CN104614952A - Real-time focusing method and device based on passive focusing - Google Patents
Real-time focusing method and device based on passive focusing Download PDFInfo
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- CN104614952A CN104614952A CN201410844492.2A CN201410844492A CN104614952A CN 104614952 A CN104614952 A CN 104614952A CN 201410844492 A CN201410844492 A CN 201410844492A CN 104614952 A CN104614952 A CN 104614952A
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Abstract
The invention discloses a real-time focusing method and device based on passive focusing, and belongs to the technical field of the super-large-scale integrated circuit equipment industry. The real-time focusing method based on the passive focusing comprises the following steps: exposing according to stripes by a scanning type lithography machine, wherein all stripes form a whole exposure area; determining a real-time focusing area according to the exposure area, and dividing the real-time focusing area into to-be-fitted areas; before exposing a certain stripe, calculating focal plane values of four corners of all to-be-fitted areas which are intersected with the stripe to be exposed by utilizing the passive focusing, and fitting by utilizing matrix operations to obtain focal plane equations of the to-be-fitted areas; when exposing a certain stripe, finding a fitted area, obtaining a focal plane value by utilizing the focal plane equation of the fitted area, and moving an exposure substrate Wafer to realize precise focusing. The real-time focusing method and device based on the passive focusing have the advantages that the focusing precision and the focusing efficiency are improved; compared with pure software focusing, the real-time focusing device based on the passive focusing has a higher speed; demands on quick and real-time focusing are met; finer and quicker focusing effects are achieved; furthermore, the cost is low, and no hardware cost is increased.
Description
Technical field
The present invention relates to a kind of real-time focus method based on passive focusing and device, be mainly used in high-rate laser direct imaging Optical Coatings for Photolithography, belong to VLSI (very large scale integrated circuit) equipment industry technology field.
Background technology
High speed litho machine not only has higher requirements to the graphical quality exposed, and also has very high requirement to the production capacity of equipment.Focusing system is one of very important module in litho machine, the graphical quality that its performance not only affects exposure also direct impact exposure production capacity.
Focus on and inaccurate will cause that the figure exposed is fuzzy, distortion, finally cause chip rejection.If focusing speed can have a strong impact on exposure production capacity again too slowly, cause the decline of equipment performance.Finding a kind of focusing system efficiently in the industry always.Traditional focusing system has two kinds, a kind of is the passive focusing of pure software formula, then this kind of mode by utilizing the mode of image procossing to find most picture rich in detail to realize focusing on industrial camera continuous acquisition exposed substrate epigraph in platform Z axis motion process, and feature is that cost is low, and speed is slow; Another kind is that the active of the formula of pure hardware focuses on, and this mode utilizes stadimeter, calculates focal plane value realization focusing by measuring exposed substrate height in real time.Initiatively focusing speed is obviously improved, but expensive, and complicated structure.
Summary of the invention
For above-mentioned prior art Problems existing, the invention provides a kind of real-time focus method based on passive focusing and device, precision and efficiency is focused on by adding software algorithm to improve in the system of the passive focusing of pure software, realize focusing on speed faster than pure software, meet the demand focused in real time fast, realize meticulousr, focusing effect faster, and with low cost, any hardware cost can not be increased.
To achieve these goals, this based on the concrete steps of the real-time focus method of passive focusing is:
(A), scan-type litho machine exposes according to band, and band is a rectangle exposure area, and single pass exposes a band, the sequential exposure of band then band, and all bands form whole exposure area;
(B), according to exposure area in step (1) real-time focal zone is determined, using real-time focal zone according to certain width be highly divided into some little rectangular areas as treating fitted area;
(C), expose before a certain band by the mode of passive focusing by ribbing cross therewith need the focal plane value of four vertex positions of fitted area and calculate out, by each position (X treating fitted area four summits, Y) and focal plane value carry out matrix operation, matching obtains the focal plane equation in this region;
(D) by position (x0 that three axle locating platform Stage are current when, exposing a certain band, y0), find the fitted area comprising this position, and by (x0, y0) the focal plane equation in this region is substituted into, thus obtaining the three focal plane value f0s of axle locating platform Stage in this position, the Z axis moving dynamic triaxial locating platform Stage realizes the focusing of this position to f0 position.
Further, the passive focusing in described step (C) is as follows:
(1), the times N of platform Z axis moving step length Step and movement is altogether set;
(2), with current z-axis position Z0 for benchmark, calculate and focus on extreme lower position P0, P0=Z0 – Step*N/2; And focus on extreme higher position Pn, P1=Z0+Step*N/2;
(3), mobile z-axis to P0 position, CCD image sensor gathers the image of this position and records now platform Z axis position, calculates the sharpness C0 of this station acquisition to image by image processing algorithm;
(4), mobile z-axis to P1 position, P0+step, gathers this location drawing picture and calculates sharpness C1;
(5), repeat step (4) to Pn position, P0+step*N, gathers this location drawing picture and calculates sharpness Cn;
(6) the position Zx of the platform Z axis corresponding to the Cx that in C0 to Cn, sharpness is the highest, is found out;
(7), mobile platform Z axis to Zx position, namely realize this passive focusing.
Further, described step (C) is in exposure preparatory stage executed in parallel.
Meanwhile, present invention also offers a kind of real-time focalizer based on passive focusing, comprise by three axle locating platform Stage, and be positioned at and be fixed on the structural CCD image sensor of light path system and optical imaging lens Lens above Stage and combine and form.
Further, described three axle locating platform Stage comprise the High Precision Linear Motor of X, Y, Z tri-direction movements;
Described CCD image sensor and optical imaging lens Lens are arranged in the light path system structure that is positioned at above Stage;
The Z axis of described three axle locating platform Stage installs exposed substrate Wafer.
Compared with prior art, this real-time focus method based on passive focusing and device utilize passive the focusing on of pure software formula to treat that four summits in fitted rectangle region focus on, then utilize the focal plane equation in matrix operation fitted rectangle region, calculate focal plane value in real time by three axle locating platform Stage positions and focal plane equation during exposure thus realize supper-fast focusing; Can fitted area size be treated realize meticulousr by adjustment or focus on faster in practical application.The present invention realizes focusing on speed faster than pure software, meets the demand focused on fast in real time, realizes meticulousr, focusing effect faster, and with low cost, can not increase any hardware cost.
Accompanying drawing explanation
Fig. 1 is exposure area in the present invention, exposure band, focal zone, focusing band and treat fitted area schematic diagram;
Fig. 2 is apparatus structure schematic diagram of the present invention;
Fig. 3 is the enlarged diagram of exposed substrate Wafer in Fig. 2.
Embodiment
Below in conjunction with accompanying drawing, the present invention will be further described.
As shown in figures 1 and 3, this based on the concrete steps of the real-time focus method of passive focusing is:
(A), scan-type litho machine exposes according to band, and band is a rectangle exposure area, and single pass exposes a band, the sequential exposure of band then band, and all bands form whole exposure area;
(B), according to exposure area in step (1) real-time focal zone is determined, using real-time focal zone according to certain width be highly divided into some little rectangular areas as treating fitted area;
(C), expose before a certain band by the mode of passive focusing by ribbing cross therewith need the focal plane value of four vertex positions of fitted area and calculate out, by each position (X treating fitted area four summits, Y) and focal plane value carry out matrix operation, matching obtains the focal plane equation in this region;
(D) by position (x0 that three axle locating platform Stage are current when, exposing a certain band, y0), find the fitted area comprising this position, and by (x0, y0) the focal plane equation in this region is substituted into, thus obtaining the three focal plane value f0s of axle locating platform Stage in this position, the Z axis moving dynamic triaxial locating platform Stage realizes the focusing of this position to f0 position.
Further, as shown in Figure 2, CCD image sensor receives the light beam image from optical imaging lens Lens, and this light beam image takes from the feature pattern on exposed substrate Wafer.Passive focusing in described step (C) is as follows:
(1), the times N of platform Z axis moving step length Step and movement is altogether set;
(2), with current z-axis position Z0 for benchmark, calculate and focus on extreme lower position P0, P0=Z0 – Step*N/2; And focus on extreme higher position Pn, P1=Z0+Step*N/2;
(3), mobile z-axis to P0 position, CCD image sensor gathers the image of this position and records now platform Z axis position, calculates the sharpness C0 of this station acquisition to image by image processing algorithm;
(4), mobile z-axis to P1 position, P0+step, gathers this location drawing picture and calculates sharpness C1;
(5), repeat step (4) to Pn position, P0+step*N, gathers this location drawing picture and calculates sharpness Cn;
(6) the position Zx of the platform Z axis corresponding to the Cx that in C0 to Cn, sharpness is the highest, is found out;
(7), mobile platform Z axis to Zx position, namely realize this passive focusing.
Further, described step (C), in exposure preparatory stage executed in parallel, does not affect exposure production capacity.
Simultaneously, as shown in Figure 2, present invention also offers a kind of real-time focalizer based on passive focusing, comprise by three axle locating platform Stage, and be positioned at and be fixed on the structural CCD image sensor of light path system and optical imaging lens Lens above Stage and combine and form.
Further, described three axle locating platform Stage comprise the High Precision Linear Motor of X, Y, Z tri-direction movements;
Described CCD image sensor and optical imaging lens Lens are arranged in the light path system structure that is positioned at above Stage;
The Z axis of described three axle locating platform Stage installs exposed substrate Wafer.
In sum, by the mode of passive focusing, this real-time focus method based on passive focusing and device are treating that four summits in fitted rectangle region focus on, then utilize the focal plane equation in matrix operation fitted rectangle region, calculate focal plane value in real time by three axle locating platform Stage positions and focal plane equation during exposure thus realize supper-fast focusing; Can fitted area size be treated realize meticulousr by adjustment or focus on faster in practical application.The present invention realizes focusing on speed faster than pure software, meets the demand focused on fast in real time, realizes meticulousr, focusing effect faster, and with low cost, can not increase any hardware cost.
Claims (5)
1., based on a real-time focus method for passive focusing, it is characterized in that, concrete steps are as follows:
(A), scan-type litho machine exposes according to band, and band is a rectangle exposure area, and single pass exposes a band, the sequential exposure of band then band, and all bands form whole exposure area;
(B), according to exposure area in step (1) real-time focal zone is determined, using real-time focal zone according to certain width be highly divided into some little rectangular areas as treating fitted area;
(C), expose before a certain band by the mode of passive focusing by ribbing cross therewith need the focal plane value of four vertex positions of fitted area and calculate out, by each position (X treating fitted area four summits, Y) and focal plane value carry out matrix operation, matching obtains the focal plane equation in this region;
(D) by position (x0 that three axle locating platform Stage are current when, exposing a certain band, y0), find the fitted area comprising this position, and by (x0, y0) the focal plane equation in this region is substituted into, thus obtaining the three focal plane value f0s of axle locating platform Stage in this position, the Z axis moving dynamic triaxial locating platform Stage realizes the focusing of this position to f0 position.
2. a kind of real-time focus method based on passive focusing according to claim 1, is characterized in that,
Passive focusing in described step (C) is as follows:
(1), the times N of platform Z axis moving step length Step and movement is altogether set;
(2), with current z-axis position Z0 for benchmark, calculate and focus on extreme lower position P0, P0=Z0 – Step*N/2; And focus on extreme higher position Pn, P1=Z0+Step*N/2;
(3), mobile z-axis to P0 position, CCD image sensor gathers the image of this position and records now platform Z axis position, calculates the sharpness C0 of this station acquisition to image by image processing algorithm;
(4), mobile z-axis to P1 position, P0+step, gathers this location drawing picture and calculates sharpness C1;
(5), repeat step (4) to Pn position, P0+step*N, gathers this location drawing picture and calculates sharpness Cn;
(6) the position Zx of the platform Z axis corresponding to the Cx that in C0 to Cn, sharpness is the highest, is found out;
(7), mobile platform Z axis to Zx position, namely realize this passive focusing.
3. a kind of real-time focus method based on passive focusing according to claim 1, is characterized in that,
Described step (C) is in exposure preparatory stage executed in parallel.
4., based on a real-time focalizer for passive focusing, it is characterized in that,
Comprise by three axle locating platform Stage, and be positioned at and be fixed on the structural CCD image sensor of light path system and optical imaging lens Lens above Stage and combine and form.
5. a kind of real-time focalizer based on passive focusing according to claim 4, is characterized in that,
Described three axle locating platform Stage comprise the High Precision Linear Motor of X, Y, Z tri-direction movements;
Described CCD image sensor and optical imaging lens Lens are arranged in the light path system structure that is positioned at above Stage;
The Z axis of described three axle locating platform Stage installs exposed substrate Wafer.
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| CN201410844492.2A CN104614952A (en) | 2014-12-30 | 2014-12-30 | Real-time focusing method and device based on passive focusing |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106707695A (en) * | 2016-11-28 | 2017-05-24 | 深圳凯世光研股份有限公司 | Real-time focusing method and device based on active focusing |
| CN109239901A (en) * | 2018-11-07 | 2019-01-18 | 凌云光技术集团有限责任公司 | A kind of micro imaging system focusing plane Fast Calibration, focusing localization method and device |
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| CN101498831A (en) * | 2008-01-30 | 2009-08-05 | 冀瑜 | Auxiliary automatic focusing system and method for optical imaging system |
| CN102455247A (en) * | 2010-11-03 | 2012-05-16 | 上海微电子装备有限公司 | Device and method for detecting optimal focal plane of projection objective |
| CN104216241A (en) * | 2014-09-15 | 2014-12-17 | 江苏影速光电技术有限公司 | Real-time focusing method and device based on Keyence |
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2014
- 2014-12-30 CN CN201410844492.2A patent/CN104614952A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101498831A (en) * | 2008-01-30 | 2009-08-05 | 冀瑜 | Auxiliary automatic focusing system and method for optical imaging system |
| CN102455247A (en) * | 2010-11-03 | 2012-05-16 | 上海微电子装备有限公司 | Device and method for detecting optimal focal plane of projection objective |
| CN104216241A (en) * | 2014-09-15 | 2014-12-17 | 江苏影速光电技术有限公司 | Real-time focusing method and device based on Keyence |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106707695A (en) * | 2016-11-28 | 2017-05-24 | 深圳凯世光研股份有限公司 | Real-time focusing method and device based on active focusing |
| CN106707695B (en) * | 2016-11-28 | 2018-09-21 | 深圳凯世光研股份有限公司 | A kind of real-time focus method and device focused based on active |
| CN109239901A (en) * | 2018-11-07 | 2019-01-18 | 凌云光技术集团有限责任公司 | A kind of micro imaging system focusing plane Fast Calibration, focusing localization method and device |
| CN109239901B (en) * | 2018-11-07 | 2021-08-27 | 凌云光技术股份有限公司 | Method and device for quickly calibrating focusing surface and positioning focusing of microscopic imaging system |
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Application publication date: 20150513 |
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