Multi-Trace Via Fabrication Using Photoresist Masking
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Solution Overview
Problem
Current methods for manufacturing multi-trace via substrates are time-consuming and prone to damaging the dielectric layer, leading to reduced yield rates and stability issues due to the use of laser cutting for forming circuit patterns on conductive materials.
Innovation Solution
A method involving the formation of a substrate with a conductive layer, application of a photoresist layer, selective patterning, and electroplating to create laterally separated traces on the surface and through holes without damaging the insulating material, using the patterned photoresist layer as a mask to ensure the second conductive layer is thicker and covers the first conductive layer, thereby forming complete and intact traces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laser cutting is used to form circuit patterns on conductive materials, then multi-trace via substrates can be manufactured, but the process is time-consuming and may damage the dielectric layer surface
Solution Approach 1:
The patent applies preliminary action by pre-forming a continuous conductive layer that covers the hole wall and surface before patterning. This allows subsequent photoresist application and electroplating to proceed efficiently without requiring time-consuming laser cutting, thereby reducing manufacturing time while maintaining multi-trace via functionality
Solution Approach 2:
The patent replaces the mechanical laser cutting process with a photochemical-electrochemical system. Instead of using laser energy to cut and shape conductive materials, the invention uses photoresist patterning followed by electroplating to form the desired trace structures, which is both faster and less damaging to the dielectric layer
2Adaptability or versatility
If laser cutting is used to form circuit patterns, then multi-trace via substrates can be manufactured, but the dielectric layer surface may be damaged affecting yield rate
Solution Approach 1:
The patent replaces the harmful laser cutting process with a gentler photochemical-electrochemical approach. The photoresist layer selectively protects areas during electroplating, forming traces without direct contact or thermal damage to the dielectric layer, thereby improving yield rate and reliability
Solution Approach 2:
The patent introduces photoresist as an intermediary substance that mediates between the electroplating process and the dielectric layer. The photoresist pattern acts as a protective mask during electroplating, preventing damage to the dielectric layer while enabling precise trace formation, thus improving yield rate
3Quantity of substance
If plated through hole size is reduced to increase density, then more plated through holes can be disposed in the same area, but manufacturing becomes difficult and stability deteriorates
Solution Approach 1:
The patent applies segmentation by dividing a single plated through hole into multiple laterally separated traces through photoresist patterning and selective electroplating. This allows one via to serve multiple circuit functions, increasing the effective number of functional connections without requiring additional small plated through holes, thereby maintaining manufacturing stability
Solution Approach 2:
The patent makes a single plated through hole universal by forming multiple traces within it. The via structure serves multiple circuit connection functions simultaneously, eliminating the need for multiple separate small plated through holes and maintaining manufacturing stability while achieving high density
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 method allows for the quick and accurate fabrication of multi-trace via substrates with intact insulating layers, increasing yield rates and avoiding damage to the dielectric material, thus improving the manufacturing efficiency and product stability.
Implementation Method 1
selectively patterning photoresist layer so as to define a plurality of laterally separated regions on the first conductive layer
Implementation Method 2
electroplating a second conductive layer substantially thicker than the first conductive layer on the laterally separated regions
Data Source
AI summary
A method of fabricating a multi-trace via substrate is disclosed. A substrate at least having a first surface and a hole is provided, wherein the hole has a hole wall. A first conductive layer is formed on the entire surface of the substrate and the hole wall. A photoresist layer applied over the entire surface of the first conductive layer is selectively patterned to define a plurality of laterally separated regions on the first conductive layer. A patterned photoresist layer is used as a mask and a second conductive layer substantially thicker than the first conductive layer is electroplated on the laterally separated regions. The patterned photoresist layer is removed. The portion of the first conductive layer not covered by the second conductive layer is substantially removed to form a plurality of laterally separated traces extended on the first surface and through the hole.