Polishing pad groove depth detection method

Abstract

The present invention provides a method for detecting the groove depth of a polishing pad. The polishing pad detection method of the present invention obtains the actual depth of the polishing pad in a CMP system by setting a marking light, obtaining the sine value of the calculated angle, obtaining a detection image, and calculating a formula. The polishing pad depth detection method of the present invention can solve the problems of low efficiency, easy surface damage and large error in manually measuring the groove depth of the polishing pad during shutdown. The actual depth obtained by real-time measurement can provide a parameter basis for the polishing process and optimize the polishing process parameters.

Description

Technical Field

[0001] The invention relates to the technical field of chemical mechanical planarization, and in particular to a method for detecting the depth of a polishing pad groove. Background Art

[0002] With the development of Moore's Law, the role of chemical mechanical planarization (CMP) in the semiconductor process is becoming more and more important. As a key consumable in the CMP process, the morphology of the polishing pad is crucial to the polishing effect of the wafer, and the groove depth will also affect the polishing efficiency of the wafer. The polishing pad is an important part of the CMP system, with functions such as storing and transporting polishing liquid, discharging polishing process products, and maintaining the mechanical and chemical environment required for the process. Therefore, the performance of the polishing pad will affect the processing efficiency and quality in the CMP process. The morphology of the polishing pad has a significant impact on the processing process. Common polishing pad surface morphologies include grooves, annular grooves, square grooves, involute grooves, etc., among which the most common is the annular groove. During the processing process, the groove is filled with a mixture of polishing liquid and polishing process products. Under the mechanical friction between the wafer and the dresser, the groove depth of the polishing pad will continue to decrease. When the groove depth is reduced to a certain extent, it will seriously affect the polishing efficiency and quality. Replacing the polishing pad too early will cause waste of consumables; replacing it too late will affect the processing quality and efficiency of the wafer. Therefore, it is necessary to regularly measure and monitor the groove depth of the polishing pad to ensure that it can be replaced in time. In the prior art, it is usually necessary to shut down the CMP system to measure the groove depth of the polishing pad. After the CMP system is shut down, the groove depth is measured manually, which is complicated and inefficient. There is a high probability that the surface morphology of the polishing pad will be damaged during the measurement process; and the measurement data is manually read, which has large errors. Therefore, a solution is needed to solve the problem that manual measurement of the groove depth of the polishing pad is inefficient, easy to cause surface damage and large errors. Summary of the invention

[0003] The invention provides a polishing pad groove depth detection method to solve the problems of low efficiency, easy surface damage and large error in manually measuring the polishing pad groove depth during shutdown.

[0004] The invention provides a method for detecting the depth of a polishing pad groove, comprising the following steps: providing a CMP system and a polishing pad; setting a marking light, projecting the marking light onto the groove of the polishing pad through an optical module, the marking light spanning the width direction of the groove; defining the portion of the marking light on the surface of the polishing pad as a first marking light, and defining the portion of the marking light at the bottom of the groove as a second marking light; acquiring a detection image, after the CMP system runs for a period of time, photographing the polishing pad through a camera module arranged above the side of the polishing pad to acquire a detection image; measuring the spacing length between the first marking light and the second marking light at this time, defining the length as a detection length; acquiring the sine value of a calculated angle, defining a line from a horizontal line where the camera module is located to an intersection point of the second marking light and a side wall of the groove of the polishing pad away from the camera module as a first measurement line, and defining a line from the camera module to an intersection point of the second marking light and the side wall of the groove as a second measurement line; defining the angle between the second measurement line and the first measurement line as a calculated angle, and obtaining the sine value of the calculated angle through the installation position of the camera module; at this time, the actual depth of the groove is calculated by the following formula:

[0005] H m =L m ÷Sin∠α

[0006] In the formula, H m is the actual depth of the groove; L m is the detection length in the detection image; Sin∠α is the sine value of the calculated angle.

[0007] Optionally, in the step of acquiring a detection image, the acquired detection image includes at least the bottom of the groove on the side away from the camera module; the detection length is the distance between the endpoint of the second marking light at the bottom of the groove on that side and the endpoint of the first marking light closest to the bottom of the groove on that side.

[0008] Optionally, the sine value of the angle is calculated using the following formula.

[0009] Cos∠α=L c ÷L b

[0010] (Sin∠α) 2 +(Cos∠α) 2 =1

[0011] Where Cos∠α is the cosine value of the angle to be calculated; L b is the length of the second measuring line; L c is the length of the first measurement line.

[0012] Optionally, the actual depth of the groove is calculated by a data processing module in the CMP system, and the data processing module is connected to the camera module to obtain a detection image; the calculated angle is input and set after the calculation.

[0013] The present invention also provides another method for detecting the depth of a polishing pad groove, comprising the following steps: providing a CMP system and a polishing pad; obtaining a detection image of the polishing pad by means of a camera module disposed above the side of the polishing pad in the CMP system; providing a comparison scale, the comparison scale being a scale of the actual height of the groove of the polishing pad in the detection image and the visual length of the groove of the polishing pad in the detection image, and obtaining the actual height of the groove by reading the comparison scale.

[0014] Optionally, the comparison scale is obtained by the following steps: providing a CMP system and a sample polishing pad; setting a marking light, projecting the marking light to the groove of the sample polishing pad through an optical module, the marking light spanning the width direction of the groove; defining the portion of the marking light on the surface of the sample polishing pad as a first marking light, and defining the portion of the marking light at the bottom of the groove as a second marking light; obtaining the sine value of the calculated angle, defining a line from a horizontal line where the camera module is located to the intersection of the second marking light and the side wall of the groove of the sample polishing pad away from the camera module as a first measuring line, and defining a line from the camera module to the second marking light as a line extending from the .... The line connecting the intersection of the light and the side wall of the groove is recorded as the second measurement line; the angle between the second measurement line and the first measurement line is defined as the calculated angle, and the sine value of the calculated angle is obtained by the installation position of the camera module; a detection image group is obtained, and after the CMP system is run, the polishing pad is photographed once at the same interval by the camera module arranged above the side of the polishing pad to obtain a detection image group; the spacing length between the first marking light and the second marking light in each detection image in the detection image group is measured, and the length is defined as the detection length; the actual depth of the groove in each detection image is calculated by the following formula;

[0015] H n =L n ÷Sin∠α

[0016] In the formula, H n is the actual depth of the groove; L n is the detection length in the detection image; Sin∠α is the sine value of the calculated angle.

[0017] A comparison scale is prepared according to the detection length in each detection image in the detection image group and the actual depth in each detection image in the detection image group, so that the detection length on the comparison scale corresponds to the value of the actual depth one by one.

[0018] Optionally, the acquired detection image includes at least the bottom of the groove on the side away from the camera module; the detection length is the distance between the endpoint of the second marking light at the bottom of the groove on that side and the endpoint of the first marking light closest to the bottom of the groove on that side.

[0019] Optionally, the sine value of the angle is calculated using the following formula.

[0020] Cos∠α=L c ÷L b

[0021] (Sin∠α) 2 +(Cos∠α) 2 =1

[0022] Where Cos∠α is the cosine value of the angle to be calculated; L b is the length of the second measuring line; L c is the length of the first measurement line.

[0023] Optionally, the actual depth of the groove is calculated by a data processing module in the CMP system, and the data processing module is connected to the camera module to obtain a detection image; the calculated angle is input and set after calculation; the comparison scale is obtained after calculation by the data processing module and stored in the data processing module.

[0024] Optionally, the camera module is adapted to move in a horizontal direction to obtain multiple groups of multi-angle detection images to support calculation of actual depths of all grooves on the polishing pad.

[0025] The technical solution of the present invention has the following advantages:

[0026] The polishing pad detection method provided by the present invention obtains the actual depth of the groove of the polishing pad in the CMP system by setting a marking light, obtaining the sine value of the calculated angle, obtaining a detection image, and calculating the formula. In practical applications, since the detection process is never in direct contact with the polishing pad, no damage is caused to the surface of the polishing pad. Since the data is obtained by calculation, the error is smaller than that of manual measurement. In addition, the present solution can measure the actual depth of the polishing pad in the CMP system without stopping the machine, and the operation is simple and efficient. The depth value obtained in real time can be used as an input for adjusting the polishing process parameters to more accurately control the polishing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 A schematic diagram of a marking light in the polishing pad groove depth detection method provided by the present invention;

[0029] Figure 2 A side view schematic diagram showing the position of a marking light in the polishing pad groove depth detection method provided by the present invention;

[0030] Figure 3 A schematic diagram of the principle of calculating the groove depth in the polishing pad groove depth detection method provided by the present invention;

[0031] Figure 4 A schematic diagram of a process flow of an embodiment of a polishing pad groove depth detection method provided by the present invention;

[0032] Figure 5 A schematic flow chart of another embodiment of the polishing pad groove depth detection method provided by the present invention;

[0033] Figure 6 for Figure 5 A schematic flow chart of the steps for obtaining a comparison scale in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to solve the problems of low efficiency, easy surface damage and large error in manually measuring the depth of the polishing pad groove during shutdown, the present invention provides a polishing pad groove depth detection method, comprising the following steps: providing a CMP system and a polishing pad; setting a marker light, projecting the marker light to the groove of the polishing pad through an optical module, and the marker light spanning the width direction of the groove; defining the portion of the marker light on the surface of the polishing pad as the first marker light, and defining the portion of the marker light at the bottom of the groove as the second marker light; obtaining the sine value of the calculated angle, defining the horizontal line where the camera module is located to the second marker light and the groove of the polishing pad away from the camera module The line at the intersection of the side wall on one side is defined as the first measurement line, and the line from the camera module to the intersection of the second marking light and the groove side wall is defined as the second measurement line; the angle between the second measurement line and the first measurement line is defined as the calculated angle, and the sine value of the calculated angle is obtained through the installation position of the camera module; the detection image is obtained, and after the CMP system has been running for a period of time, the polishing pad is photographed by the camera module arranged above the side of the polishing pad to obtain the detection image; the spacing length between the first marking light and the second marking light at this time is measured, and the length is defined as the detection length; the actual depth of the groove at this time is calculated by the following formula.

[0035] H m =L m ÷Sin∠α

[0036] In the formula, H m is the actual depth of the groove; L m is the detection length in the detection image; Sin∠α is the sine value of the calculated angle.

[0037] The present invention also provides another method for detecting the depth of a polishing pad groove, comprising the following steps: providing a CMP system and a polishing pad; obtaining a detection image of the polishing pad by means of a camera module disposed above the side of the polishing pad in the CMP system; providing a comparison scale, the comparison scale being a scale of the actual height of the groove of the polishing pad in the detection image and the visual length of the groove of the polishing pad in the detection image, and obtaining the actual height of the groove by reading the comparison scale.

[0038] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] 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.

[0042] Example 1

[0043] refer to Figure 1 to Figure 4 , this embodiment provides a polishing pad groove depth detection method, comprising the following steps:

[0044] Providing a CMP system and a polishing pad 1;

[0045] Set up marker rays; see Figure 1 and Figure 2, a marking light is projected onto the groove 2 of the polishing pad 1 through an optical module (not shown in the figure), and the marking light spans the width direction of the groove 2; the portion of the marking light on the surface of the polishing pad is defined as the first marking light 3, and the portion of the marking light at the bottom of the groove is defined as the second marking light 4.

[0046] Acquire a detection image; after the CMP system runs for a period of time, photograph the polishing pad 1 through the camera module 5 disposed above the side of the polishing pad 1 to acquire a detection image; measure the spacing length between the first marking light 3 and the second marking light 4 at this time, and define the length as the detection length;

[0047] Get the sine value of the calculated angle; reference Figure 3 , the camera module 5 is located at point C, point A is the vertex of the side wall of the groove away from the camera module, and point B is the intersection of the bottom and the side wall of the groove away from the camera module. Define the line connecting the horizontal line (CD line) where the camera module 5 is located to the intersection point B of the second marking light 4 and the side wall of the groove of the polishing pad away from the camera module as the first measurement line (DB line), define the camera module 5 ( Figure 3 The line connecting the second marking light and the intersection B of the groove of the polishing pad away from the camera module is the second measuring line (CB line); the angle between the second measuring line CB and the first measuring line DB is defined as the calculated angle α (∠CBD in the figure), and the angle of the calculated angle α is obtained through the installation position of the camera module 5.

[0048] Calculate the actual depth of the groove; at this time, the actual depth of groove 2 is calculated by the following formula:

[0049] H m =L m ÷Sin∠α

[0050] In the formula, H m is the actual depth of the groove; L m is the detection length in the detection image; Sin∠α is the sine value of the calculated angle α.

[0051] Furthermore, in the step of acquiring the detection image, the acquired detection image at least includes the bottom of the groove on the side away from the camera module, that is, at least includes Figure 3 At point B in the middle, point B cannot be blocked; the detection length is the distance between the endpoint of the second marking light 4 at the bottom of the side groove (that is, point B) and the endpoint of the first marking light 3 closest to the bottom of the side groove, that is, the distance between the two opposite endpoints 3 and 4 in the detection image.

[0052] Since the camera module 5 is disposed above the side of the polishing pad 1, due to the direct light and the camera's photography principle, the detection length in the detection image is actually Figure 3Therefore, the actual depth of groove 2 can be calculated by calculating the sine value of angle α Sin∠α and the detection length, that is, Figure 3 The length of the middle AB line.

[0053] Furthermore, the angle α is calculated by the following formula.

[0054] Cos∠α=L c ÷L b

[0055] (Sin∠α) 2 +(Cos∠α) 2 =1

[0056] Where Cos∠α is the cosine value of the angle α, that is, the cosine value of ∠CBD; L b is the length of the second measurement line, that is, the length of line DB; L c is the length of the first measurement line, that is, the length of line CB. Since Cos∠α can be measured by the length of the second measurement line L b and the length L of the first measuring line c The length L of the first measurement line is obtained by calculation. c and the length L of the second measuring line b It is simple and easy to obtain, so we can solve the formula (Sin∠α) 2 +(Cos∠α) 2 =1 to obtain the sine value Sin∠α of the angle α.

[0057] Therefore, the polishing pad detection method provided in this embodiment obtains the actual depth of the groove 2 of the polishing pad 1 in the CMP system by setting a marking light, obtaining a detection image, obtaining the sine value of the calculated angle, and calculating the formula. In practical applications, since the detection process is never in direct contact with the polishing pad 1, the surface of the polishing pad 1 will not be damaged. Since the data is obtained by calculation, the error is smaller than that of manual measurement. In addition, the present solution can measure the actual depth of the polishing pad in the CMP system without stopping the machine, and the operation is simple and efficient. The actual depth value obtained in real time can be used as an input for adjusting the polishing process parameters to more accurately control the polishing accuracy.

[0058] In addition, in some other embodiments, the actual depth of the groove can be calculated by a data processing module in the CMP system, and the data processing module is connected to the camera module to obtain the detection image; the calculated angle is input and set after the calculation. In this way, fully automatic detection can be achieved.

[0059] The camera module may be, for example, a CCD camera. The optical module may be any linear light source, so long as a linear marking beam can be formed on the surface of the polishing pad.

[0060] Example 2

[0061] refer to Figure 5-Figure 6 , and also refer to Figure 1-Figure 3 The present invention also provides another polishing pad groove depth detection method, comprising the following steps:

[0062] Provide CMP systems and polishing pads;

[0063] The inspection image of the polishing pad 1 is obtained by a photographing module 5 disposed above the side of the polishing pad 1 in the CMP system.

[0064] A comparison scale is provided, which is a scale of the actual height of the groove 2 of the sample polishing pad 1 in the detection image and the visual length of the groove 2 of the sample polishing pad 1 in the detection image, and the actual height of the groove is obtained by reading the comparison scale.

[0065] Specifically, the comparison scale is obtained by the following steps:

[0066] Providing a CMP system and a sample polishing pad 1;

[0067] A marking light is set and projected onto the groove 2 of the sample polishing pad 1 through an optical module, wherein the marking light spans the width direction of the groove 2; the portion of the marking light on the surface of the sample polishing pad 1 is defined as the first marking light 3, and the portion of the marking light at the bottom of the groove is defined as the second marking light 4.

[0068] Acquire a detection image group. After running the CMP system, take a picture of the sample polishing pad 1 once at the same interval through the camera module 5 arranged above the side of the polishing pad to acquire the detection image at that moment. All the detection images constitute a detection image group. Measure the spacing length between the first marking light 3 and the second marking light 4 in each detection image in the detection image group, and define the length as the detection length.

[0069] Get the sine value of the calculated angle; reference Figure 3 , the camera module 5 is located at point C, point A is the vertex of the side wall of the groove away from the camera module, and point B is the intersection of the bottom and the side wall of the groove away from the camera module. Define the line connecting the horizontal line (CD line) where the camera module 5 is located to the intersection point B of the second marking light 4 and the side wall of the groove of the polishing pad away from the camera module as the first measurement line (DB line), define the camera module 5 ( Figure 3 The line connecting the second marking light and the intersection B of the groove of the polishing pad away from the camera module is the second measuring line (CB line); the angle between the second measuring line CB and the first measuring line DB is defined as the calculated angle α (∠CBD in the figure), and the angle of the calculated angle α is obtained through the installation position of the camera module 5.

[0070] Calculate the actual depth of the groove 2 in each detection image; the actual depth of the groove 2 in each detection image is calculated by the following formula;

[0071] H n =L n ÷Sin∠α

[0072] In the formula, H n is the actual depth of the groove; L n is the detection length in the detection image; Sin∠α is the sine value of the calculated angle.

[0073] A comparison scale is prepared; a comparison scale is prepared according to the detection length in each detection image in the detection image group and the actual depth in each detection image in the detection image group, so that the detection length on the comparison scale corresponds to the value of the actual depth. The comparison scale can be a physical scale for measuring readings, or a scale in the form of data stored in a data processing module of the CMP system. The actual height of the groove is obtained by the reading of the comparison scale.

[0074] Furthermore, in the step of acquiring the detection image, the acquired detection image at least includes the bottom of the groove on the side away from the camera module, that is, at least includes Figure 3 At point B in the middle, point B cannot be blocked; the detection length is the distance between the endpoint of the second marking light 4 at the bottom of the side groove (that is, point B) and the endpoint of the first marking light 3 closest to the bottom of the side groove, that is, the distance between the two opposite endpoints 3 and 4 in the detection image.

[0075] Furthermore, the angle α is calculated by the following formula.

[0076] Cos∠α=L c ÷L b

[0077] (Sin∠α) 2 +(Cos∠α) 2 =1

[0078] Where Cos∠α is the cosine value of the angle α, that is, the cosine value of ∠CBD; L b is the length of the second measurement line, that is, the length of line DB; L c is the length of the first measurement line, that is, the length of line CB. Since Cos∠α can be measured by the length of the second measurement line L b and the length L of the first measuring line c The length L of the first measurement line is obtained by calculation. c and the length L of the second measuring line b It is simple and easy to obtain, so we can solve the formula (Sin∠α) 2 +(Cos∠α)2 =1 to obtain the sine value Sin∠α of the angle α.

[0079] Therefore, the polishing pad detection method provided in this embodiment obtains the actual depth of the groove 2 of the polishing pad 1 in the CMP system by setting a marking light, obtaining a detection image, obtaining the sine value of the calculated angle, and calculating the formula. In practical applications, since the detection process is never in direct contact with the polishing pad 1, the surface of the polishing pad 1 will not be damaged. Since the data is obtained by calculation, the error is smaller than that of manual measurement. In addition, the present solution can measure the actual depth of the polishing pad in the CMP system without stopping the machine, and the operation is simple and efficient. The actual depth value obtained in real time can be used as an input for adjusting the polishing process parameters to more accurately control the polishing accuracy.

[0080] In addition, in some other embodiments, the actual depth of the groove can be calculated by a data processing module in the CMP system, and the data processing module is connected to the camera module to obtain the detection image; the calculated angle is input and set after the calculation. In this way, fully automatic detection can be achieved.

[0081] The present invention has been described above by way of embodiments. It is believed that those skilled in the art can understand the present invention through the above embodiments. Obviously, the above embodiments are merely examples for the purpose of clear description, 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 present invention.

Claims

1. A method for detecting the depth of a polishing pad groove, characterized in that: Provide CMP systems and polishing pads; Setting a marking light, projecting the marking light to the groove of the polishing pad through an optical module, wherein the marking light spans the width direction of the groove; defining the portion of the marking light on the surface of the polishing pad as a first marking light, and defining the portion of the marking light at the bottom of the groove as a second marking light; Acquire a detection image. After the CMP system runs for a period of time, photograph the polishing pad by a camera module disposed above the side of the polishing pad to acquire a detection image. Measure the distance between the first marking light and the second marking light at this time, and define the distance as a detection length. Obtaining the sine value of the calculated angle, defining a line from the horizontal line where the camera module is located to the intersection of the second marking light and the side wall of the groove of the polishing pad away from the camera module as a first measurement line, defining a line from the camera module to the intersection of the second marking light and the side wall of the groove of the polishing pad away from the camera module as a second measurement line; defining the angle between the second measurement line and the first measurement line as the calculated angle, and obtaining the sine value of the calculated angle according to the installation position of the camera module; The actual depth of the groove is calculated. At this time, the actual depth of the groove is calculated by the following formula: H m =L m ÷Sin∠α In the formula, H m is the actual depth of the groove; L m is the detection length in the detection image; Sin∠α is the sine value of the calculated angle; In the step of acquiring the detection image, the acquired detection image at least includes the bottom of the groove on the side away from the camera module; The detection length is the distance between the end point of the second marking light at the bottom of the side groove and the end point of the first marking light closest to the bottom of the side groove; The sine value of the calculated angle is calculated by the following formula: Cos∠α=L c ÷L b (Sin∠α) 2 +(Cos∠α) 2 =1 Wherein, Cos∠α is the cosine value of the calculated angle; L b is the length of the second measurement line; L c is the length of the first measurement line.

2. The polishing pad groove depth detection method according to claim 1, characterized in that: The actual depth of the groove is calculated by a data processing module in the CMP system, and the data processing module is connected to the camera module to obtain the detection image; the calculated angle is input and set after the calculation.

3. A method for detecting the depth of a polishing pad groove, characterized in that: The following steps are involved: Provide CMP system and sample polishing pads; Acquiring a detection image of the polishing pad by means of a camera module disposed above the side of the polishing pad in the CMP system; Providing a comparison scale, wherein the comparison scale is a scale of the actual height of the groove of the sample polishing pad in the detection image and the visual length of the groove of the sample polishing pad in the detection image, and the actual height of the groove is obtained by reading the comparison scale; Wherein, the comparison scale is obtained by the following steps: Provide CMP system and sample polishing pads; Setting a marking light, projecting the marking light to the groove of the sample polishing pad through an optical module, wherein the marking light spans the width direction of the groove; defining the portion of the marking light on the surface of the sample polishing pad as a first marking light, and defining the portion of the marking light at the bottom of the groove as a second marking light; Acquire a detection image group, after running the CMP system, photograph the sample polishing pad once at the same interval through a camera module disposed above the side of the polishing pad, and acquire a detection image at that moment, and all the detection images constitute a detection image group; measure the spacing length between the first marking light and the second marking light in each detection image in the detection image group, and define the length as the detection length; Obtain the sine value of the calculated angle, define a line from the horizontal line where the camera module is located to the intersection of the second marking light and the side wall of the groove of the sample polishing pad away from the camera module as a first measurement line, and define a line from the camera module to the intersection of the second marking light and the side wall of the groove as a second measurement line; define the angle between the second measurement line and the first measurement line as the calculated angle, and obtain the sine value of the calculated angle according to the installation position of the camera module; Calculating the actual depth of the groove in each of the detection images, the actual depth of the groove in each of the detection images is calculated by the following formula; H n =L n ÷Sin∠α In the formula, H n is the actual depth of the groove; L n is the detection length in the detection image; Sin∠α is the sine value of the calculated angle; A comparison scale is obtained, wherein the comparison scale is obtained according to the detection length in each detection image in the detection image group and the actual depth in each detection image in the detection image group, so that the detection length on the comparison scale corresponds to the value of the actual depth one by one; The acquired detection image at least includes the groove bottom on the side of the groove away from the camera module; the detection length is the distance between the end point of the second marking light at the groove bottom on the side and the end point of the first marking light closest to the groove bottom on the side; The sine value of the calculated angle is calculated by the following formula: Cos∠α=L c ÷L b (Sin∠α) 2 +(Cos∠α) 2 =1 Wherein, Cos∠α is the cosine value of the calculated angle; L b is the length of the second measurement line; L c is the length of the first measurement line.

4. The polishing pad groove depth detection method according to claim 3, characterized in that: The calculation of the actual depth of the groove is performed by the data processing module in the CMP system, and the data processing module is connected to the camera module to obtain the detection image; the calculated angle is input and set after calculation; the comparison scale is obtained after calculation by the data processing module and stored in the data processing module.

5. The polishing pad groove depth detection method according to claim 1 or 3, characterized in that: The photographing module is suitable for moving in a horizontal direction to obtain multiple groups of multi-angle detection images to support the calculation of the actual depths of all the grooves on the polishing pad.

Images