Semiconductor manufacturing technology is currently undergoing a transformation from immersion
photolithography to double patterning or EUV technology. The resultant resist dimensional size and height shrinks will
require improved pattern transfer techniques and materials.
Underlayer (UL) processes which include chemical vapor deposition (CVD) and spin-on application play a very
important role in various chip manufacturing integration schemes. A pattern wiggling problem during substrate etch has
arisen as a critical issue when pattern dimensions shrink. CVD processes have shown better pattern transfer performance
than spin-on processes but at higher cost and process complexity along with difficulty in obtaining planarization and
good gap fill. Thus spin-on process development has received increased attention recently as an attractive alternative to
In this work we focus on elucidating the mechanism of UL wiggling and have synthesized materials that address
several hypothesized mechanisms of failure: hydrogen content, modulus, film density, charge control unit type and
thermal resistance. UL materials with high thermal resistance additionally provide the ability to expand the applicability
of spin-on approaches. Material properties and wiggle failure test results will be discussed.
Extreme ultraviolet (EUV) lithography is one of the most promising technologies for achieving 22nm HP lithography
and beyond. EUV resist is required to improve resolution limit down to less than 20nm hp. To achieve such a
performance, innovative materials' development is necessary under ultra-thin resist film condition for preventing line
collapse. In addition, more refined etching processes compatible with ultra-thin resist film are needed.
In this study, we will report our several approaches for both materials and processes towards forming less than 20nm HP
pattern under ultra-thin film condition. We will also introduce our tri-layer system formed with combination of Si-ARC
stack and organic hard mask (OHM) stack for refined etching process.
Extreme ultraviolet (EUV) lithography is one of the most promising candidates for next generation
lithography (NGL) that can print 22nmhp and beyond. In order to implement EUV technology, resist is one of
the critical items that require significant improvement in overall performance. In order to achieve these
improvements, many research groups are developing new materials such as molecular glass (MG) polymer
bound photo-acid generator (PAG) high quantum yield PAG, sensitizer and high absorption resin.
In this study, we focused on innovative PAG materials and correlated PAG acid diffusion length to
lithography performance. As a result, new resist designs with improved resolution, LWR,
sensitivity are reported.
Double patterning is one of the most promising techniques for sub-30nm half pitch device manufacturing. Several
techniques such as dual-trench process (litho-etch-litho-etch: LELE) and dual-line process (litho-litho-etch : LLE) have
been reported. Between them, the dual-line process attracts a great deal of attention due to its higher throughput. The key
issue in the dual-line process is preventing damage of the first resist pattern during the second lithography process. As a
solution, we have developed a process to alleviate this issue using a chemical material called "freezing agent." More
recently, we have further simplified the process by developing a simple freezing technique called "self-freezing" or
"thermal-freezing." The "self-freezing resist" material can accomplish the freezing process by applying only one bake to
the resulting first pattern. In addition, our self-freezing resist also has added water shedding properties to meet non-topcoat
(non-TC) immersion resist requirements, which further simplifies the process and materials.
In this study, imaging results of Non-TC self-freezing resist including critical dimension uniformity, defectivity and
processing properties of the resulting patterns is shown.
In order to achieve targeted resist performance for EUV in practical applications, we have developed new materials such
as molecular glass (MG), PAG, and acid amplifiers (AA). Protected NORIA, a molecular glass, was examined for
extending resolution limits. The resist with protected NORIA showed 22 nm hp resolutions under EUV exposure. PAG
acid diffusion effect on LWR was also investigated. It was found that acid diffusion control was one of the most
important factors for LWR improvement. To improve sensitivity, application of AA (acid amplifier) was investigated.
The resist with AA gained 25% sensitivity improvement over the original formulation. Elemental technologies for major progress of EUV resist were made.
It has been found that 193nm immersion lithography technology can achieve smaller patterns without any
modification to the technology infrastructure of existing state-of-the-art 193nm dry lithography. This has made 193nm
immersion lithography a promising technology for mass production processes. Recently, scanning speed of the exposure
stage has been increasing in order to achieve high throughput for mass production. At present, the adoption of a topcoat
is one of the promising candidates for this high speed scanning process. On the other hand, the demand for a non-topcoat
process is being pursued from a C.O.O. (cost of ownership) point of view but there are still issues being revealed and
concerns to be solved. In this report, feasibility of a comprehensive process for high scanning ArF immersion lithography was discussed. As for the topcoat process, a high receding contact angle topcoat, such as TC-A (JSR), is proving to be a good candidate for mass production using high scanning speed immersion lithography. TC-A has a similar defectivity and lithographic performance to TCX041 (JSR). On the other hand, the feasibility of a non-topcoat process was also investigated. CD uniformity, defectivity and lithography performance of AIM5120JN and AIM5570JN (JSR) data indicate that the non-topcoat process can be adopted for mass production process. An immersion cluster comprised of a high volume production immersion exposure tool, S610C (NIKON) having 1.3 NA and CLEAN TRACK<sup>TM</sup> LITHIUS<sup>TM</sup> i+ (TEL) track system were used in this study.
The 193 nm immersion lithography has been increasingly applied to the semiconductor device mass production. Topcoat
material would be used in many such cases. Topcoat film can maximize the scan speed during immersion exposure step
and also prevent small molecules from leaching out of resist film. However, the use of the topcoat material in the mass
production affects productivity including throughput and chemical cost. To manage this problem, we attempted to
improve topcoat coating process to reduce the topcoat material consumption. Using JSR NFC TCX041, the developersoluble
type topcoat material, as a model material, we examined a new coating process which introduces a pre-wet
treatment using a solvent which was chosen to be appropriate for this purpose. With this new coating process, we
achieved 65 percent (or more) reduction of the topcoat material consumption compared with the current standard coating
process (dynamic coating). From the result of film surface observations and leaching tests, it was learned that the topcoat
film properties by the new coating process are equivalent to those by the standard coating process. The process
performance after development also indicated good results.