P‐66: Wet Chemical Metallization for High‐End Flat Panel Display Manufacturing

Abstract

Recently the use of Copper as a conductor material for Thin Film Transistor (TFT) structures has received increasing attention in the Flat Panel Display industry [1,2]. Since sputtering of thick Cu layers has serious disadvantages Flat Panel Display (FPD) manufacturers are considering wet chemical Cu deposition as a viable process alternative. Depending on the required film properties like conductivity and surface roughness either electroless or electrolytical Copper deposition can be applied.

Hybrid Method for Metallization of Glass Interposers

“…[4][5][6][7][8]13,14,16,17,19,27,30,31 The silane solution was made in ethanol to facilitate penetration into small diameter holes. The silane treated surface was baked to hydrolyze the silane to improve its adhesion to the glass and to remove excess volatile material.…”

“…These include mechanical techniques (grit blasting, abrasive grinding) and chemical methods (etching with acidic fluoride solutions) or combinations of the two. 4,10,11 Both of these approaches can be somewhat effective, but they have limitations manifested by the inability to affect the holes and by the difficulty of handling thin glass substrates used for interposers. Another variation on the mechanical interlocking approach is roughening by application of a discontinuous photo mask on the glass followed by acid fluoride etching to produce a pattern of recessed and raised regions.…”

“…2,3 Copper is the preferred conductor due to its low resistivity. [4][5][6][7] However, in order to accommodate Cu circuitry, a barrier layer must be added between the Cu and silicon to prevent diffusion of Cu into the silicon and to avoid signal degradation. The latter concern relates especially to high frequency signals associated with high processing speeds.…”

“…The latter concern relates especially to high frequency signals associated with high processing speeds. [1][2][3][4] Glass on the other hand is an excellent electrical insulator, does not have a problem with Cu diffusion into it, and does not require a barrier layer. It is dimensionally stable, less expensive, and more easily processed than Si.…”

P‐72: Invar Fe‐Ni Alloy Metallization by Electroless Plating for TFTs

“…Cu produced by the vacuum evaporation method exhibits significant stress and poor adhesion to glass substrates or insulating layers such as SiO 2 , and SiNx. To overcome this issue, several methods have been reported that Ni films as an intermediate layer by electroless plating were deposited, and then Cu electrodes were formed on this layer [2][3][4].…”