Browse Prior Art Database

Surface Activation of Dielectrics for Electroless Plating

IP.com Disclosure Number: IPCOM000119707D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 138K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+4]

Abstract

Disclosed are several techniques that allow for selective surface modification to provide activation sites for electroless plating using laser ablation, photo exposure, spin coating of metal-organic links, and "loaded" polymers.

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Surface Activation of Dielectrics for Electroless Plating

      Disclosed are several techniques that allow for selective
surface modification to provide activation sites for electroless
plating using laser ablation, photo exposure, spin coating of
metal-organic links, and "loaded" polymers.

      The techniques utilize precision micromachining and microscopic
layer by layer removal of material with precise depth control, as
well as flash heating and annealing of very thin layers, which is
achievable with excimer lasers. Depending on the gas mixture in the
laser head, excimer lasers can be operated at four different
wavelengths: 193 nm, 248 nm, 308 nm and 351 nm.  The excimer lasers
can produce variable energy densities, and variable repetition rates,
thus allowing control of etch rates in various materials as a
function of fluence (energy density), wavelength and repetition rate.
By choosing the correct fluence, coupled with a fixed number of
pulses, precise control is obtained of material removal rate.

      Depicted in Fig. I is a multi-level dielectric consisting of a
polyimide "loaded" with palladium acetylacetonate and a normal
polyimide level.  Excimer laser ablation, i.e., at 248 nm, through a
mask, opens a via in level 2 and penetrates slightly into level 1,
providing a selective surface modification and a seeding layer of Pd
to initiate electroless plating of copper, as shown in Fig. II. Fig.
III-a shows two levels of polyimide sandwiched between a...