TWI837967B - Wafer processing system and method of wafer localization - Google Patents

Abstract

A wafer processing system including a wafer transfer device, a wafer detect device and a processor is provided. The wafer transfer device moves a transparent wafer or an opaque wafer and outputs moving distances. The wafer detect device includes sensors. The sensor has a emitter, a receiver and an output circuit. The receiver receives a light from the emitter. The output circuit outputs an output voltage. When the receiver directly receives the light, the output voltage has a first voltage value greater than a threshold. When the opaque wafer is between the emitter and the receiver, the output voltage has a second voltage value. When the transparent wafer is between the emitter and the receiver, the output voltage has a third voltage value. The second voltage value and the third voltage value are smaller than the threshold. The processor localizes edge points of the transparent wafer or the opaque wafer according to the threshold, the moving distances and the output voltages of the sensors.

Description

Wafer processing system and method for positioning wafer

The present disclosure relates to a wafer processing system and a method for positioning a wafer, and more particularly to a wafer processing system and a method for positioning a wafer with a photo sensor.

With the rapid development of integrated circuit products, the demand for wafers, which are the raw materials of integrated circuits, is increasing day by day. In the production process of wafers, wafer positioning is basically necessary. Whether it is when transferring wafers or executing wafer processing, the deviation of wafers can easily cause errors in the machine. For operations that need to be performed on specific structures on the wafer, it is even more necessary to accurately grasp the relative position between operating tools such as optical microscope lenses or probes and the corresponding structures on the wafer.

The present disclosure provides a wafer processing system, which includes a wafer transport device, a wafer detection device and a processor. The wafer transport device moves a transparent wafer or an opaque wafer and outputs multiple moving distances. The wafer detection device includes multiple sensors, each of which includes a transmitting end, a receiving end and an output circuit. The receiving end receives light from the transmitting end. The output circuit is coupled to the receiving end and outputs a voltage. When the receiving end directly receives the light, the output voltage has a first voltage value greater than a threshold value. When the opaque wafer is between the transmitting end and the receiving end, the output voltage has a second voltage value. When the transparent wafer is between the transmitting end and the receiving end, the output voltage has a third voltage value, wherein the second voltage value and the third voltage value are less than the threshold value. The processor locates multiple edge points on a transparent or opaque wafer based on the threshold, travel distance, and output voltage of each of the sensors.

The present disclosure provides a method for positioning a wafer, comprising: adjusting an output voltage transmitted from each of a plurality of sensors to a processor; generating a judgment result according to the output voltage by the processor, wherein the output voltage is equal to a voltage threshold; when a transparent wafer is placed between a transmitting end and a receiving end of the sensor, outputting an output voltage having a first voltage value to the processor by the sensor; when the first voltage value is greater than the voltage threshold, adjusting a variable resistance of the sensor so that the output voltage has a second voltage value less than the voltage threshold; The transparent wafer is moved along a first direction through the sensors by a wafer transport device, and a plurality of moving distances are outputted; and a plurality of edge positions of the transparent wafer are generated by a processor according to the output voltage, voltage threshold and the moving distances of each of the sensors.

The present disclosure provides a method for positioning a wafer, the method comprising: measuring an output voltage of an output end of a sensor, when a receiving end of the sensor directly receives light from a transmitting end of the sensor, the output voltage has a first voltage value, when a first wafer is between the receiving end and the transmitting end, the output voltage has a second voltage value, and when a second wafer is between the receiving end and the transmitting end, the output voltage has a third voltage value; adjusting the sensor so that the first voltage value is greater than a voltage threshold value and the second voltage and the third voltage are less than the voltage threshold value; The first wafer or the second wafer is moved through the sensors by a wafer transport device, and a plurality of moving distances are outputted; and a plurality of edge positions of the first wafer or the second wafer is generated by a processor according to the output voltage, the voltage threshold and the moving distances of each of the sensors.

The following disclosure provides many different embodiments or examples for implementing different features of the provided subject matter. The following describes specific examples of components and arrangements to simplify one embodiment of the present invention. Of course, these are merely examples and are not intended to be limiting. For example, forming a first feature above or on a second feature in the following description may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features so that the first and second features may not be in direct contact. In addition, the present disclosure may repeat component symbols or letters in various examples. This repetition is for the purpose of simplicity and clarity and does not itself specify the relationship between the various embodiments or configurations discussed.

The terms used in this specification generally have their ordinary meaning in the art and in the specific context in which each term is used. The use of examples in this specification, including examples of any term discussed herein, is illustrative only and in no way limits the scope and meaning of an embodiment of the present invention or any exemplary term. Similarly, an embodiment of the present invention is not limited to the various embodiments given in this specification.

Further, for ease of description, spatially relative terms such as "below," "under," "below," "above," "above," and the like may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the accompanying figures. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein may be interpreted accordingly. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As used herein, "about", "approximately", or "substantially" shall generally refer to any approximation of a given value or range, which varies depending on the various fields involved, and its scope shall be consistent with the broadest interpretation understood by those skilled in the art to cover all such modifications and similar structures. In some embodiments, it shall generally refer to within 20 percent of a given value or range, preferably within 10 percent, and more preferably within 5 percent. The numerical values given herein are approximate, meaning that if not explicitly stated, the term "about", "approximately", or "substantially" can be inferred, or other approximate values are meant.

FIG. 1 is a block diagram of an example of a wafer processing system 100 according to some embodiments. The wafer processing system 100 includes a wafer processing device 110 and a wafer storage device 120. The wafer processing device 110 is used to move the wafers stored in the wafer storage device 120 and perform transfer position correction on the wafers. In different embodiments, the wafer storage device 120 can be a wafer cassette, a wafer box, or a wafer carrier, etc., for storing wafers.

In the example shown in FIG. 1 , the wafer processing device 110 includes a processor 111, a wafer detection device 112, a wafer transfer device 117, and a memory 118. The processor 111 is coupled to the wafer detection device 112, the wafer transfer device 117, and the memory 118. The wafer transfer device 117 is used to move the wafer from the wafer storage device 120 through the wafer detection device 112. The processor 111 is used to determine whether the wafer deviates from a predetermined position (for example, the center of a storage elevator for vertically moving the wafer inside the wafer processing device 110) through the wafer detection device 112 and calibrate it to the predetermined position through the wafer transfer device 117. In some embodiments, the wafer transfer device 117 is a robotic arm having a blade/fork for picking up wafers.

For illustration, the wafer detection device 112 includes a plurality of sensors 113, each of which includes a transmitting end 114, a receiving end 115, and an output circuit 116. The transmitting end 114 is a light source, such as a light-emitting diode. The receiving end 115 has a light-sensing element, such as a photoresistor. The receiving end 115 is used to generate a sensing voltage according to the intensity of the received light. The output circuit 116 is coupled to the receiving end 115. In some embodiments, the output circuit 116 is used as a voltage divider circuit and is used to generate an output voltage according to the sensing voltage of the receiving end 115. In some embodiments, the output circuit 116 is coupled to the processor 111 and is used to transmit an output voltage to the processor 111. The processor 111 is further used to determine whether there is a wafer between the transmitting end 114 and the receiving end 115 according to the received output voltage.

The embodiment shown in FIG. 1 is not intended to limit the present invention. In some embodiments, the processor 111 is not coupled to the receiving end 115 and the wafer detection device 112 further includes a processor different from the processor 111. The output circuit 116 is coupled to and transmits an output voltage to the processor of the wafer detection device 112. The processor of the wafer detection device 112 determines whether there is a wafer between the transmitting end 114 and the receiving end 115 based on the received output voltage and transmits the determination result to the processor 111.

Referring now to FIG. 2, FIG. 2 is a schematic diagram of a waferless sensor 113 between a transmitting end 114 and a receiving end 115 according to some embodiments. For ease of understanding, the same elements in FIG. 2 are represented by the same element symbols as in FIG. 1. For the sake of brevity, the specific operations of similar elements that have been discussed in detail in the above paragraphs are omitted herein unless the cooperative relationship with the elements shown in FIG. 2 is required.

As shown in FIG. 2 , the transmitting end 114 is disposed above the receiving end 115, and there is a space therebetween for a wafer to pass through. The transmitting end 114 is used as a light source to generate a light ray 201 that directly irradiates the receiving end 115. The receiving end 115 is used to generate a sensing voltage Vout1 according to the intensity of the received light ray 201. The output circuit 116 is coupled to the receiving end 115 and is used to generate an output voltage Vout2 at an output end 212 of the output circuit 116 according to the sensing voltage Vout1. In some embodiments, the output circuit 116 includes a variable resistor 211, and the ratio between the output voltage Vout2 and the sense voltage Vout1 can be changed by adjusting the resistance value of the variable resistor 211. For example, by increasing the resistance value of the variable resistor 211, the voltage value of the output voltage Vout2 generated according to the sense voltage Vout1 will increase accordingly.

Referring now to FIG. 3 , FIG. 3 is a schematic diagram of a sensor 113 having an opaque wafer 320 between the transmitting end 114 and the receiving end 115 according to some embodiments. For ease of understanding, the same reference numerals are used to represent the same elements in FIG. 3 as in FIG. 2 .

To illustrate, when the opaque wafer 320 (e.g., a silicon wafer) is at the sensing point P (the point where the light 201 generated by the transmitting end 114 is projected onto the wafer) between the transmitting end 114 and the receiving end 115, the opaque wafer 320 shields the light 201 from the transmitting end 114. In some embodiments, the output circuit 116 accordingly generates an output voltage Vout2 having a voltage value V1 close to 0 volts. In some embodiments, when the receiving end 115 directly receives the light 201, the output voltage Vout2 has a voltage value Vh, and the voltage value Vl is less than the voltage value Vh. In some embodiments, the voltage value Vl is approximately equal to 0.03 volts, and the voltage value Vh is approximately equal to 1.5 volts (the voltage values here are only examples and are not intended to limit the present case).

Referring now to FIG. 4 , FIG. 4 is a schematic diagram showing a sensor 113 with a transparent wafer 420 between the transmitting end 114 and the receiving end 115 according to some embodiments. For ease of understanding, the same reference numerals are used to represent the same elements in FIG. 4 , corresponding to FIG. 3 .

For illustration, when the transparent wafer 420 (e.g., a silicon carbide (SiC) wafer) is between the transmitting end 114 and the receiving end 115, the transmitting end 114 generates the light 201 which passes through the transparent wafer 420, and the light intensity received by the receiving end 115 is less than the light intensity when the light 201 is directly received. In some embodiments, as the receiving end 115 receives a lower light intensity, the receiving end 115 generates a lower sense voltage Vout1 and the output circuit 116 generates a lower output voltage Vout2 accordingly. According to some embodiments, the light intensity sensed by the receiving end 115 varies according to the position where the light 201 penetrates the transparent wafer 420, so the output circuit 116 accordingly generates an output voltage Vout2 belonging to a voltage value range (having a minimum voltage value Va and a maximum voltage value Vb). In some embodiments, the minimum voltage value Va is less than the voltage value Vh.

Referring now to FIG. 5 , FIG. 5 is a schematic diagram illustrating a wafer being moved through the wafer detection device 112 according to some embodiments. For ease of understanding, the same elements in FIG. 5 are represented by the same element symbols as in FIG. 4 and FIG. 3 .

For illustration, in the embodiment shown in FIG. 5 , the wafer transport device 117 (not shown in FIG. 5 ) moves the wafer (opaque wafer 320 or transparent wafer 420) along a moving direction 501 through a sensor 113 in the wafer detection device 112, and two edge points on the wafer (e.g., edge points a and a′ shown in FIG. 5 ) pass through the sensing point P. For example, as shown in FIG. 5 , when the wafer enters between the transmitting end 114 and the receiving end 115 along the moving direction 501, the light 201 is first projected on the edge point a. Then, the light 201 is sequentially projected on the points in the a-a′ section line as the wafer moves. When the wafer leaves between the emitting end 114 and the receiving end 115 along the moving direction 501, the light ray 201 is finally projected onto the edge point a′, and then the light ray 201 is directly projected onto the receiving end 115.

Now refer to FIG. 6 , which illustrates an exemplary relationship between the moving distance of the opaque wafer 320 and the voltage value of the output voltage Vout2 of the sensor 113 according to some embodiments, corresponding to FIG. 5 . For ease of understanding, the same element symbols are used to represent the same elements in FIG. 6 .

For illustration, the horizontal axis of FIG. 6 corresponds to the distance that the opaque wafer 320 moves from a starting point along the moving direction 501 along the wafer transport device 117. For example, in some embodiments, the wafer transport device 117 moves the opaque wafer 320 from the wafer storage device 120 to a fixed starting point, and then moves the opaque wafer 320 along the moving direction 501 through the wafer detection device 112, and at the same time, the wafer transport device 117 transmits the moving distance from the starting point to the processor 111. In some embodiments where the wafer transport device 117 is a robot arm, the wafer transport device 117 transmits the two-dimensional coordinates of the tray/fork of the robot arm relative to an origin (such as the starting point mentioned above) to the processor 111 every time it moves a fixed distance (in other words, one step), and then the processor 111 generates the moving distance based on the coordinates and the starting point.

In the example shown in FIG. 6 , the moving distance Da corresponds to the distance that the opaque wafer 320 moves when the edge point a of the opaque wafer 320 is between the transmitting end 114 and the receiving end 115 of the wafer detection device 112. Similarly, the moving distance Da' corresponds to the distance that the opaque wafer 320 moves when the edge point a' of the opaque wafer 320 is between the transmitting end 114 and the receiving end 115 of the wafer detection device 112.

In addition, the vertical axis shown in FIG. 6 corresponds to the voltage value of the output voltage Vout2 of the output circuit 116 in the sensor 113. According to the embodiment shown in FIG. 6, when the moving distance of the opaque wafer 320 is less than the moving distance Da or greater than the moving distance Da', the output voltage Vout2 has a voltage value Vh. When the moving distance of the opaque wafer 320 is greater than the moving distance Da and less than the moving distance Da', the opaque wafer 320 passes through the sensor 113 and shields the light 201 from the transmitting end 114 to the receiving end 115, so the output voltage Vout2 has a voltage value Vl lower than the voltage value Vh.

Continuing from the above paragraph, in some embodiments, the processor 111 determines whether the wafer passes through the sensor 113 according to a voltage threshold value Vth greater than the voltage value Vl and less than the voltage value Vh. For example, when the output voltage Vout2 of a sensor 113 is greater than the voltage threshold value Vth, the processor 111 determines that there is no wafer between the transmitting end 114 and the receiving end 115 of the sensor 113. On the contrary, when the output voltage Vout2 of a sensor 113 is less than the voltage threshold value Vth, the processor 111 determines that there is a wafer between the transmitting end 114 and the receiving end 115 of the sensor 113.

Now refer to FIG. 7 , which illustrates an exemplary relationship between the moving distance of the transparent wafer 420 and the voltage value of the output voltage Vout2 of the sensor 113 according to some embodiments, corresponding to FIG. 5 . For ease of understanding, the same element symbols are used to represent the same elements in FIG. 7 .

For illustration, the horizontal axis of FIG. 7 corresponds to the distance that the transparent wafer 420 moves along the moving direction 501 from the above-mentioned starting point along the wafer transport device 117. The vertical axis shown in FIG. 7 corresponds to the voltage value of the output voltage Vout2 of the output circuit 116 in the sensor 113. In FIG. 7, the moving distance Da corresponds to the distance that the transparent wafer 420 moves when the edge point a of the transparent wafer 420 is between the transmitting end 114 and the receiving end 115 of the wafer detection device 112. Similarly, the moving distance Da' corresponds to the distance that the transparent wafer 420 moves when the edge point a' of the transparent wafer 420 is between the transmitting end 114 and the receiving end 115 of the wafer detection device 112.

As shown in FIG. 7 , when the moving distance of the transparent wafer 420 is less than the moving distance Da or greater than the moving distance Da’, the output voltage Vout2 has a voltage value Vh. When the moving distance of the transparent wafer 420 is greater than the moving distance Da and less than the moving distance Da’, the output voltage Vout2 changes with the different positions of the transparent wafer 420 passing through the sensor 113 (in other words, the different penetration positions of the light 201 on the transparent wafer 420), and the voltage value of the output voltage Vout2 varies within a voltage value range from a voltage value Va to a voltage value Vb.

In the example shown in FIG. 7 , the minimum value Va of the voltage value range described in the previous paragraph is greater than the voltage threshold value Vth. Therefore, when the processor 111 determines whether there is a wafer between the transmitting end 114 and the receiving end 115 of the sensor 113 based on the voltage threshold value Vth, an error occurs. For example, when the transparent wafer 420 moves through the sensor 113, the output voltage Vout2 is between the voltage value Va and the voltage value Vb. The processor 111 determines that there is no wafer between the transmitting end 114 and the receiving end 115 of the sensor 113 based on the output voltage Vout2 being greater than the voltage threshold value Vth, but in fact, there is a transparent wafer 420 between the transmitting end 114 and the receiving end 115. In some embodiments, the output circuit 116 is adjusted so that when the wafer passes through the sensor 113, the voltage value of the output voltage Vout2 is less than the voltage threshold Vth (which will be described in detail below with reference to FIG. 8 ).

Referring now to FIG. 8 , FIG. 8 illustrates an exemplary relationship between the moving distance of the opaque wafer 320/transparent wafer 420 and the voltage value of the adjusted output voltage Vout2 of the sensor 113 according to some embodiments. For ease of understanding, the same elements in FIG. 8 are represented by the same element symbols as in FIG. 6 and FIG. 7 .

In some embodiments, the resistance value of the variable resistor 211 of the output circuit 116 is adjusted so that when a wafer is between the transmitting end 114 and the receiving end 115, the voltage value of the output voltage Vout2 is less than the voltage threshold Vth; when no wafer is between the transmitting end 114 and the receiving end 115, the voltage value of the output voltage Vout2 is greater than the voltage threshold Vth. Therefore, the processor 111 can correctly determine whether a wafer passes through the sensor 113 according to the voltage threshold Vth.

For example, in an embodiment in which the variable resistor 211 of the output circuit 116 is not adjusted, when there is no wafer between the transmitting end 114 and the receiving end 115, the output voltage Vout2 has a voltage value Vh; when the opaque wafer 320 moves between the transmitting end 114 and the receiving end 115 (the moving distance is greater than the moving distance Da and less than the moving distance Da’), the output voltage Vout2 has a voltage value Vl; conversely, when the transparent wafer 420 moves between the transmitting end 114 and the receiving end 115, the output voltage Vout2 has a voltage value within the range of voltage value Va to voltage value Vb. Since the voltage value Va is greater than the voltage threshold value Vth, the processor 111 cannot correctly determine whether a wafer passes through the sensor 113 based on the voltage threshold value Vth.

In contrast, in an embodiment in which the variable resistor 211 of the output circuit 116 is adjusted, when there is no wafer between the transmitting end 114 and the receiving end 115, the output voltage Vout2 has a voltage value Vh'; when the opaque wafer 320 moves between the transmitting end 114 and the receiving end 115 (the moving distance is greater than the moving distance Da and less than the moving distance Da'), the output voltage Vout2 has a voltage value Vl'; when the transparent wafer 420 moves between the transmitting end 114 and the receiving end 115, the output voltage Vout2 has a voltage value within the range of the voltage value Va' to the voltage value Vb', wherein the maximum voltage value Vb' is less than the voltage threshold value Vth and the voltage value Vh' is greater than the voltage threshold Vth, so the processor 111 can correctly determine whether a wafer passes through the sensor 113 based on the voltage threshold Vth.

Referring now to FIG. 9A , FIG. 9A illustrates an exemplary relationship between the opaque wafer 320 / transparent wafer 420 and the wafer detection device 112 according to some embodiments. For ease of understanding, the same reference numerals are used to represent the same elements in FIG. 9A , corresponding to FIG. 5 .

For illustration, in the embodiment shown in FIG. 9A , the wafer detection device 112 has sensors 113a, 113b, and 113c configured according to the sensor 113. The sensors 113a-113b are configured identically to each other and are arranged aligned with each other along the direction y. The sensor 113b is arranged at the center point C of the wafer detection device 112, and the sensors 113a and 113c are arranged on both sides of the sensor 113b in the direction y. The sensors 113a and 113c are both separated from the sensor 113b by a distance S1 (a distance S1 from the center point C).

Continuing with the above embodiment, as shown in FIG. 9A , when the center point 920 of the wafer (here the wafer includes the opaque wafer 320 and the transparent wafer 420) is aligned with the starting point, in the direction x (equal to the moving direction 501) perpendicular to the direction y, the edge point 911 of the wafer and the sensing point P1 of the sensor 113b are separated by a distance D1, and the edge point 912 of the wafer and the sensing point P1 of the sensor 113b are separated by a distance D2. In other words, when the wafer moves a distance D1, the wafer overlaps with the sensor 113b, and the edge point 911 is between the transmitting end and the receiving end of the sensor 113b; when the wafer moves a distance D2, the edge point 912 is between the transmitting end and the receiving end of the sensor 113b (that is, the wafer will leave the sensor 113b).

Similarly, when the center point 920 of the wafer is aligned with the starting point SP, in the direction x perpendicular to the direction y: the edge point 913 of the wafer and the sensing point P2 of the sensor 113a are at a distance D3; the edge point 914 of the wafer and the sensing point P2 are at a distance D4; the edge point 915 of the wafer and the sensing point P3 of the sensor 113c are at a distance D5; and the edge point 916 of the wafer and the sensing point P2 are at a distance D6. In other words, when the wafer moves a distance D3, the wafer overlaps with the sensor 113a, and the edge point 913 is between the transmitting end and the receiving end of the sensor 113a; when the wafer moves a distance D4, the edge point 914 is between the transmitting end and the receiving end of the sensor 113a. When the wafer moves a distance D5, the wafer overlaps with the sensor 113c, and the edge point 915 is between the transmitting end and the receiving end of the sensor 113c; when the wafer moves a distance D6, the edge point 916 is between the transmitting end and the receiving end of the sensor 113c.

In some embodiments, the memory 118 is used to store a plurality of moving distances (or moving steps) output by the wafer transport device 117 and the determination results of whether there is a wafer between the transmitting end and the receiving end generated according to the output voltage values of the sensors 113a-113c at these moving distances. For example, when the voltage value of the output voltage Vout2 is greater than the voltage threshold Vth, the processor 111 generates a determination result that there is no wafer between the transmitting end and the receiving end; conversely, when the voltage value of the output voltage Vout2 is less than the voltage threshold Vth, the processor 111 generates a determination result that there is a wafer between the transmitting end and the receiving end. The processor 111 is used to locate (find the position relative to a fixed point such as the center point C) multiple edge points (such as edge points 911-916) according to these determination results.

For example, every time the wafer transport device 117 moves one step, the processor 111 generates a judgment result of whether there is a wafer between the transmitting end and the receiving end according to the output voltage of the sensor 113b, and stores the moving distance and the judgment result in the memory 118. Among these judgment results, when the judgment results of multiple consecutive moving steps are that there is a wafer between the transmitting end and the receiving end, the processor 111 uses the moving distance of the minimum moving step as the distance D1 to locate the edge point 911, and uses the moving distance of the maximum moving step as the distance D2 to locate the edge point 912.

Continuing with the above example, please refer to FIG. 9B, which shows an exemplary relationship between the opaque wafer 320/transparent wafer 420 and the wafer detection device 112 corresponding to FIG. 9A according to some embodiments. For ease of understanding, the same element symbols are used to represent the same elements in FIG. 9B corresponding to FIG. 9A.

Specifically, the xy coordinates of the center point C are (0,0). The processor 111 generates the coordinates of the edge point 911 as (-D1,0) based on the distance D1. The processor 111 generates the coordinates of the edge point 912 as (-D2,0) based on the distance D2. As described above, in some embodiments, the processor 111 is used to generate the position of the center 920 of the wafer in the moving direction 501 according to the moving distance of the minimum moving step number and the moving distance of the maximum moving step number (for example, the xy coordinates of the center 920 of the wafer are ((D1-D2)/2,0).

Referring now to FIG. 10 , FIG. 10 illustrates an exemplary relationship between the offset opaque wafer 320/transparent wafer 420 and the wafer detection device 112 according to some embodiments. For ease of understanding, the same reference numerals are used to represent the same elements in FIG. 10 as in FIG. 9A .

For illustration, in the embodiment shown in FIG. 10 , the wafer is offset from the starting point SP by a distance D7 along the direction y. In the direction x: the edge point 911′ of the wafer is at a distance D1′ from the sensing point P1 of the sensor 113b; the edge point 912′ of the wafer is at a distance D2′ from the sensing point P1; the edge point 913′ of the wafer is at a distance D3′ from the sensing point P2 of the sensor 113a; the edge point 914′ of the wafer is at a distance D4′ from the sensing point P2; the edge point 915′ of the wafer is at a distance D5′ from the sensing point P3 of the sensor 113c; and the edge point 916′ of the wafer is at a distance D6′ from the sensing point P2.

In some embodiments, the processor 111 is used to determine the offset distance D7 according to the distance D3', the distance D4', the radius R of the wafer, and the spacing S1. For example, half of the difference between the distance D4' and the distance D3' is the length L1. The length L1 and the radius R are used to determine the length L2 between the wafer center point 920 and the sensing point P2 in the direction y, and the offset distance D7 is determined by the difference between the spacing S1 and the length L2. In some embodiments, the processor 111 determines the distance between edge point 913′ and edge point 914′ based on the difference between distance D4′ and distance D3′, and determines the distance between edge point 915′ and edge point 916′ based on the difference between distance D6′ and distance D5′, and then compares the distance between edge point 913′ and edge point 914′ and the distance between edge point 915′ and edge point 916′ to determine the offset direction of the wafer (for example, when the distance between edge point 913′ and edge point 914′ is larger, the processor 111 determines that the wafer is positively offset along direction y).

Referring now to FIG. 11 , FIG. 11 is a flowchart of a method 1100 for positioning a wafer according to some embodiments. At least some operations (or steps) in the method 1100 for positioning a wafer may be used to position a transparent wafer such as the transparent wafer 420 in FIG. 4 .

The method 1100 is merely an example and is not intended to limit the present invention. It should therefore be understood that more operations may be provided before, during, and after the method 1100 of FIG. 11 , and that some operations in the method 1100 may be replaced or removed. It is contemplated that the operations of the method 1100 may alternatively be performed in an order other than that shown in FIG. 11 . The manufacturing method 1100 includes operations 1101, 1102, 1103, 1104, 1105, and 1106, which will be discussed below.

In operation 1101, the output voltage Vout2 transmitted from each of the plurality of sensors 113 shown in FIG. 2 to the processor 111 is adjusted.

In some embodiments, the sensors are arranged along a direction y that is perpendicular to the direction x.

In operation 1102, the processor 111 generates a determination result based on the output voltage Vout2, and the output voltage Vout2 is equal to the voltage threshold Vth.

In operation 1103 , when the transparent wafer 420 is placed between the transmitting end 114 and the receiving end 115 of the sensor 113 , the sensor 113 outputs an output voltage Vout2 having a first voltage value to the processor 111 .

In operation 1104, when the first voltage value is greater than the voltage threshold value Vth, the variable resistor 211 of the sensor 113 is adjusted so that the output voltage Vout2 has a second voltage value less than the voltage threshold value Vth.

In operation 1105, the transparent wafer 420 is moved along the moving direction 501 through the sensors 113 by the wafer transport device 117, and a plurality of moving distances are output, such as the distances D1'-D6' in FIG. 10 .

In operation 1106, the processor 111 generates a plurality of edge positions of the transparent wafer 420 according to the output voltage Vout2 of each of the sensors 113, the voltage threshold Vth, and the movement distances.

In some embodiments, the method 1100 further includes generating a position of a center of the transparent wafer in a first direction according to a first edge position and a second edge position of the transparent wafer 420 passing through one of the sensors 113 .

Referring now to FIG. 12 , FIG. 12 is a flowchart of a method 1200 for positioning a wafer according to some embodiments. At least some operations (or steps) in the method 1200 for positioning a wafer may be used to position a wafer such as the opaque wafer 320 in FIG. 3 and the transparent wafer 420 in FIG. 4 .

The method 1200 is merely an example and is not intended to be limiting. It should therefore be understood that more operations may be provided before, during, and after the method 1200 of FIG. 12 , and that some operations in the method 1200 may be replaced or removed. It is contemplated that the operations of the method 1200 may alternatively be performed in an order other than that shown in FIG. 12 . The manufacturing method 1200 includes operations 1201, 1202, 1203, and 1204, which will be discussed below.

In operation 1201, the output voltage Vout2 of the output end of the sensor 113 as shown in Figure 2 is measured. When the receiving end 115 of the sensor 113 directly receives the light 201 from the transmitting end 114 of the sensor 113, the output voltage has a first voltage value (for example, Vh in Figure 6). When the first wafer (for example, the opaque wafer 320) is between the receiving end 115 and the transmitting end 114, the output voltage has a second voltage value (for example, Vl in Figure 6). When the second wafer (for example, the transparent wafer 420) is between the receiving end 115 and the transmitting end 114, the output voltage has a third voltage value (for example, Va in Figure 7).

In operation 1202, the sensor 113 is adjusted so that the first voltage value is greater than a voltage threshold value Vth, and the second voltage and the third voltage are less than the voltage threshold value Vth.

In some embodiments, the third voltage belongs to a voltage value range (e.g., voltage value Va' to voltage value Vb' in FIG. 8), and a maximum value of the voltage value range (e.g., Vb') is less than the voltage threshold Vth.

In operation 1203, the first wafer or the second wafer is moved through the sensor 113 by the wafer transfer device 117, and a plurality of moving distances (e.g., moving distances D1'-D6' in FIG. 10) are output.

In operation 1204, the processor 111 generates multiple edge positions of the first wafer or the second wafer (e.g., positions of edge points 911'-916' relative to the starting point SP) according to the output voltage Vout2, the voltage threshold Vth, and these moving distances.

In some embodiments, the method 1200 further generates, by the processor 111, an offset direction and an offset distance (such as the direction y and the offset distance D7 in FIG. 10 ) of the first wafer or the second wafer according to the edge positions.

In some embodiments, the first wafer or the second wafer is moved by the wafer transfer device 117 in the opposite direction to the offset direction by the offset distance.

In summary, the present disclosure provides a wafer processing system with a light sensor and a method for positioning a transparent wafer and an opaque wafer. The adjustable components in the sensor of the wafer detection device allow the wafer processing system to be adjusted for different types of wafers (with different light transmittances). Even when the type of wafer being operated is unknown, the adjusted wafer processing system can still detect whether a wafer passes through the wafer detection device through the sensor, and determine whether the wafer is offset and correct it to a predetermined position.

The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand the aspects of an embodiment of the present invention. Those skilled in the art should understand that an embodiment of the present invention can be easily used as a basis for designing or modifying other processes and structures in order to implement the same purpose and/or achieve the same advantages of the embodiment introduced in the present invention. Those skilled in the art should also recognize that such equivalent structures do not deviate from the spirit and scope of an embodiment of the present invention, and that various changes, substitutions and modifications can be performed in an embodiment of the present invention without departing from the spirit and scope of an embodiment of the present invention.

100:Wafer processing system

110: Wafer processing device

111:Processor

112: Wafer detection device

113:Sensor

114: Transmitter

115: Receiving end

116: Output circuit

117: Wafer transfer device

118: Memory

120: Wafer storage device

201: Light

211: Variable resistor

212: Output terminal

P: Sensing point

Vout1: Sense voltage

Vout2: output voltage

320: Opaque wafer

420: Transparent Wafer

501:Moving direction

a:Edge point

a’: edge point

Vh, Vl: voltage value

Vth: voltage threshold

Da, Da’: moving distance

Va, Vb: voltage value

Vh’, Vl’, Va’, Vb’: voltage value

113a, 113b, 113c: Sensor

911-916: Edge Point

920: Center point

C: Center point

D1-D6: Distance

P1, P2, P3: Sensing points

S1: Spacing

SP: Starting point

x: direction

y: direction

911’-916’: Edge Point

C: Center point

D1’-D6’: Distance

D7: Offset distance

L1, L2: Length

R: Radius

1100: Method for positioning wafer

1101-1106: Operation

1200: Method for positioning wafer

1201-1204: Operation

The aspects of one embodiment of the present invention will be best understood from the detailed description below when read in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of discussion. FIG. 1 is a block diagram of an example of a wafer processing system according to some embodiments; FIG. 2 is a schematic diagram of a sensor without a wafer between a transmitting end and a receiving end according to some embodiments; FIG. 3 is a schematic diagram of a sensor with an opaque wafer between a transmitting end and a receiving end according to some embodiments; FIG. 4 is a schematic diagram of a sensor with a transparent wafer between a transmitting end and a receiving end according to some embodiments; FIG. 5 is a schematic diagram of a moving wafer passing through a wafer detection device according to some embodiments; FIG. 6 is an exemplary relationship between a moving distance of an opaque wafer and a voltage value of an output voltage of a sensor according to some embodiments; FIG. 7 illustrates an exemplary relationship between the moving distance of a transparent wafer and the voltage value of the output voltage of a sensor according to some embodiments; FIG. 8 illustrates an exemplary relationship between the moving distance of an opaque wafer/transparent wafer and the voltage value of the adjusted output voltage of a sensor according to some embodiments; FIG. 9A illustrates an exemplary relationship between an opaque wafer/transparent wafer and a wafer detection device according to some embodiments; FIG. 9B illustrates an exemplary relationship between an opaque wafer/transparent wafer corresponding to FIG. 9A and a wafer detection device according to some embodiments; FIG. 10 illustrates an exemplary relationship between a shifted opaque wafer/transparent wafer and a wafer detection device according to some embodiments. FIG. 11 is a flowchart of a method 1100 for positioning a wafer according to some embodiments; and FIG. 12 is a flowchart of a method 1200 for positioning a wafer according to some embodiments.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

100: Wafer processing system

110: Wafer processing equipment

111: Processor

112: Wafer detection device

113:Sensor

114: Transmitter

115: receiving end

116: Output circuit

117: Wafer transfer device

118: Memory

120: Wafer storage device

Claims (10)

A wafer processing system includes: a wafer transport device for moving a transparent wafer or an opaque wafer and outputting a plurality of moving distances; a wafer detection device including a plurality of sensors, each of the sensors including: a transmitting end and a receiving end, wherein the receiving end is used to receive a light from the transmitting end; and an output circuit coupled to the receiving end and used to output an output voltage according to a sensed voltage of the receiving end, wherein when the receiving end directly receives the light, the output voltage has a first voltage value greater than a threshold value, wherein when the opaque wafer is between the transmitting end and the receiving end ... When the transparent wafer is between the transmitting end and the receiving end, the output voltage has a second voltage value, and when the transparent wafer is between the transmitting end and the receiving end, the output voltage has a third voltage value, wherein the output circuit is further used to adjust an output ratio between the sensed voltage and the output voltage so that the second voltage value and the third voltage value are less than the threshold value according to the comparison result of the second voltage value and the third voltage value with the threshold value; and a processor is used to locate a plurality of edge points on the transparent wafer or the opaque wafer according to the threshold value, the moving distances and the output voltage of each of the sensors. A wafer processing system as described in claim 1, wherein the output circuit further includes a variable resistor, and the output circuit is further used to generate the output voltage according to the sensed voltage and a resistance value of the variable resistor. A wafer processing system as described in any one of claims 1 to 2, wherein the wafer transport device moves the transparent wafer or the opaque wafer along a first direction to pass through the sensors, wherein the edge points are a first edge point and a second edge point of the transparent wafer or the opaque wafer passing through each of the sensors, wherein the first edge point and the second edge point of each of the sensors correspond to a first moving distance and a second moving distance output by the wafer transport device, wherein the processor is further used to generate a wafer center position of the transparent wafer or the opaque wafer in the first direction according to the first moving distance and the second moving distance. A wafer processing system as described in claim 3, wherein one of the sensors is arranged to align with a center of the wafer detection device in the first direction, and the one of the sensors is at a distance from the center in a second direction perpendicular to the first direction, wherein the processor is further used to generate an offset distance of the transparent wafer or the opaque wafer in the second direction according to the distance, a half diameter of the transparent wafer or the opaque wafer, and the first moving distance and the second moving distance corresponding to the one of the sensors. A wafer processing system as described in any one of claim 1 to 2, wherein the opaque wafer is a silicon wafer and the transparent wafer is a silicon carbide wafer. A method for positioning a wafer, comprising: adjusting an output voltage transmitted from each of a plurality of sensors to a processor; generating a judgment result according to the output voltage by the processor, wherein the output voltage is equal to a voltage threshold; when a transparent wafer is placed between a transmitting end and a receiving end of the sensor, the sensor outputs the output voltage having a first voltage value to the processor; when the first voltage value is greater than When the voltage threshold is reached, a variable resistor of the sensor is adjusted so that the output voltage has a second voltage value less than the voltage threshold; the transparent wafer is moved along a first direction through the sensors by a wafer transport device, and a plurality of moving distances are output; and a plurality of edge positions of the transparent wafer are generated by the processor according to the output voltage of each of the sensors, the voltage threshold and the moving distances. A method for positioning a wafer comprises: measuring an output voltage of an output circuit of a sensor, wherein when a receiving end of the sensor directly receives a light from a transmitting end of the sensor, the output voltage has a first voltage value, when a first wafer is between the receiving end and the transmitting end, the output voltage has a second voltage value, and when a second wafer is between the receiving end and the transmitting end, the output voltage has a third voltage value. voltage value; adjusting an output ratio of the output circuit so that the first voltage value is greater than a voltage threshold value and the second voltage and the third voltage are less than the voltage threshold value; moving the first wafer or the second wafer through the sensor through a wafer transport device and outputting a plurality of moving distances; and generating a plurality of edge positions of the first wafer or the second wafer according to the output voltage, the voltage threshold value and the moving distances through the processor. As described in claim 7, the first wafer is an opaque wafer and the second wafer is a transparent wafer. As described in claim 8, the third voltage belongs to a voltage value range, wherein a maximum value of the voltage value range is less than the voltage threshold value. The method described in any one of claims 7 to 9 further includes: generating an offset direction and an offset distance of the first wafer or the second wafer according to the edge positions by the processor; and moving the first wafer or the second wafer by the offset distance in the opposite direction to the offset direction by the wafer transport device.

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