Resist Patterning with Local Heating for Faster UV Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Direct imaging systems for photoreactive resist patterning are limited by the available intensity of ultraviolet radiation, necessitating longer exposure times and reducing throughput, while thermal expansion can cause distortion and loss of accuracy in printed patterns.
Innovation Solution
A direct imaging system that combines ultraviolet radiation with transient, local thermal energy to heat a smaller area of the resist, reducing the required ultraviolet fluence and exposure time, and using a motion assembly to scan the heated area across the resist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ultraviolet radiation intensity is increased to reduce exposure time, then productivity improves, but thermal expansion causes distortion and loss of manufacturing precision
Solution Approach 1:
The patent divides the ultraviolet radiation into two distinct wavelength components: a first wavelength (e.g., 365 nm) that provides the primary polymerization effect with minimal thermal impact, and a second wavelength (e.g., 254 nm) that delivers the necessary thermal energy to accelerate the reaction. This segmentation allows independent optimization of each wavelength's contribution, enabling reduced total exposure time without excessive thermal accumulation that would cause substrate distortion and pattern inaccuracies.
Solution Approach 2:
The patent changes the spectral parameters of the ultraviolet radiation by introducing multiple wavelengths with different energy characteristics. The first wavelength operates at lower energy to minimize heating, while the second wavelength supplements with higher energy photons that both accelerate polymerization and provide controlled thermal effects. This parameter change enables the system to achieve faster curing speeds while maintaining pattern accuracy by balancing the dual roles of the different wavelength components.
2Productivity
If conventional single-wavelength ultraviolet radiation is used, then device complexity remains low, but exposure time increases reducing productivity
Solution Approach 1:
The patent merges two ultraviolet radiation sources operating at different wavelengths into a single integrated system that simultaneously irradiates the photoreactive resist layer. The combination of the first wavelength source (providing primary polymerization) and the second wavelength source (providing thermal acceleration) creates a synergistic effect that dramatically reduces exposure time and increases throughput, while the merged system maintains manageable complexity through coordinated control of the dual-wavelength delivery.
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
Increases throughput and maintains pattern accuracy by reducing the need for prolonged UV exposure and minimizing thermal distortion.
Implementation Method 1
A pattern of ultraviolet radiation is applied to polymerize the solder resist
Implementation Method 2
A thermal energy source is configured to heat a second area of the layer of the photoreactive material
Implementation Method 3
the thermal energy source includes a source of infrared radiation and projection optics configured to project the infrared radiation over the second area
Data Source
AI summary
A direct imaging system includes an ultraviolet radiation source, which is configured to irradiate a first area, having a first width, of a layer of a photoreactive material on a substrate with patterned ultraviolet radiation. A thermal energy source is configured to heat a second area of the layer of the photoreactive material while the ultraviolet radiation source irradiates the first area. The second area contains a part of the first area and having a second width less than the first width.