New phase shifting mask with self-aligned phase shifters for a quarter micron photolithography

Nitayama, A.; Satō, Takashi; Hashimoto, Kohji; Shigemitsu, Fumiaki; Nakase, Makoto

doi:10.1109/iedm.1989.74227

Cited by 29 publications

(20 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We examined other kinds of phase-shifting mask such as chrome-less and the edge-contrast enhancement type. [7] Figure 1 1 shows the simulated light intensity distribution of chrome-less and edge-contrast enhancement type phase-shifting mask for 0.4gm L/S. This indicates that edge-contrast enhancement type gives better light intensity contrast than chrome-less type.…”

Section: Application For the Alternating Type Phase-shifting Maskmentioning

confidence: 85%

Novel process for phase-shifting mask fabrication

et al. 1992

View full text Add to dashboard Cite

In this new process for phase-shifting mask fabrication, molybdenum silicide (MoSi) is used as an optical shield layer and spin-on glass (SOG) as a phase-shifter layer. Chromium is employed as an etch-stopper during SOG etching. Cr etch-stopper will be removed at the end of the process, therefore all optical problems related to an etch-stopper are avoided. This Cr etch-stopper is also useful in inspection and repair of shifter remaining defects. At first, we will describe the fabrication process including the shifter-defect inspection and repair.Secondary, we will discuss the phase-shifting mask accuracy and its influence to the printed resist pattern when using the alternating type phase-shifting mask. Lastly,we will mention the application result of development of lithography for 64Mbit DRAM using this process.

show abstract

Section: Application For the Alternating Type Phase-shifting Maskmentioning

confidence: 85%

Novel process for phase-shifting mask fabrication

et al. 1992

View full text Add to dashboard Cite

show abstract

“…6(a)]. For the example 8 The total window metric is not without shortcomings. One is the assumption that the effect of focus change on linewidth variation is linear.…”

Section: B Analysis Of Complex Patternsmentioning

confidence: 96%

“…Since the 0 and 180 regions are, at least theoretically, 5 of equal transmittance, phase interaction is complete. Thus alternating PSM's are sometimes classified as strong PSM's whereas attenuated PSM's are classified as 4 Other types of PSM's such as rim [8] and chromeless [9] are not considered because of design and practicality issues. 5 In an actual alternating PSM, mask topography effects cause transmittance imbalance [25] which can be partially or, in some cases, totally corrected [26], [27].…”

Section: Optical Enhancement Techniquesmentioning

confidence: 99%

See 1 more Smart Citation

Level-specific lithography optimization for 1-Gb DRAM

Wong

Ferguson

Mansfield

et al. 2000

IEEE Trans. Semicond. Manufact.

103

View full text Add to dashboard Cite

A general level-specific lithography optimization methodology is applied to the critical levels of a 1-Gb DRAM design at 175-and 150-nm ground rules. This three-step methodology-ruling out inapplicable approaches by physical principles, selecting promising techniques by simulation, and determining actual process window by experimentation-is based on process latitude quantification using the total window metric. The optimal lithography strategy is pattern specific, depending on the illumination configuration, pattern shape and size, mask technology, mask tone, and photoresist characteristics. These large numbers of lithography possibilities are efficiently evaluated by an accurate photoresist development bias model. Resolution enhancement techniques such as phase-shifting masks, annular illumination and optical proximity correction are essential in enlarging the inadequate process latitude of conventional lithography.

show abstract

“…This method has a resolution limitation fixed by the wavelength of exposure light and NA of the projection lens. To improve the above limitation, several types of PSM exposure methods have been proposed [l], [2], [3]. Some of them had been succeeded to practical use.…”

Section: Introductionmentioning

confidence: 99%

New concept phase shifting masks based on projection lens design

Ogita¹

30th Annual Conference of IEEE Industrial Electronics Society, 2004. IECON 2004

View full text Add to dashboard Cite

2Absrrac-For the purpose of shortening turn around time (TAT) and costs of Phase-Shifting Mask (PSM) fabrication, we proposed a new concept of PSM composed of an opaque pattern substrate and a phase shifter substrate. It was considered that this PSM has the disadvantage of high wave-front aberration. In order to solve this problem, we have designed a high NA (0.75), very low aberration (0.0017 I ) reduction projection lens system.Based on this design, we found that wave-front aberration of phase shirter substrate (0.09 inches thickness) between the mask and projection lens was reduced from 033141 to O.DO891by projection lens system optimization of mask and imaging positions. We measured the intensity profiles of this prototype PSM using AMIS (Zeiss optical simulation microscope) and checked the intensity profies of this PSM were better than that of the conventional PSM. I IntroductionOpticaI exposure method using ultraviolet light is main way of LSI fabrication. This method has a resolution limitation fixed by the wavelength of exposure light and NA of the projection lens. To improve the above limitation, several types of PSM exposure methods have been proposed [l], [2], [3]. Some of them had been succeeded to practical use.Recently, shortening TAT and lowering the costs of the PSM fabrication for sub-micron LSI became a more significant task. For this purpose we have proposed a two-layer PSM composed of an opaque pattern substrate and a phase shifter substmte [4], [SI. In a previous study, we have reported a quarter micron pattern obtained by using a two-layer PSM and an i-line, low NA (0.43) stepper [6j. Two-layer PSM is able to compensate the printed CD (critical dimension) imbalance between shifter and non-shifter region, because of shielding the passing light at phase shifter edge [7], [8].In fig. 1 light intensity simulation data of conventional and two-layer alternating PSM are presented. Because the opaque pattern and the phase shifler pattern are formed on the separate substrates, this PSM can be easily fabricated. (a) ~mwntarsl alterst rg E M (b) hwleyerdtemiw E M Llgm 0 8 (AU) 02 Int-ty 06 0 4 0 -0 4 02 0 02 0 4 ++ -0 2 0 02 0 4 lmtlm (!Ami P h a l (lid 1-m n 6 3 Md5. DISumli-on& Fig. 1 and two layer PSM Light intensity profiles of conventional PSM In fig. 2 it is shown a comparison of fabrication time chart between conventional PSM and two-layer PSM. Costs of PSM are depend on TAT and fabrication process yield. Two-layer PSM had TAT and costs ments of PSM fabrication, because opaque pattern and phase shifter pattern were formed independently. TAT of two-layer PSM was less than 3 days. On the other hand, average TAT of conventional PSM was 7 days. T A d s f d -W A U -b n mu1 --------.-, it TI I Fig.2 Time chart of conventional and Two layer PSM fabricationHowever, generally it was considered two-layer PSM had high aberrations of shifter glass plate between opaque mask pattern and projection lens. The projection lens system for LSI fabrication has a very high precision and complexity, and is treated as ...

show abstract

New phase shifting mask with self-aligned phase shifters for a quarter micron photolithography

Cited by 29 publications

References 1 publication

Novel process for phase-shifting mask fabrication

Novel process for phase-shifting mask fabrication

Level-specific lithography optimization for 1-Gb DRAM

New concept phase shifting masks based on projection lens design

Contact Info

Product

Resources

About