Plated Electrode Undercut Reduction for Semiconductor Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor device manufacturing processes face challenges with the overhung metal edges of plated electrodes, leading to inadequate contact between the insulating film and the plated metal, which degrades the long-term reliability of the semiconductor device.
Innovation Solution
The process involves forming a second electrode that extends around the opening in the insulating film, followed by a mask that exposes the edge of the second electrode, allowing for the formation of a third electrode with a reduced undercut aspect ratio, enabling better coverage by a second insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If plated metal is formed to fully cover the opening and extend on the insulating film, then the coverage of the electrode is improved, but the insulating film cannot contact the deep end of the overhung plated metal, degrading long-term reliability
Solution Approach 1:
The electrode structure is divided into multiple segments: a first plated metal layer that fills the opening, a second plated metal layer that forms the interconnection, and an optional third plated metal layer for additional coverage. This segmentation allows each layer to serve specific functions - the first layer provides base coverage, the second layer creates the extended interconnection, and the third layer (when used) ensures insulating film contact, thereby resolving the contradiction between coverage area and reliability.
2Shape
If the plated metal has an overhung side surface with undercut, then the electrode coverage is enhanced, but the insulating film or passivation film covering the plated metal is hard to be in contact to a deep end of the overhung plated metal
Solution Approach 1:
The insulating film is formed to extend onto the insulating film surface before the plated metal overhang is created. This preliminary extension of the insulating film ensures that when the plated metal forms its overhung structure with undercut, the insulating film is already positioned to make contact with the deep end of the overhung plated metal, thereby maintaining manufacturing precision while achieving the desired shape.
3Device complexity
If a single plating step is used to form the interconnection, then the process complexity is reduced, but the coverage and reliability of the plated metal are insufficient
Solution Approach 1:
The plating process is segmented into multiple sequential steps: first plating to form the base electrode, second plating to form the interconnection layer, and third plating (when used) to form an additional protective layer. Each plating step uses different plating solutions and parameters optimized for its specific purpose, thereby achieving high reliability without excessive complexity.
Solution Approach 2:
A seed layer is formed on the substrate before the first plating step. This preliminary seed layer provides a foundation that enhances adhesion and ensures uniform plating, thereby improving the reliability of the subsequent plated metal layers without significantly increasing 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
This approach enhances the coverage of the insulating film over the overhung metal edges, improving the long-term reliability of the semiconductor device by reducing the undercut aspect ratio and ensuring effective contact between the electrodes and the passivation film.
Implementation Method 1
forming a second electrode on a portion of the first electrode exposed within the opening and a portion of the first insulating film around the opening of the first insulating film
Data Source
AI summary
A process to form an electrode of a semiconductor device is disclosed. The process includes steps of: forming the first electrode on the semiconductor layer; forming the first insulating film on the first electrode, where the first insulating film provides an opening that exposes a portion of the first electrode but fully covers the semiconductor layer; fully filling the opening by the second electrode; forming the mask so as to expose the second electrode but fully cover the sides of the second electrode; forming the third electrode in a region exposing from the mask; and removing the mask.