Semiconductor Package Recesses for Warping Stress
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Solution Overview
Problem
Flip chip chip-scale packages (FcCSP) experience reliability issues due to substrate warping during temperature stress, leading to bond breakage, delamination of underfill and passivation layers, and mechanical stress on electrical connectors.
Innovation Solution
Incorporating underfill material and adhesives into recesses and openings on the substrate and lid, which increases mechanical coupling and support, and using a reinforcement component with recesses to absorb stress, thereby reducing the likelihood of failures caused by substrate warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If FcCSP packages are used to reduce package size, then area utilization is improved, but substrate warping occurs during temperature stress
Solution Approach 1:
The patent applies local quality by creating recesses at specific locations on the substrate and lid surfaces where underfill and adhesive materials are placed. This localized modification of the substrate structure provides targeted stress absorption zones without affecting the overall compact package design, thereby maintaining small area while improving warping resistance.
Solution Approach 2:
The patent uses composite materials by combining the substrate with underfill material and adhesive material in a multi-layer structure. The underfill material fills the recesses on the substrate, and the adhesive material fills recesses on the lid, creating a composite structure that absorbs thermal stress and prevents warping while maintaining the compact form factor.
2Strength
If underfill and adhesive materials are added to recesses, then mechanical coupling is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the bonding interface into discrete recesses rather than using continuous adhesive layers. The underfill material is segmented into specific recesses on the substrate, and the adhesive material is segmented into specific recesses on the lid, creating a modular structure that enhances mechanical coupling while controlling complexity through localized placement.
Solution Approach 2:
The patent uses porous materials by creating recesses (void spaces) in the substrate and lid that are filled with underfill and adhesive materials. This porous structure increases the surface area for bonding and provides mechanical interlocking, thereby improving mechanical coupling strength while the recesses are integrated into the manufacturing process.
3Reliability
If reinforcement components with recesses are used, then stress absorption is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the recesses in the substrate and lid during the manufacturing process before final assembly. The recesses are pre-created in specific locations, and the underfill and adhesive materials are then placed into these pre-formed recesses, which simplifies the overall manufacturing process compared to attempting to add stress absorption features after assembly.
Data Source
AI summary
An embodiment is a structure. The structure comprises a substrate, a chip, and a reinforcement component. The substrate has a first surface, and the first surface comprises depressions. The chip is over and attached to the first surface of the substrate. The reinforcement component is over a first area of the first surface of the substrate. The first area is not under the chip. The reinforcement component has a portion disposed in at least some of the depressions in the first area.