Metal Electrode Side Wall Inclination for Protective Film Coverage
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Solution Overview
Problem
Existing semiconductor device fabrication methods face challenges in achieving fine processing of metal electrodes with thick metal layers, as wet etching results in isotropic etching, while dry etching can lead to poor coverage of protective films due to perpendicular side walls.
Innovation Solution
A semiconductor device with a metal electrode featuring a side wall structure that includes a lower portion with a steep inclination and an upper portion with a smaller inclination, forming a singular point, allowing for precise control of electrode thickness and improved protective film coverage, achieved through a fabrication method involving dry etching and resist film shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wet etching is used to process the electrode, then a thick metal can be processed at a high etching rate, but fine processing becomes difficult due to isotropic etching
Solution Approach 1:
The etching process is segmented into two distinct stages: a first etching process that creates an initial opening and a second etching process that performs fine processing. This segmentation allows each process to be optimized independently - the first process can use wet etching for high speed, while the second process uses dry etching for precision, thereby resolving the contradiction between etching rate and fine processing capability.
2Manufacturing precision
If dry etching is used to process the electrode in the perpendicular direction, then fine processing can be performed easily, but the coverage of protective film formed above the electrode is deteriorated due to perpendicular side wall
Solution Approach 1:
The side wall of the electrode opening is designed with different inclinations at different heights. The lower portion has a first inclination angle while the upper portion has a second inclination angle that is smaller than the first. This local variation in geometry allows the upper portion to provide better coverage for protective films while the lower portion maintains the fine processing capability achieved through dry etching.
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
Enables the formation of thick field plates at fine intervals with improved protective film coverage, enhancing the miniaturization and reliability of semiconductor devices.
Implementation Method 1
processing the electrode in the perpendicular direction by dry etching or the like allows a fine processing to be performed easily
Data Source
AI summary
The position of the side wall of a metal electrode is precisely controlled and the coverage of a layer above the metal electrode is improved. A semiconductor device is provided, including: a semiconductor substrate; and a metal electrode formed above an upper surface of the semiconductor substrate, wherein a side wall of the metal electrode includes a lower portion contacting the semiconductor substrate, and an upper portion that is formed upper than the lower portion and has a smaller inclination relative to the upper surface of the semiconductor substrate than the lower portion. An active region formed in the semiconductor substrate is further included, and the metal electrode may be a field plate formed on an outer side relative to the active region on the upper surface of the semiconductor substrate. The upper portion of the side wall of the field plate may have an upward-convex shape.