Impact of BARC on SEM shrinkage of ArF resist

Abstract

The shrinkage of resist pattern during in-line SEM measurement has been argued and studied as one of the problems unsettled for manufacturing with ArF photolithography. Many of attempts to solve this problem have focused their attentions on the improvement of resist and inspection equipment. We bring up BARC (bottom anti-reflective coating) as a new impact factor on SEM shrinkage of resist. Practically, although the same resist was employed, our shrinkage tests gave the results depending on the kind of BARC. Feature size and depth of focus also affect SEM shrinkage of resist. Effect of reflectivity on SEM shrinkage was evaluated by changing thickness of BARCs and resultantly was somewhat significant. In this paper, the BARC-dependent results of SEM shrinkage are analyzed and discussed to provide a possibility that BARC may have another function of reducing SEM shrinkage.

Photoresist cross-sectional shape change caused by scanning electron microscope-induced shrinkage

“…Some recent studies on the distribution of incident electrons discuss that the electrons scattered from spaces around a given pattern into the pattern's sidewall should be taken into consideration along with the directly-irradiated electrons. [16][17][18] Some studies on the effect of elastic deformation mentioned its impact on the pattern shape change. 19,20 Nevertheless, their experimental verifications were limited because they were based on measurements taken using an atomic force microscope (AFM) or a SEM.…”

Photoresist Shrinkage Caused by Single-Line Scan of Electron Beam

“…Therefore, photoresist shrinkage caused by BSEs distributes wider than the electron-scattering range. Although the contribution of back-scattered electrons has been previously investigated 14,24,25) in terms of its effects on the deformation of the cross section of a photoresist line, their lateral distribution has not been investigated.…”

“…Studies on photoresist shrinkage so far have focused on the microscopic interaction between an electron and photoresist molecules [10][11][12] or on the macroscopic tendency of shrinkage due to uniform irradiation. [13][14][15][16][17] In contrast, our approach can provide information on how the microscopic volume-reduction caused by electron-molecule interactions is integrated into macroscopic pattern deformation.…”

Precise Cross-Sectional Measurement of Photoresist Shrinkage Caused by Electron Beam Irradiation

“…Most studies on photoresist shrinkage so far have mainly focused on the phenomenology of linewidth slimming [10][11][12][13][14][15][16][17] or the microscopic mechanisms of local volume reduction in the second step, namely, the interaction between an electron and photoresist molecules. [18][19][20] Some recent studies examined the effects of electrons scattered from spaces between patterns [21][22][23][24] and elastic deformation on pattern shape. 25,26) Nevertheless, the experimental verifications of such effects were limited because they were based on measurements with an atomic force microscope (AFM) or an SEM.…”