Dielectric CMP Composition for Tungsten Etching Inhibition
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) compositions struggle to achieve high selectivity in removing dielectric materials over tungsten and cobalt while maintaining high surface quality and stability, leading to unwanted etching and surface defects.
Innovation Solution
A dielectric polishing composition comprising surface-modified colloidal silica particles with a negative charge, guanidine derivatives, polyacrylamides, iron (III) oxidizer, phosphoric acid, and stabilizers, formulated at a pH of 2.0 to 4.5, to enhance silicon oxide and silicon nitride removal rates while minimizing tungsten and cobalt etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etch selectivity methods are used to protect tungsten from over-etching, then tungsten etching inhibition is achieved, but silicon etching rate is reduced and process complexity increases
Solution Approach 1:
A dedicated etch inhibition layer is introduced as an intermediary component between the silicon layer and the etchant. This layer selectively absorbs or blocks the etchant to protect tungsten features while allowing silicon etching to proceed at normal rates, thereby resolving the contradiction between tungsten protection and silicon etching efficiency
Solution Approach 2:
The etch inhibition layer is applied locally only in regions where tungsten protection is needed, rather than uniformly across the entire substrate. This localized application maintains high silicon etching rates in areas without tungsten while providing targeted protection where required
2Reliability
If conventional etch selectivity methods are used to protect tungsten, then tungsten etching inhibition is achieved, but manufacturing process complexity increases
Solution Approach 1:
The etch inhibition layer formation is merged with existing manufacturing steps such as spacer deposition or mandrel formation, eliminating the need for separate process steps. This integration reduces overall process complexity while maintaining effective tungsten protection
Solution Approach 2:
The etch inhibition layer serves multiple functions simultaneously: it protects tungsten from over-etching, acts as a spacer definition layer, and can serve as a mandrel for subsequent patterning steps. This multi-functionality reduces the number of separate layers and processes needed
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 provides high selectivity and stability, ensuring effective removal of dielectric layers with minimal etching of tungsten and cobalt, maintaining surface quality and preventing phase separation or agglomeration.
Implementation Method 1
compositions and methods for tungsten etching inhibition
Data Source
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AI summary
The presently claimed invention relates to dielectric polishing composition and methods thereof. The presently claimed invention particularly relates to a composition comprising: (A) surface - modified colloidal silica particles comprising a negatively - charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of from 60 nm to 200 nm, and a zeta potential < -35 mV at a pH in the range of from ≥ 2.0 to ≤ 4.5; (B) first corrosion inhibitor selected from at least one guanidine derivative; (C) second corrosion inhibitor selected from polyacrylamides or polyacrylamide copolymers; (D) at least one iron (III) oxidizer; (E) at least one silicon oxide removal rate enhancer selected from phosphoric acid and salts thereof; (F) at least one stabilizer; and (G) an aqueous medium, wherein the pH of the composition is in the range of from ≥ 2.0 to ≤ 4.5.