Method and system for detecting surface state of loading platform

Abstract

A method and a system for detecting a surface state of a loading platform, comprising: acquiring, by a processor, a reference surface profile data comprising a plurality of first distances corresponding to a plurality of sampling points on a surface of a loading platform; the processor controls the non-contact height measuring device to scan the detection plate adsorbed on the surface of the object carrying platform to measure a second distance between the detection plate and the detection plate at each sampling point, and the processor generates to-be-measured surface contour data containing the sampling points and the corresponding second distances; and according to the difference between the first distance corresponding to the sampling point contained in the reference surface contour data and the second distance corresponding to the sampling point contained in the to-be-detected surface contour data, whether particles exist on the surface of the loading platform or not is judged, and a detection result is generated.

Description

Technical Field

[0001] The present invention relates to a surface state detection method, and particularly to a surface state detection method for a carrier platform applied to semiconductor measurement or detection equipment. Background Art

[0002] Semiconductor measurement or detection equipment includes a carrier platform (chuck) for carrying a test object, such as a wafer. When dust or particles such as fragments left by the previous test object adhere to the surface of the carrier platform, if the test object is directly placed on the carrier platform, due to the existence of the aforementioned dust or fragments between the test object and the carrier platform, there may be errors in the measurement or detection results of the test object, or there is a risk that the test object is damaged by the aforementioned dust or fragments. Therefore, before measuring or detecting the test object, ensuring the cleanliness of the surface of the carrier platform is indeed a topic worthy of research. Summary of the Invention

[0003] An object of the present invention is to provide a surface state detection method and system for a carrier platform, which can effectively detect particles adhering to the surface of the carrier platform of semiconductor measurement or detection equipment.

[0004] A surface state detection method for a carrier platform of the present invention includes: a processor obtaining reference surface profile data, the reference surface profile data including a plurality of first distances corresponding to a plurality of sampling points on the surface of the carrier platform; the surface of the carrier platform adsorbing a detection plate; the processor controlling a non-contact height measuring device to scan the detection plate adsorbed on the surface of the carrier platform and measuring a second distance between the detection plate and the detection plate at each of the sampling points; the processor generating measured surface profile data including the sampling points and the corresponding second distances according to the second distances provided by the non-contact height measuring device; the processor judging whether there are particles on the surface of the carrier platform according to the gap between the first distances corresponding to the sampling points included in the reference surface profile data and the second distances corresponding to the sampling points included in the measured surface profile data and generating a detection result.

[0005] A surface state detection system for a load platform to implement the above method includes a processor, a detection plate, and a non-contact height measuring device. The processor obtains reference surface profile data, which includes a plurality of first distances corresponding to a plurality of sampling points on the surface of the load platform. The detection plate is adsorbed by the surface of the load platform. The non-contact height measuring device is electrically connected to the processor and controlled by the processor. Among them, the non-contact height measuring device is controlled by the processor to scan the detection plate adsorbed on the surface of the load platform and measure the second distance between it and the detection plate at each of the sampling points. The processor generates measured surface profile data including the sampling points and their corresponding second distances based on the second distances provided by the non-contact height measuring device. The processor generates a detection result based on the difference between the first distance corresponding to the sampling point included in the reference surface profile data and the second distance corresponding to the sampling point included in the measured surface profile data, and the detection result indicates whether there are particles on the surface of the load platform.

[0006] In some embodiments of the present invention, when the difference between the first distance and the second distance corresponding to the corresponding sampling points in the reference surface profile data and the measured surface profile data is greater than a critical value, the detection result indicates that there are particles at the sampling point on the surface of the load platform.

[0007] In some embodiments of the present invention, the load platform is placed on a mobile vehicle. While the mobile vehicle is controlled by the processor to drive the load platform to move relative to the non-contact height measuring device along a preset movement path, the non-contact height measuring device is controlled by the processor to scan and measure the second distance between it and the detection plate at each of the sampling points.

[0008] In some embodiments of the present invention, the first distances included in the reference surface profile data are generated by the non-contact height measuring device being controlled by the processor to scan the detection plate adsorbed on the surface of the load platform with a reference state or a predetermined state and measure the distance between it and the detection plate at each of the sampling points, where the reference state refers to a state where there are no particles on the surface of the load platform, and the predetermined state refers to a state where there are no particles on the surface of the load platform or a state where there are ineradicable particles on the surface of the load platform.

[0009] In some embodiments of the present invention, the non-contact height measuring device is a color confocal displacement sensor, a laser displacement meter, a capacitive displacement meter, or an atomic force microscope.

[0010] The beneficial effect of the present invention is that by adsorbing the detection plate on the surface of the load platform and then scanning and measuring the height (profile) of the surface of the detection plate, the detection ability of particles on the surface of the load platform can be improved. Description of the Drawings

[0011] Figure 1 These are the main process steps of an embodiment of the method for detecting the surface state of the load platform of the present invention.

[0012] Figure 2 This is a schematic diagram of the main components included in an embodiment of the system for detecting the surface state of the load platform of the present invention.

[0013] Figure 3 It shows that the non-contact height measuring instrument in this embodiment scans multiple sampling points on the surface of the test plate adsorbed on the surface of the load platform with a reference state or a predetermined state, and measures the first distance from each sampling point.

[0014] Figure 4 It shows that the non-contact height measuring instrument in this embodiment scans the surface of the test plate adsorbed on the surface of the load platform to be measured at the same sampling points as shown in Figure 3 and measures the second distance from each sampling point.

[0015] Figure 5 It shows that the second distance corresponding to the sampling point shown in Figure 4 is subtracted from the first distance corresponding to the sampling point shown in Figure 3 to obtain the gap corresponding to the sampling point.

[0016] Figure 6 It shows that in this embodiment, the non-contact height measuring instrument scans the same sampling points as shown in Figure 3 on the surface of the load platform with a reference state or a predetermined state, and measures the third distance from each sampling point.

[0017] Figure 7 It shows that the non-contact height measuring instrument in this embodiment scans the same sampling points as shown in Figure 3 on the surface of the load platform to be measured, and measures the fourth distance from each sampling point.

[0018] Figure 8 It shows that the fourth distance corresponding to the sampling point shown in Figure 7 is subtracted from the third distance corresponding to the sampling point shown in Figure 6 to obtain the gap corresponding to the sampling point. Detailed implementation manner

[0019] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0020] Before the present invention is described in detail, it should be noted that in the following description, similar components are denoted by the same reference numerals.

[0021] Refer to Figure 1, which are the main process steps of an embodiment of the method for detecting the surface state of the loading platform of the present invention, and this embodiment is implemented by Figure 2 the surface state detection system shown, which mainly includes a detection plate 1, a processor 2, and a non-contact height measuring device 3 controlled by the processor 2.

[0022] As Figure 2 and Figure 3 shown, the detection plate 1 is used to be placed on the surface of the loading platform 41 of a semiconductor measuring or detecting device 4 for placing a test object (such as, but not limited to, a wafer) and is tightly adsorbed by the surface of the loading platform 41. The way of tight adsorption is, for example, that the surface of the loading platform 41 is provided with a plurality of air holes (not shown in the figure). The semiconductor measuring or detecting device 4 applies negative pressure to the air holes to adsorb the detection plate 1 and make it closely fit on the surface of the loading platform 41, and this is also the way for the loading platform 41 to adsorb the test object on its surface.

[0023] The detection plate 1 is a plate with the same size as the test object except for the film, such as, but not limited to, a bare wafer.

[0024] As Figure 2 shown, the processor 2 is a central processing unit, a microprocessor, or a microcontroller, etc. of a computer that is set in the semiconductor measuring or detecting device 4 and controls the operation of the semiconductor measuring or detecting device 4. And the processor 2 is electrically connected to a moving vehicle 42 that carries the loading platform 41 of the semiconductor measuring or detecting device 4 to control the moving vehicle 42 to move the loading platform 41 within a preset range to measure or detect the test object placed on the surface of the loading platform 41.

[0025] As Figure 2 shown, the non-contact height measuring device 3 is set in the semiconductor measuring or detecting device 4 and is located above the loading platform 41. And the non-contact height measuring device 3 is electrically connected to the processor 2 and is actuated under the control of the processor 2. The non-contact height measuring device 3 can be, but not limited to, a color confocal displacement sensor, a laser displacement meter, a capacitive displacement meter, or an atomic force microscope (AFM).

[0026] And after the semiconductor measuring or detecting device 4 is delivered from the factory and used by the operator to measure or detect the test object for a period of time (such as 1 month, 3 months, or half a year, etc.), there may be particles, such as dust or fragments of the previously detected test object, etc., adhering to the surface of the loading platform 41. Therefore, every once in a while (such as 1 month, 3 months, or half a year, etc.), before measuring or detecting the test object, it should be first detected whether there are particles on the surface of the loading platform 41 to timely remove the particles on the surface of the loading platform 41.

[0027] Therefore, in order to detect the particles on the surface of the carrier platform 41, such as Figure 1 in step S1, first, the processor 2 obtains a reference surface profile data, which includes a plurality of first distances corresponding to a plurality of sampling points on the surface of the carrier platform 41.

[0028] The reference surface profile data can be generated and provided by the manufacturer when the semiconductor measurement or detection device 4 leaves the factory (or is shipped). For example, at the manufacturer's end, the processor 2 controls the non-contact height measuring device 3 to scan the detection plate 1 adsorbed on the surface of the carrier platform 41 in a reference state and measure the distance between it (the non-contact height measuring device 3) and the detection plate 1 at each sampling point to generate the first distances corresponding to the sampling points; the reference state can refer to the state where there are no particles on the surface of the carrier platform 41, and after the above sampling operation and cleaning, the detection plate 1 is put back into a storage box (not shown in the figure).

[0029] Alternatively, the reference surface profile data can also be generated by the semiconductor measurement or detection device 4 at the user end (industry end) before the previous (or previous) measurement or detection of the object to be measured. For example, the processor 2 controls the non-contact height measuring device 3 to scan the detection plate 1 adsorbed on the surface of the carrier platform 41 in a predetermined state and measure the distance between it (the non-contact height measuring device 3) and the detection plate 1 at each sampling point to generate the first distances corresponding to the sampling points. The predetermined state can be the above reference state (the state where there are no particles on the surface of the carrier platform 41) or the state where there are some ineliminable particles on the surface of the carrier platform 41, and after the above sampling operation and cleaning, the detection plate 1 is put back into the storage box.

[0030] Specifically, during the process of obtaining the first distance, the processor 2 controls the mobile vehicle 42 to drive the load platform 41 to move relative to the non-contact height measuring device 3 along a preset action path. At the same time, the processor 2 controls the non-contact height measuring device 3 to scan and measure the distances between its measuring probe (not shown in the figure) and the surface of the detection plate 1 adsorbed on the surface of the load platform 41 at each sampling point at a default sampling frequency. For example, if the processor 2 expects to obtain the first distance at M (rows) x N (columns) sampling points evenly distributed on the surface of the detection plate 1, when the N sampling points in the first row of the surface of the detection plate 1 adsorbed on the surface of the load platform 41 are moved to directly below the measuring probe (not shown in the figure) of the non-contact height measuring device 3, the processor 2 commands the non-contact height measuring device 3 to scan (single-point scanning one by one or multi-point scanning simultaneously) and measure the first distances between the N sampling points in the first row of the surface of the detection plate 1 and the measuring probe respectively. Then, when the N sampling points in the second row of the surface of the detection plate 1 adsorbed on the surface of the load platform 41 are moved to directly below the measuring probe (not shown in the figure) of the non-contact height measuring device 3, the processor 2 commands the non-contact height measuring device 3 to scan and measure the first distances between the N sampling points in the second row of the surface of the detection plate 1 and the measuring probe respectively.

[0031] For example Figure 3 As shown, when the non-contact height measuring device 3 scans a series of consecutive sampling points in a certain row of the surface of the detection plate 1 adsorbed on the surface of the load platform 41, the first distances corresponding to each sampling point are measured. Figure 3 The horizontal arrow in it indicates the scanning direction of the non-contact height measuring device 3.

[0032] In this way, the non-contact height measuring device 3 will scan and measure the first distances between the N sampling points in the 3rd to Mth rows on the surface of the detection plate 1 and it row by row, and obtain the first distances corresponding to the sampling points (i.e., M x N sampling points).

[0033] Therefore, the reference surface profile data can present the height change of the surface of the detection plate 1 adsorbed on the surface of the load platform 41 (which is also the height change of the surface of the load platform 41) in the reference state or the established state. For example Figure 3 As shown.

[0034] Then, perform Figure 1 Step S2, so that the detection plate 1 is adsorbed on the surface of the load platform 41 to be measured. The detection plate 1 is taken out from the storage box by a fetching mechanism (such as a robotic arm) of the semiconductor measuring or detecting device 4 and placed on the load platform 41.

[0035] Next, as Figure 1In step S3, the processor 2 controls the mobile vehicle 42 to drive the load platform 41 to move relative to the non-contact height measuring device 3 along the preset movement path described above. At the same time, the processor 2 controls the non-contact height measuring device 3 to scan and measure a second distance between it and the test plate 1 adsorbed on the surface of the load platform 41 at each of the sampling points (i.e., the above-mentioned MxN sampling points), and provides the second distance corresponding to the sampling points (i.e., MxN sampling points) to the processor 2.

[0036] Take Figure 4 as an example, Figure 4 It shows that when the non-contact height measuring device 3 scans and measures the surfaces of a plurality of consecutive sampling points in a certain row on the surface of the test plate 1 adsorbed on the surface of the load platform 41 (for example, the consecutive sampling points in the same row as shown in Figure 3 ), when some particles (such as Figure 4 the 1st and 3rd particles in Figure 4 ) on the surface of the load platform 41 do not fall on the sampling points but fall beside or near the sampling points, the test plate 1 will magnify these particles, expand the range of these particles and extend it to the sampling points that fall beside or near, so that when the non-contact height measuring device 3 scans and measures the corresponding second distance at the sampling points beside or near these particles, these second distances can reflect or highlight the existence of the particles that fall beside or near the sampling points, as shown in

[0037] It is worth mentioning that in order to keep the time spent in the detection process within a reasonable range and not consume too much detection time, the sampling (scanning) frequency and scanning spacing (the spacing between two adjacent sampling points) of the non-contact height measuring device 3 need to be reasonably planned. Therefore, the sampling frequency cannot be set too high and the scanning spacing cannot be reduced to a very small value. In this case, there will be some sampling points of the non-contact height measuring device 3 that just do not fall on the positions where some particles on the surface of the load platform 41 exist. However, in this embodiment, the test plate 1 adsorbed on the surface of the load platform 41 can magnify these particles, so that the range of these particles can extend to the sampling points that fall beside or near and can be sampled by the non-contact height measuring device 3.

[0038] Then, as in Figure 1 step S4, after the processor 2 receives the second distance transmitted by the non-contact height measuring device 3, based on the coordinates of the sampling points and the second distance corresponding to the sampling points (i.e., MxN sampling points), it generates a surface profile data to be measured including the sampling points (coordinates) and their corresponding second distances. The surface profile data to be measured presents the height change of the surface of the test plate 1 adsorbed on the surface of the load platform 41 (which is also the height change of the surface of the load platform 41 to be measured), such as Figure 4 shown.

[0039] Next, as in Figure 1 step S5, the processor 2 determines whether there are particles on the surface of the carrier platform 41 based on the difference between the first distance corresponding to the sampling point included in the reference surface profile data and the second distance corresponding to the sampling point included in the surface profile data to be measured, and generates a detection result.

[0040] Specifically, for example Figure 5 as shown, the processor 2 subtracts the first distance corresponding to the sampling point (for example, Figure 4 the consecutive sampling points in a certain row as shown) included in the surface profile data to be measured from the second distance corresponding to the sampling point (for example, Figure 3 the sampling points shown in the same row as Figure 4 shown) included in the reference surface profile data, and a surface profile difference data including the sampling point and a corresponding difference as shown in Figure 5 will be obtained. Then, the processor 2 determines whether the difference corresponding to a certain sampling point or some sampling points in the surface profile difference data is greater than a critical value ( Figure 5 the dashed line in), and if so, it is determined that there are particles (for example, Figure 5 the 5 circled sampling points in) on the surface of the carrier platform 41 at the sampling point or these sampling points (for example, Figure 5 the 3 large black dots shown in), and generates the detection result, and the detection result shows that there are particles on the surface of the carrier platform 41 and need to be cleaned. And the test plate 1 is put back into the storage box after completing the above detection operation and being cleaned.

[0041] In addition, to prove that this embodiment has better particle detection ability, as Figure 6 shown, another reference surface profile data including the sampling point (coordinates) and the corresponding third distance is obtained in the same way as above. The third distance is generated by scanning the surface of the carrier platform 41 in the reference state or the established state without adsorbing the test plate 1 by the non-contact height measuring device 3 at the same sampling points as above and measuring the distance between each sampling point, as Figure 6 shown ( Figure 6 showing the third distances of consecutive multiple sampling points in the same row as Figure 3 shown); then, as Figure 7 , the surface of the carrier platform 41 to be measured without adsorbing the test plate 1 (i.e., the surface with particles 411 adhered as Figure 4 shown) is scanned by the non-contact height measuring device 3 at the above sampling points and the fourth distance between each sampling point is measured, and another surface profile data to be measured including the sampling point (coordinates) and the corresponding fourth distance is generated by the processor 2, asFigure 7 as shown Figure 7 display the Figure 3 fourth distance for a plurality of consecutive sampling points on the same line as shown).

[0042] and as Figure 8 shown, the processor 2 subtracts the other surface profile data of the other surface to be measured from the other reference surface profile data to obtain another surface profile difference data, and the processor 2 further determines according to another critical value ( Figure 8 the dashed line in) whether the gap corresponding to a certain sampling point or certain sampling points in the other surface profile difference data is greater than the other critical value, so as to determine whether there are particles at the sampling point or sampling points; and in this case, Figure 8 only one sampling point in the continuous sampling points shown has a gap greater than the other critical value, so that the processor 2 can only determine that there are particles at one sampling point (for example Figure 8 the 1 circled sampling point in), and the other two particles (for example Figure 8 the 1 large black dot in the middle corresponding to the circled sampling point) that fall beside or near the sampling point cannot be detected by the non-contact height measuring device 3 because they do not fall on the sampling point position. Among them, the other critical value is basically the critical value of this embodiment minus the thickness of the test plate 1, but not limited thereto, and the critical value of this embodiment is basically determined according to the experimental results. Figure 8 the two large black dots on the left and right in) are not detected because they do not fall on the sampling point position. Among them, the other critical value is basically the critical value of this embodiment minus the thickness of the test plate 1, but not limited thereto, and the critical value of this embodiment is basically determined according to the experimental results.

[0043] It can be seen from this that in this embodiment, by adsorbing the test plate 1 on the surface of the carrier platform 41 and then scanning and measuring the height (profile) of the surface of the test plate 1, the detection ability of particles on the surface of the carrier platform 41 can be effectively improved.

[0044] In summary, in the above embodiment, by obtaining the reference surface profile data composed of the heights (i.e., the first distance) of a plurality of sampling points on the surface of the test plate 1 adsorbed on the surface of the carrier platform 41 having the reference state or the established state and obtaining the surface profile data to be measured composed of the heights (i.e., the second distance) of the sampling points on the surface of the test plate 1 adsorbed on the surface of the carrier platform 41 to be measured, and according to the gap between the surface profile data to be measured and the reference surface profile data, it is determined whether there are particles on the surface of the carrier platform 41 to be measured, and the detection ability of particles on the surface of the carrier platform 41 is improved, which truly achieves the effects and purposes of the present invention.

Claims

1. A method for detecting the surface state of a loading platform, characterized in that: The processor obtains reference surface profile data, which includes a plurality of first distances corresponding to a plurality of sampling points on the surface of the carrier platform; The surface of the carrier platform adsorbs the test plate; The processor controls the non-contact height measuring device to scan the test plate adsorbed on the surface of the carrier platform and measure the second distance between it and the test plate at each of the sampling points; The processor generates measured surface profile data including the sampling points and their corresponding second distances based on the second distances provided by the non-contact height measuring device; and The processor determines whether there are particles on the surface of the carrier platform and generates a detection result based on the difference between the first distance corresponding to the sampling point included in the reference surface profile data and the second distance corresponding to the sampling point included in the measured surface profile data.

2. The method for detecting the surface state of a loading platform according to claim 1, characterized in that: When the processor determines that the difference between the first distance and the second distance corresponding to the corresponding sampling points in the reference surface profile data and the measured surface profile data is greater than the critical value, the processor determines that there are particles at the sampling point on the surface of the carrier platform.

3. The method for detecting the surface state of a loading platform according to claim 1, characterized in that: The carrier platform is placed on a mobile vehicle, and while the mobile vehicle is controlled by the processor to drive the carrier platform to move relative to the non-contact height measuring device according to a preset action path, the processor controls the non-contact height measuring device to scan and measure the second distance between it and the test plate at each of the sampling points.

4. The method for detecting the surface state of a loading platform according to claim 1, characterized in that: The first distances included in the reference surface profile data are generated by the processor controlling the non-contact height measuring device to scan the test plate adsorbed on the surface of the carrier platform in a reference state or a predetermined state and measure the distance between it and the test plate at each of the sampling points, where the reference state refers to the state where there are no particles on the surface of the carrier platform, and the predetermined state refers to the state where there are no particles on the surface of the carrier platform or the state where there are ineradicable particles on the surface of the carrier platform.

5. The method for detecting the surface state of a loading platform according to any one of claims 1 to 4, characterized in that: The non-contact height measuring device is a color confocal displacement sensor, a laser displacement meter, a capacitive displacement meter, or an atomic force microscope.

6. A system for detecting the surface state of a loading platform, characterized in that: The surface state detection system of the carrier platform includes: A processor that obtains reference surface profile data, which includes a plurality of first distances corresponding to a plurality of sampling points on the surface of the carrier platform; A test plate that is adsorbed by the surface of the carrier platform; and A non-contact height measuring device that is electrically connected to the processor and controlled by the processor; where The non-contact height measuring device is controlled by the processor to scan the test plate adsorbed on the surface of the carrier platform and measure the second distance between it and the test plate at each of the sampling points; The processor generates measured surface profile data including the sampling points and their corresponding second distances based on the second distances provided by the non-contact height measuring device; The processor generates a detection result based on the difference between the first distance corresponding to the sampling point included in the reference surface profile data and the second distance corresponding to the sampling point included in the measured surface profile data, and the detection result indicates whether there are particles on the surface of the carrier platform.

7. The system for detecting the surface state of a loading platform according to claim 6, characterized in that: When the difference between the first distance and the second distance corresponding to the corresponding sampling points in the reference surface profile data and the surface profile data to be measured is greater than the critical value, the detection result indicates that there are particles at the sampling points on the surface of the carrier platform.

8. The system for detecting the surface state of a loading platform according to claim 6, characterized in that: The carrier platform is placed on a mobile vehicle. While the mobile vehicle is controlled by the processor to drive the carrier platform to move relative to the non-contact height measuring device along a preset action path, the non-contact height measuring device is controlled by the processor to scan and measure the second distance between it and the test sheet at each sampling point.

9. The system for detecting the surface state of a loading platform according to claim 6, characterized in that: The first distance included in the reference surface profile data is generated when the non-contact height measuring device is controlled by the processor to scan the test sheet adsorbed on the surface of the carrier platform in a reference state or a predetermined state and measure the distance between it and the test sheet at each sampling point. The reference state refers to the state where there are no particles on the surface of the carrier platform, and the predetermined state refers to the state where there are no particles on the surface of the carrier platform or the state where there are particles that cannot be eliminated on the surface of the carrier platform.

10. The system for detecting the surface state of a loading platform according to any one of claims 6 to 9, characterized in that: The non-contact height measuring device is a chromatic confocal displacement sensor, a laser displacement meter, a capacitive displacement meter, or an atomic force microscope.

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