Photodefinable Epoxycyclohexyl Polyhedral Oligomeric Silsesquioxane

Abstract

A photodefinable dielectric was developed using epoxycyclohexyl polyhedral oligomeric silsesquioxanes (POSS) and a photocatalyst. POSS is a hybrid organic/inorganic dielectric which has favorable mechanical and chemical stability for use as a permanent dielectric in microfabrication. Sharp, 10 lm wide features were formed from POSS using 365 nm radiation. The optical contrast was 1.51. POSS films were thermally stable to 350°C and demonstrated chemical stability in a variety of solvents and oxidants. The polymer film had an elastic modulus of 5.3 GPa and a hardness of 0.64 GPa. The POSS had high etch selectivity compared with organic films for pattern transfer.

Electroless Deposition of Copper on Organic and Inorganic Substrates Using a Sn/Ag Catalyst

“…Previously, dichromate has been used to oxidize surface films and etch epoxy boards to improve the chemical bonding of electroless metal to the surface. 21 The chromic acid etch investigated here consisted of 40 mL DI water, 75 mL sulfuric acid, and 1.3 g potassium dichromate, and was maintained at 90 • C. The chromic acid etch led to the deposition of an adherent, elecroless copper layer on the POSS substrate; however, the results were sometimes difficult to reproduce. It was found that a similar solution without the potassium dichromate, containing only the sulfuric acid (i.e.…”

“…POSS film formulations and processing were completed as described previously. 21 The POSS samples were spin-coated onto the FR-4 boards and then soft-baked on a hotplate at 85 o C for 5 min to remove the solvent from the polymer film. A 1 kW Hg-Xe lamp with a broad band filter (350 to 380 nm wavelength) was used for exposure with an optimal dose of 250 mJ/cm 2 .…”

Polyimide foam-like microstructures: technology and mechanical properties

“…Metz et al proposed PI-based thin microfluidic channels by the lamination technique [11], but PI adhesive bonding suffers from film non-uniformity and void generation problems [12]. Finally, physical techniques for manufacturing microair structures, including the use of sacrificial materials, have been extensively studied by the group of Kohl [13][14][15][16][17][18][19][20][21]. Based on this concept, single-layer microchannels and micro-scaled sealed cavities in PI have been reported by several authors [13,16,22].…”

“…Poly(propylene, ethylene, cyclohexane) carbonates [14,16,20,22], dendritic hyperbranched polymers (HBP) [23], polynorborenes (PNB) [13,16,19,21], tetracyclododecenes (TCD) [18,19] have been used for this approach.…”

“…They can be structured by electron beam lithography [24], dry etch [14,22] or conventional lithography methods [15,19]. Most of those materials, however, are not compatible with PI-overcoat processes because of a high decomposition temperature, and a high solubility of the sacrificial material in the PI's solvent.…”