Techniques and Tools for Optical Lithography

Waldo, Whit

doi:10.1016/b978-0-8155-1281-3.50010-5

Cited by 1 publication

(1 citation statement)

References 220 publications

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“…A phase-shifting mask has a transparent phase-shifting layer covering adjacent apertures so that the light coming from one of the feature is delayed so that it arrives 180 degree out of phase. The two diffracted beams will cancel and desired dark area between images will be obtained [3].…”

Section: Introductionmentioning

confidence: 99%

Laser assisted focused-ion-beam-induced deposition of copper

Funatsu

1996

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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As the minimum feature size becomes on the order of submicron dimensions, techniques to directly repair VLSI circuits and x-ray masks, techniques for so-called "microsurgery", are increasingly important. Focused ion beam (FIB) techniques have been commercially used to deposit conductors and insulators and remove materials in a localized area on substrates. Copper, which is a candidate future conductor material in VLSI circuits due to its low resistivity and high electromigration resistance, has been deposited from the organometallic complex, Cu(hfac)TMVS, using 25 keV gallium ions from liquid ion source. Earlier work has shown that substrate heating can lead to FIB-induced deposition of high conductivity Cu lines. In this work, use of a laser for localized heating for FIB-induced deposition has been investigated as an alternative to heating of the entire substrate. For laser-assisted FIB-induced deposition, a "high power" :semiconductor laser, of wavelength 977 nm and output power ranging continuously from 0 to 1.2 W, was used. The laser was focused onto a thermally oxidized Si substrate, and its spot area is estimated to be 5.90x10 -5 cm 2 , which gives the maximum intensity of 2.0x10 4 W/cm 2 . Cu(hfac)TMVS has no absorption in the gas phase at 977 nm. As a result, for films deposited using this laser, the dependencies of the growth rate and resistivity on the estimated substrate temperature are in good agreement with those of films deposited using conventional resistance heating. The growth rate ranges from 2.0 to 4.3 A/s, depending on the laser power. A small decline in the growth rate in the relatively low laser power regime was observed. At higher laser powers, the growth rate is significantly increased. The lowest resistivity lines, 3 gQ-cm (close to the resistivity of bulk copper, 1.7 gQ-cm), has been achieved when deposited at 1.1 W of laser power. At this laser power, the substrate temperature is estimated to be 120 °C. The smallest line width, 0.8 gm, has been achieved when deposited without using the laser. The deposited lines become slightly wider for higher laser powers, causing the aspect ratio to be smaller. When deposited at high temperature, the deposited film becomes coarse and granular. Laser-assisted, FIB-induced deposition has been demonstrated as a means of 'writing high conductivity submicron Cu lines.

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Section: Introductionmentioning

confidence: 99%

Laser assisted focused-ion-beam-induced deposition of copper

Funatsu

1996

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

show abstract

Techniques and Tools for Optical Lithography

Cited by 1 publication

References 220 publications

Laser assisted focused-ion-beam-induced deposition of copper

Laser assisted focused-ion-beam-induced deposition of copper

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