Substrate Processing Humidity Segmentation for Etching Stability
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Solution Overview
Problem
Conventional substrate processing methods face issues with the repeated use of etching and polymer removal liquids, leading to increased etching rates, particle formation, and watermark generation due to humidity changes and moisture evaporation during the processing of semiconductor wafers.
Innovation Solution
A substrate processing method and apparatus that utilize a first gas with higher humidity for processing and a second gas with lower humidity for drying, preventing moisture evaporation and reducing particle and watermark formation, while allowing for the reuse of etching and polymer removal liquids without degradation in processing ability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the chamber is dried throughout all processing steps to prevent watermarks, then drying quality is improved, but the concentration of process liquid increases due to moisture evaporation, worsening etching rate control
Solution Approach 1:
The processing steps are segmented into two distinct humidity environments: the first gas (higher humidity) is used during etching and rinsing steps to prevent process liquid concentration changes, while the second gas (lower humidity) is used specifically during the drying step to ensure high-quality drying results without affecting process liquid concentration
Solution Approach 2:
The humidity parameter of the chamber atmosphere is dynamically changed between processing steps by switching between the first gas and second gas. The first gas maintains higher humidity to prevent moisture evaporation from process liquid, while the second gas provides lower humidity for effective drying, thus resolving the contradiction between drying quality and etching rate control
2Manufacturing precision
If dehumidified air is supplied throughout all steps to prevent watermarks, then particle generation is reduced, but moisture evaporation from process liquid increases, worsening processing consistency
Solution Approach 1:
The processing sequence is divided into distinct phases with different atmospheric requirements: etching and rinsing phases use the first gas to maintain process liquid stability, while the drying phase uses the second gas to prevent particle generation and watermarks, thus resolving the contradiction between surface quality and process liquid composition stability
Solution Approach 2:
The chamber atmosphere is prepared with the first gas before etching and rinsing operations to prevent moisture evaporation, and then switched to the second gas before the drying step to prevent particle generation, ensuring both process liquid stability and high surface quality
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 approach maintains the processing ability of etching and polymer removal liquids when reused, prevents excessive etching, and reduces particle and watermark formation on the substrate surface, ensuring consistent and improved drying performance.
Implementation Method 1
moisture contained in the HF liquid or the like is evaporated with the repeated usage of the HF liquid or the like
Implementation Method 2
moisture (steam) in the chamber is dissolved in the IPA liquid which is supplied onto the surface of the wafer in the drying step
Data Source
AI summary
At first, with a chamber being filled with a first gas, a process liquid is supplied onto a surface of a wafer in the chamber so as to process the surface of the wafer. At this time, the process liquid discharged from the chamber is returned to a process-liquid supplying part. Thereafter, with the chamber being filled with a second gas whose humidity is lower than that of the first gas, a fluid for forming a liquid film is supplied onto the surface of the wafer in the chamber to form a liquid film on the surface of the wafer and to dry the surface of the wafer.