Flexible Rigid Mold Segmentation for Nano-Imprint Precision
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Solution Overview
Problem
In nano-imprint lithography, molds with flexible materials deform along non-flat substrates, leading to pattern distortion and non-uniform transfer of diffraction gratings, affecting the characteristics and accuracy of semiconductor optical devices like DFB lasers.
Innovation Solution
A mold design featuring a flexible first base and rigid second bases spaced apart, allowing the flexible base to bend with substrate undulations while maintaining pattern integrity due to the rigidity of the second bases, ensuring accurate transfer of diffraction grating patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mold is made fully rigid to maintain pattern accuracy, then pattern shape is preserved, but the mold cannot deform along non-flat substrate surfaces
Solution Approach 1:
Different parts of the mold have different mechanical properties: the base is flexible to adapt to substrate contours, while the pattern portions and their supporting structures are rigid to maintain shape accuracy. This local differentiation of material properties resolves the contradiction between adaptability and precision.
Solution Approach 2:
The mold is segmented into flexible base regions and rigid pattern regions, allowing each region to perform its specialized function independently.
2Device complexity
If a single large pattern portion is used, then the mold structure is simple, but pattern distortion occurs due to flexibility
Solution Approach 1:
The mold pattern is divided into multiple smaller pattern portions spaced apart on the flexible base. This segmentation prevents the flexibility of the base from causing distortion of individual patterns, as each small pattern portion is independently supported and less susceptible to base deformation.
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 design prevents pattern distortion and maintains the accuracy of diffraction grating patterns on non-flat substrates, ensuring consistent reflection and emission wavelengths in semiconductor optical devices.
Implementation Method 1
The first base is made of a flexible material. When the pattern portion of the mold having such a structure is pressed against the resin layer, the flexible first base is bent along the surface of the resin layer.
Implementation Method 2
The second base is made of a rigid material. In addition, since the second bases have rigidity, the pattern portion of the mold can be prevented from being bent when the pattern portion is pressed against the resin layer.
Implementation Method 3
forming the pattern for the diffraction grating in the resin layer by curing the resin layer while pressing the pattern portion against the resin layer
Data Source
AI summary
A method fix forming a diffraction grating includes the steps of preparing a mold including pattern portions each having a pattern corresponding to a pattern for the diffraction grating; forming a first semiconductor layer on a substrate; forming a resin layer on the first semiconductor layer; pressing the pattern portions of the mold against the resin layer; forming the pattern for the diffraction grating in the resin layer by curing the resin layer; and forming the diffraction grating in the first semiconductor layer by etching the first semiconductor layer using the patterned resin layer. The mold includes a first base and a plurality of second bases disposed on the first base. The first base is made of a flexible material. Each second base is made of a rigid material. The second bases each include one pattern portion and are spaced apart from each other with a predetermined distance.