The Resolution Limit of the Resist Silylation Process in i-Line Lithography

Takehara, Daisuke; Ota, Tsuneo; Tanimoto, Keishi; Kawabata, Ryohei; Shibayama, Hikou

doi:10.1143/jjap.30.190

Cited by 6 publications

(3 citation statements)

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“…The photoresists (PR) are etched by plasma instead of wet development. 1 Usually, reactive ion etching (RIE) are used for PR etch processes. However, RIE etching processes have difficulties to improve critical dimension (CD) skews and micro-loading effects.…”

Section: Introductionmentioning

confidence: 99%

<title>ECR plasma and etch characterization of photoresist dry etch processes</title>

Cho

1992

SPIE Proceedings

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Photoresist dry etching processes by a down-stream type ECR plasma etcher were characterized. The etched photoresist profile and etch rates were obtained by scanning electron microscope (SEM) photographs and an optical thickness monitoring instrument, respectively. The mask used for PR etch tests has 1 urn pitched line & space patterns. It was found that C12 addition to 02 plasma can passivate PR side walls. The etch profiles of PR vary critically with the main coil current changes. The etch rate has maximum of 4800 A/mm and the etch uniformity has a minimum value of 5.4 %.The dc bias voltage (Vdc) variations are closely related to the etch profiles. Vdc decreases when PR etching is completed and substrates are exposed to the plasma. The wafers with different thin film materials induce different Vdc for a same process condition. The plasma properties were measured by a Langmuir probe. The N2 addition to 02 plasma were also tested. However, the critical effect of the main coil current was not found for the N2 processes. A model was formulated to explain the difference between Cl2 processes and N2 processes with an equivalent circuit method.

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Section: Introductionmentioning

confidence: 99%

<title>ECR plasma and etch characterization of photoresist dry etch processes</title>

Cho

1992

SPIE Proceedings

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“…The DESIRE process which is one of the surface imaging process is one of the most promising lithography techniques for the development for half or sub-half micron devices such as MM and 256Mbit DRAMs [4,5,6,7]. It is consisted of selective silylation, that is to say, which proceeds only in the exposed region near the surface of resist film, followed by drydevelopment process with utilizing the silylated layer as an etching mask.…”

Section: Introductionmentioning

confidence: 99%

<title>Study of relationship between silylated profile and resist profile through variation in the process condition and resist materials in the DESIRE process</title>

et al. 1992

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This paper describes the effect of process condition on the resist profile in the DESIRE process[1,21 ,which is one of the surface imaging process, has some advantages compared with conventional photo lithography process. In our previous study on the resist profile, it was indicated that pattern formation was strongly depended on the silylated layer and the degree of sidewall protection during dry-development [3]. Then, we studied the effect of sidewall protection under various process factors such as soft-bake, silylation, and various resist materials. From the results of the study, it was found that the degree of sidewall protection could be controlled by the process conditions, attributed to silylated profile and the degree of silylation. Clear tendency that silylated profile leaving a trail gave a vertical sidewall profile was observed. Furthermore, it was found that silicon dioxide was observed on the sidewall surface of resist pattern by Micro Auger Electron Spectroscopy. The silicon dioxide seems to act as an inhibiting layer for lateral etching during Oxygen RIE. We will also report the mechanism consideration of sidewall protection during dry-development. Consequently, through the whole process optimization, 0.3jim L/S resist pattern resolution and 1.4im wide focus range at 0.36prn L/S with a thickness 1.2tm are successfully obtained even in a single layer using i-line stepper with NA 0.50. INTRODUCTIONThe DESIRE process which is one of the surface imaging process is one of the most promising lithography techniques for the development for half or sub-half micron devices such as MM and 256Mbit DRAMs[4,5,6,7]. It is consisted of selective silylation, that is to say, which proceeds only in the exposed region near the surface of resist film, followed by drydevelopment process with utilizing the silylated layer as an etching mask. The resist profile, however, was strongly influenced by its silylated profile. In our previous study, it was found that silylated profile with having a thin shape and a gentle slope at the edge of it gave a vertical resist profile after dry-development. Furthermore, resist profile with vertical sidewall exhibited higher sidewall protection than that of undercut one[3,8}.In this study, we investigated the relation between final resist profile and silylated one obtained under various process conditions with also various resist materials. In order to elucidate these effects, we examined such process factors as soft-bake, silylation, and also resist materials. And through the analysis of the silylated region and resist sidewall, mechanism of sidewall protection was discussed.3. EXPERIMENTAL UJE(UCB-JSR Electronics) PLASMASK 200GC and 250G resists composed of novolak type resin, naphtoquinonediazide(NQD) compound and other additives, were spin-coated on a silicon wafer up to 1 .5itm thickness followed by softbake on a hot-plate at the temperature in the range of 90 to 120°C for 60s. Exposures were carried out by a NIKON g-line stepper with a 0.54 NA lens and a NIKON i-line stepper with a...

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“…For instance, the limitations of resolution in the DESIRE process [5], the methods of optimizing DESIRE process [6], mechanism of the DESIRE process [7,8], applications of mass production of ULSI[9, 1O,11], and only a few papers report the silylation kinetics [12,13]. For instance, the limitations of resolution in the DESIRE process [5], the methods of optimizing DESIRE process [6], mechanism of the DESIRE process [7,8], applications of mass production of ULSI[9, 1O,11], and only a few papers report the silylation kinetics [12,13].…”

Section: Introductionmentioning

confidence: 99%

<title>Effect of silylation condition on the silylated image in the DESIRE process</title>

Taira

Takahashi

Yanagihara

1991

Advances in Resist Technology and Processing VIII

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In recent years, there have been a lot of studies on surface imaging techniques in which the single layer lithography process is utilized. They have advantages of capability of high resolution, wide focus latitude, small critical dimension(CD) variation on topography, as well as their process simplicity compared with multilayer lithography process.The DESIRE[1,2] process, one of the surface imaging process, also has the same advantages.

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The Resolution Limit of the Resist Silylation Process in i-Line Lithography

Cited by 6 publications

References 0 publications

<title>ECR plasma and etch characterization of photoresist dry etch processes</title>

<title>ECR plasma and etch characterization of photoresist dry etch processes</title>

<title>Study of relationship between silylated profile and resist profile through variation in the process condition and resist materials in the DESIRE process</title>

<title>Effect of silylation condition on the silylated image in the DESIRE process</title>

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