Multispectral Fabry-Pérot Filter Transfer Process for Surface Quality
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Solution Overview
Problem
Current methods for producing multispectral filters require numerous successive lithography and etching steps, leading to technological constraints such as profile deformations and degraded surface qualities, which are challenging to maintain the aspect ratio and form factor necessary for devices like multispectral filters.
Innovation Solution
A method involving the deposition of a resin layer on a substrate, followed by three-dimensional structuring using lithography, and subsequent transfer to a carrier substrate with photoelectric transducers, allowing for the elimination of successive lithography and etching steps, and enabling the creation of Fabry-Pérot cavities with improved surface quality and form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional lithography and etching steps are used to produce different thicknesses of dielectric layers, then multiple color filters can be formed, but profile deformations and degraded surface qualities occur
Solution Approach 1:
The patent applies preliminary action by first forming a planarized dielectric layer before transferring the handle substrate to the carrier substrate. This ensures that the dielectric layer is already planarized and ready for the subsequent bonding step, avoiding the need for repeated etching steps that cause profile deformations and surface quality degradation.
Solution Approach 2:
The patent uses an intermediary approach by introducing a handle substrate as a temporary carrier for forming the Fabry-Pérot cavities. The handle substrate allows the dielectric layer to be formed and planarized in a controlled environment before final transfer to the carrier substrate, thereby maintaining surface quality and profile accuracy throughout the manufacturing process.
2Manufacturing precision
If numerous successive lithography and etching steps are performed, then different thicknesses of dielectric layers can be achieved, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent performs the dielectric layer formation and planarization steps in advance on the handle substrate before final transfer. This preliminary action allows all necessary thickness variations to be established in a single planarization step rather than through multiple sequential etching steps, significantly reducing manufacturing complexity.
Solution Approach 2:
The patent merges multiple separate lithography and etching steps into a single integrated process. By forming all dielectric patterns and achieving all required thickness variations through one planarization operation on the handle substrate, the patent combines what would otherwise be multiple discrete manufacturing steps into one unified process.
3Adaptability or versatility
If conventional etching approaches are used to transfer patterns vertically into dielectric material, then color filters can be formed, but surface quality and form factor are degraded
Solution Approach 1:
The patent inverts the conventional approach by forming the dielectric patterns with their final thickness variations on the handle substrate through planarization, then transferring the entire structure to the carrier substrate. This reversal eliminates the need for vertical etching into the dielectric material on the final device, thereby preserving surface quality and aspect ratio.
Solution Approach 2:
The handle substrate serves as an intermediary platform that enables pattern formation without compromising the final device's surface quality. By performing all pattern transfer operations on this temporary substrate and then moving the completed structure to the carrier substrate, the patent protects the final device from the harmful effects of aggressive etching processes.
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 approach simplifies the production process, reduces the number of steps required, and maintains the desired form factor and surface quality of multispectral filters, enhancing their performance and efficiency.
Implementation Method 1
Three-dimensional structuring of the layer of resin by lithography so as to obtain at least two resin patterns of different heights
Implementation Method 2
a Fabry-Pérot cavity formed between a first reflective layer and a second reflective layer
Implementation Method 3
one or more dielectric (or possibly semiconductor) cavities formed between two thin metal films having a metal mirror function so as to form a Fabry-Pérot cavity
Implementation Method 4
each pattern facing a photoelectric transducer
Data Source
Figure 1
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AI summary
The invention relates to a method for manufacturing a multispectral filter for electromagnetic radiation comprising at least two color filters, each filter comprising a first reflective layer, a second reflective layer, a layer of Fabry-Pérot cavity dielectric material, the thickness of the dielectric layer of the two color filters being different and each of the two filters being opposite a photoelectric transducer.The process comprises the following steps: - Deposition of a resin layer onto a substrate, called the handle substrate; - Three-dimensional structuring of the resin layer by lithography to obtain at least two resin patterns of different heights, at least one of the patterns having a maximum reference height; - Deposition of a layer made of the dielectric material intended to form the dielectric patterns of the Fabry-Pérot cavities and planarization by removal of the dielectric material with selective stopping at the top of the tallest resin pattern; - Transfer of the planarized face of the handle substrate onto the upper face of a carrier substrate; - Removal of the handle substrate and the resin to expose at least two dielectric patterns of Fabry-Pérot cavities of different thicknesses on the surface and deposition of a reflective layer on the at least two dielectric patterns of Fabry-Pérot cavities, forming the second reflective layer.