Hybrid Wiring Substrate for High-Current and Fine-Pitch Packaging
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Solution Overview
Problem
Existing wiring technologies face challenges in managing heat generation due to large current applications in power semiconductor devices, particularly in stacked-type packages, where thick wiring is needed to suppress heat but is difficult to fabricate and integrate, and electroplating methods are inefficient for forming thick layers, leading to manufacturing inefficiencies and cost increases.
Innovation Solution
A hybrid wiring structure combining a thick metal layer formed using a metal plate for high current conduction and a thin layer formed through electroplating for microfabrication, where the thin layer is used in regions with low current flow to enable high integration wiring, allowing both power devices and control ICs to be connected in the same layer with different design rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thick wiring layer is used to suppress heat generation from large current, then heat management is improved, but manufacturing complexity and cost increase due to difficulty in fabricating and integrating thick layers
Solution Approach 1:
The wiring structure is segmented into multiple layers: a first wiring layer formed by electroplating and a second wiring layer formed by bonding a metal plate. This segmentation allows each layer to be optimized for its specific function - the first layer for electrical connection and the second layer for high-current conduction with heat dissipation, thereby reducing overall manufacturing complexity while managing heat effectively
Solution Approach 2:
The patent employs a composite wiring structure combining different materials and formation methods - electroplated metal layer and bonded metal plate layer. This composite approach enables the wiring to simultaneously achieve good electrical conductivity, high current-carrying capacity, and effective heat dissipation without requiring a single thick layer that would be difficult to manufacture
2Ease of manufacture
If electroplating method is used to form thick wiring layers, then manufacturing process is simplified, but manufacturing efficiency decreases and cost increases due to inefficiency in forming thick layers
Solution Approach 1:
The patent applies preliminary action by forming the first wiring layer through electroplating before bonding the metal plate. This preliminary electroplating layer provides a foundation for subsequent metal plate bonding, enabling efficient formation of thick wiring structures without relying solely on time-consuming electroplating processes for the entire thickness
Solution Approach 2:
The electroplated first wiring layer serves as an intermediary between the substrate and the bonded metal plate. This intermediary layer facilitates the bonding process and ensures good electrical and mechanical connection, allowing efficient manufacturing of thick wiring structures by combining electroplating advantages with metal plate bonding efficiency
3Temperature
If a thick wiring layer is used for high current conduction, then heat management is improved, but integration with control ICs and power devices becomes difficult
Solution Approach 1:
The patent applies local quality by having different wiring layer configurations in different regions: the first wiring layer formed by electroplating provides fine-pitch connectivity suitable for control ICs, while the second wiring layer formed by bonding metal plates provides thick, low-resistance paths for high-current power devices. This local differentiation enables simultaneous integration of both control and power functions with appropriate heat management
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 enables efficient heat management by using the thick layer for main current conduction and the thin layer for high integration wiring, allowing for simultaneous patterning and connection of power and control ICs, thereby improving manufacturing efficiency and reducing heat generation while maintaining high integration and cost-effectiveness.
Implementation Method 1
The second layer is in direct contact with the first wiring in the via
Implementation Method 2
electroplating methods are inefficient for forming thick layers
Data Source
AI summary
Provided is a wiring substrate and its manufacturing method in which a thick wiring layer capable of being applied with a large current and a thin wiring layer capable of being subjected to microfabrication coexist in the same layer. The wiring substrate includes: an insulating film located over a first wiring and having a via; and a second wiring over the insulating film. The second wiring has a stacked structure including a first layer and a second layer covering the first layer. The second layer is in direct contact with the first wiring in the via. A thickness of the second layer in a region overlapping with the first layer is different from a thickness of the second layer in the via.