Automatic teaching system for feeding position of wafer robot

Abstract

The invention relates to the technical field of wafer carrying robots, in particular to a wafer robot feeding position automatic teaching system which comprises a wafer clamp and a visual system, a wafer carrying arm is arranged on one side of the wafer clamp, the wafer carrying arm carries a wafer silicon wafer to the wafer clamp, and the visual system is arranged on the wafer clamp. At least three mark points are arranged on the wafer clamp in a central symmetry mode around the center point of the wafer clamp, the mark points are located on the same horizontal plane, a camera is arranged over the wafer clamp, the camera captures and identifies the wafer clamp and the mark points, and the visual system receives data of the camera and processes the data. After the camera captures the mark point on the wafer clamp, data are provided for the visual system, so that the visual system calculates the clamp center position of the wafer clamp according to the position of the mark point, physical position quantification is carried out on the teaching point position, the teaching point position is conveniently and rapidly calibrated, and teaching time is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer handling robots, and in particular to an automatic teaching system for wafer robot loading positions. Background Art

[0002] Wafer handling robots are essential components of current semiconductor automated testing equipment. Their core function is to remove wafers from cassettes, place them sequentially on various test stations, and return them to the cassettes after testing. Currently, when using wafer handling robots to transfer silicon wafers, the robot's operating points must first be taught. This requires the operator to manually teach the robot each operating point using a teach pendant.

[0003] The current method of teaching wafer robot loading positions has the following disadvantages:

[0004] 1. The teaching time is long. Since the teaching point needs to be adjusted manually by adjusting the teaching pendant parameters, the operator must first master the use of the teaching pendant. During the teaching process, it is necessary to constantly verify and observe whether the taught position is qualified, which will result in a lot of teaching time.

[0005] 2. Low teaching accuracy. Manual teaching results in varying degrees of accuracy among different operators. Furthermore, the teaching process relies on visual judgment to determine whether the taught position is correct, without any quantified physical position. Once re-teaching is required, it is difficult to restore the previously taught position.

[0006] 3. The teaching risk is high. During the teaching process, there is a possibility of human input parameter errors, which may cause the wafer to be broken.

[0007] Therefore, in order to solve the above problems, it is necessary to develop an automatic teaching system for wafer robot loading position. Summary of the Invention

[0008] In response to the existing technical problems, the present invention aims to provide a method for using a visual system in conjunction with a camera to perform physical position quantification processing of the center position of the wafer fixture through marking points, automatically calculate the difference between the center position of the fixture and the center position of the wafer, and perform automatic correction, thereby improving teaching efficiency, reducing manual intervention, and improving teaching accuracy.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] A wafer robot loading position automatic teaching system includes a wafer clamp and a vision system, wherein a wafer transport arm is provided on one side of the wafer clamp, and the wafer transport arm transports wafer silicon wafers to the wafer clamp, and at least three marking points are provided on the wafer clamp in a centrally symmetrical shape around its center point, and the marking points are located on the same horizontal plane. A camera is provided directly above the wafer clamp, and the camera captures and identifies the wafer clamp and the marking points. The vision system receives data from the camera and processes it to obtain the clamp center position between the marking points and the wafer center position of the wafer silicon wafer placed on the wafer clamp.

[0011] In the present invention, a visual system capable of receiving and processing data is set up in cooperation with a camera to perform physical position quantification processing and analysis of the center position of the fixture and the center position of the wafer, eliminating the need for manual data input, thereby reducing operational errors and improving teaching accuracy. After the camera captures the mark point on the wafer fixture, it provides data to the visual system, allowing the visual system to calculate the fixture center position of the wafer fixture based on the position of the mark point, so as to quantify the physical position of the teaching point, so as to facilitate rapid calibration of the teaching point and save teaching time.

[0012] As an improvement, the line connecting the four marking points passes through the center of the wafer fixture and is bilaterally symmetrical relative to the center of the wafer fixture.

[0013] Preferably, the visual system recognizes four landmarks through a camera and converts the data into physical coordinates (P1 x , P1 y )、(P2 x , P2 y )、(P3 x , P3 y )、(P4 x , P4 y ), and calculate the physical coordinates of the fixture center position (P0 x , P0 y ), where (P0 x , P0 y ) is calculated as:

[0014]

[0015] Preferably, the visual system identifies the silicon wafer through a camera and obtains the physical coordinates of the center position of the wafer (Pt x , Pt y ), calculate the deviation of the two coordinates (D x , D y ), and obtain the compensation value Dis of the wafer handling arm loading position, where

[0016] (D x , D y ) is calculated as follows: (D x , D y )=(P0 x -Pt x , P0 y -Pt y );

[0017] The calculation formula of Dis is:

[0018] As an improvement, a light source is further provided between the camera and the wafer fixture, and the light source is used to illuminate the wafer fixture and the marking point.

[0019] Preferably, the light sources are distributed in a circular shape above the wafer holder.

[0020] As an improvement, the automatic teaching of the loading position of the visual system includes the following steps:

[0021] S1, the visual system detects the position information of the landmark through the camera;

[0022] S2, calculate the center position of the fixture;

[0023] S3, the wafer handling arm places the silicon wafer on the wafer fixture;

[0024] S4, the visual system identifies the position information of the center position of the wafer through the camera;

[0025] S5. Calculate the loading deviation based on the fixture center position and wafer center position data after physical position quantification;

[0026] S6. Determine whether it meets the teaching accuracy;

[0027] S7. Record the teaching point information that meets the accuracy.

[0028] Preferably, in the step S6, determining whether correction is required, if the loading deviation is less than a preset value, the step S7, recording the teaching position step, is executed.

[0029] Preferably, in the step S6, determining whether correction is required, if the feeding deviation is greater than a preset value, automatic correction is performed.

[0030] Preferably, the automatic correction comprises the following steps:

[0031] T1, the wafer handling arm removes the silicon wafer from the wafer fixture;

[0032] T2. Correct the placement of the wafer transport arm according to the deviation;

[0033] T3. The wafer handling arm places the silicon wafer on the wafer fixture again.

[0034] The beneficial effects of the present invention are:

[0035] (1) In the present invention, a visual system capable of receiving and processing data is provided in conjunction with a camera to perform physical position quantitative processing and analysis of the center position of the fixture and the center position of the wafer, eliminating the need for manual data input, thereby reducing operational errors and improving teaching accuracy.

[0036] (2) In the present invention, a camera is set up to capture the mark points on the wafer fixture and provide data to the visual system, so that the visual system calculates the fixture center position of the wafer fixture according to the position of the mark points, so as to quantify the physical position of the teaching point, so as to quickly calibrate the teaching point and save teaching time.

[0037] (3) In the present invention, when the silicon wafer is placed on the wafer fixture by the wafer transport arm, the vision system captures the center position of the wafer through the camera, and by comparing the coordinate positions of the center position of the fixture and the center position of the wafer, the distance deviation between the placement position and the teaching point is quickly calculated.

[0038] (4) During the automatic teaching operation of the present invention, the wafer handling arm is corrected for the difference through the automatic correction step, and then the wafer silicon wafer is placed again to reduce the deviation between the center position of the fixture and the center position of the chip, thereby adjusting the placement position of the wafer handling arm by repeatedly placing the wafer silicon wafer. In this process, after adding the difference requirement, no manual intervention is required, and the adjustment can be fully automated, thereby quickly and accurately teaching the wafer handling arm the loading position.

[0039] In summary, the present invention not only improves the teaching speed but also improves the teaching accuracy, and also simplifies the technical requirements for operators during the teaching process. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the three-dimensional structure of an automatic teaching system for wafer robot loading positions according to the present invention;

[0041] Figure 2 Schematic diagram of the three-dimensional structure of the wafer clamp of the present invention;

[0042] Figure 3 Schematic diagram of the top view of the center position of the clamp of the present invention;

[0043] Figure 4 Schematic diagram of the top view of the center of the wafer of the present invention;

[0044] Figure 5 Schematic diagram of the top view of the marking point of the present invention;

[0045] Figure 6 Schematic diagram of the top view of the wafer clamp of the present invention;

[0046] Figure 7 This is a flow chart of the automatic teaching steps of the loading position of the present invention.

[0047] Reference numerals in the figure: 1. wafer clamp; 10. wafer transport arm; 2. camera; 3. marker point; 4. light source; 5. vision system; 50. clamp center position; 51. wafer center position. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0051] Example 1: This example aims to solve the problem of high risk of teaching. During the teaching process, there is a possibility of human input parameter errors, which may cause the wafer to be broken. Please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 and Figure 6, a wafer robot loading position automatic teaching system, including a wafer clamp 1 and a vision system 5, a wafer handling arm 10 is provided on one side of the wafer clamp 1, the wafer handling arm 10 carries the wafer silicon wafer to the wafer clamp 1, and at least three marking points 3 are provided on the wafer clamp 1 in a centrally symmetrical shape around its center point, and the marking points 3 are located on the same horizontal plane, and a camera 2 is provided directly above the wafer clamp 1, and the camera 2 captures and identifies the wafer clamp 1 and the marking points 3. The vision system 5 receives the data from the camera 2 and processes it to obtain the clamp center position 50 between the marking points 3 and the wafer center position 51 of the wafer silicon wafer placed on the wafer clamp 1, and a light source 4 is further provided between the camera 2 and the wafer clamp 1, and the light source 4 is used to illuminate the wafer clamp 1 and the marking points 3, and the light source 4 is distributed in a circular ring shape above the wafer clamp 1.

[0052] In this embodiment: the visual system 5 cooperates with the camera 2 to quantify the physical position of the clamp center position 50 of the wafer clamp 1 and the chip center position 51 of the wafer silicon wafer placed on the wafer clamp 1, and replaces the steps of using human eye comparison in the existing technology by calculating the difference with physical coordinates, thereby improving the teaching accuracy, and cooperates with the wafer handling arm 10 to automatically teach the loading position, thereby improving the teaching efficiency. In the teaching system of the loading position, there is no need to manually input parameters, only the deviation accuracy requirements need to be set, thereby reducing the teaching error.

[0053] Example 2: This example aims to solve the problem that the teaching process is based on the human eye to judge whether the teaching position is correct, there is no quantitative teaching accuracy result, and once re-teaching is required, it is difficult to restore the previous teaching position. This example is an improvement based on Example 1. For details, please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 The line connecting the four marking points 3 passes through the center of the wafer fixture 1 and is bilaterally symmetrical relative to the center of the wafer fixture 1. The visual system 5 recognizes the four marking points 3 through the camera 2 and converts the data into physical coordinates (P1 x , P1 y )、(P2 x , P2 y )、(P3 x , P3 y )、(P4 x , P4 y ), and calculate the physical coordinates of the fixture center position 50 (P0 x , P0 y ), where (P0x , P0 y ) is calculated as:

[0054]

[0055] The visual system 5 identifies the silicon wafer through the camera 2 and obtains the physical coordinates (Pt x , Pt y ), calculate the deviation of the two coordinates (D x , D y ), and obtain the compensation value Dis of the loading position of the wafer transport arm 10, where

[0056] (D x , D y ) is calculated as follows: (D x , D y )=P0 x -Pt x , P0 y -Pt y );

[0057] The calculation formula of Dis is:

[0058] In this embodiment, the visual system 5 can detect the position of the mark point 3, and the center position between multiple mark points 3 is the clamp center position 50 of the wafer clamp 1 to determine the target position of the wafer handling arm 10 for loading the wafer silicon wafer. At the same time, the visual system 5 can also capture the position of the wafer silicon wafer in the field of view through the camera 2, and calculate the deviation value between the chip center position 51 of the wafer silicon wafer and the clamp center position 50, so as to achieve the purpose of quantitative teaching data of the physical position. The visual system 5 can also process this difference into a compensation value Dis to correct the loading position of the wafer handling arm 10, thereby improving the teaching accuracy.

[0059] It should be noted that: in order to simplify the calculation formula and improve the calculation efficiency of the visual system 5, in this embodiment, four centrally symmetrical marking points 3 are used, and the lines connecting the marking points 3 form an intersection, which is the center position 50 of the fixture, thereby simplifying the calculation formula and improving the teaching efficiency.

[0060] Example 3: This example aims to solve the problem that the operator needs to first master the use of the teaching pendant, and needs to constantly verify and observe whether the taught position is qualified during the teaching process, which leads to a lot of time consumption. This example is an improvement made on the basis of Example 1. For details, please refer to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4、 Figure 5 、 Figure 6 and Figure 7 The automatic teaching of the loading position of the visual system 5 includes the following steps:

[0061] S1, the visual system 5 detects the position information of the marker point 3 through the camera 2;

[0062] S2, calculate the center position of the fixture 50;

[0063] S3, the wafer transport arm 10 places the silicon wafer on the wafer clamp 1;

[0064] S4, the visual system 5 identifies the position information of the wafer center position 51 through the camera 2;

[0065] S5, calculating the loading deviation based on the fixture center position 50 and the wafer center position 51 data after quantification of the physical position;

[0066] S6. Determine whether it meets the teaching accuracy;

[0067] S7. Record the teaching point information that meets the accuracy;

[0068] Automatic remediation involves the following steps:

[0069] T1, the wafer handling arm 10 removes the silicon wafer from the wafer clamp 1;

[0070] T2. Correct the placement position of the wafer transport arm 10 according to the deviation;

[0071] T3 , the wafer transport arm 10 places the silicon wafer on the wafer clamp 1 again.

[0072] If the feeding deviation is less than the preset value, step S7 is executed to record the teaching position step. In step S6, it is determined whether correction is required. If the feeding deviation is greater than the preset value, automatic correction is performed.

[0073] In this embodiment: S6, when determining whether correction is required, the loading position deviation of the wafer transport arm 10 is different according to the production process requirements, such as teaching a rough point position, that is, within 5 mm, and precise teaching requires a deviation within 0.5 mm;

[0074] For example, if the process requirement is that the feeding position deviation is less than 1mm, D x 、D y If the teaching requirements are all less than 0.1mm, then S7 can be performed to record the teaching point information that meets the accuracy. If the requirements are not met, the automatic correction step should be entered. After the wafer transport arm 10 is corrected according to Dis, the loading position deviation is calculated again until D x 、D yAll meet the requirement that the loading position deviation is less than 1mm.

Claims

1. A wafer robot loading position automatic teaching system, comprising a wafer clamp (1) and a visual system (5), wherein a wafer handling arm (10) is provided on one side of the wafer clamp (1), and the wafer handling arm (10) carries a silicon wafer to the wafer clamp (1), characterized in that: At least three marking points (3) are provided on the wafer clamp (1) in a centrally symmetrical manner around its center point, and the marking points (3) are located on the same horizontal plane. A camera (2) is provided directly above the wafer clamp (1), and the camera (2) captures and identifies the wafer clamp (1) and the marking points (3); The vision system (5) receives data from the camera (2) and processes it to obtain the center position (50) of the fixture between the marking points (3) and the center position (51) of the wafer placed on the wafer fixture (1).

2. The wafer robot loading position automatic teaching system according to claim 1, characterized in that: The line connecting the four marking points (3) passes through the center of the wafer clamp (1) and is bilaterally symmetrical relative to the center of the wafer clamp (1).

3. The wafer robot loading position automatic teaching system according to claim 2, characterized in that: The visual system (5) identifies four marker points (3) through a camera (2) and converts the data into physical coordinates (P1 x , P1 y )、(P2 x , P2 y )、(P3 x , P3 y )、(P4 x , P4 y ), and calculate the physical coordinates (P0) of the fixture center position (50) x , P0 y ), where (P0 x , P0 y ) is calculated as:

4. The wafer robot loading position automatic teaching system according to claim 3, characterized in that: The visual system (5) identifies the silicon wafer through the camera (2) and obtains the physical coordinates (Pt) of the center position (51) of the wafer. x , Pt y ), calculate the deviation (D x , D y ), and obtain the compensation value Dis of the loading position of the wafer transport arm (10), wherein, (D x , D y ) is calculated as follows: (D x , D y )=(P0 x -Pt x , P0 y -Pt y ); The calculation formula of Dis is:

5. The wafer robot loading position automatic teaching system according to claim 1, characterized in that: A light source (4) is further provided between the camera (2) and the wafer clamp (1), and the light source (4) is used to illuminate the wafer clamp (1) and the marking point (3).

6. The wafer robot loading position automatic teaching system according to claim 5, characterized in that: The light source (4) is distributed in a circular ring shape above the wafer clamp (1).

7. The wafer robot loading position automatic teaching system according to claim 1, characterized in that: The automatic teaching of the loading position of the visual system (5) comprises the following steps: S1, detection landmark (3); S2, calculating the center position of the fixture (50); S3, placing the silicon wafer; S4, identifying the center position of the wafer (51); S5. Calculate the feeding deviation; S6. Determine whether correction is needed; S7. Record the teaching position.

8. The wafer robot loading position automatic teaching system according to claim 7, characterized in that: In the step S6, determining whether correction is required, if the feeding deviation is less than a preset value, step S7 is executed to record the teaching position.

9. The wafer robot loading position automatic teaching system according to claim 7, characterized in that: In the step S6, it is determined whether correction is required. If the feeding deviation is greater than a preset value, automatic correction is performed.

10. The wafer robot loading position automatic teaching system according to claim 9, characterized in that: The automatic correction includes the following steps: T1. Remove the silicon wafer; T2, correcting the wafer transport arm (10) according to the deviation; T3. Place the silicon wafer again.

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