Movable Endpoint Detection Optics for Anti-Deposition Ion Beam Etching
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Solution Overview
Problem
Existing ion beam etching systems face poor real-time monitoring performance due to stationary OES endpoint detection devices being far from the wafer surface, leading to weak emission line reception and frequent maintenance needs.
Innovation Solution
An endpoint detection device with a light-transmitting piece positioned away from the etching environment and an anti-deposition member forming a light-guiding channel, combined with a detection element mounted on a lower electrode swing arm, allowing closer proximity to the wafer for enhanced spectral reception and reduced deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the OES endpoint detection device is fixed on the chamber and stationary (on the top, transfer side, or ion source side), then the device structure is simple and easy to install, but the distance from the wafer surface is relatively long resulting in weak emission line reception intensity and poor real-time monitoring performance
Solution Approach 1:
The patent applies the dynamics principle by making the detection device movable rather than stationary. The detection device is mounted on a movable platform that can adjust its position relative to the wafer surface, allowing it to dynamically optimize the detection distance. This enables the device to maintain high measurement precision by being close to the wafer while still having a manageable structural complexity through the use of standard movable mounting mechanisms.
2Measurement precision
If the light-transmitting piece is positioned close to the etching environment for better detection, then the emission line reception intensity is improved, but the anti-deposition capability deteriorates requiring frequent maintenance and reducing mean time between cleans (MTBC)
Solution Approach 1:
The patent applies segmentation by dividing the detection system into two separate components: a light-transmitting piece that remains in the etching environment for optimal spectral detection, and a detection element that is positioned away from the etching environment. This segmentation allows each component to perform its function optimally - the light-transmitting piece captures strong emission lines close to the wafer, while the detection element operates in a cleaner environment, reducing deposition and extending maintenance intervals.
3Duration of action of stationary object
If the light-transmitting piece is positioned away from the etching environment, then the anti-deposition capability is improved extending maintenance interval, but the emission line reception intensity decreases resulting in poor real-time monitoring performance
Solution Approach 1:
The patent uses the light-transmitting piece as an intermediary component that bridges the gap between the etching environment and the detection element. The light-transmitting piece is positioned close to the wafer to capture strong emission lines, while the detection element remains away from the etching environment. The light-transmitting piece transmits the optical signals from the etching zone to the detection element, enabling high-quality real-time monitoring while maintaining a long maintenance interval for the detection element.
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 device extends the maintenance interval of the light-transmitting piece and enhances monitoring performance by preventing deposition, ensuring robust and precise endpoint detection.
Implementation Method 1
a light-transmitting piece (40)... The mounting bottom plate (20) forms a light-transmitting hole (21) leading to the light-transmitting piece (40)
Implementation Method 2
OES endpoint detection devices... The principle is that at the etching endpoint, the intensity of light emitted by specific product groups drops sharply
Implementation Method 3
The ion beam, possessing certain energy, enters the reaction chamber and bombards a surface of the wafer on the stage, causing material atoms to sputter, thereby achieving the etching purpose
Implementation Method 4
During ion beam etching, inert gases such as Ar, Kr, or Xe are filled into an ion source discharge chamber and ionized to form uniform plasma
Data Source
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AI summary
An endpoint detection apparatus and an ion beam etching system. The endpoint detection apparatus comprises a mounting bottom plate, an anti-deposition member, a light-transmitting piece, and a detection element. The light-transmitting piece is mounted on the outer side of the mounting bottom plate by means of a fixing member, and the mounting bottom plate is provided with a light-transmitting hole leading to the light-transmitting piece. The anti-deposition member is arranged on the inner side of the mounting bottom plate and extends from the mounting bottom plate in the direction away from the inner side surface of the mounting bottom plate, a light guide channel corresponding to the light-transmitting hole being provided in the anti-deposition member. The detection element is connected to the mounting bottom plate, is located on the outer side of the light-transmitting piece, and corresponds to the light-transmitting piece. The endpoint detection apparatus has an anti-deposition effect, and can effectively prevent particles from being deposited on the light-transmitting piece, thus greatly prolonging the maintenance interval of the light-transmitting piece while not affecting the normal detection function.