Semiconductor Device Cover Layer for Metal Residue Removal
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Solution Overview
Problem
Metal residues left after silicidation in semiconductor fabrication severely affect the electrical characteristics of semiconductor devices, particularly causing time-dependent dielectric breakdown and reducing breakdown voltage.
Innovation Solution
A cover layer is selectively formed over the metal-semiconductor compound film to enclose unreacted metal residues, making them easier to remove through a wet cleaning process, thereby alleviating electrical issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicidation is used to form low resistivity contacts, then electrical conductivity is improved, but metal residues remain that cause time-dependent dielectric breakdown and reduce breakdown voltage
Solution Approach 1:
The patent extracts and removes the harmful metal residues from the semiconductor structure through a selective removal process. The cover layer is formed to enclose the metal-semiconductor compound, and then metal residues exposed at the surface are selectively removed while preserving the enclosed compound, thereby eliminating the harmful effects of metal residues on electrical characteristics
Solution Approach 2:
The patent introduces a cover layer as an intermediary structure that encloses the metal-semiconductor compound. This cover layer acts as a protective barrier that allows the beneficial low-resistivity contact to be formed while preventing metal residues from causing dielectric breakdown. The intermediary structure mediates between the need for conductive contact and the need to eliminate harmful metal residues
2Ease of manufacture
If a cover layer is formed to enclose metal residues, then metal residue removal is facilitated, but device structure complexity increases
Solution Approach 1:
The cover layer is formed in advance before the metal residue removal process. By preliminarily enclosing the metal-semiconductor compound with the cover layer, the subsequent removal of metal residues becomes easier and more selective. The preliminary formation of the cover layer structure enables controlled access to and removal of only the exposed metal residues without affecting the enclosed compound
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
The solution effectively reduces time-dependent dielectric breakdown and improves breakdown voltage by facilitating the removal of metal residues, enhancing the electrical characteristics of semiconductor devices.
Implementation Method 1
the metal layer is thermally treated to render the metal layer react with the semiconductor structure to form a metal-semiconductor compound film
Implementation Method 2
the metal layer is thermally treated to render the metal layer react with the semiconductor structure to form a metal-semiconductor compound film
Implementation Method 3
a wet cleaning operation is performed to remove the unreacted metal residues
Data Source
AI summary
A semiconductor device and a fabrication method thereof are provided. The semiconductor device includes a semiconductor structure, a dielectric layer, a metal-semiconductor compound film and a cover layer. The semiconductor structure has an upper surface and a lateral surface. The dielectric layer encloses the lateral surface of the semiconductor structure and exposes the upper surface of the semiconductor structure. The metal-semiconductor compound film is on the semiconductor structure, wherein the dielectric layer exposes a portion of a surface of the metal-semiconductor compound film. The cover layer encloses the portion of the surface of the metal-semiconductor compound film exposed by the dielectric layer, and exposes the dielectric layer.