Lithographic performance of an environmentally stable chemically amplified photoresist (ESCAP)

Alexander

Breyta

1997

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This paper describes the dissolution behavior of phenolic resins and resists in aqueous base solutions as measured with a quartz crystal microbalance.The dissolution kinetics of poly(4-hydroxystyrene)is linear with time, irrespective of molecular weights and polydispersities (including tandem blends). The effects of the composition of poly(4-hydroxystyrene-co-t-butyl acrylate) (ESCAP resin) and the loading of triphenylsulfonium triflate on the dissolution kinetics have been studied, revealing that the dissolution rate exponentially decreases with increasing the acrylate and triflate contents. A longer induction period is observed at a higher acrylate and triflate concentration. The dissolution inhibition effect of acid generators has been correlated with an interaction between the phenolic OH group and an acid generator molecule as studied by 13C NMR. The strong interaction of onium salts with phenol is clearly observed also in IR spectra of the above copolymer films. The quartz crystal microbalance has provided valuable information on the dissolution kinetics of exposed Shipley UVIIHS resist films, which exhibit a very fast dissolution of 30,000 A/sec. The dissolution rates of the exposed resist films have been correlated with the degrees of deprotection as determined by thickness measurements, IR, and 13C NMR, and also with the rate values of authentic terpolymers of 4-hydroxystyrene, t-butyl acrylate, and acrylic acid, which had been prepared from an ESCAP copolymer.

Section: Deprotection and Dissolution Behavior Of Escap (Uviihs) Resistmentioning

confidence: 99%

“…The dissolution inhibition effect of onium salt acid generators has been investigated in terms of their interaction with the phenolic OH group by 13C NMR. In addition, the dissolution behavior of the Shipley UVIIHS resist [4], built on IBM's ESCAP platform [5], is described in detail.…”

Section: Introductionmentioning

confidence: 99%

Dissolution Kinetics and PAG Interaction of Phenolic Resins in Chemically Amplified Resists.

Alexander

Breyta

1997

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“…The exceptionally high thermal and hydrolytic stability of the high activation energy ESCAP resist provides developed images that are (Figure 15) in contrast to all other deep UV resists in which a phenolic OH functionality is generated for aqueous base development. The ester-carboxylic acid conversion provides much higher dissolution differentiation (developer contrast) and a very large dissolution rate (30,000 A/sec in 0.26 N TMAH developer, for example) in the highly exposed areas (Figure 15) [82,83]. The high exposed dissolution rate and contrast once achieved has allowed their adjustment according to specific applications (nested line/space, contact holes, isolated lines, etc.)…”

Section: Progress and Current Statusmentioning

confidence: 99%

Evolution and Progress of Deep UV Resist Materials.

1998

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It has been almost thirty years since the first deep UV exposure was carried out and almost twenty five years since the term "deep UV lithography" was coined. Although resist systems classified as "chemical amplification resists" are the workhorse for the 248 nm deep UV lithography, the resist materials have evolved significantly in the realm of deep UV lithography as well as within the boundary of chemical amplification. This paper describes the evolution and progress of the deep UV (248-193 nm) positive resist materials that have occurred in the last quarter century.

“…Thus, the key step in the development of the environmentally stable chemical amplification positive resist ESCAP was identification of a robust resist resin [11][12][13]17,18]. Copolymers of 4-hydroxystyrene (HOST) with t-butyl (meth)acrylate (Scheme I) have extraordinary thermal stability with the onset of thermal deprotection observed at 180 °C ( Figure 2) [1 [1][2][3][4][5][6][7][8][9][10][11][12][13]17,18].…”

Section: Design Conceptmentioning

confidence: 99%

“…However, full implementation of deep UV lithography in device manufacturing would still require more fundamental built-in stabilization mechanisms. The newer deep UV Received May 7, 1996 Accepted June 17, 1996 557 positive resist systems currently available on the commercial market are much more environmentally stable due to reduction of either free volume [1 [1][2][3][4][5][6][7][8][9][10][11][12][13] or activation energy of deprotection [14,15].…”

Section: Introductionmentioning

confidence: 99%

Lithographic Feasibility of ESCAP Beyond Quarter Micron.

Breyta

Conley

et al. 1996

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A production-worthy deep UV resist system built on the ESCAP platform is described. The resist consists of a thermally and hydrolytically stable resin and acid generator and thus can be heated at high temperatures for free volume reduction, which provides stabilization toward airborne base contamination. The film densification in conjunction with the use of a bulky acid reduces acid diffusion during postexposure bake, contributing to high lithographic performance. Robust 0.25 µm process latitudes have been demonstrated. Furthermore, the resist has produced excellent 175 nm line/space images with a depth-of-focus of 0.3 p m on a KrF excimer laser stepper with a numerical aperture of 0.60, indicating that the resist allows the use of the current exposure tool in the early 1 Gbit generation.