CN101216684B

CN101216684B - Spherical surface photolithography system with area differentiation

Info

Publication number: CN101216684B
Application number: CN200810056381XA
Authority: CN
Inventors: 赵立新; 邢薇; 唐小萍; 胡松
Original assignee: Institute of Optics and Electronics of CAS
Current assignee: Institute of Optics and Electronics of CAS
Priority date: 2008-01-17
Filing date: 2008-01-17
Publication date: 2010-06-30
Anticipated expiration: 2028-01-17
Also published as: CN101216684A

Abstract

A spherical lithography system with area differentiation comprises a light source, an illumination system, a mask graph generator, a computer control system, a projection imaging system and an object table. The light source provides illumination light which illuminates the mask graph generator after being parallel uniformized by the illumination system; the computer control system controls the mask graph generator to provide mask graphs, and subdivides an exposure field into a plurality of units according to the curvature of a sample and the focus depth of the projection imaging system, so that the mask graph generator does not defocus on a single-binning imaging; the projection imaging system develops the mask graphs provided by the mask graph generator onto the sample mounted on the object table; and the computer control system identifies the swing length and the bidimensional movement of the object table according to the curvature of the spherical sample, and differentiates the areaof the plane mask, thereby realizing the surface splicing lithography on the samples with different curvatures. The invention has great flexibility and maneuverability in the projection exposure lith ography of the spherical samples, and has indigenous advantage in the exposure lithography of the spherical samples with different curvature radiuses.

Description

A kind of spherical surface photolithography system with area differentiation

Technical field

The present invention relates to a kind of projection exposure etching system with sphere sample, is that a kind of method of area differentiation that adopts is divided bin splicing exposure to the sphere sample, realizes the photomask surface of different curvature sample.

Technical background

Tradition projection lithography technology remains the photoetching of plane to the plane, is difficult to realize the imaging exposure of plane mask to the curved surface sample; In order once to finish the exposure photo-etching of plane mask to the curved surface sample, adopt special projection objective system, correct filed curvature, this can only be at the sample of specific curvature face shape, and is powerless for the sample of different curvature face shape; For directly writing the class photoetching at present, for example: laser, electron beam, ion beam etc. focus on direct writing technology, though as be furnished with special objective table and can satisfy the spherical surface photolithography requirement, this method belongs to point-to-point processing, working (machining) efficiency is extremely low, the cost height is not suitable for quantizing type of production and makes.

Summary of the invention

The technical matters that the present invention solves is: for overcoming above deficiency, the invention provides a kind of spherical surface photolithography system with area differentiation, utilize this device can realize the photomask surface of different curvature sample, and has simple in structure, dependable performance, sample processing to curved transition has good dirigibility, advantage of high production efficiency.

The technical solution adopted for the present invention to solve the technical problems is: a kind of spherical surface photolithography system with area differentiation, form by light source, illuminator, mask graph generator, computer control system, projection imaging system and objective table; Light source provides the illumination light of required exposure wavelength for etching system, after this illumination light is passed through illuminator parallelization and homogenising, illumination mask graph generator, provide mask graph by computer control system control mask graph generator, the simultaneous computer control system per sample curvature and the depth of focus of projection imaging system exposure field is subdivided into some bins, make the mask graph generator for single bin imaging out of focus not, the mask graph that projection imaging system provides the mask graph generator images on the sample that is installed on objective table, computer control system is determined the wobble length and the two dimensional motion of objective table according to the curvature of sphere sample, the plane mask is carried out area differentiation, realize the surface splicing photoetching of different curvature sample.

The present invention's advantage compared with prior art is:

(1) the present invention is by computer control mask graph generator, select the size of single exposure area and the exposure frequency of whole sample, exposure field is segmented, according to the curvature of the sphere sample of required photoetching and the imaging depth of focus of projection objective the plane mask is carried out area differentiation, realize the photomask surface of different curvature sample.

(2) the present invention adopts substep projection imaging technology, be the computer control system curvature per sample and the depth of focus of projection imaging system, exposure field is subdivided into some bins, make the mask graph generator for single bin imaging out of focus not, the splicing of finishing whole exposure field imaging by the swing of objective table drive sample longitude and latitude is used for the photoetching of curved surface sample, has solved the curvature of field matching problem of plane mask curved planar reformation.

(3) the present invention is made of a mask graph generator, projection imaging system and objective table, it is easy to change mask selection convenient, the bin that exposes, the splicing of exposure can be finished by the two-dimentional oscillating motion of control objective table, does not need complicated system's control, has improved reliability greatly.

(4) traditional projection lithography can only be to the planar sample photoetching, curvature difference for curved surface sample especially two samples is then powerless, and for the purpose of the present invention, only the length of the telescopic shaft of the segmentation size of need change mask graph generator bin and objective table can realize therefore having better flexibility.

(5) traditional direct-write photoetching is that point-to-point processing cooperates the work stage lifting, directly writes though can realize curved surface, and efficient is extremely low, is area differentiation and the present invention adopts, and production efficiency improves greatly.

Description of drawings

Fig. 1 is a systematic schematic diagram of the present invention;

Fig. 2 is a projection imaging system structural drawing among Fig. 1;

Fig. 3 is an objective table structural drawing among Fig. 1;

Fig. 4 is an objective table rotating mechanism synoptic diagram among Fig. 3;

Fig. 5 is a computer control principle block diagram of the present invention;

Fig. 6 is a curved surface photoetching splicing principle schematic of the present invention.

Embodiment

As shown in Figure 1, the embodiment of the invention is made up of light source 1, illuminator 2, mask graph generator 3, computer control system 4, projection imaging system 5, objective table 6.Light source 1 provides the illumination light of required exposure wavelength for etching system, after illumination light is passed through illuminator 2 parallelizations and homogenising, illumination mask graph generator 3, provide mask graph by computer control system 4 control mask graph generators 3, simultaneous computer control system 4 per sample curvature and the depth of focus of projection imaging system 5 cut apart exposure field, make not out of focus of the interior imaging of exposing unit, projection imaging system 5 provides mask graph to image on the sample in mask graph generator 3, objective table 6 is used to install sample, and computer control system 4 curvature is per sample determined axis of swing length and driven the splicing that the sample two dimensional motion is realized spherical surface photolithography.

The course of work of the present invention is: at first carry out the exposing unit size, curvature per sample, cut apart exposing unit by computer control system 4, determine the telescopic shaft length of objective table 6, splice photoetching then, the light that light source 1 sends forms uniform parallel illuminating bundle through illuminator 2 backs and incides on the mask graph generator 3, control by computer control system 4 makes the uniform telecentric light of formation on mask graph generator 3, this illumination light is through after the modulation of pattern generator 3, carrying the bin figure and imaging in sample surfaces on the objective table 6 by projection imaging system 5, finish the photoetching of a bin, computer control system 4 control objective tables 6 drive the splicing exposure that whole curved surface is finished in the swing of sample longitude and latitude then.

The light source 1 that adopts among the present invention can be the monochromatic source to the photoresist sensitivity such as laser, LED or high-pressure sodium lamp.Illuminator 2 is a heart cola light structures far away, and the light that light source is sent forms uniform telecentric light through illuminator on the mask graph generator, and promptly the emergent pupil of illuminator overlaps with the entrance pupil of projection imaging system.Mask graph generator 3 is to carry out spatial modulation to shining its surperficial light, produce mask pattern, its working method can adopt transmission mode, or reflection side, it comprises that mainly analogue type DMD (digital micro-mirror array), numeric type DMD, transmission type LCD (liquid crystal display device), reflective LCD etc. can carry out the device of spatial modulation to light.

As shown in Figure 2, projection imaging system 5 among the present invention is two heart projection imaging object lens far away, by front lens group 501, diaphragm 502 and rear lens group 503 constitute, after the mask pattern that produces can being carried out scaling, be imaged onto on the sample surfaces, make the photoresist sensitization on the sample, the back focus of group 501 overlaps with the front focus of back group 503 before among the present invention, diaphragm 502 is positioned at and overlaps the focus place, make its entrance pupil and emergent pupil all be in infinite distant place, in the time of can guaranteeing that like this image planes sample has out of focus slightly, the enlargement ratio of optical system remains unchanged.

As shown in Figure 3, the objective table 6 among the present invention is by sample stage 601, telescopic shaft 602, and balance staff 603, stage body 604 and two-dimentional tilting mechanism 605 are formed, and stage body 604 is supporters of objective table, and it links to each other with balance staff 603 by two-dimentional tilting mechanism 605; Balance staff 603 links to each other with sample stage 601 by telescopic shaft 602.During work, earlier sample is placed on the sample stage 601, computer control system 4 curvature is per sample adjusted telescopic shaft 602 length, make the oscillation centre of two-dimentional tilting mechanism 605 be positioned at the centre of sphere place of sample, two dimension tilting mechanism 605 drives balance staff 603, drives the splicing of sample realization system exposure by telescopic shaft 602 and sample stage.

As shown in Figure 4, two-dimentional tilting mechanism 605 is made up of mutually orthogonal X rotating shaft 6051 and Y rotating shaft 6052, and by the adjusting adaptation different curvature sample exposure of telescopic shaft 602, balance staff 602 is finished the bin splicing by two-dimentional oscillating machine 605 swings.

As shown in Figure 5, computer control system 4 of the present invention is used to control the area differentiation of mask graph generator 3, regulate the telescopic shaft 602 coupling sample curvature of objective table 6, control two-dimentional tilting mechanism 605 pivot angles and finish the bin splicing, the face shape curvature by sample and the depth of focus of projection objective system 5 are determined the bin size of mask graph generator 3, determine the length of objective table 6 telescopic shafts 602 and the X rotating shaft 6051 rotational angle theta x and the Y rotating shaft 6052 rotational angle theta y of rotation axis 605.

The orthogonal projection of sphere differentiation element is a square, determines the length of side of square shaped cells to make the depth of focus of the height of the spherical crown of this foursquare circumscribed circle correspondence on the sample less than projection imaging system 5 according to the curvature of sphere sample; The limit of square shaped cells is X rotating shaft 6051 corners and Y rotating shaft 6052 rotational angle theta x, the θ y of rotation axis 605 to the subtended angle of the sample centre of sphere; Regulate the length of telescopic shaft 602, make the height of center sum of telescopic shaft 602 length and sphere sample equal the spherical radius of sample.

As shown in Figure 6, curved surface photoetching splicing principle of the present invention signal, in the exposure process, system finishes the exposure of bin, and the latitude θ x direction of objective table 6 is done θ x stepping, finish the splicing exposure of this latitude on the sample after, objective table 6 longitude θ y directions are done θ y stepping, and then repeat latitude θ x direction splicing exposure, and so repeatedly, up to the photoetching of finishing whole sample.

Claims

1. spherical surface photolithography system with area differentiation, it is characterized in that: it is made up of light source (1), illuminator (2), mask graph generator (3), computer control system (4), projection imaging system (5) and objective table (6); Light source (1) provides the illumination light of required exposure wavelength for etching system, after this illumination light is passed through illuminator (2) parallelization and homogenising, illumination mask graph generator (3), provide mask graph by computer control system (4) control mask graph generator (3), simultaneous computer control system (4) per sample curvature and the depth of focus of projection imaging system (5) exposure field is subdivided into some bins, make mask graph generator (3) for single bin imaging out of focus not, the mask graph that projection imaging system (5) provides mask graph generator (3) images on the sample that is installed on objective table (6), computer control system (4) is determined the wobble length and the two dimensional motion of objective table (6) according to the curvature of sphere sample, the plane mask is carried out area differentiation, realize the surface splicing photoetching of different curvature sample.

2. the spherical surface photolithography system with area differentiation according to claim 1 is characterized in that: described lighting source (1) comprises laser instrument or led light source, high-pressure sodium lamp for the monochromatic source to the photoresist sensitivity.

3. the spherical surface photolithography system with area differentiation according to claim 1, it is characterized in that: described illuminator (2) is heart cola light structures far away, the light that light source is sent forms uniform telecentric light through illuminator on the mask graph generator, promptly the emergent pupil of illuminator overlaps with the entrance pupil of projection imaging system.

4. the spherical surface photolithography system with area differentiation according to claim 1, it is characterized in that: the working method of described mask graph generator (3) adopts transmission mode, or the reflection mode, it comprises: analogue type DMD, numeric type DMD, transmission type LCD, reflective LCD.

5. the spherical surface photolithography system with area differentiation according to claim 1, it is characterized in that: described projection imaging system (5) is two heart projection imaging object lens far away, be that object lens are made up of two positive lens groups, the back focus of preceding group overlaps with the front focus of back group, make its entrance pupil and emergent pupil all be in infinite distant place, when guaranteeing that the image planes sample has out of focus slightly, the enlargement ratio of optical system remains unchanged.

6. the spherical surface photolithography system with area differentiation according to claim 1 is characterized in that: described objective table (6) is by sample stage (601), telescopic shaft (602), and balance staff (603), stage body (604) and two-dimentional tilting mechanism (605) are formed; Stage body (604) is the supporter of objective table, and it links to each other with balance staff (603) by two-dimentional tilting mechanism (605); Balance staff (603) links to each other with sample stage (601) by telescopic shaft (602); During work, earlier sample is placed on the sample stage (601), computer control system (4) curvature is per sample adjusted telescopic shaft (602) length, make the oscillation centre of two-dimentional tilting mechanism (605) be positioned at the centre of sphere place of sample, two dimension tilting mechanism (605) drives balance staff (603), drives the splicing of sample realization system exposure by telescopic shaft (602) and sample stage.