Ruthenium Layer Planarization via Ion Implant Doping
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Solution Overview
Problem
Ruthenium metal is difficult to planarize using conventional chemical mechanical polishing (CMP) slurries, leading to long polishing times and potential damage to surrounding materials due to strong oxidizers, and requires precise pH control to prevent toxic byproducts.
Innovation Solution
An ion implant method is employed to dope ruthenium metal with carbon, boron, phosphorous, oxygen, silicon, argon, germanium, arsenic, or xenon ions, adjusting implant energy (0.3 keV to 50 keV) and angle (0° to 80°) to increase polishing rate, followed by CMP to remove doped ruthenium faster.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong oxidizers are used in CMP to planarize 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 composition parameters of the CMP slurry by incorporating specific weak oxidizers (potassium ferricyanide, potassium ferrocyanide, sodium hypochlorite) and complexing agents (EDTA, citric acid) to achieve effective ruthenium polishing without the need for strong oxidizers, thereby avoiding damage to surrounding materials and toxic byproduct generation
Solution Approach 2:
The patent introduces complexing agents as intermediaries that facilitate the polishing process by forming complexes with ruthenium, enabling effective removal through weak oxidizers rather than requiring strong oxidizers directly, thus mediating between the polishing requirement and the avoidance of harmful effects
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 optimizes the chemical parameters of the CMP slurry including pH (maintained between 8-10.5), oxidizer concentration, and complexing agent concentration to achieve fast and complete polishing within 1-5 minutes, preventing excessive polishing time and associated damage to surrounding materials
Solution Approach 2:
The patent employs a balanced chemical system where the complexing agents and weak oxidizers work synergistically to provide controlled and uniform polishing rates, ensuring complete planarization is achieved without over-polishing or damage to surrounding structures
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 method enhances ruthenium polishing rate by 1.1 to 1.7 times, reducing polishing time and minimizing damage to surrounding materials while maintaining planarization efficiency.
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
Implementation Method 2
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.