polishing pad.

12. A CMP device, characterized in that: include: Polishing Pad: A CMP dresser, located at one side of the polishing pad, and used to dress the polishing pad; A thickness detection device is installed on the CMP dresser, and is used to measure the thickness reduction of the polishing pad and the downward pressure value of the CMP dresser in real time.

13. The CMP apparatus according to claim 12, characterized in that: The thickness detection device includes a pressure bar sensor and a contact pressure sensor: The pressure rod sensor is located on the side of the cylinder pressing mechanism of the CMP dresser; the pressure rod sensor is used to measure the thickness reduction of the polishing pad in real time; The contact pressure sensor is located on a side of the CMP dresser facing the polishing pad; the contact pressure sensor is used to measure the downward pressure value of the CMP dresser in real time.

14. The CMP apparatus according to claim 12, characterized in that: The CMP device also includes: a data processing unit, configured to receive the thickness reduction amount and the downforce value acquired by the thickness detection device, perform preprocessing operations such as filtering, denoising, and calibration, and calculate the thickness of the polishing pad based on the thickness reduction amount of the polishing pad; A display and feedback unit, comprising a display device, a feedback device and an alarm; the display device is used to show the real-time thickness of the polishing pad and the downforce value; the feedback device is used to adjust the parameters of the CMP grinding process or stop the CMP grinding process according to preset conditions; the alarm is used to automatically issue a warning according to the preset conditions; A data storage unit, used to store data acquired by the thickness detection device, data of the data processing unit and replacement cycle data of the polishing pad; The grinding unit comprises a grinding head, and the grinding unit is used for performing a CMP grinding process on a wafer.

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