Surface Mount Module Diffusion Barrier Moisture Ingress
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Solution Overview
Problem
Surface-mount power semiconductor devices are susceptible to moisture and gas ingress, leading to delamination, corrosion, and mechanical failures due to increased vapor pressure and exposure to corrosive environments, which affects their reliability and longevity.
Innovation Solution
A diffusion barrier coating is applied to the surface-mount package to reduce moisture and gas ingress, using a low-permeability layer that can be applied during manufacturing, ensuring the solderability of interconnections and providing enhanced reliability against environmental degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard POL package manufacturing process is used without additional barrier layers, then the manufacturing process is simple and cost-effective, but the package is susceptible to moisture and gas ingress leading to delamination, corrosion, and mechanical failures
Solution Approach 1:
The patent applies the nesting principle by integrating the diffusion barrier layer within the existing package structure, specifically between the organic dielectric material and the power semiconductor device. This nested approach adds protective functionality without significantly altering the overall package architecture, thereby improving reliability against moisture and gas ingress while maintaining relatively simple package structure complexity.
Solution Approach 2:
The patent employs composite materials by combining the organic dielectric material with a diffusion barrier layer to create a hybrid structure. This composite approach leverages the electrical insulation properties of the organic dielectric while adding the moisture and gas blocking properties of the diffusion barrier layer, thus improving reliability without requiring a complete redesign of the package structure.
2Duration of action of stationary object
If the package materials absorb moisture during storage, then long term storage is possible, but vapor pressure increases at soldering temperatures causing delamination and pop-corning
Solution Approach 1:
The patent applies preliminary action by incorporating the diffusion barrier layer during the manufacturing process, before the package undergoes storage and subsequent soldering operations. This pre-established barrier prevents moisture absorption during storage and subsequently blocks moisture from generating excessive vapor pressure during soldering, thereby preventing delamination and pop-corning while enabling long-term storage.
Solution Approach 2:
The diffusion barrier layer acts as an intermediary between the organic dielectric material and the external environment. It mediates the interaction by allowing the package to be stored for extended periods while blocking moisture ingress that would otherwise lead to vapor pressure buildup and reliability issues during subsequent processing.
3Temperature
If oxygen ingress occurs at elevated temperatures, then storage is possible, but adhesion between POL metal and Kapton degrades rapidly
Solution Approach 1:
The diffusion barrier layer serves as an intermediary that blocks oxygen ingress between the POL metal and Kapton layers during elevated temperature storage. By preventing oxygen from reaching the interface between these materials, the barrier maintains adhesion strength even when the package is stored at high temperatures, thus resolving the contradiction between operating temperature capability and adhesion strength retention.
Solution Approach 2:
The patent applies the extraction principle by removing oxygen from the environment at the critical interface between POL metal and Kapton through the diffusion barrier layer. This extraction of the harmful oxygen element prevents oxidative degradation and maintains adhesion strength during elevated temperature storage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The diffusion barrier coating significantly reduces moisture and gas absorption, enhancing the reliability of the surface-mount package by preventing delamination and corrosion, while maintaining the solderability of interconnections, thus improving the long-term performance and lifespan of the semiconductor devices.
Implementation Method 1
a diffusion barrier coating configured to reduce the ingress of moisture and gases from a surrounding environment into the surface-mount structure
Data Source
Figure 1
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AI summary
A surface-mount package structure (10) for reducing the ingress of moisture and gases thereto is disclosed. The surface-mount structure (10) includes a sub-module (14) having a dielectric layer (30), semiconductor devices (12) attached to the dielectric layer (30), a first level interconnect structure (28) electrically coupled to the semiconductor devices (12), and a second level I/O connection (16) electrically coupled to the first level interconnect (38) and formed on the dielectric layer (30), with the second level I/O connection (16) configured to connect the sub-module (14) to an external circuit. The semiconductor devices (12) of the sub-module (14) are attached to a substrate structure (18), with a dielectric material (26) positioned between the dielectric layer (30) and the substrate structure (18) to fill in gaps in the surface-mount structure (10). A diffusion barrier layer (28) is applied over the sub-module (14), adjacent the first and second level I/O connections (38,16), and extends down to the substrate structure (18) to reduce the ingress of moisture and gases from a surrounding environment into the surface-mount structure (10).