PCB Insulating Member Reduces Warpage via Elasticity
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Solution Overview
Problem
Current printed circuit boards face challenges in increasing functionality and reliability due to limited data on the embedding of components, leading to issues with warpage and stress during manufacturing processes, especially with the use of passivation materials that have different mechanical properties compared to the board materials.
Innovation Solution
A printed circuit board design incorporating a core board with an insulating layer and a cavity, featuring an insulating member with a lower modulus of elasticity than the insulating layer, which is placed between the electronic element and the cavity walls to alleviate stress and control warpage, along with additional insulating layers with varying properties to manage thermal expansion and mechanical flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electronic components are embedded into printed circuit boards to increase functionality, then the board can perform electrical roles with active and passive devices, but warpage and stress issues occur during manufacturing due to different mechanical properties between passivation materials and board materials
Solution Approach 1:
The patent introduces an insulating member as an intermediary substance between the electronic component and the cavity wall. This insulating member has a modulus of elasticity lower than the insulating layer, allowing it to act as a stress-absorbing buffer that accommodates the mechanical property differences between the passivation material and board materials, thereby preventing warpage while enabling component embedding for enhanced functionality
Solution Approach 2:
The patent changes the mechanical parameter (modulus of elasticity) of the insulating member to be lower than that of the insulating layer. This parameter modification allows the insulating member to deform more easily under stress, absorbing thermal expansion differences and mechanical stresses during manufacturing processes, thus maintaining manufacturing reliability while enabling embedded components for increased adaptability
2Strength
If passivation materials with different mechanical properties are used to protect electronic elements, then the elements are protected, but stress and warpage are generated during manufacturing processes
Solution Approach 1:
The patent applies local quality by making the insulating member's mechanical properties (modulus of elasticity) different from and lower than the insulating layer. This localized property differentiation allows the insulating member to specifically address stress concentration at the component-cavity interface while maintaining the overall protective function, thus preventing warpage without compromising protection
Solution Approach 2:
The insulating member serves as a pre-positioned cushioning layer between the passivation material and the cavity wall. By having lower modulus of elasticity, it anticipates and absorbs thermal expansion stresses and mechanical loads before they can propagate to cause warpage, thereby protecting the electronic element while maintaining board flatness during manufacturing
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 solution effectively reduces contraction stress and warpage on the printed circuit board by using a low-modulus insulating member and strategically placed insulating layers with specific thermal expansion properties, enhancing the board's mechanical stability and reliability during manufacturing and usage.
Implementation Method 1
an insulating member disposed between inner surfaces of the cavity and the electronic element, wherein a modulus of elasticity of the insulating member is lower than a modulus of elasticity of the insulating layer
Implementation Method 2
At least one of the insulating member and the first insulating layer may include a modulus of elasticity and a coefficient of thermal expansion lower than a modulus of elasticity and a coefficient of thermal expansion of the second insulating layer
Data Source
AI summary
There are provided a printed circuit board and a method to manufacture the same. The printed circuit board includes a core board including an insulating layer and a cavity, an electronic element in the cavity, and an insulating member disposed between inner surfaces of the cavity and the electronic element. A modulus of elasticity of the insulating member is lower than a modulus of elasticity of the insulating layer.