CMP Slurry Mixed Surfactant Erosion Control
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) slurries fail to adequately suppress surface erosion during the planarization process of semiconductor manufacturing, particularly when polishing Cu, Ta, and hydrophobic SiOC materials, leading to issues like dishing and in-plane uniformity problems.
Innovation Solution
A CMP slurry comprising abrasive grains and a mixed surfactant system with a first polyether type nonionic surfactant having an HLB value ranging from 3 to 9 and a second polyether type nonionic surfactant with an HLB value ranging from 10 to 20, or a surfactant with a clouding point between 19 to 51°C and another with a clouding point of 55°C or more, which helps in reducing surface erosion and ensuring in-plane uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CMP slurry is used, then polishing speed is maintained, but surface erosion exceeds 20 nm depth
Solution Approach 1:
The patent changes the chemical parameters of the slurry by incorporating specific surfactants with controlled HLB values (3-9 and 10-20) and clouding points (19-51°C and 55°C or higher). This modifies the interfacial properties between slurry, polishing pad, and workpiece surface, enabling erosion control below 20 nm while maintaining process reliability.
Solution Approach 2:
The patent uses a composite surfactant system combining multiple nonionic surfactants with different HLB values and clouding points. This composite approach creates a synergistic effect where the first surfactant (HLB 3-9) provides initial surface modification and the second surfactant (HLB 10-20) enhances erosion control, achieving both precision and reliability.
2Shape
If metal-polishing composition without abrasive grain is used, then Cu film dishing is minimized, but in-plane uniformity deteriorates
Solution Approach 1:
The patent creates a composite polishing system combining abrasive grains with a composite surfactant mixture. The abrasive grains provide mechanical polishing action for in-plane uniformity, while the dual surfactant system (with different HLB values and clouding points) controls chemical interactions to minimize dishing, achieving both shape control and manufacturing precision.
Solution Approach 2:
The patent applies different functional components to different aspects of the polishing process: abrasive grains for mechanical removal and uniformity, while the surfactant mixture with specific HLB ranges provides localized chemical control at the interface to prevent dishing. This local differentiation of functions resolves the contradiction between shape control and uniformity.
3Manufacturing precision
If single surfactant with specific HLB value is used, then erosion is partially suppressed, but erosion suppression is insufficient
Solution Approach 1:
The patent employs a composite surfactant system with two distinct nonionic surfactants having different HLB values (3-9 and 10-20) and different clouding points. This composite structure provides synergistic erosion suppression capability that single surfactants cannot achieve, while maintaining polishing efficiency through the complementary actions of the two surfactants.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: HLB values of surfactants, clouding points, and their concentrations. By carefully selecting surfactants with specific parameter ranges, the patent achieves enhanced erosion suppression without sacrificing polishing productivity, as the dual surfactant system works synergistically to protect the surface while allowing efficient material removal.
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 proposed slurry effectively minimizes surface erosion to less than 20 nm in depth and achieves high polishing speed with improved in-plane uniformity, reducing the occurrence of dishing and scratches, thus enhancing the reliability of semiconductor device manufacturing.
Implementation Method 1
a mixed surfactant comprising a first polyether type nonionic surfactant having an HLB value ranging from 3 to 9 at room temperature, and a second polyether type nonionic surfactant having an HLB value ranging from 10 to 20 at room temperature
Implementation Method 2
a first nonionic surfactant having a clouding point ranging from 19 to 51° C., and a second nonionic surfactant having a clouding point of 55° C. or more
Implementation Method 3
a CMP slurry comprising an abrasive grain
Data Source
AI summary
Disclosed is a CMP slurry comprising an abrasive grain, and a mixed surfactant comprising a first polyether type nonionic surfactant having an HLB value ranging from 3 to 9 at room temperature, and a second polyether type nonionic surfactant having an HLB value ranging from 10 to 20 at room temperature.