Etching Chamber Coating for Aluminum Fluoride Particle Removal
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Solution Overview
Problem
The formation of aluminum fluoride (AlF) particles during the etching of metal layers in dry etching chambers leads to these particles adhering to the chamber surfaces, which can break and fall onto wafers, causing manufacturing yield loss due to their weak bonding and high vaporizing temperature, making them difficult to remove.
Innovation Solution
A coating layer is deposited in the etching chamber, comprising silicon-based materials that bond with metal particles, preventing them from falling onto wafers, and a gas-flow re-distributor is used to ensure uniform gas flow, reducing back-stream and particle deposition. The coating layer is then removed along with the particles, utilizing specific etching gases and processes to effectively clean the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aluminum is etched using fluorine ions, then etching of metal layer is achieved, but aluminum fluoride particles are formed and adhere to chamber surfaces
Solution Approach 1:
A coating layer is deposited on the chamber surface to act as an intermediary between the aluminum fluoride particles and the chamber wall. This coating layer has high affinity for aluminum fluoride, causing particles to adhere to it rather than the chamber surface, preventing particle contamination of wafers while maintaining etching productivity
2Object-generated harmful factors
If aluminum fluoride particles are removed by heating, then particles can be eliminated, but high energy consumption is required due to high vaporizing temperature
Solution Approach 1:
Instead of using thermal energy to vaporize aluminum fluoride particles at high temperature, the patent changes the removal mechanism to chemical etching. Specific etching gases are introduced that react with aluminum fluoride at lower temperatures, selectively removing particles without requiring high energy input for vaporization
3Reliability
If coating layer is deposited to trap particles, then particle adhesion to wafers is prevented, but additional process steps and time are required
Solution Approach 1:
The coating layer is deposited in advance before the etching process begins. This preliminary action ensures that the chamber surface is prepared to capture aluminum fluoride particles during etching, preventing particle contamination of wafers without requiring additional time during the main etching process cycle
4Object-generated harmful factors
If gas flow is increased to prevent particle deposition, then particle formation is reduced, but back-stream and uniformity issues arise
Solution Approach 1:
The coating layer serves as an intermediary that captures aluminum fluoride particles regardless of gas flow variations. This eliminates the need to optimize gas flow rates to prevent particle deposition, allowing uniform gas flow distribution without causing back-stream or compromising manufacturing precision
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
This method significantly improves manufacturing yield by adhering metal particles to the coating layer, preventing them from falling on wafers and ensuring thorough removal, thus addressing the issue of particle-induced yield loss.
Implementation Method 1
A coating layer is deposited in the etching chamber, comprising silicon-based materials that bond with metal particles
Implementation Method 2
In the etching process, plasma is generated from the etching gases
Implementation Method 3
plasma is generated from the etching gases
Implementation Method 4
The metal ions in the metal layer may sometimes react with the ions in the etching gases to form particles. For example, when aluminum is etched, the aluminum ions may react with fluorine ions to form aluminum fluorine (AlF) particles
Data Source
AI summary
A method includes forming a coating layer in a dry etching chamber, placing a wafer into the dry etching chamber, etching a metal-containing layer of the wafer, and moving the wafer out of the dry etching chamber. After the wafer is moved out of the dry etching chamber, the coating layer is removed.