Embedded Aluminum Pads in Package Substrates for Wire Bonding
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Solution Overview
Problem
Current package substrates face challenges in reducing thickness and increasing density, particularly in incorporating embedded pads without protrusion, which affects fabrication costs and reliability in wire bonding processes.
Innovation Solution
The integration of embedded aluminum pads within the insulating layer of package substrates, where the pads are not protruding outside, allows for improved spacing and reduced fabrication costs by using aluminum as a conductive material, enhancing electrical conductivity and reliability in wire bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal plating techniques are used to treat PCB surfaces, then electrical conductivity and reliability are improved, but fabrication cost and process complexity increase
Solution Approach 1:
The patent replaces expensive traditional metal plating processes with a cost-effective aluminum pad embedding technique. Aluminum is used as a cheaper alternative to traditional plated metals, and the embedding method simplifies the fabrication process while maintaining wire bonding reliability
Solution Approach 2:
The patent changes the material parameter from traditional plated metals to aluminum, and changes the structural parameter from surface plating to embedded pads within the insulating layer. This parameter change reduces fabrication cost while maintaining the necessary electrical conductivity for wire bonding
2Length of stationary object
If PCB thickness is reduced to increase component density, then device miniaturization is achieved, but structural integrity and manufacturing difficulty worsen
Solution Approach 1:
The patent moves the conductive pads from the traditional surface plane into the thickness dimension by embedding them within the insulating layer. This dimensional change allows for thinner overall substrate thickness while maintaining adequate pad spacing and structural integrity, thereby enabling device miniaturization without excessive manufacturing difficulty
3Reliability
If pad spacing is increased to improve wire bonding reliability, then bonding accuracy is improved, but substrate area increases
Solution Approach 1:
By embedding pads within the insulating layer rather than placing them on the surface, the patent creates vertical separation between pads. This allows for reduced horizontal pad spacing while maintaining adequate bonding access and reliability, thereby reducing substrate area without compromising wire bonding performance
4Length of stationary object
If aluminum pads are embedded in insulating layer without protrusion, then substrate thickness is reduced, but pad accessibility for bonding deteriorates
Solution Approach 1:
The patent creates a composite structure where aluminum pads are embedded within the insulating layer, forming an integrated material system. The insulating layer is configured to expose sufficient pad surface area while maintaining overall substrate thinness, achieving both reduced thickness and adequate accessibility through material integration
Data Source
AI summary
A package substrate including an insulating layer having a top surface and a bottom surface opposite to the top surface, at least one first copper pattern disposed in the insulating layer and adjacent to the top surface of the insulating layer, at least one second copper pattern disposed on the bottom surface of the insulating layer, and at least one embedded aluminum pad disposed on the at least one first copper pattern, the at least one embedded aluminum pad disposed in the insulating layer such that a top surface of the at least one embedded aluminum pad is exposed by the insulating layer may be provided.