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 However, the reality is that the production of photomasks for the relevant technology is using outdated equipment, and there is a need for equipment with high productivity.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.
A strategy for sub-100 nm technology nodes is to maximize the use of high-speed deep-UV laser pattern generators, reserving e-beam tools for the most critical photomask layers. With a 248 nm excimer laser and 0.82 NA projection optics, the Sigma7500 increases the application space of laser pattern generators. A programmable spatial light modulator (SLM) is imaged with partially coherent optics to compose the photomask pattern. Image profiles are enhanced with phase shifting in the pattern generator, and features below 200 nm are reliably printed. The Sigma7500 extends the SLM-based architecture with improvements to CD uniformity and placement accuracy, resulting from an error budget-based methodology. Among these improvements is a stiffer focus stage design with digital servos, resulting in improved focus stability. Tighter climate controls and improved dose control reduce drift during mask patterning. As a result, global composite CD uniformity below 5 nm (3σ) has been demonstrated, with placement accuracy below 10 nm (3σ) across the mask. Self-calibration methods are used to optimize and monitor system performance, reducing the need to print test plates. The SLM calibration camera views programmed test patterns, making it possible to evaluate image metrics such as CD uniformity and line edge roughness. The camera is also used to characterize image placement over the optical field. A feature called ProcessEqualizerTM has been developed to correct long-range CD errors arising from process effects on production photomasks. Mask data is sized in real time to compensate for pattern-dependent errors related to local pattern density, as well as for systematic pattern-independent errors such as radial CD signatures. Corrections are made in the pixel domain in the advanced adjustments processor, which also performs global biasing, stamp distortion compensation, and corner enhancement. In the Sigma7500, the mask pattern is imaged with full edge addressability in each writing pass, providing the means of additionally improving write time by reducing the number of exposure passes. Photomask write time is generally under two hours in the 2-pass mode, compared to three hours with 4-pass writing. With a through-the-lens alignment system and both grid matching and pattern matching capabilities, the tool is also suitable for 2nd layer patterning in advanced PSM applications. Improvements in alignment algorithms and writing accuracy have resulted in first-to-second level overlay below 15 nm (mean+3σ).
As photomask pattern complexity continues to increase, it becomes more challenging to control write times of shaped e-beam tools. This raises the related concerns of increased mask costs and extended mask cycle times. A strategy for sub-100 nm technology nodes is to use high-speed DUV laser pattern generators for as many layers as possible, reserving e-beam tools for only the most critical layers. With 248 nm optics and high-NA partially coherent imaging, the Sigma7500 increases the application space available to laser pattern generators. Image profiles are steepened with phase shifting methods, and pattern fidelity is improved with on-line corner enhancement. In the Sigma architecture, mask patterns are imaged with full fidelity and addressability in each writing pass. Because of this, the Sigma7500 provides additional means to improve write time by reducing the number of exposure passes. Platform improvements have resulted in a 2-pass writing accuracy that meets the 4-pass specification of the previous system. Write time is typically under two hours in 2-pass mode, compared to approximately three hours for 4-pass. The Sigma7500 can generally be used for all binary mask layers at the 90 nm technology node, and for about half the layers at 45 nm. The ProcessEqualizerTM function addresses long range CD errors arising from mask process effects. Mask data is sized in real time to compensate for process errors related to local pattern density, and also to correct for static process CD signatures. With a through-the-lens alignment system and both grid matching and pattern matching capabilities, the tool is also suited to 2nd layer patterning for advanced phase shifting mask (PSM) applications down to 45 nm, with extendibility to 32 nm. Process integration is facilitated by the use of standard FEP-171 chemically amplified resist (CAR).
This paper presents the properties of a second-generation DUV laser pattern generator based on spatial light modulator technology and designed to meet the requirements of the 90-nm to 65-nm technology nodes. The system, named Sigma7300, is described and major changes compared to its predecessor are pointed out. These changes result in improved pattern accuracy and fidelity as well as system reliability and maintenance. This improved performance is accompanied with greatly reduced writing times of typically 3 Hrs. per mask. Performance data is presented that shows the system meets the resolution requirement of 260 nm with CD linearity of 10 nm and assist line resolution of 140 nm. CD uniformity data and registration data are also presented that indicates that the system meets the requirements for most layers at the 90-nm and 65-nm nodes.
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
Sigma7100 is a revolutionary new architecture for Laser Pattern Generators being developed by Micronic Laser Systems. The Sigma7100 system design uses a unique architecture based on a spatial light modulator (SLM), a MEMS consisting of a 1 million pixel micro-mirror array fabricated onto a CMOS substrate. The SLM functions as a dynamic mask which is illuminated by a 1kHz DUV excimer laser. A new pattern is calculated and downloaded into the SLM for each laser pulse, and the resultant SLM image is then projected on to the mask substrate. This paper describes the Sigma7100 architecture, presents recent results, and presents a look into the path toward extending the SLM technology to the 70nm node and beyond.
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