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Molded Cavity Over Optical Device

IP.com Disclosure Number: IPCOM000013079D
Original Publication Date: 2001-Apr-26
Included in the Prior Art Database: 2003-Jun-12

Publishing Venue

IBM

Abstract

Disclosed is a molded cavity design that eliminates the presence of air bubbles in the clear molding compound material over the critical light sensitive area of optical devices. Encapsulation with clear molding compound materials is a newly developed specialty of the well established transfer molding process of electronic IC devices. Traditionally, in the manufacturing of light responsive circuit packages such as CCDs, clear glass lids were used to seal plastic premolded packages to allow the transmission of visual light signals to the device. As an alternative to the glass lid and to the premolded package, a one step manufacturing operation, namely the transfer molding of a clear molding compound, greatly simplifies the whole bond and assembly process. In order to allow proper light transmission to the device, there should be no defects such as air bubbles in the clear molding compound material over the device’s light sensitive area. A solution to eliminate the air bubbles is to create a depression in the clear molded package over this region. This downset shape in the clear molded package is formed by the specific top mold cavity design. It allows the air bubbles to concentrate on the higher peripheral areas, thus not affecting the light transmission. 1