Device and method for automatically positioning and calibrating wafer center

Abstract

The present invention relates to a device and method for automatically positioning and calibrating the center of a wafer. The device comprises a base, a linear sensor, an optical fiber, a sensor fixing seat, a wafer suction cup device, a wafer lifting mechanism, a suction cup rotating mechanism, a first linear motion mechanism and a second linear motion mechanism. The suction cup rotating mechanism is mounted on the first linear motion mechanism to move forward and backward under the drive of the first linear motion mechanism. The wafer suction cup device is mounted on the suction cup rotating mechanism to rotate under the drive of the first linear motion mechanism. A wafer is placed on the wafer suction cup device to support and vacuum-suction the wafer. The wafer lifting mechanism is mounted on the base beside the wafer suction cup device to lift the wafer from the wafer suction cup device when there is a calibration error. The linear sensor and the optical fiber are mounted on the sensor fixing seat. The sensor fixing seat is located beside the wafer and is mounted on the second linear motion mechanism to move forward and backward under the drive of the second linear motion mechanism. The device and method are conducive to quickly and accurately positioning and calibrating the center of the wafer.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer production, and in particular relates to a device and method for automatically positioning and calibrating the center of a wafer. Background Art

[0002] Wafer refers to the silicon wafer used to make silicon semiconductor integrated circuits. It is round in shape. At present, domestic wafer production lines are mainly 8-inch and 12-inch. Now many wafer manufacturers have higher and higher requirements for the automation of equipment, and have put forward very high requirements for the loading speed and position accuracy of wafers during loading. Wafer tilt correction and positioning work are still completed by magnifying and manually adjusting the motor to complete the alignment work. This manual alignment work has many defects, such as cumbersome operation, low accuracy and easy to make mistakes.

[0003] In the existing technology, most of them still use traditional mechanical positioning methods. When analyzing the workpiece positioning scheme, the positioning support point, that is, the concept of "six-point rule", is usually used. When the workpiece is actually positioned in the fixture, it is not the theoretical "point" that contacts the positioning reference surface of the workpiece, but the positioning support "point" is converted into a specific positioning element, that is, positioning is achieved through various types of positioning elements, that is, different positioning forms should be selected according to the specific structural characteristics of the workpiece and the process processing accuracy requirements, such as planes, outer cylindrical surfaces, circular holes, profiles, combined surfaces, etc. There is a notch on the wafer, and the center positioning is achieved through this notch. This traditional mechanical positioning method not only has low positioning accuracy, low efficiency, and slow speed, but also damages the wafer during the clamping and calibration process, which is very backward. There is also a wafer visual inspection and positioning system based on machine vision positioning in the prior art, which realizes the positioning and alignment of the wafer before cutting. This solution designs an online wafer positioning and alignment visual inspection system that integrates image acquisition, data processing, mechanical movement and information display. Although this solution greatly improves the operating speed and positioning accuracy, the requirements for the working environment are also higher. The camera must operate in a stable working environment, and the operating speed and positioning accuracy are not enough. The cost of the equipment is greatly increased, the algorithm is relatively complex, and it is difficult to apply in practice. Summary of the invention

[0004] The object of the present invention is to provide a device and method for automatically positioning and calibrating the center of a wafer, which is conducive to quickly and accurately positioning and calibrating the center of a wafer.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a device for automatically positioning and calibrating the center of a wafer, comprising a base, a linear sensor, an optical fiber, a sensor fixing seat, a wafer suction cup device, a wafer lifting mechanism, a suction cup rotating mechanism, a first linear motion mechanism and a second linear motion mechanism, wherein the first linear motion mechanism is installed in the base, the suction cup rotating mechanism is installed on the first linear motion mechanism to move back and forth under the drive of the first linear motion mechanism, the wafer suction cup device is installed on the suction cup rotating mechanism to rotate under the drive of the first linear motion mechanism, a wafer is placed on the wafer suction cup device to support and vacuum-suction the wafer, the wafer lifting mechanism is installed on the base beside the wafer suction cup device to lift the wafer from the wafer suction cup device when there is a calibration error, the linear sensor and the optical fiber are installed on the sensor fixing seat, the second linear motion mechanism is installed in the base, the sensor fixing seat is located beside the wafer and is installed on the second linear motion mechanism to move back and forth under the drive of the second linear motion mechanism.

[0006] Furthermore, the sensor fixing base is a U-shaped structure with a lateral notch to allow the wafer to extend therein, and the linear sensor adopts a laser sensor, which is mainly composed of a light projector and a light receiver. The light projector is installed on the upper part of the sensor fixing base, and the light receiver is correspondingly installed on the lower part of the sensor fixing base, so that during the rotation of the wafer, the center deviation of the wafer can be calculated by the change of the linear sensor output; the optical fiber is installed on the upper part of the sensor fixing base, and its light beam is irradiated vertically downward on the wafer, so as to find the position of the wafer notch during the rotation of the wafer.

[0007] Furthermore, the first linear motion mechanism is a first electric cylinder mechanism driven by a first motor, and the suction cup rotation mechanism is installed on the slide of the first electric cylinder mechanism so as to move back and forth under the drive of the first electric cylinder mechanism, thereby adjusting the position of the suction cup rotation mechanism and the center of the wafer suction cup device; the second linear motion mechanism is a second electric cylinder mechanism driven by a second motor, and the sensor fixing seat is installed on the slide of the second electric cylinder mechanism so as to move back and forth under the drive of the second electric cylinder mechanism, thereby adjusting the distance between the sensor fixing seat and the wafer suction cup device, thereby adapting to wafers of different sizes.

[0008] Furthermore, the first linear motion mechanism and the second linear motion mechanism are respectively provided with photoelectric sensors to detect the stroke of the slide thereon to prevent the slide from moving beyond the stroke and causing collision.

[0009] Furthermore, the suction cup rotating mechanism is mainly composed of a third motor and a rotating seat driven to rotate by the third motor, and the wafer suction cup device is installed on the rotating seat.

[0010] Furthermore, the wafer lifting mechanism is mainly composed of a fourth motor, a cam mechanism and a lifting rod. The fourth motor drives the cam mechanism to rotate, and the lower part of the lifting rod, which can only move vertically under the guidance, contacts the cam mechanism to move up and down under the drive of the cam mechanism.

[0011] Furthermore, the wafer suction cup device generates vacuum through a vacuum pump to firmly hold the wafer.

[0012] Furthermore, it also includes a control device, which is arranged in the base, and the input end of the control device is respectively connected to the linear sensor and the optical fiber, and the output end is respectively connected to the drive units of the wafer suction cup device, the wafer lifting mechanism, the suction cup rotation mechanism, the first linear motion mechanism and the second linear motion mechanism to control the operation of various parts of the device.

[0013] The present invention also provides a method for automatically positioning and calibrating the center of a wafer using the above device, comprising the following steps:

[0014] Placing the wafer on the wafer suction cup device, controlling the wafer suction cup device to work, and vacuum sucking the wafer;

[0015] The suction cup rotation mechanism is controlled to work, and the wafer suction cup device and the wafer thereon are driven to rotate one circle. The linear sensor on the sensor fixing seat outputs the acquired data to the control device, and the control device processes the acquired data to obtain the wafer center deviation data;

[0016] The center position of the wafer is found according to the wafer center deviation data, and then the suction cup rotation mechanism is controlled to work to rotate the wafer center to a position where the line connecting the wafer center and the center of the wafer suction cup device and its forward and backward movement direction coincide;

[0017] Control the wafer suction cup device to turn off the vacuum, then control the wafer lifting mechanism to rise and lift the wafer, so that the wafer is separated from the wafer suction cup device, and then control the first linear motion mechanism to work, drive the suction cup rotating mechanism and the wafer suction cup device thereon to move to the center of the wafer, and then control the wafer lifting mechanism to descend, so that the wafer descends onto the wafer suction cup device;

[0018] Control the wafer suction cup device to work, vacuum suck the wafer, and then control the first linear motion mechanism to move in the opposite direction, driving the suction cup rotating mechanism and the wafer suction cup device thereon to move to the original position, and thus the wafer center error correction is completed;

[0019] Control the suction cup rotation mechanism to drive the wafer suction cup device and the wafer on it to rotate, find the wafer notch through the optical fiber on the sensor fixing seat, and then rotate the wafer to any angle. At this point, the wafer center positioning and correction are completed.

[0020] Compared with the prior art, the present invention has the following beneficial effects: the device and method overcome the problems of low positioning accuracy, slow speed, poor stability and possible damage to the wafer in the prior art, not only greatly improve the wafer center positioning accuracy, but also have a high degree of automation, stable and reliable operation, low implementation cost, and can be applied to wafers of different sizes, with fast positioning and correction speed and no damage to the wafer. The device is applicable to any equipment for processing wafers, and completes wafer center positioning and correction before and after processing to meet the needs of wafer production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a side view of the device structure of an embodiment of the present invention.

[0022] Figure 2 4 is a top view of the device structure of an embodiment of the present invention.

[0023] In the figure: 1-base, 2-linear sensor, 3-optical fiber, 4-sensor fixing seat, 5-wafer suction cup device, 6-wafer lifting mechanism, 7-suction cup rotating mechanism, 8-first linear motion mechanism, 9-second linear motion mechanism, 10-wafer. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0025] like Figure 1-2 As shown, the present invention provides a device for automatically positioning and calibrating the center of a wafer, comprising a base 1, a linear sensor 2, an optical fiber 3, a sensor fixing seat 4, a wafer suction cup device 5, a wafer lifting mechanism 6, a suction cup rotating mechanism 7, a first linear motion mechanism 8 and a second linear motion mechanism 9, wherein the first linear motion mechanism 8 is installed in the base 1, the suction cup rotating mechanism 7 is installed on the first linear motion mechanism 8 to move forward and backward under the drive thereof, the wafer suction cup device 5 is installed on the suction cup rotating mechanism 7 to rotate under the drive thereof, a wafer 10 is placed on the wafer suction cup device 5 to support and vacuum-suction the wafer 10, the wafer lifting mechanism 6 is installed on the base 1 beside the wafer suction cup device 5 to lift the wafer 10 from the wafer suction cup device 5 when there is a calibration error, the linear sensor 2 and the optical fiber 3 are installed on the sensor fixing seat 4, the second linear motion mechanism 9 is installed in the base 1, the sensor fixing seat 4 is located beside the wafer and is installed on the second linear motion mechanism 9 to move forward and backward under the drive thereof.

[0026] In this embodiment, the sensor holder 4 is a U-shaped structure with a lateral notch to allow the wafer to extend therein, and the linear sensor 2 adopts a laser sensor, which is mainly composed of a light projector and a light receiver. The light projector is installed on the upper part of the sensor holder, and the light receiver is correspondingly installed on the lower part of the sensor holder. During the rotation of the wafer, the voltage or current analog quantity output by the linear laser sensor will change. According to this change, the control device can calculate the center error of the wafer. The optical fiber 3 is installed on the upper part of the sensor holder 4, and its light beam is vertically irradiated downward on the wafer to find the position of the wafer notch during the rotation of the wafer.

[0027] In this embodiment, the first linear motion mechanism 8 is a first electric cylinder mechanism driven by a first motor, and the suction cup rotating mechanism is installed on the slide of the first electric cylinder mechanism to move forward and backward under the drive of the first electric cylinder mechanism, thereby adjusting the position of the suction cup rotating mechanism and the center of the wafer suction cup device. The second linear motion mechanism 9 is a second electric cylinder mechanism driven by a second motor, and the sensor fixing seat is installed on the slide of the second electric cylinder mechanism to move forward and backward under the drive of the second electric cylinder mechanism, thereby adjusting the distance between the sensor fixing seat and the wafer suction cup device, thereby adapting to wafers of different sizes. Photoelectric sensors are respectively provided on the first linear motion mechanism 8 and the second linear motion mechanism 9 to detect the stroke of the slide thereon to prevent the slide from moving beyond the stroke and causing collision.

[0028] The suction cup rotating mechanism 7 is mainly composed of a third motor and a rotating seat driven to rotate by the third motor, and the wafer suction cup device is installed on the rotating seat.

[0029] The wafer lifting mechanism 6 is mainly composed of a fourth motor, a cam mechanism and a lifting rod. The fourth motor drives the cam mechanism to rotate, and the lower part of the lifting rod, which can only move vertically under the guidance, contacts the cam mechanism to move up and down under the drive of the cam mechanism. The use of the cam mechanism can greatly reduce the noise when the wafer lifting mechanism lifts and lowers the wafer. The structure is more stable and reliable and saves space.

[0030] The wafer suction cup device 5 generates vacuum through a vacuum pump to firmly hold the wafer.

[0031] In order to realize automatic control of the device, the device is also provided with a control device, which is arranged in the base. The input end of the control device is respectively connected to the linear sensor and the optical fiber, and the output end is respectively connected to the drive units of the wafer suction cup device, the wafer lifting mechanism, the suction cup rotation mechanism, the first linear motion mechanism and the second linear motion mechanism to control the operation of various parts of the device.

[0032] Based on the above device, the present invention also provides a method for automatically positioning and calibrating the center of a wafer, comprising the following steps:

[0033] 1) Place the wafer on the wafer suction cup device, control the wafer suction cup device to work, and vacuum suck the wafer.

[0034] 2) Control the suction cup rotation mechanism to drive the wafer suction cup device and the wafer on it to rotate one circle. The linear sensor on the sensor holder outputs the acquired data to the control device, which processes the acquired data to obtain the wafer center deviation data. The linear sensor obtains a voltage or current analog quantity. When the wafer rotates one circle, the control device can calculate the wafer center deviation data based on the change of the analog quantity data.

[0035] 3) Find the wafer center position according to the wafer center deviation data, and then control the suction cup rotation mechanism to rotate the wafer center to the position where the line connecting the wafer center and the center of the wafer suction cup device coincides with its forward and backward movement direction.

[0036] 4) Control the wafer suction cup device to turn off the vacuum, then control the wafer lifting mechanism to rise and lift the wafer, so that the wafer is separated from the wafer suction cup device, and then control the first linear motion mechanism to work, drive the suction cup rotation mechanism and the wafer suction cup device thereon to move to the center of the wafer, and then control the wafer lifting mechanism to descend, so that the wafer descends onto the wafer suction cup device.

[0037] 5) Control the wafer suction cup device to work, vacuum suck the wafer, and then control the first linear motion mechanism to move in the opposite direction, driving the suction cup rotation mechanism and the wafer suction cup device thereon to move to the original position. At this point, the wafer center error correction is completed.

[0038] 6) Control the suction cup rotation mechanism to drive the wafer suction cup device and the wafer on it to rotate, find the wafer notch through the optical fiber on the sensor fixing seat, and rotate the wafer to any angle. At this point, the wafer center positioning and correction are completed.

[0039] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A device for automatically positioning and calibrating the center of a wafer, characterized in that: It includes a base, a linear sensor, an optical fiber, a sensor fixing seat, a wafer suction cup device, a wafer lifting mechanism, a suction cup rotating mechanism, a first linear motion mechanism and a second linear motion mechanism, wherein the first linear motion mechanism is installed in the base, the suction cup rotating mechanism is installed on the first linear motion mechanism to move forward and backward under the drive of the first linear motion mechanism, the wafer suction cup device is installed on the suction cup rotating mechanism to rotate under the drive of the first linear motion mechanism, a wafer is placed on the wafer suction cup device to support and vacuum suck the wafer, the wafer lifting mechanism is installed on the base beside the wafer suction cup device to lift the wafer from the wafer suction cup device when there is a calibration error, the linear sensor and the optical fiber are installed on the sensor fixing seat, the second linear motion mechanism is installed in the base, the sensor fixing seat is located beside the wafer and installed on the second linear motion mechanism to move forward and backward under the drive of the second linear motion mechanism; The sensor holder is a U-shaped structure with a side notch to allow the wafer to extend therein. The linear sensor adopts a laser sensor, which is mainly composed of a light projector and a light receiver. The light projector is installed on the upper part of the sensor holder, and the light receiver is correspondingly installed on the lower part of the sensor holder, so that during the rotation of the wafer, the center deviation of the wafer can be calculated through the change of the linear sensor output; the optical fiber is installed on the upper part of the sensor holder, and its light beam is vertically irradiated downward on the wafer, so as to find the position of the wafer notch during the rotation of the wafer; The first linear motion mechanism is a first electric cylinder mechanism driven by a first motor, and the suction cup rotating mechanism is installed on the slide of the first electric cylinder mechanism to move forward and backward under the drive of the first electric cylinder mechanism, thereby adjusting the position of the suction cup rotating mechanism and the center of the wafer suction cup device; the second linear motion mechanism is a second electric cylinder mechanism driven by a second motor, and the sensor fixing seat is installed on the slide of the second electric cylinder mechanism to move forward and backward under the drive of the second electric cylinder mechanism, thereby adjusting the distance between the sensor fixing seat and the wafer suction cup device, thereby adapting to wafers of different sizes; the first linear motion mechanism and the second linear motion mechanism are respectively provided with photoelectric sensors to detect the stroke of the slide thereon to avoid collision caused by the slide moving beyond the stroke; The suction cup rotating mechanism is mainly composed of a third motor and a rotating seat driven to rotate by the third motor, and the wafer suction cup device is installed on the rotating seat; The wafer lifting mechanism is mainly composed of a fourth motor, a cam mechanism and a lifting rod. The fourth motor drives the cam mechanism to rotate, and the lower part of the lifting rod, which can only move vertically under the guidance, contacts the cam mechanism to move up and down under the drive of the cam mechanism. The wafer suction cup device generates vacuum through a vacuum pump to firmly suck the wafer; It also includes a control device, which is arranged in the base, and the input end of the control device is respectively connected to the linear sensor and the optical fiber, and the output end is respectively connected to the drive unit of the wafer suction cup device, the wafer lifting mechanism, the suction cup rotation mechanism, the first linear motion mechanism and the second linear motion mechanism, so as to control the operation of various parts of the device; The method for automatically positioning and calibrating the center of a wafer using the device comprises the following steps: Placing the wafer on the wafer suction cup device, controlling the wafer suction cup device to work, and vacuum sucking the wafer; The suction cup rotation mechanism is controlled to work, and the wafer suction cup device and the wafer thereon are driven to rotate one circle. The linear sensor on the sensor fixing seat outputs the acquired data to the control device, and the control device processes the acquired data to obtain the wafer center deviation data; The center position of the wafer is found according to the wafer center deviation data, and then the suction cup rotation mechanism is controlled to work to rotate the wafer center to a position where the line connecting the wafer center and the center of the wafer suction cup device and its forward and backward movement direction coincide; Control the wafer suction cup device to turn off the vacuum, then control the wafer lifting mechanism to rise and lift the wafer, so that the wafer is separated from the wafer suction cup device, and then control the first linear motion mechanism to work, drive the suction cup rotating mechanism and the wafer suction cup device thereon to move to the center of the wafer, and then control the wafer lifting mechanism to descend, so that the wafer descends onto the wafer suction cup device; Control the wafer suction cup device to work, vacuum suck the wafer, and then control the first linear motion mechanism to move in the opposite direction, driving the suction cup rotating mechanism and the wafer suction cup device thereon to move to the original position, and thus the wafer center error correction is completed; Control the suction cup rotation mechanism to drive the wafer suction cup device and the wafer on it to rotate, find the wafer notch through the optical fiber on the sensor fixing seat, and then rotate the wafer to any angle. At this point, the wafer center positioning and correction are completed.

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