Even though the mask features can be much larger than the wavelength of the light, phaseshift lithography is capable of producing deep subwavelength critical dimensions. The transmission characteristic is a binary one, i. Pdf diffractive phaseshift lithography photomask operating in. Osa improving resolution of superlens lithography by. Some functions like sine and cosine repeat forever and are called periodic functions. Phase shift lithography, unlike the traditional photolithography that uses opaque masks to modulate the intensity of the light, produces patterns by exploiting the optical phase. Alternating phaseshift mask altpsm binary masks a binary photomask is composed of quartz and chrome features.
Two types of phaseshift mask are commonly used in lithography. In this paper, phase shift mask errors introduced by mask making tools are investigated. The transparent phase shifting mask has an extremely simple structure consisting of the transparent substrate and the 180 phase shifter as shown in fig. Effect of attenuated phase shift mask structure on extreme. Phaseshift masks psms work by adding phase information to the mask in addition to amplitude information. This excerpt gives a succinct explanation of phaseshift masks. Its design is based on a fresnel computergenerated. 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. Resolution enhancement for advanced mask aligner lithography using phase shifting photomasks t. Phase difference and phase shift phase difference is used to describe the difference in degrees or radians when two or more alternating quantities reach their maximum or zero values previously we saw that a sinusoidal waveform is an alternating quantity that can be presented graphically in the time domain along an horizontal zero axis.
Phaseshift masks are photomasks that take advantage of the interference generated by phase differences to improve image resolution in photolithography. Psm is one of resolution enhancement technologies ret and has been widely. Improving resolution in photolithography with a phaseshifting mask. Tisinitride attenuating phaseshift photomask for 193 nm lithography. Pdf a phase shift proximity printing lithographic mask is designed, manufactured and tested. The pi phase shift is induced whereas their transmittance of electric intensity is almost equal for two neighboring slits. The halftone phaseshift mask has been in practical use for iline and krf. Phaseshifting mask, electron devices, ieee transactions on 29, 18281836 1982. A companion 15 mag fainter nux ratio of 106 is located 2. The right shift by 12 isnt necessary, but its nice because you can compare it with 1 instead of 4096 harder to remember and to tell exactly what the code is doing but since youve got bit12 there already its ok to use that instead. An alternating phase shift mask as claimed in claim 1, wherein the polysilicon layer, wherein the phase interference enhancement feature is a transparent stripe. Attenuated phaseshifting mask spie digital library. If not the masks would be 0xf0000000, 0x0f000000, 0x00ff0000 and 0x0000ffff for v, r, l and p respectively, each hex digit represents 4.
Alternating phase shift mask altpsm binary masks a binary photomask is composed of quartz and chrome features. The individual images show a the shape of the phase mask white for 0 phase shift, black for n phase shift, b the airy. 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. This components are used for phase matching in rf circuit. We have developed a new attenuating embedded phaseshift mask blank for 193 nm lithography based on novel tisinitride chemistry. 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. Continuous phaseshift lithography with a rolltype mask. The period goes from one peak to the next or from any point to the next matching point. Primary scleroderma myocardial disease cardiology suggest new definition. Phase difference is used to describe the difference in degrees or radians when two or more alternating quantities reach their maximum or zero values. An alternating phase shift mask as claimed in claim 4, wherein the polysilicon layer, wherein the transparent stripe has a width of about 50 nanometers to about 80 nanometers. The alternate or levinson psm offers considerable enhancement in image contrast and depth of focus but is limited to closely packed patterns to be efficient. Typically mosi 2 with a 68% transmission at a thickness that causes a 180 o phase shift. Photomasks can be separated into two main categories.
Light passes through the clear quartz areas and is blocked by the opaque chrome areas. Santini ieee transactions on electron devices 1984 397 optical imaging with phase shift masks mark d. A phase shift mask psm utilizes not only the light intensity distribution used in conventional masks but also the optical phase. Previously we saw that a sinusoidal waveform is an alternating quantity that can be presented graphically in the time domain along an horizontal zero axis. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. We will show consequences of the above result to prac tical phaseshifting mask design in section 4. Leaks or transmits 6% 180o phase light weak shift at edge.
The simplest type of mask a binary intensity mask bim consists of a structured opaque absorber mainly chrome on top of a transparent quartz plate. Dwsk the home of phase shift, the best music game for pc. For a positive tone resist, bright features are later removed in the development process. If you look at the values as binary numbers, youll see that they form a complete bitset from 2 0 though 2. Introduction p haseshifting masks have shown a great deal of. Alternating phase shift mask winbond electronics corp. Our approach is based on modeling the imaging mechanism of a stepper by. This is most commonly used in alternating phaseshift masks, where the linewidth becomes less and less sensitive to the chrome width on the mask, as the chrome width decreases. Euv etched phase shift mask stuart sherwin, uc berkeley, eecs center for xray optics, lawrence berkeley national labs dr. New phaseshifting mask structure for positive resist process. Transparent phase shifting mask electron devices meeting. Murata delivers high performance ltcc packaged product by multilayer ceramics integration technorogy.
Halftone phase shift mask htpsm blanks for iline 365 nm and gline 436 nm lithography, using chromium composites as a. A very successful technique is the application of phase shift masks psm in addition to the common. Depth of focus and the alternating phase shift mask. What is the main factor to control the phase shift in euvl mask.
Method for using chromeless phase shift lithography cpl masks to pattern contacts corresponding cpl masks. The phase shift mask in euvl euvl could be more easily extended to 22nm node and below by applying psm. They all have the same recommendation, with the latter superseding the former. To get the value of r shift 24, 16 for l and 0 for p. Phase shifter is the passive components which shifts the inputted signal phase in specific degree. Two software packages are being used for the simulation. 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. Oct 02, 2017 phase shift mask meaning phase shift mask definition. Tell a friend about us, add a link to this page, or visit the webmasters page for free fun content. A benefit of using phaseshift masks in lithography is the reduced sensitivity to variations of feature sizes on the mask itself. Exposing a wafer through the mask, the intensity profile is transferred into the photo resist.
We propose to apply phaseshifting mask psm to superlens lithography to improve its resolution. Phase shift is measured as the angle in degrees or radians between two points on a circle at the same time, demonstrating the progress of each wave through its cycle. Defect inspection remains a critical aspect of phase shift mask technology, as the set of printable mask defects has expanded to include those with phase effects in addition to conventional transmission effects. Phase shift mask measurements with excimer lasers205. This is most commonly used in alternating phase shift masks, where the linewidth becomes less and less sensitive to the chrome width on the mask, as the chrome width decreases. Comparative study of binary in tensity mask and attenuated phase shift mask using hyperna immersion lithography for sub45nm era taeseung eom, juntaek park, junghyun ka ng, sarohan park, sunyoung koo, jinsoo kim. Figure 4 compares the working of an alternatetype psm with a conventional binary mask.
The psm comprises of chromium slits alternatively filled by ag and pmma. 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. Phaseshift mask meaning phaseshift mask definition. Abstractthe phaseshifting mask consists of a normal transmission mask that has been coated with a transparent layer patterned to ensure that the optical. The lower panel b is a statistical plot showing normalized zscore fluorescence deviations using a timevaried phase mask. Computer simulations, taking full account of proximity effects in the mask making tools, are carried out to produce the distorted phase shift mask pattern. Materials screening for attenuating embedded phaseshift. Figure 1 compares the imaging process for a traditional cr mask and a simple form of the alternating aperture phase shift mask. In section iv, we show simulation results for design. Types of phaseshifting mask psm ron maltiel, expert. We will show consequences of the above result to prac. The most relevant types of phaseshifting masks psms and their operation principle in comparison to a conventional binary mask.
Binary and phase shifting mask design for optical lithography yong liu, student member, ieee, and avideh zakhor, member, ieee abstractwe propose a number of predistorted mask design techniques for binary and phase shifting masks. Continuous phaseshift lithography with a rolltype mask and. Phase shift masks psms work by adding phase information to the mask in addition to amplitude information. 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. The structure of capping layer is one of the main factor to influence the phase shift. Focus shift impacted by mask 3d and comparison between att. A benefit of using phase shift masks in lithography is the reduced sensitivity to variations of feature sizes on the mask itself. Figure 1 compares the imaging process for a traditional cr mask and a simple form of the alternating aperture phaseshift mask. The attenuated psm image has a sharper transition at the mask edge, resulting. 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.
The impact of phase errors on phase shifting masks, part 3. Carcia and others published thin films for phase shift masks find, read and cite all the research you need on researchgate. The piphase shift is induced whereas their transmittance of electric intensity is almost equal for two neighboring slits. Pdf focus shift impacted by mask 3d and comparison between. Pdf focus shift impacted by mask 3d and comparison. Mack, klatencor, finle division, austin, texas in previous editions of this column november 2002 and february 2003 we examined the impact of phase errors on the printing of alternating phase shifting masks psms.
Binary and phase shifting mask design for optical lithography yong liu, student member, ieee, and avideh zakhor, member, ieee abstractwe propose a number of predistorted mask design techniques for binary and phaseshifting masks. The destructive interference between two slits has greatly improved the spatial resolution and image. Or we can measure the height from highest to lowest points and divide that by 2. Characterization of binary and attenuated phase shift mask. Phaseshift mask design how is phaseshift mask design. If you do the shifting first as coos haak said then the mask would be the size of the value you want to access, in the case of v 4 bits, which would make it 0x0f, the same for r. Two types of phase shift mask are commonly used in lithography. Absorber mask phase shift mask psm euv source power limits throughput highefficiency patterning 2. We propose to apply phase shifting mask psm to superlens lithography to improve its resolution. Comparative study of binary in tensity mask and attenuated. Resolution enhancement for advanced mask aligner lithography. Typically mosi2 with a 68% transmission at a thickness that causes a 180o phase shift. Even though the mask features can be much larger than the wavelength of the light, phase shift lithography is capable of producing deep subwavelength critical dimensions. 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.
By engineering the thickness difference on adjacent structures, a 180. Phase shifting mask, electron devices, ieee transactions on 29, 18281836 1982. There exist alternating and attenuated phase shift masks. 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. Phase shift is more easily observed in sine waves where there is a single fundamental frequency and no harmonics. 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. Carcia and others published thin films for phaseshift masks find, read and cite all the research you need on researchgate. Continuous phase shift 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. Effect of attenuated phase shift mask structure on extreme ultraviolet lithography hyunduck shin, chang young jeoung 1, tae geun kim, sangsul lee, insung park 1, and jinho ahn department of nanoscale semiconductor engineering, hanyang university, 17 haengdangdong, seongdonggu, seoul 3791, korea. Binary and phase shifting mask design for optical lithography. Phase shift definition of phase shift by the free dictionary. Osa improving resolution of superlens lithography by phase. Because the mask is a repeating pattern of lines and. A binary mask consists of a transparent plate, covered with a patterned film that is opaque to uv wavelengths.
Depth of focus and the alternating phase shift mask chris a. Us20040101764a1 use of chromeless phase shift masks to. Specifically, we show that by straightforward modification of a given phaseshifting mask, we can flip the intensity pattern with respect to the optical focal plane. The alternating phase shift mask includes a transparent substrate, a lightshielding layer disposed on the transparent substrate to define a transparent array consisting of a plurality of first phase rows and a plurality of second phase rows alternately interposed between the first phase rows. It is also demonstrated that this mask structure is. The impact of phase errors on phase shifting masks, part 3 chris a. The alternate or levinson psm offers considerable enhancement in image contrast and depth of focus but is limited.
Thin halftone phase shift mask stack for extreme ultraviolet. However, it is very difficult to make a reliable and manufacturable psm. The most relevant types of phase shifting masks psms and their operation principle in comparison to a conventional binary mask. Selfinterference between the diffracted orders produces the required pitch in the. Investigation of phase shift mask distortion effect. Halftone phase shift mask htpsm blanks for iline 365 nm and gline 436 nm lithography, using chromium composites as a halftone shifter, are brought into production.
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