Yttrium Sprayed Coating Surface Cleaning to Prevent Etching Dusting
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Solution Overview
Problem
In the semiconductor device fabrication process, yttrium-base particles from coatings can spall off during etching, leading to dusting and reduced yield due to interference with the etching treatment.
Innovation Solution
A yttrium-base sprayed coating is formed by thermally spraying yttrium oxide, yttrium fluoride, or yttrium oxyfluoride, followed by chemical cleaning with an aqueous acid solution to remove particles up to 300 nm in size, ensuring no more than 5 particles/mm² remain on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yttrium oxide, yttrium fluoride, or yttrium oxyfluoride is thermally sprayed to form a corrosion-resistant coating, then corrosion resistance is improved, but yttrium-base particles spall off during etching treatment causing dusting
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution of the spray material (D10≤5μm, D50≤10μm, D90≤20μm) and the coating thickness (50-500μm) to optimize the coating structure. This reduces internal stresses and improves adhesion, preventing particle spalling during etching while maintaining corrosion resistance
Solution Approach 2:
The patent uses composite spray materials containing yttrium oxide, yttrium fluoride, and/or yttrium oxyfluoride with specific compositional ratios (Y2O3: 30-70 wt%, YF3: 10-50 wt%, YOx: 5-20 wt%). This composite composition enhances both corrosion resistance and mechanical integrity, reducing particle spalling
2Reliability
If thermal spraying is used to form yttrium-base coating, then corrosion resistance is improved, but fine particles remain on coating surface interfering with etching treatment
Solution Approach 1:
The patent applies preliminary action by performing surface cleaning treatment before the thermal spraying process. This removes contaminants and prepares the substrate surface, ensuring better adhesion and reducing the presence of fine particles that could interfere with subsequent etching treatment
Solution Approach 2:
The patent controls the spray material particle size parameters (D10≤5μm, D50≤10μm, D90≤20μm) to minimize the formation of fine particles during spraying. The optimized particle size distribution ensures fewer fine particles remain on the coating surface after deposition
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 resulting coating effectively prevents yttrium-base particles from spalling off during etching, reducing dusting and improving the yield of semiconductor device fabrication by maintaining a clean and effective etching environment.
Implementation Method 1
When a coating of yttrium oxide, yttrium fluoride or yttrium oxyfluoride is formed by plasma spraying, a particulate material is melted in a plasma flame into droplets, after which droplets deposit and solidify on a substrate to form a coating
Data Source
AI summary
An yttrium-base sprayed coating is obtained by thermally spraying yttrium oxide, yttrium fluoride or yttrium oxyfluoride onto a substrate to form a coating of 10-500 μm thick, and chemically cleaning the coating with a cleaning liquid of organic acid, inorganic acid or a mixture thereof until the population of particles with a size of up to 300 nm becomes no more than 5 particles/mm2 of the coating surface. The yttrium-base sprayed coating exhibits high corrosion resistance even in a halogen gas plasma atmosphere and prevents yttrium-base particles from spalling off during etching treatment.