Distributed Bragg Reflector for Semiconductor Radiation Protection
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Solution Overview
Problem
Plasma treatment processes in semiconductor device fabrication, such as plasma etching, produce ultraviolet radiation that can cause defects, impurities, and broken chemical bonds in CMOS devices, and conventional methods to mitigate these issues, like using radiation-absorbing materials, are costly and limit the use of certain photolithographic processes.
Innovation Solution
Forming a reflective structure with two dielectric materials of different refractive indices over radiation-sensitive structures to selectively reflect ultraviolet radiation within a predetermined wavelength range, thereby protecting the structures from damage while allowing beneficial radiation to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If radiation-absorbing material is used to protect radiation-sensitive structures, then reliability is improved, but device complexity and material cost increase
Solution Approach 1:
The patent converts the harmful ultraviolet radiation produced during plasma processing into a beneficial effect by using it to selectively remove the radiation-absorbing material (anti-reflective coating) from exposed areas. The radiation that previously caused damage is now utilized as a tool for precise material removal, protecting the underlying radiation-sensitive structures while enabling pattern transfer.
Solution Approach 2:
The radiation-absorbing material serves as an intermediary layer between the plasma processing equipment and the radiation-sensitive structures. It absorbs the harmful ultraviolet radiation during plasma treatment, preventing the radiation from reaching and damaging the CMOS devices underneath, thus mediating the interaction between the processing equipment and the sensitive structures.
2Reliability
If thicker radiation-absorbing material is used to impede radiation transmittance, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the thickness parameter of the radiation-absorbing material to an optimized range that provides sufficient radiation protection while minimizing material usage and cost. Rather than using excessively thick layers, the material thickness is precisely controlled to balance radiation absorption effectiveness with manufacturing economy.
Solution Approach 2:
The harmful ultraviolet radiation is converted into a useful tool for selectively removing the radiation-absorbing material after it has served its protective function. This eliminates the need for additional removal steps and reduces overall manufacturing complexity.
3Reliability
If radiation-absorbing material is applied, then reliability is improved, but photolithographic process versatility deteriorates
Solution Approach 1:
The patent employs periodic action by using alternating cycles of plasma processing and photolithography. During plasma processing cycles, the radiation-absorbing material protects the structures; during photolithography cycles, the material is selectively removed or modified. This periodic switching enables both protection and pattern formation to occur sequentially.
Solution Approach 2:
The radiation-absorbing material's properties are made dynamic rather than static. Its thickness and composition are adjusted at different stages of the manufacturing process to meet different requirements: providing radiation protection during plasma treatment, then allowing selective removal during photolithography. This dynamic adaptability enables versatility in photolithographic 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 enhances the reliability, performance, and durability of semiconductor devices by reducing radiation-based damage and defects, while enabling the use of longer wavelengths in photolithographic processes and reducing material costs.
Implementation Method 1
forming a reflective structure with two dielectric materials of different refractive indices over radiation-sensitive structures to selectively reflect ultraviolet radiation within a predetermined wavelength range
Implementation Method 2
reflective structure with two dielectric materials of different refractive indices
Data Source
AI summary
A method of forming a semiconductor device structure comprises forming at least one reflective structure comprising at least two dielectric materials having different refractive indices over at least one radiation-sensitive structure, the at least one reflective structure configured to substantially reflect therefrom radiation within a predetermined wavelength range and to substantially transmit therethrough radiation within a different predetermined wavelength range. Additional methods of forming a semiconductor device structure are described. Semiconductor device structures are also described.