International Business Machines Corporation

Seungbae Park

Sanjeev Balwant Sathe

David V Caletka

Voya Rista Markovich

Eric A Johnson

Aleksander Zubelewicz

Peter A Moschak

A chip module having a chip with a flexible multilayer redistribution thin film attached thereto for connection to a substrate. The thin film acts as both a redistribution medium with multiple layers of redistribution metallurgy for chip power and signals and as a compliant medium to relieve stresses caused by thermal expansion mismatch between chip and substrate. Modules comprising chip and thin film may be fabricated at the chip or wafer level. The upper surface of the thin film has an array of pads matching the array of pads on the chip or wafer while the lower surface has pads matching those of the substrate. The multilayer thin film is first formed on a temporary substrate and then the chip is attached to the thin film before release from the temporary substrate. After release, the module is ready for mounting to the second level packaging substrate, such as a chip carrier or PCB. Where the multilayer thin film is formed directly on a wafer, the wafer is then diced to form the module.

Wafer scale thin film package

A method and article of fabrication is described featuring a solder layer having a serpentine, interrupted, or interdigitated boundary. The non-planar design of the boundary layer increases the fatigue life of the solder joint by limiting the damage caused by micro-cracking. This irregularity of the solder boundary constrains the propagation of cracks by creating obstacles along the crack path, redirecting the crack away from the intermetallic layer, or by increasing the path along which the crack propagates.

Solder interconnect techniques

A chip carrier constituted of an organic laminate which incorporates structure compensating for thermal deformation of the carrier. Moreover, disclosed is a method of counteracting the thermal deformations encountered by chip carriers, especially during solder reflow, which is predicated on the uniformly, equidistant positioning of metal-plated through-holes (PTH) formed in the chip carrier relative to contact pads. A plurality of plated through-holes (PTH) are positioned equidistantly relative to contact (BGA) pads on a surface of a substrate which is constituted of an organic laminate material, so as to be able to control both in-plane and out-of-plane thermal deformations in the chip carrier material which may be occasioned in a solder reflow furnace or oven.

Thermal deformation management for chip carriers

A heat spreading cap is placed over a chip or integrated circuit. The cap is shaped or sized to provide a distinct heat spreading and/or stiffness characteristic that differs as it extends into different regions of the module. The areas of differing stiffness or CTE reduce the warpage (or bending) of the module, thereby reducing the overall stress in the BGA.

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Fishkill, NY, United States of America

Seungbae Park