Several maskless lithography techniques using laser or electron beam eb methods have been used in an attempt to address this problem. Ware3 reported an electron projection lithography epl. University of science and technology of china 1993 m. Electron source in this system is ncsi ballistic surface electron emitter. Prospects, progress, and challenges the resolution of electron beams is unlimited. A major improvement in maskless lithography is thus critical in order to satisfy the demands in mass production for the semiconductor industry. Electrical engineering and computer sciences in the. Maskless, resistless ion beam lithography processes by qing ji b. The direct laser writing technique 911 is a promising and economic. This technique has been used for mask writing applications as well as device engineering and in some cases chip manufacturing. Maskless and targeted creation of arrays of colour centres. Sematech meeting identifies challenges to maturing maskless lithography 21 january 2005 guided by input from more than 100 industry professionals, a sematechled steering. As such, it can potentially make nanofabrication much simpler. Various approaches have been investigated, including ebeam, micromachined mirror projection, and.
Reflective electron beam litography rebl utilizes several novel technologies to generate and expose lithographic patterns at throughputs that could make ebeam maskless lithography feasible for high volume manufacturing. Ville liimatainen, ali shah, leenasisko johansson, and quan zhou. The digital pattern generator dpg uses reflective electron optics to constantly shape the electron beam as it scans across the wafers, which are located on a rotary stage shown in fig. Sematech meeting identifies challenges to maturing. The trajectories of some electrons are marked by yellow lines. Electron beam lithography nanolithography techniques. Maskless electron beam lithography, or electron beam direct write, has been around for a long time in the semiconductor industry and was pioneered from the mid1960s onwards. We show that a beam of nitrogen ions can be focused to approximately 100 nm using focused ion beam fib technology. Similar to photolithography, substrates for ebeam lithography are coated with na resist that either crosslink when struck by electrons, rendering it less soluble in. Osa supercritical lens array in a centimeter scale. The maskless electron beam lithography system, based on massively parallel electronbeam writing strategy has the ability for lowcost production of truly unique individual chips in volume manufacturing, compatible with optical systems. Pdf maskless electron beam lithography, or electron beam direct write, has been around for a long time in the semiconductor industry and was pioneered. Here we propose and experimentally demonstrate a high numerical. The primary advantage of electron beam lithography is that it can draw custom patterns directwrite with sub10 nm resolution.
Parallel maskless optical lithography for prototyping, low. Electron beam lithography ebl is a maskless lithography technique by which complex features are produced on a substrate with very high resolution. Data path development for massive electronbeam maskless lithography paper 797035 time. Although multiaxial electronbeam lithography has been proposed to increase throughput by using multiple beams in a parallel manner. This form of maskless lithography has high resolution and low throughput, limiting its usage to photomask fabrication, lowvolume production of semiconductor devices, and research and development. Ebl is a maskless lithography, where the electron beam directly creates the ine patterns with random shapes. The electrons are reflected to a target substrate by portions of an electron opaque patterned structure having a lower voltage level and are absorbed by portions of the structure having a higher voltage level. Multiple ebeam maskless lithography uses over 10,000 electron beams working in parallel to directly write circuit patterns on a wafer, eliminating the need for the costly photomasks used in current lithography machines. Ebeam direct write ebdw as complementary lithography. The resolution of electron beams is unlimited, for practical purposes in lithography. Maskless lithographic fine patterning on deeply etched or. Jul 18, 2018 electron beam lithography ebl is a maskless lithography technique by which complex features are produced on a substrate with very high resolution. Maskless, resistless ion beam lithography unt digital library. The electron beam changes the solubility of the resist, enabling selective removal of either the exposed or nonexposed regions of the resist by immersing it in a.
Feasibility issues include the electron source, parallel operation, and lithography demonstration at 50 nm and below. Microlens arrays mlas are widely used in optical imaging, dense wavelength division multiplexing, optical switching, and microstructure patterning, etc. Us5691541a us08645,531 us64553196a us5691541a us 5691541 a us5691541 a us 5691541a us 64553196 a us64553196 a us 64553196a us 5691541 a us5691541 a us 5691541a authority us united states prior art keywords programmable array array substrate lithography system image prior art date 19960514 legal status the legal status is an assumption and is not a legal conclusion. Mapper lithography has introduced the flx1200 platform installed at cealeti. An electron source is configured to emit electrons. Nov 29, 2011 although multiaxial electron beam lithography has been proposed to increase throughput by using multiple beams in a parallel manner, there are difficulties in simultaneously regulating the. Maskless ebeam nnum 2019 introduction to maskless uvlithography ebeam writers expose with electrons electron sensitive resist needed small feature size of few nm dedicated systems dtu large, expensive and complex rasterscans each voxelfield exposure time very long hours pr. Its widespread use is due to the wide range of electron beam systems available accessing an equally wide range of electron beam energies 10 ev to 100 kev. Highresolution maskless lithography semantic scholar. Scattering probability varies as square of atomic number z, and inversely as the incident kinetic energy. Process development of a maskless n40 via level for. Electronbeam lithography 6,7 and focusedion beam 8 can realize a highresolution fabrication of the structure with complicated surface pro. Maskless, parallel patterning with zoneplate array. It uses thermal field emission filament technology and a laserinterferometer controlled stage.
An alternative to maskbased optical lithography is maskless lithography, where the layout data is directly written onto a wafer. The most commonly used form of maskless lithography today is electron beam lithography. Process development of a maskless n40 via level for security. There are optical systems available that provide maskless photolithography. Maskless, highprecision, persistent and extreme wettingcontrast patterning in an environmental scanning electron microscope. Mask less lithography provides solution in the form of several techniques which are cost effective. Lossless compression algorithms for the rebl directwrite e. An experimental apparatus has been constructed, and has achieved its first beam. Electron beam lithography lithography wiley online library. Maskless, resistless ion beam lithography unt digital. Maskless, highprecision, persistent, and extreme wetting. Techniques used for mask less lithography citeseerx. Mapper and tsmc take next step in exploring multiple ebeam. With,000 electron beams each delivering a current of na on the wafer, a throughput of 10 wph is realized for 22nm node lithography.
The nitrogen ion beam is produced using an electron cyclotron resonance ecr plasma source. Mapper and tsmc take next step in exploring multiple e. If this can be achieved in practice, it will open up the possibility of mainstream manufacturing of vlsi circuits using maskless ebeam lithography. Ebeam systems can be characterized using the same scale. Prospects, progress, and challenges the resolution of electron beams is unlimited, for practical purposes in lithography. Fabrication of microoptics elements with arbitrary surface. This is another huge step forward for mapper, said mappers ceo, dr. These properties make possible a number of new electron beam tools, including a highthroughput multibeam maskless wafer exposure tool. Taiwan influence of massively parallel ebeam directwrite pixel size on electron proximity correction. Although multiaxial electronbeam lithography has been proposed to increase throughput by using multiple beams in a parallel manner, there are difficulties in simultaneously regulating the. Our result has paved the way towards portable threedimensional maskless laser direct writing with resolution fully comparable to electron beam lithography. Electron beam lithography2,3 has recently garnered attention because of the limitations of conventional optical lithography on feature sizes less than 65 nm.
Mapper lithography is developing a maskless lithography technology based on massivelyparallel electronbeam writing in combination with high speed optical data transport for switching the electron beams. Lossless compression algorithms for the rebl directwrite. Maskless, resistless ion beam lithography processes. E beam systems can be characterized using the same scale. Maskless lithography an overview sciencedirect topics. Ebeam lithography technic basics 21 interaction volumes of the incident electron beam blue in compact samples grey depending on electron energy and atomic number z. A lithography system in which the mask or reticle, which usually carries the pattern to be printed onto a substrate, is replaced by a programmable array of binary i. The operational principle of ebl is similar to that of photolithography with the exception that ebl is a directwrite process where patterns are directly engineered onto the substrate without the. Maskless plasmonic lithography at 22 nm resolution. Focused ion beam fabrication combined with electron beam lithography 6. We developed a crestec surface electron emission lithography csel for mass production of semiconductor devices. Maskless photolithography system deep blue university of. The operational principle of ebl is similar to that of photolithography with the. Taiwan influence of massively parallel e beam directwrite pixel size on electron proximity correction.
Charged particle maskless lithography cpml2 is a derivative of ebdw that promises much higher throughput, and optical or photonic maskless lithography oml2. Nov 15, 2010 reflective electron beam litography rebl utilizes several novel technologies to generate and expose lithographic patterns at throughputs that could make ebeam maskless lithography feasible for high volume manufacturing. Semiconductor on glass photocathodes for high throughput. Physical effect of electronic bombardment in the target. Mar 10, 2003 among the four major alternative ngl approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. Us6870172b1 maskless reflection electron beam projection. Using a suitable combination of ebl tool, electron sensitive resist material and development process feature sizes of sub 10 nm can be resolved. The electrons are reflected to a target substrate by portions of an electronopaque patterned structure having a lower voltage level and are absorbed by portions of the structure having a higher voltage level. Aug 31, 2004 in a sense, one variation of maskless lithography is already in use electron beam direct write ebdw has been used for many years to develop new devices and circuit prototypes. Keep it simple dont use too many different parameters.
Data path development for massive electron beam maskless lithography paper 797035 time. A of current at 50 kv can be delivered to the wafer in such a system with a total spot diameter of 70 nm. Osa maskless multiplebeam laser lithography for largearea. In a sense, one variation of maskless lithography is already in use electron beam direct write ebdw has been used for many years to develop new devices and circuit prototypes.
Under continuos development, maskless patterning by projection. A maskless electron beam lithography system based on negative electron af. Among the four major alternative ngl approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. Electronbeam lithography often abbreviated as ebeam lithography, ebl is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electronsensitive film called a resist exposing. Jun 19, 20 our result has paved the way towards portable threedimensional maskless laser direct writing with resolution fully comparable to electron beam lithography. Development of maskless electronbeam lithography using ncsi. The proposed system offers the possibility of maskless electron beam lithography with throughput in excess of 50 wafersh 8 in. Maskless, or direct write e beam lithography has been used extensively over its history of about 40 years. However, ebl has its own unique set of problems and limitations24 and has seen few applications outside of research and mask making. Ebeam lithography, ebdw, complementary lithography, 193nm resolution, maskless lithography. This thesis investigates a focused ion beam system for maskless, resistless patterning that can be made practical for highvolume production. Development of maskless electronbeam lithography using nc.
A focused electron beam with nanometer spot size is scanned across the surface to be patterned. Maskless and targeted creation of arrays of colour centres in. However, the low throughput of most maskless methods due to the serial and slow scanning nature remains the bottleneck. University of california, berkeley 1998 a dissertation submitted in partial satisfaction of the requirements for the degree of doctor of philosophy in engineering.
Fabrication of microoptics elements with arbitrary. Osa maskless multiplebeam laser lithography for large. Other types of e beam systems with higher throughput include variable shaped beam, electron projection lithography and parallel maskless systems, the last of which has even been suggested as a. However, the light modulation capability for both the conventional refractivetype mla and planar diffractivetype mla is still staying at the diffractionlimited scale. Gradientbased optimization for efficient exposure planning. One embodiment disclosed relates to an apparatus for reflection electron beam lithography. Throughput enhancement technique for mapper maskless. High speed maskless lithography of printed circuit boards using digital micromirrors eric j.
In scanning electron beam lithography, instead of light, electron beam is used and the setup and principle. High speed maskless lithography of printed circuit boards. The raith eline is an electron beam lithography tool with a 100 mm by 100 mm travel range. The maskless electron beam lithography system, based on massively parallel electron beam writing strategy has the ability for lowcost production of truly unique individual chips in volume manufacturing, compatible with optical systems. Separate search groups with parentheses and booleans. Maskless, parallel patterning with zoneplate array lithography d. The rebl program was described in a previous article p.
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