10-06-2017, 06:44 AM
Introduction to Lithography for Nanometer VLSI Manufacturing
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Optical Proximity Correction (OPC)
Optical proximity correction (OPC) is a photolithography enhancement techniques commonly used to compensate the mask pattern for image errors due to diffraction or process effects[2].
Design for Manufacturability (DFM)
A design methodologyincludes a set of techniquesto modify the design of ICs in order to improve:
Functional yield, parametric yield, reliability
Techniques includes:
Substituting higher yield cellswhere permitted by timing, power, and routability.
Changing the spacingand widthof the interconnect wires, where possible
Optimizing the amount of redundancyin internal memories.
Substituting fault tolerant(redundant) viasin a design where possible.
Massively Parallel Mask-less Lithography (MPML2)
E-beam lithography is capable of sub-20 nmpatterning.
E-beam direct write technique eliminate the costof mask fabrication ( 2M USD.) and correction ( 1 week).
Direct write technique is capable of patterning more complex patterns(e.g. Fresnel zone plate).
Challenges:
Integrate as many as possible beams into the system.
Design an effective writing strategyto maximize system throughput.
Electron-resist interaction(proximity effect) correction.
Design a data transfersystem to process huge data at one time.