Local Exposure Apparatus for FPD Resist Uniformity
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Solution Overview
Problem
The photolithography process for forming circuit patterns in FPDs faces issues with uneven resist film thickness, leading to irregular line widths and pitches in the resultant patterns due to half exposure processing using resist patterns with thick and thin portions.
Innovation Solution
A local exposure apparatus and method that enhances in-plane thickness uniformity of the residual resist film by selectively controlling a linear array of light-emitting elements to emit lights during exposure, ensuring precise illumination and development of specific areas on a substrate, thereby reducing line width and pitch irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If half exposure processing is used to create resist patterns with thick and thin portions, then the number of photomasks and processing steps is reduced, but the in-plane thickness uniformity of the residual resist film deteriorates
Solution Approach 1:
The patent applies local quality by using a linear array of independently controllable light-emitting elements to provide spatially varying exposure doses to different regions of the substrate. Each light-emitting element can be controlled to emit light with different intensity and duration, creating localized thickness adjustments in the resist film while maintaining overall processing efficiency.
2Productivity
If half exposure processing is used to create resist patterns with thick and thin portions, then the number of photomasks is reduced, but the line width and pitch uniformity of the resultant patterns deteriorates
Solution Approach 1:
The patent uses local quality by enabling different regions of the substrate to receive customized exposure doses through the linear array of light-emitting elements. This allows precise control over the thickness of the residual resist film in different areas, which directly determines the line width and pitch of the resulting patterns, thereby maintaining pattern uniformity while reducing the number of photomasks.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the exposure dose parameters (intensity and duration) for each light-emitting element in the linear array. By varying these parameters across different spatial positions, the system achieves uniform line width and pitch control without requiring multiple photomasks with different patterns.
3Manufacturing precision
If a linear array of light-emitting elements is used for selective illumination, then the in-plane thickness uniformity of the residual resist film is enhanced, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the illumination system into a linear array of discrete, independently controllable light-emitting elements. This segmentation allows precise local control over exposure doses while maintaining a relatively simple overall device structure that can be integrated into existing photolithography systems.
4Manufacturing precision
If selective light emission control is implemented during exposure, then line width and pitch irregularities are reduced, but the control system complexity increases
Solution Approach 1:
The patent applies parameter changes by controlling the intensity and duration of light emission from each element in the linear array. This allows dynamic adjustment of exposure parameters to compensate for variations in resist thickness and achieve uniform line width and pitch, while the control system complexity is managed through efficient software algorithms.
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 solution achieves uniform resist film thickness and reduces line width and pitch irregularities, enabling more precise and consistent circuit pattern formation by controlling the exposure and development process with advanced light emission control.
Implementation Method 1
a light source including a plurality of light-emitting elements linearly arranged in a direction intersecting a substrate conveying direction above the substrate conveying path within the chamber, the light source being capable of illuminating the photosensitive film on the substrate conveyed below the light source with lights emitted from the plurality of light-emitting elements
Implementation Method 2
In the manufacture of, e.g., an FPD (Flat Panel Display), a circuit pattern is formed through a so-called photolithography process
Data Source
AI summary
A local exposure apparatus for performing exposure processing on a specific area of a photosensitive film formed on a substrate includes a substrate conveyor configured to define a substrate conveying path and to horizontally convey the substrate along the substrate conveying path, a chamber configured to define an exposure processing space, a light source including a plurality of light-emitting elements linearly arranged above the substrate conveying path, a light emission drive unit configured to selectively drive one or more of the light-emitting elements of the light source, a substrate detector configured to detect the substrate conveyed by the substrate conveyor, and a control unit configured to control the light emission drive unit such that, when the specific area of the photosensitive film moves below the light source, only the light-emitting elements capable of irradiating the given area are driven to emit the light.