Cost-efficiency is a key performance indicator for maskshop operation. Laser mask writers are the preferred choice for all layers where they fulfill the requirements due to their lower cost. As a result, masks exposed by laser writers constitute for 70% of all masks used in semiconductor manufacturing. The industry relied for a long time on legacy equipment as applications matured, resulting in a challenge for stable and reliable mask manufacturing in mature design nodes. Mycronic addressed this gap by introducing the SLX series laser writer in 2019. As mask operations continue to strive for higher efficiency, Mycronic has increased the throughput of the SLX writers by utilizing “Meander writing”, which optimizes writing time by exposing on the return stroke of the writing sequence. This enables an increased throughput of the SLX of 20-30%. In this paper, Mycronic will share throughput and performance results from the SLX series by utilizing Meander writing.
The semiconductor industry is growing at an annual rate of 6.9%, and the production of semiconductor devices is increasing accordingly. Currently, device manufacturing using Extreme Ultraviolet (EUV), referred to as 2 nm technology, has begun for AI and mobile phone devices. On the other hand, the production of devices using >90nm technology, known as mainstream, for the automobile industry and sensing devices, including power, analog, and discrete, is also increasing, leading to an increase in the production of photomasks. However, the reality is that the production of photomasks for the relevant technology is using outdated equipment, and there is a need for equipment with high productivity. In this study, we investigate how e-beam masks for devices used in the mainstream technology compares to masks manufactured with current high-productivity DUV laser equipment and will focus on the following aspects and provide a comprehensive report. Comparison with manufactured masks based on current technologies in terms of CDU, Registration, resolution, printability and so on.
The high throughput time that can be achieved with laser-based lithography tools provide a tangible benefit for exposure of large areas with loose CD requirements. In this paper we present a recently developed DUV laser-based photolithography tool, supplied by Mycronic, that has been installed and qualified for optical and EUV lithography process at Intel Mask Operations. The tool utilizes a solid-state laser system for low power consumption and sustainable operation, modern electronics providing extensive logging capabilities, and an offline datapath that enables write times independent of pattern complexity. It also features multi-pass printing options that can be selected based on CD and REG requirements and throughput time, altogether providing flexibility and low cost of ownership. Tool specifications for critical dimensions and registration results will be presented in addition to tool matching and qualification data.
Mycronic assessed the market for Laser Mask Writers and concluded that there was an opportunity if the product was reliable, had high uptime, was cost-efficient to compete with fully depreciated writers and was sustainable including having a small carbon footprint. To achieve this, the platform needed to be modern allowing to support flexibility in a rapidly changing environment and enable the possibility to develop new functionalities to meet future customer demands to last long, while keeping the development cost down.
This paper describes the process and the decisions behind the SLX writer and how it has been received by the market. The future of the SLX will also be discussed and how key parameters like resolution and registration will be improved for future products.
Global semiconductor market is expected to have strong growth driven by various applications but suffering for the chip shortages. Tight supply is expected also in semiconductor photomask industry and the leading-edge photomask tend to have the most of the attention but concern increases in mature photomask supply chain coupled with aging photomask writers. Mycronic has introduced the SLX series to contribute solving existing issues design with sustainability profile. We will share the latest evaluation data from the system and share environmental impact of the SLX through LCA (Life Cycle Analysis).
The semiconductor industry is enjoying the “Semiconductor super cycle” catalyzed by the pandemic. In addition, the variety of semiconductor chips are increasing driven by electronification of everything resulting the demand for laser based mask writers are increasing due to lower exposure cost per mask. However, many laser mask writers in operation today are getting old.
As a response to the growing demand Mycronic introduced SLX series, a new generation cost-efficient laser mask writer and the superiority of the system is demonstrated by sharing recent evaluation data with two different laser sources.
A New Generation Cost-efficient Laser Mask Writer for
Mature Semiconductor Nodes
Mycronic introduces SLX series – a new generation cost-efficient laser mask writer – to meet the ever increasing demand for laser based photomask writer driven by new semiconductor trends such as “More than Moore” and “Electronification of everything”. Photomasks of mature design nodes are required due to large variety of designs combined with price-sensitive low volume manufacturing.
In this paper, Mycronic shares key technologies used in SLX series and how to achieve the cost effective mask manufacturing and demonstrates the superiority of the system by trecent evaluation data.
Managing the total CD error in advanced mask manufacturing requires that error contributions from writing, process and
metrology are minimized. This paper describes how both the writing and process contributions have been addressed in
the Sigma7500 DUV laser pattern generator, which prints masks by imaging a programmable spatial light modulator
(SLM). System enhancements have reduced the writing contribution to global CD uniformity to 5 nm (3s). Process-related
CD error sources, such as the signatures from mask developing and etching can be significant contributors to the
total CD error in mask manufacturing. These errors are classified as being either pattern-independent or pattern-dependent,
and the effects of both can be reduced using the ProcessEqualizer feature of the Sigma7500. This software
tool performs CD sizing during writing based on pattern density maps derived during mask data preparation, along with
tunable parameters that are determined experimentally. The CD sizing function has no effect on system throughput and
does not require flattening and re-fracturing of the pattern data.
Phase shift mask (PSM) applications are becoming essential for addressing the lithography requirements of the 65 nm technology node and beyond. Many mask writer properties must be under control to expose the second level of advanced PSM: second level alignment system accuracy, resolution, pattern fidelity, critical dimension (CD) uniformity and registration. Optical mask writers have the advantage of process simplicity for this application, as they do not require a discharge layer. This paper discusses how the mask writer properties affect the error budget for printing the second level. A deep ultraviolet (DUV) mask writer with a spatial light modulator (SLM) is used in the experimental part of the paper. Partially coherent imaging optics at the 248 nm wavelength provide improved resolution over previous systems, and pattern fidelity is optimized by a real-time corner enhancement function. Lithographic performance is compared to the requirements for second level exposure of advanced PSM. The results indicate sufficient capability and stability for 2nd level alternating PSM patterning at the 65 nm and 45 nm nodes.
Critical dimension control is becoming more and more critical in the mask making industry as the exposure wavelength goes down. For laser pattern generators, the move from traditional DNQ/Novolak based towards DUV chemically amplified resist processing was initially troublesome. The relative long total exposure time of pattern generators in contrast to wafer steppers, in combination with thick quartz substrates with relatively low heat capacity, may result in
reduced lithographic performance due to excessive diffusion of photogenerated acid. The photoresist polymer architecture play a large role in determining the acid diffusion characteristics and thereby also the image fidelity and resolution. In the Sigma7300 laser pattern generator the image is created by the spatial light modulator, which acts as a reflective computer-controlled reticle. By adopting a proper writing strategy, the negative effects of acid diffusion could be reduced. One component in the Sigma writing strategy is to expose the pattern in several passes that allows for dose compensation as well as averaging schemes to reduce CD errors. By adjusting the dose per pass and by keeping track of the delay times between each shot as well as the exposure path, a better control of the linewidth may be achieved for certain photoresist chemistry. In this study we present results from investigations of AZ DX 1100P and FEP-171 resists using different writing strategies.
The recently installed Sigma7100 laser pattern generator brings a new concept into photomask manufacturing. The spatial light modulator (SLM) technology enables 2D patterning using commercially available 248 nm lasers. This wavelength shift from the 413 nm wavelength of the Omega6000 scanning laser pattern generators facilitates the high resolution needed for 100 nm mask production. In addition, the partially coherence of the 2D patterning further enhances CD linearity and edge acuity. The rapidly increasing mask costs are partially attributed to increasing photomask writing times. These tend to increase as feature density increases with the roadmap, which is a challenge for any pattern generator with a limited number of writing beams. Instead, the SLM technology relies on the massive parallelism of one million micromirrors in combination with gray-scale control for fine addressing. A real-time FPGA-based data-rendering engine matches the speed. The result is pattern generation with high resolution at manageable mask writing times
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