Multiple spaceharmonic waves are launched from the mask by diffraction, and the sawtooth optical intensity is formed by interference based on fourier synthesis after propagation through an air gap. Hahmann jenoptik gmbh, system technology division, carlzeissstrasse 1, 06900 jena, frg abstract a procedure is described to expose phase shift masks with high accuracy. An embedded attenuated phase shift mask eapsm includes an etch stop layer that can be plasma etched in a process that is highly selective to the underlying quartz substrate. This pc software is suitable for 32bit versions of windows xpvista7810. Our high quality phase masks are comparable with holographic phase masks but for a lesser cost. Simulation and optimization of phaseshift masks for printing of. Typically mosi2 with a 68% transmission at a thickness that causes a 180o phase shift. Alternating phase shifted masks are a powerful ret which can effectively double the resolution of a conventional optical lithography system. Phaseshift mask issues for 193 nm lithography by bruce.
Phaseshift masks are photomasks that take advantage of the interference generated by phase. Characterization of binary and attenuated phase shift mask blanks for 32nm mask fabrication. The influence of phase mask position upon edof system shenghsun hsieh a, zihhao lian a, chongmin chang b and chunghao tien a adepartment of photonics, national chiao tung univ. Depth of focus and the alternating phase shift mask. The impact of phase errors on phase shifting masks, part 3. There exist alternating and attenuated phase shift masks. Phaseshift masks psms work by adding phase information to the mask in addition to amplitude information.
This specification covers the characteristics specific to attenuated phase shift masks and mask blanks. A binary chromeonglass mask encodes the information about where to position resist edges using chrome with zero amplitude transmittance and glass with 100% amplitude transmittance. The aerial image simulated with the ideal alt psm feature has 9. A binary mask consists of a transparent plate, covered with a patterned film that is opaque to uv wavelengths. Simulation and fabrication of attenuated phaseshifting masks. It has been found that the combination of sio 2 for the phase. Binary and phase shift mask design for optical lithography. Phaseshifted full bridge dcdc power supply in this example circuit a phaseshifted fullbridge converter is implemented with a synchronous rectifier on the secondary. Using the simulation program solid, comprehensive simulation studies were conducted on the use of phaseshift masks for contact holes in optical lithography.
Leaks or transmits 6% 180o phase light weak shift at edge. The influence of phase mask position upon edof system. Defect inspection remains a critical aspect of phaseshift mask technology, as the set of printable mask defects has expanded to include those with phase effects in. Dwsk the home of phase shift, the best music game for pc. Perrott mit ocw frequency shift keying sends information encoded in instantaneous frequencycan build simple transmitters and receivers pagers use this modulation method issue want to obtain high spectral efficiencyneed to choose an appropriate transmit filterneed to choose an appropriate value of. The psm comprises of chromium slits alternatively filled by ag and pmma. Tisinitride attenuating phaseshift photomask for 193 nm lithography. Phase shift mask making by ebeam lithography sciencedirect. Us6544696b2 embedded attenuated phase shift mask and. Enabling reverse tone imaging for via levels using. Multiple phase masks in different positions and with different spacing. In the production of fiber and waveguide bragg gratings, the phase mask is illuminated by a highpower uv laser, typically an excimer laser or frequencydoubled gas laser. Pdf a new dimension in phaseshift masks researchgate.
As opposed to an alternating psm where all phase regions image onto the wafer. The method for patterning contacts includes illuminating a cpl mask comprising a reticle having plurality of phaseshifting features interspersed with nonphaseshifting areas with a short wavelength light source, wherein the phaseshifting features are. The major impact of small phase errors is a focus shift, so the. This system leverages the subhalf micron printing performance of the ateq core2500 combined with an optical alignment system. Attenuated phase shift mask materials for 248 and 193 nm. Continuous phaseshift lithography with a rolltype mask and application to transparent conductor fabrication moon kyu kwak1,2, jong g ok3, jae yong lee1 and l jay guo1,3 1 department of electrical engineering and computer science, university of michigan, ann arbor, mi 48109, usa. Four materials are presented which may meet optical and process requirements for use as attenuated phase shift mask films.
An interference exposure system using a phaseshifting mask was proposed for generating periodic sawtooth optical intensity profile with chirp in period. Search for abbreviation meaning, word to abbreviate, or lists of abbreviations. The 2d phase mask diffracts this illumination into multiple orders. The mask 3d effect was mitigated by adopting the phase shifting absorber stack. We propose to apply phaseshifting mask psm to superlens lithography to improve its resolution. Conventional plasma etching techniques can be utilized without damage to the underlying quartz. A method of manufacturing a phase shift mask, a method of manufacturing a flat panel display, and a phase shift mask capable of forming a fine and highly accurate exposure pattern are provided. Mask cost and profitability in photomask manufacturing. We have developed a new attenuating embedded phaseshift mask blank for 193 nm lithography based on novel tisinitride chemistry.
Attenuated phaseshifting mask spie digital library. Additional regions of the embedded phase sift layer are then exposed and trimmed to a predetermined thickness for providing the. This page was last edited on 27 september 2017, at 18. Pdf application of phase shift focus monitor in euvl. Alternating phase shift mask winbond electronics corp. Phaseshifting mask design for interference exposure of. Peak current mode control, pcmc, is implemented with a pi controller controlling the output voltage. The use of phase shift mask increased the dof or process latitude of the printed contacts from 0. The generic phase shift mask blank then defines the possible position of small features to be produced with generic phase shift mask technology, and the placement of particular features is determined by recording the positions of the boundaries of the adjacent phase shift areas, and designing or adjusting the design of the device accordingly. Application of automated design migration to alternating. Osa resolution enhancement for advanced mask aligner.
An example of phase conflicting mask designed via our algorithm is shown to outperform a simple intuitive design. The piphase shift is induced whereas their transmittance of electric intensity is almost equal for two neighboring slits. Phaseshifted full bridge dcdc power supply powersim inc. Files are available under licenses specified on their description page. Types of phaseshifting mask psm ron maltiel, expert. Characterization of binary and attenuated phase shift mask.
The sensor is constructed as a pixelated phasemask aligned to and imaged on a pixelated detector array. Principle of an alternating phaseshift mask courtesy asml 2. An alternating phase shift mask as claimed in claim 5, wherein the phase interference enhancement feature has a dimension that cannot transfer to a photoresist layer during photolithography. The application of the phaseshift method allows a significant resolution enhancement for proximity lithography in mask aligners. Taipei, taiwan abstract special types of pupil mask with the appropriate phase and transmission distribution can be used to modify the. A phaseshift mask relies on the fact that light passing through a transparent media will undergo a phase change as a function of its optical thickness. The proportion of masks within a mask set that incorporate opc and phaseshift technology is rising as the minimum ic feature sizes continue to shrink 3, 9. Citation download citation bassem hamieh, hyun chol choi, burcin erenturk, wei guo, ayman hamouda, huikan liu, gregory mcintyre, jason meiring, david moreau, alan thomas, and alexander wei enabling reverse tone imaging for via levels using attenuated phase shift mask and source optimization, proc. We applied deep uv attenuated phase shift masks psms to the quarter micron level contact hole pattern layer of a dram. Each adjacent pixel of the phasemask measures a predetermined relative phase shift between the orthogonally polarized. A binary chrome on glass mask is shown in a, and an alternating phase shift.
Us20040101764a1 use of chromeless phase shift masks to. Phaseshift masks are photomasks that take advantage of the interference generated by phase differences to improve image resolution in photolithography. Pdf phase shift mask technology is required to extend the resolution range of optical. Continuous phaseshift lithography with a rolltype mask. The destructive interference between two slits has greatly improved the.
Method for using chromeless phase shift lithography cpl masks to pattern contacts corresponding cpl masks. Furthermore, through the use of image enhancement techniques such as phaseshift masking, 193 rim lithography may dominate for feature resolution below 0. Us7115341b2 halftone phase shift mask blank, halftone. In general, attenuated phase shift masks are much less sensitive to phase errors than alternating phase shift masks. Two types of phaseshift mask are commonly used in lithography.
Light passes through the clear quartz areas and is. The attenuation and phase shift properties of an embedded attenuated phase shift mask eapsm may be independently selected. We demonstrate a phaseshifting, point diffraction interferometer that achieves high accuracy and is capable of measuring a single. Phase shift masks psm are evaluated as a possible option to push the. All structured data from the file and property namespaces is available under the creative commons cc0 license. As a result, image contrast and normalized image logslope were improved and. Phase shift assumes the role of duty cycle d in converter equations effective duty cycle is reduced by the resonant transition intervals 4 ecen 5817 reduction in effective duty cycle can be expressed as a function of the form fp zvtj, where p zvtj is a negative number similar in magnitude to 1. This paper presents results from investigations into phaseshift mask issues for 193 nm excimer laser lithography. Unlike the dark absorber of a bim, phaseshifting absorber material is not. Microelectronic engineering 21 1993 169172 elsevier 169 phase shift mask making by ebeam lithography h. Alternating phaseshift mask altpsm binary masks a binary photomask is composed of quartz and chrome features. By using an alternating aperture phase shift photomask aapsm, a resolution of 1.
Photomasks can be separated into two main categories. Us7312004b2 embedded attenuated phase shift mask with. Phase conflict areas occur in transparent areas of the mask pattern which are in close proximity to one another and which have the same phase. Phaseshift mask for euv lithography spie digital library. The individual images show a the shape of the phase mask white for 0 phase shift, black for n phase shift, b the airy pattern displayed in intensity, c the complex amplitude of the star phase shifted by the mask, d the exit pupil, e the exit pupil through the lyot stop 95% of the. Figure 1 compares the imaging process for a traditional cr mask and a simple form of the alternating aperture phaseshift mask. Selfinterference between the diffracted orders produces the.
An improved method of fabricating a phase shifting mask suitable for semiconductor manufacture includes the steps of identifying phase conflict areas in a desired mask pattern and forming phase shift bands in the phase conflict areas. The authors report on the performance of a scanned laser mask lithography system optimized for printing multilayer phaseshift masks. This example indicates that a fairly general design procedure consisting of alternating phase shifts and our optimized phaseshift mask is a viable candidate for future phaseshifting mask design. The transmission characteristic is a binary one, i. Comparative study of binary in tensity mask and attenuated. We propose an adaptive upper bound on the phase shift that effectively avoids artifacts for large motions, and an extension to phasebased image synthesis that leads to smoother tran. Referenced semi standards semi p1 specification for hard surface photomask substrates semi p2 specification for chrome thin films for hard surface photomasks semi p22 guideline for photomask defect classif. Attenuated phaseshift masks reducing sidelobe effect in. Phase shift lies within games, more precisely simulation.
Selectivity to the underlying quartz maintains a desired 180 degree phase shift uniformly across the active mask area. The mask 1 has a phase shift layer p1 that can give a phase difference of 180 to any light in a wavelength region of 300 nm or more and 500 nm or less. An alternating phase shift mask as claimed in claim 1, wherein the first phase is 0 degrees and the second phase is 180 degrees. A phasedifference sensor measures the spatially resolved difference in phase between orthogonally polarized reference and test wavefronts.
1597 572 616 696 1408 515 303 556 591 859 752 1139 719 279 1271 1224 82 1223 1410 50 1550 349 1473 75 156 136 781 1507 625 720 845 1270 7 25 272 161 95 1602 987 1051 1107 1242 1215 1148 742 383 488 434 1473 1412