Protected Redistribution Lines for Oxidation Resistance and Adhesion
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Solution Overview
Problem
Existing technologies face challenges in effectively protecting redistribution lines from oxidation and improving adhesion between conductive features and dielectric layers in semiconductor packages, which can lead to reliability issues and performance degradation.
Innovation Solution
The formation of protection layers on redistribution lines using conductive materials like Ni, Sn, Ag, Cr, Ti, or Pt, or their alloys, which are plated onto the redistribution lines to provide oxidation resistance and enhance adhesion to dielectric layers, while also forming Under-Bump-Metallurgy (UBM) for electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redistribution lines are formed without protection layers, then the manufacturing process is simpler, but the conductive materials are susceptible to oxidation and adhesion is poor
Solution Approach 1:
A protection layer comprising Ni, Sn, Ag, Cr, Ti, Pt or their alloys is deposited as an intermediary between the conductive material and the environment/dielectric layer. This protection layer serves as a mediator that prevents direct contact between oxygen/moisture and the conductive material, thereby preventing oxidation and improving adhesion without requiring fundamental changes to the redistribution line structure
Solution Approach 2:
The redistribution line structure is transformed into a composite material system consisting of multiple layers: the base conductive material layer and the protection layer comprising reactive metals (Ni, Sn, Ag, Cr, Ti, Pt or their alloys). This composite structure combines the electrical conductivity of the base material with the oxidation resistance and adhesion properties of the protection layer
2Reliability
If protection layers are plated onto redistribution lines, then oxidation resistance and adhesion are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The mechanical deposition process is replaced with electrochemical plating to form the protection layer. Instead of physically depositing material through vacuum or other mechanical means, the patent uses electrochemical reactions to deposit Ni, Sn, Ag, Cr, Ti, Pt or their alloys onto the conductive material, enabling better control over layer thickness and composition while maintaining manufacturing efficiency
Solution Approach 2:
The manufacturing process parameters are optimized by controlling the plating conditions (electrolyte composition, current density, temperature, time) to achieve the desired protection layer thickness and composition. By adjusting these parameters, the process can be tuned to balance protection performance with manufacturing complexity, ensuring reliable oxidation resistance and adhesion without excessive process complexity
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 effectively reduces oxidation of conductive materials and enhances the adhesion between redistribution lines and dielectric layers, improving the reliability and performance of semiconductor packages.
Implementation Method 1
The solution effectively reduces oxidation of conductive materials
Implementation Method 2
enhances the adhesion between redistribution lines and dielectric layers
Data Source
AI summary
A method includes forming a metal seed layer over a first conductive feature of a wafer, forming a patterned photo resist on the metal seed layer, forming a second conductive feature in an opening in the patterned photo resist, and heating the wafer to generate a gap between the second conductive feature and the patterned photo resist. A protection layer is plated on the second conductive feature. The method further includes removing the patterned photo resist, and etching the metal seed layer.