TWI447843B - Wafer positioning method and system thereof - Google Patents

Description

Wafer positioning method and system thereof

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

The semiconductor film-forming equipment used in the industry is widely used in mass production film forming equipment by the design of a cluster chamber and its advantages of flexible process and mass production capability. . 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 one of the important keys affecting the process yield.

At present, the commonly used wafer position detection technology has been proposed in several patents. Most of them use several photo detectors and are equipped with an interrupting method. At the wafer storage and processing chambers of the body, the time difference of the photodetector being covered by the wafer is used to calculate whether there is a deviation in the wafer position. 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 method and system 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.

For one or a portion or all of the above or other purposes, a wafer positioning method according to an embodiment of the present invention is adapted to sense a position of a wafer, the step comprising: providing a shipping unit to support the wafer And the transport unit moves linearly at a moving speed; a laser scanning module is provided to emit a light beam, and the light beam is moved at a rotation angle to scan on the wafer and the transport unit, wherein the laser scanning mode The set and the transport unit have a fixed distance; a photosensitive module is provided to receive the light intensity of the light beam; and when the light beam meets the transport unit or the wafer, the photosensitive module captures one of the intensity of the light intensity of the light beam Changing; providing an arithmetic unit to record a change in intensity and a corresponding rotation angle of the light beam; the arithmetic unit calculates the position of the wafer according to the moving speed, the rotation angle, the time, and the fixed distance.

In one embodiment, the position of the wafer is represented by a plurality of wafer edge coordinates, and the arithmetic unit can calculate a center position of the wafer according to the edge coordinates of the wafer. Wherein, the edge coordinate of each wafer is represented by a horizontal coordinate and a vertical coordinate, and the horizontal coordinate is calculated according to the change of the fixed distance and the rotation angle, and the vertical coordinate is calculated by the change of the moving speed and time.

In one embodiment, the step of extracting the intensity of the photosensitive module comprises: when the beam is not intersected with the carrier unit and the wafer, the photosensitive module captures a first light intensity; when the edge of the shipping unit intersects with the beam The photosensitive module captures a second light intensity; when the edge of the wafer meets the beam, the photosensitive module captures a third light intensity. In addition, when the first light intensity is converted into the second light intensity, the operation unit records as a first time, and records the rotation angle of the light beam corresponding to the first time as a first rotation angle; when the first light intensity conversion For the third light intensity, the operation unit records a second time, and records the rotation angle of the light beam corresponding to the second time as a second rotation angle.

For one or a part or all of the above or other purposes, a wafer positioning system according to another embodiment of the present invention is adapted to sense a position of a wafer, including a shipping unit and a laser scanning The module, a photosensitive module and an arithmetic unit. The shipping unit is used to support the wafer and has a moving speed. The laser scanning module is disposed above the shipping unit and has a fixed distance from the shipping unit. The laser scanning module emits a beam of light that travels along a first optical path and the beam moves at a rotational angle for scanning on the wafer and the transport unit. The photosensitive module is configured to receive the light intensity of the light beam. When the light beam travels along the first light path and does not intersect the shipping unit and the wafer, the photosensitive module captures a first light intensity, and when the edge of the shipping unit meets the light beam The photosensitive module captures a second light intensity. When the edge of the wafer and the light beam, the photosensitive module captures a third light intensity. The computing unit is electrically connected to the photosensitive module and the laser scanning module to receive the first light intensity, the second light intensity, and the third light intensity.

Wherein, when the first light intensity is converted into the second light intensity, the operation unit records the first time, and records the rotation angle of the light beam corresponding to the first time as a first rotation angle. When the first light intensity is converted into the third light intensity, the operation unit records a second time, and records the rotation angle of the light beam corresponding to the second time as a second rotation angle. Finally, the arithmetic unit calculates the position of the wafer according to the moving speed, the first rotation angle, the second rotation angle, the first time, the second time, and the fixed distance.

In one embodiment, the laser scanning module includes a laser light source, a mirror, and a rotary brake unit. The laser source emits a beam of light and travels along a second path of light. A mirror is disposed on the second light path to reflect the beam and travel along the first light path. The rotating brake unit is electrically connected to the mirror, and the mirror is disposed on the rotating braking unit. The rotating braking unit rotates at a rotation angle and drives the mirror to rotate, so that the beam is scanned on the wafer and the loading unit at a rotation angle.

In one embodiment, the wafer positioning system further includes a scattering bottom surface disposed under the shipping unit. When the light beam travels along the first light path and does not intersect the shipping unit and the wafer, the light beam advances to the scattering bottom surface to generate A scattered light in which the intensity of the scattered light is the first light intensity.

In one embodiment, the position of the wafer is represented by a plurality of wafer edge coordinates, and the arithmetic unit can calculate a center position of the wafer according to the edge coordinates of the wafer. Wherein, the edge coordinate of each wafer is represented by a horizontal coordinate and a vertical coordinate, and the horizontal coordinate is calculated according to the change of the fixed distance and the rotation angle, and the vertical coordinate is calculated by the change of the moving speed and time.

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.

The wafer positioning method and system thereof are formed by using a laser scanning module to form a scanning beam by a laser scanning module, and receiving a scanning beam by a photosensitive module to travel to a consignment unit and one of the upper projections thereof The light intensity signal scattered by the wafer, and then the time interval of the light intensity change, to calculate the actual position of the wafer.

Please refer to the first figure, which is a flowchart of a wafer positioning method according to an embodiment of the present invention. A wafer positioning method is suitable for sensing the position of a wafer, and the steps are as follows:

Step (S10): providing a shipping unit to support the wafer, and the shipping unit moves linearly at a moving speed. At this time, a reference coordinate is defined, with the X-Y coordinate axis as a reference coordinate, and the Y-axis direction is defined as the direction in which the wafer moves forward, and the X-axis and the Y-axis are perpendicular to each other.

Step (S11): an arithmetic unit is provided, and the arithmetic unit records the moving speed V of the shipping unit.

Step (S12): providing a laser scanning module to emit a light beam, and the light beam is moved at a rotation angle to scan on the wafer and the shipping unit. Wherein, the laser scanning module and the shipping unit have a fixed distance h, and the scanning direction of the light beam in the laser scanning module is defined as the X-axis direction.

Step (S13): providing a photosensitive module to receive a light intensity scattered by the light beam on the wafer and the loading unit, and the photosensitive module extracts a change in intensity of the light intensity of the light beam.

Step (S14): The arithmetic unit records a time when the light intensity changes. When the beam does not meet the consignment unit and the wafer, the photosensitive module captures a first light intensity; when the edge of the consignment unit meets the beam, the photosensitive module captures a second light intensity; When the edge meets the beam, the photosensitive module captures a third light intensity. As a result, when the first light intensity is converted to the second light intensity, the arithmetic unit records the first time; when the first light intensity is converted to the third light intensity, the arithmetic unit records the second time.

Wherein, in the reference coordinate, the operation unit defines the position at which the transport unit is scanned by the beam for the first time as an origin, that is, the first time when the first light intensity first rises to the second light intensity. position.

Step (S15): At the same time, when the computing unit corresponds to the first time and the second time respectively, the rotation angle of the beam scanning to the wafer and the shipping unit is taken. When the first light intensity is converted into the second light intensity, the operation unit captures the rotation angle of the light beam corresponding to the first time, and records it as a first rotation angle; when the first light intensity is converted into the third light intensity The arithmetic unit captures the rotation angle of the beam corresponding to the second time and records it as a second rotation angle.

Step (S16): The arithmetic unit calculates the position of the wafer according to data such as the moving speed, the rotation angle, the first time, the second time, and the fixed distance. The position of the wafer may be represented by a plurality of wafer edge coordinates, and each wafer edge coordinate is represented by a horizontal coordinate and a vertical coordinate, that is, represented by the X-axis and the Y-axis in the reference coordinate. The horizontal coordinate X _{i is} also the X-axis coordinate, which is calculated based on the change of the fixed distance and the rotation angle. The vertical coordinate Y _{i is} also the Y-axis coordinate, which can be calculated from the change of the moving speed and time.

Therefore, the wafer edge coordinates P _i (X _i , Y _i ) can be calculated from the following relationship:

X _i = h [tan( θ _i )-tan( θ _o )]

Y _i = V [ t _i - t _o ]

The first time t _o and the first angle θ _o respectively indicate that the beam of the laser scanning module is scanned to the origin, that is, the first time when the first light intensity first rises to the second light intensity corresponds to The position, and the angle of rotation of the beam in the laser scanning module. The time t _i and the rotation angle θ _i of the light beam respectively indicate the position of the beam scanning to the edge of the wafer in the laser scanning module. As for, h represents the fixed distance of the laser scanning module and the shipping unit, and V represents the moving speed of the shipping unit.

Step (S17): According to the wafer edge coordinates P _i (X _i , Y _i ), the operation unit can calculate a center position (X _C , Y _C ) of the wafer, and the relationship is as follows:

The following is a schematic diagram of the structure of the wafer positioning system according to the embodiment of the present invention to explain the above wafer positioning method in detail. A wafer positioning system is suitable for use in a transmission cavity of a film forming apparatus for sensing a position of a wafer W, comprising a shipping unit 100, a main laser source 200, a mirror 210, and a rotating The laser scanning module 220 includes a laser scanning module, a photosensitive module 230 and an arithmetic unit 240. The transport unit 100 is configured to support the wafer W and linearly move in a transport cavity of the film forming apparatus at a moving speed V. The transport cavity has a scattering bottom surface P disposed below the transport unit 100.

The laser scanning module is disposed above the shipping unit 100, and the mirror 210 and the rotating braking unit 220 have a fixed distance h from the shipping unit 100. The laser source 200 emits a beam of light, and the mirror is disposed on the light path of the beam to reflect the beam and travel along the first path L. The rotating brake unit 220 is electrically connected to the mirror 210, and the mirror 210 is disposed on the rotating brake unit 200. Therefore, when the rotating braking unit 220 rotates at a rotation angle θ, the mirror 210 is rotated to rotate the beam. The angle θ is moved to reciprocate on the wafer W and the transport unit 100 to form a scanning ray. In an embodiment, the laser source 200 includes a laser source.

The photosensitive module 230 is configured to receive the light intensity of the light beam. During the continuous scanning of the light beam at the rotation angle in the laser scanning module, the light beam is repeatedly irradiated on the surface of the transport unit 100, the scattering bottom surface P of the transmission cavity and the wafer W, and the photosensitive module 230 respectively accepts To different intensity of scattered light. When the light beam travels along the first light path L and does not intersect the carrier unit 100 and the wafer W, the light beam proceeds to the scattering bottom surface P to generate a first scattered light, and the light intensity of the first scattered light is first. The light intensity, the photosensitive module 230 will capture a first light intensity. When the edge of the transport unit 100 intersects the light beam, a second scattered light is generated, and the light intensity of the second scattered light captured by the photosensitive module 230 is a second light intensity. When the edge of the wafer W intersects with the beam, a third scattered light is generated, and the light intensity of the third scattered light captured by the photosensitive module 230 is a third light intensity.

The computing unit 240 includes a control unit 241 and a capture component 242 such as a data acquisition card (DAQ card). The operation unit 240 is electrically connected to the rotary brake unit 220 in the laser scanning module by the control unit 241 and the capture unit 242. The control unit 241 can output a sine wave signal to drive the rotary brake unit 220, so that the rotary brake unit 220 is rotated. The mirror 210 is rotated to reciprocate, and the capturing element 242 transmits the rotation angle of the rotation of the rotating brake unit 220 to the arithmetic unit 240. At the same time, the computing unit 240 can receive the first light intensity, the second light intensity, and the third light intensity sensed by the photosensitive module 230 by capturing the component 242.

Referring to the third and fourth figures, the photosensitive module 230 uses the first light intensity I ₁ as a reference signal to plot the change of the scattered light intensity into a graph, as shown in the fourth figure, wherein the scattered light intensity is the vertical axis, and The time is the horizontal axis. As can be seen from the fourth graph, there is a significant sharp change between the second light intensity I ₂ and the third light intensity I ₃ . Using the moment of dramatic change in light intensity, it can be determined whether the beam is scanned to the edge of the loading unit 230 or the edge of the wafer W, and the time point at which the beam intersects with different objects is recorded, and the beam in the corresponding laser scanning module The angle of rotation. Therefore, when the first light intensity is converted into the second light intensity, that is, when the light beam is scanned from the scattering bottom surface P to the edge of the hauling unit 100, the operation unit 240 records the first time t _o , and corresponds to the first time The angle of rotation of the beam at a time t _o is recorded as a first angle of rotation θ _o and can be recorded as P _o (t _o , θ _o ). When the first light intensity is converted to the third light intensity, that is, when the light beam is scanned from the scattering bottom surface P to the edge of the wafer W, the arithmetic unit 240 records a second time t _i and corresponds to the second time t _i The angle of rotation of the beam is recorded as a second angle of rotation θ _i and this position can be recorded as P _i (t _i , θ _i ). Finally, in conjunction with the steps (S16) to (S17) of the wafer positioning method in the first figure, the operation unit 240 is based on the moving speed V of the shipping unit 100, the first rotation angle θ _o , the second rotation angle θ _i , and the first time. t _o , the second time t _i and the fixed distance h to calculate the position of the wafer W.

The wafer positioning method and system thereof according to the embodiments of the present invention form a scanning light by using a laser scanning module, and detect a timing change of the scattered light intensity by the photosensitive module to calculate the position of the wafer. Therefore, by calculating the position of the wafer, it is checked whether the wafer is accurately placed in the correct position in the cavity of the film forming machine, and the shipping unit will finely adjust the position according to the position of the wafer to reduce The position error of the wafer placed in the transfer cavity increases process yield and accuracy.

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.

W. . . Wafer

100. . . Consignment unit

200. . . Laser source

210. . . Reflector

220. . . Rotating brake unit

230. . . Photosensitive module

240. . . Arithmetic unit

241. . . control unit

242. . . Capture component

P. . . Scattering bottom

h. . . Fixed distance

L. . . Light path

V. . . Moving speed

I ₁ . . . First light intensity

I ₂ . . . Second light intensity

I ₃ . . . Third light intensity

t _o . . . first timing

t _i . . . Second time

θ. . . Rotation angle

θ _o . . . First rotation angle

θ _i . . . Second angle of rotation

P _o (t _o , θ _o ), P _i (t _i , θ _i ). . . Meeting location

The first figure is a flow chart of a wafer positioning method according to an embodiment of the present invention.

The second figure is an architectural diagram of a wafer positioning system according to an embodiment of the present invention.

The third figure is a schematic diagram of the shipping unit and the wafer placed thereon.

The fourth graph is a plot of the intensity of the scattered light versus time.

Claims (8)

A wafer positioning method for sensing a position of a wafer, comprising: providing a shipping unit to support the wafer, and the shipping unit moves linearly at a moving speed; providing a laser scanning module for transmitting a light beam, wherein the light beam is moved at a rotation angle, and is scanned on the wafer and the carrier unit, wherein the laser scanning module and the shipping unit have a fixed distance; and a photosensitive module is provided. Receiving a light intensity of the light beam; when the light beam intersects the shipping unit or the wafer, the photosensitive module captures a change in intensity of the light intensity of the light beam; providing an arithmetic unit to record the a time at which the intensity changes, and the corresponding rotation angle of the light beam; and the operation unit calculates the position of the wafer according to the moving speed, the rotation angle, the time, and the fixed distance; wherein the wafer The position is represented by a plurality of wafer edge coordinates, and each of the wafer edge coordinates is represented by a horizontal coordinate and a vertical coordinate, and the horizontal coordinate is based on the fixed distance and the rotation The resulting change in the angle calculated, the coordinate system computed by the vertical and the change in the moving velocity of the time available and, in accordance with the plurality of wafer edge coordinates, the arithmetic unit may calculate to obtain the center position of one wafer. The wafer positioning method according to claim 1, wherein the photosensitive module captures the intensity change step, comprising: when the light beam is not intersected with the shipping unit and the wafer, the photosensitive module A first light intensity is captured; when the edge of the shipping unit intersects the beam, the photosensitive module captures a second light intensity; and when the edge of the wafer meets the beam, the photosensitive mode The group will draw a third light intensity. The wafer positioning method of claim 2, wherein the calculating unit records the time of the intensity change and the corresponding rotation angle, comprising: converting the first light intensity to the second light intensity The operation unit records a first time, and records the rotation angle of the light beam corresponding to the first time as a first rotation angle; and when the first light intensity is converted into the third light intensity, The operation unit records a second time, and records the rotation angle of the light beam corresponding to the second time as a second rotation angle. A wafer positioning system, configured to sense a position of a wafer, comprising: a shipping unit for supporting the wafer and having a moving speed; and a laser scanning module disposed on the shipping unit Above, and at a fixed distance from the shipping unit, the laser scanning module emits a light beam that travels along a first optical path and the light beam moves at a rotation angle on the wafer and the consignment The unit is configured to receive a light intensity of the light beam. When the light beam travels along the first light path and does not intersect the loading unit and the wafer, the photosensitive module captures one First light intensity when the edge of the shipping unit intersects the beam In time, the photosensitive module captures a second light intensity. When the edge of the wafer and the light beam, the photosensitive module captures a third light intensity; and an arithmetic unit electrically connects the photosensitive module And the laser scanning module to receive the first light intensity, the second light intensity, and the third light intensity, wherein when the first light intensity is converted to the second light intensity, the computing unit records a first time, and the rotation angle of the light beam corresponding to the first time is recorded as a first rotation angle, and when the first light intensity is converted into the third light intensity, the operation unit records as a second Time, and the rotation angle of the light beam corresponding to the second time is recorded as a second rotation angle, and the operation unit is based on the movement speed, the first rotation angle, the second rotation angle, the first time, The second time and the fixed distance are used to calculate the position of the wafer. The wafer positioning system of claim 4, wherein the laser scanning module comprises: a laser light source for emitting a light beam and traveling along a second light path; and a mirror And the second light path is configured to reflect the light beam to travel along the first light path; and a rotating braking unit is electrically connected to the mirror, and the mirror is disposed on the rotating braking unit, The rotating brake unit rotates at the rotation angle, and drives the mirror to rotate, so that the light beam is scanned on the wafer and the shipping unit at the rotation angle. The wafer positioning system of claim 4, further comprising a scattering bottom surface disposed under the shipping unit, the light beam traveling along the first light path and not being associated with the shipping unit and the wafer Rendezvous, the light beam advances To the bottom of the scattering, a scattered light is generated, wherein the intensity of the scattered light is the first light intensity. The wafer positioning system of claim 4, wherein the position of the wafer is represented by a plurality of wafer edge coordinates, and the operating unit can calculate one of the wafers according to the edge coordinates of the wafers. Center position. The wafer positioning system of claim 7, wherein each of the wafer edge coordinates is represented by a horizontal coordinate and a vertical coordinate, the horizontal coordinate is based on the fixed distance, the first rotation angle, and the The second rotation angle is calculated, and the vertical coordinate is calculated by the moving speed, the first time, and the second time.