Tantalum and chromium adhesion to polyimide. Part 2. Peel and locus of failure analyses
- CF4 etch followed by Ar sputter yielded the strongest bond to the PI.
- Suggest that failure may be within the PI (cohesive), not between the PI and metal (adhesive).
Tantalum, tantalum nitride, and chromium adhesion to polyimide: effect of annealing ambient on adhesion
- The peel adhesion at T-0 (initial) shows the following order: TaNx∼ TaN < Ta∼ Cr, with all samples failing in apparently virgin PI.
- After ten thermal cycles to 400°C
- in forming gas the peel adhesion showed the following trend: TaNx < TaN∼ Ta ∼ Cr,
- whereas if the annealing was done in N2 the order changed to TaNx∼ TaN « Ta < Cr.
- The peel locus of failure was
- always in the apparently virgin PI in the Cr/PI samples,
- while the Ta/PI samples failed in the modified PI,
- and the TaN/PI and TaNx/PI samples failed between the Ta-nitride and the Cu peel backing film after thermal cycling.
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