Semiconductor Package Molding Structure to Prevent Pad Flash
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Solution Overview
Problem
The semiconductor industry faces challenges in achieving high package yield due to issues such as mold flash obscuring contact pads and substrate deformation caused by clamping forces during the molding process in System-in-Package (SiP) technologies, leading to poor electrical interconnections and device failures.
Innovation Solution
A method and apparatus that include a stress absorbing layer on the substrate and a mold with a recess adjacent to the cavity to prevent mold flash and absorb clamping-induced stress, ensuring the contact pads remain unobstructed and undamaged, thereby improving package yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mold is used to encapsulate the electronic component during the molding process, then the electronic component is protected and integrated into the package, but mold flash occurs that obscures the contact pads and causes poor electrical interconnections
Solution Approach 1:
The harmful mold flash is extracted and isolated from the contact pad area by introducing a protective structure (such as a shield or barrier) that removes the contaminant from the critical electrical connection zone, preventing flash obscuration of contact pads
Solution Approach 2:
An intermediary protective structure is introduced between the mold cavity and the contact pads to prevent direct contact between mold flash and the contact pad area, serving as a mediator that blocks harmful substances while allowing the molding process to proceed
2Reliability
If clamping forces are applied during the molding process to secure the package, then the encapsulation is formed, but substrate deformation occurs that leads to device failures
Solution Approach 1:
A stress-absorbing structure is pre-installed on the substrate before the molding process to cushion and distribute the clamping forces that will be applied during encapsulation, preventing direct transmission of harmful forces to the substrate and electronic components
Solution Approach 2:
The mechanical properties of the substrate are modified by adding a stress-absorbing layer with different elasticity or compliance characteristics, changing the overall mechanical response of the substrate to clamping forces and preventing deformation-induced failures
3Adaptability or versatility
If multiple components are integrated into a single package using SiP technology, then functionality is increased, but package yield decreases due to cumulative defects
Solution Approach 1:
The stress and complexity inherent in multi-component integration are converted into benefits by designing a package structure with built-in stress management features that actually improve reliability, turning the potential harm of cumulative defects into an opportunity for enhanced package robustness through careful mechanical design
Data Source
AI summary
A method for forming a semiconductor device is provided. The method include: providing a package including: a substrate; a stress absorbing layer disposed on a top surface of the substrate; an electronic component mounted on the top surface of substrate; and a first contact pad disposed on the top surface of the substrate and exposed from the stress absorbing layer; providing a mold including: a first cavity exposed from a bottom surface of the mold; and a recess formed adjacent to the first cavity; engaging the mold and the package with the first cavity over the electronic component and the recess between the electronic component and the first contact pad; and injecting encapsulation material into the first cavity to form an encapsulant over the electronic component.