Market Survey on Screen Printers 2018-TaiyangNews.pdf

Market Survey Screen Printers 2018 Authors: Shravan K. Chunduri, Michael Schmela 2 TaiyangNews | Screen Printers 2018 Contents © TaiyangNews 2018 All rights reserved. The text, photos and graphs in this report are copyrighted (cover photo credit: Formula E). TaiyangNews does not guarantee reliability, accuracy or completeness of this report s content. TaiyangNews does not accept responsibility or liability for any errors in this work. Publisher: TaiyangNews UG (haftungsbeschraenkt) Montsalvatstr. 15 80804 Munich, Germany www.taiyangnews.info 01 Introduction Click on the chapter you want to explore. 03 Advanced Metallization Concepts 04 Product Details 02 Overview • Basics of Screen and Printing • Metallization Review • Improvements in Screen Printing • Screen Printer Suppliers • Market Update • Fundamentals of Metallization • Double Printing • Dual Printing • Stencil Screens • Knotless Screens • Other Developments 06 Conclusions 05 Advanced Printing Technologies • Rotary Screen Printing • Flexographic Printing • Parallel Dispensing 07 Product Specifications Table 6 7 15 23 27 30 31 • DK Electronic Materials (DKEM) p.3 • Heraeus p.5 • SNEC p.13 • SolarPower Europe p.19 Advertisers:3 TaiyangNews | Screen Printers 2018 Stronger. Together. Embrace the Advanced PERC & Interconnection Era Industry Leading Supplier of PV Silver Paste Visit us at: SNEC 2018 | Shanghai, China | 28 th -30 th , May | Booth W4-598 DK Electronic Materials, Inc. | www.dkem.cn | info@dkem.cn DKEM™ When Performance Matters™ offers High Performance PV Silver Paste Breakthrough on Metallization for the Dual-side Passivation Process of AlOx to Lead the Diversified PERC Technologies with Superior Compatibility All-new Top-down Design of Silver Paste to Boost the Power of Multi-Busbar and Shingled Modules Beyond the Expected 400W Innovator to Redefine Metallization Strategy with Synergy between Advanced Cell and Module Technology4 TaiyangNews | Screen Printers 2018 Metallization is an important process sequence in solar cell manufacturing that not only influences cell performance, but also manufacturing costs. Often metallization is also one important production step that requires adaptation when moving to new cell architectures. While several technologies have been developed for cell metallization, screen printing has remained the only game in town for this purpose. For our first market survey on screen printers, 5 companies have responded to our enquiry and provided data for 7 products. Regarding tools, manufacturers have been primarily focusing on throughput. The products listed in our survey can process between 1,600 and 5,200 wafers per hour. Regarding process, reducing screen opening and thus the finger width, as well as paste laydown are the hottest topics. Finger dimensions in mass production are now between 45 and 50 µm with an aspect ratio ranging from 0.2 to 0.5 and realized with 28 to 35 µm screen openings. Paste consumption ranges between 90 to 100 mg on the front side. In order to improve cell contact application further, screen printer suppliers are working on different advanced metallization concepts. Double printing, dual printing and stencil printing are well known – employing knotless printing is the latest trend. While double printing is the most widely employed advanced metallization approach today, it is expected to continue increasing its share until any other technology can provide equal or higher benefits. Knotless screen technology is one promising alternative, but it is not yet widespread. Dual printing needs to reduce paste consumption, but few use it. Knotless in combination with dual printing has several advantages, in particular for cell makers with double printing in place that want to upgrade their lines. Stencil printing has not been a big hit so far, but if stable and low cost products become available this may change. In addition to these advanced printing technologies, screen printer suppliers are also developing solutions for advanced cell and module architectures. Equipment makers are developing solutions with high printing accuracy, not only required for double printing, but also helpful for selective emitters to combine with PERC and rear side metallization of bifacial PERC cells. Screen printer makers are also offering metallization solutions for heterojunction technology, which requires a fairly different metallization regime over the standard. In addition to providing an insight of screen printing based metallization, our survey on screen printers also provides a brief overview on alternative printing technologies under development, such as rotary printing, flexographic printing and dispensing , which demonstrated encouraging first results. t Enjoy reading our Market Survey on Screen Printers 2018 Shravan K. Chunduri Head of Technology, TaiyangNews shravan.chunduri@taiyangnews.info +91 996 327 0005 Hyderabad, India Michael Schmela Managing Director, TaiyangNews michael.schmela@taiyangnews.info +49 173 15 70 999 Munich, Germany Executive Summary5 TaiyangNews | Screen Printers 2018 Wisdom creates efficiency. Our Research and Development team is constantly thinking about paste. We are committed to developing leading-edge solutions, which improve the power output and performance of solar cells at a lower cost per watt. We are always mindful of the current and future technology needs of our customers, and are driven to deliver results. So when you think of paste.think of Heraeus. Leadership through R&D. Breakthroughs via innovation. Achievement by tradition. Visit us at: SNEC | Booth W3-510 | Shanghai, China | May 28 th - 30 th , 2018 Heraeus Photovoltaics Global Business Unit www.heraeus-photovoltaics.com China | Singapore | Taiwan | Europe | America | Japan Metallisation Survey_216x303_03-02-2018_EN.indd 1 3/2/18 9:29 PM6 TaiyangNews | Screen Printers 2018 1. Introduction A silicon wafer is converted into a solar cell already after junction formation, but the silicon slices are usually referred to as wafers until metallization is completed. In other words – metallization is the process that actually turns the silicon substrate into a fully functioning cell. The metallization process involves two steps – depositing metallic contacts onto both sides of the wafer and sintering them into silicon, which enables collection of the generated charge carriers. After the metallization process, solar cells are ready for series connection in module manufacturing. Solar cell metallization is one of the most important cell manufacturing steps that not only influences a solar cell’s output power, it also has great impact on manufacturing costs. While metallization requires optimization when moving to any high-efficiency cell architecture, a few advanced cell concepts even need different ways to apply the metallic contacts. Developments in metallization are a collective effort in process materials (metallization pastes) and production equipment (screens, screen printers, firing furnaces). While we took a close look on paste developments in our TaiyangNews Market Survey on Metallization Pastes 2017 (which will be updated in April 2018), this survey focuses on – screen printing equipment, providing an overview on the different models as well as the latest news on screens, which are an important constituent of the printing tools. Our survey also provides an update on advanced metallization approaches that might challenge screen printing technology in the future. Source: Applied Materials Backend line: Screen printer suppliers often offer their printing line (left) together with testing and sorting solutions (right) as a full backend line. Source: Applied Materials7 TaiyangNews | Screen Printers 2018 Screen printers have been the workhorses for the metallization process since the beginning of crystalline solar cell production. In a typical cell manufacturing line, screen printers are integrated with ‘inter-tool’ transportation systems, dryers, buffers, various inspection systems as well as a firing furnace and a IV testing & sorting device. This completely integrated and automated setup is usually referred to as ‘backend line.’ Screen printer suppliers are often offering such fully integrated backend lines. 2.1 Screen Printers Suppliers The 5 companies that have responded to our enquiry are offering both single tools and full back-end lines. Our first market survey on screen printers lists 7 products from 5 different companies: • ASYS Group, Germany • Baccini Cell Systems, a division of Applied Materials, USA • Formula E s.r. l., Italy • JRT Photovoltaics GmbH & Co. KG, Germany • Micro-tec Co., Ltd., Japan ASYS from Germany and US based Applied Materials are well known in the screen printers business and have been leaders in this solar cells production equipment segment for many years. While Formula E is a new company, its founders have been in the screen printing business for a long time as well. The Italian company was started in 2013 by former heads of Baccini, which was taken over by Applied Materials to access screen printing over a decade ago. Formula E started offering a module assembly line for backcontact modules but has quickly expanded into building metallization lines. Now, Formula E is having in its product portfolio basically all sub-systems of a metallization line, including screen printers, loaders, dryers, testers and sorters, except for the firing furnace. This is also true for ASYS, Applied Materials and JRT. Micro-tec is even of fering a firing furnace as part of its backend solution. 2.2 Market Update Historically, the screen printing business had been the domain of European equipment vendors. But – as with any other segment in the PV value chain – established western and Japanese metallization equipment suppliers are facing an increasing competition from local suppliers in China, which offer their products at much lower prices than the former incumbents. While the metallization tools from Chinese suppliers are still mostly rather simple machine platforms and transportation systems, they are doing their job and are quite fast, at least for standard solar cell processing. As the installed base quickly grows so does the knowledge of Asian tool makers, resulting in higher quality and more advanced printing systems. Maxwell is one such Chinese company that has installed many screen printers in fabs of many Chinese cell makers. But neither Maxwell nor any other Chinese supplier has answered our questionnaire. DEK, a British company and one of the established though smaller screen printer suppliers from Europe, was taken over by ASM Assembly Systems in 2013, however, it has not responded to our inquiry for this survey either. Regarding market conditions, the survey participants are generally satisfied. The strongly growing solar market to over 95 GW in 2017 has been pushing our customers to add capacity, said Giorgio Cellere, head of product management at Applied Materials. “We have a number of customers who are upgrading in terms of technology, sizing or geographical location, all put together fueling to add more capacities” he said. As for the market share, Applied Materials claims it is still “among the market leaders” and by far ranked #1 in terms of installed systems. 2. Overview8 TaiyangNews | Screen Printers 2018 ASYS was also a world leading supplier of screen printers for a long time, but the situation has changed over the last 2 years. Like any other company in this survey, ASYS is also facing huge price pressure and tough competition from Chinese vendors of screen- printing tools in the area of high volume standard solar cell production. However, new technologies that are coming up in solar are offering a chance to technically advanced solutions, said Erwin Beck, Senior Vice President at ASYS. Formula E is still in the starting phase, but the first deals are done. “W e have finalized projects in T aiwan and in China,” said Paul Kasulke, business head of Formula E. “Many new projects are in the pipeline,” he added. In summary, it is no surprise that these three equipment makers are mainly focusing on developing high-end metallization solutions, because this will be the only chance to compete with low-cost Chinese suppliers. However, before going into product details, we provide first some basics of screen printing. 2.3 Fundamentals of Metallization Crystalline silicon solar cell manufacturing typically requires three screen printers – one for depositing fingers and busbars on the front side, one for applying aluminum for rear contact and back surface field (BSF) layers, and one for depositing rear tabbing busbars. The number of printers required in a cell line can increase depending on the metallization technology. For example, both double and dual printing require four printers. After each of these printing steps, the wafers pass through dryers to solidify the pastes. When all required metallic patterns are applied, the deposited metal is sintered into the silicon in a step called co-firing, which is accomplished in firing furnaces. Finally , the fully processed cells are tested for their electrical parameters and sorted according to their grades in a cell tester & sorter. As mentioned above, all screen printer suppliers listed in this survey are also offering integrated solutions to accomplish the complete backend process. Source: ASYS Schematic of Traditional Backend Cell Processing Line 9 TaiyangNews | Screen Printers 2018 2.4 Basics of Screens and Printing A screen printer consists of positioning systems, printing table, a printing head and a screen. All are integral parts of the printing tool, except for the screen, which is a process consumable, although a crucial one as it has considerable influence on the outcome of the printing process. A stainless steel mesh based screen mounted in a metallic frame is typically used for screen printing. Emulsion is added over the mesh of the screen in order to define the open areas in the form of desired contact patterns. The emulsion is a UV imageable material, which allows freely designing the patterns by exposing the screen to UV light. During the patterning process, a photo positive that has the shape of the desired contact pattern is placed in front of the emulsion in order to block the light during UV exposure. As a result, the shadowed area is prevented from hardening, so that it can be washed away subsequently, thus forming the open area in the desired contact pattern. The mesh wire diameter is an important attribute of the mesh – the smaller the diameter, the better it is for the cell metallization process, specifically for front contact formation. A mesh with a smaller mesh wire diameter facilitates a large open area and high screen tension, both of which favours the solar cell metallization process. On the other hand, a smaller wire diameter results in lower height of the deposited grid, which is an undesired outcome. Emulsion comes to