Curved Photolithography Patterns Using Defocused Light Diffusion
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Solution Overview
Problem
Conventional photolithography processes for manufacturing microstructures in photosensitive resin layers are complex and inflexible in terms of geometry, particularly for creating curved wall patterns, which are essential for improving the performance of optoelectronic devices like diodes.
Innovation Solution
A method involving defocused lithography is used to create a multilayer assembly with a photosensitive resin containing diffusing particles, allowing light radiation to be laterally diffused, forming curved sidewalls by positioning the mask and multilayer assembly out of focus, and then removing exposed or unexposed regions to form patterns or cavities with curved walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional focused photolithography is used to manufacture microstructures, then high resolution patterns can be obtained, but the process is complex and inflexible for creating curved wall patterns
Solution Approach 1:
The patent changes the focusing parameter of the lithography system from focused to defocused, and modifies the photosensitive resin composition by adding diffusing particles. This parameter change enables curved wall patterns to be formed in a single exposure step, simplifying the manufacturing process while maintaining pattern precision
Solution Approach 2:
The patent uses a composite photosensitive resin containing diffusing particles (such as TiO2, SiO2, or ZrO2) dispersed in the resin matrix. This composite material enables light diffusion within the resin layer, creating curved exposure profiles that form curved wall patterns without requiring complex multi-step processes
2Shape
If conventional photolithography with focused radiation is used, then straight wall patterns are obtained, but curved wall patterns require successive exposures which are complex to implement
Solution Approach 1:
By changing from focused to defocused lithography and incorporating diffusing particles in the photosensitive resin, the patent enables curved wall geometries to be achieved in a single exposure step, greatly improving manufacturing ease and process flexibility
Solution Approach 2:
The diffusing particles act as intermediaries that scatter and diffuse the incident light radiation within the photosensitive resin layer. This mediation creates a gradual light intensity distribution that forms curved exposure profiles, enabling curved wall patterns without complex successive exposures
3Shape
If diffusing particles are added to the photosensitive resin, then curved sidewall patterns can be formed, but the resin composition becomes more complex
Solution Approach 1:
The patent modifies the resin composition by adding diffusing particles with specific properties (size, material type, concentration) to control the curvature of sidewalls. While this increases composition complexity, it enables precise control over wall geometry through parameter optimization
Solution Approach 2:
The diffusing particles are distributed throughout the photosensitive resin to create localized light diffusion effects. This local modification of light interaction enables curved sidewall formation specifically at the pattern boundaries while maintaining overall process simplicity
4Reliability
If defocused lithography with diffusing particles is used, then curved wall patterns are obtained with improved light extraction, but the manufacturing process differs from conventional methods
Solution Approach 1:
The patent adopts defocused lithography parameters and modified resin composition to create curved wall patterns that improve light extraction efficiency for optoelectronic devices. This parameter change enhances device performance while establishing a new standardized process
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 method simplifies the creation of curved sidewall patterns, enhancing the performance of optoelectronic devices by improving light extraction and wavelength conversion efficiency, while reducing optical crosstalk and enhancing contrast between neighboring diodes.
Implementation Method 1
the incident light radiation is laterally diffused by the particles as the incident light radiation penetrates the photosensitive layer
Implementation Method 2
Photolithography is a technique commonly used for the production of microstructures in photosensitive resin layers, using a mask having opaque regions, typically made of chrome, to light radiation
Implementation Method 3
TiOz is a wide band gap semiconductor transparent to wavelengths in the visible range, and which absorbs ultraviolet (UV) radiation
Data Source
Figure 1A~2
Figure 3
Figure 4A
AI summary
The invention relates to a method for forming, by defocused lithography, a stack (1) comprising a photosensitive layer (10) based on a photosensitive resin comprising so-called "diffusing" particles, said stack (1) further comprising at least one pattern (20, 20') delimited at least in part by a curved side wall such that an intersection of the curved wall with a plane substantially perpendicular to the main extension plane of the stack (1) forms a curved line. The invention also relates to the production of an optoelectronic device (100) comprising the stack (1), in which the at least one pattern (20, 20') is at least one cavity delimited at least in part by said curved side wall, and at least one light-emitting diode (50) arranged in the at least one cavity (20).