Wafer Meniscus Stability via Gap Monitoring and Recipe Control
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Solution Overview
Problem
In the semiconductor chip fabrication industry, existing drying techniques for wafers often result in the formation of droplets and subsequent contaminants due to breakdowns in the moving liquid/gas interface during cleaning and drying processes, leading to defects in devices.
Innovation Solution
A system that monitors and maintains meniscus stability using orientation monitor signals and calibration data to ensure a continuous meniscus configuration across the gap between the fluid emitter and the wafer surface, adjusting process parameters as needed to prevent meniscus separation and droplet formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional drying techniques (spin-drying, IPA, Marangoni drying) are used to remove cleaning fluid quickly, then drying speed is improved, but the moving liquid/gas interface breaks down causing droplet formation and contaminant residues
Solution Approach 1:
The system uses orientation monitor signals to detect the position and stability of the meniscus in real-time, providing feedback to the control system. This feedback mechanism allows the system to adjust process parameters dynamically to maintain meniscus stability while achieving fast drying speeds, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The patent employs recipe-controlled process parameters that can be adjusted based on meniscus stability requirements. By changing parameters such as fluid flow rate, emitter positioning, and processing speed within controlled ranges, the system maintains a stable meniscus configuration throughout the drying process, preventing interface breakdown while achieving efficient drying.
2Manufacturing precision
If the moving liquid/gas interface is maintained to prevent droplet formation, then contaminant residue is reduced, but processing speed and efficiency are limited
Solution Approach 1:
Real-time monitoring of meniscus orientation provides continuous feedback on interface stability. This allows the system to operate at higher speeds while maintaining precision control over the liquid/gas interface, ensuring surface cleanliness is not compromised by increased processing speed.
Solution Approach 2:
The system transitions from static to dynamic control by continuously adjusting process parameters based on real-time meniscus position data. This dynamic adaptation enables the system to maintain a stable moving interface at higher processing speeds, simultaneously achieving surface cleanliness and improved productivity.
3Reliability
If meniscus processing is monitored and adjusted to maintain stability, then droplet formation is prevented, but system complexity increases
Solution Approach 1:
The patent replaces complex mechanical monitoring and adjustment mechanisms with optical sensing (orientation monitor signals) and electronic control systems. This substitution reduces mechanical complexity while achieving reliable meniscus stability through non-contact measurement and electronic parameter adjustment.
4Reliability
If calibration data and recipe control are implemented to maintain meniscus stability, then processing reliability is improved, but setup and operation complexity increase
Solution Approach 1:
The system incorporates automated recipe selection and parameter adjustment based on calibration data, allowing the processing system to self-regulate meniscus stability. This reduces the need for manual intervention and complex operator decisions, making the system easier to operate while maintaining high reliability through automated control.
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 effectively prevents contaminants from remaining on the wafer surface by maintaining a stable meniscus configuration during processing, even with larger wafer diameters and increased processing speeds, thereby reducing defects and allowing for more efficient cleaning.
Implementation Method 1
Meniscus monitors are configured to separately receive a return laser beam from each respective opposite side of a wafer carrier for generating a separate orientation monitor signal representing the relative orientation of the wafer surface and a fluid emitter surface at the respective side
Data Source
AI summary
Methods for monitoring meniscus processing of a wafer surface to stabilize a meniscus are provided. In one example, the processing is in response to a current recipe that defines a desired gap between the wafer surface and a proximity head. The method includes the operations of monitoring current meniscus processing to determine that a current gap is other than the desired gap, and identifying a calibration recipe that specifies the current gap. The method then continues the meniscus processing of the wafer surface using process parameters specified by the identified calibration recipe.