TWI869113B - Method and system for detecting surface condition of loading platform - Google Patents

Abstract

A method for detecting the surface condition of a loading platform. The processor obtains a reference surface profile data including a plurality of first distances corresponding to multiple sampling points on the surface of a loading platform, and after a detection plate is adsorbed on the surface of the loading platform, the processor controls the non-contact height measuring device to scan the detection plate adsorbed on the surface of the loading platform to measure a second distance between it and the detection plate at each sampling point, and the processor generates a surface profile data to be measured including the sampling points and their corresponding second distances, and according to the difference between the first distance corresponding to the sampling points included in the reference surface profile data and the second distance corresponding to the sampling points included in the surface profile data to be measured, the processor determines whether the surface of the loading platform exists particles and produces a detecting result.

Description

Method and system for detecting surface state of loading platform

The present invention relates to a surface state detection method, and in particular to a surface state detection method for a carrier platform used in semiconductor measurement or detection equipment.

Semiconductor measurement or testing equipment includes a chuck for carrying an object to be tested, such as a wafer. When the surface of the chuck is stained with dust or particles such as debris left by the previous object to be tested, if the object to be tested is placed directly on the chuck, due to the presence of the dust or debris particles between the object to be tested and the chuck, the measurement or test results of the object to be tested may be erroneous, or the object to be tested may be damaged by the dust or debris particles. Therefore, before measuring or testing the object to be tested, ensuring that the surface of the chuck is clean is indeed a topic worth studying.

Therefore, the purpose of the present invention is to provide a method for detecting the surface state of a carrier platform and a system for detecting the surface state of a carrier platform for implementing the method, which can effectively detect particles adhering to the surface of the carrier platform of a semiconductor measurement or detection device.

Therefore, the present invention provides a method for detecting the surface state of a loading platform, comprising: a processor obtaining a 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 a loading platform; the surface of the loading platform adsorbs a detection plate; the processor controls a non-contact height measuring device to scan the detection plate adsorbed on the surface of the loading platform and measure a second distance between the detection plate and the detection plate at each sampling point. The processor generates a surface profile data to be measured including the sampling points and the second distances corresponding to the sampling points according to the second distances provided by the non-contact height measuring device; and the processor determines whether there are particles on the surface of the loading platform and generates a detection result according to the difference 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 surface profile data to be measured.

Furthermore, the present invention implements the above-mentioned method in a platform surface state detection system, comprising a processor, a detection plate and a non-contact height measuring device; the processor obtains a reference surface profile data, the reference surface profile data including a plurality of first distances corresponding to a plurality of sampling points on a platform surface; the detection plate is adsorbed by the platform surface; the non-contact height measuring device is electrically connected to the processor and controlled by the processor; wherein the processor controls the non-contact height measuring device to scan the platform surface The detection plate adsorbed on the surface is measured to measure a second distance between the detection plate and the detection plate at each sampling point; the processor generates a surface profile data to be detected including the sampling points and the second distances corresponding to the sampling points according to the second distances provided by the non-contact height measuring device; the processor determines whether there are particles on the surface of the carrier platform and generates a detection result according to the difference 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 surface profile data to be detected.

In some embodiments of the present invention, when the processor determines that the difference between the first distance and the second distance corresponding to a sampling point corresponding to the benchmark surface profile data and the measured surface profile data is greater than a critical value, the processor determines that there are particles on the surface of the carrier platform at the sampling point.

In some embodiments of the present invention, the carrier platform is placed on a mobile carrier, and the mobile carrier is controlled by the processor to move the carrier platform relative to the non-contact height meter according to a preset moving path. At the same time, the processor controls the non-contact height meter to scan and measure the second distance between it and the detection plate at each sampling point.

In some embodiments of the present invention, the first distances included in the reference surface profile data are generated by the processor controlling the non-contact height meter to scan the detection plate adsorbed by the surface of the carrier platform having a reference state or a predetermined state and measuring the distance between it and the detection plate at each sampling point, wherein the reference state refers to a state in which there are no particles on the surface of the carrier platform, and the predetermined state refers to a state in which there are no particles on the surface of the carrier platform or a state in which there are some particles on the surface of the carrier platform that cannot be eliminated.

In some embodiments of the present invention, the non-contact height measurement device is a chromatic confocal displacement sensor, a laser displacement meter, a capacitive displacement meter or an atomic force microscope.

The effect of the present invention is that the detection capability of particles on the surface of the loading platform can be improved by adsorbing the detection plate on the surface of the loading platform and then scanning and measuring the height (profile) of the surface of the detection plate.

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

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

As shown in Figures 2 and 3, the detection plate 1 is used to be placed on the surface of a carrier platform 41 of a semiconductor measurement or detection equipment 4 for placing a test object (for example but not limited to a wafer) and is tightly adsorbed by the surface of the carrier platform 41. The tight adsorption method is, for example, that the surface of the carrier platform 41 is provided with a plurality of air holes (not shown in the figure). The semiconductor measurement or detection equipment 4 applies negative pressure to the air holes to adsorb the detection plate 1 so that it is tightly attached to the surface of the carrier platform 41, and this is also the way in which the carrier platform 41 adsorbs the test object on its surface.

The detection plate 1 is a plate having the same size as the object to be detected except for a film, such as but not limited to a bare wafer.

As shown in FIG. 2 , the processor 2 is a central processing unit, a microprocessor or a microcontroller of a computer that is installed 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 carrier 42 that carries the carrier platform 41 of the semiconductor measuring or detecting device 4 to control the moving carrier 42 to move the carrier platform 41 within a preset range to measure or detect the object to be tested placed on the surface of the carrier platform 41 .

As shown in FIG. 2 , the non-contact height measuring device 3 is disposed on the semiconductor measurement or testing equipment 4 and is located above the carrier platform 41 , and the non-contact height measuring device 3 is electrically connected to the processor 2 and is controlled by the processor 2 to act. The non-contact height measuring device 3 may be, but is not limited to, a color confocal displacement sensor, a laser displacement meter, a capacitive displacement meter or an atomic force microscope (AFM).

Moreover, when the semiconductor measuring or testing device 4 is used by the industry to measure or test the object to be tested for a period of time (e.g., 1 month, 3 months, or half a year, etc.) after leaving the factory, particles, such as dust or fragments of the object to be tested previously tested, may adhere to the surface of the carrier platform 41; therefore, at regular intervals (e.g., 1 month, 3 months, or half a year, etc.), before measuring or testing the object to be tested, the surface of the carrier platform 41 should be checked for particles so that the particles on the surface of the carrier platform 41 can be removed in time.

Therefore, in order to detect the particles on the surface of the carrier platform 41, as shown in step S1 of FIG. 1, first, the processor 2 obtains a reference surface profile data, wherein the reference surface profile data includes a plurality of first distances corresponding to a plurality of sampling points on the surface of the carrier platform 41.

The reference surface profile data may 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 having a reference state and measures 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 may refer to a state in which there are no particles on the surface of the carrier platform 41, and the detection plate 1 is placed back into a storage box (not shown) after completing the above-mentioned sampling action and being cleaned.

Alternatively, the reference surface profile data may also be generated by the semiconductor measuring or testing device 4 at the user end (industry end) before the last (or before) measurement or testing of the object to be tested, for example, the processor 2 controls the non-contact height measuring device 3 to scan the test plate 1 adsorbed on the surface of the carrier platform 41 having a predetermined state and measures the distance between it (the non-contact height measuring device 3) and the test plate 1 at each sampling point to generate the first distances corresponding to the sampling points. The predetermined state may be the reference state (the state in which there are no particles on the surface of the carrier platform 41) or the state in which there are some particles that cannot be eliminated on the surface of the carrier platform 41, and the test plate 1 is put back into the storage box after completing the above sampling action and being cleaned.

Specifically, in the process of obtaining the first distances, the processor 2 controls the mobile carrier 42 to drive the carrier platform 41 to move relative to the non-contact height measuring device 3 according to a preset moving path. At the same time, the processor 2 controls the non-contact height measuring device 3 to scan and measure the distance between the non-contact height measuring device 3 and the surface of the detection plate 1 adsorbed on the surface of the carrier platform 41 at each sampling point at a preset sampling frequency. For example, the processor 2 expects to obtain the first distance at M (row) x N (column) sampling points evenly distributed on the surface of the detection plate 1. Then, when the N sampling points on the first row of the surface of the detection plate 1 adsorbed on the surface of the carrier platform 41 are moved to the non-contact height measuring device 3, the first distance is obtained. When the N sampling points on the first row of the surface of the detection plate 1 adsorbed on the surface of the loading platform 41 are moved to the position directly below the measuring probe (not shown) of the non-contact height measuring device 3, the processor 2 enables the non-contact height measuring device 3 to scan (single point scanning or simultaneous multi-point scanning) and measure the first distances between the N sampling points on the first row of the surface of the detection plate 1 and the measuring probe. Then, when the N sampling points on the second row of the surface of the detection plate 1 adsorbed on the surface of the loading platform 41 are moved to the position directly below the measuring probe (not shown) of the non-contact height measuring device 3, the processor 2 enables the non-contact height measuring device 3 to scan and measure the first distances between the N sampling points on the second row of the surface of the detection plate 1 and the measuring probe.

For example, as shown in FIG3 , the non-contact height measuring device 3 measures the first distance corresponding to each sampling point when scanning a row of continuous sampling points on the surface of the test plate 1 adsorbed by the surface of the loading platform 41. The horizontal arrow in FIG3 indicates the scanning direction of the non-contact height measuring device 3.

Thereby, the non-contact height measuring device 3 scans row by row and measures the first distance between the N sampling points in the 3rd to Mth rows on the surface of the detection plate 1, and obtains the first distance corresponding to the sampling points (ie, MxN sampling points).

Therefore, the reference surface profile data can present the height variation of the surface of the detection plate 1 adsorbed by the surface of the carrier platform 41 having the reference state or the predetermined state (also the height variation of the surface of the carrier platform 41 ), as shown in FIG. 3 , for example.

Then, execute step S2 of FIG. 1 to allow the surface of the carrier platform 41 to adsorb the test plate 1. The test plate 1 is taken out of the storage box by a picking mechanism (such as a robot arm) of the semiconductor measurement or detection device 4 and placed on the carrier platform 41.

Next, as shown in step S3 of FIG. 1 , the processor 2 controls the mobile carrier 42 to move the carrier platform 41 relative to the non-contact height measuring device 3 according to the preset moving path. At the same time, the processor 2 controls the non-contact height measuring device 3 to scan and measure a second distance between the non-contact height measuring device 3 and the detection plate 1 adsorbed on the surface of the carrier platform 41 at each sampling point (i.e., the MxN sampling points mentioned above), and provides the second distance corresponding to the sampling points (i.e., the MxN sampling points) to the processor 2.

Taking FIG. 4 as an example, FIG. 4 shows that when the non-contact height measuring device 3 scans and measures a plurality of continuous sampling points in a row (e.g., the continuous sampling points in the same row as shown in FIG. 3 ) on the surface of the detection plate 1 adsorbed by the surface of the carrier platform 41, when some particles on the surface of the carrier platform 41 (e.g., the first and third particles in FIG. 4 ) do not fall on the sampling points but fall beside or near the sampling points, the detection plate 1 will amplify the particles, so that the range of the particles is expanded and extended to the sampling points falling beside or near the particles, and when the sampling points beside or near the particles are scanned by the non-contact height measuring device 3 and the corresponding second distances are measured, the second distances can reflect or highlight the existence of the particles falling beside or near the sampling points, as shown in FIG. 4 .

It is worth mentioning that, in order to make the time spent on the detection process within a reasonable range and not consume too much detection time, the sampling (scanning) frequency and scanning interval (the distance between two adjacent sampling points) of the non-contact height measuring device 3 need to be reasonably planned, so the sampling frequency cannot be adjusted too high and the scanning interval cannot be reduced to a very small value. In this case, some sampling points of the non-contact height measuring device 3 will not fall on the positions where some particles on the surface of the carrier platform 41 exist. However, in this embodiment, the detection plate 1 adsorbed by the surface of the carrier platform 41 can magnify these particles, so that the range of these particles can be extended to fall into the sampling points next to or nearby and can be sampled by the non-contact height measuring device 3.

Then, as shown in step S4 of FIG. 1 , after the processor 2 receives the second distances transmitted by the non-contact height measuring device 3 , based on the coordinates of the sampling points and the second distances corresponding to the sampling points (i.e., MxN sampling points), generates a surface profile data to be measured including the sampling points (coordinates) and the second distances corresponding thereto. The surface profile data to be measured presents the height change of the surface of the detection plate 1 adsorbed by the surface of the carrier platform 41 (also the height change of the surface of the carrier platform 41 to be measured), as shown in FIG. 4 .

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

Specifically, as shown in FIG5 , for example, the processor 2 subtracts the first distance corresponding to the sampling points included in the reference surface data (for example, the continuous sampling points in the same row as shown in FIG3 ) from the second distance corresponding to the sampling points included in the surface profile data to be measured (for example, the continuous sampling points in a row shown in FIG3 ), and obtains a surface profile difference data including the sampling points and a corresponding gap as shown in FIG5 . Then, the processor 2 determines whether the difference corresponding to one or some sampling points in the surface profile difference data is greater than a critical value (dashed line in FIG. 5 ). If so, it determines that particles (such as the three large black dots shown in FIG. 5 ) exist on the surface of the carrier platform 41 at the one or some sampling points (such as the four sampling points circled in FIG. 5 ), and generates the detection result, which shows that particles exist on the surface of the carrier platform 41 and need to be cleaned. After completing the above detection action and being cleaned, the detection plate 1 is put back into the storage box.

In addition, in order to prove that the present embodiment has a better particle detection capability, as shown in FIG6, another reference surface profile data including the sampling points (coordinates) and the third distances corresponding thereto is obtained by the above method. The third distances are generated by the non-contact height measuring device 3 scanning the surface of the carrier platform 41 having the reference state or the predetermined state without adsorbing the detection plate 1 as the above sampling points and measuring the distances between the non-contact height measuring device 3 and each of the sampling points, as shown in FIG6 (FIG6 shows a continuous multi-coordinate image of the same row as FIG3). 7 ); then, as shown in FIG. 7 , the non-contact height measuring device 3 is used to scan the above-mentioned sampling points on the surface of the carrier platform 41 to be tested that is not adsorbed with the test plate 1 (i.e., the surface adhering to the particles 411 as shown in FIG. 4 ) and measure a fourth distance between it and each of the sampling points, and the processor 2 generates another surface profile data to be tested that includes the sampling points (coordinates) and the corresponding fourth distance, as shown in FIG. 7 (FIG. 7 shows the fourth distance of a plurality of consecutive sampling points in the same row as shown in FIG. 3 ).

As shown in FIG8 , the processor 2 obtains another surface profile difference data by subtracting the other surface profile data to be measured from the other reference surface profile data. The processor 2 also determines whether the difference corresponding to one or some sampling points in the other surface profile difference data is greater than the other critical value according to another critical value (the dotted line in FIG8 ), so as to determine whether particles exist at the one or some sampling points. In this case, only one of the continuous sampling points shown in FIG8 has particles. The difference at one sampling point is greater than the other critical value, so that the processor 2 can only determine that there is a particle at one sampling point (e.g., the one circled sampling point in FIG8 ) (e.g., the one large black dot in the middle corresponding to the circled sampling point in FIG8 ), while the other two particles that fall beside or near the sampling point (e.g., the two large black dots on the left and right in FIG8 ) cannot be detected by the non-contact height measuring device 3 because they do not fall at the sampling point position. The other critical value is basically the critical value of the present embodiment minus the thickness of the detection plate 1, but is not limited thereto, and the critical value of the present embodiment is basically determined based on experimental results.

It can be seen that the present embodiment can indeed improve the ability to detect particles on the surface of the carrier platform 41 by adsorbing the detection plate 1 on the surface of the carrier platform 41 and then scanning and measuring the height (profile) of the surface of the detection plate 1.

In summary, the above-mentioned embodiment obtains the reference surface profile data consisting of the heights of multiple sampling points on the surface of the detection plate 1 adsorbed by the surface of the carrier platform 41 having the reference state or the predetermined state (i.e., the first distance) and obtains the heights of the sampling points on the surface of the detection plate 1 adsorbed by the surface of the carrier platform 41 to be tested (i.e., the second distance) The surface profile data to be tested is formed, and according to the gap between the surface profile data to be tested and the reference surface profile data, it is judged whether there are particles on the surface of the carrier platform 41 to be tested, and the detection capability of particles on the surface of the carrier platform 41 is improved, thereby achieving the effect and purpose of the present invention.

However, the above is only an example of the implementation of the present invention, and it should not be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

1: Test plate 2: Processor 3: Non-contact height measurement device 4: Semiconductor measurement or testing equipment 41: Loading platform 411: Particles 42: Mobile carrier S1~S5: Steps

Other features and functions of the present invention will be clearly shown in the implementation method with reference to the drawings, wherein: FIG. 1 is the main process steps of an embodiment of the method for detecting the surface state of the loading platform of the present invention; FIG. 2 is a schematic diagram of the main component blocks included in an embodiment of the system for detecting the surface state of the loading platform of the present invention; FIG. 3 shows that the non-contact height measuring device of the present embodiment scans a plurality of sampling points on the surface of the detection plate adsorbed by the surface of the loading platform having a reference state or a predetermined state and measures the first distance between the non-contact height measuring device and each sampling point; FIG. 4 shows that the non-contact height measuring device of the present embodiment scans the same sampling points as shown in FIG. 3 on the surface of the detection plate adsorbed by the surface of the loading platform to be tested and measures the second distance between the non-contact height measuring device and each sampling point; FIG5 shows the gaps corresponding to the sampling points obtained by subtracting the first distances corresponding to the sampling points shown in FIG3 from the second distances corresponding to the sampling points shown in FIG4; FIG6 shows the third distance between the sampling points and each sampling point measured by the non-contact height measuring device of the present embodiment scanning the same sampling points as shown in FIG3 on the surface of the loading platform to be measured having a reference state or a predetermined state; FIG7 shows the fourth distance between the non-contact height measuring device of the present embodiment scanning the same sampling points as shown in FIG3 on the surface of the loading platform to be measured; and FIG8 shows the gaps corresponding to the sampling points obtained by subtracting the third distances corresponding to the sampling points shown in FIG6 from the fourth distance corresponding to the sampling points shown in FIG7.

S1~S5: Steps

Claims (8)

A method for detecting the surface state of a loading platform comprises: a processor obtains a reference surface profile data, the reference surface profile data comprising a plurality of first distances corresponding to a plurality of sampling points on the surface of a loading platform; the loading platform surface adsorbs a detection plate; the processor controls a non-contact height measuring device to scan the detection plate adsorbed on the loading platform surface and measures a second distance between the detection plate and the detection plate at each of the sampling points; the processor generates a plurality of first distances corresponding to the sampling points and the second distances corresponding to the sampling points according to the second distances provided by the non-contact height measuring device; The surface profile data to be measured; and the processor determines whether there are particles on the surface of the carrier platform and generates a detection result according to the difference between the first distance corresponding to the sampling points included in the reference surface profile data and the second distance corresponding to the sampling points included in the surface profile data to be measured; wherein, when the processor determines that the difference between the first distance and the second distance corresponding to a sampling point corresponding to the reference surface profile data and the surface profile data to be measured is greater than a critical value, the processor determines that there are particles on the surface of the carrier platform at the sampling point. The method for detecting the surface state of a carrier platform as described in claim 1, wherein the carrier platform is placed on a mobile carrier, and the mobile carrier is controlled by the processor to drive the carrier platform to move relative to the non-contact height measuring device according to a preset moving path, and the processor controls the non-contact height measuring device to scan and measure the second distance between it and the detection plate at each sampling point. The method for detecting the surface state of a carrier platform as described in claim 1, wherein 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 detection plate adsorbed by the surface of the carrier platform having a reference state or a predetermined state and measuring the distance between the detection plate and the detection plate at each sampling point, wherein the reference state refers to a state where there are no particles on the surface of the carrier platform, and the predetermined state refers to a state where there are no particles on the surface of the carrier platform or a state where there are some particles that cannot be eliminated on the surface of the carrier platform. A method for detecting the surface state of a carrier platform as described in any one of claims 1 to 3, wherein 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. A surface state detection system for a carrier platform includes: a processor, which obtains a reference surface profile data, the reference surface profile data includes a plurality of first distances corresponding to a plurality of sampling points on a carrier platform surface; a detection plate, which is adsorbed by the carrier platform surface; and a non-contact height measuring device, which is electrically connected to the processor and controlled by the processor; wherein the processor controls the non-contact height measuring device to scan the detection plate adsorbed by the carrier platform surface and measure a second distance between the detection plate and the detection plate at each sampling point; the processor generates a second distance according to the second distances provided by the non-contact height measuring device. Generate a surface profile data to be tested that includes the sampling points and the corresponding second distances; the processor determines whether there are particles on the surface of the carrier platform and generates a detection result according to the difference between the first distance corresponding to the sampling points included in the reference surface profile data and the second distance corresponding to the sampling points included in the surface profile data to be tested; wherein, when the processor determines that the difference between the first distance and the second distance corresponding to a corresponding sampling point in the reference surface profile data and the surface profile data to be tested is greater than a critical value, the processor determines that there are particles on the surface of the carrier platform at the sampling point. As described in claim 5, the carrier surface state detection system, wherein the carrier is placed on a mobile carrier, the mobile carrier is controlled by the processor to drive the carrier relative to the non-contact height measuring device according to a preset moving path, and the processor controls the non-contact height measuring device to scan and measure the second distance between it and the detection plate at each sampling point. The surface state detection system of the carrier platform as described in claim 5, wherein 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 detection plate adsorbed by the surface of the carrier platform having a reference state or a predetermined state and measuring the distance between the detection plate and the detection plate at each sampling point, wherein the reference state refers to a state where there are no particles on the surface of the carrier platform, and the predetermined state refers to a state where there are no particles on the surface of the carrier platform or a state where there are some particles that cannot be eliminated on the surface of the carrier platform. A carrier surface state detection system as described in any one of claims 5 to 7, wherein 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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