Silicon Bridge Pad Surfaces With Thin Copper to Limit Wafer Bowing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving compact, high-density circuit designs with minimal warpage and efficient assembly processing, particularly due to the use of thick copper pad layers in silicon bridges, which require lengthy processing times and can cause wafer bowing issues.
Innovation Solution
Incorporating a thin copper pad layer with a silicon nitride protecting layer, which reduces the need for extensive copper pad etching and processing, allowing for improved throughput and mitigating wafer bowing, while enhancing adhesion and reliability through the deposition of a silicon nitride layer on the copper pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick copper pad layer is used in silicon bridges, then adhesion and electrical connection are improved, but processing time increases and wafer bowing occurs
Solution Approach 1:
The patent changes the thickness parameter of the copper pad layer from conventional thick (typically 5-10 micrometers) to thin (1-3 micrometers), fundamentally altering the processing requirements and outcomes. This parameter change reduces etching time, eliminates wafer bowing, and maintains adequate electrical performance for the application
Solution Approach 2:
The patent creates a composite pad structure by depositing a silicon nitride protecting layer over the thin copper pad layer. This composite structure provides both the electrical conductivity of copper and the protective/adhesive properties of silicon nitride, achieving reliability without requiring thick copper
2Reliability
If a thick copper pad layer is used in silicon bridges, then adhesion is improved, but wafer bowing is caused
Solution Approach 1:
By changing the copper pad thickness parameter to a thin layer (1-3 micrometers), the patent eliminates the excessive material deposition that causes wafer bowing during processing, while maintaining adequate adhesion through the optimized thin layer and protective coating
Solution Approach 2:
The composite structure of thin copper pad plus silicon nitride protecting layer provides the adhesion functionality without requiring thick copper, thereby maintaining wafer flatness and eliminating bowing issues during fabrication
3Productivity
If a thin copper pad layer is used, then processing time is reduced and wafer bowing is eliminated, but adhesion may be compromised
Solution Approach 1:
The patent applies a silicon nitride protecting layer over the thin copper pad layer, creating a composite structure where the silicon nitride provides the protective and adhesive functions that would otherwise require thick copper, thereby maintaining reliability with thin copper processing
Solution Approach 2:
The silicon nitride protecting layer serves multiple functions simultaneously: it protects the thin copper pad from oxidation and damage during assembly, provides adhesion for subsequent bonding processes, and enables the use of thin copper without compromising reliability
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 approach results in a more efficient fabrication process with reduced processing time and improved wafer thinning yield, eliminating the need for lengthy copper plating processes and minimizing wafer bowing, thus enabling the production of compact, high-performance semiconductor packages.
Implementation Method 1
the deposition of a silicon nitride layer on the copper pad
Data Source
AI summary
Alternative surfaces for conductive pad layers of silicon bridges for semiconductor packages, and the resulting silicon bridges and semiconductor packages, are described. In an example, a semiconductor structure includes a substrate having a lower insulating layer disposed thereon. The substrate has a perimeter. A metallization structure is disposed on the lower insulating layer. The metallization structure includes conductive routing disposed in a dielectric material stack. First and second pluralities of conductive pads are disposed in a plane above the metallization structure. Conductive routing of the metallization structure electrically connects the first plurality of conductive pads with the second plurality of conductive pads. An upper insulating layer is disposed on the first and second pluralities of conductive pads. The upper insulating layer has a perimeter substantially the same as the perimeter of the substrate.