High-selectivity magnetically enhanced reactive ion etching of boron nitride films

Abstract

. ABSTRACTOxygen and tetrafluorocarbon magnetically enhanced reactive ion etching (MERlE) of plasma chemical vapor deposited (CVD) boron nitride (BN) and silicon boron nitride (SiBN) was studied for both blanket and submicron patterned films. The relative etch selectivities of the BN and SiBN to oxide (Si02) and nitride (SiN) were determined. In general, oxygen rich 02/CF4 MERlE produce very high etch selectivity results while maintaining vertical etch profiles.This etch process expands the potential for use of BN/SiBN in fabrication of sub-half micron devices. . INTRODUCTIONFor sub-half micron microelectronic fabrication, plasma CVD BN and SiBN have been considered for fabrication schemes. Highly stable plasma CVD BN films can be deposited using diborane/ammonia'7 or borazine8 sources.The appropriate etch and polish selectivities are desirable for patterning and building contact and wiring levels in microelectronic devices. High polish selectivities of BN films to Si02 and SiN have been reported recently9, and ae advantageous when fabricating sub half micron devices that require very small critical dimensions for enhanced performance. Reactive ion etching of BN films using CF4/H2 have been reported"7 as well using fluorine-rich CF4/02 plasma'°'11. However, the high selectivity etching of BN and SiBN insulators over commonly used Si02 and SiN dielectrics has not been previously reported.In this paper, we present high selectivity MERlE of BN and SiBN films using an oxygen-'rich fluorine based, single wafer process.'2 The study examined the etch selectivity of BN/SiBN to Si02 and SiN using various CF4/(1O-90%)02 flow ratios. The effects of pressure, power, magnetic field and CF4/02 flow ratio in the oxygen-rich regime were also explored. Using this high selectivity etch process, patterned BN and SiBN films were etched to build submicron tungsten wiring for microelectronic devices. 3. EXPERIMENTAL 3.1 Tool configuration Blanket and masked BN and SiBN films were etched in an automated single O819413625/94/$600 SPIE Vol. 2091 / 197 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/21/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

Dielectric Barrier, Etch Stop, and Metal Capping Materials for State of the Art and beyond Metal Interconnects

“…434,436 For this reason, B 2 O 3 is likely unsuitable for low-k interconnect applications. Boron nitride (BN) does not exhibit the same extreme hygroscopic behavior as B 2 O 3 and has been investigated for numerous electronic applications as a gate dielectric, 437 ILD, 434 ES, 438 DB, 439 HM, 440 polish stop, 441 and UV photo-detector / light emitting diode.…”