Wiring Substrate With Variable Depth Electrode Pads
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Solution Overview
Problem
Current wiring substrates for semiconductor packages face challenges in miniaturization and thickness reduction, leading to limited flexibility in mounting components due to uniform electrode pad depths, which affects connection reliability.
Innovation Solution
A wiring substrate with first and second electrode pads having different exposed surfaces, achieved through a manufacturing method involving electrolytic plating and depth adjusting films, allowing for varying pad depths and materials to accommodate different components, enhancing mounting flexibility and connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrode pads are formed with uniform depth by conventional methods, then manufacturing process is simple, but mounting flexibility and connection reliability are limited
Solution Approach 1:
The electrode pads are divided into multiple groups (first electrode pads, second electrode pads, third electrode pads) with different depths. Each group serves different mounting functions: first electrode pads for semiconductor chips, second electrode pads for heat sinks, and third electrode pads for additional wiring substrates. This segmentation enables versatile component mounting while maintaining a systematic manufacturing approach through selective etching of depth adjusting films.
Solution Approach 2:
Different regions of the substrate are given different local properties through the depth adjusting films. The first, second, and third electrode pad regions have different film thicknesses, creating local depth variations. This allows each region to be optimized for specific component types, improving mounting flexibility without requiring complete redesign of the entire substrate structure.
2Reliability
If all electrode pads are at the same depth, then manufacturing process is straightforward, but connection strength varies for different components
Solution Approach 1:
Depth adjusting films are formed on all electrode pad regions before the final etching process. These films are removed selectively in subsequent steps to create the desired depth differences. This preliminary action ensures that all electrode pads start at the same depth, providing a uniform baseline for manufacturing, while allowing precise control over final depths through controlled removal of the adjusting films.
Solution Approach 2:
The thickness of depth adjusting films is varied across different electrode pad regions to control final pad depths. By changing the film thickness parameter (first depth adjusting film, second depth adjusting film, third depth adjusting film with different thicknesses), the patent achieves different electrode pad depths, optimizing connection reliability for various components while maintaining a systematic manufacturing process.
3Adaptability or versatility
If electrode pads are recessed to different depths, then mounting flexibility improves, but manufacturing precision requirements increase
Solution Approach 1:
Depth adjusting films serve as intermediary layers between the substrate and the final electrode pad structure. These films act as temporary depth markers that guide the etching process. By controlling the thickness of these intermediary films, the patent achieves precise depth control for different electrode pad groups, enabling versatile mounting options while maintaining manageable manufacturing precision requirements.
Solution Approach 2:
The depth adjusting films are formed in advance with predetermined thicknesses corresponding to the desired final electrode pad depths. This preliminary formation of depth references simplifies the subsequent etching process, as the etching can be controlled to expose electrode pads to the depth of the underlying films, ensuring consistent and precise depth control across different pad groups.
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 improves the reliability and flexibility of component mounting by allowing for depth control and material selection of electrode pads, increasing the degree of freedom in mounting various components and enhancing connection strength and electrical characteristics.
Implementation Method 1
forming first plated films on the depth adjusting films by an electrolytic plating method using the support plate as a plating conduction plate
Data Source
AI summary
There is provided a wiring substrate. The wiring substrate includes: an insulating layer; first electrode pads having first exposed surfaces, the first exposed surfaces being exposed from the insulating layer; and second electrode pads having second exposed surfaces, the second exposed surfaces being exposed from the insulating layer. There is a level difference between the first exposed surfaces and the second exposed surfaces.