Ruthenium Upper Contact for Semiconductor Source/Drain Integrity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in achieving low resistivity for source/drain contacts in field effect transistors, particularly due to issues like breakage and corrosion of metal contacts, which require tight process controls and are not effectively addressed by existing technologies.
Innovation Solution
The use of ruthenium (Ru) as an upper contact material in direct contact with the source/drain contact and interlayer dielectric layers without a conductive barrier layer, combined with a pre-deposition cleaning process using hydrogen and argon plasma, enhances the deposition rate and selectivity, reducing shear stress and corrosion, and improving contact integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal contacts are used for source/drain contacts, then the contacts can be formed with standard materials, but the contacts suffer from breakage and corrosion issues requiring tight process controls
Solution Approach 1:
Ruthenium is introduced as an intermediary material between the cobalt source/drain contact and the interlayer dielectric. This Ru layer acts as a protective mediator that prevents direct interaction between the Co contact and surrounding materials, thereby eliminating corrosion issues and improving contact integrity without requiring tight process controls
Solution Approach 2:
The invention changes the material parameter from conventional metal contacts to ruthenium-based contacts. This material substitution fundamentally alters the chemical and physical properties of the contact, providing inherent resistance to corrosion and breakage while maintaining electrical conductivity
2Productivity
If ruthenium is deposited directly on cobalt surface without pre-treatment, then the process is simpler, but the deposition rate is low and selectivity is poor
Solution Approach 1:
A pre-deposition cleaning process is performed on the cobalt surface before ruthenium deposition. This preliminary action removes surface contaminants and oxides, creating a clean Co surface that enhances the subsequent Ru deposition rate and selectivity, allowing the Ru to preferentially deposit on Co regions
Solution Approach 2:
The pre-deposition cleaning is performed in a plasma environment (inert/reactive atmosphere) that removes surface contaminants without oxidizing the cobalt. This controlled atmospheric condition enables high deposition rate and selectivity by preparing the Co surface while preventing unwanted reactions
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 results in a semiconductor device with reduced shear stress and corrosion issues, achieving higher deposition rates and selectivity for ruthenium on cobalt surfaces, thereby improving the reliability and performance of source/drain contacts.
Implementation Method 1
a pre-deposition cleaning process using hydrogen and argon plasma
Implementation Method 2
a pre-deposition cleaning process using hydrogen and argon plasma
Implementation Method 3
The use of ruthenium (Ru) as an upper contact material in direct contact with the source/drain contact
Data Source
AI summary
A semiconductor device includes a gate electrode, a source/drain structure, a lower contact contacting either of the gate electrode or the source/drain structure, and an upper contact disposed in an opening formed in an interlayer dielectric (ILD) layer and in direct contact with the lower contact. The upper contact is in direct contact with the ILD layer without an interposing conductive barrier layer, and the upper contact includes ruthenium.