CN102621827B - Maskless exposure system and exposure method thereof - Google Patents
Maskless exposure system and exposure method thereof Download PDFInfo
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- CN102621827B CN102621827B CN201210121376.9A CN201210121376A CN102621827B CN 102621827 B CN102621827 B CN 102621827B CN 201210121376 A CN201210121376 A CN 201210121376A CN 102621827 B CN102621827 B CN 102621827B
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Abstract
The invention provides a maskless exposure system and an exposure method thereof. The maskless exposure system comprises a laser light source, a half-wave plate, a beam splitter mirror, a first light intensity attenuator, a first electric shutter, a first reflecting mirror, a beam expanding mirror, a collimating mirror, a mask support plate, a Fourier transform lens, a photorefractive crystal, a second reflecting mirror, a second light intensity attenuator, a second electric shutter, an imaging lens and a wafer support frame. Due to the adoption of the maskless exposure system provided by the invention, the quantity of masks can be reduced greatly, and cost of the masks caused by the use of multiple sets of masks is lowered.
Description
Technical field
The invention belongs to field of semiconductor manufacture, relate in particular to a kind of maskless lithography system and exposure method thereof.
Background technology
Photoetching is one of technology of semiconductor manufacturing most critical, and its exposure technique can be divided into traditional optical exposure, electron beam exposure, ion beam exposure and X ray exposure etc.
Contact exposure in traditional optical exposure technique can obtain higher resolution, but the result that repeats between mask plate and wafer to contact is on mask plate, to produce defect, and these defects will be repeated to duplicate to wafer, causes the yield of product to decline.Although the defect problem producing in contact exposure has been avoided in proximity printing, the sharply decline that has brought resolution due to the increase in gap.Projection exposure utilize optical projection image-forming principle by mask plate projection imaging to wafer, carry out contactless exposure, both obtained the resolution the same with contact exposure, avoid again contact exposure damage, polluted the drawback of mask plate, become the main flow exposure technique of current traditional optical exposure, but projection exposure technology is not still avoided the use of mask plate.Electron beam exposure is without mask plate, can be directly to scribbling the wafer drawing exposure of photosensitive material under the control of computing machine, but electron beam exposure throughput rate is low, and can produce serious proximity effect, affect the resolution of image and the precision of figure, at present electron beam exposure is only applicable to the small serial production of some key component in the making of mask plate and integrated circuit.Ion beam exposure is also without mask plate, can be directly to wafer exposure, and without proximity effect, but because alignment precision problem not yet solves, for producing in enormous quantities, need time.X ray exposure is still in the experiment development stage, not yet for producing in enormous quantities.
Improving constantly of the continuous maturation of holographic optics technology and photorefractive crystal growing technology level, the realization that makes to be applicable to the maskless lithography system produced in enormous quantities becomes possibility.As everyone knows, when the identical LASER Light Source bundle in two bundle polarization directions meets, can interfere phenomenon, at light beam overlapping region, produce light and dark spatial fringe, for example, if beam of laser light source wherein (being called light beam 1) had passed through an object (mask plate) before meeting with another bundle LASER Light Source (being called light beam 2), the all information that just have this object (mask plate) in so light and dark spatial fringe, if this light and dark spatial fringe can be recorded in a kind of material, after even light beam 1 and the original (mask plate) are removed so, only by light beam 2, irradiate recording materials and also can reproduce the original, the principle of holographic optics that Here it is.
The material that is suitable for recording this light and dark striped has multiple, and using at present the most ripe material of maximum technology is exactly photorefractive crystal, as LiBbO3, BaTiO3, SBN, KNSBN etc.; Why this type of material can record this light and dark striped, because they have photorefractive effect, when so-called photorefractive effect is subject to illumination exactly, its refractive index can be subject to the spatial modulation of light intensity, produces the index distribution corresponding with light intensity space distribution.With this type of material, as recording medium, have many good qualities, first it has angular selectivity, and each angle can record a width hologram, is convenient to multiple magnanimity record; Secondly it has erasability, is convenient to repeatedly reuse; Its record is phase hologram structure again, and diffraction efficiency is higher, can make full use of luminous energy; Last it also there is wavelength selectivity, every kind of wavelength also can corresponding a kind of hologram, is convenient to the selection of this system laser instrument used.
Summary of the invention
The present invention is directed to the problem and shortage existing in photolithographic exposure, a kind of maskless lithography system simple in structure, with low cost is provided, this system is the same with projection exposure can obtain the resolution the same with contact exposure, and more there is cost advantage than projection exposure, in exposure process without mask plate, can, directly to wafer exposure, be suitable for the production in enormous quantities of various sizes wafer.
For solving the problems of the technologies described above, the present invention proposes a kind of maskless lithography system, comprising: LASER Light Source, half-wave plate, beam splitter, the first variable optical attenuator, the first electronic shutter, the first catoptron, beam expanding lens, collimating mirror, for fixedly mask plate bracing frame, fourier transform lens, photorefractive crystal, the second catoptron, the second variable optical attenuator, the second electronic shutter, imaging len and the wafer support of mask plate; The laser that described LASER Light Source is sent arrives described beam splitter after described half-wave plate, is divided into transmitted light beam and folded light beam after described beam splitter; Described transmitted light beam arrives described the first catoptron after described the first variable optical attenuator and described the first electronic shutter, pass through again described beam expanding lens and described collimating mirror, then arrive described photorefractive crystal through described mask plate bracing frame and described fourier transform lens; Described folded light beam is after described the second catoptron, after described the second variable optical attenuator and described the second electronic shutter, arrive described photorefractive crystal again, after described smooth flanging crystal, be also placed with described imaging len and for placing the described wafer support of wafer, the front focus of described imaging len and the back focus of described fourier transform lens overlap.
Preferably, after described half-wave plate, the polarization direction of laser is identical with the e optical axis of described photorefractive crystal.
Optionally, described half-wave plate is placed perpendicular to described laser beam direction, and described half-wave plate optical axis becomes miter angle with surface level simultaneously.
Optionally, the transmitted light beam that the described mask plate bracing frame of process and described fourier transform lens arrive described photorefractive crystal is object light ripple, the folded light beam that arrives described photorefractive crystal after described the second variable optical attenuator and described the second electronic shutter is reference light wave, and the common duration scope of irradiating described photorefractive material of described object light ripple and reference light wave is 10Sec～10min.
Optionally, the light intensity proportional range of described object light ripple and described reference light wave is 1: 3-1: 15.
Optionally, described photorefractive crystal is made by photorefractive material.
Optionally, described photorefractive material is a kind of in LiBbO3, BaTiO3, SBN, KNSBN.
Optionally, also comprise a fixing rotating disk, described fixedly rotating disk is in order to fixing described photorefractive crystal.
Optionally, described photorefractive crystal is positioned in the back focus of described fourier transform lens.
Optionally, described wafer support has two wafer orientation nails, and described wafer orientation nail is fixed in wafer support by wafer and makes described wafer orientation in same position.
Optionally, the position of described mask plate bracing frame and described wafer support meets image conjugate relation.
Optionally, described half-wave plate is 1mm～500mm from the distance range of described LASER Light Source outlet, and described half-wave plate diameter range is 10mm～100mm, and the distance range between described beam splitter and described half-wave plate is 5mm～500mm.
Optionally, the diameter dimension scope of described the first variable optical attenuator is 5mm～100mm.
Optionally, the distance range 10mm～1000mm between described the first catoptron and described beam splitter.
Optionally, described beam expanding lens is aplanasia biconcave lens, and the front focus of described collimating mirror and the front focus of described beam expanding lens overlap.
Optionally, the diameter range of described beam expanding lens is 5mm～30mm, and the focal range of described beam expanding lens is 5mm～100mm, and the diameter range of described collimating mirror is 20mm～200mm, and the focal range of described collimating mirror is 30mm～500mm.
Optionally, described fourier transform lens is achromatic cemented doublet.
Optionally, the diameter range of described fourier transform lens is 20mm～200mm, and the focal range of described fourier transform lens is 30mm～500mm, and the distance range between described fourier transform lens and described collimating mirror is 5mm～1000mmm.
Optionally, the diameter dimension scope of described the second variable optical attenuator is 5mm～100mm, the distance range 10mm～1000mm between described the second catoptron and described beam splitter.
An exposure method for maskless lithography system, comprising:
Holographic recording step: the light that LASER Light Source is sent arrives beam splitter after half-wave plate is divided into transmitted light beam and folded light beam after described beam splitter; Described transmitted light beam arrives described the first catoptron after the first variable optical attenuator and the first electronic shutter, pass through again beam expanding lens and collimating mirror, through the mask plate on mask plate bracing frame and fourier transform lens, arrive the photorefractive crystal that is placed on predetermined angular again, described transmitted light beam becomes the object light ripple of the graphical information of carrying described mask plate; Described folded light beam is after the second catoptron, after the second variable optical attenuator and the second electronic shutter, arrive described photorefractive crystal again, described folded light beam becomes the reference light wave that does not carry any information, described object light ripple and reference light wave interfere at described photorefractive crystal place, form the interference pattern that carries described mask plate patterns information in described photorefractive crystal;
Step of exposure: described the first electronic shutter is set to normally off, closes the path of described transmitted light beam; Rotate described photorefractive crystal to described predetermined angular; Described the second electronic shutter is opened, to open the path of described folded light beam; Reference light wave reproduces mask plate patterns information after arriving described photorefractive crystal, after imaging len, the graphical information of mask plate is imaged on the wafer being fixed in wafer support, thereby realizes the exposure to described wafer.。
Compared with prior art, use maskless lithography system provided by the present invention, at photorefractive crystal, place interferes, and forms the interference pattern (hologram image) that carries mask pattern information in described photorefractive crystal, by reference light wave, described hologram image is rendered on wafer.In reference light wave completes the exposure process of wafer, without mask plate, just can realize the exposure to wafer.Photorefractive crystal has the registering capacity of magnanimity simultaneously, uses a photorefractive crystal just can cover all mask plates in semiconductor production process completely.With this, exposure machine for maskless lithography system can use same set of mask plate (comprising one or more mask plate) by platform, the graphical information of mask plate to be transferred on photorefractive crystal, in actual wafer is produced, only need to reference light wave by the mask plate information regeneration in record and photorefractive crystal to wafer, both can complete the exposure process to wafer.Therefore, in actual wafer is produced, after only the graphical information of a set of mask plate need to being transferred on the photorefractive crystal of each exposure machine, just can produce without many exposure machines of assurance of mask simultaneously, realize the object of many same set of mask plates of maskless lithography system share.And in order to maintain every exposure machine, produce in prior art, every exposure machine is all needed to be furnished with number cover mask plate, relatively and prior art, use maskless lithography system of the present invention, many maskless lithography systems can public same set of mask plate, thereby greatly reduces because the mask plate expenses of using many cover mask plates to bring.
Accompanying drawing explanation
Fig. 1 is maskless lithography entire system structural representation in one embodiment of the invention;
Fig. 2 is beam expanding lens structural representation in one embodiment of the invention;
Fig. 3 is collimating mirror structural representation in one embodiment of the invention;
Fig. 4 is fourier transform lens structural representation in one embodiment of the invention;
Fig. 5 is imaging lens structure schematic diagram in one embodiment of the invention;
Fig. 6 is wafer support structural representation in one embodiment of the invention;
Fig. 7 is the structural representation of wafer in one embodiment of the invention.
Embodiment
In order to make object of the present invention, technical scheme and advantage are clearer, below in conjunction with accompanying drawing, further elaborate.
Fig. 1 is maskless lithography entire system structural representation in one embodiment of the invention.Described maskless lithography system, comprising: LASER Light Source 1, half-wave plate 2, beam splitter 3, the first variable optical attenuator 4, the first electronic shutter 5, the first catoptron 6, beam expanding lens 7, collimating mirror 8, mask plate bracing frame 9, fourier transform lens 10, photorefractive crystal 11, fixedly rotating disk 12, the second catoptron 13, the second variable optical attenuator 14, the second electronic shutter 15, imaging len 16 and wafer support 17.
The light that described LASER Light Source 1 is sent arrives described beam splitter 3 after described half-wave plate 2, is divided into transmitted light beam T and folded light beam R after described beam splitter 3; Described transmitted light beam T arrives described the first catoptron 6 after described the first variable optical attenuator 4 and described the first electronic shutter 5, pass through again described beam expanding lens 7 and described collimating mirror 8, then arrive described photorefractive crystal 11 through described mask plate bracing frame 9 and described fourier transform lens 10; Described folded light beam R is after described the second catoptron 13, after described the second variable optical attenuator 14 and described the second electronic shutter 15, arrive described photorefractive crystal 11 again, after described smooth flanging crystal 11, be also placed with described imaging len 16 and for placing the described wafer support 17 of wafer, the back focus of the front focus of described imaging len 16 and described fourier transform lens 10 overlaps.
Described LASER Light Source can be solid state laser, gas laser, and any one in semiconductor laser can be single laser instrument, can be also the laser instrument that forms of a plurality of laser instruments combination any one; Can be visible laser, can be also invisible light laser instrument, and the present invention will not limit this.
Below in conjunction with Fig. 1 to Fig. 6, maskless lithography system of the present invention is described in more detail.
First, the laser beam of the vertical polarization that described LASER Light Source 1 is sent, after half-wave plate 2, is transformed into the laser beam of horizontal polarization.After described half-wave plate 2, the polarization direction of laser is identical with the e optical axis of photorefractive crystal 11.The corresponding wavelength of described half-wave plate 2 is identical with the centre wavelength of described LASER Light Source 1, and half-wave plate 2 is placed perpendicular to laser beam direction, and the optical axis of half-wave plate 2 becomes miter angle with surface level simultaneously.Described half-wave plate 2 is 1mm～500mm with the distance range in described LASER Light Source 1 exit, preferred, and described half-wave plate 2 is 10mm～30mm with the distance range in described LASER Light Source 1 exit.Described half-wave plate 2 diameter ranges are 10mm～100mm, and preferred, half-wave plate 2 diameter ranges are 15mm～40mm.
Then, light beam is divided into transmitted light beam T and folded light beam R through beam splitter 3, and the beam intensity ratio of described one-tenth transmitted light beam T and folded light beam R is 1: 1.Described beam splitter 3 can be the sheet glass that is coated with beam splitting coating, can be also cube beam splitter being bonded by two right-angle prism therebetween one deck beam splitting coatings.By the beam splitting coating of adjusting in beam splitter 3, can realize the adjustment to the beam intensity ratio of described transmitted light beam and folded light beam.Distance range between described beam splitter 3 and described half-wave plate 2 is 5mm～500mm, and preferred, described beam splitter 3 is 10mm～30mm from the distance between half-wave plate 2.
Then, described transmitted light beam T is through the first variable optical attenuator 4, then after the first electronic shutter 5, arrives the first catoptron 6.Through described the first catoptron 6, can make the light path of transmitted light beam T that 90 ° of turnovers occur, guarantee according to this compactness in the whole space of described maskless lithography system.Described the first variable optical attenuator 4 can continuously change the light intensity of described transmitted light beam T.Whether open the path of described transmitted light beam T, can realize by whether opening described the first electronic shutter 5.The position of described the first variable optical attenuator 4 and the first electronic shutter 5 can exchange mutually.The diameter dimension scope of described the first variable optical attenuator 4 is 5mm～100mm, and preferred, the diameter dimension scope of the first variable optical attenuator 4 is 1 5mm～40mm.Described the first catoptron 6 is broadband deielectric-coating high reflection mirror, to visible ray and ultraviolet light are had to highly reflective.Described the first catoptron 6 is from the distance range 10mm～1000mm between described beam splitter 3, and preferred, described the first catoptron 6 is from the distance range 50mm～100mm between described beam splitter 3.
Then, described transmitted light beam T after beam expanding lens 7 and collimating mirror 8, become the parallel transmitted light beam T/ that matches with mask plate size/.Fig. 2 is beam expanding lens structural representation in one embodiment of the invention, and described beam expanding lens 7 is aplanasia biconcave lens.Transmitted light beam T is transformed into the divergent beams with certain pore size angle after beam expanding lens 7.Fig. 3 is collimating mirror structural representation in one embodiment of the invention, and the distance between described collimating mirror 8 and described beam expanding lens 7 is determined by the focal length of selected lens, and the front focus of the front focus of described collimating mirror 8 and described beam expanding lens 7 overlaps.Described collimating mirror 8 and described beam expanding lens 7 are used in conjunction with, transmitted light beam T can be become parallel transmitted light beam T//, and can realize and amplify in proportion light beam.The focal length of adjusting collimating mirror 8 or beam expanding lens 7 can adjust parallel transmitted light beam T//spot size.The diameter range of described beam expanding lens 7 is 5mm～30mm, and the focal range of beam expanding lens 7 is 5mm～100mm.Preferably, the diameter range of described beam expanding lens 7 is 10mm～20mm, and the focal range of described beam expanding lens 7 is 10mm～50mm.The diameter range of described collimating mirror 8 is 20mm～200mm, and the focal range of described collimating mirror 8 is 30mm～500mm.Preferably, the diameter range of described collimating mirror 8 is 20mm～100mm, and the focal range of described collimating mirror 8 is 30mm～300mm.
Then, parallel transmitted light beam T//through being fixed on after the first mask plate M1 on mask plate support 9, the graphical information of the first mask plate M1 can append to described parallel transmitted light beam T//on.For convenience of description, the parallel transmitted light beam that carries the first mask plate M1 graphical information is called to object light ripple Ψ
o.Described object light ripple Ψ
ocontinue to propagate after Fourier changes lens 10, the Fourier that forms the first mask plate on the back focal plane of Fourier variation lens 10 changes spectrum.Fig. 4 is fourier transform lens structural representation in one embodiment of the invention, and described fourier transform lens 10 is achromatic cemented doublet.The back focal plane that changes lens 10 at described Fourier is placed with and is fixed on the fixedly photorefractive crystal 11 on rotating disk 12 of photorefractive crystal.Described fixedly rotating disk 12, under the drive of motor, can be realized and carry described photorefractive crystal 11 by angle continuous rotation.The diameter range of described fourier transform lens 8 is 20mm～200mm, and its focal range is 30mm～500mm.Preferably, the diameter range of described fourier transform lens 10 is 30mm～100mm, and the focal range of fourier transform lens is 30mm～300mm.Distance range between described fourier transform lens 10 and described collimating mirror 8 is 5mm～1000mmm.Preferably, the distance range between described fourier transform lens 10 and described collimating mirror 8 is 10mm～50mmm.
The folded light beam R producing after beam splitter 3, after the second catoptron 13, does not carry the folded light beam of any information and crosses the second variable optical attenuator 14 through R, then arrive photorefractive crystal 11 places after the second electronic shutter 15.For convenience, the folded light beam of not carrying any information is called to reference light wave Ψ through R
r.Described the second variable optical attenuator 14 can continuously change described reference light wave Ψ
rlight intensity.Whether open described reference light wave Ψ
rpath, can realize by whether opening described the second electronic shutter 15.The position of described the second variable optical attenuator 14 and the second electronic shutter 15 can exchange, simultaneously the second variable optical attenuator 14 and the second electronic shutter 15 also can be positioned at described the second catoptron 13 before.The diameter dimension scope of described the second variable optical attenuator 4 is 5mm～100mm, and preferred, the diameter dimension scope of the second variable optical attenuator 14 is 15mm～40mm.Described the second catoptron 13 is broadband deielectric-coating high reflection mirror, and visible ray and ultraviolet light are had to highly reflective.Distance range 10mm～1000mm between described the second catoptron 13 and described beam splitter 3, preferred, the distance range 50mm～100mm between described the second catoptron 13 and described beam splitter 3.
After catoptron 13 reflections, do not carry the reference light wave Ψ of any information
rarrive photorefractive crystal 11 places, with the object light ripple Ψ that carries the first mask plate M1 graphical information
ointerfere, at the interior formation interference pattern of described photorefractive crystal 11, interference pattern also can carry the graphical information of described the first mask plate.In order to guarantee the record effect of 11 pairs of described conoscope images of photorefractive crystal, guarantee described object light ripple Ψ
owith reference light wave Ψ
rthe described photorefractive material of common irradiation reaches the regular hour, and irradiation time is difference with different crystal material.Described object light ripple Ψ
owith reference light wave Ψ
rcommon irradiation after described 11 duration of photorefractive material, scope was 10Sec～10min, the graphical information of described the first mask plate just can be recorded in photorefractive crystal 11.In order to guarantee reference light wave Ψ
rwith object light ripple Ψ
ocan there is stable interference effect at described photorefractive crystal 11 places, the optical path distance of described transmitted light beam T from described beam splitter 3 to described photorefractive crystal 11 will equate with the optical path distance of described folded light beam R from described beam splitter 3 to described photorefractive crystal 11, while reference light wave-wave Ψ
rwith object light ripple Ψ
olight intensity ratio want suitably.Adjust described the first variable optical attenuator 4 and can adjust object light ripple Ψ
olight intensity, adjust described the second variable optical attenuator 14 and can adjust reference light wave Ψ
rlight intensity.Arrive the object light ripple Ψ at described photorefractive crystal 11 places
owith reference light wave Ψ
rlight intensity proportional range be 1: 3-1: 15.
Described photorefractive crystal 11 adopts photorefractive material to make, and photorefractive material is any one in LiBbO3, BaTiO3, SBN, KNSBN.Because photorefractive material is when being subject to illumination, the spatial modulation that its refractive index can be subject to light intensity can produce the index distribution corresponding with light intensity space distribution, so described photorefractive crystal 11 can be recorded as the index distribution in photorefractive crystal 11 by the interference pattern that carries described the first mask plate patterns information, so far the graphical information of described the first mask plate just changes into the first mask plate hologram image that carries the first mask plate 1 graphical information of described photorefractive crystal 11 interior index distribution.Therefore photorefractive material has angular selectivity, and each angle can record a width hologram image, carries the first angle of a photorefractive crystal 11 corresponding to the first mask plate hologram image of the first mask plate patterns information described in.
Adopt above-mentioned same method, described the first mask plate is replaced with to the second mask plate, rotate described fixedly rotating disk 12 described photorefractive crystal 11 is rotated to the second angle, like this, can carry in the interior formation of described photorefractive crystal 11 the second mask plate hologram image of the second mask plate patterns information, the second angle of the photorefractive crystal 11 that the second mask plate hologram image is corresponding unique.The rest may be inferred, the interior hologram image that can record i mask plate of described photorefractive crystal 11, and the i angle of the photorefractive crystal 11 that each i mask plate hologram image is corresponding unique, wherein i is greater than 1 natural number.In semi-conductive manufacture process, described mask plate can be each mask plate that uses of exposure.Because described photorefractive crystal 11 each angle can record a width hologram image, differential seat angle between every two angles depends on the angular resolution with described fixedly rotating disk 12, if fixedly rotating disk 12 has sufficiently high angular resolution, the quantity of the mask plate that described photorefractive crystal 11 can record can reach magnanimity.With respect to the magnanimity record amount of photorefractive crystal, the quantity of all mask plates that use in semiconductor production is a very little number.Therefore, use a photorefractive crystal can cover all mask plates in semiconductor production process completely, the angle of the corresponding photorefractive crystal of each piece mask plate.
Fig. 5 is imaging lens structure schematic diagram in one embodiment of the invention, and described imaging len 16 can be the single lens with imaging function, can be also the combination of a plurality of lens.Wafer support structural representation in Fig. 6 one embodiment of the invention, described wafer support 17 has two wafer orientation nails 18, and described wafer orientation nail 18 is fixed on wafer in wafer support 17.Fig. 7 is the structural representation of wafer in one embodiment of the invention, and the wafer 19 that is positioned over wafer support 17 has two grooves 20 following closely 18 correspondence positions with described wafer orientation.Described groove 20 is positioned over after described wafer support 17 described wafer 19, and groove 20 positions of wafer are just in time corresponding with the position of wafer orientation nail 18, with this, guarantee that the wafer that is at every turn positioned over wafer support 17 can be positioned same position.The size of described eyeglass bracing frame 17 determines by the size of the wafer of required exposure, can be 2 inches, 4 inches, 6 inches, 8 inches etc.
Described mask plate bracing frame 9 is between described collimating mirror 8 and described fourier transform lens 10, and described photorefractive crystal 11 is positioned on the back focal plane of fourier transform lens 10, after described wafer support 17 is positioned at imaging len.The back focal plane of the front focal plane of described imaging len 16 and described fourier transform lens 10 overlaps.The position of described mask plate bracing frame 9 and described wafer support 17 meets image conjugate relation.
An exposure method that adopts maskless lithography system of the present invention, comprising: holographic recording step and step of exposure, illustrate respectively the detailed process of each step below.
Holographic recording step: the light that described LASER Light Source 1 is sent arrives described beam splitter 3 after described half-wave plate 2, is divided into transmitted light beam T and folded light beam R after described beam splitter 3; Described transmitted light beam T arrives described the first catoptron 6 after described the first variable optical attenuator 4 and described the first electronic shutter 5, pass through again described beam expanding lens 7 and described collimating mirror 8, through the n mask plate on described mask plate bracing frame 9 and described fourier transform lens 10, arrive the photorefractive crystal 11 that is placed on n angle again, described transmitted light beam T becomes the object light ripple Ψ that carries described n mask pattern information
o; Described folded light beam R, after described the second catoptron 13, then arrives described photorefractive crystal 11 after described the second variable optical attenuator 14 and described the second electronic shutter 15, and described folded light beam R becomes the reference light wave Ψ that does not carry any information
r, described in carry the object light ripple Ψ of described n mask pattern information
owith reference light wave Ψ
rat described photorefractive crystal, 11 places interfere, and in the interior formation of described photorefractive crystal 11, carry the interference pattern of described n mask pattern information.
Step of exposure: described the first electronic shutter 5 is set to normally off, closes the path of described transmitted light beam T; Rotate described photorefractive crystal 11 to described predetermined angle theta; Described the second electronic shutter 15 is opened, to open the path of described folded light beam R; Reference light wave Ψ
rarrive described photorefractive crystal 11, angle initialization is reproduced out after imaging len 16 in the image information of the n mask plate of photorefractive crystal 11 records of n angle, the wafer in wafer support 17 is fixed in arrival, thereby realize, described wafer is carried out to the exposure corresponding with n mask plate.After end exposure, close described the second electronic shutter 15, close after the path of described folded light beam R, prepare the exposure of next wafer.
In sum, use maskless lithography system provided by the present invention, by the interference of object light ripple and reference light wave, the image information of mask plate can be recorded in the hologram image in photorefractive crystal, then by closing object light ripple path, by reference light wave, described hologram image is rendered on wafer.An angle of the corresponding photorefractive crystal of the hologram image of each mask plate simultaneously, fixing turntable rotation photorefractive crystal to the specific angle of rotating light Photorefractive like this, just can realize the exposure process of specific mask plate.In reference light wave completes the exposure process of wafer, without mask plate, just can realize the exposure to wafer.Because photorefractive crystal has the registering capacity of magnanimity, use a photorefractive crystal just can cover all mask plates in semiconductor production process completely.With this, exposure machine for maskless lithography system can use same set of mask plate (comprising several mask plates) by platform, the graphical information of mask plate to be transferred on photorefractive crystal, in actual wafer is produced, only need to reference light wave by the mask plate information regeneration in record and photorefractive crystal to wafer, both can complete the exposure process to wafer.Therefore, in actual wafer is produced, after only the graphical information of a set of mask plate need to being transferred on the photorefractive crystal of each exposure machine, just can produce without many exposure machines of assurance of mask simultaneously, realize the object of many same set of mask plates of maskless lithography system share.And in order to maintain every exposure machine, produce in prior art, every exposure machine is all needed to be furnished with number cover mask plate, relatively and prior art, use maskless lithography system of the present invention, many maskless lithography systems can public same set of mask plate, thereby greatly reduces because the mask plate expenses of using many cover mask plates to bring.Therefore greatly reduced mask plate quantity, reduced because use the expense of the mask plate bringing of many cover mask plates.
Obviously, those skilled in the art can carry out various changes and modification and not depart from the spirit and scope of the present invention invention.Like this, if within of the present invention these are revised and modification belongs to the scope of the claims in the present invention and equivalent technologies thereof, the present invention is also intended to comprise these change and modification.
Claims (20)
1. a maskless lithography system, comprising: LASER Light Source, half-wave plate, beam splitter, the first variable optical attenuator, the first electronic shutter, the first catoptron, beam expanding lens, collimating mirror, for fixedly mask plate bracing frame, fourier transform lens, photorefractive crystal, the second catoptron, the second variable optical attenuator, the second electronic shutter, imaging len and the wafer support of mask plate; The laser that described LASER Light Source is sent arrives described beam splitter after described half-wave plate, is divided into transmitted light beam and folded light beam after described beam splitter; Described transmitted light beam arrives described the first catoptron after described the first variable optical attenuator and described the first electronic shutter, pass through again described beam expanding lens and described collimating mirror, then arrive described photorefractive crystal through described mask plate bracing frame and described fourier transform lens; Described folded light beam is after described the second catoptron, after described the second variable optical attenuator and described the second electronic shutter, arrive described photorefractive crystal again, after described photorefractive crystal, be also placed with described imaging len and for placing the described wafer support of wafer, the front focus of described imaging len and the back focus of described fourier transform lens overlap.
2. maskless lithography system as claimed in claim 1, is characterized in that, after described half-wave plate, the polarization direction of laser is identical with the e optical axis of described photorefractive crystal.
3. maskless lithography system as claimed in claim 2, is characterized in that, described half-wave plate is placed perpendicular to described laser beam direction, and described half-wave plate optical axis becomes miter angle with surface level simultaneously.
4. maskless lithography system as claimed in claim 1, it is characterized in that, the transmitted light beam that the described mask plate bracing frame of process and described fourier transform lens arrive described photorefractive crystal is object light ripple, the folded light beam that arrives described photorefractive crystal after described the second variable optical attenuator and described the second electronic shutter is reference light wave, and the common duration scope of irradiating described photorefractive material of described object light ripple and reference light wave is 10Sec～10min.
5. maskless lithography system as claimed in claim 4, is characterized in that, the light intensity proportional range of described object light ripple and described reference light wave is 1:3-1:15.
6. maskless lithography system as claimed in claim 1, is characterized in that, described photorefractive crystal is made by photorefractive material.
7. maskless lithography system as claimed in claim 6, is characterized in that, described photorefractive material is a kind of in LiBbO3, BaTiO3, SBN, KNSBN.
8. maskless lithography system as claimed in claim 1, is characterized in that, also comprises a fixing rotating disk, and described fixedly rotating disk is in order to fixing described photorefractive crystal.
9. maskless lithography system as claimed in claim 1, is characterized in that, described photorefractive crystal is positioned on the back focal plane of described fourier transform lens.
10. maskless lithography system as claimed in claim 1, is characterized in that, described wafer support has two wafer orientation nails, and described wafer orientation nail is fixed in wafer support by wafer and makes described wafer orientation in same position.
11. maskless lithography systems as claimed in claim 1, is characterized in that, the position of described mask plate bracing frame and described wafer support meets image conjugate relation.
12. maskless lithography systems as claimed in claim 1, it is characterized in that, described half-wave plate is 1mm～500mm from the distance range of described LASER Light Source outlet, and described half-wave plate diameter range is 10mm～100mm, and the distance range between described beam splitter and described half-wave plate is 5mm～500mm.
13. maskless lithography systems as claimed in claim 1, is characterized in that, the diameter dimension scope of described the first variable optical attenuator is 5mm～100mm.
14. maskless lithography systems as claimed in claim 1, is characterized in that, the distance range 10mm～1000mm between described the first catoptron and described beam splitter.
15. maskless lithography systems as claimed in claim 1, is characterized in that, described beam expanding lens is aplanasia biconcave lens, and the front focus of described collimating mirror and the front focus of described beam expanding lens overlap.
16. maskless lithography systems as claimed in claim 1, it is characterized in that, the diameter range of described beam expanding lens is 5mm～30mm, the focal range of described beam expanding lens is 5mm～100mm, the diameter range of described collimating mirror is 20mm～200mm, and the focal range of described collimating mirror is 30mm～500mm.
17. maskless lithography systems as claimed in claim 1, is characterized in that, described fourier transform lens is achromatic cemented doublet.
18. maskless lithography systems as claimed in claim 1, it is characterized in that, the diameter range of described fourier transform lens is 20mm～200mm, the focal range of described fourier transform lens is 30mm～500mm, and the distance range between described fourier transform lens and described collimating mirror is 5mm～1000mmm.
19. maskless lithography systems as claimed in claim 1, is characterized in that, the diameter dimension scope of described the second variable optical attenuator is 5mm～100mm, the distance range 10mm～1000mm between described the second catoptron and described beam splitter.
20. 1 kinds of maskless lithography methods, is characterized in that, comprising:
Holographic recording step: the light that LASER Light Source is sent arrives beam splitter after half-wave plate is divided into transmitted light beam and folded light beam after described beam splitter; Described transmitted light beam arrives described the first catoptron after the first variable optical attenuator and the first electronic shutter, pass through again beam expanding lens and collimating mirror, through the mask plate on mask plate bracing frame and fourier transform lens, arrive the photorefractive crystal that is placed on predetermined angular again, described transmitted light beam becomes the object light ripple of the graphical information of carrying described mask plate; Described folded light beam is after the second catoptron, after the second variable optical attenuator and the second electronic shutter, arrive described photorefractive crystal again, described folded light beam becomes the reference light wave that does not carry any information, described object light ripple and reference light wave interfere at described photorefractive crystal place, form the interference pattern that carries described mask plate patterns information in described photorefractive crystal;
Step of exposure: described the first electronic shutter is set to normally off, closes the path of described transmitted light beam; Rotate described photorefractive crystal to described predetermined angular; Described the second electronic shutter is opened, to open the path of described folded light beam; Reference light wave reproduces described mask plate patterns information after arriving described photorefractive crystal, after imaging len, by described mask plate patterns information imaging on the wafer being fixed in wafer support, thereby realize the exposure to described wafer.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210121376.9A CN102621827B (en) | 2012-04-23 | 2012-04-23 | Maskless exposure system and exposure method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210121376.9A CN102621827B (en) | 2012-04-23 | 2012-04-23 | Maskless exposure system and exposure method thereof |
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| CN102621827A CN102621827A (en) | 2012-08-01 |
| CN102621827B true CN102621827B (en) | 2014-03-12 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2351773Y (en) * | 1998-06-09 | 1999-12-01 | 中国科学院光电技术研究所 | Holographical photoetching system |
| CN101290781A (en) * | 2008-06-18 | 2008-10-22 | 北京工业大学 | Rapid reading out system and method of holographic data storage |
| CN202512361U (en) * | 2012-04-23 | 2012-10-31 | 杭州士兰明芯科技有限公司 | Mask-free exposure system |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4600711B2 (en) * | 2000-12-14 | 2010-12-15 | 国立大学法人 筑波大学 | Hologram and manufacturing method thereof |
| US8053145B2 (en) * | 2006-05-30 | 2011-11-08 | Semiconductor Energy Laboratory Co., Ltd. | Method for manufacturing holographic recording medium and method for manufacturing semiconductor device |
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2012
- 2012-04-23 CN CN201210121376.9A patent/CN102621827B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2351773Y (en) * | 1998-06-09 | 1999-12-01 | 中国科学院光电技术研究所 | Holographical photoetching system |
| CN101290781A (en) * | 2008-06-18 | 2008-10-22 | 北京工业大学 | Rapid reading out system and method of holographic data storage |
| CN202512361U (en) * | 2012-04-23 | 2012-10-31 | 杭州士兰明芯科技有限公司 | Mask-free exposure system |
Non-Patent Citations (1)
| Title |
|---|
| JP特开2002-182547A 2002.06.26 |
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