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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
Document File: 1 page(s) / 26K

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

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Molded Cavity Over Optical Device

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