Wafer positioning system, method and device used in semiconductor manufacturing process

Abstract

The present application provides a wafer positioning system, method and device for use in a semiconductor manufacturing process. In the present application, three photoelectric sensors are provided, and a two-dimensional coordinate system is also set according to the positions of the three photoelectric sensors. The three photoelectric sensors are at equal distances from the origin. After the wafer is placed on a wafer carrying disc, the three photoelectric sensors can be used to determine the point where the edge of the wafer intersects the X-axis and Y-axis of the two-dimensional coordinate system, thereby determining the current center of the wafer. When a notch in the wafer is detected by a photoelectric sensor, the distance between the detected photoelectric sensor and the notch is significantly greater than the distance from other sensors to the edge of the wafer. This principle can be used to determine the location of the notch, thereby obtaining an offset and a deflection angle, and then the wafer grabbing robot arm can be positioned and corrected. The present application is beneficial for improving the yield of semiconductors.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a wafer positioning system, method and device used in a semiconductor manufacturing process. Background Art

[0002] In the semiconductor manufacturing process, precise positioning of wafers is a crucial link. The accuracy and stability of this link directly affect the quality and output of the final semiconductor products. Wafers are usually transported and placed by automated handling equipment, such as overhead crane systems. However, due to various factors in the operation process, such as mechanical vibration, load imbalance or operating errors, the wafers may rotate slightly and shift in position during the transfer process. This movement may cause the orientation of the positioning notch on the wafer to change, which in turn makes it impossible to accurately align the subsequent processing steps, and even causes the wafer to be damaged during the processing process or the packaging cannot be completed correctly, which significantly reduces the yield of the semiconductor.

[0003] At present, although there are many wafer handling and positioning devices on the market, they generally face the problems of insufficient positioning accuracy, poor stability or poor adaptability. Especially in the context of increasing wafer diameter and increasing integration, the requirements for positioning accuracy are becoming increasingly stringent, and existing technical means are difficult to meet the needs of higher standards. Therefore, seeking a positioning method to ensure precise wafer alignment has become a key technical issue for improving the quality of semiconductor products. Summary of the invention

[0004] In view of this, embodiments of the present application provide a wafer positioning system, method and device for use in a semiconductor manufacturing process to improve the yield of semiconductors.

[0005] In a first aspect, an embodiment of the present application provides a wafer positioning system used in a semiconductor manufacturing process, the positioning system comprising a positioning device and a wafer grabbing robot arm, the positioning device comprising: a first photoelectric sensor, a second photoelectric sensor, a third photoelectric sensor, a wafer carrying disc, a servo motor and a processor, the servo motor is used to drive the wafer carrying disc to rotate, the position line of the second photoelectric sensor and the third photoelectric sensor is perpendicular to the X-axis in the three-axis coordinate system corresponding to the wafer grabbing robot arm, the third photoelectric sensor is located on the side close to the wafer grabbing robot arm, the first photoelectric sensor is located on the center line of the second photoelectric sensor and the third photoelectric sensor, in a two-dimensional coordinate system constructed with the center line as the X-axis and the midpoint of the second photoelectric sensor and the third photoelectric sensor as the origin, the coordinates of the first photoelectric sensor are (X1, 0), the coordinates of the second photoelectric sensor are (0, Y1), and the coordinates of the third photoelectric sensor are (0, -Y1), the values ​​corresponding to X1, Y1 and -Y1 are equal and greater than the radius R of the wafer, and the origin of the two-dimensional coordinate system is 1 / 4 of the wafer carrying disc. The centers of the wafer carrier discs overlap, the heights of the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor are the same as the height of the wafer placed on the wafer carrier disc, the wafer grabbing robot arm is used to place the wafer transferred from the upstream process transport rail on the wafer carrier disc, and to grab the wafer on the wafer carrier disc to the downstream process transport rail after positioning is completed, the processor is respectively communicated with the first photoelectric sensor, the second photoelectric sensor, the third photoelectric sensor, the servo motor and the wafer grabbing robot arm, the first photoelectric sensor is used to measure the distance between the edge point on the X-axis of the two-dimensional coordinate system on the side of the wafer close to the first photoelectric sensor and the first photoelectric sensor, the second photoelectric sensor is used to measure the distance between the edge point on the Y-axis of the two-dimensional coordinate system on the side of the wafer close to the second photoelectric sensor and the second photoelectric sensor, and the third photoelectric sensor is used to measure the distance between the edge point on the Y-axis of the two-dimensional coordinate system on the side of the wafer close to the third photoelectric sensor and the third photoelectric sensor.

[0006] Optionally, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0007] Optionally, the processor is a programmable logic controller.

[0008] In a second aspect, an embodiment of the present application provides a method for positioning a wafer in a semiconductor manufacturing process, the positioning method being applied to a positioning system as described in any one of the first aspects, the positioning method running in the processor, and the positioning method comprising:

[0009] After the wafer grabbing robot arm places the wafer on the wafer carrying disc, obtaining a first distance d1 to the edge of the wafer measured by the first photoelectric sensor, a second distance d2 to the edge of the wafer measured by the second photoelectric sensor, and a third distance d3 to the edge of the wafer measured by the third photoelectric sensor;

[0010] Determine, according to the first distance d1, a first coordinate (X1-d1, 0) of a first edge point of the wafer on the side of the wafer close to the first photoelectric sensor and located on the X-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and determine, according to the second distance d2, a second coordinate (0, Y1-d2) of a second edge point of the wafer on the side of the wafer close to the second photoelectric sensor and located on the Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and determine, according to the third distance d3, a third coordinate (0, -(Y1-d3)) of a third edge point of the wafer on the side of the wafer close to the third photoelectric sensor and located on the -Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc;

[0011] The initial center coordinates of the wafer in the two-dimensional coordinate system are calculated according to the following formula: , ):

[0012] ;

[0013] ;

[0014] Determine whether the wafer positioning notch is currently on the Y axis of the two-dimensional coordinate system according to the following target formula:

[0015] ;

[0016] in, is the rotation angle of the wafer supporting disc, when When the target formula is not equal, determining that the positioning notch of the wafer is currently located on the Y axis of the two-dimensional coordinate system;

[0017] According to the following formula, when the rotation angle of the wafer supporting disc is When , the target center coordinates of the wafer in the two-dimensional coordinate system are:

[0018] ;

[0019] ;

[0020] The vector from the target circle center coordinate to the positioning gap is calculated according to the following formula:

[0021] ;

[0022] Wherein, d4 is the rotation angle of the wafer supporting disc. , a fourth distance to the edge of the wafer measured by the third photoelectric sensor;

[0023] The rotation angle of the wafer supporting disc is determined according to the following formula: When The cosine angle between the Y axis and the two-dimensional coordinate system:

[0024] ;

[0025] in, is the unit vector of the Y axis of the two-dimensional coordinate system;

[0026] Control the wafer grabbing robot arm according to the positioning coordinates ( , , Z, a, b, ), positioning and grabbing the wafer;

[0027] Among them, the placement coordinates of the wafer grabbing robot arm are ( , , Z, a, b, ).

[0028] Optionally, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0029] Optionally, the processor is in communication with the negative pressure system, and the method further comprises:

[0030] After the wafer grabbing robot arm places the wafer on the wafer carrying disc, controlling the negative pressure system to generate negative pressure;

[0031] When the wafer grabbing robot arm grabs the wafer on the wafer carrying disc, the negative pressure system is controlled to turn off the negative pressure.

[0032] Optionally, the processor is a programmable logic controller.

[0033] In a third aspect, an embodiment of the present application provides a wafer positioning device used in a semiconductor manufacturing process, wherein the positioning device is applied to the processor of the positioning system as described in any one of the first aspects, and the positioning device includes:

[0034] an acquisition unit, configured to acquire, after the wafer grabbing robot arm places the wafer on the wafer carrying disc, a first distance d1 to the edge of the wafer measured by the first photoelectric sensor, a second distance d2 to the edge of the wafer measured by the second photoelectric sensor, and a third distance d3 to the edge of the wafer measured by the third photoelectric sensor;

[0035] a determining unit, configured to determine, according to the first distance d1, a first coordinate (X1-d1, 0) of a first edge point of the wafer located on the X-axis of the two-dimensional coordinate system on a side of the wafer close to the first photoelectric sensor when the wafer is in an initial state of the wafer carrying disc, and to determine, according to the second distance d2, a second coordinate (0, Y1-d2) of a second edge point of the wafer located on the Y-axis of the two-dimensional coordinate system on a side of the wafer close to the second photoelectric sensor when the wafer is in an initial state of the wafer carrying disc, and to determine, according to the third distance d3, a third coordinate (0, -(Y1-d3)) of a third edge point of the wafer located on the -Y-axis of the two-dimensional coordinate system on a side of the wafer close to the third photoelectric sensor when the wafer is in an initial state of the wafer carrying disc;

[0036] The first calculation unit is used to calculate the initial center coordinates of the wafer in the two-dimensional coordinate system according to the following formula: , ):

[0037] ;

[0038] ;

[0039] The judgment unit determines whether the positioning notch of the wafer is currently on the Y axis of the two-dimensional coordinate system according to the following target formula:

[0040] ;

[0041] in, is the rotation angle of the wafer supporting disc, when When the target formula is not equal, determining that the positioning notch of the wafer is currently located on the Y axis of the two-dimensional coordinate system;

[0042] The second calculation unit is used to calculate the rotation angle of the wafer supporting disc according to the following formula: When , the target center coordinates of the wafer in the two-dimensional coordinate system are:

[0043] ;

[0044] ;

[0045] The third calculation unit is used to calculate the vector from the target circle center coordinate to the positioning gap according to the following formula:

[0046] ;

[0047] Wherein, d4 is the rotation angle of the wafer supporting disc. , a fourth distance to the edge of the wafer measured by the third photoelectric sensor;

[0048] The fourth calculation unit is used to determine the rotation angle of the wafer supporting disc according to the following formula: When The cosine angle between the Y axis and the two-dimensional coordinate system:

[0049] ;

[0050] in, is the unit vector of the Y axis of the two-dimensional coordinate system;

[0051] The first control unit is used to control the wafer grabbing robot arm to position the wafer according to the positioning coordinates ( , , Z, a, b, ), positioning and grabbing the wafer;

[0052] Among them, the placement coordinates of the wafer grabbing robot arm are ( , , Z, a, b, ).

[0053] Optionally, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0054] Optionally, the processor is in communication with the negative pressure system, and the device further comprises:

[0055] The second control unit is used to control the negative pressure system to generate negative pressure after the wafer grasping robot arm places the wafer on the wafer carrying disc; and to control the negative pressure system to turn off the negative pressure when the wafer grasping robot arm grasps the wafer on the wafer carrying disc.

[0056] The technical solution provided by the embodiments of the present application may have the following beneficial effects:

[0057] In the present application, three photoelectric sensors are provided, and a two-dimensional coordinate system is also set according to the positions of the three photoelectric sensors. The distances of the three photoelectric sensors from the origin are equal. After the wafer is placed on the wafer carrying disc, the three photoelectric sensors can be used to determine the point where the edge of the wafer intersects the X-axis and Y-axis of the two-dimensional coordinate system, thereby determining the current center of the wafer. When the notch of the wafer is detected by the photoelectric sensor, the distance between the detected photoelectric sensor and the notch is significantly greater than the distance from other sensors to the edge of the wafer. This principle can be used to determine the position of the notch, thereby obtaining the offset and deflection angle, and then positioning and correcting the wafer grasping robot arm, so that the wafer grasping robot arm uses the corrected data to position and grasp the wafer, so that the position and angle of the wafer when entering the next process are relatively accurate, which is beneficial to improving the yield of semiconductors.

[0058] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A schematic diagram of a wafer positioning system used in a semiconductor manufacturing process provided by an embodiment of the present application;

[0061] Figure 2 A schematic flow chart of a method for positioning a wafer in a semiconductor manufacturing process provided by an embodiment of the present application;

[0062] Figure 3 A schematic structural diagram of a wafer positioning device used in a semiconductor manufacturing process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0064] Figure 1 A schematic diagram of a wafer positioning system for use in a semiconductor manufacturing process provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the positioning system includes a positioning device and a wafer grabbing robot arm, and the positioning device includes: a first photoelectric sensor, a second photoelectric sensor, a third photoelectric sensor, a wafer carrying disc, a servo motor ( Figure 1 not shown) and a processor ( Figure 1, not shown in the figure), the servo motor is used to drive the wafer carrying disc to rotate, the position line of the second photoelectric sensor and the third photoelectric sensor is perpendicular to the X-axis in the three-axis coordinate system corresponding to the wafer grabbing robot arm, the third photoelectric sensor is located on the side close to the wafer grabbing robot arm, the first photoelectric sensor is located on the center line of the second photoelectric sensor and the third photoelectric sensor, in a two-dimensional coordinate system constructed with the center line as the X-axis and the midpoint of the second photoelectric sensor and the third photoelectric sensor as the origin, the coordinates of the first photoelectric sensor are (X1, 0), the coordinates of the second photoelectric sensor are (0, Y1), and the coordinates of the third photoelectric sensor are (0, -Y1), the values ​​corresponding to X1, Y1 and -Y1 are equal and greater than the radius R of the wafer, the origin of the two-dimensional coordinate system overlaps with the center of the wafer carrying disc, and the heights of the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor are equal to the center of the wafer carrying disc. The wafers placed on the wafer carrier disc are of the same height, the wafer grabbing robot arm is used to place the wafers transferred from the transport rail of the upstream process on the wafer carrying disc, and is used to grab the wafers on the wafer carrying disc and put them on the transport rail of the downstream process after positioning is completed, the processor is respectively communicated with the first photoelectric sensor, the second photoelectric sensor, the third photoelectric sensor, the servo motor and the wafer grabbing robot arm, the first photoelectric sensor is used to measure the distance between the edge point of the wafer on the X-axis of the two-dimensional coordinate system on the side close to the first photoelectric sensor and the first photoelectric sensor, the second photoelectric sensor is used to measure the distance between the edge point of the wafer on the Y-axis of the two-dimensional coordinate system on the side close to the second photoelectric sensor and the second photoelectric sensor, and the third photoelectric sensor is used to measure the distance between the edge point of the wafer on the Y-axis of the two-dimensional coordinate system on the side close to the third photoelectric sensor and the third photoelectric sensor.

[0065] Specifically, Figure 1As shown, the positioning device includes a wafer carrying disc, the area of ​​the wafer carrying disc is smaller than the area of ​​the wafer, the wafer carrying disc is used to place the wafer, so that the positioning device can position the wafer to determine the offset and offset angle of the center of the wafer, and three photoelectric sensors are arranged around the wafer carrying disc, namely a first photoelectric sensor, a second photoelectric sensor and a third photoelectric sensor, wherein the third photoelectric sensor is arranged on a side close to the wafer grabbing robot arm, and a line connecting the setting positions of the second photoelectric sensor and the third photoelectric sensor is perpendicular to the X-axis in the three-axis coordinate system corresponding to the wafer grabbing robot arm, and the first photoelectric sensor is arranged on the center line of the second photoelectric sensor and the third photoelectric sensor, that is: the second photoelectric sensor and the third photoelectric sensor are arranged on the Y-axis of the two-dimensional coordinate system, the first photoelectric sensor is arranged on the X-axis of the two-dimensional coordinate system, and the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor are arranged on the X-axis of the two-dimensional coordinate system. The distances between the sensors and the origin of the two-dimensional coordinate system are equal, and the distance is greater than the radius R of the wafer. The origin of the two-dimensional coordinate system overlaps with the center of the wafer carrying disk, that is, the distances between the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor and the center of the wafer carrying disk are equal, that is, the coordinates of the position of the first photoelectric sensor in the two-dimensional coordinate system are (X1, 0), the coordinates of the position of the second photoelectric sensor in the two-dimensional coordinate system are (0, Y1), and the coordinates of the position of the third photoelectric sensor in the two-dimensional coordinate system are (0, -Y1). The values ​​corresponding to X1, Y1 and -Y1 are equal and greater than the radius R of the wafer. The heights of the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor are equal to the height of the wafer after it is placed on the wafer carrying disk. In this way, the light emitted by any photoelectric sensor can be reflected back after being irradiated on the edge of the wafer, thereby obtaining relevant data.

[0066] The servo motor can drive the wafer carrying disc to rotate. Through rotation, the photoelectric sensor can obtain the coordinates of the intersection of the wafer edge and the two-dimensional coordinate system, thereby calculating the motion trajectory of the wafer center and detecting whether the wafer positioning notch is currently in the negative direction of the Y-axis of the two-dimensional coordinate system, thereby determining the offset and offset angle of the wafer center when the wafer positioning notch is currently in the negative direction of the Y-axis of the two-dimensional coordinate system.

[0067] It should be noted that the setting position of the servo motor and the connection method with the wafer carrying disc can be set according to the model and rotation method of the servo motor, and no specific limitation is made here.

[0068] The wafer flows between various processes through the overhead crane system. Before the overhead crane system transfers the wafer from the previous process to the next process, the wafer needs to be placed on the wafer carrying disc by the wafer grasping robot arm for positioning, and then the wafer is grasped according to the positioned coordinates, and then the wafer is placed at the starting position of the next process and transported by the overhead crane system. Before positioning the wafer, the grasping position of the wafer grasping robot arm is (0,0,z,a,b,0), which are expressed as follows: the offset distance on the X-axis when the wafer grasping robot arm grasps the wafer is 0, the offset distance on the Y-axis when the wafer grasping robot arm grasps the wafer is 0, the up and down distance of the wafer grasping robot arm relative to the wafer carrying platform is z, the rotation angle of the wafer grasping robot arm along the X-axis in the three-axis coordinate system is a, the rotation angle of the wafer grasping robot arm along the Y-axis in the three-axis coordinate system is b, and the rotation angle of the C-axis of the wafer grasping robot arm is 0.

[0069] The positioning device also includes a processor. Any photoelectric sensor will send the collected data to the processor so that the processor can control whether the servo motor continues to rotate through the acquired data, and send control instructions to the wafer grabbing robot arm so as to control the wafer grabbing robot arm to grab the wafer according to the positioned coordinates. Furthermore, after the wafer is placed on the wafer carrying disc, the processor controls the servo motor to rotate, and acquires the data collected by the photoelectric sensor according to a preset period. When the processor calculates that the positioning notch of the wafer is in the negative direction of the Y-axis of the two-dimensional coordinate system, it controls the servo motor to stop rotating, and sends control instructions to the wafer grabbing robot arm so as to control the wafer grabbing robot arm to grab the wafer according to the positioned coordinates. Figure 1 As shown, the processor can communicate with the wafer grabbing robot arm through a communication line to ensure the immediacy and accuracy of the communication.

[0070] In a feasible implementation scheme, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0071] Specifically, the negative pressure system can generate negative pressure on the wafer placed on the wafer carrying disc through the negative pressure hole, so that the wafer is adsorbed onto the wafer carrying disc. When the wafer carrying disc is rotated, the wafer moves or even falls. The negative pressure system can provide a negative pressure of more than 0.6Mpa. The negative pressure system can generate negative pressure only when there are wafers on the wafer carrying disc, or it can generate negative pressure in real time. The specific negative pressure size and working mode provided by the negative pressure system can be set according to actual needs and are not specifically limited here.

[0072] In a feasible implementation manner, the processor is a programmable logic controller, wherein the programmable logic controller may specifically be a Siemens 1200 series.

[0073] Figure 2 A schematic diagram of a flow chart of a wafer positioning method used in a semiconductor manufacturing process provided in an embodiment of the present application. The positioning method is applied to Figure 1 The positioning system shown in the figure, the positioning method runs in a processor, such as Figure 2 As shown, the positioning method includes the following steps:

[0074] Step 201, after the wafer grabbing robot places the wafer on the wafer carrying disc, obtain the first distance d1 to the edge of the wafer measured by the first photoelectric sensor, the second distance d2 to the edge of the wafer measured by the second photoelectric sensor, and the third distance d3 to the edge of the wafer measured by the third photoelectric sensor.

[0075] Step 202, determining, based on the first distance d1, a first coordinate (X1-d1, 0) of a first edge point of the wafer on the side of the wafer close to the first photoelectric sensor when the wafer is in the initial state of the wafer carrying disc, and determining, based on the second distance d2, a second coordinate (0, Y1-d2) of a second edge point of the wafer on the side of the wafer close to the second photoelectric sensor when the wafer is in the initial state of the wafer carrying disc, and determining, based on the third distance d3, a third coordinate (0, -(Y1-d3)) of a third edge point of the wafer on the side of the wafer close to the third photoelectric sensor when the wafer is in the initial state of the wafer carrying disc, which is located on the -Y axis of the two-dimensional coordinate system.

[0076] Step 203: Calculate the initial center coordinates of the wafer in the two-dimensional coordinate system according to the following formula 1: , ):

[0077] ;

[0078] ; (Formula 1)

[0079] Step 204: determine whether the wafer positioning notch is currently on the Y axis of the two-dimensional coordinate system according to the following target formula:

[0080] ;

[0081] in, is the rotation angle of the wafer supporting disc, when When the target formula is not equal, it is determined that the positioning notch of the wafer is currently located on the Y axis of the two-dimensional coordinate system.

[0082] Step 205: Calculate the rotation angle of the wafer supporting disk according to the following formula 2: When , the target center coordinates of the wafer in the two-dimensional coordinate system are:

[0083] ;

[0084] ; (Formula 2)

[0085] Step 206: Calculate the vector from the target circle center coordinates to the positioning gap according to the following formula 3:

[0086] ; (Formula 3)

[0087] Wherein, d4 is the rotation angle of the wafer supporting disc. When the third photoelectric sensor measures a fourth distance to the edge of the wafer.

[0088] Step 207: Determine the rotation angle of the wafer supporting disk according to the following formula 4: When The cosine angle between the Y axis and the two-dimensional coordinate system:

[0089] ; (Formula 4)

[0090] in, is the unit vector of the Y axis of the two-dimensional coordinate system.

[0091] Step 208: Control the wafer grabbing robot arm according to the positioning coordinates ( , , Z, a, b, ), positioning and grabbing the wafer;

[0092] Among them, the placement coordinates of the wafer grabbing robot arm are ( , , Z, a, b, ).

[0093] Specifically, Figure 2 As shown in the figure, after the wafer grabbing robot grabs the wafer, it needs to place the wafer on the wafer carrying disc. At this time, the placement coordinates of the wafer grabbing robot are ( , , Z, a, b, ), after the wafer is placed on the wafer carrier disc, the offset and rotation of the wafer relative to the standard position (i.e., the center of the wafer overlaps with the center of the wafer carrier disc, and the positioning notch of the wafer is located in the negative direction of the Y axis of the two-dimensional coordinate system) are unknown. At this time, the distance between the edge of the wafer and each photoelectric sensor when the wafer is in the initial state on the wafer carrier disc can be obtained through three photoelectric sensors. Since the distances of the three photoelectric sensors from the origin of the two-dimensional coordinate system are known, and the distances of each photoelectric sensor to the wafer corresponding to the three photoelectric sensors can also be obtained through the three photoelectric sensors. The distance from the edge of the wafer can be obtained, so the coordinates of the intersection of the edge of the wafer and the two-dimensional coordinate system when the wafer is in the initial state on the wafer supporting disc can be obtained. Then, the coordinates of the center of the wafer relative to the two-dimensional coordinate system when the wafer is in the initial state on the wafer supporting disc (that is, the initial center coordinates) can be determined respectively through formula 1. After the wafer is placed on the wafer supporting disc, the servo motor will rotate the wafer supporting disc. During the rotation process, the third distance d3 between the edge of the wafer and the negative direction of the Y-axis of the two-dimensional coordinate system and the rotation angle relative to the initial state at this time can be determined in real time. (i.e., the rotation angle of the wafer-carrying disc), and then the third distance d3 and the rotation angle , bring it into the target formula. When the positioning notch of the wafer is in the negative direction of the Y axis of the two-dimensional coordinate system, the third distance d3 determined is larger than other positions of the wafer, so that the target formula no longer holds. When the target formula no longer holds, it can be determined that the positioning notch of the wafer is in the negative direction of the Y axis of the two-dimensional coordinate system. Then the corresponding rotation angle at this time is Substituting into formula 2, we can determine the coordinates of the center of the wafer when the wafer positioning notch is in the negative direction of the Y axis of the two-dimensional coordinate system (i.e., the target center coordinates). After obtaining the target center coordinates, substitute the target center coordinates into formula 3 to determine the vector from the target center coordinates to the positioning notch when the wafer positioning notch is in the negative direction of the Y axis of the two-dimensional coordinate system. Then substitute the vector into formula 4 to determine the cosine angle. At this time, the target circle center coordinates represent the offset, and the cosine angle represents the rotation. Then, the placement coordinates of the wafer grabbing robot are adjusted according to the offset and rotation, and the adjusted coordinates are used as the grabbing coordinates to grab the wafer, so that after the wafer grabbing robot grabs the wafer according to the adjusted grabbing coordinates, the wafer can be placed on the next process to eliminate the offset and rotation of the wafer, thereby improving the yield of the semiconductor.

[0094] in, , cosine angle For vector The angle between the Y axis and the two-dimensional coordinate system can be transformed into the following result:

[0095]

[0096] In getting After the value of The specific value of .

[0097] Based on the above-mentioned positioning system, the present application also provides a corresponding positioning method. After obtaining the corresponding data through the above-mentioned positioning system, the processor uses the obtained data to position the wafer, so that the wafer grasping robot arm grasps the wafer through the new positioning data, so that the wafer grasping robot arm can eliminate the offset and rotation of the wafer when placing the wafer on the next process, thereby improving the semiconductor yield.

[0098] In a feasible implementation scheme, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0099] In a feasible embodiment, the processor is in communication with the negative pressure system, and the method further comprises:

[0100] After the wafer grabbing robot arm places the wafer on the wafer carrying disc, controlling the negative pressure system to generate negative pressure;

[0101] When the wafer grabbing robot arm grabs the wafer on the wafer carrying disc, the negative pressure system is controlled to turn off the negative pressure.

[0102] In one possible embodiment, the processor is a programmable logic controller.

[0103] Figure 3 A schematic diagram of a wafer positioning device used in a semiconductor manufacturing process provided in an embodiment of the present application, wherein the positioning device is used in Figure 1 In the processor of the positioning system, Figure 3 As shown, the positioning device comprises:

[0104] an acquisition unit 31, configured to acquire, after the wafer grabbing robot arm places the wafer on the wafer carrying disc, a first distance d1 to the edge of the wafer measured by the first photoelectric sensor, a second distance d2 to the edge of the wafer measured by the second photoelectric sensor, and a third distance d3 to the edge of the wafer measured by the third photoelectric sensor;

[0105] The determining unit 32 is used to determine, according to the first distance d1, a first coordinate (X1-d1, 0) of a first edge point of the wafer on the side of the wafer close to the first photoelectric sensor and located on the X-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and to determine, according to the second distance d2, a second coordinate (0, Y1-d2) of a second edge point of the wafer on the side of the wafer close to the second photoelectric sensor and located on the Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and to determine, according to the third distance d3, a third coordinate (0, -(Y1-d3)) of a third edge point of the wafer on the side of the wafer close to the third photoelectric sensor and located on the -Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc;

[0106] The first calculation unit 33 is used to calculate the initial center coordinates of the wafer in the two-dimensional coordinate system according to the following formula: , ):

[0107] ;

[0108] ;

[0109] The judgment unit 34 determines whether the positioning notch of the wafer is currently on the Y axis of the two-dimensional coordinate system according to the following target formula:

[0110] ;

[0111] in, is the rotation angle of the wafer supporting disc, when When the target formula is not equal, determining that the positioning notch of the wafer is currently located on the Y axis of the two-dimensional coordinate system;

[0112] The second calculation unit 35 is used to calculate the rotation angle of the wafer supporting disc according to the following formula: When , the target center coordinates of the wafer in the two-dimensional coordinate system are:

[0113] ;

[0114] ;

[0115] The third calculation unit 36 ​​is used to calculate the vector from the target circle center coordinate to the positioning gap according to the following formula:

[0116] ;

[0117] Wherein, d4 is the rotation angle of the wafer supporting disc. , a fourth distance to the edge of the wafer measured by the third photoelectric sensor;

[0118] The fourth calculation unit 37 is used to determine the rotation angle of the wafer supporting disc according to the following formula: When The cosine angle between the Y axis and the two-dimensional coordinate system:

[0119] ;

[0120] in, is the unit vector of the Y axis of the two-dimensional coordinate system;

[0121] The first control unit 38 is used to control the wafer grabbing robot arm to position the wafer according to the positioning coordinates ( , , Z, a, b, ), positioning and grabbing the wafer;

[0122] Among them, the placement coordinates of the wafer grabbing robot arm are ( , , Z, a, b, ).

[0123] In a feasible implementation scheme, a plurality of negative pressure holes are provided on the wafer carrying disc, and the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

[0124] In a feasible embodiment, the processor is in communication with the negative pressure system, and the device further comprises:

[0125] The second control unit is used to control the negative pressure system to generate negative pressure after the wafer grasping robot arm places the wafer on the wafer carrying disc; and to control the negative pressure system to turn off the negative pressure when the wafer grasping robot arm grasps the wafer on the wafer carrying disc.

[0126] about Figure 3 Related principles can be found in Figure 1 and Figure 2 The relevant explanations in the text will not be explained in detail here.

[0127] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0128] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0129] In addition, each functional unit in the embodiments provided in the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0130] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

[0131] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and are not to be understood as indicating or implying relative importance.

[0132] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-mentioned embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. They should all be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for positioning a wafer in a semiconductor manufacturing process, characterized in that: The positioning method is applied to a positioning system, the positioning system includes a positioning device and a wafer grabbing robot arm, the positioning device includes: a first photoelectric sensor, a second photoelectric sensor, a third photoelectric sensor, a wafer carrying disc, a servo motor and a processor, the servo motor is used to drive the wafer carrying disc to rotate, the position line of the second photoelectric sensor and the third photoelectric sensor is perpendicular to the X-axis in the three-axis coordinate system corresponding to the wafer grabbing robot arm, the third photoelectric sensor is located on the side close to the wafer grabbing robot arm, the first photoelectric sensor is located on the center line of the second photoelectric sensor and the third photoelectric sensor, in a two-dimensional coordinate system constructed with the center line as the X-axis and the midpoint of the second photoelectric sensor and the third photoelectric sensor as the origin, the coordinates of the first photoelectric sensor are (X1, 0), the coordinates of the second photoelectric sensor are (0, Y1), and the coordinates of the third photoelectric sensor are (0, -Y1), the values ​​corresponding to X1, Y1 and -Y1 are equal and greater than the radius R of the wafer, the origin of the two-dimensional coordinate system overlaps with the center of the wafer carrying disc, and the first photoelectric sensor, the second photoelectric sensor and the third photoelectric sensor are located on the center line of the three-axis coordinate system corresponding to the wafer grabbing robot arm. The height of the electric sensor and the third photoelectric sensor is the same as the height of the wafer placed on the wafer carrying disc. The wafer grabbing robot arm is used to place the wafer transferred from the upstream process transport rail on the wafer carrying disc, and to grab the wafer on the wafer carrying disc to the downstream process transport rail after positioning is completed. The processor is respectively connected to the first photoelectric sensor, the second photoelectric sensor, the third photoelectric sensor, the servo motor and the wafer grabbing robot arm for communication. The first photoelectric sensor is used to measure the distance between the edge point of the wafer on the X-axis of the two-dimensional coordinate system on the side close to the first photoelectric sensor and the first photoelectric sensor. The second photoelectric sensor is used to measure the distance between the edge point of the wafer on the Y-axis of the two-dimensional coordinate system on the side close to the second photoelectric sensor and the second photoelectric sensor. The third photoelectric sensor is used to measure the distance between the edge point of the wafer on the Y-axis of the two-dimensional coordinate system on the side close to the third photoelectric sensor and the third photoelectric sensor. The positioning method runs in the processor, and the positioning method includes: After the wafer grabbing robot arm places the wafer on the wafer carrying disc, obtaining a first distance d1 to the edge of the wafer measured by the first photoelectric sensor, a second distance d2 to the edge of the wafer measured by the second photoelectric sensor, and a third distance d3 to the edge of the wafer measured by the third photoelectric sensor; Determine, according to the first distance d1, a first coordinate (X1-d1, 0) of a first edge point of the wafer on the side of the wafer close to the first photoelectric sensor and located on the X-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and determine, according to the second distance d2, a second coordinate (0, Y1-d2) of a second edge point of the wafer on the side of the wafer close to the second photoelectric sensor and located on the Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc, and determine, according to the third distance d3, a third coordinate (0, -(Y1-d3)) of a third edge point of the wafer on the side of the wafer close to the third photoelectric sensor and located on the -Y-axis of the two-dimensional coordinate system when the wafer is in the initial state of the wafer carrying disc; The initial center coordinates of the wafer in the two-dimensional coordinate system are calculated according to the following formula: , ): ； ； Determine whether the wafer positioning notch is currently on the Y axis of the two-dimensional coordinate system according to the following target formula: ； in, is the rotation angle of the wafer supporting disc, when When the target formula is not equal, determining that the positioning notch of the wafer is currently located on the Y axis of the two-dimensional coordinate system; According to the following formula, when the rotation angle of the wafer supporting disc is When , the target center coordinates of the wafer in the two-dimensional coordinate system are: ； ； The vector from the target circle center coordinate to the positioning gap is calculated according to the following formula: ； Wherein, d4 is the rotation angle of the wafer supporting disc. , a fourth distance to the edge of the wafer measured by the third photoelectric sensor; The rotation angle of the wafer supporting disc is determined according to the following formula: When The cosine angle between the Y axis and the two-dimensional coordinate system: ； in, is the unit vector of the Y axis of the two-dimensional coordinate system; Control the wafer grabbing robot arm according to the positioning coordinates ( , , Z, a, b, ), to position and grab the wafer, where: is the offset distance on the X-axis when the wafer grabbing robot arm grabs the wafer, is the offset distance on the Y axis when the wafer grabbing robot grabs the wafer, Z is the upper and lower distance of the wafer grabbing robot relative to the wafer carrying platform, a is the rotation angle of the wafer grabbing robot along the X axis in the three-axis coordinate system, b is the rotation angle of the wafer grabbing robot along the Y axis in the three-axis coordinate system, is the rotation angle of the C-axis of the wafer grabbing robot; Among them, the placement coordinates of the wafer grabbing robot arm are ( , , Z, a, b, ).

2. The positioning method according to claim 1, characterized in that: The wafer carrying disc is provided with a plurality of negative pressure holes, the negative pressure holes are connected to a negative pressure system, and the negative pressure system adsorbs the wafer placed on the wafer carrying disc through the negative pressure holes.

3. The positioning method according to claim 2, characterized in that: The processor is in communication with the negative pressure system, and the method further comprises: After the wafer grabbing robot arm places the wafer on the wafer carrying disc, controlling the negative pressure system to generate negative pressure; When the wafer grabbing robot arm grabs the wafer on the wafer carrying disc, the negative pressure system is controlled to turn off the negative pressure.

4. The positioning method according to claim 1, characterized in that: The processor is a programmable logic controller.

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