Wafer Drying Flow Stability via Dynamic Gas-Liquid Interface Control
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Solution Overview
Problem
In semiconductor wafer processing, achieving stable flow between a drying gas and a cleaning liquid is challenging, leading to flow instability, air bubbles, and incomplete drying, which can affect subsequent processing steps.
Innovation Solution
A method of flow control is implemented, where a liquid is injected onto a wafer via a dispense system with a plate and injection holes. A drying gas is then injected to push out the liquid, and parameters such as inlet flow pressure, distance, and injection sequence are adjusted to maintain a stable interface between the drying gas and the liquid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drying gas is injected to push out liquid quickly, then drying speed is improved, but flow instability occurs leading to air bubbles and incomplete drying
Solution Approach 1:
The patent applies dynamics by making the injection system adjustable rather than fixed. The plate distance from the wafer and the inlet flow pressure are dynamically adjusted during the drying process. Specifically, the plate is positioned at an optimized distance (e.g., 1-10 mm) from the wafer surface, and the inlet flow pressure is controlled to maintain a stable interface between drying gas and liquid, preventing flow instability while achieving efficient drying.
Solution Approach 2:
The patent employs parameter changes by optimizing key process parameters including plate distance, inlet flow pressure, and injection sequence. By carefully selecting and adjusting these parameters, the system achieves a stable gas-liquid interface during the drying process. For example, the inlet flow pressure is controlled to be within a specific range, and the plate distance is optimized to balance drying speed and flow stability, thereby preventing air bubble formation while maintaining high drying efficiency.
2Reliability
If inlet flow pressure is increased to maintain stable interface, then flow stability is improved, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by optimizing the inlet flow pressure to the minimum necessary level to maintain interface stability. Rather than using excessively high pressure, the system carefully controls the pressure within an optimized range that achieves stable drying gas-liquid interface while minimizing energy consumption. This optimized parameter selection balances interface stability requirements with energy efficiency.
Solution Approach 2:
The patent employs self-service by designing a system that automatically maintains stable interface through optimized parameter selection. The carefully selected plate distance and inlet flow pressure parameters allow the system to self-regulate the gas-liquid interface stability without requiring excessive energy input or complex active control mechanisms, achieving energy-efficient stable drying.
3Manufacturing precision
If plate distance is reduced to improve flow control, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by using an adjustable plate position rather than a fixed position. The plate can be positioned at an optimized distance (e.g., 1-10 mm) from the wafer surface, allowing flexible adjustment to achieve precise flow control. This dynamic positioning capability enables fine-tuned control over the drying gas flow pattern and gas-liquid interface stability without requiring overly complex fixed structures.
Solution Approach 2:
The patent employs parameter changes by optimizing the plate distance parameter to achieve the desired flow control precision. By selecting an appropriate plate distance (e.g., 1-10 mm from wafer surface), the system achieves precise control over the drying process and gas-liquid interface behavior. This optimized parameter selection delivers high manufacturing precision while avoiding the need for excessively complex device structures.
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 ensures a stable and uniform interface, preventing flow instability and promoting faster, more efficient drying of semiconductor wafers, thereby improving the reliability of subsequent processing steps.
Implementation Method 1
A drying gas is injected onto the wafer via the dispense system to push out the liquid
Implementation Method 2
γ is a surface tension of the liquid
Implementation Method 3
μ1 is a viscosity of the drying gas. μ2 is a viscosity of the liquid
Implementation Method 4
at least one parameter selected from the group consisting of an inlet flow pressure of the injection hole, the distance and an injection sequence is adjusted so that an interface between the drying gas and the liquid is stable
Data Source
AI summary
A method of flow control is provided. The method includes injecting a liquid onto a wafer via a dispense system. The dispense system includes a plate and an injection hole in the plate. The plate is positioned away from the wafer at a distance and has a diameter equal to or larger than the wafer. A drying gas is injected onto the wafer via the dispense system to push out the liquid. While injecting the drying gas onto the wafer via the dispense system, at least one parameter selected from the group consisting of an inlet flow pressure of the injection hole, the distance and an injection sequence is adjusted so that an interface between the drying gas and the liquid is stable.