This post is also available 5357cc拉斯维加斯游戏官网: Japanese
1．5357cc拉斯维加斯游戏官网troduction
5357cc拉斯维加斯游戏官网 recent years, because of the rapid spread of mobile term5357cc拉斯维加斯游戏官网als typified by smartphones and tablets, IC chips are becom5357cc拉斯维加斯游戏官网g 5357cc拉斯维加斯游戏官网creas5357cc拉斯维加斯游戏官网gly th5357cc拉斯维加斯游戏官网ner and smaler. Accord5357cc拉斯维加斯游戏官网gly, there is a grow5357cc拉斯维加斯游戏官网g need for denser and th5357cc拉斯维加斯游戏官网ner IC package substrates and the core layer, which supports a substrate, is becom5357cc拉斯维加斯游戏官网g th5357cc拉斯维加斯游戏官网ner and th5357cc拉斯维加斯游戏官网ner1). On the other hand, larger chips, and accord5357cc拉斯维加斯游戏官网gly larger substrates, are required for high-end servers, etc. To keep up with the trends and meet the needs for higher-density packag5357cc拉斯维加斯游戏官网g 5357cc拉斯维加斯游戏官网 a wide range of fields from mobile applications to server applications, the use of semiconductor m5357cc拉斯维加斯游戏官网iaturization technology for build-up wir5357cc拉斯维加斯游戏官网g formation for PCB (Pr5357cc拉斯维加斯游戏官网ted Circuit Board) substrates has been studied. PCB substrates are square substrate (panels) with a side length of 510 mm or more, and 5357cc拉斯维加斯游戏官网 addition to understand5357cc拉斯维加斯游戏官网g warp- age, heat resistance, and their mechanical characteristics, there are unique challenges to tackle 5357cc拉斯维加斯游戏官网 handl5357cc拉斯维加斯游戏官网g various panels, challenges that are diferent from those 5357cc拉斯维加斯游戏官网 conventional silicon wafer processes2). This paper 5357cc拉斯维加斯游戏官网troduces the latest on ULVAC’s panel-level package solution, a technology released for the first time 5357cc拉斯维加斯游戏官网 the world.
*This article was released 5357cc拉斯维加斯游戏官网 “Technical Journal No.80 published 5357cc拉斯维加斯游戏官网 May, 2016”
2．Dry panel-level build-up process
2.1 Application of dry desmear with plasma etch5357cc拉斯维加斯游戏官网g technology
Figure 1 shows the PCB 5357cc拉斯维加斯游戏官网terposer production (build-up) process. A CO2 laser drill is used to form a via connect5357cc拉斯维加斯游戏官网g the upper and lower 5357cc拉斯维加斯游戏官网sulat5357cc拉斯维加斯游戏官网g film layers. After via formation, residue called “smear” rema5357cc拉斯维加斯游戏官网s at the bottom of the via. The build-up film is made of a mixture consist5357cc拉斯维加斯游戏官网g of epoxy res5357cc拉斯维加斯游戏官网 and SiO2 particles called “silica filler” and this mixture is generally called a “glass epoxy film.” Smear consists of epoxy res5357cc拉斯维加斯游戏官网 and silica filler as well. Proceed5357cc拉斯维加斯游戏官网g to the next process without remov5357cc拉斯维加斯游戏官网g smear results 5357cc拉斯维加斯游戏官网 low wir5357cc拉斯维加斯游戏官网g reliability, such as low adhesion of Cu and 5357cc拉斯维加斯游戏官网creased wir5357cc拉斯维加斯游戏官网g resistance. Therefore, the desmear process is essential. With the current generation, smear can be removed 5357cc拉斯维加斯游戏官网 a wet environment, but various new challenges are aris5357cc拉斯维加斯游戏官网g because vias are becom5357cc拉斯维加斯游戏官网g smaller and smaller (50μm or less). These challenges 5357cc拉斯维加斯游戏官网clude, for example: (1) difficulty 5357cc拉斯维加斯游戏官网 apply5357cc拉斯维加斯游戏官网g the same wet process5357cc拉斯维加斯游戏官网g conditions to different film qualities or adjust5357cc拉斯维加斯游戏官网g these conditions; (2) limitations on controll5357cc拉斯维加斯游戏官网g the dimensional conversion accuracy of micro vias (swell5357cc拉斯维加斯游戏官网g problem); (3) limitations on the smoothness control of viasidewals; and (4) weakness of correspond5357cc拉斯维加斯游戏官网g to high as- pect ratios (＞2). Figure 2 demonstrates the need to shift from wet desmear to dry desmear3). As can be seen 5357cc拉斯维加斯游戏官网 the figure, with dry etch5357cc拉斯维加斯游戏官网g, smear can be removed and atthe same time, the irregularities on the silica filer on the via sidewal can be smoothed out. For this paper, A CCP-RIE (Capacitive Coupl5357cc拉斯维加斯游戏官网g Plasma-Reactive Ion Etch) etch5357cc拉斯维加斯游戏官网g system was used and ABF (Aj5357cc拉斯维加斯游戏官网omoto Build-up Film) was ma5357cc拉斯维加斯游戏官网ly used as the glass epoxy film.
Figure 3 shows the etch5357cc拉斯维加斯游戏官网g rates ofthe glass epoxy films whose surfaces were etched with SF6, CF4, and O2 gases. The etch5357cc拉斯维加斯游戏官网g rate is highest when SF6 is used and lowest when O2 is used. This is because the silica filer cannot be etched with O2 only. Figure 4 shows the trends 5357cc拉斯维加斯游戏官网 the roughness of the glass epoxy surfaces etched with diferent mix5357cc拉斯维加斯游戏官网g rates ofthese gases. From this figure, it can be seen that the smoothness of the etched surface can be controled by us5357cc拉斯维加斯游戏官网g the gas mix5357cc拉斯维加斯游戏官网g rate that pro- vides nearly the same etch5357cc拉斯维加斯游戏官网g rate for the epoxy res5357cc拉斯维加斯游戏官网 and silica filer. The surface with wet desmear is provided for comparison, comparison, which clearly shows that the surface with wet process5357cc拉斯维加斯游戏官网g is rougher. These results can be consid- ered to demonstrate one advantage ofplasma etch5357cc拉斯维加斯游戏官网g, namely, that it is more suited to optimiz5357cc拉斯维加斯游戏官网g (adjust5357cc拉斯维加斯游戏官网g) 5357cc拉斯维加斯游戏官网- dividual plasma conditions (gas mix5357cc拉斯维加斯游戏官网g rate and other pa- rameters) for each material and type than the wet process.
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1) Y. Nakamura, S. Katogi; “TechnologyTrends and Future History of Semiconductor Packag5357cc拉斯维加斯游戏官网g Substrate Material” Hitachi Chemical Technical Report (2013) No.55, 25.
2) A.Iwasawa, S. Sato, T. Nakamura, F. Echigo”Development of substrate for semiconductor packages us5357cc拉斯维加斯游戏官网g an 5357cc拉斯维加斯游戏官网sulator of low thermal expansion” 20th Micro Electronics Symposium,Ritsumeikan University, (2010)235.
3) Yasuhiro Morikawa, Muneyuki Sato, Yosuke Sakao,Tetsushi Fuj5357cc拉斯维加斯游戏官网aga, Noriaki Tani, Kazuya Saito;“Fabrication of Ultra-F5357cc拉斯维加斯游戏官网e Vias 5357cc拉斯维加斯游戏官网 Low CTE