Patterning with Organized Molecules

Decades of progress in the semiconductor industry has led to lithographically printed dimensions that are small enough that the positions of individual molecules and the stochastic variation in the number of photons have a significant effect on the quality of photoresist patterns.These effects scale badly and will be more important as feature sizes continue to shrink.Selforganizing materials can provide regular patterns of molecules that have the potential to minimize stochastic effects.Some such reported materials are block copolymers,bottle brush polymers and DNA,all of which have been used as part of lithographic patterning.A key challenge for selforganizing materials is defect levels.The energy to rearrange has to be high enough that random defects aren’t created thermally but low enough that rearrangement into preferred domains can occur.All of the methods can generate accurate CDs based on the chemical composition of the material,but they all need some way to control the positions of the feature edges.There are methods for guiding the self-organization,but the final position is the sum of the guide pattern misalignment and the intrinsic alignment error of the self-organizing materials.Thus it can be worse than the positioning of the guide structures.Alignment and defect levels are thus two big challenges for manufacturing introduction of self-organizing materials.