JP2004363218A - Pre-aligner equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide pre-aligner equipment wherein notch detection mistake to tolerance and eccentricity of a wafer is eliminated, a notch can be detected certainly and sensor position adjustment is simple. <P>SOLUTION: The pre-aligner equipment is provided with a wafer holding rolling mechanism which holds the wafer W on a table 1 and rotates it, a notch detection sensor 5 which consists of a light casting apparatus 5a which casts light to a peripheral part of the wafer W, and a photodetector 5b which receives the light at a notch position of the wafer W. In the pre-aligner equipment, diameter of a shaft of light of the photodetector 5b is made smaller than width of a notch opening portion. A sensor anchor block 6 is arranged as independent of the wafer holding rolling mechanism and fixes the notch detection sensor 5. A linear motor 7 performs rectilinear movement of the notch detection sensor 5 to radial direction of the wafer W. A pre-alignment controller 9 having notch positioning function controls the wafer holding rolling mechanism and the linear motor 7, calculates rotation position of the notch 8 from a signal of the notch detection sensor 5, and arranges the notch 8 at a prescribed position are installed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pre-aligner device for detecting and positioning a notch in a substantially circular semiconductor wafer.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a pre-aligner device for detecting and positioning a notch in a substantially circular semiconductor wafer, for example, there is a device disclosed in Patent Document 1. Hereinafter, the apparatus will be described with reference to FIGS.
[0003]
FIG. 6 is a plan view showing a part of the conventional pre-aligner device cut away. In FIG. 6, a pre-aligner device for a wafer W is rotatable with respect to a ring 10 held by a housing (not shown) via an arm or the like, and a rotating plate capable of rotating the surface of the wafer W on the same plane. SB, rotary plate driving means for driving the rotary plate SB to rotate, and chuck pieces 41 to 41 capable of pressing the end face of the wafer W toward the center of the wafer W and mounted on the rotary plate SB. 45, and chuck piece driving means (not shown) for linearly reciprocating the chuck pieces 41 to 45 toward the center of the wafer W.
Here, the rotating plate driving unit is a unit that rotationally drives the rotating plate SB, and includes a rotation motor 21, a first shaft 22, a first drive transmission gear 23 interlocked with the first shaft 22, and a first shaft 22. The second drive transmission gear (not shown) meshing with the second shaft 24, the first rotation drive roller 25 provided at the tip of the second shaft 24, the gear 23, and the second drive transmission gear It has a third shaft (not shown) interlocked therewith, and a second rotary drive roller (not shown) provided at the tip of the third shaft. The two rotary drive rollers transmit the rotational force of the rotation motor 21 to the rotary plate SB.
FIG. 6 shows a state in which only the chuck pieces 41, 43, and 44 of the chuck pieces 41 to 45 constituting the wafer gripping device grip the end face of the wafer W in such a configuration. The sensor SE is a light emitting / receiving device that includes a light emitter SE1 and a light receiver SE2 (not shown) and is installed at a position where a notch of the wafer W (a cut in an end surface of the wafer W) passes. The sensor SE is fixed to an arm (not shown).
[0004]
FIG. 7 is a plan view showing a part of the conventional pre-aligner apparatus, in which the chuck pieces 41 and 43 are separated from the end face of the wafer W, and the chuck pieces 42, 44 and 45 grip the end face of the wafer W. FIG. The chuck pieces 41 to 45 can press the end face of the wafer W toward the center of the wafer W. Of these, three chuck pieces apply pressure to the end face of the wafer W, so that the center of gravity of the wafer W is This is to match the center position of the gripping device.
Further, in the process of rotating the wafer W by driving the rotation motor 21, the notch provided at the edge of the wafer W also rotates, and the sensor SE is moved so as to sandwich the locus of rotation of the notch. The notch passes so as to cross the optical path of the light beam traveling toward the light emitter SE1 and the light receiver SE2, and the sensor SE detects the notch.
As described above, the conventional wafer pre-aligner apparatus grips the wafer W with the chuck piece so that the center of gravity of the wafer W coincides with the center position of the wafer gripping apparatus, and the notch provided at the edge of the wafer W The sensor SE is installed at a position where the laser beam passes, and the notch is detected by rotating the wafer by the rotation motor.
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2000-26912
[Problems to be solved by the invention]
However, in the conventional pre-aligner apparatus, the position of the sensor for detecting the notch is fixed, and the sensor position cannot be automatically adjusted in the direction toward the center of the wafer and outward from the center of the wafer. Alternatively, when the wafer is eccentric due to the difference in the pressure of each chuck piece for gripping the wafer, there is a problem that the notch at the edge of the wafer cannot be detected. In addition, since the notch size is about 1 mm, it is difficult to position the notch detection sensor when assembling the pre-aligner device.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and eliminates a notch detection error due to wafer tolerance and eccentricity, can reliably detect a wafer notch, and can easily adjust a sensor position. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, the present invention according to claim 1 has a wafer gripping / rotating mechanism capable of gripping and rotating a substantially circular wafer on a table having a vertical rotation axis, and throwing the wafer onto a peripheral portion of the wafer. In a pre-aligner apparatus including a notch detection sensor including a light projector that emits light and a light receiver that receives light at a notch position of the wafer, a beam diameter of the light receiver is set to be smaller than a width dimension of a notch opening. A sensor fixing table for fixing the notch detection sensor, and a linear movement for linearly reciprocating the notch detection sensor in the radial direction of the wafer. Controlling the operation of the apparatus, the wafer holding and rotating mechanism and the linear moving device, and calculating the rotational position of the notch from the signal of the notch detection sensor; A pre-alignment controller having a notch positioning function to place switch in position, in which with a.
[0009]
According to a second aspect of the present invention, in the pre-aligner apparatus according to the first aspect, when the signal of the notch detection sensor is not output, the pre-alignment controller moves the sensor position in the radial direction of the wafer until the sensor signal is output. It has means for sending a command to the linear moving device so as to move it.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is an overall perspective view of a pre-aligner apparatus showing an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a table having a wafer W and a wafer chuck mechanism 2 having a vertical rotation axis, reference numeral 2 denotes a wafer chuck mechanism capable of gripping a wafer end and moving the gripped wafer W in a vertical direction, and reference numeral 3 denotes a wafer chuck mechanism. A motor 4 for rotating the wafer chuck mechanism 2 holding the table 1 and the wafer W is an encoder for detecting a rotation angle of the motor 3, and the table 1, the wafer chuck mechanism 2, the motor 3, and the encoder 4 It constitutes a holding and rotating mechanism. Reference numeral 5 denotes a notch detection sensor for detecting the wafer notch 8, reference numeral 6 denotes a sensor fixing stand which is disposed separately from the wafer holding and rotating mechanism and fixes the notch detection sensor 5, and reference numeral 7 denotes the notch detection sensor 5 and the sensor. A linear motor 9 is a linear moving device that can reciprocate the fixed table 6 in the radial direction of the wafer W. The linear motor 9 controls the operation of the motor 3 and the linear motor 7, and further rotates the notch 8 based on a signal from the notch detection sensor 5. This is a pre-alignment controller having a notch positioning function of calculating a position and arranging the notch 8 at a predetermined position.
[0011]
FIG. 2 is a detailed explanatory diagram of the notch detection sensor in FIG.
5a is a light projector for projecting light to the peripheral portion of the wafer, 5b is a light receiver for receiving light at the notch position of the wafer, 5c supplies power to the light projector 5a and the light receiver 5b, and determines the presence or absence of the notch 8 from the light receiving signal. It is a sensor amplifier that outputs. Note that the light projector 5a and the light receiver 5b may be formed of optical fibers, and the sensor amplifier 5c may be provided with a light source and a light receiving sensor.
As shown in FIG. 2, the width of the light receiver 5b that receives light is generally called a beam diameter. If the beam diameter is larger than the width of the opening of the notch 8, the notch detection width becomes larger than the actual width of the notch due to the influence of the sneaking light on the light receiver 5b, so that the notch positioning accuracy deteriorates. For this reason, the beam diameter of the sensor 5 is set smaller than the width of the opening of the notch 8.
[0012]
FIG. 3 is an internal circuit block diagram of the sensor amplifier in FIG.
51 is a light emitting element, 52 is a light receiving element, 53 is a current commander, 54 is a current-voltage converter, 55 is a comparator, and 56 is a light projector ON-OFF controller.
When the projector ON-OFF controller 56 receives the projector ON signal from the pre-alignment controller 9, a current flows from the current commander 53 to the projector 51, and light is emitted from the projector 51. When the light from the light projecting element 51 is received by the light receiving element 51, the light is converted into a voltage signal by the current / voltage converter 54, converted into a digital signal by the comparator 55, and sent to the pre-alignment controller 9.
[0013]
FIG. 4 is a diagram showing an output signal of the notch detection sensor.
As shown in FIG. 4, the output signal of the sensor is "H" when there is a notch, and "L" when there is no notch. In addition, it is good also as "L" when there is a notch, and "H" when there is no notch. When the light projector 5a and the light receiver 5b are configured by optical fibers, the light projecting element 51 and the light receiving element 52 are configured inside the sensor amplifier 5c.
[0014]
FIG. 5 is a flowchart of a method for detecting and positioning a notch in a semiconductor wafer by a pre-aligner apparatus according to an embodiment of the present invention. Steps (means) shown in the flowchart below are those in which an operation command is issued by the pre-alignment controller 9.
First, in step ST1, the wafer W is transferred onto the table 1 by a robot hand (not shown) or the like, and the wafer chuck mechanism 2 grips the edge of the wafer W. The wafer chuck mechanism 2 above the wafer W moves in the direction of the wafer W, and grips the wafer W. Then, after the robot hand moves, the wafer chuck mechanism 2 moves downward. At this time, the center of gravity of the wafer W substantially coincides with the center position of the table 1.
Subsequently, in step ST2, preparation for measurement by the sensor 5 is performed.
In step ST3, the table 3 and the wafer chuck mechanism 2 holding the wafer W are rotated by the motor 3, and the position of the notch 8 in the rotation direction is measured by the encoder 4 and the notch detection sensor 5.
In step ST4, it is determined whether or not the rotational position of the notch 8 has been detected by the notch detection sensor 5. If detected, the process proceeds to step ST5. If not, the process proceeds to step ST7.
If the position of the notch 8 can be detected in step ST4, the motor 3 is rotated in step ST5 so that the notch position becomes a predetermined position.
In step ST6, after raising the wafer chuck mechanism 2, the wafer W is transferred to the robot hand, and a series of pre-alignment operations ends.
Next, if the notch position cannot be detected in step ST4, the process proceeds to step ST7, and in step ST7, it is determined whether the sensor output signal is “H” or “L”, and the sensor output signal is set to “H”. If "", the process proceeds to step ST8, and if the sensor output signal is "L", the process proceeds to step ST10. When the sensor output signal is "H" and there is no light-shielding object (wafer W) between the light emitter 5a and the light receiver 5b, the sensor output signal is "L" and the light-shielding object (light) between the light emitter 5a and the light receiver 5b. There is a wafer W).
Next, in step ST8, if the sensor output signal is “H” in step ST7, the sensor light receiving signal “L” is moved toward the wafer radial position where the sensor fixing base 6 can detect the notch 8 by the linear motor 7. The wafer W is moved in the inner circumferential direction until it is output.
Then, in step ST9, the sensor fixing base 6 is moved by the linear motor 7 in the inner circumferential direction of the wafer by about 1/2 of the notch depth width, and the process returns to step ST2.
If the sensor output signal is "L" in step ST7, in step ST10, the sensor fixing base 6 is moved by the linear motor 7 in the outer peripheral direction of the wafer until the sensor light receiving signal "H" is output.
Then, in step ST11, the sensor fixing base 6 is moved by the linear motor 7 in the inner circumferential direction of the wafer by about 1/2 of the notch depth width, and the process returns to step ST2. A series of prealigner operations described above are performed by instructions and calculations by the prealignment controller 9.
[0015]
Therefore, the embodiment of the present invention comprises a wafer gripping / rotating mechanism capable of gripping and rotating a substantially circular wafer W on a table 1 having a vertical rotation axis, and a projector 5a for projecting light to a peripheral portion of the wafer. In the pre-aligner device including the notch detection sensor 5 including the light receiving device 5b that receives light at the notch position of the wafer W, the beam diameter of the light receiving device 5b is set to be smaller than the width dimension of the notch opening. A sensor fixing base 6 for fixing the notch detection sensor 5 and a linear motor for linearly reciprocating the notch detection sensor 5 in the radial direction of the wafer W, while being disposed separately from the wafer gripping rotation mechanism; 7, the operation of the wafer gripping and rotating mechanism and the linear motor 7 is controlled, the rotational position of the notch is calculated from the signal of the notch detection sensor 5, and the notch 8 is located. A pre-alignment controller 9 having a notch positioning function be placed in position, so with a tolerance of the wafer outer dimensions, the notch detection error for the eccentricity of the grasped wafer can be prevented. Further, the notch of the wafer can be reliably detected, the position of the notch detection sensor can be easily and automatically adjusted, and the initial setting of the position of the notch detection sensor can be easily performed.
When the signal of the notch detection sensor 5 is not output, the pre-alignment controller 9 sends a command to the linear motor 7 to move the sensor position in the radial direction of the wafer until the sensor signal is output. With this configuration, it is possible to more reliably eliminate notch detection errors.
[0016]
Note that, instead of the linear motor 7, a sensor fixing base 6 may be linearly moved using a ball screw mechanism and a rotary motor.
Further, the flowchart of the pre-aligner apparatus shown in FIG. 5 can be applied to positioning of the notch detection sensor 5 at the time of assembling the pre-aligner apparatus.
Further, when positioning the notch detection sensor 5 at the time of assembling the pre-aligner apparatus, the wafer W is gripped by the wafer chuck mechanism 2 and the sensor fixing base 6 is moved to a wafer radial position where the notch 8 can be detected by the linear motor 7. Thus, the notch detection sensor 5 can be automatically positioned.
[0017]
【The invention's effect】
As described above, according to the pre-aligner apparatus of the present invention, a wafer gripping / rotating mechanism capable of gripping and rotating a substantially circular wafer on a table having a vertical rotation axis, and throwing the wafer onto the peripheral edge of the wafer. In a pre-aligner apparatus including a notch detection sensor including a light projector that emits light and a light receiver that receives light at a notch position of the wafer, a beam diameter of the light receiver is set to be smaller than a width dimension of a notch opening. A sensor fixing table for fixing the notch detection sensor, and a linear movement for linearly reciprocating the notch detection sensor in the radial direction of the wafer. And the operation of motors provided in the wafer gripping / rotating mechanism and the linear moving device, respectively. And a pre-alignment controller having a notch positioning function of calculating a rotational position of the notch and arranging the notch at a predetermined position, thereby preventing a notch detection error with respect to a wafer outer size tolerance and eccentricity of a gripped wafer. . Further, the notch of the wafer can be reliably detected, the position of the notch detection sensor can be easily and automatically adjusted, and the initial setting of the position of the notch detection sensor can be easily performed.
Further, the pre-alignment controller sends a command to the linear movement device to move the sensor position in the radial direction of the wafer until the sensor signal is output when the signal of the notch detection sensor is not output. , The notch detection error can be more reliably eliminated.
[Brief description of the drawings]
1 is an overall perspective view of a pre-aligner apparatus showing an embodiment of the present invention; FIG. 2 is a detailed explanatory view of a notch detection sensor in FIG. 1; FIG. 3 is a block diagram inside a sensor amplifier in FIG. 1; FIG. 5 is an explanatory diagram of an output signal of a detection sensor. FIG. 5 is a flowchart of a method for detecting and positioning a notch in a semiconductor wafer according to an embodiment of the present invention. FIG. FIG. 11 is a plan view showing a part of the conventional pre-aligner apparatus, in which the chuck pieces 41 and 43 are separated from the end faces of the wafer W and the chuck pieces 42, 44 and 45 are gripping the end faces of the wafer W. Indicating [Explanation of symbols]
Reference Signs List 1 Table 2 Wafer chuck mechanism 3 Motor 4 Encoder 5 Notch detection sensor 5a Projector 5b Receiver 5c Sensor amplifier 51 Projector 52 Projector 54 Current commander 54 Current-voltage converter 55 Comparator 56 Projector ON-OFF controller 6 Sensor fixed Stand 7 Linear motor (linear moving device)
8 notch 9 pre-alignment controller

Claims (2)

A wafer gripping and rotating mechanism capable of gripping and rotating a substantially circular wafer on a table having a vertical rotation axis, a light projector for projecting light to a peripheral portion of the wafer, and a light receiving device for receiving light at a notch position of the wafer A pre-aligner device having a notch detection sensor composed of a
The beam diameter of the light receiver is set smaller than the width of the notch opening,
Attached to the wafer gripping and rotating mechanism separately, and a sensor fixing table for fixing the notch detection sensor,
A linear moving device for linearly reciprocating the notch detection sensor in the radial direction of the wafer,
A pre-alignment controller having a notch positioning function of controlling the operation of the wafer gripping rotation mechanism and the linear movement device and calculating the rotational position of the notch from the signal of the notch detection sensor, and arranging the notch at a predetermined position; A pre-aligner device comprising: The pre-alignment controller, when the signal of the notch detection sensor is not output, sends a command to the linear movement device so as to move the sensor position in the radial direction of the wafer until the sensor signal is output. The pre-aligner device according to claim 1, further comprising:

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