Vapor phase reactions in polymerization plasma for divinylsiloxane-bis-benzocyclobutene film deposition

Abstract

Vapor phase reactions in plasma polymerization of divinylsiloxane-bis-benzocyclobutene (DVS-BCB) low-k film depositions on 300mm wafers were studied using mass spectrometry, in situ Fourier transform infrared, and a surface wave probe. Polymerization via Diels-Alder cycloaddition reaction was identified by the detection of the benzocyclohexene group. Hydrogen addition and methyl group desorption were also detected in DVS-BCB monomer and related large molecules. The dielectric constant k of plasma polymerized DVS-BCB with a plasma source power range up to 250W was close to ∼2.7 of thermally polymerized DVS-BCB, and increased gradually over 250W. The electron density at 250W was about 1.5×1010cm−3. The increase of the k value at higher power was explained by the decrease of both large molecular species via multistep dissociation and incorporation of silica components into the polymer. It was found that the reduction of electron density as well as precursor residence time is important for the plasma polymerization process to prevent the excess dissociation of the precursor.

Time-resolved curling-probe measurements of electron density in high frequency pulsed DC discharges

“…However, this method also suffers from metal impurities that are released within a relatively short lifetime of a tungsten filament that is used in this method. Plasma absorption probe (also referred to as a surface wave probe) can be used for measuring the plasma electron density [3][4][5] and electron temperature [6][7][8][9][10][11][12] without metal contaminations, even in the situation wherein the plasma deposits a non-conducting layer on the probe. However, this technique exhibits weak measurement accuracy for high pressure (>100 Pa) and low electron density (< 5 × 10 9 cm −3 ) plasmas.…”

Characterization of oxygen and nitrogen rapid thermal annealing processes for ultra-low-k SiCOH films

“…5 Therefore, it is important to develop low-k films with improved mechanical strength. [6][7][8] In this work, ultra-low-k films with k values of 2.4 are deposited by plasma-enhanced chemical vapor deposition (PECVD) with decamethylcyclopentasiloxane (DMCPSO, C 10 H 30 O 5 Si 5 ) and cyclohexane (CHex, C 6 H 12 ). The k values are reduced further to <2 by removing thermally unstable cyclohexane fragments from the films, which generates porosity in the films.…”

Opto-Curling Probe for Simultaneous Monitoring of Optical Emission and Electron Density in Reactive Plasmas

“…In order to exclude metal impurity release from the probe, a plasma absorption probe (later called surface wave probe) has been developed, which enables the space-resolved measurements of electron density [4][5][6] and electron temperature 7) in reactive plasma. Subsequently, several different types of plasma absorption probe have been reported.…”