TWI426575B - Wafer positioning system and method thereof - Google Patents

Description

Wafer positioning system and method thereof

The present invention relates to a wafer positioning system and method thereof, and more particularly to a system for sensing wafer position in a transfer chamber and a method therefor.

Film forming machines currently used in the industry, such as Physical Vapor Deposition (PVD) instruments and Plasma Enhanced Chemical Vapor Deposition (PECVD) instruments, through group cavities ( The Cluster Chamber) is widely used in mass production film forming equipment because of its flexibility and flexibility in mass production and mass production. Among them, the mass production type film forming equipment must use a robot arm, which is responsible for transferring the wafer to the cavity of each film forming machine to complete several different film forming processes. However, whether the wafer can be accurately placed in the cavity in the film forming process will affect the yield of the film forming process. Therefore, how to instantly monitor the actual position of the wafer in the cavity, that is, to instantly detect the placement of the wafer on the robot arm, is a very important key technology.

At present, there are several patents on wafer position detection technology, most of which use several photo detectors, combined with the occlusion method, to cover the time difference of the photodetector being covered by the wafer. To determine if there is a deviation in the wafer position. Applied Materials, Inc. introduced a patent for wafer positioning systems using photodetectors in 1998 and 1999, respectively, for robotic arm transporting wafers from the transport cavity into and out of the wafer storage tank. (cassette) and processing chamber. In addition, there are also a number of wafer positioning related patents that use a charge coupled device (CCD) camera to capture wafer edge contour images, with appropriate planar backlights, using image processing techniques to calculate whether the wafer center position is mistaken.

Therefore, how to detect whether the wafer is accurately placed in the correct position in the cavity of the film forming machine to improve the yield of the process is a problem to be solved in the technical field.

It is an object of the present invention to provide a wafer positioning system and method thereof for detecting the position of a wafer to improve the yield of the process.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

A wafer positioning system according to a first embodiment of the present invention is adapted to sense a position of a wafer, including a light source module, a scattering surface, or the like. A photosensitive unit and a shipping unit.

The light source module emits a fan-shaped beam of light, wherein the light source module comprises a light source and a cylindrical lens, the light source emits a light beam, the cylindrical lens is disposed on the light path of the light beam, and the light beam is expanded by the lenticular lens The fan-shaped beam is formed. The scattering surface is disposed on the light path of the fan-shaped beam expanding light, and is configured to divide the fan-shaped beam expanding light into a first linear beam expanding light and a second linear beam expanding light, so that the first linear beam expanding light Traveling generally along a first optical path, the second linear beam expanding light travels generally along a second optical path. The photosensitive unit is disposed on the scattering surface and includes an arithmetic unit. The consignment unit is used for supporting the wafer and moving between the photosensitive unit and the scattering surface. The consignment unit has a reference point and two end points, the two ends are located on a horizontal line, and the reference point is located on one of the horizontal lines. And when the wafer is placed on the shipping unit, one of the centers of the wafer is substantially at the reference point.

When the wafer and the transport unit pass through the first light path and the second light path, the two end points respectively intersect the first linear beam expanding light to generate two first intersection points, the edge of the wafer and the second line expansion The beam rays meet, and two second intersection points are generated, the photosensitive unit captures two first intersection points and two second intersection points, and the operation unit calculates the center of the circle and the reference point according to the two first intersection points and the two second intersection points. An error value between.

In an embodiment, when the wafer and the transport unit pass through the first light path and the second light path, the first linear expanded beam and the second linear expanded light have a first spacing between the reference point and the reference point There is a second spacing between the horizontal lines where the two ends are located, and the first spacing is smaller than the second spacing.

In one embodiment, the reference point of the shipping unit and the arrangement of the two end points form a V-shaped opening, and the shipping unit includes a recess for placing the wafer.

A wafer positioning system according to a second embodiment of the present invention is adapted to sense a position of a wafer, including a light source module and a diffuse reflection surface, in order to achieve one or a part or all of the above or other purposes. , a photosensitive unit and a shipping unit.

The light source module emits a first fan-shaped beam and a second fan-shaped beam. The diffuse reflection surface is disposed on the light path of the first fan-shaped beam and the light path of the second fan-shaped beam to diffusely reflect the first fan-shaped beam and the second fan-shaped beam, respectively A first linear beam expanding ray is formed and travels generally along a first optical path, and a second linear beam expanding ray and travels generally along a second optical path. The photosensitive unit is disposed on the diffuse reflection surface and includes an arithmetic unit. The consignment unit is used for supporting the wafer and moving between the photosensitive unit and the diffuse reflection surface. The consignment unit has a reference point and two end points, the two ends are located on a horizontal line, and the reference point is located on one of the horizontal lines. And when the wafer is placed on the shipping unit, one of the centers of the wafer is substantially at the reference point.

In one embodiment, the light source module includes two light sources and a cylindrical lens. The two light sources respectively emit a first light beam and a second light beam. The cylindrical lens is disposed on the light path of the first light beam and the light path of the second light beam. The first beam and the second beam are respectively expanded by the lenticular lens to form a first fan-shaped beam and a second fan-shaped beam.

In one embodiment, the light source module includes a light source, a beam splitting unit, and a cylindrical lens. The light source emits a light beam, and the light beam is split by the splitting unit to form two light beams. After the two light beams are expanded by the lenticular lens, the first fan-shaped expanded light and the second fan-shaped expanded light are formed.

When the wafer and the transport unit pass through the first light path and the second light path, the two end points respectively intersect the first linear beam expanding light to generate two first intersection points, the edge of the wafer and the second line expansion The beam rays meet, and two second intersection points are generated, the photosensitive unit captures two first intersection points and two second intersection points, and the operation unit calculates the center of the circle and the reference point according to the two first intersection points and the two second intersection points. An error value between.

In order to achieve one or a part or all of the above or other purposes, a wafer positioning method according to a third embodiment of the present invention is suitable for sensing a position of a wafer, comprising: providing two linear beam-expanding rays; Providing a photosensitive unit on the two optical paths of the two linear beam expanding rays; providing a shipping unit to support the wafer and moving through the two optical paths, wherein the shipping unit has a reference point and two end points, and the two ends are located at one end On the horizontal line, the reference point is on a vertical line on one of the horizontal lines, and one of the centers of the wafer is substantially at the reference point; when the wafer and the transport unit pass through the two light paths, the ends are respectively separated from the linear expanded light At the first meeting, two first intersection points are generated, and the edge of the wafer and the other of the linear beam-expanding rays meet to generate two second intersection points; the photosensitive unit captures two first intersection points and two second intersection points Providing an arithmetic unit to convert the two first intersection points and the two second intersection points into four coordinates; and according to the four coordinates, the operation unit calculates an error value between the center of the circle and the reference point.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

Please refer to the first figure, which is a schematic diagram of a wafer positioning system 10 according to a first embodiment of the present invention. A wafer positioning system 10 is used in a transmission cavity of a film forming apparatus for sensing the position of a wafer W. The method includes: a light source module S including two light sources 100 and a cylindrical lens 200, a diffuse The reflecting surface 300, a photosensitive unit 400 and a shipping unit 500.

The light source module S is configured to emit a first fan-shaped expanded beam L1 and a second fan-shaped expanded beam L2, wherein the first fan-shaped expanded beam L1 and the second fan-shaped expanded beam L2 are transmitted through the two light sources 100. For example, a laser light source and a lenticular lens 200 are formed. The two light sources 100 respectively emit a first light beam and a second light beam. The lenticular lens 200 is disposed on the light path of the first light beam and the light path of the second light beam. The first light beam and the second light beam are respectively expanded by the lenticular lens 200. After the beam, the first fan-shaped expanded beam L1 and the second fan-shaped expanded beam L2 are formed. In one embodiment, the light source module S includes a light source 100, a beam splitting unit (not shown), and a lenticular lens 200. After the light source 100 emits a light beam, the light beam is split by the light splitting unit to form two light beams. After the two light beams are expanded by the lenticular lens 200, the first fan-shaped expanded light L1 and the second fan-shaped expanded light L2 are formed.

The diffuse reflection surface 300 is disposed on the light path of the first fan-shaped beam illuminating light L1 and the light path of the second fan-shaped beam illuminating light L2, and is located at the bottom of the transmission cavity, and has a roughened design and has a roughness surface. The first fan-shaped beam L1 and the second fan beam L2 are projected onto the diffuse reflection surface 300. The diffuse reflection surface 300 is used to diffusely reflect the first fan-shaped beam L1 and the second fan beam L2. And the rough surface of the diffuse reflection surface 300 can scatter the first fan-shaped expanded beam L1 and the second fan-shaped expanded beam L2, so that the curved line segment of the front end is elongated to form a first linear expansion beam a light L1' and a second linear beam expanding light L2', and the first linear beam expanding light L1' is scattered by the rough surface of the diffuse reflecting surface 300, and is scattered by all sides, and the first linear beam expanding light L1 is scattered in all directions. The middle part of the light travels along a first light path R1, and the second linear expanded light L2' is scattered by the rough surface of the diffuse reflection surface 300, and is scattered by the four sides, and the second linear beam ray L2 scattered in all directions A portion of the light travels along a second light path R2.

The photosensitive unit 400 is disposed on the diffuse reflection surface 300 and includes an arithmetic unit (not shown). The loading unit 500 is used to support the wafer W and is moved between the photosensitive unit 400 and the diffuse reflection surface 300. The loading unit 500, for example, a robot arm, includes a groove 510 for placing the wafer W. The erecting height of the lenticular lens 200 is lower than the moving level of the wafer W and the loading unit 500, so as to prevent the moving wafer W and the loading unit 500 from blocking the first linear beam expanding light L1' and the first The two-line expanded beam L2' cannot be incident on the diffuse reflection surface 300.

Please refer to the second figure, which is a schematic diagram of a wafer positioning system 20 according to a second embodiment of the present invention. A wafer positioning system 20 is used in a transmission cavity of a film forming apparatus for sensing the position of a wafer W. The method includes: a light source module S including a light source 100 and a cylindrical lens 200, a scattering surface 300a, a photosensitive unit 400 and a shipping unit 500.

The light source module S emits a fan-shaped expanded light L', wherein the fan-shaped expanded light L' is formed via a light source 100 such as a laser light source and a lenticular lens 200. The light source 100 emits a light beam L, the lenticular lens 200 is disposed on the light path of the light beam L, and the light beam L is expanded by the lenticular lens 200 to form a fan-shaped expanded light L'. The scattering surface 300a is disposed on the light path of the fan-shaped beam expanding light L' such that the fan-shaped beam expanding light L' is projected on the scattering surface 300a, and the scattering surface 300a further divides the fan-shaped beam expanding light L' into a first line. a beam expanding beam L1' and a second linear beam expanding beam L2', and the scattering surface 300a can scatter the first linear beam expanding beam L1' and the second linear beam expanding beam L2', so that the front end thereof The curved line segment is elongated, the first linear beam expanding light L1' travels along a first light path R1, and the second linear beam expanding light L2' travels along a second light path R2.

The photosensitive unit 400 is disposed on the scattering surface 300a and includes an arithmetic unit (not shown). The loading unit 500 is used to support the wafer W and move between the photosensitive unit 400 and the scattering surface 300a. The loading unit 500 includes a groove 510 for placing the wafer W. The erecting height of the lenticular lens 200 is lower than the moving level of the wafer W and the loading unit 500, so that the moving wafer W and the loading unit 500 block the fan-shaped expanding light L′ and cannot be incident to the lenticular lens 200. On the scattering surface 300a.

In the first and second figures, the fan-shaped beam expanding light L', the first fan-shaped beam expanding beam L1, and the second fan-shaped beam expanding beam L2 are used as sources of the linear beam-expanding light for scanning the wafer W, Therefore, the fan-shaped beam expanding light L', the first fan-shaped expanding beam L1, and the second fan-shaped expanding beam L2 must have a sufficiently long curved line segment R so that after being reflected by the scattering surface 300a or the diffuse reflecting surface 300 The length of the line segment of the first linear beam-expanding light L1' and the second linear beam-expanding light L2' formed can match the size of the wafer W, so that the photosensitive unit 400 can be captured first by the wafer W. The linear beam-expanding light L1' and the second linear beam-expanding light L2' are combined with reference to the third figure, which is an enlarged schematic view of the fan-shaped beam expanding light L' after the beam L is expanded by the lenticular lens 200. .

Since the space of the transmission cavity inside the film forming apparatus is limited, the light beam L emitted from the laser light source 100 can be formed into a sufficiently long curved line segment R by the lenticular lens 200 in a short distance space. The fan beam expands the light beam L', and further forms a first linear beam expanding light L1' having a sufficiently long line segment and a second linear beam expanding light L2'. As shown in Fig. 3A, the lenticular lens 200 has a flat surface 210 and a convex surface 220. After the light beam L emitted from the laser light source 100 enters the plane 210, it is emitted from the convex surface 220 to form a fan-shaped expanded light L'. Therefore, when designing the lenticular lens 200, it is necessary to consider the diameter of the laser light source 100, the radius of curvature of the convex surface 220 of the lenticular lens 200, and the refractive index thereof, which can be simulated by the ASAP simulation software, and the diameter of the light source. The relationship between the radius of curvature of the lenticular lens 200 and its refractive index is substituted into the YNU optical tracking algorithm to obtain the relationship between the length of the curved line segment R of the fan-shaped expanded beam L' and other parameters.

In order to generate a fan-shaped beam ray L' having a sufficiently long curved line R in a short distance space, the radius of curvature of the convex surface 220 of the lenticular lens 200 is preferably as small as possible, and the diameter of the laser light source 100 is small. The bigger the better. In the present embodiment, the material of the lenticular lens 200 is BK7, the refractive index is 1.51, and the radius of curvature of the convex surface 220 is 4.056 mm (mm), and the light source is a laser light source having a diameter of 3 mm (mm). As a result of the simulation, a fan-shaped flared light L' having a length of 126 mm (mm) of the curved line R can be produced on the scattering surface 300a or the diffuse reflection surface 300 at a distance of 300 mm. As for the size of the wafer W, 4 吋 wafer, if it is intended for a larger wafer, such as 8 吋 or 12 吋, the lenticular lens 200 and the light source 100 can be changed to obtain a fan with a curved line R longer. Shaped beam L'.

The loading unit 500 in the wafer positioning systems 10 and 20 has a reference point Q and two end points P. As shown in the fourth figure, the two ends P are located on a horizontal line M, and the reference point Q is located on the horizontal line M. On the vertical line N, and when a wafer (not shown) is placed in the recess 510 of the transport unit 500, one of the centers of the wafer is substantially at the reference point Q, and the reference point Q and both ends of the transport unit 500 The arrangement of points P forms a V-shaped opening 520. In the fourth figure, the broken lines V1 and V2 are extension lines inside the V-shaped opening 520, and the two extension lines V1 and V2 intersect with the reference point Q.

Referring to the fifth drawing, the wafer W is placed on the transport unit 500 in the first and second figures through the first linear expanded beam L1' and the second linear expanded beam L2'. When the wafer W and the transport unit 500 pass the first linear beam expanding light L1 ′ and the second linear beam expanding light L 2 ′, the wafer W and the loading unit 500 will shield the first linear beam expanding light L1 ′ and the first The two lines expand the partial line of the light beam L2, and the light and shadow changes, so that the two end points P respectively intersect the first linear beam expanding light L1', and two first intersection points A and B are generated, and the wafer W The edge intersects with the second linear beam expanding light L2' to generate two second intersection points C and D. The photosensitive unit 400 is, for example, a charge coupled device (CCD), and draws two first intersection points A and B. And two second intersection points C and D, and the arithmetic unit is based on the two first intersection points A and B and the two second intersection points C and D. Using the image processing technology, the CCD 400 filters unnecessary noise and scans the coordinates of the two first intersection points A and B and the two second intersection points C and D, and then calculates the center of the circle by using the geometric relationship operation. An error value between O and reference point Q. The first linear expanded beam L1' and the second linear expanded beam L2' have a first spacing d1, and the reference point Q has a second spacing d2 between the horizontal line M where the two ends P are located. A pitch d1 is smaller than the second pitch d2.

The following details how to calculate an error value between the center O and the reference point Q by using the coordinates of the first intersection points A and B and the second intersection points C and D, and the geometric relation operation. When the first linear beam expanding light L1' is blocked by the both ends P of the V-shaped opening 520, the first linear beam expanding light L1' is cut into three segments, and the two ends of the CCD 400 can be calculated. The coordinates of the first intersection point A of the inner edge of P and the coordinates of the first intersection point B, wherein the slope of the extension line V1 of the V-shaped opening 520 and the slope of the extension line V2 are known, and then the first intersection point A is The coordinates of the coordinates and the first intersection point B are substituted into the slope, and two straight point equations can be generated. After the cubic equation is solved, the coordinates of the reference point Q can be known. The second linear beam illuminating light L2 ′ is blocked by the wafer W, and the second linear beam expanding ray L2 ′ is cut into two segments, and the edge of the wafer W can be calculated through the operation unit of the CCD 400 . The coordinates of the first intersection point C of the two-line expanded beam L2' and the coordinates of the first intersection point D, wherein the radius of the wafer W is known, the coordinates of the center O of the wafer W can be obtained. By the coordinates of the reference point Q obtained above and the coordinates of the center O, the error value between the center O and the reference point Q can be calculated.

Referring to the first figure, the sixth figure is a wafer positioning method according to an embodiment of the present invention, and the steps thereof include the following steps: (S101): First, a two-pole laser light source is used as a light source, and two diode laser light sources are used. Two beams are emitted, and after the two beams penetrate a cylindrical lens, two fan-shaped beam expanding rays are generated, and two fan-shaped beam expanding rays are projected on the diffuse reflecting surface, and two fan-shaped expanding beams are generated on the diffuse reflecting surface. The light will be stretched by the curved line segment at the front end to form a two-line beam. The two linear beam expanding rays provided above travel along the two light paths, and a photosensitive unit is mounted on the light path to capture the light and shadow changes.

Step (S102): providing a shipping unit to support the wafer and moving through the two light paths. The shipping unit is fixed on the sliding rail, and a stepping motor is controlled by a controller to drive the sliding rail, so that the loading unit carries the wafer to move in the transmission cavity, and the shipping unit has a reference point and two end points, two The endpoint is on a horizontal line, the reference point is on a vertical line on one of the horizontal lines, and one of the centers of the wafer is substantially placed on the reference point. In addition, the erecting height of the lenticular lens in the step (S101) must be lower than the horizontal plane moved by the wafer and its shipping unit to prevent the moving wafer and its shipping unit from covering the linear expanded light to reach the diffuse reflection. On the surface.

Step (S103): when the wafer and the transport unit pass through the two light paths, the light and shadow of the linear beam-expanding light captured by the photosensitive unit may change, and the two ends respectively intersect with the linear beam-expanding light. The two first intersection points are generated, and the edge of the wafer intersects with another of the linear beam expanding rays to generate two second intersection points; the photosensitive unit captures two first intersection points and two second intersection points.

Step (S104): the photosensitive unit captures two first intersection points and two second intersection points, and the operation unit performs an image processing technique.

Step (S105): the arithmetic unit converts the two first intersection points and the two second intersection points into four coordinates, that is, an edge coordinate of the intersection of the two ends of the shipping unit and the linear beam expanding light, and an edge and a line The edge coordinates of another intersection of the beam.

Step (S106): According to the four coordinates, and using the geometric relation operation, the operation unit can calculate the error value between the center of the circle and the reference point.

The wafer positioning system and the method thereof according to the embodiments of the present invention are designed by the V-shaped opening of the shipping unit and the generation of the linear beam expanding light, and are shielded by the photosensitive unit and the wafer and the shipping unit. The light-shadow change of the linear expanded light is used for image processing to calculate the error value of the reference point of the shipping unit and the center of the wafer. The above system and method are used in the transmission cavity of the film forming apparatus, and the relative positional relationship between the reference point of the shipping unit and the center of the wafer can be known to adjust the position of the wafer placed in the transmission cavity, thereby improving the process Yield.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

10, 20. . . Wafer positioning system

100. . . light source

200. . . Cylindrical lens

210. . . flat

220. . . Convex

300. . . Diffuse surface

300a. . . Scattering surface

400. . . Photosensitive unit

500. . . Consignment unit

510. . . Groove

520. . . V-shaped opening

A, B, C, D. . . Meeting point

D1. . . First spacing

D2. . . Second spacing

L. . . beam

L’. . . Fan-shaped beam

L1. . . First fan-shaped beam

L2. . . Second fan-shaped beam

L1’. . . First linear beam

L2’. . . Second linear beam

M. . . Horizontal line

N. . . Vertical line

O. . . Center of mind

P. . . End point

Q. . . Reference point

R1. . . First light path

R2. . . Second light path

R. . . Curved line segment

S. . . Light source module

V1, V2. . . Extension cord

W. . . Wafer

The first figure is a schematic diagram of the wafer positioning system of the first embodiment.

The second figure is a schematic diagram of the wafer positioning system of the second embodiment.

The third figure is an enlarged schematic view showing that the light beam is expanded by the lenticular lens to form fan-shaped beam expanding light.

Figure 3A is a perspective view of a lenticular lens.

The fourth figure is a three-dimensional diagram of the shipping unit.

The fifth figure is a top view of the first and second figures when the wafer is placed on the shipping unit through the linear beam expanding light.

FIG. 6 is a flow chart of a wafer positioning method according to an embodiment of the present invention.

10. . . Wafer positioning system

100. . . light source

200. . . Cylindrical lens

300. . . Diffuse surface

400. . . Photosensitive unit

500. . . Consignment unit

510. . . Groove

L1. . . First fan-shaped beam

L2. . . Second fan-shaped beam

L1’. . . First linear beam

L2’. . . Second linear beam

R1. . . First light path

R2. . . Second light path

S. . . Light source module

W. . . Wafer

Claims (10)

A wafer positioning system, configured to sense a position of a wafer, comprising: a light source module that emits a fan-shaped beam of flared light; and a scattering surface disposed on the light path of the fan-shaped beam of flared light for Dividing the fan-shaped beam into a first linear beam and a second line beam, the first linear beam expanding along a first optical path, the second line expanding The light beam travels along a second light path; a light-sensing unit is disposed on the scattering surface and includes an arithmetic unit; and a transport unit for supporting the wafer, and the light-emitting unit and the scattering Moving between the faces, the shipping unit has a reference point and a two-end point on a horizontal line, the reference point is located on a vertical line of the horizontal line, and when the wafer is placed in the shipping unit In the upper case, a center of the wafer is substantially at the reference point, wherein when the wafer and the carrier unit pass the first optical path and the second optical path, the two ends are respectively associated with the first The linear beam of light meets and creates two first intersections. The edge of the wafer intersects with the second linear beam expanding light to generate two second intersection points, the photosensitive unit captures the two first intersection points and the two second intersection points, and the operation unit is based on the two A intersection point and the two second intersection points are calculated to calculate an error value between the center of the circle and the reference point. The wafer positioning system of claim 1, wherein the light source module comprises a light source and a cylindrical lens, the light source emits a light beam, the cylindrical lens is disposed on the light path of the light beam, and the light source The beam is expanded by the lenticular lens to form the fan-shaped beam. The wafer positioning system of claim 1, wherein the first linear expanded beam and the second when the wafer and the shipping unit pass the first optical path and the second optical path The linear flared light has a first spacing between the reference point and the horizontal line where the two end points are located, and the first spacing is smaller than the second spacing. The wafer positioning system of claim 1, wherein the reference point of the shipping unit and the arrangement of the two end points form a V-shaped opening, and the shipping unit includes a groove for placing Put the wafer. A wafer positioning system, configured to sense a position of a wafer, comprising: a light source module, emitting a first fan-shaped beam and a second fan-shaped beam; a diffuse reflection surface disposed at the a light path of the first fan-shaped beam and a light path of the second fan-shaped beam of light to diffusely reflect the first fan-shaped beam and the second fan-shaped beam to generate a a first linear beam expanding light and a second linear beam expanding light, wherein the first linear beam expanding light travels substantially along a first light path, and the second linear beam expanding light is substantially along a second a light-receiving path; a photosensitive unit disposed on the diffuse reflection surface and including an arithmetic unit; and a transport unit for supporting the wafer and moving between the photosensitive unit and the diffuse reflection surface, The shipping unit has a reference point and a two-end point on a horizontal line, the reference point is located on a vertical line of the horizontal line, and when the wafer is placed on the shipping unit, the crystal One of the centers of the circle is substantially at the reference point, wherein When the wafer and the transport unit pass through the first light path and the second light path, the two end points respectively intersect the first linear beam expanding light to generate two first intersection points, and the edge of the wafer is The second linear beam expands to form two second intersections, the photosensitive unit captures the two first intersections and the two second intersections, and the computing unit is based on the two first intersections and the Two second intersection points to calculate an error value between the center of the circle and the reference point. The wafer positioning system of claim 5, wherein the light source module comprises two light sources and a cylindrical lens, wherein the two light sources respectively emit a first light beam and a second light beam, wherein the lenticular lens is disposed on In the light path of the first light beam and the light path of the second light beam, the first light beam and the second light beam are respectively expanded by the lenticular lens to form the first fan-shaped expanded light and the second Fan-shaped beam of light. The wafer positioning system of claim 5, wherein the first linear beam and the second linear beam have a light when the wafer and the carrier pass through the two light paths The first spacing, the reference point and the horizontal line where the two end points are located, has a second spacing, the first spacing being less than the second spacing. The wafer positioning system of claim 5, wherein the reference point of the shipping unit and the arrangement of the two end points form a V-shaped opening, and the shipping unit includes a groove for placing The wafer. A wafer positioning method, configured to sense a position of a wafer, comprising: providing two linear beam-expanding rays; and providing a photosensitive unit on two optical paths of the two linear beam expanding rays; providing a shipping unit to support The wafer, and moving through the two light paths, wherein the shipping unit has a reference point and two end points, the two end points are located on a horizontal line, the reference point is located on one of the horizontal lines, and the crystal One of the center of the circle is substantially located at the reference point; when the wafer and the carrier unit pass the two light paths, the two end points respectively meet with the linear beam expanding light, and two first intersections are generated Pointing, the edge of the wafer intersects with another of the linear beam expanding rays to generate two second intersection points; the photosensitive unit captures the two first intersection points and the two second intersection points; providing an arithmetic unit Converting the two first intersection points and the two second intersection points into four coordinates; and according to the four coordinates, the operation unit calculates an error value between the center of the circle and the reference point. The wafer positioning method of claim 9, wherein the two-line beam expanding light has a first pitch when the wafer and the shipping unit pass the two light paths, the reference point and the two There is a second spacing between the horizontal lines where the endpoints are located, the first spacing being less than the second spacing.