Pre-molded Substrate for Hollow Semiconductor Device Moisture Protection
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Solution Overview
Problem
Conventional hollow type semiconductor devices with resin frames are prone to moisture infiltration, leading to corrosion and bonding failures due to the permeability of the resin frame, which compromises the reliability of the semiconductor device.
Innovation Solution
A pre-molded substrate design with a resin sealing body and non-moisture permeable frame-shaped wiring and walls is used, where the inner and outer leads, frame-shaped wiring, and first frame-shaped wall are embedded in the resin, with only their exposed surfaces accessible, and a sealing plate is bonded to create a hollow sealing body that minimizes moisture exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin frame body is used to surround the hollow portion, then the device structure is simple and easy to manufacture, but moisture easily permeates the thin resin frame body, increasing moisture reaching the semiconductor element surface
Solution Approach 1:
The frame body is divided into a resin frame body and a separate waterproof frame body made of non-moisture permeable material. The waterproof frame body is positioned inside the resin frame body to specifically address moisture protection, while the resin frame body provides structural support and ease of manufacture. This segmentation allows each component to fulfill its specific function optimally.
Solution Approach 2:
The device employs a composite structure combining resin material and non-moisture permeable material (such as metal or ceramic) in the frame body. The resin portion provides manufacturing ease and structural form, while the non-moisture permeable portion provides moisture barrier functionality. This composite approach resolves the contradiction between ease of manufacture and reliability.
2Ease of manufacture
If the frame body is made of resin material, then manufacturing is simplified, but moisture permeation causes corrosion and bonding failure, reducing device reliability
Solution Approach 1:
The waterproof frame body acts as an intermediary barrier between the external environment and the semiconductor element. It is positioned between the resin frame body and the semiconductor element to specifically block moisture infiltration paths, preventing moisture from reaching critical components while allowing the resin frame body to maintain its manufacturing advantages.
Solution Approach 2:
Instead of making the entire frame body non-moisture permeable (which would complicate manufacturing), the waterproof frame body is strategically placed only in areas where moisture protection is most critical - specifically surrounding the semiconductor element and electrical connections. This local application of moisture barrier properties maintains ease of manufacture while effectively addressing moisture infiltration.
3Measurement precision
If a hollow structure is adopted to reduce resin stress, then precision is improved, but moisture reaches the hollow portion more easily, causing deterioration
Solution Approach 1:
The hollow structure is segmented into an inner waterproof cavity and an outer resin structure. The waterproof frame body lines the inner cavity to specifically protect against moisture, while the outer resin frame body maintains the hollow structure's stress-relieving benefits. This segmentation allows the hollow structure to provide precision improvement while the waterproof layer prevents reliability degradation.
Solution Approach 2:
A thin waterproof frame body is used to line the hollow portion, providing effective moisture protection with minimal thickness. This thin film approach maintains the hollow structure's mechanical properties and stress-relieving function while adding the necessary moisture barrier to prevent deterioration of the semiconductor element.
Data Source
AI summary
A hollow type semiconductor device has a pre-molded substrate (15) in which an element mounting portion, top surfaces of inner leads (2), and a top surface of frame-shaped wiring (7) are exposed on a first surface of a resin sealing body (6), and back surfaces of outer leads (3) and a back surface of a first frame-shaped wall (8) are exposed on a back surface of the resin sealing body (6). A hollow sealing body (14) including a second frame-shaped wall (9) and a sealing plate (4) is provided on the pre-molded substrate (15). The second frame-shaped wall (9) and the sealing plate (4) enclose a hollow portion (13) in which a semiconductor element (1) is kept.