Z-Axis Interconnection Structures for Multilayer Electronic Substrates
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Solution Overview
Problem
Current z-axis interconnection methods in multilayer electronic substrates face challenges such as space inefficiency, high yield loss, and compromised fine circuit feature formation due to copper plating, and conventional conductive pastes lack reliability and are not well-suited for high-density interconnect applications.
Innovation Solution
A bonding film with a c-stage thermosetting resin matrix and a b-stage thermosetting resin, optionally with particulate fillers, is used, featuring holes filled with conductive paste, such as TLPS paste, to create reliable and efficient z-axis interconnections that maintain pattern registration and flow control during lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper plating is used for z-axis interconnection, then electrical conductivity is improved, but manufacturing complexity and capital equipment requirements increase
Solution Approach 1:
The patent changes the material parameter from copper plating to conductive paste, and changes the process parameters from electroplating to screen printing and lamination. This eliminates the need for complex plating equipment while achieving reliable electrical conductivity through the conductive paste formulation and processing conditions
Solution Approach 2:
The patent replaces the electrochemical plating system with a mechanical screen printing and lamination system. The conductive paste is applied via screen printing and bonded through thermal compression, eliminating the need for electroplating equipment and reducing manufacturing complexity
2Ease of manufacture
If conventional conductive paste is used, then manufacturing simplicity is improved, but reliability and electrical performance deteriorate
Solution Approach 1:
The patent uses a composite conductive paste formulation containing metal particles, polymer binder, and plasticizer. This composite structure provides both the simplicity of paste application and the reliability of enhanced electrical conductivity, mechanical adhesion, and processability
Solution Approach 2:
The patent modifies the conductive paste parameters including metal particle size distribution, binder composition, and plasticizer content to optimize both electrical performance and manufacturing simplicity. The formulation enables screen printing application while achieving reliable electrical connections
3Ease of operation
If b-stage dielectric is used for lamination, then ease of operation is improved, but resin flow control deteriorates
Solution Approach 1:
The patent modifies the b-stage dielectric parameters including resin composition, crosslink density, and glass fiber content to control resin flow characteristics. These parameter changes enable adequate flow for lamination while preventing excessive flow that would compromise via alignment and interconnection integrity
4Manufacturing precision
If sequential lamination is used, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent performs preliminary actions by pre-forming conductive paste-filled vias in the bonding film before lamination, and by preparing alignment features and registration marks in advance. This preliminary preparation enables accurate pattern registration in sequential lamination while reducing the number of steps required, thereby improving productivity
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 solution enables reliable z-axis interconnections with improved yield and reduced capital equipment needs, maintaining fine circuit feature integrity and electrical performance, while minimizing resin flow issues and thermal expansion mismatches.
Implementation Method 1
a bonding film, which includes a reinforcing matrix of c-stage thermosetting resin surrounded by a b-stage thermosetting resin
Implementation Method 2
Conductive Pastes... Transient liquid phase sintering (TLPS) pastes overcome the fundamental deficiency of conventional conductive pastes by providing a composition that sinters at lamination temperature to create a metallurgically interconnected metallic network
Data Source
AI summary
Invention z-axis interconnection structures provide a means to mechanically and electrically interconnect layers of metallization in electronic substrates reliably and in any configuration. Invention z-axis interconnection structures comprise a novel bonding film and conductive paste and one- and two-piece building block structures formed therefrom.