CN116540501A - Alignment method of laser imaging exposure machine - Google Patents

Alignment method of laser imaging exposure machine Download PDF

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Publication number
CN116540501A
CN116540501A CN202310498450.7A CN202310498450A CN116540501A CN 116540501 A CN116540501 A CN 116540501A CN 202310498450 A CN202310498450 A CN 202310498450A CN 116540501 A CN116540501 A CN 116540501A
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China
Prior art keywords
camera
exposure
coordinates
substrate
matching
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CN202310498450.7A
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Chinese (zh)
Inventor
郑超
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Hefei Xinqi Microelectronics Equipment Co ltd
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Hefei Xinqi Microelectronics Equipment Co ltd
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Priority to CN202310498450.7A priority Critical patent/CN116540501A/en
Publication of CN116540501A publication Critical patent/CN116540501A/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
    • 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
    • G03F7/20—Exposure; Apparatus therefor
    • 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
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2051—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source
    • G03F7/2053—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source using a laser
    • 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
    • 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
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70491—Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
    • G03F7/70516—Calibration of components of the microlithographic apparatus, e.g. light sources, addressable masks or detectors
    • 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
    • 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
    • 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
    • G03F9/7088—Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

The invention discloses a contraposition method of a laser imaging exposure machine, the exposure machine comprises: an exposure stage, a front camera and a back camera, the back camera being mounted to the exposure stage, the exposure stage being adapted to place a substrate, the front camera and the back camera being located on opposite sides of the substrate, respectively, the method comprising: establishing a coordinate system mapping relation among the back camera, the front camera and the exposure table; placing the substrate at a first exposure position and exposing the first surface, and collecting a texture image of the second surface of the substrate at the exposure position by a back camera; placing the substrate at a second surface exposure position, and acquiring a texture image of the second surface of the substrate by a front camera; establishing a mapping relation between coordinates of a substrate second surface texture image acquired by a back camera and a front camera; and obtaining the exposure position of the second surface according to the mapping relation between the texture image acquired by the back side camera and the coordinates of the texture image acquired by the front side camera. The alignment method of the laser imaging exposure machine provided by the embodiment of the invention has the advantages of accurate alignment, high reliability and the like.

Description

Alignment method of laser imaging exposure machine
Technical Field
The invention relates to the technical field of exposure machines, in particular to a contraposition method of a laser imaging exposure machine.
Background
The substrate of LDI exposure machine in the related art is smeared with exposure material, and the exposure material of the substrate is utilized to expose the pattern, and the industrial camera is used for identification and alignment, but the different substrate smears the exposure material, the exposed pattern has poor visibility, the problem of low identification degree of the industrial camera exists, and the exposure pattern of the exposure machine is different, and the exposure pattern and the exposure target have overlapping condition, thereby seriously affecting alignment and later development of the substrate.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one purpose of the invention is to provide a contraposition method of a laser imaging exposure machine, which reduces the dependence of exposure targets on photosensitive materials and has the advantages of accurate contraposition, high reliability and the like.
In order to achieve the above object, according to an embodiment of the present invention, a method for aligning a laser imaging exposure machine is used for an exposure machine, and the exposure machine includes: an exposure stage, a front side camera and a back side camera, the back side camera mounted to the exposure stage, the exposure stage adapted to place a substrate, the front side camera and the back side camera being located on opposite sides of the substrate, respectively, the method comprising: establishing a coordinate system mapping relation among the back camera, the front camera and the exposure table; placing the substrate at a first exposure position and exposing a first surface, and collecting a texture image of a second surface of the substrate at the exposure position by the back side camera; placing the substrate at a second surface exposure position, and acquiring a texture image of the second surface of the substrate by the front camera; establishing a mapping relation between coordinates of a texture image of a second surface of the substrate acquired by the back camera and the front camera; and obtaining the exposure position of the second surface of the substrate according to the mapping relation between the coordinates of the texture image acquired by the back camera and the texture image acquired by the front camera.
According to the alignment method of the laser imaging exposure machine, disclosed by the embodiment of the invention, the dependence of an exposure target on a photosensitive material is reduced, and the alignment method has the advantages of accuracy in alignment, high reliability and the like.
According to some embodiments of the invention, when the coordinate system mapping relationship between the back side camera and the front side camera is established, the coordinates of the front side camera are coincident with the coordinate system of the exposure stage surface, the front side camera is movable relative to the exposure stage, and the back side camera is fixed on the exposure stage.
According to some embodiments of the invention, the establishing a coordinate system mapping relationship between the back side camera and the front side camera includes: establishing coordinates of the back side camera and the exposure stage surfaceFirst transformation model A of coordinates 1 The method comprises the steps of carrying out a first treatment on the surface of the The texture image acquired by the back camera passes through the first transformation model A 1 And obtaining the corresponding table top coordinates of the exposure table.
Further, a target is arranged between the front camera and the second camera, and a first transformation model A is established 1 Comprising the following steps: the back camera acquires target second characteristic point coordinates S 1 The front camera acquires the coordinates S of the first characteristic point of the target 2 The method comprises the steps of carrying out a first treatment on the surface of the Converting the first characteristic point coordinates into table top coordinatesCoordinate transformation formula using target->Calculating the first transformation model parameters to build the first transformation model A 1 。
Further, a glass sheet is mounted above the back camera, and the target is formed on the glass sheet.
According to some embodiments of the invention, the mapping relation between the coordinates of the texture image of the back surface of the substrate collected by the back surface camera and the texture image collected by the front surface camera is established, including: matching texture images of the second face acquired by the front camera and the back camera through a matching algorithm; establishing a second transformation model A of coordinates of the texture image acquired by the back side camera and the texture image acquired by the front side camera 2 。
According to some embodiments of the invention, before matching the texture image acquired by the front camera with the texture image acquired by the back camera, the method further comprises:
screening coordinates of matching points of texture images acquired by the front camera and the back camera,
a. setting a difference threshold value parameter JE of the front texture and the back texture;
b. acquiring texture matching point set X of back camera 1 {1,2. Once again, the number n, acquiring texture matching points of front camera to be set as a set X 2 {1，2......n}；
c. Matching set X 1 {1,2. Of n' a plurality of first matching points C 1 And set X 2 {1,2. Of n' a plurality of second matching points C 2 ，
d. The second matching point C 2 By a first transformation model A 1 Obtaining the corresponding table top coordinates of the exposure table
e. Calculate each first matching point C 1 And a corresponding second matching point C 2 Is a difference value of (2)
f. Screening out a first matching point C of which the difference value diff is smaller than or equal to the difference threshold value parameter JE 1 And a corresponding second matching point C 2 。
Further, a second transformation model A of coordinates of texture images acquired by the back camera and the front camera is established 2 Comprising the following steps:
coordinate transformation formula using first matching pointCalculate each pair of first matching points C 1 And a corresponding second matching point C 2 Is>
Selecting a transformation model with the largest repetition number as a second transformation model A of coordinates of texture images acquired by the back camera and the front camera 2 。
According to some embodiments of the present invention, a second transformation model A of coordinates of the texture image captured by the back side camera and the texture image captured by the front side camera is constructed 2 Front;
judging whether the first matching point and the second matching point are successfully matched through a matching algorithm;
if so, establishing a mapping relation between coordinates of a substrate back texture image acquired by the back camera and a texture image acquired by the front camera;
if not, the coordinates of the matching points of the texture images acquired by the front camera and the back camera are screened again.
According to some embodiments of the invention, the coordinate points of the back exposure pattern of the substrate are matched by the coordinate points of the exposure pattern of the front surface of the substrate through the second transformation model A 2 Synchronous rotation, translation and scaling alignment.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of a laser imaging exposure machine according to an embodiment of the present invention;
FIG. 2 is a schematic view of an exposure station, a back side camera, and a glass sheet of a laser imaging exposure machine according to an embodiment of the invention;
FIG. 3 is a flow chart of a first side exposure of a registration method of a laser imaging exposure machine according to an embodiment of the invention;
FIG. 4 is a flow chart of a second side exposure of a registration method of a laser imaging exposure machine according to an embodiment of the invention;
fig. 5 is a schematic texture view of a substrate according to an embodiment of the present invention.
Description of the drawings:
an exposure machine 1, an exposure stage 100, a front camera 200, a back camera 300, and a glass sheet 400.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
The following describes a method for aligning a laser imaging exposure machine according to an embodiment of the present invention with reference to the drawings.
As shown in fig. 1 to 5, a method for aligning a laser imaging exposure machine according to an embodiment of the present invention is used for an exposure machine 1, where the exposure machine 1 includes: an exposure stage 100, a front side camera 200, and a back side camera 300, the back side camera 300 being mounted to the exposure stage 100, the exposure stage 100 being adapted to place a substrate, the front side camera 200 and the back side camera 300 being located on opposite sides of the substrate, respectively, the method comprising:
establishing a coordinate system mapping relation among the back camera, the front camera and the exposure table;
placing the substrate at a first exposure position and exposing the first surface, and collecting a texture image of the second surface of the substrate at the exposure position by a back camera;
placing the substrate at a second surface exposure position, and acquiring a texture image of the second surface of the substrate by a front camera;
establishing a mapping relation between coordinates of a substrate second surface texture image acquired by a back camera and a front camera;
and obtaining the exposure position of the second surface of the substrate according to the mapping relation between the texture image acquired by the back camera and the coordinates of the texture image acquired by the front camera.
For example, the upper surface of the exposure stage is configured with mounting holes, the mounting holes are provided with a back side camera, the back side camera is positioned on the back side of the substrate, and the front side camera faces the first surface of the substrate. The texture image on the back of the substrate is determined by the material of the substrate itself, and is irrelevant to exposure or not. The exposure process is divided into front exposure and back exposure of the substrate, wherein the exposure head is positioned above the exposure table, the first surface of the substrate is exposed first, after the first surface of the substrate is exposed, the substrate is turned over to enable the back surface of the substrate to face the exposure head above the exposure table, and then the back surface of the substrate is exposed. The first surface exposure and the second surface exposure of the substrate are aligned by the alignment method of the laser imaging exposure machine, so that alignment of the first surface exposure image and the second surface exposure image of the substrate is ensured.
According to the alignment method of the laser imaging exposure machine, firstly, the coordinate mapping relation among the back side camera, the front side camera and the exposure platform is established, and the coordinate conversion of the back side camera is consistent with the coordinate systems of the front side camera and the exposure platform, so that the back side camera can be converted into the table top coordinates identical with the front side camera. The method comprises the steps that a back camera collects texture images of the back side of a substrate at the same time of first exposure, the back camera is turned over after collecting the texture images of the back side, then the front camera of the substrate is turned over to collect the texture images of the back side, an image processing algorithm extracts texture features of the back side surface of the substrate, then the image processing algorithm is used for texture matching, texture feature point detection and matching of the substrate are carried out, and therefore an exposure pattern of the first side of the substrate and an exposure pattern of the back side of the substrate are aligned. According to the alignment method of the laser imaging exposure machine, compared with a traditional inner layer alignment mode, the alignment is not needed by a self-exposure target, so that the dependence of the exposure target on photosensitive materials is reduced, meanwhile, a self-exposure target pattern is not needed, interference with an exposure substrate pattern is avoided, and the reliability is higher.
Therefore, according to the alignment method of the laser imaging exposure machine, disclosed by the embodiment of the invention, the dependence of an exposure target on a photosensitive material is reduced, and the alignment method has the advantages of accuracy in alignment, high reliability and the like.
In some embodiments of the present invention, when a coordinate system mapping relationship between the back side camera and the front side camera is established, coordinates of the front side camera coincide with a coordinate system of a table surface of the exposure table, the front side camera is movable relative to the exposure table, and the back side camera is fixed to the exposure table.
Because the front camera motion coordinate system is coincident with the table top coordinate system, a mapping relation between the front camera coordinate system and the table top coordinate system can be established, and the coordinates of the front camera when moving on the table top can be changed into the table top coordinates. The back face camera is fixed with the exposure table and the light source, the back face camera can be multiple, the back face camera can be installed according to the requirement, and the optimal focal plane of the back face camera is adjusted to the table top of the exposure table.
In some embodiments of the present invention, as shown in fig. 3, establishing a coordinate system mapping relationship between a back side camera and a front side camera includes:
establishing a first transformation model A of the coordinates of the back camera and the coordinates of the exposure stage surface 1 ；
Texture image acquired by the back camera passes through a first transformation model A 1 And obtaining the corresponding table top coordinates of the exposure table.
Therefore, a mapping relation between the back camera coordinate system and the table top coordinate system is established, and the coordinates of the back camera when moving on the table top can be converted into table top coordinates, so that the position of the back camera is calibrated.
Further, a target is arranged between the front camera and the second camera, and a first transformation model A is established 1 Comprising the following steps: the back camera acquires target second characteristic point coordinates S 1 The front camera acquires the coordinates S of the first characteristic point of the target 2 The method comprises the steps of carrying out a first treatment on the surface of the Converting the first feature point coordinates into mesa coordinatesCoordinate transformation formula using target->Calculating first transformation model parameters to build a first transformation model A 1 。
For example, after a certain exposure time, the first transformation model A can be utilized at any time 1 Calibrating, namely ensuring that coordinates of the front camera and the back camera are kept corresponding at all times, converting the coordinates of the back camera moving to all positions into table coordinates, simultaneously acquiring the coordinates of a target center point through the back camera and the front camera, establishing a mapping relation of coordinate systems of the back camera and the front camera, and calculating to obtain a first transformation model A 1 Since the front camera is overlapped with the table top coordinate system, the coordinates of the back camera pass through the first transformation model A 1 After conversion, the coordinates can be converted into table coordinates, so that the calibration of the back camera is completed.
Further, as shown in fig. 2, a glass sheet 400 is mounted above the back camera, and targets are formed on the glass sheet 400. For example, the glass sheet 400 is configured with a circular target, and the back camera and the front camera simultaneously acquire coordinates of a center point of the target of the glass sheet 400, forming a coordinate system mapping relationship between the back camera and the front camera.
In some embodiments of the present invention, as shown in fig. 4, establishing a mapping relationship between coordinates of a second surface texture image of a substrate acquired by a back side camera and a front side camera includes:
matching texture images of the second surface acquired by the front camera and the back camera through a matching algorithm;
establishing a second transformation model A of coordinates of texture images acquired by the back camera and the front camera 2 。
After the back camera collects the texture image of the second surface substrate, the texture image is obtained by the first transformation model A 1 The position of the back camera is calibrated, so that the approximate position of the texture image collected by the second surface of the substrate can be calculated, the front camera is moved to the corresponding position to collect the texture image, the front camera and the back camera obtain two identical texture images, then the characteristics of the texture images of the first surface and the second surface are respectively extracted, then the texture characteristics are matched, the coordinates of the texture image collected by the back camera are converted into the coordinates of the table surface of the exposure table, thus obtaining the position relation of the two images with identical textures, and obtaining a second transformation model A 2 Using a second transformation model A 2 The first surface and the second surface of the substrate are aligned, an exposure target is not needed, and the exposure patterns of the first surface and the second surface of the substrate cannot be interfered.
Further, referring to fig. 4, before matching the texture image collected by the front camera with the texture image collected by the back camera, coordinates of matching points of the texture images collected by the front camera and the back camera are screened, and a first matching point C matched by the front camera is screened 1 Second matching point C matching with back camera 2 Matching the first matching point C by using the screened front camera 1 Coordinate of (C) and back camera second matching point C 2 Is used for establishing a second transformation model A 2 。
The matching algorithm is utilized to screen out a plurality of matching points of the front camera and the back camera so as to matchFirst matching point C of feature angular point coordinates 1 And a second matching point C 2 Specifically, the local curvature of the image is calculated by using a hessian matrix, and pixel points meeting the conditions are screened out as texture feature points by setting parameters of the matrix so as to obtain a first matching point C 1 And a second matching point C 2 Extracting matched pixel points, and extracting first matching points C which are matched pairwise by using a fast nearest neighbor algorithm through Hamming distance and characteristic point gradient direction 1 And a second matching point C 2 . It can be understood that the more the texture of the region texture obtained with larger pixel value variation is more obvious, the first matching point C of every two matching is extracted at the obvious position of the texture 1 And a second matching point C 2 。
Since the back camera is already calibrated with the front camera, corner coordinates C 1 And C 2 Can be converted into the corresponding coordinates of the table top, and the matched first matching point C is utilized 1 And a second matching point C 2 Establishing a second transformation model A 2 The shape of the first surface exposure pattern can be corresponding to the second surface exposure pattern, so that the second surface exposure pattern exposure shape is ensured to be relatively aligned with the shape of the first surface exposure pattern.
In some embodiments of the present invention, before matching the texture image acquired by the front camera with the texture image acquired by the back camera, the method further comprises:
screening coordinates of matching points of texture images acquired by a front camera and a back camera, wherein the screening steps are as follows:
a. setting a difference threshold value parameter JE of the front texture and the back texture;
b. acquiring texture matching point set X of back camera 1 {1,2. Once again, the number n, acquiring texture matching points of front camera to be set as a set X 2 {1，2......n}；
c. Matching set X 1 {1,2. Of n' a plurality of first matching points C 1 And set X 2 {1,2. Multiple of n }, n' a second matching point C2 of the number,
d. the second matching point C 2 By a first transformation model A 1 Obtain the corresponding table top seat of the exposure tableLabel (C)
e. Calculate each first matching point C 1 And a corresponding second matching point C 2 Is a difference value of (2)
f. Screening out a first matching point C of which the difference value diff is smaller than or equal to the difference threshold value parameter JE 1 And a corresponding second matching point C 2 。
For example, each time random is from set X 1 And X 2 Three first matching points C corresponding to each other are selected 1 And a second matching point C 2 Each time screening is performed from three first matching points C corresponding to each other 1 And a second matching point C 2 And (3) selecting matching points with the difference value diff smaller than or equal to the difference threshold parameter, and storing the points in a set. Repeating the step c and the step d for a plurality of times, thereby screening a plurality of matching points meeting the condition.
In some embodiments of the present invention, a second transformation model A of the coordinates of the texture images acquired by the back side camera and the front side camera is established 2 Comprising the following steps:
coordinate transformation formula using first matching pointCalculate each pair of first matching points C 1 And a corresponding second matching point C 2 Is>
Selecting a transformation model with the largest repetition number as a second transformation model A of coordinates of texture images acquired by the back camera and the front camera 2 。
By first using a first transformation model A 1 Second matching point C 2 Conversion to the corresponding exposure table top coordinatesThe first matching point C of the first surface is caused by the superposition of the motion coordinate system of the front camera and the coordinate system of the surface of the exposure machine 1 First matching point C of coordinates and second surface 2 The coordinates are unified as the coordinates of the exposure stage, i.e. by the first transformation model A 1 Second matching point C 2 Conversion to the corresponding exposure table top coordinates +.>Thereby, the exposure stage coordinates of the second surface texture image are obtained. A second transformation model A for selecting the transformation model with the largest repetition number as the coordinates of the texture images acquired by the back camera and the front camera 2 Ensuring a second transformation model A 2 Accuracy of (3). Texture images acquired by the front camera and the back camera of the substrate, wherein the texture images acquired by the front camera pass through a second transformation model A 2 Texture images acquired by the back camera can be obtained, and similarly, the first surface exposure pattern of the substrate passes through the second transformation model A 2 Coordinates of the pattern to be exposed of the back side camera can also be obtained. The coordinates of the exposure pattern on the second surface of the substrate can pass through the second transformation model A 2 The method ensures that the exposure patterns of the first surface and the second surface are completely aligned.
In some embodiments of the present invention, as shown in FIG. 4, a second transformation model A of the coordinates of the texture image captured by the back side camera and the texture image captured by the front side camera is constructed 2 Front;
judging whether the first matching point and the second matching point are successfully matched through a matching algorithm;
if so, establishing a mapping relation between the coordinates of the substrate back texture image acquired by the back camera and the texture image acquired by the front camera;
if not, the coordinates of the matching points of the texture images acquired by the front camera and the back camera are screened again.
If the first matching point and the second matching point are successfully matched, that is, the image processing system acquires images of the same positions of the texture images of the front camera and the back camera, a mapping relation can be established. If the first matching point and the second matching point are not successfully matched, it is possible that feature angular points of the first matching point and the second matching point are not obvious and cannot be obtained, the first matching point and the second matching point need to be screened again, and better first matching point and better second matching point are found.
In some embodiments of the present invention, the coordinate points of the back exposure pattern of the substrate are matched by passing through the second transformation model A from the coordinate points of the exposure pattern of the first surface of the substrate 2 Synchronous rotation, translation and scaling alignment.
The exposure pattern of the first surface and the exposure pattern of the second surface of the substrate are not necessarily identical, but the coordinates of the first surface and the second surface of the substrate relative to the table top of the exposure table are required to be kept identical. Through a second transformation model A 2 After that, the change of the exposure position of the first surface of the substrate passes through a second transformation model A 2 The synchronous conversion, for example, the first surface of the substrate is rotated for 90 degrees for exposure, the second surface of the substrate is synchronously converted by the second conversion model, and the synchronous conversion is also rotated for 90 degrees for exposure, so that the alignment accuracy of the exposure positions of the first surface and the second surface of the substrate is ensured.
Other configurations and operations of the alignment method of the laser imaging exposure machine according to the embodiment of the present invention are known to those skilled in the art, and will not be described in detail herein.
In the description herein, reference to the term "particular embodiment," "particular example," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. A method of aligning a laser imaging exposure machine, the method comprising: an exposure stage, a front side camera and a back side camera, the back side camera mounted to the exposure stage, the exposure stage adapted to place a substrate, the front side camera and the back side camera being located on opposite sides of the substrate, respectively, the method comprising:
establishing a coordinate system mapping relation among the back camera, the front camera and the exposure table;
placing the substrate at a first exposure position and exposing a first surface, and collecting a texture image of a second surface of the substrate at the exposure position by the back side camera;
placing the substrate at a second surface exposure position, and acquiring a texture image of the second surface of the substrate by the front camera;
establishing a mapping relation between coordinates of a texture image of a second surface of the substrate acquired by the back camera and the front camera;
and obtaining the exposure position of the second surface of the substrate according to the mapping relation between the coordinates of the texture image acquired by the back camera and the texture image acquired by the front camera.
2. The alignment method of a laser imaging exposure machine according to claim 1, wherein when the coordinate system mapping relationship between the back side camera and the front side camera is established, the coordinates of the front side camera are coincident with the coordinate system of the exposure stage surface, the front side camera is movable relative to the exposure stage, and the back side camera is fixed to the exposure stage.
3. The alignment method of the laser imaging exposure machine according to claim 2, wherein the establishing a coordinate system mapping relationship between the back side camera and the front side camera includes:
establishing a first transformation model A of the coordinates of the back camera and the coordinates of the exposure table top 1 ；
The texture image acquired by the back camera passes through the first transformation model A 1 And obtaining the corresponding table top coordinates of the exposure table.
4. The laser imaging exposure alignment method according to claim 3, wherein a target is arranged between the front camera and the second camera, and the first transformation model A is established 1 Comprising the following steps:
the back camera acquires target second characteristic point coordinates S 1 The front camera acquires the coordinates S of the first characteristic point of the target 2 ；
Converting the first characteristic point coordinates into table top coordinates
Coordinate transformation formula using targetsCalculating the first transformation model parameters to build the first transformation model A 1 。
5. The laser imaging exposure alignment method according to claim 4, wherein a glass sheet is mounted above the back side camera, and the target is formed on the glass sheet.
6. The alignment method of the laser imaging exposure machine according to claim 2, wherein the establishing a mapping relationship between coordinates of the second surface texture image of the substrate collected by the back side camera and the front side camera includes:
matching texture images of the second face acquired by the front camera and the back camera through a matching algorithm;
establishing a second transformation model A of coordinates of texture images acquired by the back camera and the front camera 2 。
7. The alignment method of the laser imaging exposure machine according to claim 6, further comprising, before matching the texture image acquired by the front side camera with the texture image acquired by the back side camera:
screening matching points of texture images acquired by the front camera and the back camera, wherein the screening step comprises the following steps:
a. setting a difference threshold value parameter JE of the front texture and the back texture;
b. acquiring texture matching point set X of back camera 1 The texture matching point of the front camera is acquired and set as a set X 2 ；
c. Matching set X 1 A plurality of first matching points C in (a) 1 And set X 2 A plurality of second matching points C in (a) 2 ，
d. The second matching point C 2 By a first transformation model A 1 Obtaining the corresponding table top coordinates of the exposure table
e. Calculate each first matching point C 1 And a corresponding second matching point C 2 Is a difference value of (2)
f. Screening out a first matching point C of which the difference value diff is smaller than or equal to the difference threshold value parameter JE 1 And a corresponding second matching point C 2 。
8. The alignment method of a laser imaging exposure machine according to claim 7, wherein a second transformation model a of coordinates of texture images acquired by the back side camera and the front side camera is established 2 Comprising the following steps:
coordinate transformation formula using the first matching pointCalculating each pair of the first matching points C 1 And the corresponding second matching point C 2 Is>
Selecting a transformation model with the largest repetition number as a second transformation model A of coordinates of texture images acquired by the back camera and the front camera 2 。
9. The alignment method of a laser imaging exposure machine according to claim 6, wherein a second transformation model a of coordinates of a texture image collected by a back side camera and a texture image collected by a front side camera is established 2 Front;
judging whether the first matching point and the second matching point are successfully matched through a matching algorithm;
if so, establishing a mapping relation between coordinates of a substrate back texture image acquired by the back camera and a texture image acquired by the front camera;
if not, the coordinates of the matching points of the texture images acquired by the front camera and the back camera are screened again.
10. The alignment method of a laser imaging exposure machine according to claim 6, wherein the coordinate points of the back exposure pattern matching the substrate pass through the second transformation model a from the coordinate points of the exposure pattern on the front surface of the substrate 2 Synchronous rotation, translation and scaling alignment.
CN202310498450.7A 2023-05-04 2023-05-04 Alignment method of laser imaging exposure machine Pending CN116540501A (en)

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