Bevel Plasma Blocking Layer for Silicidation Contamination
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Solution Overview
Problem
The formation of a metal silicide layer in the wafer bevel region during the silicidation process leads to contamination of the etching machine and reduces the reliability and yield of semiconductor fabrication processes.
Innovation Solution
A blocking layer, such as a silicon dioxide layer, is formed only in the wafer bevel region using bevel plasma treatment before the metal silicidation process, preventing the formation of a metal silicide layer in this region and thereby avoiding contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal silicide layer is formed during the silicidation process, then contact resistance is reduced, but contamination occurs in the etching machine chamber
Solution Approach 1:
The patent applies local quality by forming a blocking layer selectively only in the wafer bevel region, while leaving the active device regions uncovered. This localized approach prevents metal silicide formation only where it causes contamination (bevel region), while allowing it in regions where it provides benefit (contact regions), thus resolving the contradiction between reducing contact resistance and preventing contamination
Solution Approach 2:
The blocking layer acts as an intermediary substance that prevents direct contact between the metal layer and the silicon surface in the bevel region. This intermediary layer blocks the formation of metal silicide in the bevel region while allowing the silicidation process to proceed normally in the active regions, thereby preventing contamination without affecting contact resistance
2Object-affected harmful factors
If a blocking layer is formed in the wafer bevel region, then contamination is prevented, but process complexity increases
Solution Approach 1:
The blocking layer is formed in advance before the metal silicide formation process, specifically targeting the wafer bevel region. This preliminary action prevents the need for complex contamination removal procedures later, and the blocking layer formation integrates smoothly into the existing process flow, adding minimal complexity while effectively preventing contamination
Solution Approach 2:
The patent utilizes parameter changes in the plasma treatment process (such as gas composition, power, and time) to achieve selective blocking layer formation only in the bevel region. By optimizing these parameters, the process achieves the desired selectivity without requiring additional process steps, thereby minimizing the increase in 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 effectively prevents metal silicide layer formation in the wafer bevel region, improving the reliability and yield of the semiconductor fabrication process by reducing contamination in the etching machine.
Implementation Method 1
a bevel plasma treatment is performed on the semiconductor wafer to form a blocking layer only in the wafer bevel region
Implementation Method 2
a bevel plasma treatment is performed on the semiconductor wafer to form a blocking layer only in the wafer bevel region
Data Source
AI summary
A method for fabricating a semiconductor structure on a semiconductor wafer is disclosed. A semiconductor wafer having a first region, a second region, and a wafer bevel region is provided. The wafer bevel region has a silicon surface. A first semiconductor structure is formed in the first region and a second semiconductor structure is formed in the second region. The semiconductor wafer is subjected to a bevel plasma treatment to form a blocking layer only in the wafer bevel region. A silicidation process is then performed to form a silicide layer only in the first region and the second region.