Multiple Patterning

• Involves decomposing the design across multiple masks to allow the printing of tighter pitches

• 38-nm features with 193-nm light water immersion lithography is the limitation with the current lithographic process

• Multiple Patterning is a technique used in the lithographic process that can create the features less than 38nm at advanced process nodes

• Multiple patterning basically changing the value of K1 in the Critical Dimension equation

Double Patterning

• Double patterning counters the effects of diffraction in optical lithography
• Diffraction effects makes it difficult to produce accurately defined deep sub-micron patterns using existing lighting sources and conventional masks
• Diffraction effects makes sharp corners and edges become blur, and some small features on the mask won’t appear on the wafer at all
• Double patterning is expensive because it uses two masks to define a layer that was defined with one at previous process nodes