A flatness testing method and apparatus

Abstract

The present application relates to a kind of flatness test method and device, method includes the following steps: selecting flat reference surface, flat reference surface is opposite parallel with the test surface of polishing pad;Multiple first test points are set on test surface;Multiple first test points and the distance of flat reference surface are obtained, recorded as first distance;The sample variance of first distance is calculated, recorded as first variance D1;The flatness of polishing pad is judged according to the first variance.Compared with prior art, the flatness of the above-mentioned method is used as standard to judge the flatness of polishing pad, effectively improves flatness test precision and efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polishing pad testing technology, in particular to a flatness testing method and device. BACKGROUND

[0002] CMP (Chemical Mechanical Polishing) is a polishing technology combining mechanical grinding of abrasive particles and chemical corrosion of polishing liquid to overcome the shortcomings of chemical polishing and mechanical polishing. The biggest advantage of CMP is that it can achieve nanometer global planarization of the processed surface, meeting the requirements of ultra-precision non-damage surface processing for integrated circuit feature sizes below 0.35 μm. Semiconductor devices usually require nanometer-level flatness, and the best current technology is a combination of polishing liquid (chemical) and polishing pad (mechanical). CMP is not only used in integrated circuit chips, but also commonly used in the processing of discrete semiconductor devices and electronic components. In addition, it has also been expanded to the surface processing field of thin-film storage disks, ceramics, sapphire, etc.

[0003] The polishing pad, also known as the grinding pad, has a rough surface with protrusions or grooves, and is used to directly contact the chip to produce friction, mechanically remove the polishing layer on the semiconductor surface, and uniformly spread the polishing liquid onto the surface of the polishing pad under the action of centrifugal force to chemically remove the polishing layer on the semiconductor surface while carrying away the reaction products. Therefore, the flatness of the polishing pad directly affects the surface quality of the wafer and is related to the planarization effect of the semiconductor surface.

[0004] The current method for detecting the flatness of the polishing pad is to randomly select points for thickness measurement using a thickness gauge, and to calculate the flatness based on the thickness measurement results of multiple sampling points. Since the thickness measurement sampling points selected by humans have random distribution, the flatness calculated based on the thickness measurement results also has a large systematic error. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a flatness testing method and device to improve the testing efficiency and accuracy of the flatness of the polishing pad.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A flatness testing method, comprising the following steps:

[0008] Selecting a flat reference surface that is parallel to the testing surface of the polishing pad;

[0009] Setting a plurality of first testing points on the testing surface;

[0010] acquiring distances between the first test points and the flat reference surface, denoted as first distances;

[0011] calculating a sample variance of the first distances, denoted as a first variance D1;

[0012] judging the flatness of the polishing pad according to the first variance.

[0013] In one embodiment, the judging the flatness of the polishing pad according to the first variance comprises the following steps:

[0014] calculating the flatness of the polishing pad according to the following formula:

[0015]

[0016] wherein F is the flatness of the polishing pad, and a and ε are constants, and satisfy: 0.8≤a≤1.2, 0.01≤ε≤0.16;

[0017] setting a qualified range of the flatness;

[0018] judging whether the flatness is within the qualified range, when the flatness is within the qualified range, the polishing pad is qualified, and when the flatness is beyond the qualified range, the polishing pad is unqualified.

[0019] In one embodiment, the qualified range of the flatness is 0.02-0.15.

[0020] In one embodiment,

[0021] the selecting the flat reference surface comprises the following steps:

[0022] selecting the flat reference surface such that the flat reference surface is oppositely arranged with the test table;

[0023] arranging the polishing pad on the test table such that a test surface of the polishing pad is oppositely parallel with the flat reference surface;

[0024] the judging the flatness of the polishing pad according to the first variance comprises the following steps:

[0025] setting a plurality of second test points on the test table, each of which corresponds to one of the first test points;

[0026] acquiring distances between the second test points and the flat reference surface, denoted as second distances;

[0027] calculating a sample variance of the second distances, denoted as a second variance D2;

[0028] determining flatness of the polishing pad according to the first variance and the second variance.

[0029] In one embodiment, the determining flatness of the polishing pad according to the first variance and the second variance comprises:

[0030] The flatness of the polishing pad is calculated according to the following formula:

[0031]

[0032] wherein F is the flatness of the polishing pad, and a, β and ε are constants, and satisfy: 0.8≤a≤1.2, 0.8≤β≤1.2, 0.01≤ε≤0.16;

[0033] setting a qualified range of the flatness;

[0034] determining whether the flatness is within the qualified range, when the flatness is within the qualified range, the polishing pad is qualified, and when the flatness is beyond the qualified range, the polishing pad is unqualified.

[0035] In one embodiment, in the setting multiple first test points on the test surface, the multiple first test points are distributed in concentric circles around the center of the test surface.

[0036] In one embodiment, in the setting multiple first test points on the test surface, the multiple first test points are arranged in intersecting manner, and the intersection point coincides with the center of the test surface.

[0037] A flatness testing device suitable for the flatness testing method described above, the device comprises:

[0038] a selection module, the selection module is used for selecting a flat reference surface, so that the flat reference surface is oppositely arranged with a test surface of a polishing pad, and the selection module is also used for selecting multiple first test points on the test surface;

[0039] a testing module, the testing module is used for acquiring distances between the multiple first test points and the flat reference surface;

[0040] a judging module, the judging module is used for determining flatness of the polishing pad according to the multiple first distances.

[0041] In one embodiment, the testing module comprises:

[0042] a testing table, the testing table is provided with a bearing surface for placing a polishing pad, and the bearing surface is provided with multiple air holes;

[0043] A vacuum pump is arranged to communicate with the air hole, and is used to vacuum the space between the bearing surface and the polishing pad.

[0044] A test assembly is arranged opposite to the bearing surface, and includes a plurality of distance measuring sensors.

[0045] In one embodiment, the selection module includes a first sliding rod and a fixed support, one end of the fixed support is connected with the distance measuring sensor, and the other end of the fixed support is slidingly connected with the first sliding rod, so that the distance measuring sensor can be close to or away from the bearing surface relative to the first sliding rod.

[0046] Compared with the prior art, the present application has the following advantages:

[0047] 1. The above method selects a flat reference surface, tests the distance between the flat reference surface and the first test point on the polishing pad, and judges the flatness of the polishing pad according to a plurality of first distances. If the test surface on the polishing pad is an ideal plane, the distance between the flat reference surface and any point on the test surface is equal. When the test surface on the polishing pad is not flat, the distances between the flat reference surface and a plurality of test points on the test surface are inevitably not equal, i.e. the plurality of first distances are not equal. Therefore, the flatness of the polishing pad can be judged by the variance between the plurality of first distances. The smaller the variance between the plurality of first distances, the better the flatness of the polishing pad. The larger the variance between the plurality of first distances, the worse the flatness of the polishing pad. The above method uses the flatness of the flat reference surface as a standard to judge the flatness of the polishing pad, effectively improving the flatness test precision and efficiency.

[0048] 2. The flatness of the polishing pad is quantitatively calculated according to the variance of the first distance, a unified evaluation standard for the flatness of different polishing pads is established, and the judgment efficiency and precision of the flatness of the polishing pad are improved.

[0049] 3. For the polishing pad placed on the test table, a second test point corresponding to the first test point is arranged on the test table, and a second distance between the second test point and the flat reference surface is obtained. The flatness of the polishing pad is judged according to the first distance and the second distance, the unevenness of the test table is avoided to cause the flatness measurement error of the polishing pad, and the flatness test precision of the polishing pad is further improved.

[0050] 4. The flatness of the polishing pad is quantitatively calculated according to the variance of the first distance and the second distance, and the judgment efficiency and precision of the flatness of the polishing pad are improved. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 FIG. 1 is a flowchart of the flatness test method in one embodiment.

[0052] Figure 2 This is a flowchart illustrating the flatness testing method in another embodiment.

[0053] Figure 3 This is a schematic diagram of the flatness testing device in one embodiment.

[0054] Figure 4 This is a top view of a flatness testing device in one embodiment.

[0055] Figure 5 This is a schematic diagram of the sampling points of the polishing pad in one embodiment.

[0056] Figure descriptions: 100, Flatness testing device; 10, Test platform; 11, Bearing surface; 12, Air hole; 13, Positioning component; 20, Vacuum pump; 30, Test assembly; 31, Distance sensor; 32, Fixed bracket; 321, First extension rod; 322, Rotating frame; 33, First intermediate component; 34, First sliding rod; 40, Automatic input device; 41, Second sliding rod; 42, Second extension rod; 43, Second intermediate component; 50, Polishing pad. Detailed Implementation

[0057] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0058] like Figure 1 As shown, in one embodiment, a flatness testing method is provided, including the following steps:

[0059] Step S100: Select a flat reference surface, which is parallel to the test surface of the polishing pad 50;

[0060] Step S200: Set multiple first test points on the test surface;

[0061] Step S300: Obtain the distances between multiple first test points and the flat reference surface, and record them as the first distances;

[0062] Step S400: Calculate the sample variance of the first distance, denoted as the first variance D1;

[0063] Step S500: Determine the flatness of the polishing pad 50 based on the first variance.

[0064] The above method selects a flat reference surface, tests the distance between the flat reference surface and the first test point on the polishing pad 50, and determines the flatness of the polishing pad 50 according to the plurality of first distances. If the test surface on the polishing pad 50 is an ideal plane, the distance between the flat reference surface and any point on the test surface is equal. When the test surface on the polishing pad 50 is not flat, it will inevitably lead to the distance between the flat reference surface and the plurality of test points on the test surface being not equal, that is, the plurality of first distances are not equal. The flatness of the polishing pad 50 is determined by the variance between the plurality of first distances. The smaller the variance between the plurality of first distances, the better the flatness of the polishing pad 50. The larger the variance between the plurality of first distances, the worse the flatness of the polishing pad 50. Therefore, the above method determines the flatness of the polishing pad 50 by taking the flatness of the flat reference surface as a standard, effectively improving the flatness test precision and efficiency.

[0065] Further, in an embodiment, step S400 comprises the following steps:

[0066] Step A: Calculate the flatness of the polishing pad 50 according to the following formula:

[0067]

[0068] Wherein F is the flatness of the polishing pad 50, and α and ε are constants, and satisfy: 0.8≤α≤1.2, 0.01≤ε≤0.16;

[0069] Step B: Set the qualified range of flatness;

[0070] Step C: Determine whether the flatness is within the qualified range. When the flatness is within the qualified range, the polishing pad 50 is qualified. When the flatness exceeds the qualified range, the polishing pad 50 is unqualified.

[0071] The above method quantitatively calculates the flatness of the polishing pad 50 according to the variance of the first distance, establishes a unified evaluation standard for the flatness of different polishing pads 50, and is beneficial to improve the judgment efficiency and precision of the flatness of the polishing pad 50.

[0072] In the present embodiment, the qualified range of flatness is 0.02-0.15 in the qualified range of flatness.

[0073] Specifically, as shown in the figure, Figure 2 In an embodiment, step S100 comprises the following steps:

[0074] Step S101: Select a flat reference surface, and the flat reference surface is arranged opposite to the test table 10;

[0075] Step S102: Lay the polishing pad 50 on the test table 10, and make the test surface of the polishing pad 50 opposite to the flat reference surface.

[0076] Further, with reference to the above description Figure 2 In an embodiment, step S500 comprises the following steps:

[0077] Step S501: setting a plurality of second test points corresponding to the first test points on the test table 10;

[0078] Step S502: obtaining the distances between the plurality of second test points and the flat reference surface, denoted as second distances;

[0079] Step S503: calculating the sample variance of the second distances, denoted as second variance D2;

[0080] Step S504: judging the flatness of the polishing pad 50 according to the first variance and the second variance.

[0081] For the polishing pad 50 placed on the test table 10, the above method sets second test points corresponding to the first test points on the test table 10, obtains second distances between the second test points and the flat reference surface, and judges the flatness of the polishing pad 50 according to the first distances and the second distances, thereby avoiding the unevenness of the test table 10 to cause the measurement error of the flatness of the polishing pad 50, and being beneficial to further improve the flatness test precision of the polishing pad 50.

[0082] In the specific embodiment, step S504 comprises the following steps:

[0083] Step A: calculating the flatness of the polishing pad 50 according to the following formula:

[0084]

[0085] wherein F is the flatness of the polishing pad 50, and a, β and ε are constants, and satisfy: 0.8≤a≤1.2, 0.8≤β≤1.2, 0.01≤ε≤0.16;

[0086] Step B: setting the qualified range of the flatness;

[0087] Step C: judging whether the flatness is within the qualified range, when the flatness is within the qualified range, the polishing pad 50 is qualified, and when the flatness exceeds the qualified range, the polishing pad 50 is unqualified.

[0088] The above method quantitatively calculates the flatness of the polishing pad 50 according to the variances of the first distances and the second distances, which is beneficial to improve the judgment efficiency and precision of the flatness of the polishing pad 50.

[0089] Specifically, in an embodiment, in the plurality of first test points set on the test surface, the plurality of first test points are distributed in concentric circles around the center of the test surface.

[0090] Optionally, in an embodiment, the plurality of first test points are arranged in intersecting arrangement, and the intersection points thereof coincide with the center of the test surface, i.e. among the plurality of first test points arranged on the test surface, a portion of the first test points are arranged in a first direction, and another portion of the first test points are arranged in a second direction, the first direction intersecting the second direction.

[0091] Specifically, in an embodiment, the flatness testing method further comprises the following steps:

[0092] Obtaining the basic information of the polishing pad, the basic information comprising production batch, material, hardness and density of the polishing pad;

[0093] Corresponding the basic information of the polishing pad with the flatness.

[0094] In an embodiment, a flatness testing device 100 is provided, which is suitable for the flatness testing method described above, and the device comprises:

[0095] A selection module, the selection module being configured to select a flat reference surface, and the flat reference surface being arranged opposite to the test surface of the polishing pad 50, and the selection module being further configured to select a plurality of first test points on the test surface;

[0096] A testing module, the testing module being configured to obtain the distances between the plurality of first test points and the flat reference surface;

[0097] A judging module, the judging module being connected with the testing module, and the judging module being configured to judge the flatness of the polishing pad 50 according to the plurality of first distances.

[0098] Specifically, in an embodiment, the judging module is further configured to calculate the sample variance of the first distances, and to judge the flatness of the polishing pad 50 according to the first variance.

[0099] In the specific embodiment, the judging module is configured to calculate the flatness of the polishing pad 50 according to the following formula:

[0100]

[0101] wherein F is the flatness of the polishing pad 50, and a and ε are constants, and satisfy: 0.8≤a≤1.2, 0.01≤ε≤0.16;

[0102] The judging module is configured to set the qualified range of the flatness, and to judge whether the flatness is within the qualified range, when the flatness is within the qualified range, the polishing pad 50 is qualified, and when the flatness exceeds the qualified range, the polishing pad 50 is unqualified.

[0103] Specifically, in an embodiment, the selecting module is configured to select a flat reference surface, and the flat reference surface is arranged opposite to the test table 10, and is configured to arrange a plurality of second test points on the test table 10, and the plurality of second test points correspond to the plurality of first test points one by one; the testing module is further configured to obtain a plurality of second distances between the plurality of second test points and the flat reference surface; and the judging module is configured to judge the flatness of the polishing pad 50 according to the plurality of first distances and the plurality of second distances.

[0104] In the specific embodiment, the testing module is further configured to calculate a sample variance of the first distances, calculate a sample variance of the second distances, and judge the flatness of the polishing pad 50 according to the first variance and the second variance.

[0105] Specifically, as shown in Figure 3 and Figure 4 , in an embodiment, the testing module includes the test table 10, the vacuum pump 20, and the test assembly 30. The test table 10 is provided with a bearing surface 11 for placing the polishing pad 50, and the bearing surface 11 is distributed with a plurality of air holes 12; the inlet of the vacuum pump 20 is communicated with the air holes 12, and is configured to vacuum the space between the bearing surface 11 and the polishing pad 50; and the test assembly 30 includes a plurality of distance measuring sensors 31, and the distance measuring sensors 31 are arranged opposite to the bearing surface 11. The projection position of the distance measuring sensors 31 on the polishing pad 50 is the first test point, and the projection position of the distance measuring sensors 31 on the test table 10 is the second test point. The distances between the plurality of distance measuring sensors 31 and the test table 10 are equal, and the ends of the plurality of distance measuring sensors 31 facing the polishing pad 50 form a plane, and the plane is selected as the flat reference surface. Therefore, the distance measuring sensors 31 only need to test the distances between the distance measuring sensors 31 and the polishing pad 50 to obtain the first distances, and test the distances between the distance measuring sensors 31 and the test table 10 to obtain the second distances.

[0106] Among them, the plurality of air holes 12 on the bearing surface 11 are distributed in concentric circles around the center of the bearing surface 11. The air holes 12 are uniformly distributed between the bearing surface 11 and the polishing pad 50, so that the polishing pad 50 receives the same suction force everywhere, and ensures that the polishing pad 50 is evenly laid on the bearing surface 11.

[0107] At the same time, as shown in Figure 5 , the plurality of distance measuring sensors 31 are arranged in intersection, and the intersection point is located on the axis of the test table 10, that is, a part of the distance measuring sensors 31 are distributed along a first direction, and another part of the distance measuring sensors 31 are distributed along a second direction, and the first direction and the second direction are arranged in intersection. Or the plurality of distance measuring sensors 31 are arranged in concentric circles around the axis of the test table 10. Understandably, the distribution relationship of the plurality of distance measuring sensors 31 is the distribution relationship of the plurality of sampling point positions on the polishing pad 50, and the more uniform the distribution of the plurality of sampling point positions on the polishing pad 50, the higher the testing accuracy of the flatness.

[0108] Further, assuming that the ranging sensors are in a cross-shaped distribution, the center of the rotating frame coincides with the center of the bearing surface, when the ranging sensors are in the first position, the ranging sensors perform distance test on the polishing pad to obtain the first set of distance data, at this time, the rotating frame is rotated by an angle a around the center of the bearing surface, the ranging sensors are in the second position, the ranging sensors perform distance test on the polishing pad again to obtain the second set of distance data, and then the flatness of the polishing pad is calculated according to the first set of distance data and the second set of distance data. That is, for the same polishing pad, since the rotating frame can rotate around the center of the bearing surface, the ranging sensors can obtain multiple sets of distance data at different radius positions on the polishing pad, thereby improving the basic data for flatness calculation and improving the accuracy of flatness test.

[0109] In the specific embodiment, the bearing surface 11 is provided with a plurality of positioning members 13 protruding from the bearing surface 11 for abutting against the side periphery of the polishing pad 50. The bearing surface 11 is provided with a plurality of positioning members 13 for limiting the placement position of the polishing pad 50, ensuring that different polishing pads 50 are placed at the same position on the bearing surface 11, and when the relative position between the ranging sensors 31 and the bearing surface 11 is unchanged, the sampling positions of different polishing pads 50 are consistent, thereby realizing the consistency of the flatness evaluation system of different polishing pads 50. The plurality of positioning members 13 are arranged in concentric circles around the center of the bearing surface 11, and the positioning members 13 are movably connected to the testing table 10, so that the positioning members 13 can protrude from the bearing surface 11 or be flush with the bearing surface 11, and the positioning members 13 on different circles are used for abutting against polishing pads 50 of different sizes. The positioning members 13 arranged in concentric circles on the bearing surface 11 can be set to protrude from the bearing surface 11 and be flush with the bearing surface 11, when the diameter of the polishing pad 50 is small, the positioning members 13 in the inner circle can be set to protrude from the bearing surface and abut and fix the polishing pad 50, and when the diameter of the polishing pad 50 is large, the positioning members 13 in the inner circle can be set to be flush with the bearing surface 11, and the positioning members 13 in the outer circle can protrude from the bearing surface 11, and the polishing pad 50 covers the positioning members 13 in the inner circle and abuts against the positioning members 13 in the outer circle. Therefore, the testing table 10 can abut and fix polishing pads 50 of different diameters, thereby improving the application range of the testing device.

[0110] Specifically, as Figure 3 and Figure 4As shown, in one embodiment, the selection module includes a driver, a first sliding rod 34, a first intermediate member 33, and a fixed bracket 32. One end of the first intermediate member 33 is slidably connected to the first sliding rod 34, and the first intermediate member 33 slides up and down along the first sliding rod 34. The other end of the first intermediate member 33 is rotatably connected to the fixed bracket 32, so that the fixed bracket 32 ​​can rotate relative to the first intermediate member 33 about a vertical axis. In this specific embodiment, the fixed bracket 32 ​​includes a first extension rod 321 and a rotating frame 322. One end of the first extension rod 321 is slidably connected to the first sliding rod 34, and the other end of the first extension rod 321 is rotatably connected to the rotating frame 322, so that the rotating frame 322 rotates about the axis of the test platform 10. A distance sensor 31 is provided on the rotating frame 322.

[0111] The driver is used to drive the first intermediate component 33 to move up and down relative to the first sliding rod 34, adjust the distance between the distance sensor 31 and the test platform 10, thereby adjusting the distance between the flat reference surface and the test platform 10.

[0112] The driver is also used to drive the fixed bracket 32 ​​to rotate relative to the first intermediate member 33, drive the rotating frame 322 to rotate relative to the first extension rod 321, adjust the projection position of the ranging sensor 31 on the polishing pad 50, and realize the selection of the position of the first test point.

[0113] Specifically, in one embodiment, the judgment module includes a controller connected to the ranging sensor 31, which is used to receive a first distance and a second distance obtained by the ranging sensor 31, calculate a first variance and a second variance based on the first distance and the second distance, and judge the flatness of the polishing pad 50 based on the first variance and the second variance.

[0114] Furthermore, such as Figure 3 As shown, in one embodiment, the device further includes an automatic input device 40, the controller is electrically connected to the automatic input device 40, the automatic input device 40 is disposed opposite to the bearing surface 11, and is used to scan and input the basic information of the polishing pad 50.

[0115] The controller can obtain the test distance from the ranging sensor 31, and obtain the flatness of the polishing pad 50 based on the test distance, and integrate the flatness of the polishing pad 50 with the basic information.

[0116] In the embodiment, the device comprises a second sliding rod 41, a second extension rod 42 and a second intermediate piece 43. One end of the second intermediate piece 43 is in sliding connection with the second sliding rod 41, so that the automatic input device 40 can move close to or away from the bearing surface 11 relative to the second sliding rod 41. The second intermediate piece 43 is in rotational connection with one end of the second extension rod 42, so that the second extension rod 42 can rotate around a vertical axis. The other end of the second extension rod 42 is connected with the automatic input device 40. Therefore, the second extension rod 42 can drive the automatic input device 40 to rotate around a vertical axis, so as to adjust the projection position of the automatic input device 40 on the bearing surface 11, so as to adapt to different positions of the two-dimensional code on the polishing pad 50.

[0117] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0118] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0119] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0120] In the present application, unless specifically stated and limited otherwise, a first feature "on" or "under" a second feature can be directly in contact with the second feature, or indirectly in contact with the second feature through an intermediate medium. Also, a first feature "over", "above" and "on top of" a second feature can be directly above or obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature. A first feature "under", "below" and "underneath" a second feature can be directly below or obliquely below the second feature, or simply means that the first feature is horizontally lower than the second feature.

[0121] It is noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0122] Any technical features in the above embodiments can be combined arbitrarily, and for the sake of brevity, all possible combinations of technical features in the above embodiments are not described, however, as long as the combinations of technical features do not contradict each other, they should be considered within the scope of the present specification.

Claims

1. A flatness testing method characterized by, The method comprises the following steps: selecting a flat reference surface, and arranging the flat reference surface opposite to the test table; laying the polishing pad on the test table, and arranging the test surface of the polishing pad parallel to the flat reference surface; arranging a plurality of first test points on the test surface; acquiring distances between the plurality of first test points and the flat reference surface, and denoting the distances as first distances; calculating sample variances of the first distances, and denoting the sample variances as first variances D1; arranging a plurality of second test points on the test table, and arranging the second test points one by one corresponding to the first test points; acquiring distances between the plurality of second test points and the flat reference surface, and denoting the distances as second distances; calculating sample variances of the second distances, and denoting the sample variances as second variances D2; judging the flatness of the polishing pad according to the first variances and the second variances; The flatness testing device is formed; a bearing surface for placing the polishing pad is arranged on the test table; a plurality of air holes distributed in concentric circles around the center of the bearing surface and a plurality of positioning members distributed in concentric circles around the center of the bearing surface are arranged on the bearing surface; the positioning members protrude from the bearing surface and are communicated with the air holes through a vacuum pump; the space between the bearing surface and the polishing pad is vacuumized; the positioning members abut against the side of the polishing pad; and the polishing pad is laid flat on the bearing surface. A first sliding rod is arranged on the test table; a first intermediate member is connected to the first sliding rod in up-down sliding mode; one end of the first intermediate member is rotationally connected to a first extension rod; the other end of the first extension rod is rotationally connected to a rotating frame; a plurality of distance measuring sensors are arranged on the rotating frame in intersecting arrangement or concentric circle distribution around the rotating center of the rotating frame; the plane where the plurality of distance measuring sensors face one end of the polishing pad is the flat reference surface; the distance between the test table and the flat reference surface is determined by up-down sliding of the first intermediate member on the first sliding rod; the distribution center of the distance measuring sensors is coaxial with the center of the bearing surface by rotating the first extension rod relative to the first intermediate member around a vertical shaft; and the position distribution of the distance measuring sensors is the position distribution of the first test points by adjusting the rotation of the rotating frame on the first extension rod. The flatness of the polishing pad is judged according to the first variances and the second variances, and the method comprises the following steps: The flatness of the polishing pad is calculated according to the following equation: ; wherein F is the flatness of the polishing pad, and α, β and ε are constants, and satisfy: 0.8≤α≤1.2, 0.8≤β≤1.2, 0.01≤ε≤0.16; a qualified range of the flatness is set; whether the flatness is located in the qualified range is judged; when the flatness is located in the qualified range, the polishing pad is qualified; and when the flatness exceeds the qualified range, the polishing pad is unqualified.

2. A flatness testing method according to claim 1, wherein In the setting of the qualified range of the flatness, the qualified range of the flatness is 0.02-0.

15.

3. A flatness testing method according to claim 1 or 2, characterised in that, In the setting of the plurality of first test points on the test surface, the plurality of first test points are distributed in concentric circles around the center of the test surface.

4. A method of testing flatness according to claim 1 or 2, wherein In the setting of the plurality of first test points on the test surface, the plurality of first test points are arranged in intersecting arrangement, and the intersection points coincide with the center of the test surface.

5. A flatness testing device characterized by, The device is suitable for the flatness testing method in any one of claims 1-4. The selection module is configured to select a flat reference surface, and to arrange the flat reference surface opposite to a test surface of a polishing pad, and to select a plurality of first test points on the test surface; and the selection module is further configured to arrange a plurality of second test points on a test table corresponding to the first test points one by one. The test module is configured to obtain distances between the plurality of first test points and the flat reference surface, denoted as first distances; and to obtain distances between the plurality of second test points and the flat reference surface, denoted as second distances. The judgment module is configured to judge flatness of the polishing pad according to the plurality of first distances and the plurality of second distances.

6. The flatness testing device of claim 5, wherein, The test module comprises: The test table is provided with a bearing surface for placing the polishing pad, and the bearing surface is provided with a plurality of air holes; A vacuum pump is provided, and an inlet of the vacuum pump is communicated with the air holes, and the vacuum pump is configured to vacuum the space between the bearing surface and the polishing pad; The test assembly comprises a plurality of distance measuring sensors, and the distance measuring sensors are arranged opposite to the bearing surface.

7. The flatness testing device of claim 5, wherein, The selection module comprises a first sliding rod and a fixed support, one end of the fixed support is connected with the distance measuring sensor, and the other end of the fixed support is slidingly connected with the first sliding rod, so that the distance measuring sensor can move close to or away from the bearing surface relative to the first sliding rod.

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