Interposer Adhesion Hole Structure for POP Delamination Mitigation
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Solution Overview
Problem
Conventional package-on-package (POP) devices suffer from delamination due to poor adhesion between the silicon die, mold, and substrate interposer, particularly at weak interfaces such as between the mold and interposer solder resist (SR) surface.
Innovation Solution
The proposed solution involves increasing the contact area for adhesion between the mold and the interposer by adding vertical contact surfaces. This is achieved by forming SR posts and post landings on the interposer, creating adhesion holes to expose their side surfaces, and filling these holes with mold material, thereby establishing direct contact between the mold and the interposer surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional POP structure is used, then device integration is achieved, but poor adhesion between silicon die, mold and substrate interposer causes delamination
Solution Approach 1:
The patent transitions from a conventional planar interface between mold and interposer to a three-dimensional structure with vertical adhesion holes. These holes expose side surfaces of SR posts and post landings, creating additional vertical contact area between the mold and interposer components, thereby enhancing adhesion through dimensional expansion.
Solution Approach 2:
The patent segments the interposer structure into distinct components: SR (solder resist) posts and post landings. By creating adhesion holes that expose the side surfaces of these segmented components, the patent increases the total contact area between the mold and interposer, improving adhesion through structural segmentation.
2Reliability
If contact area between mold and interposer is increased, then adhesion is enhanced, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the adhesion hole structure: it serves as both an adhesive bonding interface and an electrical connection pathway through the SR posts and post landings. This consolidation achieves enhanced adhesion without proportionally increasing structural complexity.
Data Source
AI summary
Disclosed are devices in which a die, such as a system-on-chip (SoC) die is attached to an interposer with a mold. Unlike convention devices, the contact area for adhesion is increased by providing vertical surfaces in addition to lateral surfaces for attachment. In so doing, possibility of delamination is decreased significantly.