Reticle haze: an industrial approach

Gough, S. R.; Gérard, Xavier; Bichebois, Pascal; Roche, Agnès; Sundermann, Frank; Guyader, Véronique; Bièron, Yann; Galvier, J.; Nicoleau, S.

doi:10.1117/12.736977

Cited by 7 publications

(4 citation statements)

References 0 publications

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“…Raman analyses have been performed on these particles ( Figure 13). Raman clearly indicates that small particles are (NH 4 ) 2 SO 4 which is in good agreement with precedent studies [1][2][3]8] . Four bands of SO 4 2- [9] , identified as the totally symmetric mode ȣ 1 (A1) at 978 cm -1 , the antisymmetric stretching mode ȣ 3 (F2) at 1096 cm -1 , the bending mode ȣ 2 (E) at 453 cm -1 and ȣ 4 (F2) at 613 cm -1 , are observed in the spectrum.…”

Section: B)supporting

confidence: 89%

“…In the case of ammonium sulfate, sulfates are likely come from cleaning residues, pellicle materials while amines are mainly found in the clean room environment. A lot of publications have already described the growth mechanisms and some prevention methods have been put in place [1] : sulfate-free cleaning recipes, new pellicle materials and enhanced acid/base filtration. Despite these improvements, a haze is still detected today, mostly on the backglass.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on full 6" masks using innovative solutions for direct physico-chemical analyses of mask contamination and haze

Dussault

Pelissier

Dufaye

et al. 2011

27th European Mask and Lithography Conference

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The aim of this study is to determine the different types of haze contamination that occur in industrial conditions, using direct physico-chemical analyses on full 6'' masks leaving their pellicle intact. Contaminated masks coming from end users (ST -France) or masks fab (Toppan Photomask) have been analysed. First, references XPS analyses on specially designed blanks from Toppan have been performed. Four references have been studied by angle resolved XPS. These studies show the absence of nitrogen and sulfur contamination on SiO 2 side for the four references. On Cr side, a weak residual sulfur contamination has been observed as well as a very significant nitrogen concentration for the masks treated with a standard process. Concerning the masks treated with a sulfate free process, on Cr side, no residual sulfur has been detected by XPS, whereas few trace of nitrogen amount has been detected. Then a mask coming from the ST fab contaminated in real industrial conditions has been studied with several complementary characterisation techniques such as XPS, SEM, Raman and Tof-SIMS. Theses analyses confirm that the back glass haze on the mask is on a particle form. Two types of defects have been found: small particles (a few µm size), having a stick shape, with a very typical form indicating a crystal growth mechanism, and big particles (a few 10 µm size).The detailed physico-chemical results show the composition of the particles. Raman and Tof-Sims clearly show that small particle (with a stick form) are made of ammonium sulfate (NH 4 ) 2 SO 4 crystals. XPS, Raman and Tof-Sims indicate that big particles are a nitrogen containing polymer with a weak sulphate contamination.

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Section: B)supporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Investigation on full 6" masks using innovative solutions for direct physico-chemical analyses of mask contamination and haze

Dussault

Pelissier

Dufaye

et al. 2011

27th European Mask and Lithography Conference

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“…These finding are underscored by reports of success by fabs which have begun to employ environmental controls of reticle storage and use. 1 The analytical data comparing sulfates absorbed from airborne sources versus cleaning chemistry suggest that there is no difference in the absorbed components nor should any difference in impact on haze be expected. With data reported previously both by the authors and others it is clear that absorption from the fab environment is now dominating the level of absorbed sulfates on photomask if proper AMC control is not implemented.…”

Section: Discussionmentioning

confidence: 98%

“…2,8 Some semiconductor manufacturers have proactively addressed the issue of ambient AMC (Airborne Molecular Contamination) such as SO 2 and NH 3 during storage and exposure. 1 But implementation of such measures is still not routine across the industry. It is clear from various studies done on ammonium sulfate growth as well as from field data that AMC control is required to help mitigate haze growth.…”

Section: Introductionmentioning

confidence: 99%

Study of time dependent 193 nm reticle haze

et al. 2007

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While significant progress has been made in reducing the occurrence rate of progressive defect growth on photomasks used at 193nm, the issue continues to be a problem for many semiconductor fabs. Increasing evidence from multiple sources indicates that further reduction in haze risk involves closely controlling the storage and exposure environment of the photomask. Further controlled testing is necessary to characterize the impact of environment and individual components on growth. In this way, photomask users, equipment and material providers may be better prepared to ensure the proper storage and use of photomasks in order to reduce the risk of haze growth.In continuation of work previously reported by Toppan Photomasks, advanced test apparatus, recently designed and built, now enables researchers to generate and maintain stable and controlled levels of multiple impurities which potentially effect haze growth. Supported by on-line and off-line analytical methods and instrumentation, new experimental set-up enables accuracy in the testing and validation of the impacts of environmental variables. Different classes of pollutants in multiple combinations have been studied to more precisely characterize environmental sensitivity of varying types of 193 nm reticles. Authors report further on the study of the effect of environmental conditions on severity and rate of haze formation to provide insight into the requirements for reducing or even preventing such conditions.

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