CN211741831U - Two-photon maskless exposure system - Google Patents
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- CN211741831U CN211741831U CN202020458866.8U CN202020458866U CN211741831U CN 211741831 U CN211741831 U CN 211741831U CN 202020458866 U CN202020458866 U CN 202020458866U CN 211741831 U CN211741831 U CN 211741831U
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- 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
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Abstract
The utility model discloses a two-photon maskless exposure system, which comprises a light source, a beam expanding unit, an illuminating unit, an optical engine array, a substrate and a mobile platform, wherein the light source is used for outputting laser beams of visible light or near infrared light; the beam expanding unit is used for increasing the area of a light spot incident to the laser beam so as to enable the laser beam incident to the incident surface of the optical engine array through the illuminating unit; the illumination unit is used for uniformly processing the energy of each point of an incident laser beam spot, the optical engine array is used for generating an exposure pattern required by exposure, the movable platform is installed on the stable platform and used for moving a substrate required to be exposed, the substrate is coated with a photoresist layer, the exposure beam emitted by the optical engine array irradiates the photoresist layer, and the exposure pattern is converted onto the substrate. The utility model discloses the resolution ratio of image when can effectively improve maskless exposure can high-efficient large tracts of land exposure fast to improve production efficiency and production quality.
Description
Technical Field
The utility model relates to a maskless photoetching technology field especially relates to a two-photon maskless exposure system.
Background
Computers, the internet, and wireless communications have changed the world economy to a great extent, and these information revolution in our daily lives is based on integrated circuit technology. Silicon chips containing hundreds of millions of transistors and integrated circuit boards containing countless integrated components are all fabricated using photolithographic techniques. Photolithography techniques place spatial information into the substrate, and it is this information that determines the function of the substrate. At present, the photolithography technology has become a key technology for information leather, and almost certainly, the photolithography technology will support the future technical revolution based on nanotechnology.
A form of lithography used in silicon semiconductor processing is the OPT (chinese generic term "optical projection lithography") technique, in which a pattern is created on a mask four times the size required, and then projected onto a silicon wafer through large and very expensive reduction lenses. Although the OPT technology is advancing at a rapid pace, it still has major limitations, such as: very costly (often perhaps in excess of 200 thousand dollars), and incapable of large size, large format, and fast lithography.
With the development of integrated circuits, the line width and the aperture of a conducting line on a substrate become smaller and smaller, information contained on one substrate becomes more and more, and the functions of an integrated circuit board become more and more powerful, which means that more precise photolithography technology becomes more and more important. In recent years, optical chips are rapidly developed as a device that is considered to be capable of replacing an electrical chip in the future, and a unit of one optical chip is generally a mach-zehnder structure, and in order to make the optical chip function powerful, it is necessary to construct as many mach-zehnder structures as possible per unit area. This is also similar to transistor chips, whether silicon-based optical chips or lithium niobate-based optical chips, which require precise processing of these cell structures on the chip surface by means of photolithography, and therefore the accuracy and efficiency of the processing becomes particularly important.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a two-photon maskless exposure system that can realize the exposure of large tracts of land high resolution.
In order to achieve the above object, the present invention provides a two-photon maskless exposure system, which comprises a light source, a beam expanding unit, an illuminating unit, an optical engine array, a substrate and a mobile platform, wherein the light source is used for providing a laser beam capable of inducing a photoresist to generate two-photon absorption polymerization, the light source comprises M sets of lasers, M is a natural number, and M is greater than or equal to 1, the lasers output laser beams of visible light or near infrared light; each set of laser couples laser beams output by M sets of lasers into one beam through a light guide optical fiber with M input connectors and one output connector, and the beam is projected onto an incident surface of the beam expanding unit; the beam expanding unit is used for increasing the area of a light spot of an incident laser beam, and the beam expanding unit is used for increasing the area of the light spot of the incident laser beam so that the laser beam incident to the incident surface of the optical engine array through the illuminating unit can completely cover the incident surface of the optical engine array; the illumination unit receives the laser beam processed by the beam expanding unit and then uniformly processes the energy of each point of an incident laser beam spot, the optical engine array is installed above the moving platform and used for receiving the laser beam processed by the illumination unit and generating an exposure pattern required by exposure, the moving platform is installed on a stable platform and used for moving the substrate required to be exposed, the substrate is coated with a photoresist layer, and the exposure beam emitted by the optical engine array irradiates the photoresist layer and converts the exposure pattern onto the substrate; the optical engine array is a one-dimensional array formed by arranging N optical engines, N is a natural number, and N is greater than or equal to 1.
Further, the beam expanding unit includes a first parallel grating and a second parallel grating, and the first parallel grating is disposed on a downstream optical path of the laser beam output by the light guide fiber and is configured to expand the laser beam output by the light source; the second parallel grating is arranged on a downstream optical path of the laser beam expanded by the first parallel grating, is parallel to the first parallel grating, and is used for collimating the laser beam expanded by the first parallel grating, and the angle between the first parallel grating and the laser beam output from the light guide fiber and the distance between the first parallel grating and the second parallel grating are adjusted according to the spot size and the wavelength of the laser beam output from the light guide fiber, so that all the laser beams output from the light guide fiber can be expanded by the beam expanding unit.
Further, the optical engine includes a spatial light modulator and a lens group, where the spatial light modulator is configured to divide an incident laser beam into a plurality of independent sub-beams, all the sub-beams form a beam array, each of the sub-beams is imaged by a corresponding lens in the lens group, a two-dimensional focal array arranged in order is obtained, the two-dimensional focal array is the exposure pattern, and the light field intensity of each focal point in the two-dimensional focal array is consistent.
Further, the spatial light modulator is a digital micro-reflector, each subunit in the digital micro-reflector is a unit pixel, unit pixel points obtained by imaging the subunits in an open state form the exposure pattern, and the area range and the space volume of a laser focus area capable of causing photoresist to absorb and polymerize in the unit pixel points are lambda3Is irradiated onto the substrate to correspond toIs related to the extent of the planar area of the photoresist and the properties of the photoresist, λ is the wavelength of the laser beam.
Further, the photoresist is selected from a photoresist capable of absorbing and polymerizing in an ultraviolet light region.
Further, one side of the substrate is provided with the photoresist layer, or both sides of the substrate are provided with the photoresist layer, the laser output end of the optical engine array is arranged right opposite to the photoresist layer, and the photoresist on one side or both sides is exposed.
Above-mentioned technical scheme can see, the utility model discloses two-photon polymerization system is through the femto second laser instrument that adopts the high power to become a whole beam of light decomposition by spatial light modulator into a plurality of light beam array, present two-dimensional point array on the base plate via lens, moving platform and optical engine under through the control base plate are synchronous, consequently can show improvement resolution ratio on the one hand when the large tracts of land is exposed, promote exposure quality, on the other hand can improve productivity ratio, reduce cost.
The utility model discloses mainly be applied to high accuracy printed circuit board, IC encapsulation, the two-sided exposure in LCD makes and the optical chip makes, can also be applied to other fields.
Drawings
FIG. 1 is a schematic diagram of three typical optical imaging modalities of the prior art;
FIG. 2 is a diagram illustrating the distribution of light intensity in the Alisma area in the prior art;
fig. 3 is a schematic block diagram of a two-photon maskless exposure system according to an embodiment of the present invention;
fig. 4 is a schematic block diagram of an imaging process of a two-photon maskless exposure system according to an embodiment of the present invention;
fig. 5 is a schematic block diagram of the exposure results of a two-photon maskless exposure system according to an embodiment of the present invention;
fig. 6 is a schematic layout diagram of an optical engine array according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.
Fig. 1 shows several typical optical imaging forms, and ideally, optical imaging has diffraction limit, that is, an ideal point object cannot obtain an ideal point image through imaging of an optical system, but a freon and fischer diffraction image. Furthermore, the actual object has at least two or more points in a physical sense, each of which corresponds to a point light source, as shown in fig. 1, a first imaging modality 101, a second imaging modality 102, a third imaging modality 103, a fourth imaging modality 104, a fifth imaging modality 105, and a sixth imaging modality 106, wherein the first imaging modality 101, the second imaging modality 102, and the third imaging modality 103 are different imaging modalities when the same object passes through a lens whose focusing power is gradually weakened, and the fourth imaging modality 104, the fifth imaging modality 105, and the sixth imaging modality 106 are modalities in which objects of different sizes are imaged through the same lens.
By alignment, it can be found that: both the first imaging modality 101 and the fourth imaging modality 104 can form a fraunhofer diffraction image 107, both the second imaging modality 102 and the fifth imaging modality 105 can form a fraunhofer diffraction image 108, and both the third imaging modality 103 and the sixth imaging modality 106 can form a fraunhofer diffraction image 109. The spots (two large white dots separated by the 107 region in fig. 1) formed by the two object points in the first imaging modality 101 and the fourth imaging modality 104 are widely spaced and can be easily distinguished, consistent with the freund and fischer diffraction image 107. When the lens is changed or the image spot size is reduced to the second imaging form 102 and the fifth imaging form 105, the light spots formed by the two object points are slightly overlapped, and the central alice's spot (two large white dots in closer spacing in the 108 region in fig. 1) can be still distinguished from the freund and fischer diffraction image 108, which shows that the two image points can still be distinguished. When the lens is changed or the image spot size is reduced to the third imaging form 103 and the sixth imaging form 106, the light spots formed by the two object points are overlapped seriously, and the central alice spots (two large white dots with overlapped areas in one in the 109 area in fig. 1) are overlapped together from the freund and fischer diffraction image 109, so that two independent alice spots cannot be distinguished. Figure 2 shows the light intensity distribution 200 of the alice's spot area, which, in combination with the first theoretical knowledge of the diffraction effects of optical imaging given above, has a large fraction of the light energy concentrated in the alice's spot area 201, known as the focal position.
It can be seen that the imaging resolution is closely related to, and limits, the size of the airy spot in the middle of the resulting frowns and fischer diffraction images. For optical imaging systems, the radius of the alice's spot, which is used to measure the imaging plane resolution, is
The larger wavelength results in a larger alice spot radius when imaged, which is also a limiting condition for conventional LDI techniques. The imaging area of the conventional LDI technique will cause the area of the photoresist to polymerize as much as or greater than its area, so that the conventional LDI technique can only use a shorter wavelength exposure beam (e.g., uv light) and requires a lens with a very strong focal length capability, which is too costly for conventional LDI exposure.
In view of this, the embodiment of the present invention provides a two-photon maskless exposure system, which is to increase the energy of the laser beam to induce the two-photon absorption polymerization of the photoresist during the exposure, thereby increasing the imaging resolution. Therefore, the optical diffraction limit is broken through, and the pursuit of small-size radius of the Alice spot in the prior art is abandoned.
As shown in fig. 3, the two-photon maskless exposure system according to an embodiment of the present invention includes a light source 301, a beam expanding unit 302, an illumination unit 303, an optical engine array, a substrate 305, and a moving platform 306.
The light source 301 is used to provide a high power laser beam that can initiate two-photon absorption polymerization of the photoresist. Theoretically, two-photon absorption polymerization means that electrons at a low energy level cannot jump to a high energy level by absorbing energy of one photon, but the electrons can complete one-time jump from the low energy level to the high energy level by continuously absorbing energy of two photons to cause photochemical reaction, so that the photoresist generates two-photon absorption polymerization and is cured, the phenomenon belongs to the field of nonlinear optics, the optical field intensity of incident light is depended on, and meanwhile, the photon energy also needs to meet the requirement (2hv is more than or equal to E0-Eg). With reference to fig. 2, since two-photon absorption depends on the light field intensity of incident light, only the shadow region 202 (two-photon absorption polymerization region) can satisfy the requirement for the alice's spot region 201, and thus compared with single-photon absorption polymerization, the two-photon absorption polymerization region is smaller and mainly concentrated near the focus, and therefore the resolution of imaging can be significantly improved by selecting the two-photon absorption technique instead of the single-photon absorption technique used in the conventional LDI exposure.
In order to provide a high power beam for initiating two-photon absorption polymerization of the photoresist, the light source 301 is implemented in many ways, such as shown in fig. 3, which includes M sets of lasers 311, where M is a natural number and is greater than or equal to 1. In this embodiment, the laser 311 is a femtosecond visible laser, and the output laser wavelength is 780nm, which is relatively long and harmless to human body. Since the two-photon absorption probability is proportional to the square of the incident light intensity, the femtosecond pulse can accumulate high-density photons in a very short time range, and the embodiment obtains a large two-photon absorption probability through a visible femtosecond laser. For example, when a femtosecond laser with average power of 1W, repetition frequency of 80MHz and pulse width of 80fs is used and focused to a spot with diameter of 1um by a limiting objective lens, the peak power density at the focal point can reach 20TW/cm2Two-photon absorption processes are very easily induced at such high peak power densities. Of course, the laser 311 may also be a visible light or near-infrared laser (including a continuous wave laser, a nanosecond laser, a picosecond laser, and a femtosecond laser), and these lasers can output high-power visible light or near-infrared light, so as to provide a high-energy laser beam for the subsequent two-photon absorption polymerization.
Each set of lasers 311 can couple the light beams output by the M sets of lasers 311 into one beam through a light guide fiber 321 having M input connectors and one output connector, and project the beam onto the incident surface of the beam expanding unit 302. Under the condition that A is larger than 1, a plurality of high-power laser beams can be coupled into one beam through the light guide fiber 321, so that the power of the laser beams obtained by coupling is further improved, and higher-power exposure beams are provided for initiating two-photon absorption polymerization of the photoresist.
Since the energy of the laser beam output by the light source 301 is high, and the beam spot size of the beam is small, it is not possible to directly cover the beam on the incident surface of the spatial light modulator 314 in the entire optical engine array, and therefore, the beam expanding unit 302 is used to enlarge the laser beam, which at least covers the incident surface of the spatial light modulator 314 in the entire optical engine array.
It should be noted that the beam expanding unit 302 of this embodiment uses a parallel grating, and a prism or other optical device with a beam expanding function may be used instead.
Specifically, as shown in fig. 3, a first parallel grating 312 is disposed on an outgoing light path of the laser beam, and the first parallel grating 312 is used for expanding the laser beam output by the light source 301. Meanwhile, a second parallel grating 322 parallel to the first parallel grating 312 is further disposed on a downstream optical path of the expanded laser beam, and the laser beam expanded by the first parallel grating 312 may be further collimated by the second parallel grating 322.
The angle between the first parallel grating 312 and the laser beam output from the light guide fiber 321 and the distance between the first parallel grating 312 and the second parallel grating 322 are both adjustable, and are mainly adjusted according to the spot size and the wavelength of the laser beam output from the light guide fiber 321, so as to ensure that all the laser beams output from the light guide fiber 321 can be subjected to beam expansion processing by the beam expansion unit 302, where the "beam expansion processing" refers to increasing the spot area of the laser beam. The embodiment of using the parallel grating to increase the spot size of the laser beam is completely opposite to the prior art that needs to reduce the spot size of the laser beam.
The illumination unit 303 receives the laser beam expanded and collimated by the beam expanding unit 302, and then uniformly processes the energy of each point of the incident laser beam spot, so that the light field intensity of each point on the incident laser beam spot reaching the optical engine array is basically the same, and the light field intensity of each focus in the focus array obtained by the optical engine array is consistent. In this embodiment, the illumination unit 303 can obtain a large-sized high-power light field with uniform light intensity, so as to provide a large-sized high-power exposure light beam with uniform light intensity for the optical engine array.
As a preferred embodiment of the illumination unit 303, it includes a collimating lens group, an incident diaphragm and an optical integrator, wherein the collimating lens group is configured to receive the laser beam emitted from the beam expanding unit 302 and converge the laser beam to facilitate irradiation to the optical integrator via the incident diaphragm. The incident diaphragm is used for receiving the laser beams emitted from the collimating lens group and blocking the light rays which cannot be converged so as to avoid the damage of devices caused by the fact that useless light rays irradiate the periphery of the optical integrator for a long time. The optical integrator is used for receiving the laser beams emitted from the incident diaphragm and uniformly processing the energy of each point of laser beam spots through multiple reflections.
The optical engine array is used for receiving the laser beam after being homogenized by the illumination unit 303 and generating a pattern required for exposure. The optical engine array includes a × B optical engines 304, and all the optical engines 304 may be arranged in an array of a rows and B columns, or in an array of B rows and a columns, where a may be equal to B, or may not be equal to B. Since the pattern to be exposed is different for each area on the substrate 305, the dot columns generated by each optical engine 304 in the optical engine array are different during the actual exposure process.
In one embodiment, to improve the efficiency of imaging, the optical engine array is a one-dimensional array of N optical engines 304, N being a natural number, and N being greater than or equal to 1. Of course, arrays larger than one-dimensional can also be used, and in this case, the rows or columns need to be arranged in a staggered manner as shown in fig. 6, and the dashed arrow in fig. 6 indicates the moving direction of the optical engine 304. However, an optical engine array of such a configuration would be mechanically large, and considering space constraints, an optical engine array is optimized as a one-dimensional array.
As shown in FIG. 4, as a preferred embodiment for implementing the optical engines 304, each optical engine 304 includes a spatial light modulator 314 and a lens group 324. The spatial light modulator 314 is configured to divide an incident laser beam into a plurality of independent sub-beams, all of which form a beam array, where each sub-beam is imaged by a corresponding lens in the lens group 324, so that a two-dimensional ordered focal array, which is a required exposure pattern, can be obtained by the optical engine 304.
It should be noted that, by means of the dodging process of the illumination unit 303, the light field intensity of each point on the light spot of the incident laser beam reaching the spatial light modulator 314 is substantially the same, so that the light field intensity of the sub-beam emitted through the spatial light modulator 314 can also be substantially the same, and further, the light field intensity of each focus in the focus array obtained by the lens group 324 is the same, so when the optical engine array irradiates the exposure pattern to the photoresist, the energy in the same action time is the same, and the effect of initiating the polymerization of the photoresist is the same.
Since a single focus generated by a single beam of light employed in the conventional two-photon polymerization technology is changed into a multi-beam focus array by using a Digital Micromirror (DMD), the efficiency of two-photon polymerization and the large-format processing speed are greatly improved. In the embodiment, a two-photon (multi-photon) absorption technology is combined with the spatial light modulator, and a large amount of focal arrays are obtained through the spatial light modulator, so that large-area rapid exposure is realized, and favorable conditions are provided for improving the exposure efficiency of the embodiment.
Referring to fig. 4, spatial light modulator 314 may employ digital micro-mirrors (DMD), and a specific embodiment in which spatial light modulator 314 is controlled using digital micro-mirrors (DMD) is described below.
The projection area of the laser beam emitted by the lighting unit 303 completely covers the incident surfaces of all the sub-units in the digital micro-mirror (DMD), each sub-unit in the digital micro-mirror (DMD) reflects the sub-beam projected to the projection surface thereof in the incident laser beam to a preset position, and then the laser beam emitted by the lighting unit 303 is decomposed into a plurality of sub-beams. Under the control of a computer, the sub-units in the open state reflect the sub-beams to the lens group 324 by controlling the on/off of the sub-units in the Digital Micromirror (DMD), so as to generate a pattern 600, and the pattern 600 is converged by the corresponding lenses in the lens group 324, thereby obtaining an exposure pattern 700.
The spatial light modulator 314 may use a Liquid Crystal Light Valve (LCLV), a Liquid Crystal On Silicon (LCOS), or other spatial light modulators besides digital micro-mirrors (DMD).
Therefore, the utility model discloses two-photon maskless exposure system, the laser beam of the high power through the femto second laser instrument output that adopts the high power, for exposure in-process photoresist two-photon absorption polymerization provides sufficient light field intensity, and through the plastic in order to ensure that light beam arrival optical engine 304 time light field intensity is even everywhere on spatial light modulator, become a plurality of light beam array with a whole beam light decomposition by spatial light modulator, present two-dimensional point array on the base plate via lens, moving platform and optical engine 304 under the control base plate are synchronous, consequently can show improvement resolution ratio on the one hand when the large tracts of land is exposed, promote the exposure quality, on the other hand can improve productivity, reduce cost.
As shown in fig. 5, the following takes the example that the 6 sub-units in the Digital Micromirror (DMD) in the optical engine 304 are all in the open state, and combines the principle of two-photon absorption polymerization to describe the high resolution imaging mechanism of the two-photon maskless exposure system provided by the embodiments of the present invention.
Each of the 6 sub-units is set as a unit pixel 701, and 6 unit pixels 701 imaged by the 6 sub-units form an exposure pattern 700. The unit pixel 701 is an imaging region, and the area of the unit pixel 701 is related to the magnification of the lens group 324, such as: one pixel grid of the object plane is 10um × 10um, and the magnification of the lens in the lens group 324 is 1:1, so that the image plane unit pixel 701 is also 10um × 10um in an ideal case. Therefore, the size of the area of the unit pixel 701 can be controlled by selecting the lens group 324 of different magnification.
For the conventional maskless lithography, the unit pixel point 701 is an area causing single photon polymerization of the photoresist. However, in the two-photon maskless exposure technique according to the embodiment of the present invention, only the laser focus region 702 in the unit pixel point 701 can cause the photoresist on the substrate 305 to undergo two-photon absorption and polymerization curing, and the region other than the laser focus region 702 has light, but the light field intensity cannot cause the photoresist on the substrate 305 to undergo two-photon absorption and polymerization curing. As is characteristic of the two-photon absorption, two-photon absorption is only possible at the focal point of the objective lens with a spatial volume of about λ3(λ is the incident wavelength), then the area and spatial volume of the laser focal region 702 is approximately λ3The extent of the corresponding planar area illuminated on the substrate 305.
Of course, the lowest intensity of light that can be produced by two-photon polymerization varies from photoresist to photoresist, depending on the type of photoresist selected. The area actually capable of two-photon absorption is therefore only in the laser focus area 702, the extent of which is related to the properties of the photoresist. In this embodiment, for the laser 311 outputting high-power visible light or near-infrared light, the photoresist may be a photoresist capable of absorbing and polymerizing in an ultraviolet region on the market.
Therefore, the utility model discloses two-photon maskless exposure system through adopting high power femto second laser instrument, can show the resolution ratio when reinforcing exposure, through the synchronization of each engine in the optical engine array, can greatly improve scanning speed and breadth, consequently can show improvement resolution ratio on the one hand when the large tracts of land is exposed, promotes the exposure quality, and on the other hand can productivity gain, reduce cost.
The array of optical engines is mounted on the side of the substrate 305 coated with a photoresist layer,
the photoresist layer is disposed on one side of the substrate 305, or both sides of the substrate 305 are disposed with the laser output end of the optical engine array facing the photoresist layer, so as to ensure that the exposure beam emitted from the optical engine array irradiates the photoresist layer on one side or both sides, and the exposure pattern is transformed onto the substrate 305. Such as: a two-photon maskless exposure system may be disposed above the substrate 305 to expose the photoresist on the upper surface of the substrate 305; a two-photon maskless exposure system can also be arranged below the substrate 305 to expose the photoresist on the lower surface of the substrate 305; it is also possible to provide a two-photon maskless exposure system both above and below the substrate 305 to expose the photoresist layers on the upper and lower surfaces of the substrate 305 simultaneously.
The substrate 305 is placed on a moving platform 306, and the moving platform 306 can move along a direction perpendicular to the plane of the one-dimensional array of optical engines and the plane of the one-dimensional array of optical engines, so as to adjust the position of the substrate 305 to be exposed. The movement of the moving platform 306 is controlled by a computer (not shown), and the moving platform 306 is synchronized with the pattern generated by the one-dimensional array of optical engines as it moves within the plane of the array. The synchronization of the moving platform 306 and the spatial light modulator 314 and the synchronization of the motion of the plurality of optical engine arrays are controlled by the stepping motor system and the synchronization system, which provides favorable conditions for realizing the exposure of the fast and large-format substrate. Since the synchronization of the moving platform 306 and the spatial light modulator 314 and the synchronous control of the motion of the plurality of optical engine arrays are well known in the art, the control principle will not be described herein.
The position of the laser focus region 702 in the photoresist layer may be adjusted by movement of the moving stage 306. The position of the laser focal region 702 in the photoresist layer is continuously adjusted according to the desired topography design of the optical mold such that the desired remaining topography portion of the photoresist layer is fully cured. Here, adjusting the position of the laser focus area 702 in the photoresist layer, i.e., adjusting the cured portion of the photoresist, where the laser focus area 702 is located, the photoresist will be cured. Thus, the actual position of the laser focus region 702 in the photoresist layer can be adjusted to continuously change the cured part of the photoresist, so that the parts of the photoresist to be cured are gradually cured through two-photon absorption polymerization.
The two-photon maskless exposure system provided by the embodiment of the present invention is described in detail above, and the principle and the implementation of the present invention are explained by applying specific examples herein, and the description of the above embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the specific implementation and application scope, to sum up, the content of the present specification should not be understood as the limitation of the present invention.
Claims (10)
1. A two-photon maskless exposure system, which is characterized by comprising a light source (301), a beam expanding unit (302), an illuminating unit (303), an optical engine array, a substrate (305) and a moving platform (306), wherein the light source (301) is used for providing a laser beam capable of promoting two-photon absorption polymerization of photoresist, the light source (301) comprises a plurality of sets of lasers (311), and the lasers (311) output laser beams of visible light or near infrared light; the beam expanding unit (302) is used for increasing the area of a light spot of the incident laser beam so that the laser beam incident to the incident surface of the optical engine array through the illuminating unit (303) can completely cover the incident surface of the optical engine array; the illumination unit (303) receives the laser beam processed by the beam expanding unit (302), and then uniformly processes the energy of each point of an incident laser beam spot, the optical engine array is mounted above the moving platform (306) and is used for receiving the laser beam processed by the illumination unit (303) and generating an exposure pattern required by exposure, the moving platform (306) is mounted on a stable platform and is used for moving the substrate (305) coated with a photoresist layer, and the exposure beam emitted by the optical engine array irradiates the photoresist layer and converts the exposure pattern onto the substrate (305).
2. The two-photon maskless exposure system of claim 1, wherein each set of said lasers (311) passes through a light guiding fiber (321) having M input connectors and one output connector, said beam expanding unit (302) comprises a first parallel grating (312) and a second parallel grating (322), said first parallel grating (312) being disposed on a downstream optical path of said laser beam outputted from said light guiding fiber (321) for expanding the laser beam outputted from said light source (301); the second parallel grating (322) is disposed on a downstream optical path of the laser beam expanded by the first parallel grating (312), is parallel to the first parallel grating (312), and is configured to collimate the laser beam expanded by the first parallel grating (312).
3. The two-photon maskless exposure system of claim 2, wherein the angle of the first parallel grating (312) with respect to the laser beam output from the light guide fiber (321) and the spacing between the first parallel grating (312) and the second parallel grating (322) are set according to the spot size and wavelength of the laser beam output from the light guide fiber (321) to: all the laser beams output from the light guide fiber (321) can be expanded by the beam expanding unit (302).
4. A two-photon maskless exposure system of claim 1, wherein said optical engine (304) comprises a spatial light modulator (314) and a lens assembly (324), said spatial light modulator (314) being configured to split an incident laser beam into a plurality of individual sub-beams, all of which form an array of beams, wherein each of the sub-beams is imaged through a corresponding lens of said lens assembly (324), resulting in an ordered two-dimensional array of focal points, which is said exposure pattern (700).
5. A two-photon maskless exposure system of claim 4, characterized in that the laser beam at the output of the illumination unit (303) makes the light field intensity of each focus in the two-dimensional array of focuses uniform.
6. A two-photon maskless exposure system according to claim 4 or 5, wherein the spatial light modulator (314) is a digital micro-mirror, each sub-unit in the digital micro-mirror is a unit pixel, a unit pixel point (701) imaged by the sub-unit in the open state forms the exposure pattern (700), and the unit pixel point (701) has a region range and a spatial volume λ of a laser focus region (702) which can cause the absorption and polymerization of the photoresist3The extent of the corresponding planar area irradiated onto the substrate (305) and the properties of the photoresist are related, λ being the wavelength of the laser beam.
7. The two-photon maskless exposure system of claim 6, wherein said photoresist is selected from a photoresist capable of absorbing polymerization in the ultraviolet region.
8. The two-photon maskless exposure system of claim 6, wherein said photoresist layer is disposed on one side or both sides of said substrate (305), and wherein said laser output ends of said optical engine array are disposed opposite said photoresist layer to expose one or both sides of said photoresist.
9. The two-photon maskless exposure system of claim 1, wherein each set of said lasers (311) couples laser beams outputted from M sets of said lasers (311) into one beam through a light guiding fiber (321) having M input connectors and one output connector, and projects the beam onto the incident surface of said beam expanding unit (302).
10. The two-photon maskless exposure system of claim 1, wherein said array of optical engines is a one-dimensional array of N optical engines (304), N being a natural number, and N being greater than or equal to 1.
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| WO2005054119A2 (en) * | 2003-12-01 | 2005-06-16 | The Board Of Trustees Of The University Of Illinois | Methods and devices for fabricating three-dimensional nanoscale structures |
| CN104155851B (en) * | 2014-08-01 | 2017-11-07 | 南方科技大学 | Femtosecond laser two-photon polymerization micro-nano processing system and method |
| TW201826031A (en) * | 2017-01-10 | 2018-07-16 | 國立清華大學 | Multiphoton absorption lithography processing system |
| CN109557767A (en) * | 2017-09-25 | 2019-04-02 | 深圳市纳姆达科技有限公司 | A kind of no exposure mask projection lithography system |
| CN111352311B (en) * | 2020-03-05 | 2024-05-24 | 中山新诺科技股份有限公司 | Two-photon maskless exposure system |
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| CN111352311A (en) * | 2020-03-05 | 2020-06-30 | 中山新诺科技股份有限公司 | Two-photon maskless exposure system |
| CN111352311B (en) * | 2020-03-05 | 2024-05-24 | 中山新诺科技股份有限公司 | Two-photon maskless exposure system |
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