Source: https://patents.google.com/patent/KR20070058354A/en
Timestamp: 2020-08-08 04:41:16
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KR20070058354A - Method for determining position of semiconductor wafer, and apparatus using the same - Google Patents
Method for determining position of semiconductor wafer, and apparatus using the same Download PDF
KR20070058354A
KR20070058354A KR1020060120522A KR20060120522A KR20070058354A KR 20070058354 A KR20070058354 A KR 20070058354A KR 1020060120522 A KR1020060120522 A KR 1020060120522A KR 20060120522 A KR20060120522 A KR 20060120522A KR 20070058354 A KR20070058354 A KR 20070058354A
KR1020060120522A
2005-12-02 Priority to JPJP-P-2005-00349076 priority
2006-12-01 Application filed by 닛토덴코 가부시키가이샤 filed Critical 닛토덴코 가부시키가이샤
2007-06-08 Publication of KR20070058354A publication Critical patent/KR20070058354A/en
230000002093 peripheral Effects 0.000 claims abstract description 78
A method for determining a position of a semiconductor wafer and an apparatus using the same are provided to determine a handling position of the semiconductor wafer in good accuracy by accurately obtaining a position of a detection site formed on a peripheral edge of the semiconductor wafer. A peripheral edge of a semiconductor wafer having a protective sheet is irradiated with light from a light source(25). The light from the light source is detected by a first detection member while the peripheral edge of the semiconductor wafer is irradiated with the light from the light source. A center of the semiconductor wafer is determined based on a result of the detection by the first detection member. The peripheral edge of the semiconductor wafer is irradiated with light from a light source. Light reflected from the semiconductor wafer is detected by a second detection member while the peripheral edge of the semiconductor wafer is irradiated with the light from the light source. A position of the detection site is determined based on a variation in intensity of the reflection light detected by the second detection member.
METHOD FOR DETERMINING POSITION OF SEMICONDUCTOR WAFER, AND APPARATUS USING THE SAME}
1 is a perspective view showing a schematic configuration of a semiconductor wafer used in this embodiment.
2 is a cross-sectional view of a semiconductor wafer.
3 is a plan view showing a schematic overall configuration of a positioning device of a semiconductor wafer according to the present embodiment;
Fig. 4 is a side view showing the main part configuration of the positioning device.
5 illustrates a rotation operation of a semiconductor wafer.
6 is a schematic diagram showing a state of a wafer during arithmetic processing.
7 is a schematic diagram showing a state of a wafer during arithmetic processing.
8 illustrates a field of view image of an optical camera.
9 is a side view illustrating a schematic configuration of a conveyance mechanism.
Fig. 10 is a flowchart showing processing of the embodiment apparatus.
1: expect
2: rotating mechanism
4: lifting drive mechanism
6: adsorption hole
7: holding stage
8: stage support
9: pulse motor for rotation
10: arithmetic processing unit
12: X axis stage
13: Y axis stage
14: X axis linear guide
15: X axis pulse motor
17: Y axis pulse motor
21: light receiving sensor
Reference Document 1 Japanese Unexamined Patent Publication No. Hei 8-279547
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a semiconductor wafer positioning method and an apparatus using the same, which detect a detection portion such as a notch or an orientation flat formed on the periphery of a semiconductor wafer with a protective sheet to determine a handling position of the semiconductor wafer.
The semiconductor wafer (hereinafter simply referred to as "wafer") is subjected to backside processing by a mechanical method such as grinding or polishing, or a chemical method using etching, and the thickness thereof becomes thin. In addition, when processing a wafer using these methods, a protective sheet is attached to the surface in order to protect the wafer surface on which the wiring pattern is formed. Then, the wafer with the protective sheet attached and polished is subjected to rotational scanning so as to pass through the gap between the light source and the light receiving sensor which are arranged opposite each other with the peripheral edge thereof, thereby obtaining positional information of the peripheral edge. The center position of the wafer can be obtained based on the positional information.
In addition, the center position of the wafer is determined, and the positional information of the detection site used for positioning such as notches and orientation flats is obtained, and the handling position of the wafer is determined based on the information. That is, based on the position of the detection site, the handling position is determined in consideration of the handling position at the time of conveyance or the rotational direction around the center axis of the wafer when the adhesive holding is held from the back surface of the wafer to the ring-shaped frame by the supporting adhesive tape. (See, for example, Japanese Patent Application Laid-open No. Hei 8-279547).
In recent years, after a rough circular protective sheet which covers the surface is ground, and the like is ground to thin the semiconductor wafer, a film is formed by depositing a metal on the processed back surface side. In such a case, since the protective sheet is exposed at the notch portion formed on the wafer, the film is attached to the exposed portion. In addition, the deposited metal and the like are solidified at the outer peripheral portion of the wafer due to the surface tension.
For this reason, even if light is irradiated to the outer periphery of a wafer, the film | membrane permeate | transmits light by a film in a notch part. Therefore, there is a problem that the light receiving sensor disposed to face each other with the wafer interposed therebetween cannot detect the transmitted light from the light source with high accuracy and cannot find the position of the notch.
In addition, when the light is irradiated from the back surface of the wafer and the position of the notch is detected by the light intensity of the reflected light, there is a problem that the light is diffusely reflected by the metal solidified around the wafer, so that only the notch portion can not be precisely specified.
SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and provides a semiconductor wafer positioning method and apparatus using the same, which can accurately determine the position of the detection site on the periphery of a semiconductor wafer with a protective sheet and determine the handling position with high accuracy. It is main purpose to do it.
The present invention adopts the following configuration to achieve this object.
In the positioning method of the semiconductor wafer which detects the position detection detection part in the peripheral part of the semiconductor wafer with a protective sheet, and determines a handling position,
A first irradiation step of irradiating light from a light source toward a peripheral portion of the semiconductor wafer with a protective sheet;
A light-receiving process of detecting light from the light source by first detection means disposed opposite the light source with the semiconductor wafer interposed while the light is being irradiated from the light source toward the peripheral portion of the semiconductor wafer;
A center determination process of determining a center position of the semiconductor wafer using the detection result by the first detection means;
A second irradiation step of irradiating light from a light source toward a peripheral portion of the semiconductor wafer,
A reflected light detection process of detecting, by the second detecting means, the reflected light reflected from the semiconductor wafer while the light is irradiated from the light source toward the peripheral portion of the semiconductor wafer;
And a detection site determination process of determining the position of the detection site based on the change in the light intensity of the reflected light detected by the second detection means.
According to the positioning method of the semiconductor wafer of this invention, the 1st detection means can detect the light which passed along the peripheral part of the semiconductor wafer by the light source and the 1st detection means which opposingly arranged the semiconductor wafer between them. For example, even when a film is provided in the peripheral portion of the semiconductor wafer, the first detection means can detect the light passing through the semiconductor wafer edge without being affected by the film. Therefore, the positional information of the outer peripheral end of the semiconductor wafer can be obtained from the position of the light detected by the first detecting means, and the center position can be obtained from this positional information.
In addition, the reflected light reflected at the peripheral portion of the semiconductor wafer changes depending on the state of the reflecting surface. That is, the light intensity detected by the second detection means is changed in the detection site having the reflective surface different from the semiconductor wafer. Therefore, the position of a detection site | part can be calculated | required using this change of light intensity.
That is, even if the film etc. are processed to the surface of a semiconductor wafer, since both the center position of a semiconductor wafer and the position of a detection site can be calculated | required with high precision, a handling position can be determined with high precision.
Further, in the light receiving process and the reflected light detection process, it is preferable to relatively rotate the light source, the set of the first detection means, and the semiconductor wafer about the central axis of the semiconductor wafer.
Moreover, it is more preferable to comprise the said invention method as follows.
In addition, the detection site in the peripheral part of a semiconductor wafer is a notch, for example.
In the center positioning process, for example, the center position is determined as follows.
Coordinate-convert the position of light detected along the circumference of the semiconductor wafer by the first detecting means,
Calculating the distance from the coordinates of one point arbitrarily determined on the surface of the semiconductor wafer to each coordinate of the peripheral edge of the semiconductor wafer,
The center coordinates are determined based on the change amount of the obtained distance data group.
In addition, the 2nd detection means used in a detection site determination process is imaging means, such as a CCD camera, for example.
In the detection site determination process, the position of the notch is determined as follows.
The peripheral portion of the semiconductor wafer irradiated with light from the light source is picked up by the imaging means,
The reference image data of the predetermined notch portion and the actual image data obtained by the imaging means are compared to determine the position of the notch in the peripheral portion of the semiconductor wafer.
According to this method, the coordinate data group of the outer peripheral end of a semiconductor wafer can be acquired by coordinate-converting the position of the light detected by the 1st detection means. And the distance from arbitrary coordinates can be calculated | required for every coordinate of the outer periphery edge part of a semiconductor wafer using the coordinate of the point arbitrarily determined on the surface of a semiconductor wafer, and the coordinate data group calculated | required previously. The center coordinates of the semiconductor wafer can be determined by using the amount of change in the distance data to be obtained.
Moreover, when light is irradiated to the outer peripheral part of a semiconductor wafer, light is reflected in the part and notch part of a semiconductor wafer, and it enters into an imaging means. That is, the light intensity of the reflected light incident on the imaging means is different in the outer peripheral part and the notch part of the semiconductor wafer, and real image data reflecting this change can be obtained. Then, the real image data and the reference image data of the predetermined notch can be compared to obtain a portion where the shapes coincide with each other, and the portion of the notch in the outer peripheral portion of the semiconductor wafer can be determined.
The position of the notch is preferably determined by pattern matching between the reference image data and the actual image data.
Moreover, the film which interrupts light transmission may be provided in the semiconductor wafer with a protective sheet on the back surface and the back surface of the protective sheet exposed by the notch part.
In this case, even if the film which obstruct | transmits light transmission is provided in the back surface of the semiconductor wafer and the back surface of the protective sheet exposed by the notch part, the 1st detection means can detect the light which passed along the outer periphery of a semiconductor wafer with high precision. Moreover, even if a film is provided in a protective sheet, the state of the reflecting surface differs from the state of the reflecting surface of a semiconductor wafer. Therefore, since a change occurs in the light intensity of the reflected light, the position of the detection site can be accurately obtained based on this change.
In particular, in the case of a coated semiconductor wafer, it is preferable to detect the reflected light by the second detecting means in a state where a white sheet or plate is disposed opposite the light source with the semiconductor wafer interposed therebetween.
According to this method, by arranging a white sheet or plate opposite the light source with the semiconductor wafer interposed therebetween, the edges of the outer circumference of the semiconductor wafer can be emphasized by the light reflected from the white surface.
Moreover, when using this method, it is preferable that the light source is a light source arrange | positioned facing a 1st detection means, is a separate light source, is arrange | positioned at the 2nd detection means side, and it is possible to change the irradiation angle of the light to a semiconductor wafer.
The present invention takes the following configuration to achieve this object.
In the positioning device of the semiconductor wafer which detects the detection position for positioning in the peripheral part of the semiconductor wafer with a protective sheet, and determines the handling position,
Holding means for holding a semiconductor wafer with the protective sheet;
First detection means arranged to face the light source with the semiconductor wafer interposed therebetween to detect a position of light irradiated from the light source;
Rotational movement means for relatively moving the light source, the set of the first detection means and the holding means so that the set of the light source and the first detecting means moves along the peripheral portion of the semiconductor wafer held by the holding means;
Second detection means for detecting the reflected light reflected from the semiconductor wafer among the light irradiated to the peripheral portion of the semiconductor wafer from the light source;
The second detection is performed while obtaining the center position of the semiconductor wafer based on the light detected by the first detecting means while relatively moving the light source, the light receiving means and the holding means by the rotation moving means. Computing means for obtaining the position of the detection site based on a change in the light intensity of the reflected light detected by the means;
And control means for controlling the rotational movement means to perform the alignment of the handling of the semiconductor wafer held by the holding means in accordance with a calculation result of the calculating means.
According to this configuration, the set and the holding means are moved relatively so that the light source and the set of the first detection means which are disposed to face each other with the semiconductor wafer therebetween move along the outer circumference of the semiconductor wafer. In the movement process, the light passing along the outer periphery of the semiconductor wafer can be detected by the first detecting means. In the movement process, the reflected light reflected from the outer peripheral portion of the semiconductor wafer can be detected by the second detecting means.
Therefore, the calculating means obtains the center position of the semiconductor wafer using the position of the light detected by the first detecting means, and calculates the position of the detection site based on the change in the light intensity of the reflected light detected by the second detecting means. Can be. By using the center position of the semiconductor wafer obtained by these calculation means and the position of the detection site, the control means can control the rotation movement means to move the semiconductor wafer to any handling position.
That is, according to this structure, the center position of a semiconductor wafer and the position of a detection site can be calculated | required with high precision, and the said invention can be implement | achieved suitably.
Then, the calculating means finds the center position of the semiconductor wafer and the position of the notch as follows.
The center position coordinates the position of light detected along the circumference of the semiconductor wafer by the first detecting means,
Determine the center coordinates based on the change amount of the obtained distance data group,
The position of the detection unit is to pick up the peripheral portion of the semiconductor wafer irradiated with light from the light source by the imaging means,
The position of the notch in the peripheral part of the said semiconductor wafer is calculated | required by comparing the reference image data of a predetermined notch part with the real image data obtained by the said imaging means.
In this case, it is preferable that the calculating means determines the position of the notch by pattern matching of the reference image data and the real image data.
In addition, according to the invention of the apparatus, the light source comprises a first light source disposed opposite the first detection means with the semiconductor wafer interposed therebetween, and a second light source for irradiating light to the peripheral portion of the semiconductor wafer. It is preferable to dispose a white sheet or plate opposite to the second light source with the gap therebetween.
According to this structure, conditions, such as the output of each light source, an irradiation angle, can be adjusted arbitrarily. Further, by arranging a white sheet or plate facing the light source with the semiconductor wafer interposed therebetween, the edge of the outer circumference of the semiconductor wafer can be emphasized by the light reflected from the white surface.
While some forms of what are presently considered suitable for describing the invention are shown, it is to be understood that the invention is not limited to the configuration and measures as shown.
EMBODIMENT OF THE INVENTION Hereinafter, the Example of the positioning device of the semiconductor wafer which is one Embodiment which can implement this method with reference to drawings is demonstrated.
In addition, the semiconductor wafer (henceforth simply a "wafer") of this embodiment is attached with the substantially circular protective sheet P which covers the surface in which the circuit pattern was formed, as shown in FIG. In this state, the back surface is ground and the like, and after the thin working of the wafer W is performed, the metal M is deposited on the back surface. Therefore, the metal M is also deposited on the back surface of the protective sheet P exposed at the V notch K portion of the detection site for determining the handling position formed on the wafer W. Further, due to the surface tension of the deposited metal M, the metal M is in a solid state as shown in FIG. Hereinafter, the specific structure of this embodiment apparatus is demonstrated. In addition, V notch K corresponds to the notch of this invention.
Fig. 3 is a plan view of the semiconductor wafer positioning device according to the embodiment of the present invention, and Fig. 4 is a side view showing the configuration of main parts of the semiconductor wafer positioning device.
As shown in Figs. 3 and 4, the device for determining the center of the semiconductor wafer of the present invention is a rotary mechanism for holding and rotating the back surface of the wafer W with the pattern surface on which the protective sheet P is attached upward ( 2), the rotation angle of the 1st peripheral measuring mechanism 3 and the 2nd peripheral measuring mechanism 36 which measure the peripheral edge of the wafer W hold | maintained by the said rotating mechanism 2, and the rotating mechanism 2 And an arithmetic driving unit 10 (not shown) for collecting predetermined positional data of the wafer W corresponding to the rotational angle and performing a predetermined calculation, and a lifting and lowering drive for allowing the rotary mechanism 2 to move up and down with respect to the rotational axis. The mechanism 4 and the conveyance mechanism 5 which carry in and take out the wafer W to the rotating mechanism 2 are comprised.
Moreover, the rotation mechanism 2 is corresponded to the rotation movement means of this invention.
The rotating mechanism 2 includes a cylindrical holding stage 7 for sucking the back surface of the wafer by the suction hole 6 formed on the upper surface thereof, and a stage supporting portion for rotatably holding the holding stage 7. It consists of 8). In addition, the holding | maintenance stage 7 is corresponded to the holding means of this invention.
Moreover, the rotary pulse motor 9 is provided continuously below the holding | maintenance stage 7, and the rotation mechanism 2 is rotatable by the drive of the said pulse motor 9 for rotation. In addition, the rotary pulse motor 9 is fixed to the lift drive mechanism 4. Moreover, the digital signal is transmitted from the rotating pulse motor 9 to the arithmetic processing part 10 mentioned later for every fixed rotation angle. Moreover, as a fixed rotation angle, it is 0.036 degree, for example, and the rotation mechanism 2 rotates once, the digital signal of 1000 pulses is transmitted to the arithmetic processing part 10 with which the controller 41 was equipped. In addition, a suction device (not shown) communicates with the suction hole 6 through the hole 11 of the stage support part 8. That is, a suction force for sucking the wafer W is applied to the suction hole 6 from the suction device.
The lift drive mechanism 4 is composed of an X-axis stage 12 that is slidable in the X-axis direction shown in the drawing, and a Y-axis stage 13 that is movable in the Y-axis direction. The X-axis stage 12 is mounted on the X-axis linear guide 14 attached to the base 1 of the apparatus, and is driven by the drive of the X-axis pulse motor 15 fixed to the base 1. It is provided so that a movement to an X-axis direction is possible.
The Y-axis stage 13 is mounted on the Y-axis linear guide 16 attached to the X-axis stage 12 and driven by the Y-axis pulse motor 17 fixed to the X-axis stage 12. It is installed to be movable in the Y-axis direction. The stage support 8 and the rotating pulse motor 9 are fixed to the Y-axis stage 13.
The first peripheral measurement mechanism 3 is provided on the side of the holding stage 7. Moreover, the 1st peripheral measuring mechanism 3 is comprised from the substantially L-shaped cylinder 18, the mirror 19 interposed in the said cylinder 18, the lens 20, and the light receiving sensor 21. have. In addition, the light receiving sensor 21 corresponds to the 1st detection means of this invention.
The mirror 19 is disposed in a substantially L-shaped refraction portion of the cylinder 18, and the front side in the figure is used to reflect the light incident from the upper opening of the cylinder 18 toward the light receiving sensor 21 on the right side in the figure. It is fixedly inclined at 45 degrees.
The light receiving sensor 21 is fixed to the edge part in the longitudinal direction of the cylinder 18 which is a side of the mirror 19. In addition, the lens 20 is fixedly disposed between the mirror 19 and the light receiving sensor 21 in the cylinder 18 so as to focus the reflected light from the mirror 19 to the light receiving sensor 21. The light receiving sensor 21 is a one-dimensional line sensor in which a plurality of light receiving elements are arranged on a straight line, and transmits the light receiving data received by the line sensor to the arithmetic processing unit 10 described later.
In addition, the 1st peripheral measuring mechanism 3 is being fixed to the measuring stage 22 movable in the radial direction of the rotating mechanism 2 shown by the arrow of the horizontal direction of FIG. The measuring stage 22 is mounted on the measuring linear guide 23 attached to the base 1. That is, the 1st peripheral measuring mechanism 3 is comprised so that the measuring stage 22 may move to the radial direction of the rotating mechanism 2 by the drive of the pulse motor 24 for a measurement. Moreover, the light source 25 which transmits light toward the periphery of the wafer W is arrange | positioned at the measuring stage 22. As shown in FIG.
The light source 25 is provided above the periphery of the wafer W and the mirror 19 so that the position of the wafer W can be easily detected, and transmits light toward the periphery of the wafer W. That is, various conditions such as the wavelength band and voltage of the light source 25 are controlled from the control unit 40 so as to have a predetermined wavelength and light intensity according to the type of the protective sheet P attached to the surface of the wafer W. ), And the controller 41 controls the voltage and the wavelength band of the light source 25 based on the input condition. In this embodiment, a fluorescent tube that outputs white light having a wavelength of 300 to 800 nm is used. In addition, the light source 25 is corresponded to the 1st light source of this invention.
Moreover, the kind of protective sheet P includes the material, the color of a base material, the surface treatment state of a base material, the thickness of the protective sheet P, etc.
As shown in Figs. 3 and 4, the second peripheral measuring mechanism 36 faces the surface side of the wafer W and the optical camera 36A disposed to be capable of lifting up and down above the peripheral portion of the wafer W. As shown in Figs. The illuminating device 36B which irradiates light is provided. This lighting apparatus 36B is comprised so that the irradiation angle of light can be adjusted. The optical camera 36A corresponds to the second detection means and the imaging means of the present invention, and the illumination device 36B corresponds to the second light source of the present invention.
The arithmetic processing part 10 calculates the center position of the wafer W by a calculation, and calculates the position of the V notch K formed in the periphery of a wafer by arithmetic. These calculation results are converted into digital signals and transmitted to the rotating mechanism 2 and each pulse motor so that the handling of the wafer W is performed.
As shown in Fig. 5, the wafer center position is a light receiving voltage when light received by the light receiving sensor 21 is linearly received from the light source 25 to the periphery of the wafer while the holding stage 7 is rotated. Coordinates as positional information on the wafer peripheral edge are obtained. Then, after determining an arbitrary point from the surface of the wafer W, a plurality of distances from the peripheral edge to the arbitrary point are calculated. The center position is calculated | required by calculating the dispersion | variation of the distance data of a predetermined ratio from the largest among the obtained several distance data. In addition, determination of the center position of the wafer W is not limited to this calculation method, You may obtain | require using the least-square method.
In addition, the arithmetic processing part 10 binarizes the real image data of the outer peripheral part of the wafer W acquired by the optical camera 36A, for example, recognizes the shape of the outer peripheral end, and changes from the change of the outer peripheral end. The position of the V notch K is specified. Subsequently, further, real image data of the V notched portion is obtained, and the actual image data of the V notched portion and the reference image data of the V notched portion acquired from the same reference wafer W as the measurement target previously stored in the storage unit 37 are used. Pattern matching is performed to calculate the position of the V notch K. FIG. This pattern matching is performed using, for example, binarization processing or normalized correlation search. Here, in the case of this embodiment, calculation of the position of the V notch K is performed as follows, for example. In this case, the position of the V notch K is obtained using the center coordinates of the obtained wafer W.
First, the peripheral part of the wafer W is picked up by the optical camera 36A at predetermined pulse intervals during the one rotation scan of the holding stage 7 to obtain real image data. At this time, a digital signal representing the rotation angle sent from the rotating pulse motor 9 is stored in the controller in association with each real image data. Each of these acquired real image data is binarized to specify the change of the V notch K portion, and to specify the real image data including the V notch K. FIG. Then, from the digital signal transmitted from the rotating pulse motor 9 at the time of acquiring the specified image data, it is calculated | required in the position with the V notch K of the present time. As a result, when the V notch K is present at the position shown in Fig. 6, the amount of shift from the position of the real image data including the V notch K to the shooting position in correspondence with the reference position data of the optical camera 36A. To calculate. That is, as indicated by the dashed-dotted line in Fig. 7, the holding stage 7 is rotated to the photographing position so that the V notch K enters the field of view 38 of the optical camera 36A.
Here, real image data of the peripheral part of the wafer W is acquired again. Pattern matching is performed using the real picture data and the reference picture data stored in the storage unit 37 to obtain the position coordinates of the existing V notches K. FIG. Here, the shift amount when the position of the V notch K is shifted to the right with respect to the longitudinal center axis Y of the visual field 38 of the optical camera 36A is calculated as shown in FIG.
For example, the lower right corner in the drawing of the field of view 38 of the optical camera 36A is referred to as the reference coordinate (0, 0) and the field of view width in the X-axis direction is XW, and the V notch ( When the vertex of K) is located at XP, the shift amount XN from the viewing center Y (XW / 2) on the X axis is represented by the following equation (1).
XN = (XW / 2-XP) x (pixel size in the X direction). (One)
In this case, since the Y-axis coordinates become substantially the same as the wafer radius, it is assumed that the deviation amount of the allowable range.
At this time, since the center of the wafer W is turned left by the rotation angle A1 as shown in Fig. 7, the center coordinates XC1 and YC1 after the rotational movement are obtained by the following equations (2) and (3). Can be.
XC1 = XC0 x cos (A1)-YC0 x sin (A1)... (2)
YC1 = XC0 x sin (A1) + YC0 x cos (A1)... (3)
In addition, A1 obtains the V notch K from the number of pulses for each imaging timing.
Next, the rotation angle AN of the coordinates XN and YN of the V notch K when it sees from the center coordinates XC1 and YC1 after rotation movement is calculated | required. Here, the radius of the wafer W is set to WR, and is obtained by the following equation (4).
AN = atan [(YN-YC1) / (XN-XC1)] = atan [(WR-YC1) / (XN-XC1)]... (4)
Next, the rotation angle AD as a correction amount for correcting the position of the V notch K is obtained by the following equation (5).
AD = -AN + (offset angle). (5)
Here, the offset angle is as much as the holding stage 7 is rotated for a distance longer than one rotation during the alignment execution due to the slow stop of rotational scan or the like.
Here, the rotation pulse number TP for correction | amendment is calculated | required by following formula (6).
TP = AD / (rotation angle per pulse)... (6)
Since the position of the V notch K is rotated by the rotational angle AN, and the rotational angle AD as much as considering the offset is required, the rotational angle A necessary for the rotation of the rotational angle A is required. = AN + AD, and the correction center coordinates (XD, YD) of the wafer after rotation are obtained by the following equations (7) and (8).
XD = XC0 × cos (A)-YC0 × sin (A)... (7)
YD = XC0 x sin (A) + YC0 x cos (A). (8)
Here, the coordinates XC0 and YC0 are center coordinates obtained by calculation first using the transmission method.
In order to correct the shift amounts in the X and Y axis directions of the center position and the V notches obtained as described above, the number of pulses XP and YP for driving the X and Y axis pulse motors 15 and 17 is XP =- It is calculated as the movement amount per XD / 1 pulse, and YP = the movement amount per -YD / 1 pulse.
The obtained pulse number is output from the controller 41 to each pulse motor. The movement amount for position correction is calculated | required above.
Next, as shown in FIG. 9, the conveyance mechanism 5 carries out the adsorption | suction groove 26 which adsorbs-holds the surface of the protective sheet P adhering to the surface in which the pattern of the wafer W was formed at the time of wafer conveyance. It consists of a horseshoe-shaped robot arm 27 and an arm movement table 28 which can freely move the robot arm 27 in the vertical direction.
The arm movement table 28 includes a Z axis stage 30 installed on the carrier base 29 so as to be movable in the up and down direction, a θ axis stage 31 rotatably installed on the Z axis stage 30, and θ. It consists of the R-axis stage 32 provided in the (theta) -axis stage 31 so that advancing to the radial direction of the axial stage 31 is possible. Here, the Z-axis stage 30, the θ-axis stage 31, and the R-axis stage 32 are respectively mounted on the Z-axis pulse motor 33 and the Z-axis stage 30 that are fixed to the carrier base 29. The fixed θ-axis pulse motor 34 and the R-axis pulse motor 35 fixed to the θ-axis stage 31 are provided to be movable or rotatable.
All of the above-described pulse motors control the controller 41 so that the rotation or movement of the holding stage 7, the X axis stage 12, the Y axis stage 13, the measuring stage 22 and the robot arm 27 is controlled. ) In addition, the controller 41 is provided with the arithmetic processing part 10, and is connected to the arithmetic processing part 10 in order to control each pulse motor by the arithmetic result of the light receiving sensor 21. As shown in FIG.
First, an initial condition necessary for alignment of the wafer W is set in the controller 41 by operating the operation unit 40. As initial conditions, the diameter of the wafer W, the material of the base material of the protective sheet P, the total thickness of the protective sheet, the color of the base material, the material of the film, the thickness, the imaging timing of the optical camera 36A, etc. Is set. When the initial setting is completed, each pulse motor is driven, and each of the rotary mechanism 2, the first peripheral measurement mechanism 3, and the lift drive mechanism 4 is operated to adjust the scan start position (step S1).
When the adjustment of the scanning position is completed, the robot arm 27 provided with the conveyance mechanism 5 by adsorption holding | maintenance is taken out from the back surface by the wafer W accommodated in the multistage in a horizontal state at predetermined intervals in the cassette which is not shown in figure. Then, it is loaded on the holding stage 7 of the positioning device of the semiconductor wafer (step S2).
When loaded onto the holding stage 7, the wafer W is subjected to about one rotational scan including an offset portion around the central axis of the holding stage 7 in the suction holding state. With this rotational scan, light is transmitted from the light source 25 toward the periphery of the wafer W, and data of the received light voltage is linearly transmitted from the light receiving sensor 2l to the calculation processing unit 10 (step S3A).
When the rotational scan is finished, the arithmetic processing part 10 calculates the position coordinate of the center of the wafer W using the acquired light-receiving voltage (step S4).
Further, at the same time as the rotational scan, light is irradiated to the outer peripheral portion of the wafer W by the illumination device 36B from the inclined upper side of the wafer W, and the wafer (at a predetermined time interval by the optical camera 36A). The peripheral portion of W) is picked up to acquire the actual image data (step S3B).
When the rotational scan is finished, the outer peripheral end portion of the wafer W is recognized from the respective actual image data acquired by the arithmetic processing unit 10, and the actual image data having a change is specified at the outer peripheral end portion of the V notch portion, and the actual image data and The shift amount (number of pulses) between the digital signal sent from the corresponding rotating pulse motor 9 and the photographing position of the optical camera 36A is obtained (step S5).
The holding stage 7 is transmitted from the controller 41 to the rotating pulse motor 9 from the controller 41 so that the portion of the V notch K enters the field of view of the optical camera 36A. Is driven to rotate (step S6).
When the rotational drive of the holding stage 7 is completed, the controller 41 operates the optical camera 36A to capture the peripheral part of the wafer W including the V notch K to acquire the actual image data. (Step S7).
The positional coordinates of the V notches K are obtained by pattern matching between the real picture data and the reference data previously stored in the storage unit 37. Then, using the positional coordinates of the center of the wafer W obtained by the arithmetic processing unit 10 in the previous step S4 and the above-described equations, the movement amount for correcting the V notch K to the reference position is calculated (step S8). .
The controller 41 drives and controls the X-axis pulse motor 15 and the Y-axis pulse motor 17 on the basis of the obtained movement amount of the wafer W, respectively, of the X-axis stage 12 and the Y-axis stage 13. Move to adjust the center position of the wafer (W). At the same time, the holding stage 7 is rotationally controlled to adjust the V notch K to the reference position (step S9).
When the alignment is completed, the wafer W is sucked and held by the robot arm 27 and transferred from the holding stage 7 to a storage cassette (not shown) (step S10). This completes the series of operations.
As described above, according to the positioning device of the semiconductor wafer according to the present invention, even if a film is formed on the back surface of the wafer to prevent the transmission of light such as the metal M by vapor deposition or the like to the back surface of the protective sheet P, The center position and the position of the V notch (K) can be obtained with high precision. That is, since the position coordinates of the outer peripheral end of the wafer W can be accurately obtained by the transmission method using the light source 25 and the optical sensor 21, the center position of the wafer W can be accurately obtained. In addition, by using the reflected light by the optical camera 36A and the illuminating device 36B, the position of the V notch K which is a detection site provided in the outer periphery of the wafer W can be precisely determined from the amount of change of the reflected light. .
Therefore, the handling position of the wafer W can be accurately determined using the center of these wafers W and the position of the V notch K. FIG.
This invention is not limited to the thing of the Example mentioned above, It can also be modified as follows.
(1) In the above embodiment, the wafer W is provided with a film that prevents light such as metal on the back surface of the exposed protective sheet P of the V notch K portion as an example. It is applied to the base material of which is colored, and which does not transmit light, and is coat | covered with the opaque glass plate. Moreover, it is applicable also to the workpiece | work etc. which the detection site | part to position other than the wafer W is coat | covered by another member.
(2) In the above embodiment, as shown by the broken line in Fig. 3, a white object 39 such as a white sheet-like object or a plate may be disposed opposite the optical camera 36A with the wafer W interposed therebetween. In this case, the light irradiated from the illuminating device 36B toward the outer circumferential portion of the wafer W is reflected from the white matter through the outer circumferential end of the wafer, so that the image of the wafer W The outer circumferential end is highlighted. Therefore, the position of the V notch K can be easily specified, and the precision can be improved.
(3) In the above embodiment, after one rotational scan, after specifying the position of the V notch K, real image data of the outer peripheral portion of the wafer W of the portion including the V notch K is acquired again. Although there existed, the position of the V notch K may be calculated | required by pattern matching of the real image data acquired at the time of one rotational scan, and reference image data.
(4) In the said embodiment, although the light source 25 and the illumination device 36B are provided separately, you may comprise using a single light source. In this case, what is necessary is just to comprise so that the irradiation angle of the light source 25 may be changed so that light may be irradiated toward the surface of the wafer W. As shown in FIG.
The present invention can be embodied in other specific forms without departing from the spirit or essence thereof, and therefore, reference should be made to the appended claims rather than the foregoing description as illustrating the scope of the invention.
According to the present invention, a main object of the present invention is to provide a method for positioning a semiconductor wafer and an apparatus using the same, which can accurately determine the position of the detection site on the periphery of the semiconductor wafer with the protective sheet and determine the handling position with high accuracy.
And a detection site determination step of determining the position of the detection site based on the change in the light intensity of the reflected light detected by the second detection means.
2. The method of claim 1, wherein the light receiving process and the reflected light detection process cause the set of light sources, the first detection means, and the semiconductor wafer to rotate relative to the central axis of the semiconductor wafer.
The detection portion of the periphery of the semiconductor wafer is a notch,
In the center positioning process, coordinate transformation of the position of light detected along the periphery of the semiconductor wafer by the first detection means,
And the detecting site determining step determines the location of the notch based on the change in the light intensity of the reflected light detected along the peripheral portion of the semiconductor wafer by the second detecting means.
A method of positioning a semiconductor wafer, wherein the reference image data of a predetermined notch portion and actual image data obtained by the imaging means are compared to determine the position of the notch in the peripheral portion of the semiconductor wafer.
5. The method of claim 4, wherein the position of the notch is determined by pattern matching of the reference image data and the real image data.
The method of positioning a semiconductor wafer according to claim 1, wherein the semiconductor wafer with a protective sheet is provided with a film that prevents light transmission on the rear surface of the semiconductor wafer and the rear surface of the protective sheet exposed from the notched portion.
7. The method for positioning a semiconductor wafer according to claim 6, wherein the second detection means detects the reflected light in a state where a white sheet or plate is disposed opposite the light source with the semiconductor wafer interposed therebetween.
The position of the semiconductor wafer according to claim 7, wherein the light source that is disposed opposite to the first detection means is an individual light source, and is disposed on the side of the second detection means, and the irradiation angle of light to the semiconductor wafer can be changed. How to decide.
In the positioning device of a semiconductor wafer which detects the positioning detection part in the peripheral part of the semiconductor wafer with a protective sheet, and determines a handling position,
While the set of the light source, the light receiving means, and the holding means are relatively moved by the rotation movement means, the center position of the semiconductor wafer is determined based on the light detected by the first detection means, and the second Computing means for obtaining the position of the detection site based on a change in the light intensity of the reflected light detected by the detection means;
And control means for controlling the rotational movement means to align the handling position of the semiconductor wafer held by the holding means in accordance with a calculation result of the calculating means.
10. The device of claim 9, wherein the detection site at the periphery of the semiconductor wafer is a notch,
Coordinate transformation of the position of the light detected along the periphery of the semiconductor wafer by the first detecting means, calculating the distance from the coordinates of one point arbitrarily determined on the surface of the semiconductor wafer to each coordinate of the periphery of the semiconductor wafer, The center coordinates are determined based on the change amount of the distance data group, and the center position is obtained.
And positioning the notch on the basis of a change in the light intensity of the reflected light detected along the peripheral portion of the semiconductor wafer by the second detecting means.
The notch in the peripheral part of the semiconductor wafer by imaging the peripheral portion of the semiconductor wafer irradiated with light from the light source by the imaging means, comparing the reference image data of the predetermined notch portion with the real image data obtained by the imaging means. A semiconductor wafer positioning device for obtaining the position of the.
The semiconductor wafer positioning apparatus according to claim 11, wherein said calculating means determines the position of the notch by pattern matching between the reference image data and the real image data.
The light source according to claim 9, wherein the light source includes: a first light source disposed to face the first detection means with the semiconductor wafer interposed therebetween;
An apparatus for positioning a semiconductor wafer, comprising a second light source for irradiating light to a peripheral portion of the semiconductor wafer.
The semiconductor wafer positioning device according to claim 13, wherein the second light source is configured to be capable of changing an irradiation angle of light to a peripheral portion of the semiconductor wafer.
The semiconductor wafer positioning apparatus according to claim 14, wherein a white sheet or plate is disposed to face the second light source with the semiconductor wafer interposed therebetween.
KR1020060120522A 2005-12-02 2006-12-01 Method for determining position of semiconductor wafer, and apparatus using the same KR20070058354A (en)
JPJP-P-2005-00349076 2005-12-02
KR20070058354A true KR20070058354A (en) 2007-06-08
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JP3590916B2 (en) * 1995-12-28 2004-11-17 株式会社ニコン Positioning method
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