Developer effect on the negative tone development process under low NILS conditions

Modeling the impact of shrinkage effects on photoresist development

“…Dissolution rates at lower exposure areas have an impact on the defect characteristics of the resist profile. 14 The thermodynamic characteristics of the photoresist material influence the dissolution rate due to the fact that the chemical developer depends on how fast the solvent molecule penetrates the polymer network. 15 The solubility characteristics of a particular polymer depends on its chemical structure and it tends to dissolve in solvents with similar solubility parameters and polarities.…”

“…The volume loss causes strains within the resist bulk, which can be represented by the expression in Eq. (14), which approximates to the trace of the strain tensor. Figure 9 shows the individual strain components of the strain tensor for the test case considered in this section.…”

ArF photoresist polymers with nitrogen or sulfone moieties for negative tone development process

“…[1][2][3][4] NTD process can exhibit increased optical contrast due to the use of bright mask to largely covered layer such as contact hole (CH) and narrow trench layer with ArF immersion exposure, whereas it has been found that positive tone development (PTD) process with dark mask do not provide such contrast. 5 Polarity change type photoresists with organic solvent developers have been studied as a candidate for ArF NTD, because large contrast in dissolution rate can be obtained by the polarity change of resist polymers when de-protection reaction occurs.…”

“…5 Polarity change type photoresists with organic solvent developers have been studied as a candidate for ArF NTD, because large contrast in dissolution rate can be obtained by the polarity change of resist polymers when de-protection reaction occurs. 4 Although cross-linking type negative photoresists stand as the competitor of NTD, lack of contrast and swelling of the resists generally cause detrimental effects on the lithographic performance. 6 In the NTD process, it is important to optimize the combination of photoresist polymers and developers, because it affects the dissolution rate of polymers and lithographic patterns.…”

“…6 In the NTD process, it is important to optimize the combination of photoresist polymers and developers, because it affects the dissolution rate of polymers and lithographic patterns. 1,4,7 Another advantage of the NTD process is that the conventional polyacrylate photoresist system can be applied to the process without further altering the polymers. 6 However, as there are certain differences between the NTD and conventional PTD processes, the polymer structures and the component of the photoresists should be investigated thoroughly.…”