CN100434945C

CN100434945C - IV type concave holographic grating production process

Info

Publication number: CN100434945C
Application number: CNB200610016998XA
Authority: CN
Inventors: 李文昊; 齐向东; 巴音贺希格
Original assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Current assignee: Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date: 2006-07-07
Filing date: 2006-07-07
Publication date: 2008-11-19
Anticipated expiration: 2026-07-07
Also published as: CN101101344A

Abstract

The invention is an IV-type concave holographic grating making process flow, belonging to the field of spectrum technique, relating a grating making process flow. And its technical solution comprises: substrate treatment, coating glue, front drying, holographic exposure, development, after drying, thermal melting, ion beam etching, cleaning, and plating. And it is novel, low-cost and easy to implement, especially replaces traditional reaction ion etching with photoresist thermal melting, largely reducing cost, and shortening making cycle, and it can reduce parts of system and eliminate astigmatism and coma of optical system.

Description

The method for making of IV type concave holographic grating

One, technical field:

The invention belongs to the method for making of a kind of IV type concave holographic grating that relates in the spectral technique field.

Two, background technology:

At vacuum ultraviolet, particularly grenz ray wave band, all substances all have strong absorption to optical radiation, and traditional plane grating spectrograph is owing to introduced collimating mirror and condenser, so there is the supplementary loss that is caused by collimating mirror and condenser, this is unfavorable for the collection efficiency that improves the overall optical spectrometer system.Concave grating is then comparatively superior, because concave grating has the self-focusing characteristic, does not need collimating optical system and Focused Optical system can form spectral line when imaging.Different according to the kind of aberration correction and degree, concave holographic grating develops into the IV type from the I type:

Adopt two bundle directional lights to make light source, the interference fringe of record two plane wave fronts can obtain and the suitable holographic gratings of pitch ruling grating such as plane or concave surface on plane or concave light grid base base.This concave holographic grating is called I type concave holographic grating, and is the same with pitch grating such as delineation concave surface etc., has bigger remaining aberration.

Making II type concave holographic grating can come record with two-phase dry bulb ground roll, two spherical wave centers be measuring point all on Rowland circle, II type concave holographic grating is often used as makes the Rowland circle spectrograph.

III type concave holographic grating also is known as the flattened field grating usually, is used to make the flattened field spectrometer, and this type of spectrometer imaging in one plane helps using ccd array to receive like this.

When the light path of IV type concave holographic grating is taken in design, consider the structural parameters and the performance requirement of the monochromator that uses it, originally certain aberration that is placed in meeting appearance on the instrument is offset them when taking consciously, perhaps in employed wave band, make it be reduced to minimum level.So before calculating IV type concave holographic grating, must determine form, performance and the parameter of monochromator earlier, meet the IV type concave holographic grating of monochromator requirement with computer solving, determine the position of measuring point.

Use IV type concave holographic grating can eliminate the aberration of optical system, the size that can dwindle spectral instrument reduces the amount of parts of forming, and improves image quality, resolving power and the measuring accuracy of optical instrument.Therefore, IV type concave holographic grating can be used for spectrometer in a large number, and this grating becomes indispensable optical element, and can be used for having unique advantage in the multiband optical splitter and simple monochromator of visible, ultraviolet region.

Three, summary of the invention

The technical problem to be solved in the present invention is: the method for making that a kind of IV type concave holographic grating is provided.The technical scheme of technical solution problem is as shown in Figure 1: comprise base treatment 1, gluing 2, preceding baking 3, holographic exposure 4, develop 5, back baking 6, hot melt 7, ion beam etching 8, cleaning 9, plated film 10.Detailed content is as follows, base treatment 1: the grating substrate should be adopted no bubble, no marking, polished concave surface K9 optical glass, clean concave surface K9 substrate of glass with lime carbonate, guarantee substrate surface cleaning, fine and close, dry, to help the adhesion of photoresist and substrate surface.Gluing 2: in cleaned grating substrate, apply photoresist, adopt the rotary process gluing, be about to photoresist and drop in the grating substrate, obtain the photoresist film of uniformity by centrifugal rotation.Photoresist adopts the Shiply1805 positive photoresist, rotational speed during gluing is controlled in 1700～5000 rev/mins of scopes, its whirl coating time is no less than 30 seconds, can guarantee the abundant volatilization of solvent and the homogeneity of film thickness like this, and applied thickness is 300～700nm.The rotational speed of bondline thickness during mainly by gluing controlled, and the high more then glue-line of rotating speed is thin more, and the low more then glue-line of rotating speed is thick more.Mainly rely on the incisure density of concave grating when selecting bondline thickness, the big more glue-line that then requires of incisure density is thin more.Before baking 3: baking oven is put in the grating substrate that will apply behind the photoresist, and the oven temperature to 90 ℃ of raising then picks up counting taking-up after 30 minutes.The effect of preceding baking is to remove photoresist inexpungible solvent when air drying, and it is more tight that photoresist is contacted with substrate.Holographic exposure 4: the interference field that optical element formation is put in the grating substrate that scribbles photoresist that will handle well exposes.The interference field that optical element forms comprises Kr as shown in Figure 2 ⁺Laser instrument 11, plane mirror 12, half-reflecting half mirror 13, plane mirror 14 and 15, pinhole filter 16 and 17, interference field 18 and grating substrate 19.At Kr ⁺Be equipped with plane mirror 12 on the optical axis of the laser beam direction of propagation of laser instrument 11, plane mirror 12 and optical axis angle at 45; On the reflected light light path of plane mirror 12, be equipped with half-reflecting half mirror 13, its half-reflection and half-transmission face and optical axis angle at 45; On the optical axis of the reflecting surface of half-reflecting half mirror 13 and transmission plane emergent light, be equipped with plane mirror 14 and plane mirror 15 respectively; On the optical axis of the reflection ray of plane mirror 14 and plane mirror 15, be equipped with pinhole filter 16 and pinhole filter 17 respectively; The intersectional region of pinhole filter 16 and pinhole filter 17 emission light has formed interference field 18; Be built-in with the grating substrate 19 of passing through preceding baking at interference field 18, the central point of grating substrate 19 is positioned at the center of interference field 18.Time shutter is 10～120 seconds, controls time shutter length according to the model and the interference field intensity of photoresist.Develop 5: developer solution is put in the grating substrate after the exposure, developer solution is 5 ‰ NaOH solution, develop at normal temperatures, development time is 10～60 seconds, development time is subjected to the influence of time shutter, solution level, because photosensitization makes the sinusoidal figure of the dissolved formation of the potential raster graphic of photoresist, have grating fringe in the grating substrate this moment, is also referred to as photoresist grating.Back baking 6: the photoresist grating after will developing is put into baking oven, and the oven temperature to 120 ℃ of raising then picks up counting taking-up after 30 minutes.The effect of back baking is an adhesive capacity of improving photoresist and substrate, and removes the solvent that stays after the development.Hot melt 7: baking the time is not taken out photoresist grating after finishing from baking oven, and the oven temperature to 160 ℃ of directly raising picks up counting, and takes out after 30 minutes, and this step is called hot melt.The reflow process fundamental purpose is to reduce surfaceness, will be heated to molten condition to photoresist exactly, and under its capillary effect, the burr of scored surface just is eliminated.Ion beam etching 8: because the physical property and the optical property of photoresist grating are poor more than being made in K9 holographic grating on glass, so photoresist grating will be transferred to substrate of glass, this step adopts Ar ion beam etching technology well to realize this process.Photoresist grating behind the hot melt inserted in the LKJ-1C-150 ion beam etching machine that Beijing Advance ion beam research institute produces carry out ion beam etching, etching time is 10-30 minute, and etching time is by etching depth and ion beam energy decision.Cleaning 9: the grating behind the ion beam etching is put into acetone soln wash remained on surface photoresist and impurity.Plated film 10: the grating behind the ion beam etching that cleaning is intact is put into vacuum coating equipment AM aluminum metallization film, is used for strengthening grating diffration efficient.

Good effect of the present invention is: IV type concave surface holographic grating production method of the present invention be novel, cheaply, be easy to realize, particularly making with photoresist, hot melt has replaced traditional reactive ion etching, save cost widely, shortened fabrication cycle, utilize this method can produce high-quality concave grating, the application of this kind grating in optical system can reduce the parts of system, can eliminate the astigmatism and the coma of optical system.

Four, description of drawings

Fig. 1 is the process flow diagram of the inventive method.Fig. 2 is the IV type concave holographic grating exposure device light channel structure synoptic diagram that the inventive method adopted in the 4th step.

Five, embodiment

The present invention implements by preparation method's flow chart step shown in Figure 1, and is specific as follows:

1, cleans no bubble, no marking, polished concave surface K9 substrate of glass with lime carbonate;

2, coating Shiply1805 positive photoresist 300～700nm is thick on concave surface K9 substrate of glass, and bondline thickness is realized according to incisure density and control centrifuge speed;

3, baking before the baking oven is put in the grating substrate that will apply photoresist, and rising oven temperature to 90 ℃ picks up counting, and takes out after 30 minutes;

4, the grating substrate is put into interference field and exposed 10～120 seconds, control time shutter length according to the model and the interference field intensity of photoresist;

5,5 ‰ NaOH solution is put in the grating substrate after will exposing, and develops at normal temperatures 10～60 seconds, and development time is subjected to the influence of time shutter, solution level;

6, the photoresist grating after will developing is put into the baking of baking oven back, and rising oven temperature to 120 ℃ picks up counting, and takes out after 30 minutes;

7, the oven temperature that further raises carries out hot melt, and hot melting temperature is 160 ℃, and hot molten time is 30 minutes;

8, adopt Ar ion etching technology to carry out ion beam etching, etching time is 10-30 minute, and etching time is by etching depth and ion beam energy decision;

9, cleaning is with residual photoresist and the impurity of grating surface behind the acetone soln removal ion beam etching;

10, in vacuum coating equipment to the grating surface AM aluminum metallization film after cleaning.

Claims

1, the method for making of IV type concave holographic grating is characterized in that: comprise base treatment (1), gluing (2), preceding baking (3), holographic exposure (4), development (5), back baking (6), hot melt (7), ion beam etching (8), cleaning (9), plated film (10); Detailed content is as follows, base treatment (1): the grating substrate should be adopted no bubble, no marking, polished concave surface K9 optical glass, cleans concave surface K9 substrate of glass with lime carbonate; Gluing (2): in cleaned grating substrate, apply photoresist, adopt the rotary process gluing, be about to photoresist and drop in the grating substrate, obtain the photoresist film of uniformity by centrifugal rotation; Photoresist adopts the Shiply1805 positive photoresist, and the rotational speed during gluing is controlled in 1700～5000 rev/mins of scopes, and its whirl coating time is no less than 30 seconds, and applied thickness is 300～700nm; Before baking (3): baking oven is put in the grating substrate that will apply behind the photoresist, and the oven temperature to 90 ℃ of raising then picks up counting taking-up after 30 minutes; Holographic exposure (4): the interference field that optical element formation is put in the grating substrate that scribbles photoresist that will handle well exposes, and the time shutter is 10～120 seconds; Develop (5): developer solution is put in the grating substrate after the exposure, and developer solution is 5 ‰ NaOH solution, develops at normal temperatures, and development time is 10～60 seconds; Back baking (6): the photoresist grating after will developing is put into baking oven, and the oven temperature to 120 ℃ of raising then picks up counting taking-up after 30 minutes; Hot melt (7): baking the time is not taken out photoresist grating after finishing from baking oven, and the oven temperature to 160 ℃ of directly raising picks up counting, and takes out after 30 minutes; Ion beam etching (8): the photoresist grating behind the hot melt inserted in the LKJ-1C-150 ion beam etching machine that Beijing Advance ion beam research institute produces carry out ion beam etching, etching time is 10-30 minute; Cleaning (9): the grating behind the ion beam etching is put into acetone soln wash remained on surface photoresist and impurity; Plated film (10): the grating behind the ion beam etching that cleaning is intact is put into vacuum coating equipment AM aluminum metallization film.