MEMS Package Moisture Resistive Layer
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Solution Overview
Problem
Conventional MEMS package structures using organic polymer compounds as sealants and encapsulants fail to provide long-term moisture resistance, leading to compromised airtightness and operational reliability of microelectromechanical devices over time.
Innovation Solution
A package structure incorporating a moisture-resistant layer made of inorganic insulating materials like silica or silicon nitride, deposited using CVD or PVD techniques, is applied over an organic polymer encapsulant to enhance airtightness and moisture resistance, with a sealant connecting the chip and lid to further secure the MEMS device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic polymer compound is used as sealant or encapsulant, then ease of manufacture is improved, but moisture resistance deteriorates over time
Solution Approach 1:
The patent combines organic polymer encapsulant with inorganic moisture resistive layer to create a composite structure. The organic polymer provides ease of manufacture and basic sealing, while the inorganic layer adds superior moisture resistance. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The patent applies different material properties to different parts of the encapsulation system. The organic polymer is used for the bulk encapsulant where ease of manufacture is critical, while the inorganic moisture resistive layer is applied specifically on the surface where moisture resistance is most needed. This local differentiation resolves the contradiction between manufacturability and long-term reliability.
2Ease of manufacture
If organic polymer encapsulant is used, then ease of manufacture is improved, but airtightness deteriorates after long time
Solution Approach 1:
The patent creates a composite encapsulation system combining organic polymer with inorganic moisture resistive layer. The organic polymer provides easy manufacturing through dispensing, while the inorganic layer deposited by CVD or PVD provides stable, long-term airtightness that prevents degradation over time.
Solution Approach 2:
The inorganic moisture resistive layer acts as an intermediary barrier between the organic polymer encapsulant and the external environment. It mediates the interaction with moisture and maintains airtightness, protecting the organic polymer from degradation while preserving the ease of manufacture advantage.
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 combination of organic polymer encapsulants and inorganic moisture-resistant layers significantly improves the long-term airtightness and reliability of MEMS devices by preventing contamination and maintaining operational integrity.
Implementation Method 1
The moisture resistive layer is formed by chemical vapour deposition (CVD) or physical vapour deposition (PVD)
Implementation Method 2
The moisture resistive layer is formed by chemical vapour deposition (CVD) or physical vapour deposition (PVD)
Data Source
AI summary
A package structure including a chip, a lid, a substrate, a plurality of wires, an encapsulant, and a moisture resistive layer is provided. The chip has an active area where at least one MEMS device is disposed. The lid is covered on the chip, and the substrate is used to carry the chip and the lid. The plurality of wires is electrically connected between the substrate and the chip. The encapsulant is sealed around the lid and exposes an upper surface of the lid. The moisture resistive layer is covered on the encapsulant to enhance the airtightness and the moisture resistance of the encapsulant.