Laser Irradiation Apparatus with Changeable Slit for Homogeneous Annealing
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Solution Overview
Problem
Conventional laser irradiation apparatuses face challenges in achieving homogeneous energy distribution during laser annealing of semiconductor films, leading to inhomogeneous annealing and requiring complex optical systems and time-consuming alignment adjustments for beam size changes, resulting in low throughput and increased costs.
Innovation Solution
A laser irradiation apparatus with a diffractive optical element and a slit with a changeable slit opening allows for the formation of laser beams with homogeneous energy distribution, enabling easy adjustment of beam size and direction without the need for optical realignment, using a slit to block inhomogeneous end portions and project beams of varying lengths onto the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser irradiation apparatus uses multiple cylindrical lens arrays to shape the laser beam into a linear spot, then the energy distribution on the irradiation surface becomes homogeneous, but the apparatus size and cost increase
Solution Approach 1:
The patent combines multiple optical functions (beam shaping, homogenization, and size adjustment) into a single diffractive optical element. This element integrates the capabilities of what would traditionally require multiple cylindrical lens arrays, thereby reducing the number of components while maintaining homogeneous energy distribution across the irradiation surface
Solution Approach 2:
The diffractive optical element is designed to perform multiple functions simultaneously: it shapes the laser beam into a linear spot, homogenizes the energy distribution, and allows for adjustable beam size through a simple slit mechanism. This multi-functional design eliminates the need for separate optical components for each function, reducing overall device complexity
2Adaptability or versatility
If the laser beam size is changed in conventional apparatuses, then the beam can be adapted to different processing requirements, but optical realignment is required which consumes time
Solution Approach 1:
The patent implements a dynamic beam size adjustment mechanism using a slit whose opening width can be changed without moving or replacing optical components. The slit width is adjustable along the minor axis of the linear beam, allowing real-time adaptation to different processing requirements while maintaining fixed optical alignment
Solution Approach 2:
The diffractive optical element is pre-configured with a slit structure that allows beam size adjustment through simple width changes rather than requiring subsequent realignment operations. This preliminary design eliminates the need for time-consuming optical realignment when beam size needs to be modified
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 the homogeneity of crystallinity and reduces the variation in electric characteristics, improving the reliability and throughput of semiconductor device manufacturing, particularly for active matrix liquid crystal display devices, by allowing for quick adaptation to different substrate sizes and designs.
Implementation Method 1
a diffractive optical element (102), a slit (103) and a condensing lens (105)... A laser beam emitted from a laser oscillator (101) is shaped into a linear spot with homogeneous energy distribution by the diffractive optical element (102)
Implementation Method 2
a diffractive optical element (102), a slit (103) and a condensing lens (105)... the laser beam formed at the slit (103) is projected to an irradiation surface (107) so that the laser beam with homogeneous energy distribution is formed on the irradiation surface (107)
Implementation Method 3
laser annealing has advantages that processing time can be drastically shortened and a semiconductor film over a substrate is heated selectively and locally... laser irradiation apparatus for carrying out annealing to, for example, a semiconductor material homogeneously and effectively
Data Source
AI summary
The present invention is to provide a laser irradiation apparatus for forming a laser beam which has a shape required for the annealing and which has homogeneous energy distribution, by providing a slit at an image-formation position of a diffractive optical element, wherein the slit has a slit opening whose length is changeable.The laser irradiation apparatus comprises a laser oscillator, a diffractive optical element, and a slit, wherein the slit has a slit opening whose length in a major-axis direction thereof is changeable, wherein a laser beam is delivered obliquely to a substrate, and wherein the laser beam is a continuous wave solid-state, gas, or metal laser, or a pulsed laser with a repetition frequency of 10 MHz or more.