Functionalized CMP Slurry for Tungsten Recess Control
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Solution Overview
Problem
Conventional chemical mechanical polishing compositions for tungsten etching in semiconductor manufacturing often cause recessing of tungsten vias, leading to electrical contact issues and increased nonplanarity, due to their harsh chemical etching action, which is not effectively addressed by existing compositions.
Innovation Solution
A chemical mechanical polishing solution comprising functionalized carbon-based particles with oxygen-containing functional groups, a silica abrasive, and a Fenton's catalyst or reagent, along with a corrosion inhibitor, is used to enhance polishing and planarization of metal and metal nitride layers, providing controlled removal rates and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Fenton's reagent with alumina or silica abrasive is used for tungsten polishing, then chemical etching action enhances removal rate, but tungsten recessing and keyholing occur
Solution Approach 1:
The invention changes the chemical parameters of the polishing composition by introducing a corrosion inhibitor that forms a protective film on tungsten, modifying the chemical interaction from aggressive etching to controlled removal, thereby preventing recessing while maintaining adequate removal rate
Solution Approach 2:
The corrosion inhibitor acts as an intermediary substance that mediates between the abrasive particles and tungsten surface, forming a protective film that prevents direct harmful chemical etching while allowing mechanical abrasion to proceed effectively
2Productivity
If harsh oxidizing environment with acidic pH below 3.5 is used, then chemical etching of tungsten is enhanced, but electrical contact problems and nonplanarity increase
Solution Approach 1:
The invention converts the harmful harsh oxidizing environment into a beneficial controlled process by adding corrosion inhibitor that selectively protects tungsten, transforming the aggressive chemical action into a controlled removal mechanism that maintains reliability
Solution Approach 2:
The invention modifies the chemical environment parameters by introducing corrosion inhibitor that alters the interaction between acidic oxidizing agents and tungsten, changing the process from harmful etching to controlled, reliable removal
3Productivity
If conventional polishing composition is used to achieve desired polishing rates, then metal removal is effective, but selectivity to dielectric layers deteriorates
Solution Approach 1:
The corrosion inhibitor serves as an intermediary that selectively protects dielectric layers while allowing metal removal to proceed, creating a differential action that maintains both polishing rate and selectivity
Solution Approach 2:
The invention applies local quality protection through corrosion inhibitor that selectively forms protective films on specific materials (dielectrics and tungsten), enabling differential removal rates that maintain selectivity while achieving effective metal polishing
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 solution achieves effective removal rates of metals like cobalt, copper, molybdenum, and tungsten, while minimizing defects and maintaining planarity, with improved selectivity to dielectric layers, reducing recessing and keyholing issues.
Implementation Method 1
functionalized carbon-based particles having oxygen-containing functional groups react with a peroxy moiety to increase oxygen to carbon atomic ratio
Implementation Method 2
Fenton's catalyst or reagent
Implementation Method 3
silica abrasive
Implementation Method 4
corrosion inhibitor
Data Source
AI summary
The invention provides a chemical mechanical polishing solution for metal and metal nitride substrates. The polishing solution includes a solvent; functionalized carbon-based particles having oxygen-containing functional groups a silica abrasive; a Fenton's catalyst or reagent and a corrosion inhibitor. The functionalized carbon-based particles have oxygen-containing functional groups that react with a peroxy moiety to increase oxygen to carbon atomic ratio on the functionalized carbon-based particles. The functionalized carbon-based particles contain at least 10 weight percent of an sp3-containing structure, the functionalized carbon-based particles include at least 0.01 atomic percent oxygen and a surface of the functionalized carbon-based particles has an atomic oxygen to carbon ratio of at least 0.01.