Molybdenum CMP Composition With High Removal and Low Etching
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) compositions for molybdenum surfaces lack the ability to achieve high removal rates while maintaining low etching rates and appropriate selectivity, particularly for molybdenum and tetraethyl orthosilicate (TEOS) layers in semiconductor manufacturing.
Innovation Solution
A CMP composition comprising abrasive grains, a molybdenum removal rate enhancer (basic amino acid), a TEOS removal rate enhancer (ammonium salt), an oxidizer (peroxide), and water, formulated at a pH of less than 6, to enhance polishing efficiency and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP compositions are used for molybdenum polishing, then the polishing process can be performed, but the removal rate is insufficient and etching rate control is poor
Solution Approach 1:
The patent changes the chemical parameters of the CMP composition by introducing specific additives: basic amino acids (such as arginine, lysine, or histidine) as molybdenum removal rate enhancers, and ammonium salts (such as ammonium sulfate, ammonium nitrate, ammonium acetate, or ammonium citrate) as TEOS removal rate enhancers. The composition is formulated at a controlled pH of less than 6, which optimizes the chemical reactions for high removal rates while controlling etching.
Solution Approach 2:
The patent creates a composite polishing composition that combines multiple functional components: abrasive grains (such as colloidal silica), basic amino acids, ammonium salts, peroxide oxidizer, and water. This composite formulation synergistically combines mechanical abrasion with enhanced chemical removal mechanisms, achieving both high removal rates and controlled etching through the interaction of different material components.
2Productivity
If polishing composition is applied to remove excess molybdenum, then material removal is achieved, but selectivity between molybdenum and other materials deteriorates
Solution Approach 1:
The patent applies local quality by using basic amino acids that specifically target molybdenum surfaces through chemical affinity, while ammonium salts specifically enhance TEOS removal. This localized chemical action at different material interfaces provides high selectivity: the amino acids interact preferentially with molybdenum, and the ammonium salts interact preferentially with TEOS, enabling selective removal without affecting other materials.
Solution Approach 2:
The controlled pH parameter (less than 6) creates optimal conditions for the selective chemical reactions between the additives and specific materials. The acidic pH environment activates the basic amino acids and ammonium salts to exhibit their respective selective removal properties, enhancing molybdenum and TEOS removal rates while maintaining selectivity against other materials in the semiconductor structure.
3Productivity
If high removal rate polishing is performed, then productivity increases, but etching damage to the substrate increases
Solution Approach 1:
The basic amino acids and ammonium salts act as intermediary substances that facilitate material removal through controlled chemical reactions. These intermediaries convert the mechanical polishing process into a more controlled chemical-mechanical process, where the additives mediate between the abrasive action and the substrate, enabling high removal rates through chemical dissolution while protecting the substrate from excessive etching damage.
Solution Approach 2:
The peroxide oxidizer component changes the chemical state of the polishing environment, creating oxidized species that enhance material removal through chemical reactions. This parameter change in the chemical environment allows the polishing process to achieve high removal rates through oxidative dissolution while the controlled pH and additive concentrations prevent uncontrolled etching of the substrate.
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 composition achieves high molybdenum removal rates with low etching rates and high TEOS removal rates, maintaining a favorable molybdenum to etching rate ratio, thereby improving the polishing process for semiconductor substrates.
Implementation Method 1
the oxidizer is a peroxide
Implementation Method 2
the abrasive grains are a sulfonic acid-modified colloidal silica
Data Source
AI summary
The present disclosure relates to chemical mechanical polishing (CMP) compositions for polishing molybdenum surfaces.In particular, the CMP composition includes abrasive grains, a molybdenum (Mo) removal rate enhancer, a TEOS removal rate enhancer, an oxidizer, and water, combined in specified amounts to provide a composition with advantageous properties such as high Mo and TEOS removal rates while maintaining high Mo (RR) removal rate:Mo (ER) etching rate selectivity.