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Conformal LGA PTH structure having Via In Pad , partial hard Ni /Au , Copper opposite to LGA side-- CITC performance of robust structure & Use thereof

IP.com Disclosure Number: IPCOM000016285D
Original Publication Date: 2002-Oct-04
Included in the Prior Art Database: 2003-Jun-21

Publishing Venue

IBM

Abstract

Conformal LGA PTH structure having Via In Pad , partial hard Ni /Au , Copper opposite to LGA side-- CITC performance of robust structure Use thereof Copper thickness on Plated thru hole (PTH) is very critical. Current induced thermal Cycling (CITC) data suggest that PTH reliability exposure exists when there is less than 0.7 mil copper thickness is present . Such PTHs , bearing galvanic etch potential conditions, upon thermal exposure cracks (see below). fails CITC below 10 cycles. Higher the copper thickness better the CITC performance. CITC DATA : 1