Curved Mirror Optical System for Semiconductor Line Projection
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Solution Overview
Problem
Conventional optical systems for generating a straight line laser projection are prone to damage from semiconductor material sputtering and have limitations with point sources, require inefficient stepping movements for multiple parallel lines, and struggle with achieving desired line width and length, leading to increased production costs and reduced efficiency.
Innovation Solution
An apparatus using a curved mirror with a point source positioned on or near its axis of revolution, allowing for efficient irradiation of a straight line on a semiconductor substrate, minimizing optical element damage, and enabling simultaneous generation of multiple parallel lines with adjustable length and width, utilizing a point source such as an excimer laser for high-energy, high-speed processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cylindrical lenses are used to generate a straight line projection, then the line width can be controlled, but the lenses must be positioned very close to the semiconductor substrate, increasing the risk of damage from material sputtering
Solution Approach 1:
A curved mirror is introduced as an intermediary optical element between the laser source and the semiconductor substrate. The mirror reflects and shapes the laser beam into a straight line projection without requiring close proximity to the substrate, thus protecting the optical element from material sputtering while maintaining precise line width control through proper mirror curvature and positioning.
2Shape
If diffractive elements are used to generate a straight line projection, then the line shape can be formed, but the line width is difficult to control given the laser bandwidth and the lifetime of the elements decreases under high energy irradiation
Solution Approach 1:
The patent replaces diffractive optical elements with a curved mirror-based reflective system. This substitution eliminates the issues associated with diffractive elements under high energy laser irradiation, including difficulty in controlling line width due to laser bandwidth and reduced element lifetime. The curved mirror provides a more durable and controllable solution for generating straight line projections.
3Ease of operation
If a linear irradiation source is used to irradiate straight line shaped regions, then the irradiation can be performed, but the system is not compatible with point sources such as laser sources and requires inefficient stepping movements for multiple parallel lines
Solution Approach 1:
The patent uses a curved mirror to segment and redirect the point source laser beam into multiple parallel straight line projections simultaneously. This allows a single point source to irradiate multiple parallel lines without requiring stepping movements, thereby maintaining ease of operation with laser sources while dramatically improving production efficiency through simultaneous multi-line irradiation.
4Area of stationary object
If step-by-step irradiation is used to cover large area semiconductor substrates, then the entire area can be irradiated, but the irradiation speed is slow and production cost is high
Solution Approach 1:
The patent merges multiple straight line projections into a single optical system that can irradiate multiple parallel lines simultaneously. By combining the irradiation of multiple lines in one pass, the system covers large area semiconductor substrates much faster than step-by-step irradiation, thereby increasing irradiation speed and reducing production cost while maintaining comprehensive area coverage.
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 solution enhances production speed and cost efficiency by minimizing optical system risk, enabling high-speed, cost-effective irradiation of large-area semiconductor substrates with improved uniformity and flexibility in line length and width, suitable for applications like photovoltaics.
Implementation Method 1
a curved mirror (M) with a reflective surface of revolution, and b) a point source (S) generating an irradiation beam being incident on the curved mirror
Data Source
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AI summary
The present invention relates to an apparatus for irradiating a semiconductor comprising a curved mirror with a reflective surface of revolution, and a point source generating an irradiation beam being incident on the curved mirror along an incident direction, characterized in that the curved mirror and the point source form a system having an axis of revolution wherein the point source is provided on or near said axis of revolution, and that said axis of revolution substantially coincides with a straight line projection to be generated on a semiconductor substrate. Additionally, the present invention relates to the use of such apparatus for manufacturing a selective emitter grid, or for irradiating a large area semiconductor surface in a scanning movement.