Resist development to improve flare issue of EUV lithography

Irie, Makiko; Suzuki, Takahiro; Mimura, Takeyoshi; Iwai, Takeshi

doi:10.1117/12.771120

Cited by 10 publications

(10 citation statements)

References 2 publications

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“…The "thermal flow temperature" technique employed here was a modified version of that used by Irie and coworkers for measuring the glass-transition temperature of resist films on a substrate. 8 In this experiment, the patterned film was subjected to different temperatures and the temperature at which a 10% change in the critical dimension (CD) of the pattern after a bake time of 1 minute was denoted as the film glass-transition temperature. Thus, the study was split into two main thrusts: (1) determining the change in glass-transition temperature of the film for a specific …”

Section: Film Glass-transition Temperature As Observed By a Thermal-fmentioning

confidence: 99%

Elucidating the physiochemical and lithographic behavior of ultra-thin photoresist films

Sundaramoorthi

Younkin

Henderson

2009

Advances in Resist Materials and Processing Technology XXVI

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As resist feature sizes and film thicknesses continue to shrink in dimension, a number of resist feature size and film thickness dependent effects are being observed in the lithographic performance of high resolution photoresists. In order to understand these phenomena, a better understanding of the physiochemical behavior of complex multi-component organic resist thin films is needed. As a first step in that direction, a series of model photoresists were studied in an effort to begin to understand the thermophysical properties of such multi-component thin films. The influence of photoacid generator (PAG) loading and PAG chemistry on the glass transition behavior using the model photoresists was studied. A thermal flow experiment was used to characterize an "apparent glass transition temperature" of the resist thin films as a function of PAG type and loading. These results were compared to traditional glass transition measurements made on the same resist compositions using differential scanning calorimetry (DSC). The two methods, namely DSC and the thermal flow measurement, yielded very different results depending on the type of PAG used. Further studies using ToF SIMS to profile the distribution of PAG in the resist thin films revealed that the two PAGs focused on in this work, a triphenylsulfonium triflate (TPS.OTF) and a triphenylsulfonium nonaflate (TPS.ONF), exhibited very different distribution behavior in resist thin films. In the case of TPS.OTF, the PAG was observed to show a depletion region near the resistsubstrate interface while the TPS.ONF PAG was relatively homogeneously distributed in the resist thin films. In the case of TPS.ONF, it was also the resist system which showed very different thermophysical behavior when comparing the glass transition temperature measured using DSC to the thermal flow temperature measurement. This work points out the fact that component distribution and thin film effects must be carefully considered in interpreting and analyzing the behavior of multi-component thin films.

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Section: Film Glass-transition Temperature As Observed By a Thermal-fmentioning

confidence: 99%

Elucidating the physiochemical and lithographic behavior of ultra-thin photoresist films

Sundaramoorthi

Younkin

Henderson

2009

Advances in Resist Materials and Processing Technology XXVI

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“…As increasing PAG loading ratio, film Tg is getting lower due to a plasticizing effect induced by blended PAG molecules in the resist film. [14] So the samples in higher PAG loading ratio region should show lower Tg and longer acid diffusion length compared with those on lower region, resulting in worse LWR and ultimate resolution. The reason why LWR get worse would be the diffusion length might not match for the feature size in high loading region.…”

Section: Changing Pag Loading Ratiomentioning

confidence: 99%

Limitation of blend type of resist platform on EUV lithography

Hirayama

Kim

et al. 2012

SPIE Proceedings

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Chemically amplified resist (CAR) system is being widely used not only for 248 nm and 193 nm lithography but for Extreme Ultra Violet Lithography (EUVL).[1] And CAR system is based on blend resist platform which is formulated with polymer and photo-acid generator (PAG) independently. In EUVL to aim at 22 nm node and beyond, EUV resists are required to achieve much higher acid generation efficiency and overcome RLS (Resolution, Line edge roughness, Sensitivity) trade-off using some ideas such as increase in PAG concentration and film absorption coefficient, suppression of acid diffusion length and so on.[2-6] Increase in PAG loading ratio is a promising strategy to improve EUV resist performance,[7-10] however there must be upper limitation of PAG loading ratio on blend resist platform due to lowering film Tg induced by a plasticization effect of blended PAG. This plasticization effect of blended PAG would have another impact to increase acid diffusion length, resulting in low resolution and significant thickness loss, especially on ultra thin film condition. On the other hand, utilizing the PAG having bulky cation structure was beneficial in order to maintain dark loss (in other word, top loss) of the patterned features, however, this type of cation would show low quantum yield driven by the substituent on a cation structure, so that total performance such as ultimate resolution deteriorated. From these results, the bound resist platform which has PAG unit on polymer backbone as branch would be promising platform because of its potential advantages such as suppression of dark loss, no plasticization effect and control of acid diffusion.

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“…TF was determined as the temperature at which a CD shrink of 10% was observed as compared to a wafer without a post bake according to the same manner reported in previous paper. [9][10] Characteristics of the polymers are summarized in Table 1 For TF measurement, two different kinds of TF are investigated. The TF measured using the wafer where 170 nm hole feature is fabricated is Pre-TF.…”

Section: Preparation Of the Polymersmentioning

confidence: 99%

Characteristics of main chain decomposable star shaped polymer on EUV lithography

et al. 2010

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We prepared three different kinds of polymers. The first was the STAR polymers having various length of the arms connected to the single core which could be decomposed by the acid. The second was the Linear polymers based on p-hydroxystylene (HS) which was also used for the arms of the STAR polymer. The other was the non-decomposable STAR polymer which had a quite similar shape to the STAR polymer and of which core structure could not be decomposed.Using those materials, lithographic performance obtained using a Micro Exposure Tool (MET) was compared with thermal property, and it was found that STAR-9mer-H having the 9 HS unit arms provided best overall performance, 24 nm of ultimate resolution, 4.3 nm of line width roughness and 4.6x10 -8 mJ･nm 3 of Z factor on MET evaluation. In addition to this, the specific resist based on the STAR polymer could achieve 26 nm resolution with quite wider process window capability that the control resist consisting of partially protected poly(p-hydroxystyrene) on the Alpha Demo Tool evaluation with conventional illumination.

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Resist development to improve flare issue of EUV lithography

Cited by 10 publications

References 2 publications

Elucidating the physiochemical and lithographic behavior of ultra-thin photoresist films

Elucidating the physiochemical and lithographic behavior of ultra-thin photoresist films

Limitation of blend type of resist platform on EUV lithography

Characteristics of main chain decomposable star shaped polymer on EUV lithography

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