Wiring Substrate Reinforcement Pattern Insulation Reliability
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Solution Overview
Problem
In wiring substrates with NSMD structure, high temperature treatments like reflow soldering cause stress and cracking at the interface between insulating layers due to differing thermal expansion coefficients, reducing insulation reliability.
Innovation Solution
A wiring substrate design featuring a reinforcement wiring pattern surrounding the pad without contact, with the second insulating layer's inner side surface defining an opening that exposes the pad, ensuring no direct interface between insulating layers and thus preventing cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If NSMD structure is used with direct interface between insulating layers, then manufacturing is simpler, but cracking occurs during high temperature treatment due to thermal expansion stress
Solution Approach 1:
The patent introduces a reinforcement wiring pattern as an intermediary layer between the first and second insulating layers. This reinforcement pattern serves as a stress-absorbing intermediary that prevents direct stress transmission across the insulating layer interface during thermal expansion, thereby eliminating cracking while maintaining the NSMD structural simplicity
Solution Approach 2:
The reinforcement wiring pattern is positioned beforehand at the interface region between insulating layers to provide preemptive stress cushioning. This pre-positioned reinforcement absorbs thermal expansion stresses before they can cause cracking, ensuring insulation reliability without complicating the manufacturing process
2Reliability
If reinforcement wiring pattern is added to prevent cracking, then insulation reliability improves, but device complexity increases
Solution Approach 1:
The reinforcement wiring pattern serves multiple functions simultaneously: it reinforces the insulating layer interface to prevent cracking, provides electrical connection pathways, and acts as a stress distribution network. This multi-functionality allows the structure to improve reliability without proportionally increasing complexity
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 design enhances insulation reliability by preventing cracks and chipping during high temperature treatments, maintaining connection reliability between the substrate and semiconductor chips or other substrates.
Implementation Method 1
high temperature treatments like reflow soldering cause stress and cracking at the interface between insulating layers due to differing thermal expansion coefficients
Implementation Method 2
The second insulating layer includes an opening in which the pad is exposed without contacting the second insulating layer. The inner side surface is on the reinforcement wiring pattern.
Data Source
AI summary
A wiring substrate includes a first insulating layer, a pad on a surface of the first insulating layer, a reinforcement wiring pattern in or on the surface of the first insulating layer, and a second insulating layer on the surface of the first insulating layer. The reinforcement wiring pattern surrounds the pad without contacting the pad in a plan view. The second insulating layer includes an opening in which the pad is exposed without contacting the second insulating layer. The second insulating layer includes an inner side surface defining the opening. The inner side surface is on the reinforcement wiring pattern.