In-situ Plasma Side Wall Resistance Monitoring
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Solution Overview
Problem
Conventional plasma monitoring methods cannot measure in-situ the resistance of a contact hole side wall or the electric current flowing through it during plasma processing, leading to inaccuracies in simulating plasma processes and potential electron blocking effects, which can result in shape abnormalities and etching stop issues in semiconductor production.
Innovation Solution
A plasma monitoring method using sensors with electrodes and resistance elements placed within the plasma chamber to measure the resistance and current of the side wall in real-time, allowing for accurate in-situ data collection during plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe is brought into contact with the sample in the atmosphere to measure side wall resistance, then the resistance can be measured, but the measurement accuracy deteriorates due to difference in environmental conditions between plasma chamber and atmosphere
Solution Approach 1:
The patent introduces a sensor as an intermediary device that can be placed inside the plasma chamber to measure side wall resistance in-situ. The sensor includes electrodes and measurement circuits that enable resistance measurement without requiring sample extraction to atmosphere, thus eliminating the measurement accuracy deterioration caused by environmental differences between plasma chamber and atmosphere.
2Reliability
If plasma process conditions are optimized to form low-resistance deposition film on side wall, then electron blocking effect is relaxed, but the complexity of process control increases due to need for real-time monitoring
Solution Approach 1:
The patent implements a feedback mechanism by measuring side wall resistance in real-time during plasma processing and using this information to adjust plasma process conditions. The sensor provides continuous feedback on deposition film resistance, enabling dynamic optimization of etching parameters to maintain low-resistance side walls and relax electron blocking effects.
Solution Approach 2:
The patent replaces complex mechanical sampling and post-processing measurement systems with an in-situ electrical measurement system. Instead of extracting samples and using probes in atmosphere, the system uses electrical measurements through electrodes embedded in the plasma chamber to directly monitor side wall resistance, simplifying the overall monitoring architecture.
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
Enables precise measurement of side wall resistance and current, improving the accuracy of plasma process simulations and preventing electron blocking effects, thus ensuring consistent and reliable semiconductor manufacturing.
Implementation Method 1
measuring in-situ a resistance of a side wall of the pattern and/or an electric current flowing in the side wall of the pattern
Implementation Method 2
a voltage is applied between the top and bottom of the contact hole, and the side wall resistance is measured
Implementation Method 3
Electrons (negative electric charge) and positive ions fall on a wafer surface from plasma when plasma treatment is conducted on the wafer placed on a stage inside a plasma chamber
Implementation Method 4
The difficulty of the electrons reaching the contact hole bottom due to the incident angle of the electrons is called the electron blocking (or electron shielding) effect
Implementation Method 5
The deposition film is an etching reaction product that is provided on the side wall of the contact hole as a result of chemical reaction between the film to be etched and radicals emitted from plasma during contact etching
Implementation Method 6
radicals emitted from plasma during contact etching
Data Source
AI summary
A plasma monitoring method measures in-situ a resistance of and a current flowing in a side wall. A monitoring system has two sensors in a plasma chamber, each having upper and lower electrodes. An external resistance element is connected only to one of the two sensors, in parallel to the wires extending from the upper and lower electrodes of the sensor concerned. Consequently, a resistance between the upper and lower electrodes is different in the two sensors, and two different values of potential difference between the upper and lower electrodes are obtained in-situ. Because a resistance value of the external resistance element is known, a resistance value of a side wall of a contact hole per one contact hole is obtained in-situ, and consequently an electric current flowing in the side wall of the contact hole per one contact hole can be obtained.