Conductive Layer Stack Layout for Low-Warpage Signal Substrates
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Solution Overview
Problem
The warpage of substrates in electronic devices due to differences in thermal expansion coefficients between metal layers and substrates leads to abnormal signal transmission and reduced reliability, particularly as metal layer thickness increases, necessitating costly thinning processes to mitigate warpage.
Innovation Solution
The implementation of a substrate with a first conductive layer, a second conductive layer, and a first inorganic insulating layer, where the insulating layer is thinner than the conductive layers and strategically positioned to reduce warpage and signal penetration, utilizing specific thicknesses and widths to minimize signal loss and warpage without increasing substrate thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the metal layer is increased, then the electrical conductivity is improved, but the substrate warpage increases
Solution Approach 1:
The patent divides the single thick metal layer into multiple thinner metal layers separated by inorganic insulating layers. This segmentation maintains the total metal thickness for electrical conductivity while distributing the thermal expansion stress across multiple interfaces, reducing substrate warpage.
Solution Approach 2:
The inorganic insulating layers act as intermediary elements between the metal layers and the substrate. These intermediate layers have different thermal expansion coefficients than the metal, serving as buffer zones that reduce the thermal stress transmitted to the substrate, thereby minimizing warpage while allowing thick metal structures for good conductivity.
2Shape
If the thickness of the substrate is increased to reduce warpage, then the substrate warpage is reduced, but the process cost increases due to required thinning processes
Solution Approach 1:
The patent applies preliminary action by incorporating the inorganic insulating layers during the metal layer formation process itself, rather than adding them as a separate corrective step after substrate warpage occurs. This prevents warpage during manufacturing, eliminating the need for subsequent substrate thinning processes and reducing overall manufacturing cost.
Solution Approach 2:
The patent converts the potentially harmful effect of thermal expansion differences into a beneficial structure. The inorganic insulating layers, which could be seen as adding complexity, actually serve to absorb thermal stress and prevent warpage, transforming what would be a manufacturing problem into a design feature that simplifies the overall process by eliminating post-manufacturing thinning operations.
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 configuration effectively reduces substrate warpage and signal loss, enhancing the reliability and efficiency of electronic devices by maintaining signal integrity and reducing manufacturing costs associated with thickness adjustments.
Implementation Method 1
A metal layer and a substrate for forming an electronic device include different materials and different physical properties (e.g., thermal expansion coefficients). Therefore, warpage generated in the substrate during a process of manufacturing the electronic device
Data Source
AI summary
An electronic device includes a substrate, a first conductive layer, a second conductive layer, and a first inorganic insulating layer. The first conductive layer is disposed on the substrate. The second conductive layer comprises a first surface and a second surface opposite to the first surface, wherein the second surface is closer to the first conductive layer than the first surface. The first inorganic insulating layer is disposed between the first conductive layer and the second conductive layer. In a cross-sectional view of the electronic device, the second surface of the second conductive layer comprises a first portion, a second portion and a third portion arranging in sequence along a first direction and contacting the first conductive layer, and a thickness of the first inorganic insulating layer is less than a thickness of the second conductive layer.