Conductive Pad Etch Stop Layer for Thin Film Via Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fabricating contacts or vias to thin film conductive materials in semiconductor devices is challenging due to damage during via etching and chemical cleaning processes, leading to poor electrical contact.
Innovation Solution
Incorporating conductive pads as etch stop layers to provide reliable electrical contact and increase processing margin for via etching, with the conductive pads being part of the structure that vias penetrate through, ensuring they touch the surface of the pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via etching and chemical cleaning processes are performed on thin film conductive material, then electrical contact is achieved, but the thin film conductive material is damaged
Solution Approach 1:
A conductive pad layer is introduced as an intermediary between the via and the thin film conductive material. The pad layer serves as a mediator that receives the via connection while protecting the underlying thin film conductive material from damage during etching and chemical cleaning processes.
Solution Approach 2:
The conductive pad layer is formed in advance before the via etching and chemical cleaning processes. This preliminary structure provides a robust target for via formation and protects the thin film conductive material before any damaging processes occur.
2Reliability
If chemical cleaning processes are performed after etching, then via cleanliness is improved, but the thin film conductive material is attacked and damaged
Solution Approach 1:
The conductive pad layer acts as a protective intermediary that shields the thin film conductive material from chemical cleaning processes. Chemical cleaners can aggressively clean the via and pad surfaces without damaging the underlying thin film conductive material.
Solution Approach 2:
The conductive pad layer provides beforehand protection or cushioning to the thin film conductive material against chemical attack. The pad layer is designed to be chemically resistant, absorbing the harsh cleaning conditions before they can reach the thin film conductive material.
3Productivity
If the thin film of metal is made thinner to reduce device size, then device scaling is improved, but the thin film becomes more susceptible to damage during via etching
Solution Approach 1:
The conductive structure is segmented into multiple layers: the thin film conductive material layer and the thicker conductive pad layer. This segmentation allows the thin film to maintain its thin profile for device scaling while the separate pad layer provides mechanical strength and damage resistance.
Solution Approach 2:
The solution moves the protective function to another dimension by adding a vertical layer (the conductive pad) rather than thickening the horizontal thin film. This allows the thin film to remain thin for scaling while the pad layer provides the necessary structural protection in the vertical dimension.
Data Source
AI summary
A structure comprises a substrate and a conductive pad disposed over the substrate. A conductive layer overlies the conductive pad. A via is disposed over the conductive pad. The via penetrates through the conductive layer and touches a surface of the conductive pad.