Source/Drain Contact Via Structure for Low-Resistance Silicide Contacts
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Solution Overview
Problem
The shrinking sizes of integrated circuits highlight the importance of contact resistance, particularly between source/drain silicide regions and overlying contact vias, which existing technologies have not adequately addressed, leading to performance limitations in semiconductor devices.
Innovation Solution
A source/drain contact via is formed using a silicide layer, a first metallic portion, and a glue layer, where the first metallic portion is spaced apart from a second metallic portion by the glue layer, utilizing PVD deposition to protect the silicide layer from CVD process damage and improve adhesion between the contact via and the hard mask layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CVD deposition process is used to form the contact via, then the filling capability is improved, but the silicide layer is damaged
Solution Approach 1:
A protective layer is formed over the silicide layer before the CVD deposition process. This preliminary protective action prevents the silicide layer from damage during the subsequent CVD filling process, allowing the CVD process to be used without compromising silicide layer integrity.
Solution Approach 2:
The protective layer acts as an intermediary between the CVD deposition process and the silicide layer. It enables the CVD process to proceed while isolating the silicide layer from harmful effects, thus resolving the contradiction between filling capability and layer integrity.
2Reliability
If PVD deposition process is used to form the first metallic portion, then the silicide layer is protected from damage, but the adhesion with hard mask layer is reduced
Solution Approach 1:
The contact via structure is segmented into multiple portions: a first metallic portion formed by PVD that protects the silicide layer, and a second metallic portion formed by CVD that provides adhesion. This segmentation allows each portion to be optimized for its specific function, resolving the contradiction between protection and adhesion.
Solution Approach 2:
Different deposition methods are used for different portions of the contact via. The first metallic portion uses PVD for protection, while the second metallic portion uses CVD for adhesion. This local quality approach ensures that each region has the properties needed for its specific function.
3Reliability
If continuous metal layer is used in contact via, then the electrical conductivity is improved, but the adhesion to hard mask layer is reduced
Solution Approach 1:
The continuous metal layer is segmented into two separate metallic portions with a glue layer in between. The first metallic portion provides electrical conductivity and silicide layer protection, while the second metallic portion provides adhesion to the hard mask layer. The glue layer acts as an adhesive bridge, maintaining electrical connectivity while enabling adhesion.
Solution Approach 2:
The glue layer serves as an intermediary between the two metallic portions. It enables the second metallic portion to adhere to the hard mask layer while maintaining electrical continuity with the first metallic portion, thus resolving the contradiction between conductivity and adhesion.
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 configuration reduces silicide layer damage and enhances the reliability of the source/drain contact via, thereby improving the performance of transistors by addressing the contact resistance issues.
Implementation Method 1
by using a PVD deposition process to form the first metallic portion on the silicide layer
Implementation Method 2
the CVD deposition process subsequently
Data Source
AI summary
A semiconductor device and a method of manufacturing thereof are provided. The semiconductor device comprises a gate stack, source/drain regions, and a source/drain contact via. The gate stack is disposed on a substrate. The source/drain regions are disposed on the substrate and located at opposite sides of the gate stack. The source/drain contact via penetrates through the substrate and is electrically connected to a first source/drain region among the source/drain regions. The source/drain contact vias comprise a first conductor and a second conductor disposed on the first conductor. The first conductor comprises a silicide layer and a first metallic portion. The second conductor comprises a glue layer and a second metallic portion. The first metallic portion is spaced apart from the second metallic portion by the glue layer.