Ion Implantation for Ruthenium Planarization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ruthenium metal is difficult to planarize using existing chemical mechanical polishing (CMP) slurries, requiring strong oxidizers and long polishing times, which can damage surrounding materials and result in toxic byproducts.
Innovation Solution
An ion implant method is employed to increase the polishing rate of ruthenium metal by introducing dopants such as carbon, boron, phosphorous, oxygen, silicon, argon, germanium, arsenic, or xenon at specific energies and angles, inducing defects that accelerate oxidation and facilitate faster polishing during the CMP process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong oxidizers are used in CMP slurry to polish ruthenium metal, then the polishing capability is improved, but surrounding materials are damaged and toxic byproducts are generated
Solution Approach 1:
The patent changes the chemical parameters of the CMP slurry by replacing strong oxidizers with a mild oxidizing environment. This is achieved through specific pH control (maintaining pH between 8-10) and using alternative polishing chemistries that do not rely on aggressive oxidizing agents, thereby reducing harm to surrounding materials while maintaining polishing effectiveness
Solution Approach 2:
The patent introduces a sacrificial ruthenium layer that is deliberately deposited over the ruthenium metal to be polished. This sacrificial layer consumes the polishing action and protects the underlying structure, allowing the use of milder polishing conditions that don't require strong oxidizers, thus eliminating the need for harmful chemicals
2Manufacturing precision
If long polishing times are used to planarize ruthenium metal, then the polishing completeness is improved, but the damage to surrounding materials increases
Solution Approach 1:
The patent performs preliminary preparation by depositing a sacrificial ruthenium layer before the actual polishing process. This pre-preparation step sets up a controlled system where the polishing action can be directed specifically at the sacrificial layer, enabling complete planarization in shorter times without exposing surrounding materials to prolonged harmful conditions
Solution Approach 2:
The sacrificial ruthenium layer acts as an intermediary between the polishing slurry and the underlying ruthenium metal structure. It absorbs the polishing action and chemical exposure, mediating the interaction to protect the final structure from damage while still achieving the desired planarization
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 ion implantation method enhances the polishing rate of ruthenium metal by 1.1 to 1.7 times, reducing polishing time and minimizing damage to surrounding materials, while maintaining control over implant depth and dopant distribution to prevent material compromise.
Implementation Method 1
An ion implant method is employed to increase the polishing rate of ruthenium metal by introducing dopants such as carbon, boron, phosphorous, oxygen, silicon, argon, germanium, arsenic, or xenon at specific energies and angles, inducing defects that accelerate oxidation and facilitate faster polishing during the CMP process
Data Source
AI summary
The present disclosure describes a method for the planarization of ruthenium metal layers in conductive structures. The method includes forming a first conductive structure on a second conductive structure, where forming the first conductive structure includes forming openings in a dielectric layer disposed on the second conductive structure and depositing a ruthenium metal in the openings to overfill the openings. The formation of the first conductive structure includes doping the ruthenium metal and polishing the doped ruthenium metal to form the first conductive structure.