Advanpack Solutions Pte Ltd.

St Assembly Test Services Inc.

Tie Wang

Il Kwon Shim

Sheila Marie L Alvarez

Virgil Cotoco Ararao

Colin Chun Sing Lum

Ping Miao

Chun Sing Colin Lum

Yixin Chew

A method for fabricating a semiconductor package with a substrate in a strip format is provided. Semiconductor devices are attached in a strip format to the substrate, and a thermal interface material is applied to the semiconductor devices. A flat panel heat spreader is attached to each semiconductor device. The semiconductor devices are encapsulated with open encapsulation, leaving the surface of the flat panel heat spreader opposite the substrate externally exposed. Individual semiconductor packages are then singulated from the strip format.

Strip-fabricated flip chip in package and flip chip in system heat spreader assemblies and fabrication methods therefor

A method for joining a semiconductor integrated circuit (IC) chip in a flip chip configuration, via pillar bump, to solderable metal contact pads, leads or circuit lines on the ciruitized surface of a chip carrier, as well as the resulting chip package, are disclosed. The semiconductor device is attached to the substrate via no flow underfill under thermal compression bonding. Integration of this structure and assembly method enables to incorporate low coefficient of thermal expansion (CTE) no flow underfill and achieve high assembly yield, especially for lead free bumps. The present invention provides a solution for a flip chip package with fine pitch, high pin count and lead free requirements.

Method for fabricating a flip chip package with pillar bump and no flow underfill

An improved underfill adhesive encapsulant with fluxing activities containing an epoxy resin or a mixture of epoxy resin. An anhydride is used as the curing agent to harden the epoxy resin. A hydroxyl-containing fluxing precursor compound is added to the encapsulant composition to react with the anhydride curing agent to produce an active fluxing agent under typical reflow conditions. The use of a fluxing precursor gives improved reliability compared to conventional fluxing agents used in existing no-flow underfill encapsulants. A suitable catalyst such as imidazole, imidazole derivative or metal acetylacetonate is provided in the present encapsulant at concentrations that give good curing kinetics. A thermoplastic is optionally included to allow the cured encapsulant to be reworked.

Fluxing adhesive

In a no-flow underfill process , a substrate is heated to an elevated temperature prior to dispensing underfill thereon. The underfill flows more readily over mask portions and conductors on the substrate , filling in spaces between the conductors and the masking portions , thereby preventing air from being trapped thereabout. In addition, when a bumped die is heated during placement on the substrate with the underfill therebetween, the underfill flows around bumps more readily thereby preventing air from being trapped thereabout. The result is a flip chip semiconductor package having a lower void density.

Growing community of inventors

Singapore, Singapore

Tie Wang