Carbon rich hard mask underlayer (UL) material deposition has become inevitable process in all advanced lithography applications. UL processes which include chemical vapor deposition (CVD) and spin-on UL play a very important role for pattern transfer from patterned thin photoresist to the substrate. UL materials must satisfy several requirements, which have become more demanding with device shrinkage and increasing device complexity (FinFET, 3D integration). The most important properties of next generation UL materials are superior wiggle resistance, etch controllability, thermal resistance, planarization, and gap filling performance. In particular, planarization and gap fill properties of UL material for application on topo-patterned substrate are receiving much attention recently. CVD processes generally give better wiggle performance and thermal resistance, but poorer planarization and gap filling performance than spin-on UL processes. In addition, Cost of Ownership (CoO) of CVD process is higher than that of a spin-on UL process. Therefore spin-on organic hard mask (OHM) process has been investigated as an attractive alternative to CVD processing. In this paper, we focus on an investigation of key properties of spin-on UL materials for achieving good planarity and gap filling performance on topo-patterned substrate. Various material properties such as solution viscosity, glass transition temperature (Tg), and film shrinkage ratio were evaluated and correlations between these properties and planarization were discussed.
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.
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.
Double patterning is one of the most promising lithography techniques for sub-40nm half-pitch device
manufacturing. Several variations of double patterning processes have been reported by research groups, including a
dual-trench process (litho-etch-litho-etch) and a dual-line process (litho-litho-etch). Between these, the dual-line process
attracts the most attention because it is a simple process and achieves high throughput. However, there is concern that
the second lithography process damages the first lithography patterns in the dual-line process. Therefore, new
technology must be developed to keep the configuration of first lithography patterns during the second lithography step,
and to make this patterning process practical.
Recently, we succeeded in forming 32 nm half-pitch LS lithography patterns by the introduction of a new "freezing"
step. This step involves covering the first lithography pattern with a chemical freezing material to prevent damage by the
second lithography process. This process, the so called "litho-freezing-litho-etch" process, will achieve higher
throughput and lower cost compared to litho-etch-litho-etch.
In this study, the performance of this chemical freezing double patterning process is investigated for various
applications using a hyper NA immersion exposure tool. Imaging results including process window and etching results
of sub-30nm half-pitch LS and 40nm half-pitch CH with this freezing process are shown. Additionally, items such as
critical dimension uniformity and defect inspection using the freezing process were reviewed.
Double patterning based on existing ArF lithography technology is one of the most promising candidates for sub-40nm half-pitch devices. Several variation of double patterning processes have been reported by research groups, including a dual-trench process (litho-etch-litho-etch) and a dual-line process (litho-litho-etch). Between these, the dual-line process is attracting the most attention because it is a simple process that achieves high throughput. However, there is concern that the second lithographic process damages the first litho patterns in the dual-line process. Therefore, new technology must be developed to keep the configuration of first litho patterns during the second lithographic step for this patterning process to be practical.
Recently, we have succeeded in forming sub-40nm half-pitch litho patterns by the introduction of a new "freezing" step to this process. This step involves covering the first litho pattern with chemical freezing materials to prevent damage by the second litho pattern creating a dual-line process composed of litho-"freezing"-litho-etch processes. In this paper, the details of dual-line process including a "freezing" step are explained and sub-40nm half-pitch litho patterns by this process are shown.