Silicon Part Conditioning via Oxidation and Selective Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for conditioning silicon parts in plasma processing chambers face challenges such as surface damage from manufacturing processes, difficulty in controlling etch endpoint, and inefficiencies in removing polymer deposits, leading to wafer defects and poor surface quality.
Innovation Solution
Heating silicon parts to at least 300°C in the presence of oxygen to form a silicon oxide surface, followed by immersion in a hydrofluoric acid (HF) bath that selectively etches silicon oxide, ensuring precise removal of damaged layers and trapped impurities, and potentially repeating the process to enhance surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mixed acid etching is used to remove damaged silicon surfaces, then surface damage is removed, but etch endpoint control is difficult and surface quality is poor
Solution Approach 1:
The patent changes the chemical parameters of the etching process by replacing mixed acid with HF-based solutions. This parameter change enables selective etching of oxidized damaged layers while preserving the underlying silicon surface, solving both the etch endpoint control difficulty and surface quality issues simultaneously
Solution Approach 2:
The patent introduces oxygen as an intermediary substance that oxidizes the damaged silicon surface before etching. This intermediary oxidation step creates a distinct silicon oxide layer that can be selectively removed by HF, providing clear etch endpoint detection and improved surface quality
2Reliability
If polymer deposition is used to address silicon part conditioning, then surface protection is provided, but polymer removal becomes a additional problem
Solution Approach 1:
The patent converts the harmful polymer deposition issue into a beneficial process feature. By using oxygen plasma, the same plasma source that can deposit polymers also provides in-situ oxidation of damaged surfaces. The oxidation process actually helps remove organic contaminants and prepares the surface, turning a potential problem into an advantage
Solution Approach 2:
The patent merges the oxidation step with the plasma processing step. Instead of separate oxidation and cleaning steps, the oxygen plasma simultaneously performs surface oxidation, damaged layer removal preparation, and polymer management in a single integrated process step
3Manufacturing precision
If conventional cleaning methods are used, then general contamination is removed, but damaged silicon surfaces and trapped impurities remain
Solution Approach 1:
The patent uses oxygen plasma as a strong oxidizing environment that rapidly oxidizes damaged silicon surfaces and trapped impurities at temperatures of 200-400°C. This accelerated oxidation effectively removes contaminants that conventional cleaning methods cannot eliminate, achieving superior surface cleanliness
Solution Approach 2:
The patent performs oxidation as a preliminary action before final etching and cleaning steps. By oxidizing the damaged surface first, the subsequent HF etching becomes more effective at removing the oxidized damaged layers and trapped impurities, simplifying the overall process while achieving better results
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 effectively scavenges and removes damaged silicon surfaces with high precision, preventing wafer defects and allowing for the realization of smaller hole sizes with reduced risk of dimension blow-up, while also addressing the limitations of mixed acid etching and polymer deposition issues.
Implementation Method 1
The silicon part is heated to a temperature of at least 300° C. in the presence of oxygen to form an outer surface of the silicon part into silicon oxide
Implementation Method 2
The silicon part is placed in a HF wet bath, wherein the HF bath selectively etches silicon oxide with respect to silicon
Data Source
AI summary
A method for conditioning and cleaning a silicon part is provided. The silicon part is heated to a temperature of at least 300° C. in the presence of oxygen to form an outer surface of the silicon part into silicon oxide. The silicon part is placed in a wet bath wherein the bath is a solution that selectively etches silicon oxide with respect to silicon.