Spin-Coating Polyimide Film on Hydrogenated DLC Film Surface Prepared by Ion Beam Deposition Method

Abstract

The present work describes the hybrid layers consisting of 1-mm-thick hydrogenated diamond-like carbon (DLCH) film deposited by ion beam deposition (IBD) method as the bottom layer and spin coating polyimide (PI) film at a thickness of 6 mm as the top layer. Optical microscopy shows that all DLCH film, PI film and PI/DLCH film have smooth surface and are free from cracks or wrinkles. Water contact angle measurement shows that the annealed DLCH film has the higher relative adhesive tension and adhesive work than that of PI film. Raman spectra show that the DLCH film can avoid severe graphitization & degradation at 300 C during annealing treatment, and FTIR spectra also exhibit that the PI film will reach 95% imidization during the curing step at 300 C. PI film can act on DLCH film as the stress buffer. This is demonstrate from warpage measurement showing that top PI film with tensile stress can partially reduce the compressive stress over bottom DLCH film with 6.7% warpage reduction. The electrical resistivity of PI/DLCH/Si is similar to that of PI/Si is resulted from the PI passivation effect.

Correlation between <B>sp</B><SUP><B>2</B></SUP><B>/sp</B><SUP><B>3</B></SUP> Ratio or Hydrogen Content and Water Contact Angle in Hydrogenated DLC Film

“…40,41) Figure 5 shows that the water contact angles of DLCH film are as a function of annealed temperature, and the water contact angle for as-deposited state, 300 C, 350 C and 400 C is 37.0 , 52.6 , 55.6 and 62.0 , respectively. 42) This trend shows the higher the annealed temperature, the larger the water contact angle (i.e. the more hydrophobic of DLCH film), which might result from the thermal treatment leading to graphitization for DLCH film.…”

Niobium-Containing DLC Coatings on Various Substrates for Strain Gauges

“…Several investigations of the interface of DLC and polyimide stated its good adhesion properties [13,14]. Presumably, a low-mismatch interface and high-energetic covalent bonds between the carbon of the polymer and the carbon of the coating are causal therefor.…”