Lithographic application of diamond-like carbon films

• Published in: Thin solid films 1995-01, Vol.254 (1-2), p.92-95
• Main Authors: Seth, Jayshree, Babu, S.V., Ralchenko, V.G., Kononenko, T.V., Ageev, V.P., Strelnitsky, V.E.
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon; Electronics; Exact sciences and technology; Laser irradiation; Microelectronic fabrication (materials and surfaces technology); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/0040-6090(94)06263-K

A combined laser-plasma-etching technique has been investigated for utilizing diamond-like carbon (DLC) films as resists in lithography. The technique is based on the selective enhancement of O2 plasma etch rates of DLC films due to graphitization in the regions exposed to excimer laser radiation. The patterns delineated in the DLC resist by laser and oxygen plasma exposure have been transferred into the underlying silicon substrate by fluorocarbon reactive ion etching with (RIE) the patterned DLC film acting as an in situ mask. Using this scheme, space-line patterns 5 μm wide were made on silicon substrates to demonstrate the feasibility of the proposed laser-RIE process for semiconductor patterning. The laser fluence required for graphitization is ~100 mJ cm−2, the O2 plasma etch rates of the graphitized regions are higher by a factor of ~3.5 and the contrast (γ) for the DLC resist is 1.1. The use of DLC for submicron resolution warrants further investigation.