Low-cost large area processing using small area substrates-a novel multitiled palletization concept for MCM-D thin film process

Abstract

Multichip module-deposited (MCM-D) has been the solution for integrated high density packaging due to its superior line resolution and higher inputs/outputs (I/O) density compared to MCM-C and multichip module-laminate (MCM-L) technologies. However the consumer demand for high performance products at reduced costs is ever increasing, and this trend is expected to continue in the 21st Century. In order to find a low-cost solution for future MCM-D packaging, a novel palletization process which incorporates several tiles (alumina or silicon) on a large carrier glass (pallet) has been established in this study. The multitiling format provides simultaneous processing of several small tiles onto a re-usable CTE matched carrier glass. The tiles are attached to the glass with a low modulus adhesive that can be released at an elevated temperature (/spl sim/450/spl deg/C). The objective of this study is to develop a multitiling process for a 300 mm/spl times/300 mm area that is scalable up to 600 mm/spl times/600 mm format. There are several challenges in realization of the large area palletization approach, such as formulation and qualification of a high temperature reworkable adhesive and minimization of out-of-plane warpage of the tiled assembly. Finite element models for warpage and its validation by shadow moire measurement, formulation of a compliant adhesive for thermal stability up to 400/spl deg/C are reported in previous publications. This paper deals with (1) the validation of the palletization concept on a 300 mm x 300 mm glass with weight restriction below 3 lbs and thickness limitation to <6.25 mm, and (2) qualification of the formulated adhesive through a correlative study on high temperature detachability of the attached tiles, chemical compatibility of the adhesive with acids, bases, and less polar solvents, and interfacial shear strength at the lass/adhesive/tile joints. MCM-D thin film process on the tiled substrates is to be conducted by the member companies of the MCM-D Consortium.