Glass-Substrate PCB Through-Vias with Insulating Stress Gaps
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Solution Overview
Problem
Copper Clad Laminates (CCLs) used in package substrates are prone to warpage due to low modulus and high thermal expansion, limiting microcircuit implementation, and through-vias in core substrates with inorganic materials can lead to defects and cracks during processing.
Innovation Solution
A printed circuit board design with gap portions between the through-via and the core layer, filled with insulating material, to mitigate thermal shock and prevent cracks, using a structure with one or more gap portions on the side surfaces of the through-via and filling them with insulating material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through-via is formed in a core substrate with inorganic material, then electrical connection is achieved, but defects and cracks occur during processing due to thermal shock
Solution Approach 1:
An intermediary layer (first insulating layer) is introduced between the through-via and the inorganic core substrate. This intermediary layer acts as a buffer that mitigates thermal shock and prevents direct stress transmission to the core substrate, thereby preventing crack formation while maintaining electrical connection functionality.
Solution Approach 2:
The first insulating layer is formed beforehand to cushion and absorb thermal shock before it reaches the inorganic core substrate. This preemptive cushioning prevents the harmful thermal stress from causing defects and cracks during subsequent processing steps.
2Ease of manufacture
If Copper Clad Laminates are used as core substrate, then ease of manufacture is improved, but warpage occurs due to low modulus and high thermal expansion
Solution Approach 1:
A composite structure is created by combining the inorganic core substrate with an intermediary insulating layer. This composite structure leverages the manufacturing ease of inorganic materials while the intermediary layer compensates for warpage issues by providing a buffer against thermal expansion and mechanical stress.
Solution Approach 2:
The intermediary layer is strategically positioned at specific locations (between the through-via and the core substrate) to provide localized stress relief and warpage compensation. This local quality approach allows the core substrate to maintain its manufacturing advantages while preventing warpage in critical areas.
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 effectively prevents cracks from occurring due to thermal shock, improving stress resistance and reliability of through-vias in core layers with inorganic materials like glass substrates.
Implementation Method 1
forming one or more gap portions, a space separated between a through-via and a core layer, on a side surface of an upper portion and/or a side surface of a lower portion of the through-via, and filling the gap portions with insulating material
Implementation Method 2
offer advantages for thermal shock from a stress perspective
Data Source
AI summary
The present disclosure relates to a printed circuit board including: a frame having a through-portion; a glass substrate in which at least a portion is disposed within the through-portion; a first insulating layer including a first insulating portion covering at least a portion of each of an upper surface of the frame and the glass substrate, a second insulating portion covering at least a portion of each of a lower surface of the frame and the glass substrate, and a third insulating portion filling at least a portion between the frame and the glass substrate; a through-via penetrating the glass substrate between its upper and lower surfaces; a first connection via penetrating at least a portion of the first insulating portion and directly connected to an upper surface of the through-via; and a second connection via penetrating at least a portion of the second insulating portion and directly connected to a lower surface of the through-via.