CN116203809A - Three-dimensional graph alignment system and method - Google Patents

Three-dimensional graph alignment system and method Download PDF

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Publication number
CN116203809A
CN116203809A CN202111458525.6A CN202111458525A CN116203809A CN 116203809 A CN116203809 A CN 116203809A CN 202111458525 A CN202111458525 A CN 202111458525A CN 116203809 A CN116203809 A CN 116203809A
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CN
China
Prior art keywords
wafer
ccd camera
overlay
light modulator
spatial light
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Pending
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CN202111458525.6A
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Chinese (zh)
Inventor
韩道
骆志军
姜瑾
孙文娟
吕威
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Wuhan Industrial Institute For Optoelectronics Co ltd
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Wuhan Industrial Institute For Optoelectronics Co ltd
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Priority to CN202111458525.6A priority Critical patent/CN116203809A/en
Publication of CN116203809A publication Critical patent/CN116203809A/en
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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
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • 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
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7019—Calibration
    • 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
    • G03F9/7073—Alignment marks and their environment
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)

Abstract

The invention discloses a three-dimensional pattern alignment system and a method, which relate to the technical field of laser and provide a three-dimensional pattern alignment system, wherein a wafer is arranged on a displacement table, and alignment marks and patterns for alignment detection are manufactured on the wafer; the CCD camera, the first dichroic mirror, the second dichroic mirror, the third spatial light modulator, the objective lens and the displacement table are sequentially arranged on the same linear optical path, and the first dichroic mirror and the second dichroic mirror are arranged at a preset angle and are used for respectively receiving the first light beam from the first laser unit and the second light beam from the second laser unit. The alignment detection method in the alignment detection technology is used for detecting and correcting the alignment mark precision by means of the spatial light modulator projection and the CCD camera acquisition.

Description

Three-dimensional graph alignment system and method
Technical Field
The invention relates to the technical field of laser, in particular to a three-dimensional graph alignment system and method.
Background
With the development of semiconductor technology, the size limit of the transfer pattern of the lithography technology is reduced by 2-3 orders of magnitude (from millimeter level to submicron level), and the lithography technology has been developed from the conventional optical technology to the application of new technologies such as electron beams, X-rays, micro-ion beams, lasers and the like; the wavelengths used have been extended from 4000 angstroms to the order of magnitude of 0.1 angstroms. Photolithography is a precision micromachining technique. The semiconductor device is also widely used for manufacturing semiconductor devices, various integrated circuits, flat panel displays (such as liquid crystal displays), circuit boards, biochips, micromechanical electronic chips, optoelectronic circuit chips and the like.
The photolithography process refers to a process of transferring a pattern onto the photoresist on the surface photoresist sheet through processes such as exposure and development, and is ready for the next etching or ion implantation process. The three-dimensional pattern can be realized by layer-by-layer lithography, so that more than 10 lithography processes are needed in the manufacturing process of the invar chip, and the lithography of each layer of layout needs to be aligned with the previous layer of pattern in advance.
Currently, in an alignment system, calibration of the position coordinates of a previous layer of alignment marks is realized by a CCD camera collecting picture and image processing technology. In order to avoid the influence of optical system distortion, the center of the alignment mark is coincided with the center of the CCD field of view during the calibration of the alignment mark position, and the alignment mark position can be realized by moving a precision platform. At this time, the position coordinate reading fed back by the platform is the position coordinate of the alignment mark, the position coordinate information of the alignment mark is fed back to the motion platform, and the motion control system is used for controlling the alignment exposure. The alignment precision of alignment exposure is obviously influenced by the extraction precision of alignment marks, and the extraction precision of two alignment marks is limited by the positioning precision and repeatability of a platform.
Disclosure of Invention
The invention aims to provide a three-dimensional graph alignment system and a three-dimensional graph alignment method, which are used for improving alignment accuracy of three-dimensional graphs.
In order to solve the technical problems, the invention provides a first solution: there is provided a three-dimensional pattern alignment system comprising a first laser unit for providing a first light beam, a second laser unit for providing a second light beam, a CCD camera, a first dichroic mirror, a second dichroic mirror, a third spatial light modulator, an objective lens and a displacement stage, wherein,
the displacement table is provided with a wafer, and a registration mark and an overlay detection pattern are manufactured on the wafer;
the CCD camera, the first dichroic mirror, the second dichroic mirror, the third spatial light modulator, the objective lens and the displacement table are sequentially arranged on the same linear optical path, and the first dichroic mirror and the second dichroic mirror are arranged at a preset angle and are used for respectively receiving the first light beam from the first laser unit and the second light beam from the second laser unit.
Further, the first laser unit comprises a first laser, a first lens and a first spatial light modulator which are sequentially arranged along the same straight line light path.
Further, the second laser unit comprises a second laser, a second lens and a second spatial light modulator which are sequentially arranged along the same straight line light path.
Further, the alignment marks are in a cross shape.
Further, the overlay detection pattern is two patterns with the same center point and amplified proportionally.
In order to solve the technical problems, the invention provides a second solution: the three-dimensional pattern alignment method is applied to the three-dimensional pattern alignment system, and comprises the following steps:
starting a first laser unit, controlling the displacement table to move, and acquiring images of alignment marks on the wafer in real time through a CCD camera;
detecting the coordinate of the alignment mark center of the wafer in the CCD camera in the image acquired by the CCD camera, stopping moving the displacement table when the alignment mark center is overlapped with a certain specific position coordinate in the field of view of the CCD camera, and recording the position coordinate fed back by the displacement table;
keeping the displacement table stationary, projecting an overlay pattern to the wafer through a third spatial light modulator, and collecting the overlay pattern projected to the wafer by the third spatial light modulator and a detection pattern for overlay on the wafer by a CCD camera;
comparing the overlay pattern projected by the third spatial light modulator to the wafer with the detection pattern for overlay on the wafer to obtain the center deviation of the overlay pattern projected by the third spatial light modulator to the wafer and the detection pattern for overlay on the wafer;
and according to the center deviation, adjusting the specific position coordinates in the view field of the CCD camera, starting a second laser unit, and adjusting a second dichroic mirror to realize confocal of the first light beam and the second light beam.
The alignment detection method in the alignment detection technology is used for detecting and correcting the alignment mark precision by means of the spatial light modulator projection and the CCD camera acquisition. In the invention, the overlay measurement result is the offset relation between the pattern of the spatial light modulator and the pattern on the wafer, and the offset is irrelevant to the positioning precision of the displacement table and the feedback position information. When the offset of the overlay measurement result is zero, the extraction precision error of the representative alignment mark position is zero. The positioning of the displacement table is to find the position of the alignment mark by performing image processing on the image acquired by the alignment mark, and the alignment accuracy of the three-dimensional graph can be improved by correcting the position of the alignment mark.
Drawings
FIG. 1 is a schematic view of the overall apparatus of the present invention;
FIG. 2 is a diagram of alignment marks and overlay patterns on a wafer; FIG. 3a is a schematic diagram of a spatial light modulator according to the present embodiment;
FIG. 3b is a schematic diagram of an image of a spatial light modulator pattern acquired by a CCD camera in the present embodiment;
FIG. 3c is a diagram of the spatial light modulator after the center of the alignment mark is detected;
fig. 3d is a schematic diagram of an image of the spatial light modulator after the center of the alignment mark acquired by the CCD camera is detected.
Reference numerals:
a first laser unit 100, a second laser unit 200, a CCD camera 300, a first dichroic mirror 400, a second dichroic mirror 500, a third spatial light modulator 600, an objective lens 700, a displacement stage 900, a wafer 800, a third spatial light modulator 600, a third spatial light modulator,
A first laser 101, a first lens 102, a first spatial light modulator 103;
a second laser 201, a second lens 202, a second spatial light modulator 203.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, are intended to fall within the scope of the present invention.
The invention is suitable for the alignment of the three-dimensional patterns of the double-beam laser lithography technology. Under the limitation of the optical diffraction limit principle, the resolution of the photoetching machine is proportional to the wavelength of the light source used. In order to achieve higher lithographic resolution, it is internationally common to use ultraviolet light sources to achieve nanometer resolution. At present, 365 nm light source photoetching machines are mostly adopted for manufacturing domestic optical chips, and the resolution ratio of the photoetching machines is about 180 nm. To further increase the resolution, under the limitation of the optical diffraction limit principle, an ultraviolet light source with a shorter wavelength needs to be adopted instead of a visible light source with a longer wavelength, but the difficulty and the cost of developing and developing the lithography equipment are greatly increased. The dual-beam laser lithography technology breaks through the diffraction limit of light by overlapping two beams by adopting two beams of visible light, wherein one beam of visible light is manufacturing light and the other beam of visible light is auxiliary light, so that better lithography resolution can be achieved when a longer wavelength visible light source is used than when a 365-nanometer wavelength ultraviolet light source is used.
FIG. 1 is a schematic view of the overall apparatus of the present invention. As shown in fig. 1, the three-dimensional pattern alignment system includes a first laser unit 100 for providing a first light beam, a second laser unit 200 for providing a second light beam, a CCD camera 300, a first dichroic mirror 400, a second dichroic mirror 500, a third spatial light modulator 600, an objective lens 700, and a displacement stage 900, wherein,
the displacement stage 900 is provided with a wafer 800, and the wafer 800 is provided with alignment marks and alignment detecting patterns, and the CCD camera 300, the first dichroic mirror 400, the second dichroic mirror 500, the third spatial light modulator 600, the objective lens 700, and the displacement stage 900 are sequentially disposed on the same linear optical path, and the first dichroic mirror 400 and the second dichroic mirror 500 are disposed at a predetermined angle for receiving the first light beam from the first laser unit 100 and the second light beam from the second laser unit 200, respectively.
Further, the first laser unit 100 includes a first laser 101, a first lens 102, and a first spatial light modulator 103, which are sequentially disposed along the same straight-line optical path. The first spatial light modulator 103 may be used to adjust the shape and distribution of the first light beam.
Further, the second laser unit 200 includes a second laser 201, a second lens 202, and a second spatial light modulator 203, which are sequentially disposed along the same straight optical path. The second spatial light modulator 203 may be used to adjust the shape and distribution of the second light beam.
Fig. 2 illustrates alignment marks and overlay patterns on a wafer 800, and as shown in fig. 2, the alignment marks may be in a cross shape. The overlay detection pattern may be two patterns with the same center point and scaled up, and in this embodiment, a large frame is used to overlay a small frame. In this way, the center deviation between the two frames is calculated respectively, namely the detection result is not dependent on the reading fed back by the current platform, and is not limited by some absolute errors generated in the process of extracting the center position, so that the influence of a plurality of external sensitive factors on the measurement result is eliminated.
The application also provides a three-dimensional graph alignment method which is applied to the three-dimensional graph alignment system and comprises the following steps:
step S1: the first laser unit 100 is started, the displacement table 900 is controlled to move, and images of alignment marks on the wafer 800 are acquired in real time through the CCD camera 300.
This step may be preceded by preparing a wafer 800 and selecting a particular area to prepare alignment marks and overlay detection patterns. First, the first laser unit 100 is turned on to align the first laser with the alignment mark on the wafer 800.
Step S2: and detecting the coordinates of the center of the alignment mark of the wafer 800 in the CCD camera 300 in the image acquired by the CCD camera 300, stopping moving the displacement table 900 when the center of the alignment mark is overlapped with the coordinates of a certain specific position in the field of view of the CCD camera, and recording the position coordinates fed back by the displacement table 900.
Specifically, the picture of fig. 3a is input to the spatial light modulator through a computer, and the front is half full bright and half full dark; projecting the pattern through a third spatial light modulator 600 onto a wafer 800; the reflected light of the pattern passes through the imaging system and reaches the CCD camera 300, resulting in a picture as shown in fig. 3 b.
Step S3: the displacement stage 900 is kept stationary, and the overlay pattern is projected onto the wafer 800 by the third spatial light modulator 600, and the CCD camera 300 captures the overlay pattern projected onto the wafer 800 by the third spatial light modulator 600, and the detection pattern for the overlay on the wafer 800.
Specifically, the CCD camera 300 is kept stationary, the displacement table is controlled to move, the image of the alignment mark is acquired in real time by the CCD camera 300, the computer is used for image processing to find the center position coordinate (CCD pixel coordinate) of the alignment mark, and when the position coordinate is a specific position coordinate, the position coordinate is assumed to be (X 0 ,Y 0 ) And stopping the movement of the displacement table, and recording the position coordinates (Xi, yi) fed back by the platform. Illustratively, the specific position is a center point position or a coordinate origin position of the CCD camera field of view.
Step S4: comparing the overlay pattern projected by the third spatial light modulator 600 to the wafer 800 with the detection pattern for overlay on the wafer 800 to obtain a center deviation between the overlay pattern projected by the third spatial light modulator 600 to the wafer 800 and the detection pattern for overlay on the wafer 800;
specifically, the pattern of fig. 3c is input to the spatial light modulator through computer control, the pattern is projected onto the wafer 800, the displacement table is kept motionless, the CCD camera 300 collects the reflection pattern of the wafer 800 at this time, the pattern as shown in fig. 3d is obtained, and the center deviation (Δxi, Δyi) of the projected pattern and the existing overlay pattern of the wafer 800 is measured by using an overlay analysis means.
Step S5: according to the center deviation, the specific position coordinates in the field of view of the CCD camera are adjusted, the second laser unit 200 is started, the second dichroic mirror 500 is adjusted, and confocal of the first light beam and the second light beam is achieved.
Specifically, after correcting the position of the displacement table 900 through the center deviation, the second laser unit 200 is turned on, and the second dichroic mirror 500 is adjusted, so as to implement confocal of the first beam and the second beam, so that the dual-beam laser lithography system has higher precision.
The alignment detection method in the alignment detection technology is used for detecting and correcting the alignment mark precision by the spatial light modulator mapping and the CCD camera 300 collecting pictures. In the present invention, the overlay measurement is the offset relationship between the spatial light modulator pattern and the pattern on the wafer 800, and the offset is irrelevant to the positioning accuracy of the displacement table 900 and the feedback position information. When the offset of the overlay measurement result is zero, the extraction precision error of the representative alignment mark position is zero. The positioning of the displacement table 900 is to find the position of the alignment mark by performing image processing on the image acquired by the alignment mark, and the alignment accuracy of the three-dimensional graph can be improved by correcting the position of the alignment mark.
The foregoing examples merely illustrate embodiments of the invention and are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (6)

1. A three-dimensional pattern alignment system comprising a first laser unit for providing a first light beam, a second laser unit for providing a second light beam, a CCD camera, a first dichroic mirror, a second dichroic mirror, a third spatial light modulator, an objective lens and a displacement stage, wherein,
the displacement table is provided with a wafer, and a registration mark and an overlay detection pattern are manufactured on the wafer;
the CCD camera, the first dichroic mirror, the second dichroic mirror, the third spatial light modulator, the objective lens and the displacement table are sequentially arranged on the same linear optical path, and the first dichroic mirror and the second dichroic mirror are arranged at a preset angle and are used for respectively receiving the first light beam from the first laser unit and the second light beam from the second laser unit.
2. The three-dimensional graphics alignment system of claim 1, wherein the first laser unit comprises a first laser, a first lens, and a first spatial light modulator disposed sequentially along a same straight optical path.
3. The three-dimensional pattern alignment system of claim 1, wherein said second laser unit comprises a second laser, a second lens, and a second spatial light modulator disposed sequentially along a same straight optical path.
4. A three-dimensional graphic alignment system according to any of claims 1-3, wherein the alignment marks are "cross" shaped.
5. A three-dimensional pattern alignment system according to any of claims 1-3, wherein the overlay detection pattern is two patterns with the same center point and scaled up.
6. A three-dimensional pattern alignment method applied to the three-dimensional pattern alignment system according to any one of claims 1 to 5, the three-dimensional pattern alignment method comprising:
starting a first laser unit, controlling the displacement table to move, and acquiring images of alignment marks on the wafer in real time through a CCD camera;
detecting the coordinate of the alignment mark center of the wafer in the CCD camera in the image acquired by the CCD camera, stopping moving the displacement table when the alignment mark center is overlapped with a certain specific position coordinate in the field of view of the CCD camera, and recording the position coordinate fed back by the displacement table;
keeping the displacement table stationary, projecting an overlay pattern to the wafer through a third spatial light modulator, and collecting the overlay pattern projected to the wafer by the third spatial light modulator and a detection pattern for overlay on the wafer by a CCD camera;
comparing the overlay pattern projected by the third spatial light modulator to the wafer with the detection pattern for overlay on the wafer to obtain the center deviation of the overlay pattern projected by the third spatial light modulator to the wafer and the detection pattern for overlay on the wafer;
and according to the center deviation, adjusting the specific position coordinates in the view field of the CCD camera, starting a second laser unit, and adjusting a second dichroic mirror to realize confocal of the first light beam and the second light beam.
CN202111458525.6A 2021-12-01 2021-12-01 Three-dimensional graph alignment system and method Pending CN116203809A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111458525.6A CN116203809A (en) 2021-12-01 2021-12-01 Three-dimensional graph alignment system and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111458525.6A CN116203809A (en) 2021-12-01 2021-12-01 Three-dimensional graph alignment system and method

Publications (1)

Publication Number Publication Date
CN116203809A true CN116203809A (en) 2023-06-02

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CN202111458525.6A Pending CN116203809A (en) 2021-12-01 2021-12-01 Three-dimensional graph alignment system and method

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