Conference Paper

Evaluation of Cu capping alternatives for polyimide-Cu MCM-D

IBM Microelectron., Hopewell Junction, NY
DOI: 10.1109/ECTC.2001.927977 Conference: Electronic Components and Technology Conference, 2001. Proceedings., 51st
Source: IEEE Xplore

ABSTRACT Among the 3 types of polyimide (PI) systems, pre-imidized,
polyamic ester and polyamic acid, the latter has been shown to react
with Cu surfaces when it is spun coated. This paper reviews Cu-polyimide
adhesion and diffusion data and present various wet process alternatives
to minimize Cu diffusion into poly(biphenyl dianhydride-p-phenylene
diamine) (BPDA-PDA) polyamic acid precursor. Two different process
options were investigated: a precoat or adhesion promoters (A1100, AP420
and benzotriazole) prior to the polyamic acid apply, and an additive
(Tetrazole or BTA) formulated in the PAA solution. The 5 processes were
compared with respect to adhesion, capacitance, dielectric constant and
reliability. Only the BTA formulation had adhesion problems which were
attributed to the A1100 precoat used. A1100 as a precoat was further
evaluated on various copper surfaces and curing environments. All
proposed solutions performed well when used on a MCM-D/C module which
was used to extract electrical parametrics and was further subjected to
reliability testing

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