CN111381451B - Pre-alignment system, pre-alignment method and photoetching equipment - Google Patents
Pre-alignment system, pre-alignment method and photoetching equipment Download PDFInfo
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- CN111381451B CN111381451B CN201811642976.3A CN201811642976A CN111381451B CN 111381451 B CN111381451 B CN 111381451B CN 201811642976 A CN201811642976 A CN 201811642976A CN 111381451 B CN111381451 B CN 111381451B
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
- G03F7/7085—Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7096—Arrangement, mounting, housing, environment, cleaning or maintenance of apparatus
Abstract
The invention provides a pre-alignment system, a pre-alignment method and a photoetching device, wherein a pre-alignment module is used for detecting position information and coding information of a silicon wafer, and an image acquisition module is used for acquiring the position information and the coding information of the silicon wafer and transmitting the position information and the coding information back to a central processing module; the central processing module is used for sending a motion instruction according to the position information of the silicon wafer, and the motion control module controls the pre-alignment module to move according to the motion instruction so as to pre-align the silicon wafer; and the central processing module is also used for carrying out coding identification on the silicon chip according to the coding information of the silicon chip. The central processing module controls the realization of the pre-alignment and the code identification of the silicon chip without coordination of other equipment, thereby not only saving the time of the pre-alignment and the code identification of the silicon chip, but also leading the pre-alignment system to have stronger functionality, not needing to additionally increase the equipment for the code identification of the silicon chip in the subsequent production process and reducing the cost of the equipment.
Description
Technical Field
The present invention relates to the field of semiconductors, and in particular, to a pre-alignment system, a pre-alignment method, and a lithographic apparatus including the pre-alignment system.
Background
A photolithography (photolithography) process is an important step in the manufacturing process of a semiconductor device, and generally includes processes of spin-coating a photoresist, exposing, developing, and the like. Generally, after a photoresist is spin-coated on a substrate (e.g., a silicon wafer, a glass substrate, etc.), a pattern on a photomask is transferred onto the photoresist using an exposure and development process, and then the pattern on the photomask is transferred onto the substrate through an etching process.
The pre-alignment system is an important component of the lithography equipment, and mainly acquires silicon wafer data through a Charge Coupled Device (CCD) image sensor, calculates a position deviation, and corrects the position deviation to achieve the purpose of accurately positioning the silicon wafer. Specifically, in the exposure process, after a silicon wafer is placed on a corresponding support surface of a lithography device, a pre-alignment system is required to pre-position the position of the silicon wafer and pre-orient the direction of the silicon wafer, and after the pre-alignment, silicon wafer codes (i.e., silicon wafer IDs) are identified, so that accurate exposure alignment is performed on batches of silicon wafers subsequently.
In the prior art, silicon chip ID recognition is finished by adopting a commercial bar code reader, the bar code reader is generally added on a pre-alignment system, after the pre-alignment is finished, the silicon chip is rotated to a certain angle and is lifted to a recognition height, and the bar code reader is utilized to recognize silicon chip ID characters.
Disclosure of Invention
The invention aims to provide a pre-alignment system, a pre-alignment method and photoetching equipment, which do not need to be additionally provided with a bar code reader and are beneficial to the overall occupied space and cost of the equipment.
To achieve the above object, the present invention provides a pre-alignment system comprising: the device comprises a central processing module, a motion control module, a pre-alignment module and an image acquisition module; the pre-alignment module is used for detecting position information and coding information of a silicon wafer, and the image acquisition module is used for acquiring the position information and the coding information of the silicon wafer and transmitting the position information and the coding information back to the central processing module; the central processing module is used for sending a motion instruction according to the position information of the silicon wafer, and the motion control module controls the pre-alignment module to move according to the motion instruction so as to pre-align the silicon wafer; and the central processing module is also used for carrying out coding identification on the silicon chip according to the coding information of the silicon chip.
Optionally, in the pre-alignment system, the pre-alignment module includes: a rotating table, a centering table and an optical detection element;
the rotating platform is used for adjusting the angle and the vertical position of the silicon wafer so as to deliver the silicon wafer to the centering platform;
the centering table is used for adjusting the horizontal position of the silicon wafer;
the optical detection element is used for detecting the position information and the coding information of the silicon chip, and the image acquisition module acquires the information detected by the optical detection element.
Optionally, in the pre-alignment system, the motion control module includes: the system comprises a motion control card, a plurality of motors and a plurality of servo amplifiers equipped for the motors;
the central processing module controls the plurality of servo amplifiers through the motion control card so as to control the plurality of motors.
Optionally, in the pre-alignment system, the plurality of motors include a first motor, a second motor, a third motor and a fourth motor, and the plurality of servo amplifiers include a first servo amplifier, a second servo amplifier, a third servo amplifier and a fourth servo amplifier;
the first motor is used for controlling the horizontal position of the centering table; the second motor is used for controlling the horizontal rotation angle of the rotating platform; the third motor is used for controlling the vertical position of the rotating platform; the fourth motor is used for controlling the horizontal position of the optical detection element.
Optionally, in the pre-alignment system, the central processing module and the motion control card perform information interaction through a first data transmission interface, and the motion control card controls the plurality of servo amplifiers through a local area network.
Optionally, in the pre-alignment system, the image acquisition module includes an image acquisition card, and the central processing module acquires information detected by the optical detection element through the image acquisition card.
Optionally, in the pre-alignment system, the central processing module and the image capture card perform information interaction through a second data transmission interface, and the image capture card controls the optical detection element through an image transmission network.
Optionally, in the pre-alignment system, the optical detection element is a line-to-plane switching optical detection element.
Optionally, in the pre-alignment system, the optical detection element includes a charge coupled device.
Optionally, in the pre-alignment system, the central processing module includes a central processor.
The invention also provides a lithographic apparatus comprising the above pre-alignment system.
The invention also provides a pre-alignment method, which comprises the following steps:
the pre-alignment module detects position information and coding information of a silicon wafer, and the image acquisition module acquires the position information and the coding information of the silicon wafer and returns the position information and the coding information to the central processing module;
the central processing module sends a movement instruction according to the position information of the silicon wafer, and the movement control module controls the pre-alignment module to move according to the movement instruction so as to pre-align the silicon wafer; and
and the central processing module carries out code identification on the silicon chip according to the code information of the silicon chip.
Optionally, in the pre-alignment method, the pre-alignment step of the silicon wafer includes implementing centering of the silicon wafer and implementing orientation of the silicon wafer.
Optionally, in the pre-alignment method, the centering of the silicon wafer includes the following steps:
s11: obtaining a silicon wafer to a rotating table in the pre-alignment module;
s12: adjusting an optical detection element in the pre-alignment module to be in a linear array mode, and detecting the position information of the silicon wafer;
s13: the central processing module calculates the circle center position of the silicon wafer according to the position information; and
s14: the central processing module sends a motion instruction according to the circle center position, and the motion control module controls the rotary table and the centering table in the pre-alignment module to move according to the motion instruction so as to realize the centering of the silicon wafer.
Optionally, in the pre-alignment method, implementing the orientation of the silicon wafer includes the following steps:
s21: the central processing module calculates the lowest position coordinate of the silicon chip notch according to the position information;
s22: the central processing module sends a motion instruction according to the information of the lowest position coordinate of the silicon chip notch, and the motion control module controls the rotary table to move according to the motion instruction, so that the lowest position of the silicon chip notch is rotated into the identification field of the optical detection element, and sampling is performed;
s23: the central processing module is used for positioning the sampling data to obtain the central angle of the silicon chip notch; and
s24: the central processing module sends a motion instruction according to the central angle information of the silicon chip gap, and the motion control module controls the rotation of the rotating platform according to the motion instruction so as to realize the orientation of the silicon chip.
Optionally, in the pre-alignment method, identifying the code of the silicon chip includes the following steps:
s31: the optical detection elements in the pre-alignment module are adjusted to be in an area array mode, and the central processing module controls the motion control module to move the optical detection elements to an identification position;
s32: the image acquisition module searches for a starting angle and an ending angle of the silicon chip code when the motion control module rotates the silicon chip;
s33: the motion control module rotates the silicon wafer back and forth, the image acquisition module acquires images and transmits the images back to the central processing module when the silicon wafer rotates back and forth, and the rotation range is from the starting angle to the ending angle; and
s34: and the central processing module processes the acquired image to acquire the coding information of the silicon chip.
Optionally, in the pre-alignment method, the positions on the silicon chip where the silicon chip codes are arranged include a first position and a second position;
the first position takes the central line of the silicon chip gap as an axis and is arranged in an axisymmetric manner;
the second position takes the silicon wafer radius with an included angle of 45 degrees with the center line of the silicon wafer gap as an axis and is arranged in an axisymmetric manner.
Optionally, in the pre-alignment method, before S32, the method further includes the following steps:
and the central processing module judges the position of the central line of the notch of the silicon chip and rotates the minimum angle to enable the identification view field of the optical detection element to be positioned in the range from the starting angle to the ending angle of the silicon chip code.
Optionally, in the pre-alignment method, in S34, the central processing module processes the acquired silicon chip encoded image, and mainly includes the following steps:
performing boundary extraction on the original image coded by the silicon chip to obtain a process image;
carrying out AND operation on the process image and the image original image to obtain a result image;
segmenting the result graph to obtain a single character result graph;
matching the single character result image with a template of the image original image; and
and splicing the single character result graphs after the matching is successful, thereby obtaining the coding information of the silicon chip.
In the pre-alignment system provided by the invention, the pre-alignment module is used for detecting the position information and the coding information of the silicon chip, and the image acquisition module is used for acquiring the position information and the coding information of the silicon chip and transmitting the position information and the coding information to the central processing module; the central processing module sends a motion instruction to the motion control module according to the position information of the silicon wafer, the motion control module can control the pre-alignment module to move according to the motion instruction so as to pre-align the silicon wafer, and the central processing module can also perform code identification (namely identify the ID of the silicon wafer) of the silicon wafer according to the code information of the silicon wafer. The central processing module controls the realization of the pre-alignment and the code recognition of the silicon chip without coordination of other equipment, thereby saving the time of the pre-alignment and the code recognition of the silicon chip, ensuring that a pre-alignment system has stronger functionality, not needing to additionally increase equipment (such as a bar code reader) for the code recognition of the silicon chip in the subsequent production process, reducing the cost of the equipment and being beneficial to solving the space occupation of the equipment.
Drawings
FIG. 1 is a diagram of a control architecture of a pre-alignment system provided by an embodiment of the present invention;
FIG. 2 is a block diagram of a pre-alignment module provided in an embodiment of the present invention;
FIG. 3 is a schematic diagram of silicon chip coded image acquisition according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a silicon chip notch and a local edge image according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a silicon chip encoded image according to an embodiment of the present invention;
FIG. 6 is a flow chart illustrating a pre-alignment method according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of finding a silicon chip coded image according to an embodiment of the present invention;
description of the labeling:
100-a central processing module; 200-a motion control module; 210-a motion control card; 221-a first servo amplifier; 222-a second servo amplifier; 223-a third servo amplifier; 224-a fourth servo amplifier; 225-a first motor; 226-a second motor; 227-a third motor; 228-a fourth motor; 300-an image acquisition module; 310-image acquisition card; 311-identifying the field of view; 312-identify angle; 313-character segmentation window; 314-silicon chip notch; 400-a silicon wafer; 411-a first arc; 412-second arc; 413-first position; 414-second position; 500-pre-alignment module; 511-centering table; 512-rotating table; 513-optical detection element.
Detailed Description
The following describes in more detail embodiments of the present invention with reference to the schematic drawings. Advantages and features of the present invention will become apparent from the following description and claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
In the following, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances. Similarly, if the method described herein comprises a series of steps, the order in which these steps are presented herein is not necessarily the only order in which these steps may be performed, and some of the described steps may be omitted and/or some other steps not described herein may be added to the method.
Generally, a silicon chip code (generally referred to as a silicon chip ID) for tracking and recording a processing process of the silicon chip is arranged on the silicon chip, and equipment needs to identify the silicon chip code in the processing process to ensure the correctness of the silicon chip process. Silicon chip IDs are generally divided into 12-character silicon chips and 18-character silicon chips, wherein the ID of 12 characters identifies the series of silicon chips produced in a factory, and the ID of 18 characters identifies a single independent silicon chip. The ID of the wafer contains some additional information such as the source of the wafer, the resistivity of the wafer, the dopant species of the wafer, and the crystal growth orientation. At present, a bar code reader is usually additionally arranged on a pre-alignment system of the photoetching equipment to complete the identification of the silicon chip ID, but the mode has the disadvantages of large occupied space and high cost of the equipment. In order to reduce the occupied space of the device as much as possible, reduce the cost and enhance the functionality of the pre-alignment system, the embodiment of the invention provides the pre-alignment system.
Fig. 1 is a control architecture diagram of a pre-alignment system according to an embodiment of the present invention, as shown in fig. 1, the pre-alignment system includes a central processing module 100, a motion control module 200, an image capture module 300, and a pre-alignment module 500. The motion control module 200 and the image acquisition module 300 are both in communication connection with the central processing module 100 for information interaction.
The central processing module 100 may send an image acquisition instruction to the image acquisition module 300 to prompt the image acquisition module 300 to acquire the position information and the coding information of the silicon wafer 400 detected by the pre-alignment module 500, and the image acquisition module 300 may transmit the acquired position information and the acquired coding information of the silicon wafer 400 back to the central processing module 100, where the position information includes, for example, edge information and gap information. The central processing module 100 may send a motion command to the motion control module 200 according to the position information of the silicon wafer 400, so as to control the pre-alignment module 500 to move as required through the motion control module 200, so as to pre-align the silicon wafer 400. Also, the motion control module 200 may transmit information before and after the pre-alignment module 500 moves back to the central processing module 100. The central processing module 100 is further configured to perform code identification on the silicon chip 400 according to the code information of the silicon chip 400.
Fig. 2 is a structural diagram of a pre-alignment module according to an embodiment of the invention, and as shown in fig. 2, the pre-alignment module 500 includes, for example, a rotation stage 512, a centering stage 511, and an optical detection device 513. The rotation stage 512 is used for adjusting the horizontal angle of the silicon wafer 400, so that the silicon wafer 400 can rotate the silicon wafer notch 314 or the silicon wafer code to the identification field 311 (see fig. 3) of the optical detection element 513, and is also used for adjusting the vertical position of the silicon wafer 400 to transfer the silicon wafer 400 to the centering stage 511. The centering table 511 is used to adjust the horizontal position of the silicon wafer 400. The optical detection element 513 is configured to detect position information and encoding information of the silicon chip 400, and the image acquisition module 300 acquires information detected by the optical detection element 513.
As an example, the rotating table 512, the centering table 511 and the optical detection element 513 may be connected to respective transmission units, each of which is connected to a motor, so as to realize the ascending/descending and rotating motion of the rotating table 512, the horizontal position movement of the centering table 511 and the horizontal position movement of the optical detection element 513 (i.e. to adjust the position of the recognition field 311). The turntable 512 is a cylindrical structure, for example. The centering station 511 comprises a platform having an opening in the middle or elsewhere, which is generally U-shaped. The turntable 512 may move up or down through the opening of the centering table 511, thereby transferring the silicon wafer 400 between the turntable 512 and the centering table 511.
Preferably, the optical detection element 513 is a line-to-plane switching optical detection element, and can be switched between a "line array mode" and an "area array mode"; adjusting to a linear array mode to detect edge information and/or gap information of the silicon wafer 400, so as to realize pre-alignment operation of the silicon wafer 400; and adjusting the silicon wafer to be in an area array mode to detect the coding information on the surface of the silicon wafer 400, so as to realize the identification of the coding of the silicon wafer 400. Further, the optical detection element 513 may be a line-surface switching charge coupled device.
In the pre-alignment system, the central processing module 100 may be a central processor for processing the received information and sending instructions to the motion control module 200 and the image capturing module 300.
The motion control module 200 primarily effects displacement of the pre-alignment module 500, e.g., adjustment in horizontal and vertical positions. Referring with emphasis to fig. 1, the motion control module 200 includes, for example: a motion control card 210, a plurality of motors, and a plurality of servo amplifiers provided for the plurality of motors, and the central processing module 100 controls the plurality of servo amplifiers through the motion control card 210 to control the plurality of motors. As an example, the motion control module 200 employs 4 motors and 4 servo amplifiers, where the 4 motors are a first motor 225, a second motor 226, a third motor 227 and a fourth motor 228, respectively, and the 4 servo amplifiers are a first servo amplifier 221 (connected to the first motor 225), a second servo amplifier 222 (connected to the second motor 226), a third servo amplifier 223 (connected to the third motor 227) and a fourth servo amplifier 224 (connected to the fourth motor 228), respectively. The first motor 225 is used for controlling the horizontal position of the centering stage 511, the second motor 226 is used for controlling the rotation angle of the rotating stage 512 in the horizontal direction, the third motor 227 is used for controlling the vertical position of the rotating stage 512, and the fourth motor 228 is used for controlling the horizontal position of the optical detection element 513 (i.e. adjusting the position of the identification field 311).
Preferably, the central processing Module 100 and the motion control card 210 perform information interaction through a first data transmission interface, where the first data transmission interface is mainly used for transmitting motion data and the like, and the first data transmission interface may be a VME (Versa Module Eurocard, i.e. a general computer bus) interface. The motion control card 210 controls a plurality of the servo amplifiers through a local area network (e.g., Ethernet), thereby implementing control of the system.
With reference to fig. 1, the image capturing module 300 includes, for example, an image capturing card 310, the central processing module 100 captures information in the optical detecting element 513 through the image capturing card 310, the information detected by the optical detecting element 513 includes position information and encoding information of the silicon chip 400, and most of the information detected by the optical detecting element 513 is image information. Preferably, the central processing module 100 and the image acquisition card 310 perform information interaction through a second data transmission interface (e.g., a PMC interface). The second data transmission interface is mainly used for transmitting image data, and the image capture card 310 controls the optical detection element 513 via an image transmission network (e.g., Cameralink).
The embodiment further provides a lithographic apparatus, including the above pre-alignment system, where the pre-alignment system specifically includes: a central processing module 100, a motion control module 200, a pre-alignment module 500, and an image acquisition module 300; the pre-alignment module 500 is configured to detect position information and coding information of the silicon wafer 400, and the image acquisition module 300 is configured to acquire the position information of the silicon wafer 400 and the coding information of the silicon wafer 400 and return the acquired position information and coding information to the central processing module 100; the central processing module 100 is configured to issue a motion instruction according to the position information of the silicon wafer 400, and the motion control module 200 controls the pre-alignment module 500 to move according to the motion instruction to pre-align the silicon wafer 400; the central processing module 100 is further configured to perform code identification on the silicon chip 400 according to the code information of the silicon chip 400.
Fig. 6 is a schematic flow chart of the pre-alignment method provided in the embodiment of the present invention, and as shown in fig. 6, the pre-alignment method mainly includes the following steps:
the pre-alignment module 500 detects the position information and the coding information of the silicon wafer 400, and the image acquisition module 300 acquires the position information of the silicon wafer 400 and the coding information of the silicon wafer 400 and transmits the position information and the coding information back to the central processing module 100; the central processing module 100 sends a motion instruction according to the position information of the silicon wafer 400, and the motion control module 200 controls the pre-alignment module 500 to move according to the motion instruction so as to pre-align the silicon wafer 400; and the central processing module 100 performs the code identification of the silicon chip 400 according to the code information of the silicon chip 400. Further, the pre-alignment step of the silicon wafer 400 includes achieving the centering of the silicon wafer 400 and achieving the orientation of the silicon wafer 400.
FIG. 3 is a schematic diagram of silicon chip coded image acquisition according to an embodiment of the present invention; FIG. 4 is a schematic diagram of a silicon chip notch and a local edge image according to an embodiment of the present invention. With reference to fig. 3 and 4, the centering of the silicon wafer 400 includes the following steps:
s11: obtaining a silicon wafer 400 on a turntable 512 in the pre-alignment module 500;
s12: adjusting the optical detecting element 513 in the pre-alignment module 500 to be in a linear array mode, and the central processing module 100 controlling the motion control module 200 to rotate the rotating table 512 of the pre-alignment module 500 for one circle on the silicon wafer 400, detecting the position information of the silicon wafer 400, and transmitting the position information back to the central processing module 100;
s13: the central processing module 100 calculates the position of the center of the circle of the silicon wafer 400 according to the position information;
s14: the central processing module 100 sends a motion command according to the position of the center of the circle, and the motion control module 200 controls the rotation stage 512 and the centering stage 511 in the pre-alignment module 500 to move according to the motion command, so as to achieve the centering of the silicon wafer 400.
With reference to fig. 3 and 4, the implementation of the orientation of the silicon wafer 400 includes the following steps:
s21: the central processing module 100 calculates the lowest position coordinate of the silicon chip notch 314 according to the position information, as shown in fig. 4;
s22: the central processing module 100 sends a motion instruction according to the information of the lowest position coordinate of the silicon wafer notch 314, and the motion control module 200 controls the rotation stage 512 to move according to the motion instruction, so as to rotate the lowest position of the silicon wafer notch 314 into the identification view field 311 of the optical detection element 513 and perform fine sampling;
s23: the central processing module 100 performs positioning algorithm processing on the data obtained by fine sampling to obtain a central angle of the silicon chip notch 314;
s24: the central processing module 100 sends a motion command according to the center angle information of the silicon chip notch 314, and the motion control module 200 controls the rotation stage 512 to rotate according to the motion command, so as to realize the orientation of the silicon chip 400.
The method for specifically realizing the orientation of the silicon wafer 400 comprises the following steps: firstly, according to the sampled data, the position coordinate of the lowest point of the silicon chip gap 314 is obtained by adopting a step fall method; then, rotating the silicon chip notch 314 to the vicinity of the optical detection element 513, and performing edge fine sampling on the silicon chip notch 314 to obtain fine sampling data; secondly, according to the fine sampling data, taking the position coordinate of the lowest point of the silicon chip notch 314 as an initial estimation value, then taking a plurality of sampling points in the silicon chip notch 314 by taking the initial estimation value as the center, respectively, and solving the circle center coordinate of the circular arc corresponding to the silicon chip notch 314 by adopting a matrix fitting method, wherein the intersection point of the connecting line of the circle center and the rotation center of the circular arc and the edge of the silicon chip 400 is defined as the center of the silicon chip notch 314; then, the silicon wafer notch 314 is rotated by a designated angle from the center thereof, thereby completing the positioning of the silicon wafer notch 314, and thus the orientation of the silicon wafer 400 can be completed.
Referring to fig. 3 and 4, the code for identifying the silicon chip 400 includes the following steps:
s31: the optical detection element 513 in the pre-alignment module 500 is adjusted to be in an area array mode, and the central processing module 100 controls the motion control module 200 to move the optical detection element 513 to an identification position;
s32: the image acquisition module 300 searches for a start angle and an end angle of the silicon chip code by rotating the silicon chip 400 by the motion control module 200;
as shown in fig. 3, it is assumed that the positions where the silicon chip codes are arranged on the silicon chip 400 include a first position 413 and a second position 414; the first positions 413 are axisymmetrically arranged with the center line of the silicon chip notch 314 as an axis, and the second positions 414 are axisymmetrically arranged with the radius of the silicon chip 400 with an included angle of 45 degrees with the center line of the silicon chip notch 314 as an axis. Generally, the silicon chip codes are 12 or 18 characters, each character is about 1.624 +/-0.025 in height and about 0.812 +/-0.025 in width, the maximum circular arc (circular arc formed by virtual connection of outer contour of the code) occupied by the silicon chip codes is recorded as a first circular arc 411, and the minimum circular arc (circular arc formed by virtual connection of inner contour of the code) occupied by the silicon chip codes is recorded as a second circular arc 412; through calculation, the difference between the radius lengths of the first arc 411 and the second arc 412 is 3.81mm, and the maximum angle occupied by the first position 413 and the second position 414 is 62.13 °, which is the identification angle 312, so that the total area of the silicon chip 400 occupied by the silicon chip code can be calculated, and preparation is made for subsequently acquiring the code information of the silicon chip 400.
Then, the central processing module 100 determines the position of the center line of the silicon chip notch 314, and rotates the minimum angle to make the recognition field 311 of the optical detection element 513 be located within the range from the start angle to the end angle of the silicon chip code. Fig. 7 is a schematic diagram of finding a silicon chip code image according to an embodiment of the present invention, as shown in fig. 7, a straight line where the identification view field 311 and the center of the silicon chip 400 are located is located on a radius, a radius having an included angle of 180 ° with the radius is taken as a reference line, an included angle between the radius passing through the center of the silicon chip notch 314 and the reference line is defined as θ, and when 0 ° < θ -22.5 ° < 180 °, the silicon chip code can be rotated counterclockwise by 165 ° to 180 °, and the silicon chip code can be rotated into the identification view field 311; when the angle is 180 degrees < theta-22.5 degrees <360 degrees, the silicon chip codes can be rotated clockwise to 225 degrees to 240 degrees, and then the silicon chip codes can be rotated into the identification view field 311, so that the starting angle and the ending angle of the silicon chip codes can be quickly searched.
S33: the motion control module 200 rotates the silicon wafer 400 back and forth, the image acquisition module 300 acquires an image and transmits the image back to the central processing module 100 when the silicon wafer 400 rotates back and forth, and the rotation range is about from the start angle to the end angle, that is, the rotation range can be 55 to 70 degrees, so that all codes can be acquired.
S34: the central processing module 100 processes the acquired image to obtain the coding information of the silicon wafer 400.
In S34, the central processing module 100 processes the acquired silicon chip coded image, and mainly includes the following steps: fig. 5 is a schematic diagram of a silicon chip coded image according to an embodiment of the present invention. As shown in fig. 5, firstly, performing boundary extraction on the original image of the silicon chip code, where the extracted image is a process image; performing AND operation on the process image and the image original image to obtain a result image, wherein pixel values except for the character area in the result image are zero; then, the result graph is divided into single character result graphs by a character division window 313, and then the single character result graphs are evenly divided into 12 equal parts or 18 equal parts by taking the circle center as a divergent point, so that the single character result graphs are obtained; and then, matching the single character result graph with the template of the image original graph, and splicing the single character result graph after the matching is successful, thereby obtaining the coding information of the silicon chip 400.
In summary, in the pre-alignment system, the pre-alignment method and the lithographic apparatus provided by the present invention, the pre-alignment module is used to detect the position information and the code information of the silicon wafer, and the image acquisition module acquires the position information and the code information of the silicon wafer and transmits the position information and the code information to the central processing module; the central processing module sends a motion instruction to the motion control module according to the position information of the silicon wafer, the motion control module can control the pre-alignment module to move according to the motion instruction so as to pre-align the silicon wafer, and the central processing module can also perform code identification (namely identify the ID of the silicon wafer) of the silicon wafer according to the code information of the silicon wafer. The central processing module controls the realization of the pre-alignment and the code recognition of the silicon chip without coordination of other equipment, thereby saving the time of the pre-alignment and the code recognition of the silicon chip, ensuring that a pre-alignment system has stronger functionality, not needing to additionally increase equipment (such as a bar code reader) for the code recognition of the silicon chip in the subsequent production process, reducing the cost of the equipment and being beneficial to solving the space occupation of the equipment.
The foregoing embodiments are merely illustrative of the principles of the invention and its efficacy, and are not to be construed as limiting the invention. Those skilled in the art can make various changes, substitutions and alterations to the disclosed embodiments and technical contents without departing from the spirit and scope of the present invention.
Claims (20)
1. A pre-alignment system, comprising: the device comprises a central processing module, a motion control module and a pre-alignment module; the pre-alignment module is used for detecting position information and coding information of the silicon chip; the central processing module is used for sending a motion instruction according to the position information of the silicon wafer, the motion control module is used for controlling the pre-alignment module to move according to the motion instruction, and the pre-alignment module is also used for moving under the control of the motion control module so as to pre-align the silicon wafer; the central processing module is also used for carrying out coding identification on the silicon wafer according to the coding information of the silicon wafer;
the pre-alignment module comprises an image acquisition module, and the image acquisition module is used for searching a starting angle and an ending angle of a code of the silicon chip when the silicon chip is rotated under the motion control module;
the motion control module controls the silicon wafer to rotate back and forth according to the starting angle and the ending angle;
the image acquisition module is also used for acquiring images when the silicon wafer rotates back and forth and transmitting the images to the central processing module, and the central processing module is also used for processing the acquired images so as to acquire the coding information of the silicon wafer.
2. The pre-alignment system of claim 1, wherein the pre-alignment module comprises: a rotating table, a centering table and an optical detection element;
the rotating platform is used for adjusting the angle of the silicon wafer and the vertical position of the silicon wafer, and the silicon wafer can be allowed to be handed over between the rotating platform and the centering platform through the adjustment of the vertical position of the silicon wafer;
the centering table is used for adjusting the horizontal position of the silicon wafer;
the optical detection element is used for detecting the position information of the silicon chip and the coding information of the chip.
3. The pre-alignment system of claim 2, wherein the motion control module comprises: the system comprises a motion control card, a plurality of motors and a plurality of servo amplifiers equipped for the motors;
the central processing module controls the plurality of servo amplifiers through the motion control card so as to control the plurality of motors.
4. The prealignment system of claim 3, wherein the plurality of motors includes a first motor, a second motor, a third motor, and a fourth motor, and the plurality of servo amplifiers includes a first servo amplifier connected to the first motor, a second servo amplifier connected to the second motor, a third servo amplifier connected to the third motor, and a fourth servo amplifier connected to the fourth motor;
the first motor is used for controlling the horizontal position of the centering table; the second motor is used for controlling the horizontal rotation angle of the rotating platform; the third motor is used for controlling the vertical position of the rotating platform; the fourth motor is used for controlling the horizontal position of the optical detection element.
5. The prealignment system of claim 3, wherein said central processing module and said motion control card interact via a first data transfer interface, said motion control card controlling a plurality of said servo amplifiers via a local area network.
6. The pre-alignment system as claimed in claim 2, wherein the image capturing module is configured to capture information detected by the optical detecting elements and transmit the information to the central processing module.
7. The prealignment system of claim 6, wherein the image acquisition module comprises an image acquisition card.
8. The pre-alignment system of claim 6, wherein the central processing module and the image capturing module interact via a second data transmission interface, and the image capturing module controls the optical detecting element via an image transmission network.
9. The pre-alignment system of claim 2, wherein the optical detection element is a line-to-plane switching optical detection element.
10. The prealignment system of claim 9, wherein the optical detection element comprises a charge coupled device.
11. The pre-alignment system of claim 1, wherein the central processing module comprises a central processor.
12. A lithographic apparatus comprising a pre-alignment system as claimed in any one of claims 1 to 11.
13. A method of pre-alignment, comprising the steps of:
the pre-alignment module detects position information and coding information of the silicon chip;
the central processing module sends a movement instruction according to the position information of the silicon wafer, and the movement control module controls the pre-alignment module to move according to the movement instruction so as to pre-align the silicon wafer; and
the central processing module carries out coding identification on the silicon chip according to the coding information of the silicon chip;
the code for identifying the silicon chip comprises the following steps:
s32: an image acquisition module in the pre-alignment module searches for a starting angle and an ending angle of the code of the silicon chip when the silicon chip is rotated under the control of the motion control module;
s33: the motion control module controls the silicon wafer to rotate back and forth, the image acquisition module acquires images and transmits the images to the central processing module when the silicon wafer rotates back and forth, and the rotation range is from the starting angle to the ending angle; and
s34: and the central processing module processes the acquired image to acquire the coding information of the silicon chip.
14. The pre-alignment method of claim 13, wherein the pre-aligning of the silicon wafer comprises achieving centering of the silicon wafer and achieving orientation of the silicon wafer.
15. The pre-alignment method of claim 14, wherein the centering of the silicon wafer is achieved by the steps of:
s11: placing the silicon wafer on a rotating table in the pre-alignment module;
s12: adjusting an optical detection element in the pre-alignment module to be in a linear array mode, and detecting the position information of the silicon wafer;
s13: the central processing module calculates the circle center position of the silicon wafer according to the position information of the silicon wafer; and
s14: the central processing module sends a first motion instruction according to the position of the circle center of the silicon wafer, and the motion control module controls the rotation table and the centering table in the pre-alignment module to move according to the first motion instruction so as to realize the centering of the silicon wafer.
16. The pre-alignment method of claim 15, wherein implementing the orientation of the silicon wafer comprises the steps of:
s21: the central processing module calculates the lowest position coordinate of the silicon chip gap according to the position information of the silicon chip;
s22: the central processing module sends out a second motion instruction according to the information of the lowest position coordinate of the silicon chip notch, and the motion control module controls the rotary table to move according to the second motion instruction, rotates the lowest position of the silicon chip notch into the identification field of the optical detection element and performs sampling;
s23: the central processing module is used for positioning the sampling data to obtain the central angle of the silicon chip notch; and
s24: the central processing module sends a third motion instruction according to the center angle information of the silicon chip gap, and the motion control module controls the rotation of the rotating platform according to the third motion instruction so as to realize the orientation of the silicon chip.
17. The pre-alignment method of claim 16, wherein identifying the code for the silicon slice further comprises, prior to finding the starting angle and the ending angle of the code for the silicon slice, the steps of:
s31: and adjusting the optical detection element in the pre-alignment module into an area array mode, and controlling the motion control module to move the optical detection element to an identification position by the central processing module.
18. The pre-alignment method of claim 17,
the positions of the silicon chip on which the silicon chip codes are arranged comprise a first position and a second position;
the first position takes the central line of the silicon chip gap as an axis and is arranged in an axisymmetric manner;
the second position takes the silicon wafer radius with an included angle of 45 degrees with the center line of the silicon wafer gap as an axis and is arranged in an axisymmetric manner.
19. The pre-alignment method of claim 18, further comprising, before the step S32, the steps of:
and the central processing module judges the position of the central line of the notch of the silicon chip and rotates the minimum angle to enable the identification view field of the optical detection element to be positioned in the range from the starting angle to the ending angle of the silicon chip code.
20. The pre-alignment method as claimed in claim 17, wherein in step S34, the central processing module processes the acquired silicon chip-coded image, and mainly comprises the following steps:
performing boundary extraction on the original image coded by the silicon chip to obtain a process image;
carrying out AND operation on the process image and the image original image to obtain a result image;
segmenting the result graph to obtain a single character result graph;
matching the single character result image with a template of the image original image; and
and splicing the single character result graphs after the matching is successful, thereby obtaining the coding information of the silicon chip.
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| CN201811642976.3A CN111381451B (en) | 2018-12-29 | 2018-12-29 | Pre-alignment system, pre-alignment method and photoetching equipment |
| TW108148205A TWI731534B (en) | 2018-12-29 | 2019-12-27 | Pre-alignment system, pre-alignment method and photoetching equipment |
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| CN104111595B (en) * | 2013-04-16 | 2016-08-24 | 上海微电子装备有限公司 | Pre-alignment method for the prealignment device of lithographic equipment |
| CN105632971B (en) * | 2014-11-26 | 2019-06-25 | 上海微电子装备（集团）股份有限公司 | A kind of silicon wafer processing unit and method |
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| JPH1167633A (en) * | 1997-08-18 | 1999-03-09 | Nec Yamagata Ltd | Device and method for reduction projection aligner |
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| CN111381451A (en) | 2020-07-07 |
| TWI731534B (en) | 2021-06-21 |
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