Us20040101764a1 use of chromeless phase shift masks to. Pdf focus shift impacted by mask 3d and comparison. This system leverages the subhalf micron printing performance of the ateq core2500 combined with an optical alignment system. Photomasks can be separated into two main categories. Phaseshift mask for euv lithography spie digital library. Both mask design and quality of the projection optics have a large impact on the performance of a phase shift mask psm. There exist alternating 1 and attenuated phase shift masks 2. 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 configured in a pattern.
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. Depth of focus and the alternating phase shift mask chris a. 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. Bandwidthefficient digital modulation with application to. The fabrication of euvl apsm is more difficult than either the fabrication of an euvl binary mask or a conventional optical apsm. Euvl alternating phase shift mask, proceedings of spie. This is because an eapsm provides the necessary attenuation and phase shift requirements using a single layer absorber film. 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 addition to conventional. Some functions like sine and cosine repeat forever and are called periodic functions the period goes from one peak to the next or from any point to the next matching point the amplitude is the height from the center line to the peak or to the trough. 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.
Us5582939a method for fabricating and using defectfree. Phaseshift mask design how is phaseshift mask design abbreviated. The halftone phaseshift mask has been in practical use for iline and krf. All structured data from the file and property namespaces is available under the creative commons cc0 license. Pdf split of phaseshifts in phase mask for proximity. A phase shift in phase mask is split into two halfmagnitude phaseshifts in near field, resulting in fbg spectral asymmetry.
As many as 30 masks of varying price may be required to form a complete mask set. Pdf diffractive phaseshift lithography photomask operating in. Focus shift impacted by mask 3d and comparison between att. Ibsen phase masks incorporate unbeatable, interferometric holographic patterning technology into a production friendly phase mask. Resolution enhancement for advanced mask aligner lithography. We will show consequences of the above result to prac tical phaseshifting mask design in section 4. Download phase shift mask fabrication by laser microlens array. The attenuated phase shift mask of claim 3 wherein said first layer consists essentially of chromium and has a thickness within the range of about 25 to 75 nm for an incident wavelength of 365 nm. Attenuated phase shift mask advanced micro devices, inc. Phase shifting masks in displacement talbot lithography. A binary mask consists of a transparent plate, covered with a patterned film that is opaque to uv wavelengths. A conventional photomask is a transparent plate with the same thickness everywhere, parts of which are covered with nontransmitting material in order to create a pattern on.
The phase shift mask according to claim 3, wherein said intermediate auxiliary light transmitting regions which are close to each other at least has a low light permeability as compared to other auxiliary light transmitting regions. Phaseshift mask design how is phaseshift mask design. 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. Files are available under licenses specified on their description page. This displacement can be caused by a signal processing device such as an electronic amplifier or a low or highpass filter that performs certain operations on the signal, causing.
There exist alternating and attenuated phase shift masks. Therefore, the tasks of patterning, inspection and repair are much easier to accomplish than for a multilevel quartz etched or sogsio 2. Characterization of binary and attenuated phase shift mask. Or we can measure the height from highest to lowest points and divide that by 2. Our approach is based on the use of a class of optimal coherent approximations to partially coherent imaging systems described by the hopkins model. We have developed a new attenuating embedded phaseshift mask blank for 193. Pdf a phase shift proximity printing lithographic mask is designed. Phase shift masks are photomasks that take advantage of the interference generated by phase differences to improve image resolution in photolithography. Phase shift mask fabrication by laser microlens array. Embedded attenuated phase shift mask eapsm technology is one of the most utilized rets in high end mask shops today. Alternating phaseshift mask altpsm binary masks a binary photomask is composed of quartz and chrome features. Types of phaseshifting mask psm ron maltiel, expert.
Extreme ultraviolet lithography euvl alternating phase shift mask apsm or other optical enhancement techniques are likely needed for 16nm half pitch technology generation and beyond. Many authors have investigated the consequences of this phenomenon with respect to aberration free. 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. This page was last edited on 27 september 2017, at 18. Phase shift is a common term in the study of waveforms and communication of signals. Phaseshift masks psms work by adding phase information to the mask in addition to amplitude information. Depth of focus and the alternating phase shift mask. Tisinitride attenuating phaseshift photomask for 193 nm lithography. Bandwidthefficient digital modulation with application to deepspace communications jpl publication 0017 june 2001 the research described in this publication was carried out at the jet propulsion laboratory, california institute of technology, under a contract. A method for forming a defectfree phase shift mask includes forming a mask blank having a substrate, an etch stop layer, a phase shift layer and an opaque layer. Fabrication process of alternating phaseshift mask for practical use. The piphase shift is induced whereas their transmittance of electric intensity is almost equal for two neighboring slits. It refers to the displacement of two signals when propagated in a time domain. Multiple phase masks in different positions and with different spacing.
The manufacture of an embedded attenuating phase shift mask eapsm is the simplest among all the phase shift mask psm types. The errors are removed using new precompensating phase mask for. Method for using chromeless phase shift lithography cpl masks to pattern contacts corresponding cpl masks. In section iv, we show simulation results for design examples such as phase connectors, contact holes, and. Phase shift mask measurements with excimer lasers205. Resolution enhancement for advanced mask aligner lithography using phase shifting photomasks t. Impact of new mosi mask compositions on processing and. 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. Phase masks are the production tool used to write gratings in fibers and waveguides. A phase shift mask used for a lithographic process of transferring a pattern said mask comprising.
Dwsk the home of phase shift, the best music game for pc. Improving resolution of superlens lithography by phase. Diffractive phaseshift lithography photomask operating in proximity. Mack, klatencor, finle division, austin, texas one of the biggest advantages of the use of a strong phase shifting mask, such as the alternating psm, is the increased depth of focus of fine pitch patterns see the may, 2003 edition of this column. A description, with examples, of phase shift as it relates to ac signals. A binary chromeonglass mask encodes the information about where to position resist edges using chrome with zero amplitude transmittance and. In this article, well examine the impact of phase errors on the printing performance of one type of strong psm feature, the isolated. The authors report on the performance of a scanned laser mask lithography system optimized for printing multilayer phaseshift masks. Quality control of embeddedtype phaseshift mask 1995.
Topography effects and wave aberrations in advanced psmtechnology. One possible option is the combination of euvl and apsm. Phase shift mask measurements with excimer lasers the trend toward smaller feature sizes in microlithography requires not only a shift to shorter wavelength, but also the use of special techniques, so called resolution enhancement techniques. All books are in clear copy here, and all files are secure so dont worry about it. The pattern is obtained by applying free space light propagation. Two types of phaseshift mask are commonly used in lithography. I think it would be good if you could try and get phase shift onto steam so everyone can add eachother and play together and be able to use the steam workshop to. The pattern is obtained by applying free space light propagation along the 50. Characterization of binary and attenuated phase shift mask blanks for 32nm mask fabrication article pdf available in proceedings of spie the international society for optical engineering 7122. Selfinterference between the diffracted orders produces the required pitch in the.
Typically mosi2 with a 68% transmission at a thickness that causes a 180o phase shift. The phase mask is normally fabricated by one of two methods. Below is a product overview including a brief description you can also access these through the navigator to the left. Phaseshift masks are photomasks that take advantage of the interference generated by phase differences to improve image resolution in photolithography. Carcia and others published thin films for phaseshift masks find, read and cite all the research you need on researchgate. Phaseshift masks are photomasks that take advantage of the interference generated by phase. A phase shift proximity printing lithographic mask is designed. Our high quality phase masks are comparable with holographic phase masks but for a lesser cost. In this scheme during every bit duration, denoted by t, one of two phases of the carrier is transmitted. The lower panel b is a statistical plot showing normalized zscore fluorescence deviations using. Topography effects and wave aberrations in advanced psm. Phase masks corresponding to the three designs were fabricated on fused silica plates using ebeam lithography.
The psm comprises of chromium slits alternatively filled by ag and pmma. Leaks or transmits 6% 180o phase light weak shift at edge. The problem of automated design of phaseshifting masks for enhancedresolution optical lithography is examined. Phase shift masks psm are evaluated as a possible option to push the resolution limit of the. Continuous phaseshift lithography with a rolltype mask. Phase shift mask and method of manufacturing the same.
Figure 1 compares the imaging process for a traditional cr mask and a simple form of the alternating aperture phaseshift mask. The 2d phase mask diffracts this illumination into multiple orders. Experimental example of results achieved with a combination of phaseshifting mask imaging and etch slimming showing gate lengths down to 9 nm 17. Extreme ultraviolet lithography euvlembedded phaseshift mask epsm for 16nm halfpitch node technology and beyond generations will provide improvements in process window and low shadowing effect as compared to those of the conventional euvl binary mask. 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. We propose to apply phaseshifting mask psm to superlens lithography to improve its resolution. The destructive interference between two slits has greatly improved the spatial resolution and image. Zeitner1,2 1friedrich schiller universitat jena, institute of applied physics, abbe center of photonics, d 07743 jena, germany 2fraunhofer institute for applied optics and precision engineering, d07745 jena, germany. A very successful technique is the application of phase shift masks psm in addition to the common. We propose a computationally viable algorithm for the rapid design of phaseshifting masks for arbitrary twodimensional patterns. Finally, the remaining cr was stripped to obtain clear phase shifting masks. The use of mosi films which allow a small amount of the incident light to be transmitted through the opaque material, commonly 6% at a 180 degree phase shift with respect to the clear regions, allows for higher contrast and the. 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. Read online phase shift mask fabrication by laser microlens array.