• Title/Summary/Keyword: DFRs

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Formation of Fine Pitch Solder Bumps on Polytetrafluoroethylene Printed Circuit Board using Dry Film Photoresist (Dry Film Photoresist를 이용한 테프론 PCB 위 미세 피치 솔더 범프 형성)

  • Lee Jeong Seop;Ju Geon Mo;Jeon Deok Yeong
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.169-173
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    • 2003
  • We demonstrated the applicability of dry film photoresist (DFR) in photolithography process for fine pitch solder bumping on the polytetrafluoroethylene (PTFE/Teflon) printed circuit board (PCB). The copper lines were formed with $100\;{\mu}m$ width and $18\;{\mu}m$ thickness on the PTFE test board, and varying the gaps between two copper lines in a range of $100-200\;{\mu}m$. The DFRs of $15\;{\mu}m$ thickness were laminated by hot roll laminator, by varying laminating temperature from $100^{\circ}C\;to\;150^{\circ}C$ and laminating speed. We found the optimum process of DFR lamination on PTFE PCB and accomplished the formation of indium solder bumps. The optimum lamination condition was temperature of $150^{\circ}C$ and speed of about 0.63 cm/s. And the smallest size of indium solder bump was diameter of $50\;{\mu}m$ with pitch of $100\;{\mu}m$.

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Residues and Half-lives of Bitertanol and Tebuconazole in Greenhouse-Grown Peppers (시설재배 고추중 Bitertanol 및 Tebuconazole 잔류양상)

  • Seong, Ki-Yong;Jeong, Mong-Hee;Hur, Jang-Hyun;Kim, Jeong-Gyu;Lee, Kyu-Seung;Choi, Kyu-Il
    • Applied Biological Chemistry
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    • v.47 no.1
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    • pp.113-119
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    • 2004
  • Persistence of the triazole fungicides, bitertanol and tebucnazole was investigated after their application at recommended and double rate on greenhouse-grown peppers. The half-life of bitertanol and tebuconazole on peppers at recommended and double rate was $5.2{\sim}6.1$ and $4.6{\sim}5.2$ days, respectively. Half-lives of bitertanol and tebuconazole on pepper leaves $(16.8{\sim}22.5\;days)$ was longer than those in the peppers. Residual concentration of bitertanol and tebuconazole on pepper leaves 24 days after application were 10.1 and 17.5 mg/kg, respectively, and these levels were higher than MRL which had been established at 3.0 and 5.0 mg/kg in Korea. Pattern of dissipation was well fitted to the first-order kinetics. In household washing experiment with surfactant, dislodgeable portions on pepper leaves of bitertanol and tebuconazole were occupied 36% and 48% of the residues found 24 days after application.

Low Complexity Subcarrier Allocation Scheme for OFDMA Systems (OFDMA 시스템을 위한 저 복잡도 부반송파 할당기법)

  • Woo, Choong-Chae;Wang, Han-Ho
    • Journal of the Institute of Convergence Signal Processing
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    • v.13 no.2
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    • pp.99-105
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    • 2012
  • The focus of this paper is a proposal for a computationally efficient dynamic subcarrier allocation (DSA) algorithm for orthogonal frequency-division multiple access (OFDMA) systems. The proposed DSA algorithm considerably reduces the computational complexity and the amount of channel quality information (CQI) compared to amplitude craving greedy (ACG) algorithms, which use full CQI. At the same time, the performance of the proposed algorithm closely appear to ACG algorithms. Moreover, the authors present a new bandwidth-assignment algorithm produced by modifying bandwidth assignment based on the signal-to-noise ratio (BABS). This modified BABS algorithm enables the proposed DSA algorithm to produce a strong outage performance gain over the conventional scheme.

Formation of Fine Pitch Solder Bumps on Polytetrafluoroethylene Printed Circuit Board using Dry Film Photoresist (Dry Film Photoresist를 이용한 테프론 PCB 위 미세 피치 솔더 범프 형성)

  • 이정섭;주건모;전덕영
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.1
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    • pp.21-28
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    • 2004
  • We have demonstrated the applicability of dry film photoresist (DFR) in photolithography process for fine pitch solder bumping on the polytetrafluoroethylene (PTFE/Teflon ) printed circuit board (PCB). The copper lines were formed with 100$\mu\textrm{m}$ width and 18$\mu\textrm{m}$ thickness on the PTFE test board, and varying the gaps between two copper lines in a range of 100-200$\mu\textrm{m}$. The DFRs of 15$\mu\textrm{m}$ thickness were laminated by hot roll laminator, by varying laminating temperature from $100{\circ}C$ to 15$0^{\circ}C$ and laminating speed from 0.28-0.98cm/s. We have found the optimum process of DFR lamination on PTFE PCB and accomplished the formation of indium solder bumps. The optimum lamination condition was temperature of $150^{\circ}C$ and speed of about 0.63cm/s. And the smallest size of indium solder bump was diameter of 50$\mu\textrm{m}$ with pitch of 100$\mu\textrm{m}$.

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