Embedded Interconnect Board Cavity Structure for Warpage and Crack Control
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Solution Overview
Problem
Conventional resin laminate substrates and copper lead frame substrates face issues such as peeling, warpage, and cracking, which compromise the reliability and performance of high-performance semiconductor devices.
Innovation Solution
An interconnect board design featuring electrically conductive posts, a first conductive island, a stress-relief resin layer, a crack-inhibiting dielectric layer, and a circuitry layer, with the stress-relief resin layer laterally covering the posts and surrounding a cavity to minimize warpage and improve structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional resin laminate substrates are used, then manufacturing is simple, but the electroplated copper layer peels under stringent operational conditions
Solution Approach 1:
The patent uses a composite substrate structure combining resin laminate with a copper lead frame assembly. The lead frame provides a stable base for electroplated copper layers, preventing peeling while maintaining manufacturing feasibility. The composite structure integrates the advantages of both materials: the ease of resin laminate processing with the structural stability of metal lead frames.
2Reliability
If copper lead frame substrates are used, then thermal conductivity and electrical properties are excellent, but warpage and cracking occur
Solution Approach 1:
The patent applies local quality by positioning stress-relief resin layers specifically at critical stress concentration points around the cavity and conductive posts. This localized reinforcement provides structural support where needed most, preventing warpage and cracking in high-stress areas without compromising the overall electrical and thermal performance of the copper lead frame substrate.
Solution Approach 2:
The stress-relief resin layer acts as a pre-installed cushioning element that absorbs and distributes thermal and mechanical stresses before they can cause warpage or cracking. This preventive measure is built into the substrate structure during manufacturing, protecting against future thermal cycling and mechanical loading issues.
3Reliability
If multi-layer ceramic substrates are used, then electrical insulation and mechanical strength are excellent, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the essential functions of multi-layer ceramic substrates (electrical insulation and mechanical strength) and implements them through a simplified hybrid structure. The resin laminate provides the base substrate, the copper lead frame assembly provides structural integrity and electrical pathways, and the stress-relief resin layers provide the necessary insulation and stress management, eliminating the need for complex multi-layer ceramic stacking.
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 design alleviates warpage and enhances electrical and thermal performance, providing a reliable platform for high-performance semiconductor devices by incorporating a crack-inhibiting dielectric frame and stress-relief resin layer to manage stress and prevent cracking.
Implementation Method 1
a stress-relief resin layer laterally covers sidewalls of the electrically conductive posts and laterally surrounds a cavity defined above a heat conduction surface of the first conductive island
Implementation Method 2
The first conductive island is spaced from the electrically conductive posts and has a heat conduction surface located at a level between top and bottom sides of the electrically conductive posts
Implementation Method 3
a crack-inhibiting dielectric layer covers the top sides of the electrically conductive posts and top surfaces of the first stress-relief resin layer and the electronic component
Data Source
AI summary
An interconnect board includes a thermally enhanced cavity substrate, an electronic component, a crack-inhibiting dielectric layer and a circuitry layer. The cavity in the thermally enhanced cavity substrate is defined by a heat conduction surface of a first conductive island and inner surrounding sidewalls of a stress-relief resin layer. The thermally enhanced cavity substrate further includes electrically conductive posts as vertical electrical conduction channel. The electronic component in the cavity is attached onto the heat conduction surface and covered and laterally surrounded by the crack-inhibiting dielectric layer. The circuitry layer can provide electrical connections between the electronic component and the electrically conductive posts. For applications involving electrical components with high thermal demand (such as power chips), the first conductive island may further include a metallized segment in contact with the bottom surface of the electronic component to improve thermal management.