Flexible Electronic Parts Packaging Structure with Polyimide Insulating Layers
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Solution Overview
Problem
Existing electronic parts packaging structures face challenges in achieving high reliability and flexibility due to thermal stress-induced warping, particularly when semiconductor chips are mounted on substrates with differing thermal expansion coefficients, and prior methods do not adequately address this issue.
Innovation Solution
A flexible electronic parts packaging structure is developed where semiconductor chips are buried in insulating layers made of polyimide resin, which have a thermal expansion coefficient close to that of the chips, and are covered with additional insulating layers, allowing for thermal stress cancellation and flexibility in mounting, including on curved substrates without the need for adhesive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor chips are mounted on substrates with differing thermal expansion coefficients, then electrical connection is achieved, but thermal stress-induced warping occurs reducing reliability
Solution Approach 1:
The patent applies homogeneity by using insulating layers made of the same material (polyimide resin) on both the upper and lower surfaces of the semiconductor chip. This ensures uniform thermal expansion characteristics throughout the packaging structure, eliminating differential thermal stress that causes warping. The insulating layers are formed by the same manufacturing process and have identical material properties, creating a homogeneous structure that maintains stability during thermal cycling.
Solution Approach 2:
The patent directly addresses thermal expansion by selecting polyimide resin as the insulating layer material because its thermal expansion coefficient closely matches that of the semiconductor chip. This material selection strategy ensures that both the chip and insulating layers expand and contract at similar rates during temperature changes, preventing the generation of thermal stress and subsequent warping that would compromise packaging reliability.
2Adaptability or versatility
If rigid substrates are used for mounting electronic parts, then structural support is provided, but flexibility and ease of mounting are reduced
Solution Approach 1:
The patent replaces traditional rigid substrates with flexible thin film insulating layers made of polyimide resin. These thin films provide sufficient mechanical support for mounting semiconductor chips while enabling the packaging structure to be bent or conform to curved surfaces. The flexible insulating layers maintain structural integrity during handling and mounting processes while allowing adaptability to various mounting configurations including curved substrates.
3Ease of manufacture
If adhesive layers are used to mount semiconductor chips, then secure attachment is achieved, but manufacturing complexity and potential reliability issues are introduced
Solution Approach 1:
The patent eliminates the adhesive layer from the packaging structure by directly bonding the semiconductor chip to the flexible insulating layer through the insulating layer itself. The insulating layer serves dual functions as both the mounting substrate and the bonding interface, removing the need for separate adhesive materials. This extraction of the adhesive layer simplifies the manufacturing process and eliminates potential reliability issues associated with adhesive degradation or delamination.
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
This approach effectively suppresses warping and allows for reliable, compact, and flexible packaging of electronic components, enabling their use in various devices without the need for a dedicated mounting substrate, thus enhancing manufacturing efficiency and device miniaturization.
Implementation Method 1
A thermal stress resulting from a difference in the thermal expansion coefficient between the semiconductor chip (silicon chip) and the core substrate or the insulating layer is ready to occur. Accordingly, there is the problem that a warp is likely to occur in the electronic parts packaging structure.
Implementation Method 2
the flexible electronic parts packaging structure that is easy to be mounted is requested
Data Source
AI summary
An electronic parts packaging structure including an insulating layer acting as a flexible substrate, an electronic parts buried in the insulating layer in a state that a whole electronic parts is covered with the insulating layer, and a wiring layer buried in the insulating layer and connected electrically to a connection pad of the electronic parts. A structure body in which a plurality of electronic parts are buried in the insulating layer may be folded and electronic parts may be connected electrically.