Metal Silicide Plug Etching Protection for Semiconductor Reliability
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Solution Overview
Problem
The reliability and manufacturing cost of semiconductor devices using SOI substrates are not adequately addressed in existing technologies, with issues related to epitaxial layer formation and metal silicide layer thickness affecting device performance and cost.
Innovation Solution
A method involving epitaxial growth of a semiconductor layer on both sides of the gate electrode, followed by silicidation to form a metal silicide layer, and precise etching to form a plug structure, ensuring the metal silicide layer is not excessively etched, thereby maintaining device reliability and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used to form openings through insulating layers, then the openings can be formed, but the metal silicide layer is excessively etched, reducing device reliability
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the metal silicide layer before the etching process. This protective film is formed in advance to prevent excessive etching of the metal silicide layer during subsequent opening formation, thereby resolving the contradiction between forming precise openings and maintaining device reliability.
Solution Approach 2:
The patent uses an intermediary substance (protective film) that mediates between the etching process and the metal silicide layer. This protective film acts as a barrier that allows opening formation while preventing excessive etching of the metal silicide layer, thus maintaining both manufacturing precision and device reliability.
2Ease of manufacture
If the metal silicide layer thickness is reduced to lower manufacturing cost, then cost decreases, but electrical connection quality deteriorates
Solution Approach 1:
The patent employs a disposable protective film that is formed temporarily to protect the metal silicide layer during etching. This protective film can be a simpler, lower-cost material that serves its protective function and is then removed, allowing the use of thinner metal silicide layers without compromising electrical connection quality, thus reducing manufacturing cost while maintaining reliability.
3Reliability
If epitaxial growth is performed to form semiconductor layers on both sides of the gate electrode, then source/drain regions are formed, but the process complexity increases
Solution Approach 1:
The patent merges the formation of source/drain regions with the epitaxial growth process by performing epitaxial growth on both sides of the gate electrode simultaneously. This combining of operations forms both source and drain regions in a single integrated process step, improving device performance while managing process complexity through consolidation rather than separate sequential steps.
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 method enhances the reliability of semiconductor devices by preventing excessive etching of the metal silicide layer and maintaining its thickness, improving the electrical connection and reducing manufacturing costs by optimizing the epitaxial growth and etching processes.
Implementation Method 1
forming an epitaxial layer on the semiconductor layer located at both sides of the gate electrode by an epitaxial growth method
Implementation Method 2
forming a metal silicide layer in the epitaxial layer by silicidation of the epitaxial layer
Data Source
AI summary
After a MISFET is formed on a substrate including a semiconductor substrate, an insulating layer and a semiconductor layer, an interlayer insulating film and a first insulating film are formed on the substrate. Also, after an opening is formed in each of the first insulating film and the interlayer insulating film, a second insulating film is formed at each of a bottom portion of the opening and a side surface of the opening and also formed on an upper surface of the first insulating film. Further, each of the second insulating film formed at the bottom portion of the opening and the second insulating film formed on the upper surface of the first insulating film is removed by etching. After that, an inside of the opening is etched under a condition that each of the first insulating film and the second insulating film is less etched than the insulating layer.