As expanding the market of microfluidics / microstructure devices in the biotechnology or life science fields, the demand for development of high volume manufacturing technique has been increasing. As one of the solutions, we have been developing a process to fabricate these devices on larger-format glass substrates.
In our previous study [1] [2], we reported wet etched glass mold for solder bumping technology which is called "C4NP". The glass mold requires very precisely controllable etching technique. We achieved high accuracy and good uniformity pattern with wet etching in 300 mm whole wafer.
In this study, we applied this etching technique to biotechnology or life science applications. In addition, we combined wet etching, micro-blast for through-hole and direct bonding techniques to make prototype microfluidics devices on larger-format glass substrates.
The following glass substrates were used for capillary plates シャッフルカジノ ベガウォレットrough-hole plates of the prototype microfluidics plate.
Material: Corning EAGLE XG
Size: 330.2 mm x 355.6 mm (13" x 14") x 0.7 mm (thickness)
EAGLE XG is one of the most popular glasses for flat panel displays. It is formed by Fusion down draw method therefore clean and smooth surface is formed. These glass substrates were cleaned with detergent and rinsed with DI water before processing. Table 1 shows the process flow.
To fabricate capillary plates, DC inline sputtering machine was used for Cr coating. This Cr film is optimized for HF etching to reduce defects. Then photolithography was used to make capillary pattern etching mask.
The capillary plates were etched to 40 um depth and 100 um width by dipping type etcher. Oscillation and circulation are controlled to improve uniformity over the whole substrate. Also the composition of HF based etchant is optimized for the glass type. Uniform map (see Fig 1) and uniform distribution of capillary depth was obtained (see Fig 2). The depth of 3sigma was 3% (1.2 um) シャッフルカジノ ベガウォレットe width of 3sigma was 3% (2.5um).
Through-holes were made by micro-blasting method. Dry-film photoresist was used for micro-blasting mask. The blast nozzle scans over whole pattern area and digs holes. When the diameter reaches the target value, micro-blast process was stopped.
Mask materials were removed from capillary plates シャッフルカジノ ベガウォレットrough-hole plates, and both plates were cleaned again. Bonding process was operated under clean benches to reduce particle. Through-holes and etching pattern alignment marks were used to align, シャッフルカジノ ベガウォレットen both plates were bonded temporarily. After temporarily bonding, the plate was baked and permanently bonded. (see Figs 3 and 4)
Fabricating microfluidics chip array on 13 x 14 inch large glass substrates was succeeded. We propose this technology as a solution for High Volume Manufacturing of microfluidics / microstructure devices.
References
[1] "Lead Free Micro Bumping - Cost & Yield Challenges" K. Ruhmer, E. Hughlett, M. Ishizuka, T. Kojima, T. Asaka, B. Dang, A. Buchwalter, D.Shih, EPTC 2007, Singapore, December 2007.
[2] "Fine Pitch Lead Free Solder Bumping with C4NP" K. Ruhmer, E. Laine, M. Ishizuka, T. Kojima, T. Asaka, Semicon Europe Advanced Packaging Conference, Stuttgart, October 2007.
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The market for lithium-ion batteries (LiBs) is expected to grow rapidly due to their use in a wide range of applications, such as smartphones, drones, and electric vehicles (EVs).In the automotive market, emissions regulations are being tightened in major countries, as exemplified by Euro 7 in Europe, the Zero-Emissions Vehicle (ZEV) regulations being strengthened in California, and China moving toward the New Energy Vehicle (NEV) regulations. It is becoming difficult for conventional engine technologies based on use of fossil fuels to comply with these regulations. For this reason, automakers are beginning to shift their focus toward popularizing EVs and plug-in hybrid (PHV or PHEV) vehicles1).
According to a survey by a think tank, more than 60 million EVs and PHVs are expected to be sold globally in 20402), シャッフルカジノ ベガウォレットe demand for battery capacity is also expected to surge. Consequently, there is a pressing need to enhance production facilities and develop large-capacity batteries, with battery makers competing furiously toward commercialization of the technology.
＊This article appeared in the September 2019 issue of the technical journal No. 83.
Anodes in LiBs
Current LiBs and next-generation LiBs using an Li metal anode
An LiB has a structure in which a cathode, an anode, and a separator are stacked and immersed in an electrolyte, as shown in Figure 1. As mentioned above, development efforts related to the materials and manufacturing methods of the various components are underway to increase battery capacity. Currently, a graphite-coated film is used for the anode, with a theoretical energy density of 370 mAh/g.Replacing this graphite anode with a material that has greater energy density would increase battery capacity3). In particular, it is considered ideal to switch to an Li metal anode with a theoretical energy density of 3860 mAh/g, which is gaining attention as a likely next-generation anode.LiB
Issues facing an anode using roll-press Li foil
Although Li metal is ideal for increasing capacity, it has issues in terms of safety and service life. These issues are presumed to be caused by dendrites, which are needleshaped precipitations of Li metal that occur over the life of repeated charging/discharging cycles4). As these dendrites grow, they cause short circuiting between the cathode シャッフルカジノ ベガウォレットe anode, potentially causing a fire, etc. Additionally, as shown in Figure 2, Li that does not enable charging/ discharging occurs, called "dead Li" because it falls off during the growth stage, posing an issue in terms of battery life5). It is said that dendrites are caused by the current concentration that occurs on the anode during charging6), and it is considered that flattening the Li surface and forming a uniform passivation film at the same time could improve the current distribution, thereby suppressing the formation of dendrites.
You can download full article with your registration/r_d/technical_journal/tj83j/
References
1) Mizuho Bank Industry Research Division: Mizuho Industry Focus 205, 11 (2018) (in Japanese).2) New Energy and Industrial Technology Development Organization: Focus NEDO 69, 9 (2018).3) New Energy and Industrial Technology Development Organization: NEDO Technology Roadmap for Stationary Battery 2013 (Battery RM2013), 10 (2013) (in Japanese).4) Electrochemical Society of Japan, Committee of Battery Technology, Battery Handbook (Ohmsha, 2010), p. 58 (in Japanese).5) Xin-Bing Cheng, Rui Zhang, Chen-Zi Zhao, and Qiang Zhang: Chemical Reviews, 117, 10406 (2017).6) Kiyoshi Kanamura, Naohiro Kobori, and Hirokazu Munakata: BLIX, Symposium on Energy Storage, San Jose (2017), p. 6.
