Semiconductor Etching Apparatus Silica Concentration Control
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Solution Overview
Problem
In semiconductor manufacturing, the frequent replacement of etching solutions like phosphoric acid aqueous solutions is undesirable due to silica precipitation, and existing technologies fail to efficiently manage silica concentration during the etching process without wasteful solution usage.
Innovation Solution
A semiconductor manufacturing apparatus with a liquid supplier, recovery and drainage channels, and switching modules controlled by a processor to adjust the etching solution's concentration by alternating recovery and drainage, ensuring efficient use and preventing silica precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the phosphoric acid aqueous solution is circulated to treat the silicon nitride film, then the silica dissolves from the film, but the silica precipitates in the solution over time
Solution Approach 1:
The patent applies dynamics by making the liquid circulation path configurable between closed-loop and open-loop modes. The switching module dynamically changes the circulation configuration based on process needs, allowing the system to adapt between maintaining solution concentration (closed-loop) and preventing precipitation (open-loop with drainage), thus resolving the contradiction between continuous silica dissolution and precipitation prevention
Solution Approach 2:
The patent changes the parameter of liquid circulation configuration between closed-loop and open-loop modes. By switching between these parameter states, the system can control whether the phosphoric acid solution maintains constant volume (closed-loop) or allows concentration control through drainage (open-loop), thereby managing the silica concentration to prevent precipitation while maintaining dissolution capability
2Object-affected harmful factors
If the phosphoric acid aqueous solution is frequently replaced to prevent silica precipitation, then the precipitation is prevented, but the solution is wasted
Solution Approach 1:
The patent implements discarding and recovering by selectively draining only the portion of liquid that contains precipitated silica (open-loop drainage) while maintaining the ability to recover and reuse the bulk solution through closed-loop circulation. This partial discarding approach prevents precipitation without complete solution replacement, reducing waste while maintaining effectiveness
Solution Approach 2:
The dynamic switching between closed-loop and open-loop circulation modes allows the system to adapt to different process stages. During early stages with low silica concentration, closed-loop mode maximizes solution reuse. As silica accumulates, the system switches to open-loop mode to drain precipitated silica, thereby preventing precipitation without frequent complete replacements
3Loss of substance
If the liquid circulation is maintained in a closed-loop configuration, then the solution is reused efficiently, but the silica concentration increases causing precipitation
Solution Approach 1:
The system dynamically switches between closed-loop and open-loop circulation configurations based on silica concentration levels. The switching module monitors the process state and transitions from closed-loop (high reuse efficiency) to open-loop (precipitation control) when needed, resolving the contradiction between solution reuse and precipitation prevention
Solution Approach 2:
The patent employs feedback control where the system monitors silica concentration in the phosphoric acid solution and adjusts the circulation configuration accordingly. When silica concentration reaches a threshold, the feedback mechanism triggers a switch from closed-loop to open-loop mode to drain the solution, preventing precipitation while minimizing waste
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
The apparatus effectively maintains silica concentration within a predetermined range, preventing precipitation and optimizing etching solution usage by dynamically adjusting recovery, drainage, and supplementation based on the liquid contacting area, thereby reducing wastage and maintaining process efficiency.
Implementation Method 1
silica dissolves from the silicon nitride film in the phosphoric acid aqueous solution
Data Source
AI summary
In one embodiment, a semiconductor manufacturing apparatus includes a liquid supplier configured to supply liquid to a film on a substrate and cause a substance to dissolve from the film in the liquid. The apparatus further includes a first channel configured to recover the liquid supplied to the film and feed the liquid again to the liquid supplier, and a second channel configured to drain the liquid supplied to the film. The apparatus further includes a first switching module configured to switch a discharge destination of the liquid supplied to the film between the first and second channels, and a second switching module configured to switch between supplementing and not supplementing the first channel with new liquid. The apparatus further includes a controller configured to control the first and second switching modules to adjust concentration of the substance in the liquid to be supplied to the film.