CN1702481A - Method for melting and forming micro lens array utilizing halftone mask photo etching - Google Patents
Method for melting and forming micro lens array utilizing halftone mask photo etching Download PDFInfo
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- CN1702481A CN1702481A CN 200410009113 CN200410009113A CN1702481A CN 1702481 A CN1702481 A CN 1702481A CN 200410009113 CN200410009113 CN 200410009113 CN 200410009113 A CN200410009113 A CN 200410009113A CN 1702481 A CN1702481 A CN 1702481A
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Abstract
This invention provides a new method for forming a micro-lens array by means of half tone mask and hot melt technique. Comparing with prior art, the method not only reduces greatly the demand of mask machine precision required by micro-structural formation, but also expand greatly processing scope of traditional half tone mask method, can prepare micro-structure with bilge of between several hundred nanometers and a hundred micrometers approximated, caliber of between 100 micrometers and several millimeters.
Description
Affiliated technical field
The present invention relates to a kind ofly adopt half-tone mask and in conjunction with the new method of hot-melt technology forming microlens array.
Background technology
But no matter the microarray optical element, still at civil area has all obtained widely use at military, scientific research field owing to have in light weight, advantages such as volume is little, flexible design array.The continuous relief micro-lens array manufacturing method is the focus of research always.Existing microarray optical element manufacturing process mainly contains gray scale mask method, electron beam, the straight literary style of laser beam, photoetching hot melt etc.But all there is defective in various degree in these methods.
Electron beam is similar with the principle of work of the straight literary style of laser beam.Two kinds of systems at first focus on electron beam or laser beam, and photoetching material is carried out the pointwise exposure, and how many energy that is obtained by certain point on the resist comes this embossment depth of final decision.This method equipment needed thereby complexity, make efficiency is low.Probably need tens hours for 3 cun square binary figures, process time can be longer when making solid type high relief device.In addition, laser direct writing system costs an arm and a leg, and complete machine needs nearly 1,000,000 dollars; Laser direct-writing resolution and depth of focus have determined it can not make the continuous relief element of relief depth greater than 5 μ m.
The photoetching hot melt is a kind of little relief moulding method of comparative maturity, and this method at first adopts the binary mask figure to carry out static exposure on the resist surface, forms the micro relief profile of isolated island shape.Utilize the anticorrosive additive material of high temperature fused state will be subjected to the spherical characteristics forming microlens array of surface tension effects contraction formation then.This method only is suitable for making the relatively large protruding microlens array of numerical aperture, because be subjected to the restriction of factor such as hot melt critical angle, this method is difficult to make small value aperture microlens array and other micro optical elements such as recessed microlens array and microprism.
Traditional half-tone mask method is mainly utilized the binary coding mask, and the light intensity on resist surface is carried out modulation, can obtain certain micro relief profile after the development.The disclosed half-tone mask method of " MicroelectronEngineering " magazine 23 volume 449-454 pages or leaves of publishing in 1994 is inquired into this.But because it need adopt the spatial filtering optical projection system, so the making scope of microlens array has been subjected to serious restriction.Be difficult to be made into valuable device.This technology not only needs to adopt the mask graph of electron beam, ion beam technology machining high-precision, and in exposure process, also must adopt spatial filtering system cancellation shadow tone luminous point, and mask graph is projected to the resist surface, form needed continuous gray-scale distribution.So the exposure system complexity, the working depth of embossment will be subjected to the serious of depth of focus, and cause the micro relief profile high frequency loss easily.
Summary of the invention
Technology of the present invention is dealt with problems and is: the shortcoming that overcomes existing microarray optical element manufacturing process, a kind of half-tone mask photoetching hot melt micro-lens forming method that can make various microarray optical elements fast and effectively is provided, this method is in order to solve the problem that runs in the half-tone mask method, with the half-tone mask method method of micro optical element of being shaped that combines with the photoetching hot-melt technology.
Technical solution of the present invention is: half-tone mask photoetching hot melt micro-lens forming method, its characteristics are to comprise the following steps:
(1) the shadow tone mask is designed and made to structural parameters and the face shape according to the target microlens array; Because the quantified precision of half-tone mask depends on the surface smoothness that lenticular radius-of-curvature of target and the expection of target lenticule obtain.Therefore the surface smoothness that is obtained by lenticular radius-of-curvature of target and the expection of target lenticule is determined the quantified precision of half-tone mask.The proportional relation of fluctuating of the then main and little embossment of target of the gray-scale distribution of mask.
(2) the resist applied thickness is carried out accurate Calculation, coating, preceding baking.Utilize mask to the photoresist surface contact, near or projection exposure; The applied thickness of the strict design of this Technology Need resist, when applied thickness was not enough, the resist flowability was relatively poor, and surface tension can't be eliminated the burr of lens surface.When applied thickness was too thick, surface tension might cause the distortion of lens face shape again.Therefore the selection of applied thickness has critical meaning for forming results.
(3) resist after the exposure is developed, obtain shaggy micro relief profile.
(4) it is level and smooth the high temperature hot melt to be carried out on the micro relief profile surface.The burr on resist surface after the high temperature hot melt smoothly mainly utilizes the difference of the pressure on burr surface and lenticule surface pressure to come the filtering exposure to finish.The hot melt smoothed temperature need be higher than 10 ℃ of pre-bake temperatures usually, 90～120 ℃ of temperature ranges.By the control hot molten time.Under the prerequisite that does not cause the lens face deformation, high-temperature fusion can be reduced to nanoscale by several microns with lens surface smooth finish.
The present invention compared with prior art has the following advantages:
(1) the present invention handles by the micro relief profile after the contact exposure being carried out hot melt, thereby reaches the burr of eliminating exposure back micro-structure surface, the purpose of level and smooth microstructure.Owing to removed the filtering in the classic method,, also simplified technological process simultaneously so the microstructure working depth no longer is subjected to the restriction of depth of focus.Compare with the photoetching hot melt, the rise range of work, numerical aperture scope, fill factor, curve factor that microlens array has not only been expanded in invention near 100%, can make advantage such as concavees lens, but also can be used for the shaping of continuous surface micro-structures arbitrarily such as optics position photo.
(2) the present invention compares with traditional half-tone mask method, do not need to adopt the spatial filtering system, therefore simplified the complexity of little relief moulding technology greatly, expanded the working depth scope of microstructure, 2 microns of typical half-tone mask method shaping microstructure depth capacitys, and the present invention can make extremely nearly hundred microns microstructure of hundreds of nanometer.
(3) the present invention compares with traditional photoetching hot-melt technology, not only can be suitable for making the microlens array of large-numerical aperture, but also can be used for making the microlens array of small value aperture and extra small numerical aperture, the minimum value aperture can be near NA=0, and do not have the dead band between the cell structure of making, fill factor, curve factor can be near 100%.And radio-frequency component is intact, can effectively reduce the face deformation of microstructure by designing mask figure and control conditions of exposure.The photoetching hot melt can only be made the convex lens array, and this method not only can be made convex lens, and also can realize the making of concavees lens by designing mask.
(4) the present invention can be used for making 100 microns to several millimeters of bores, the rise microlens array optical element from the hundreds of nanometer to nearly hundred microns.We not only can modulate lenticule face shape by the designing mask figure, but also can produce the non-regular micro optical element of microprism array and various other types.
(5) the present invention's various high-quality microarray optical elements that can be used for being shaped.
Description of drawings
Fig. 1 is the half-tone mask plate that adopts laser direct writing system to make.The minimum quantization precision is 5 microns.The lenticule unit size is 1500um, and horizontal ordinate is represented the bore of microlens array unit among the figure, every scale unit: 150 microns.
Fig. 2 is that the embodiment of the invention one adopts contact exposure, and the microstructure section profile figure that obtains after developing, and ordinate is represented the relief depth of microlens array unit among the figure, every scale unit: 1 micron; Horizontal ordinate is represented the bore of microlens array unit, every scale unit: 150 microns.
Fig. 3 is a sectional view of the microstructure that resist among the embodiment one obtains being handled again the microlens array that obtains after exposure, development through hot melt, and ordinate is represented the relief depth of microlens array unit among the figure, every scale unit: 1 micron; Horizontal ordinate is represented the bore of microlens array unit, every scale unit: 150 microns.
Fig. 4 is the comparison diagram of experimental result and target face shape, and curve 1 is an aim curve, and curve 2 is an experimental result, and ordinate is represented the relief depth of microlens array unit among the figure, every scale unit: 1 micron; Horizontal ordinate is represented the bore of microlens array unit, every scale unit: 150 microns.
Embodiment
Embodiment 1, is the bore =1500 μ m that make by method of the present invention, the continuous high relief microlens array of etching depth h=5 μ m.The employing positive photoresist is a photoetching material.Its manufacturing process is as follows:
(1) at first according to the structural parameters of target microlens array and the design of face shape and make the shadow tone mask, as shown in Figure 1.Relation between the surface smoothness that expection obtains according to the lenticular radius-of-curvature of target and target lenticule and the quantified precision of half-tone mask.Calculate desire and obtain surface smoothness less than 20 microns microstructure, the mask quantified precision needs 10.3 microns, gets 10 microns in the experiment.And with this size as quantifying unit, the fluctuating of the little embossment of target is converted to the density function of the unit of zones of different mask, utilize computing machine to generate data, and directly write the making mask plate.
(2) calculate the resist applied thickness, and utilize mask to the photoresist surface contact, near or projection exposure; Flowing law according to colloid in the fluid mechanics.Calculate and to guarantee that burr has the moving required applied thickness 3 μ m of performance of enough high currents in the reflow process.The required resist thickness of lens itself is 3.5 μ m, therefore at least need be at resist surface applied 6.5 μ m.And baking before adopting 100 ℃.
(3) resist after the exposure is developed, obtain shaggy micro relief profile, as shown in Figure 2.
(4) it is level and smooth the high temperature hot melt to be carried out on the micro relief profile surface, as Fig. 3.The burr on resist surface after the high temperature hot melt smoothly mainly utilizes the difference of the pressure on burr surface and lenticule surface pressure to come the filtering exposure to finish.The hot melt smoothed temperature need be higher than 10 ℃ of pre-bake temperatures usually, so temperature range is selected 110 ℃.After resist surface burr smoothly falls, stop reflow process immediately.Otherwise will cause the deformation of lens, cause face shape error.
Finish the embossment of continuous surface microlens array and make, obtain the continuous relief microlens array of bore 1500um.As shown in Figure 3, the profile graphics of this microlens array shows that its high frequency loss is few.Fig. 4 shows that the profile graphics of this microlens array (curve 1) compares with typical curve (curve 2), and error is less.
Claims (3)
1, half-tone mask photoetching hot melt forming microlens array approach is characterized in that: mainly finish by following steps:
(1) the shadow tone mask is designed and made to structural parameters and the face shape according to the target microlens array;
(2) utilize mask to the photoresist surface contact, near or projection exposure;
(3) resist after the exposure is developed, obtain shaggy micro relief profile;
(4) it is level and smooth the high temperature hot melt to be carried out on the micro relief profile surface.
2, half-tone mask photoetching hot melt forming microlens array approach according to claim 1, it is characterized in that: the quantified precision of described half-tone mask depends on the surface smoothness that lenticular radius-of-curvature of target and the expection of target lenticule obtain, and quantified precision is positioned within the range of work of laser direct-writing technology, the proportional relation of fluctuating of the gray-scale distribution of mask and the little embossment of target.
3, half-tone mask photoetching hot melt forming microlens array approach according to claim 1, it is characterized in that: described high temperature hot melt smoothly be mainly used in filtering exposure finish after the burr on resist surface, the hot melt smoothed temperature need be higher than 10 ℃ of pre-bake temperatures usually, 90～120 ℃ of temperature ranges.
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100091134A CN100371738C (en) | 2004-05-24 | 2004-05-24 | Method for melting and forming micro lens array utilizing halftone mask photo etching |
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| CNB2004100091134A CN100371738C (en) | 2004-05-24 | 2004-05-24 | Method for melting and forming micro lens array utilizing halftone mask photo etching |
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| CN1702481A true CN1702481A (en) | 2005-11-30 |
| CN100371738C CN100371738C (en) | 2008-02-27 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101144978B (en) * | 2007-10-17 | 2010-12-08 | 中国科学院光电技术研究所 | Method for forming microlens array structure |
| CN101122739B (en) * | 2007-08-31 | 2011-09-28 | 中国科学院光电技术研究所 | Sub-wavelength continuous surface micro-structure preparation method based on negative refractive rate lens |
| CN102662305A (en) * | 2012-05-28 | 2012-09-12 | 中国科学院上海微系统与信息技术研究所 | Micro-lens mould structure and manufacturing method thereof |
| CN104637960A (en) * | 2013-11-13 | 2015-05-20 | 恒景科技股份有限公司 | Image sensing device |
| CN114609705A (en) * | 2022-03-08 | 2022-06-10 | 中国科学院重庆绿色智能技术研究院 | Manufacturing method of high-duty-ratio micro-lens array |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4708920A (en) * | 1985-09-16 | 1987-11-24 | Minnesota Mining And Manufacturing Company | Microlens sheet containing directional half-tone images and method for making the same |
| CN1125352C (en) * | 2000-09-25 | 2003-10-22 | 中国科学院光电技术研究所 | Method for making microlens array |
| JP2003029418A (en) * | 2001-07-10 | 2003-01-29 | Pohang Eng College | Manufacturing method for structure using high energy light source |
-
2004
- 2004-05-24 CN CNB2004100091134A patent/CN100371738C/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101122739B (en) * | 2007-08-31 | 2011-09-28 | 中国科学院光电技术研究所 | Sub-wavelength continuous surface micro-structure preparation method based on negative refractive rate lens |
| CN101144978B (en) * | 2007-10-17 | 2010-12-08 | 中国科学院光电技术研究所 | Method for forming microlens array structure |
| CN102662305A (en) * | 2012-05-28 | 2012-09-12 | 中国科学院上海微系统与信息技术研究所 | Micro-lens mould structure and manufacturing method thereof |
| CN104637960A (en) * | 2013-11-13 | 2015-05-20 | 恒景科技股份有限公司 | Image sensing device |
| CN114609705A (en) * | 2022-03-08 | 2022-06-10 | 中国科学院重庆绿色智能技术研究院 | Manufacturing method of high-duty-ratio micro-lens array |
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| CN100371738C (en) | 2008-02-27 |
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