Institute of Microelectronics

Leong Tee Koh

Rakesh Kumar

Pang Dow Foo

Joseph Zhifeng Xie

Marokkey Raphael Sajan

Tsun-Lung Alex Cheng

The current invention teaches the use of e-beam patterning techniques for forming contact and via holes of diameter less than about 0.15 microns down to 0.05 microns. E-beam lithography has higher resolution (down to 30-50 nanometers) as compared to 130-150 nanometer when using deep ultra violet (DUV) photolithography patterning techniques. In addition the invention uses a mix and match approach by employing a conventional I-line, or deep UV, resist to form the trench pattern and e-beam lithography tools to form the contact and vial hole patterns. A simplified process scheme is developed where contact/via holes are formed first on solvent developable e-beam resist and the trench pattern is formed on aqueous developable photoresist coated on top of the e-beam resist.

Bi-layer resist process for dual damascene

Under the first embodiment of the invention, a three layer composite layer of insulation is deposited. The trench is etched into this composite layer of insulation followed by a hard bake. The via etch is performed, completing the formation of the dual damascene profile. The created dual damascene profile is transferred into the underlying substrate; the layer of photoresist is removed. Under the second embodiment of the invention, a two layer composite layer of insulation is deposited over a semiconductor surface. The trench is etched into this composite layer of insulation. A layer of positive photoresist is deposited over the second layer of cross-linked negative resist and masked for the via etch. The via etch is performed, the created dual damascene profile is transferred into the underlying substrate. The removal of the layers of patterned photoresist completes the formation of the dual damascene structure.

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Johor Bahru, Malaysia

Leong Tee Koh