Manufacturing-aware metalens design may reduce transition time from design to production

Design with Manufacturing Awareness is a design philosophy that emphasizes the understanding and consideration of the manufacturing process during product design and development. The purpose of this design approach is to reduce the conversion time from the design stage to the production stage, reduce production costs, improve product quality, and shorten the time to market.

As augmented reality (AR) and virtual reality (VR) technologies develop, the demand for photonic devices is increasing, and the need for efficient and miniaturized components has become more urgent. Two devices that are currently attracting much attention in the industry include meta-lenses and optical components, both of which are critical in various applications such as automotive lidar, cameras, and AR/VR systems. However, it is challenging to support the large-scale production of these devices and ensure their performance. Therefore, incorporating manufacturing awareness into the design will help improve product design performance and reduce the design-manufacturing-testing cycle, thereby saving time and cost.

Meta-lens design with “manufacturing awareness”

Metaoptics are planar optical components that are entering the high-volume manufacturing (HVM) phase using conventional integrated circuit manufacturing techniques. Metaoptics are built on a metasurface composed of subwavelength units that are fabricated in a high-refractive-index film with a thickness of about 0.5 to 3+ microns. The metasurface can be used as a focusing lens, beam splitter, waveguide, or other optical functions.

As a revolutionary innovation in the optical industry, metalenses are expected to replace traditional curved lenses and become a key technology for the next generation of compact imaging, sensing and display applications due to their ultra-thin characteristics and ability to elastically modulate light fields. However, in the process of realizing large-scale design and manufacturing of metalenses, there are many challenges such as mask manufacturing, corner rounding, etching, corner filleting, layout generation, and substrate flatness. In addition, the lithography and etching processes are often difficult to achieve ideal square corners and vertical sidewalls in actual operations. These manufacturing defects will have an adverse effect on the performance indicators of the metasurface structure.

Incorporating "manufacturing awareness" into the design phase of the meta-lens helps designers better understand and overcome various challenges that may arise during the manufacturing process. This approach integrates the advanced technologies of Synopsys' optical design (RSoft Photonic Device Tools) and manufacturing process design (Synopsys Proteus, S-Litho, and Sentaurus Process Explorer) software to ensure that the manufactured meta-lens is closer to the optimal performance under a specific manufacturing process. It helps to achieve rule transfer between optical design and manufacturing design, shorten the design cycle, and is committed to "first-time correct" meta-lens design.

▲ Figure 1 Integrating "manufacturing awareness" into the design stage of the super-lens. First, the manufacturing process of the super-atom is simulated to form a super-atom library with "manufacturing awareness", and then the super-atom library is used to manufacture a super-lens with better performance.

Solving similar challenges in AR/VR devices

Manufacturing challenges are not limited to meta-lenses. For optical waveguide components currently used on a large scale in the AR/VR industry, how to achieve low-cost manufacturing of high-precision surface relief gratings is a crucial step and has become one of our research and focus.

Surface relief gratings (SRGs) have micrometer-scale features that are very sensitive to small variations in surface chamfers, etching, and roughness produced during the manufacturing process. For optical components, precise control of the spatial diffraction efficiency of SRGs becomes one of the key parameters because it can directly affect the performance of the entire optical system.

Any deviation in the SRG shape will affect the diffraction efficiency. Ignoring these changes in the early stages of optimization may lead to multiple design iterations, which will affect the efficiency of achieving the target performance, that is, the light uniformity problem in the eye box. For optical components, considering the impact of SRG manufacturing defects on performance at an early stage and incorporating "manufacturing awareness" into the optimization process will help improve the final performance and design robustness, and take corresponding measures in the design stage to reduce potential risks.

As shown in Figure 2, Synopsys provides a complete design flow that allows designers to integrate the manufactured SRG profile at an early stage of optimization. This design flow is designed to meet high standards for illumination uniformity, image quality, and color definition within the eye box.

Figure 2: Schematic diagram of the “right first time” design approach - designing with a manufacturing-aware SRG outline as the starting point

in conclusion

Incorporating "manufacturing awareness" into optical design, especially for meta-lenses and AR/VR devices, can help establish a robust and efficient optical design process. By understanding and simulating the impact of manufacturing processes on these devices, designers can improve product design performance and reduce design-manufacturing-testing cycles, thereby saving time and costs. As the demand for these devices continues to grow, this approach will play a key role in advancing optical and photonics technologies.