Method for the use of press molds to create cavity features in thermoset dielectrics

Method for the use of press molds to create cavity features in thermoset dielectrics

Disclosed is a method for the use of press molds to create cavity features in thermoset dielectrics. Benefits include improved functionality, improved ease of manufacturing, and improved reliability.

Background

        � � � � � To achieve the thinner packages required for small, thin applications, the stack height of substrate packages must be reduced.

� � � � � Conventionally, pads and die reside above the dielectric layer (see Figures 1 and 2). The use of solder resist defines the pad size.

General description

� � � � � The disclosed method is the creation of cavities in substrates through custom design press molds in thermoset dielectric lamination during the substrate build-up processes. Cavities in the dielectric are created for the pads and die to reside (see Figures 3 and 4).

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� � � � � The key elements of the disclosed method include:

•        � � � � Substrate stack-up reduction with wirebond pads, bump pads, and a die residing in the cavity

•        � � � � Custom design of a press mold, pending substrate layout designs

•        � � � � No change to the overall current dielectric final thickness post lamination

•        � � � � Solder resist not required for this application because of nickel and gold plated pads

Advantages

        � � � � � The disclosed method provides advantages, including:

•        � � � � Improved functionality due to the improvement of the substrate and package overall stack-up height

•        � � � �...