Spectral Feature Control for Lithography Light Beams
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Solution Overview
Problem
In semiconductor lithography, maintaining accurate spectral features of light beams, such as bandwidth, is crucial for controlling critical dimensions, but existing technologies struggle to stabilize these features when the pulse repetition rate of light beams is modified, leading to unacceptable variations in critical dimensions and unreliable performance.
Innovation Solution
A method and system that control the spectral features of pulsed light beams by determining adjustments to the pulse repetition rate and compensating for variations through a correlation recipe, using a spectral feature selection apparatus with adjustable optical components, such as prisms, to maintain spectral features within a predetermined stable range during exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pulse repetition rate of the light beam is modified to improve productivity, then the exposure speed increases, but the spectral features (bandwidth) vary leading to unacceptable critical dimension control
Solution Approach 1:
The system continuously monitors the actual pulse repetition rate and uses feedback control to adjust the spectral features in real-time. A controller receives signals about the pulse repetition rate and automatically modifies optical components (such as gratings or prisms) to compensate for spectral drift, ensuring critical dimension stability even when exposure speed changes.
Solution Approach 2:
The system dynamically changes optical parameters (spectral features, bandwidth, wavelength) in response to changes in pulse repetition rate. By adjusting these parameters through controllable optical components, the system maintains optimal critical dimension control across different productivity levels.
2Adaptability or versatility
If the pulse repetition rate is changed to adapt to different exposure requirements, then the system becomes more versatile, but the spectral features become unstable
Solution Approach 1:
The system transitions from static spectral configuration to dynamic spectral control. Optical components such as tunable gratings, prisms, or filters are made adjustable in real-time, allowing the spectral features to adapt dynamically to different pulse repetition rates while maintaining stability through active control mechanisms.
Solution Approach 2:
The control system continuously monitors both the pulse repetition rate and spectral features, using feedback loops to automatically adjust optical components and maintain spectral stability across varying operational conditions and adaptability requirements.
3Device complexity
If existing technologies are used without compensation mechanisms, then the system is simpler, but unacceptable variations in critical dimensions occur when pulse repetition rate is modified
Solution Approach 1:
The system introduces controllable optical components (gratings, prisms, filters) as intermediaries between the light source and the substrate. These intermediaries actively compensate for spectral variations caused by pulse repetition rate changes, maintaining critical dimension consistency through their adjustable optical properties.
Solution Approach 2:
A control system with feedback mechanisms monitors spectral features and pulse repetition rate, automatically adjusting the intermediary optical components to compensate for variations and maintain manufacturing precision across different operating conditions.
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 that the spectral features of pulsed light beams are maintained within a stable range, thereby maintaining the critical dimensions of microelectronic features on semiconductor substrates to within an acceptable range, even when the pulse repetition rate is modified, enhancing the reliability of the lithography process.
Implementation Method 1
rotating a prism of the spectral feature selection apparatus. The prism of the spectral feature selection apparatus can be rotated to thereby change the spectral feature
Data Source
AI summary
A spectral feature of a pulsed light beam produced by an optical source is controlled by a method. The method includes producing a pulsed light beam at a pulse repetition rate; directing the pulsed light beam toward a substrate received in a lithography exposure apparatus to expose the substrate to the pulsed light beam; modifying a pulse repetition rate of the pulsed light beam as it is exposing the substrate. The method includes determining an amount of adjustment to a spectral feature of the pulsed light beam, the adjustment amount compensating for a variation in the spectral feature of the pulsed light beam that correlates to the modification of the pulse repetition rate of the pulsed light beam. The method includes changing the spectral feature of the pulsed light beam by the determined adjustment amount as the substrate is exposed to thereby compensate for the variation in the spectral feature.