[0017] Such as figure 1 The shown automatic positioning device for semiconductor wafers includes three parts: a vision system, a multi-directional moving platform and a test probe. The vision system in the present invention includes a camera, a microscope, and a light source; the vision system is used for extracting wafer image features. The multi-directional mobile platform includes Y, X, Z, and θ platforms, and a wafer table 4 installed on the θ platform; the multi-directional mobile platform is used to control wafer movement. The test probe is used to achieve contact with the wafer. In the vision system of the present invention, the front end of the imaging lens of the camera 1 is installed with the microscope 2 and the light source 3 in sequence, and the camera 1 is installed on the frame 11. In the present invention, the test probe 8 is aligned and contacted with the wafer 5, the test probe 8 is integrally installed on the frame 11 of the vision system, and the back end of the test probe 8 is electrically connected to an external tester for sending to the subsequent tester. Prepare the hardware for receiving the signal. The θ platform 6 in the multi-directional mobile platform of the present invention is installed on the Z platform 9 (Z platform 9 is a pneumatic platform), the Z platform 9 is installed on the X platform 7, and the X platform 7 is installed on Y platform 10. The θ platform 6 described in this embodiment includes a motor 12 and is connected to the θ platform 6 through a belt (not marked in the figure) or a gear. The slide table 4 described in this embodiment is provided with an exhaust hole inside, which is connected to a vacuum negative pressure device through an exhaust hose, and the 4 slides are evacuated, and the wafer 5 is adsorbed on the slide table 4 for storage It is fixed in close contact with the platform 4. The X platform 7 described in this embodiment includes an X rail sliding seat, on which a screw rod is connected to the motor 13, and the screw rod is connected to an X sliding table with a nut. The Y platform 10 described in this embodiment includes a Y track sliding seat on which a screw is connected to the motor 14 and is connected to a Y sliding table with a nut through the screw.
[0018] The structures of the Y platform, X platform, Z platform, and θ platform involved in the above-mentioned multi-directional mobile platform belong to conventional technologies. For example, the related track slides, screw rods and nuts are matched, so specific labels and descriptions are omitted.
[0019] In the present invention, the Y platform 10 is placed at the bottom of the entire mobile platform and is responsible for the wafer 5 line-changing action. It has the largest load and requires the least actions to ensure the efficiency, accuracy and stability of the platform; the X platform 7 is on the Y platform 10 , Responsible for the movement of the wafer 5 in the column direction; Z platform 9 is responsible for the up and down movement of the wafer 5; theta platform 6 is responsible for the rotation of the wafer 5 during the alignment process, and the theta platform 6 will not be performed during the test process after the alignment is completed Rotate.
[0020] The automatic positioning device of the present invention first uses the camera 1 to collect image information on the wafer 5 placed on the wafer stage 4 and undergoes a series of processing such as filtering, expansion, corrosion, and binarization to obtain image boundary contour information. Then save the obtained boundary information as template one, measure the deflection angle of template one, and rotate the wafer table 4 to adjust the deflection angle of the wafer 5 to within the required error range. The wafer stage 4 carries the wafer 5 and moves to the vicinity of the test starting point. The camera 1 collects the image of the characteristic area and undergoes a series of processing such as filtering, expansion, corrosion, and binarization to obtain the image boundary contour information of the characteristic area. Select the contour information as template two, and calculate the distance from the template to the test starting point. The wafer stage 4 carries the wafer 5 and moves the test starting point below the test probe 8 to start the test. In subsequent tests, the first wafer of the same specification only needs to do the initial template matching once to realize the automatic alignment of the same specification wafer.
[0021] The vision system in the present invention is responsible for collecting wafer surface image information, and the XY coordinate system of the image taken by the camera 1 is kept parallel to the XY coordinate system of the mobile platform. The slide table 4 is placed on the Z platform 9 and the rotating θ platform 6, and performs vertical movement in the Z direction. The X platform 7 and the Y platform 10 can drive the slide table 4 to move horizontally in the X and Y directions. The θ platform 6 can drive the slide table 4 to rotate in the θ direction. A vacuum suction device is used to suck the wafer 5 onto the wafer carrier 4 through the air holes distributed on the wafer carrier 4 to keep the wafer 5 and the wafer carrier 4 relatively fixed. The movement of the slide table 4 is controlled by the software system to control the drive motor, and the respective motors drive the Y platform, X platform, Z platform and rotating platform θ platform in the multi-directional moving platform. In the present invention, the involved software system includes two parts: a visual imaging processing subsystem and a control subsystem. The vision imaging subsystem is responsible for a series of processing on the wafer image collected by the camera to obtain the coordinates of the binary image and other information; the control subsystem is responsible for transmitting the coordinate information conversion position control data to the driving motor to drive the moving platform and the rotating platform. To complete the entire wafer positioning process. The motor of the mobile platform in the present invention actually includes four motors in the four directions of Y, X, Z, and θ. Responsible for the horizontal movement of the mobile platform in the X and Y directions, the vertical movement in the Z direction, and the rotational movement of the rotating θ platform in the θ direction.
