1.  Technical Field
A photoresist polymer for a top-surface imaging process by silylation (TIPS), and a photoresist composition containing the same.  In particular, a photoresist polymer which can perform a silylation process by selectively providing protecting group in an exposed region to generate a hydroxyl group, and by reacting the hydroxyl group with a silylation agent, and a photoresist composition containing the same. 
2.  Description of the Background Art
Thin layer imaging technologies such as TIPS are effective patterning processes for photolithography using a wavelength below 193 nm and optical lithography using an extreme ultraviolet (EUV) wavelength (e.g., 13 nm). 
Some of the known limitations of the photolithography include substrate""s influence on the light (e.g., reflection, scattering, diffraction, etc.),  notching, standing wave effect, pattern collapse, non-uniformity of a critical dimension (CD), isolated and grouped bias (IG bias) and the like.  In TIPS, a shallow exposure is performed which forms a latent image by diffusion of acids that is generated in the exposed region.  The exposed region is then selectively silylated with a silylating agent.  The silylated region serves as a mask, and the non-silylated region is dry-etched by 02 plasma.  Thus, TIPS requires photoresist compositions having a high energy absorption coefficient and process conditions that have high selectivity in etching non-silylated regions during O2 plasma treatment. 
TIPS is rarely influenced by substrates and topology.  In addition, TIPS is less sensitive to transparency, adhesiveness and etching selection ratio of the photoresist composition.  TIPS also has a much wider depth of focus in high resolution than a single layer resist (SLR).  Thus, in some aspects, TIPS has more advantages than a general resist patterning process. 
In addition, compared with a wet development of SLR, the dry development process of TIPS can be applied to a thick resist process in a high aspect ratio without causing a pattern to collapse.  This advantage is useful on a substrate having a relatively low etching selection ratio, such as an oxide or metal.  As a result, TIPS is recognized as an alternative to SLR. 
A photoresist (PR) polymer for top-surface imaging process by silylation (TIPS) using a light source such as KrF, ArF, VUW, EUV and E-beam, and process for preparing thereof are disclosed. 
A photoresist composition comprising the PR polymers described above is also disclosed. 
A semiconductor element produced by using the disclosed photoresist composition is also disclosed.