Capacitor Between Passivation Layers to Reduce Etching Loading
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the formation of integrated circuits, the etching process of passivation layers with different dielectric constants often results in a loading effect, which hinders efficient processing and can lead to defects.
Innovation Solution
A capacitor is formed between two passivation layers with different etching rates, where the first passivation layer has a lower-k value and is etched faster than the second passivation layer, reducing the loading effect during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passivation layers with different dielectric constants are etched using the same etching gas, then the etching process becomes complex and time-consuming, but the loading effect cannot be reduced
Solution Approach 1:
The patent changes the etching parameters by using different etching gases for passivation layers with different dielectric constants. The first passivation layer (lower-k) is etched using a first etching gas, while the second passivation layer (higher-k) is etched using a second etching gas. This parameter change optimizes the etching rate and reduces the loading effect, thereby improving overall etching process efficiency without excessive time loss
Solution Approach 2:
The etching process is segmented into multiple stages, with each passivation layer being etched using a specifically optimized etching gas. This segmentation allows each etching step to be independently optimized for its specific material properties, reducing the overall process complexity and time
2Productivity
If passivation layers with different dielectric constants are etched, then the loading effect increases and processing efficiency decreases, but using different etching gases increases process complexity
Solution Approach 1:
The patent introduces parameter changes by selecting different etching gases based on the dielectric constant of each passivation layer. This systematic parameter change approach, while adding some process complexity, significantly improves processing efficiency by reducing the loading effect and enabling faster, more selective etching of each layer
Solution Approach 2:
The patent uses different etching gases as intermediaries to facilitate the etching of passivation layers with different dielectric constants. Each etching gas acts as a mediator optimized for specific material properties, enabling efficient processing while managing process complexity through systematic material selection
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 configuration allows for a more efficient etching process by minimizing the loading effect, thereby improving the formation of contacts to the capacitor and underlying metal pads.
Implementation Method 1
When etched using a same etching gas, the first passivation layer is etched faster than the second passivation layer, so that in the etching processes, loading effect is reduced
Data Source
AI summary
A method includes depositing a first passivation layer over a conductive feature, wherein the first passivation layer has a first dielectric constant, forming a capacitor over the first passivation layer, and depositing a second passivation layer over the capacitor, wherein the second passivation layer has a second dielectric constant greater than the first dielectric constant. The method further includes forming a redistribution line over and electrically connecting to the capacitor, depositing a third passivation layer over the redistribution line, and forming an Under-Bump-Metallurgy (UBM) penetrating through the third passivation layer to electrically connect to the redistribution line.