Wet Bench In-Situ Pre-Treatment for Wafer Cross-Contamination
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Solution Overview
Problem
Cross contamination during wet bench processing of semiconductor wafers leads to defects, necessitating a solution to improve yield and reduce contamination.
Innovation Solution
An in-situ pre-treatment process is performed in an ONB tank prior to wet bench operations, including pre-cleaning and/or pre-heating to remove organic contamination and stabilize wafer temperature, using solutions like IPA or SC1, and high-temperature deionized water to prepare wafers before immersion in CHB tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batches of wafers are processed simultaneously in a tank during wet bench process, then productivity is improved, but cross contamination occurs causing defects
Solution Approach 1:
The patent applies preliminary action by performing pre-treatment operations (pre-cleaning and pre-heating) on wafers before they enter the main wet bench processing tanks. This prepares the wafers in advance to resist cross-contamination during batch processing, allowing larger batch sizes while maintaining cleanliness. The pre-treatment modifies the wafer surface state beforehand, creating a protective condition that prevents harmful cross-contamination effects during subsequent batch processing.
2Device complexity
If conventional wet bench processing is used without pre-treatment, then device complexity is reduced, but manufacturing precision deteriorates due to cross contamination
Solution Approach 1:
The patent applies segmentation by dividing the wet bench processing into distinct segments: a pre-treatment segment (pre-cleaning and pre-heating in separate tanks) followed by the main processing segment. This segmentation isolates the critical cleanliness-preparation steps from the main batch processing, allowing each segment to be optimized independently. The pre-treatment segment specifically addresses manufacturing precision by removing contaminants before wafers enter the main processing tanks, while the main segment maintains productivity through efficient batch processing.
3Use of energy by moving object
If wafer temperature is not stabilized before processing, then energy consumption is reduced, but etch rate stability deteriorates
Solution Approach 1:
The patent applies preliminary action by implementing a pre-heating step before the main wet bench processing. This pre-heating stabilizes the wafer temperature in advance, ensuring that when wafers enter the etching tanks, their temperature is already controlled and uniform. This preliminary temperature stabilization prevents etch rate variations during processing, maintaining manufacturing precision without requiring excessive energy during the main processing phase, as the thermal conditioning is already complete.
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
Reduces cross-contamination and defects, enhances yield by allowing larger batch sizes and stabilizes etch rates through improved temperature control.
Implementation Method 1
pre-cleaning and/or pre-heating to remove organic contamination
Implementation Method 2
pre-cleaning and/or pre-heating to remove organic contamination and stabilize wafer temperature, using solutions like IPA or SC1, and high-temperature deionized water
Data Source
AI summary
Embodiments of the present disclosure relates to a wet bench processing including an in-situ pre-treatment prior to performing the first set of wet bench operations. The pre-treatment may include a pre-clean operation and/or a pre-heat operation. The pre-treatment may be performed in one of the existing ONB tanks without requiring adding new tanks to an existing wet bench tool. The pre-clean operation removes particles from a batch of wafers to avoid or reduce cross-contamination and defect issues, thus improving the yield rate of the wet bench process. The pre-heat operation provides better control and stabilize the temperature in the CHB tank to stabilize the process, such as to stabilize an etch rate.