m8ta
You are not authenticated, login.
text: sort by
tags: modified
type: chronology
{1248}
hide / / print
ref: -0 tags: polyimide adhesion silver surface treatment adhesion delamination date: 10-04-2013 01:30 gmt revision:8 [7] [6] [5] [4] [3] [2] [head]

Improved polyimide/metal adhesion by chemical modification approaches

  • Suggest fuming sulfuric acid (H2S04) + Ag2SO4 for 30s as the most effective treatment.
  • 1 minute in 1M KOH also effective.
  • Silver was magnetron-sputtered on; peel test performed with tape.

IEEE-4936772 (pdf) Studies of adhesion of metal films to polyimide

  • Suggest Ar / O2 plasma treatment of surface to increase Cr/Cu adhesion (mechanical effect?)
  • Used two different polyimides: one derived from (BPDA‐PDA) polyamic acid, and pyromellitic dianhydride‐4,4’‐oxydianiline (PMDA‐ODA).

IEEE-670747 (pdf) Adhesion evaluation of adhesiveless metal/polyimide substrate for MCM and high density packaging

  • Adhesion of Cr / polyimide interface is degraded significantly upon exposure to high temperature and humidity environment due to the hydrolysis of polyimide.
  • There is also some worry of Cu diffusion into the polyimide.
  • All used a Cr tie layer, 200A thick (20nm).
  • Deposited photoresist, electroplated copper, then etched to define pattern.
  • Testing performed at 121C 100% RH, +15psi. (tough!)

On polyimide-polyimide interlayer adhesion: Diffusion and self-adhesion of the polyimide PMDA-ODA (1987)

  • Diffusion occurred during the curing process of the second layer and was controlled by the cure schedule.
  • It was found that a large diffusion distance, at least 200 nm, was required to obtain a bond whose strength was equal to that of bulk material.
  • Good protocol:
    • Dry first layer at 80C for 30 minutes.
    • 150C (or lower?) bake of first layer. "as the polyamic acid imidizes (and the solvent is lost) its diffusive mobility decreases rapidly; very little diffusion occurs after the first few minutes of the second bake.
    • Spin coat second layer.
    • 400C second bake.
  • Ductility is increased for polyimide that has experienced a series of increasing cure temperatures.
  • In this context it is worth noting that the contour length of a PMDA-ODA of 30,000 molecular weight is about 130nm, a value very similar to the diffusion distances measured when T1 (first layer bake) was 150C.