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1. Technical Field 

Photoresist polymers and photoresist compositions con› taining the same are disclosed that can improve profile of a photoresist pattern, without the need for any dummy pat› terns and which improve etch resistance during pattern formation. 

2. Description of the Related Art 

As manufacturing processes of semiconductor devices become more complicated and the degree of integration increases, methods for forming fine patterns are needed. Since it is difficult to obtain a fine pattern with conventional photolithography using KrF (248 nm), photolithography using far-infrared light source such as ArF (193 nm) has been developed. However, photoresist materials that have been used in ArF photolithography are more difficult to use than conventional photoresist materials. Specifically, as the critical dimension CD has been decreased by the high integration of semiconductor devices, the aspect ratio of a pattern is increased which can cause collapse the photoresist pattern 12 on the semiconductor substrate 11 as shown in FIG. 1. 

There are many processes for forming layers of semicon› ductors. As the size of a pattern becomes smaller, a pattern in the outer region of a field or a block becomes remarkably smaller because the pattern in the outer region receives a relatively larger amount of light energy in comparison with the inside of the field of the block where patterns are arranged more uniformly and densely. 

In order to prevent the outer portions of the pattern from being reduced in size, the amount of energy or an exposure condition of lens has been regulated. However, this conven› tional method does not solve the problem. 

In addition, problems arise when the margins of DOF (Depth of Focus) and EL (Energy Latitude) become smaller as the pattern becomes smaller. However, these problems carmot be solved by using the change of exposure condi› tions. Also, it is difficult to secure etching resistance because the thickness of the photoresist film is reduced to prevent pattern collapse. 

Disclosed herein are photoresist polymers and photoresist compositions comprising the same that can improve a profile of an outer region of a field or a block which receives a relatively large amount of light when a pattern is formed. The disclosed photoresist polymers and compositions also enhance etching resistance. 

Disclosed herein is a method for forming a phtoresist pattern using the disclosed photoresist composition. Also, disclosed herein is a semiconductor device obtained by the disclosed method. 

For a more complete understanding of this disclosure, reference should be made to the following detailed descrip› tion and accompanying drawings, wherein: 

FIG. 1 is a diagram illustrating a pattern formed using a conventional photoresist polymer; and 

# PHOTORESIST POLYMER AND PHOTORESIST COMPOSITION CONTAINING THE SAME 

## SUMMARY OF THE DISCLOSURE 

## BRIEF DESCRIPTION OF THE DRAWINGS 

## BACKGROUND 

FIG. 2 is a diagram illustrating a process for obtaining an improved pattern profile of an outer region of a field using a disclosed photoresist polymer. 

## DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS 

A disclosed photoresist polymer comprises a polymeriza› tion repeating unit represented by Formula 1: 1 ° Formula 1 

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wherein Ri, R$_{2 }$ and R$_{3 }$ are individually Hor CH$_{3}$ ; R$_{4 }$ is linear or branched C$_{3}$-C$_{10 }$ alkylene group; R$_{5}$ , R$_{6 }$ and R$_{7 }$ are individually C$_{1}$-C$_{3 }$ alkoxy group; R$_{8}$ , R$_{9 }$ and R$_{10 }$are individually H or CH$_{3}$ ; R$_{11 }$ is linear or branched C$_{1}$-C$_{3 }$ alkyl group; R$_{12 }$ 1s hydrogen; and, a ratio of a:b:c:d falls within a range of 20-40 mo! %:20-35 mo! %:15-25 mo! %:15-20 mo!%. The polymer has a molecular weight ranging from 1,000 to 10,000, preferably from 1,500 to 4,000. Preferably, the polymerization repeating unit represented by Formula 1 is represented by Formula la: Formula la 

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In the disclosed photoresist polymer, a monomer consti› tuting the repeating unit "a" has a long chain by introducing linear or branched C$_{3}$-C$_{10 }$ alkylene structure to prevent steric hindrance between end groups, thereby facilitating polymerization of polymers. Also, the monomer of the repeating unit "a" contains a large percentage of silicon and carbon to improve hardness of photoresist. Additionally, increase of etching resistance due to introduction of a silicon group allows a photoresist film having a lower thickness to serve as an etching mask in an etching process using a CF 4 plasma gas. 

