• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.4
• /
• pp.151-159
• /
• 2015

In this study, we developed an automated contact-type thickness measurement machine that continuously and precisely measures the thickness of a PCB module product using multi-LVDT sensors. The system contains a measurement part to automatically measure the thickness in real time according to the set conditions with an alignment supply unit and unloading unit to separate OK and NG products. The sensors were calibrated before assembly in the measuring machine, and precision and accuracy performance tests were also performed to reduce uncertainty errors in the measurement machine. In the calibration test, the precision errors of the LVDT sensor were determined to be $1-3{\mu}m$ as 0.1% at the measuring range. A measurement error of 0.8 mm and 1.0 mm thickness test standards were found to be $1{\mu}m$ and $4{\mu}m$, and the standard deviations of two 1.0 mm products were measured as $14{\mu}m$ and $8{\mu}m$, respectively. In the measurement system analysis, the accuracies of test PCB standards were found to be $2{\mu}m$ and $3{\mu}m$, respectively. From the results of gage repeatability and reproducibility (R & R) crossed, we found that the machine is suitable for the measurement and process control in the mass production line as 7.92% of total gage R & R and in seven distinct categories. The maximum operating speed was limited at 13 pcs/min, showing a value good enough to measure.

• 한국생물공학회:학술대회논문집
• /
• 2004.07a
• /
• pp.1-20
• /
• 2004

Polychlorinated biphenyls (PCBs), one a group of persistent and widespread environmental pollutants, have been considered to be involved in immunotoxicity, carcinogenesis, and apoptosis. However, the toxic effects and physical properties of a PCB congener are dependent on the structure. In the present study, we investigate the toxic effects and action mechanisms of PCBs In cells. Among the various congeners tested, 2,2',4,6,6'-PeCB-pentachlorobiphenyl (PeCB), a highly ortho-substituted congener having negligible binding affinity for aryl hydrocarbon receptor (AhR), caused the most potent toxicity and specific effects in several cell types. 2,2',4,6,6'-PeCB induced apoptotic cell death of human monocytic cells, suggesting that PCB-induced apoptosis may be linked to immunotoxicity. In addition, 2,2',4,6,6'-PeCB induced mitotic arrest by interfering with mitotic spindle assembly in NIH3T3 fibroblasts, followed by genetic instability which triggers p53 activation. Which suggests that 2,2',4,6,6'-PeCB may be involved in cancer development by causing genetic instability through mitotic spindle damage. On the other hand, 2,2',4,6,6'-PeCB increased cyclooxygenase-2 (COX-2) involved in cell survival through ERK1/2 MAPK and p53 in Rat-1 fibroblasts and mouse embryonic fibroblasts, triggering compensatory mechanism for abating its toxicity. Taken together, these results demonstrate that PCB congeners of different structure have distinct mechanism of action and 2,2',4,6,6'-PeCB causes several toxicity as well as compensatory mechanism in cells.

• Proceedings of the KIEE Conference
• /
• 1991.07a
• /
• pp.47-50
• /
• 1991

LPM(Linear Pulse Motor) provide direct and precise position control of bidirectional linear motion. LPM is not subject to the same linear velocity and acceleration limitations inherent in systems converting rotary to linear motion such as lead screws, rack and pinion, belt and pulley drives. With LPM, all the thrust force generated by the motor is efficiently applied directly to the load. And speed, distance, and acceleration are easily programmed in a highly repeatable fashion. Potential industrial and application fields of LPM include PCB assembly, industrial sewing machines, automatic inspection, coil winder, medical uses, conveyer system, laser cut and trim systems, semiconductor wafer processing, OA instruments etc. This paper describes various design parameter of LPM such as magnetic ciucuit construction methods, phase number and tooth number per pole, permanent magnet and coil mmf, tooth geometries. And to solve the problems of existing control methods, in this paper, a new control method of the LPM is proposed throughout modern control theory.

• Korean Journal of Materials Research
• /
• v.17 no.2
• /
• pp.81-85
• /
• 2007

Embedded capacitor technology can improve electrical perfomance and reduce assembly cost compared with traditional discrete capacitor technology. To improve the capacitance density of the $Al_2O_3$ based embedded capacitor on Cu cladded fiber reinforced plastics (FR-4), the specific surface area of the $Al_2O_3$ thin films was enlarged and their surface morphologies were controlled by anodization process parameters. From I-V characteristics, it was found that breakdown voltage and leakage current were 23 V and $1{\times}10^{-6}A/cm^2$ at 3.3 V, respectively. We have also measured C-V characteristics of $Pt/Al_2O_3/Al/Ti$ structure on CU/FR4. The capacitance density was $300nF/cm^2$ and the dielectric loss was 0.04. This nano-porous $Al_2O_3$ is a good material candidate for the embedded capacitor application for electronic products.

• Journal of Institute of Control, Robotics and Systems
• /
• v.15 no.9
• /
• pp.916-921
• /
• 2009

The technology to inspect and measure an inner structure of micro parts has become an important tool in the semi-conductor industrial field with the development of automation and precision manufacturing. Especially, the inspection skill on the inside of highly integrated electronic device becomes a key role in detecting defects of a completely assembled product. X-ray inspection technology has been focused as a main method to inspect the inside structure. However, there has been insufficient research done on the customized inspection technology for the flip-chip assembly due to the interior connecting part of flip chip which connects the die and PCB electrically through balls positioned on the die. In this study, therefore, it is implemented to detect shape error of flip chip bonding without damaging chips using an x-ray inspection system. At this time, it is able to monitor the solder bump shape by introducing an edge-extracting algorithm (exponential approximation function) according to the attenuating characteristic and detect shape error compared with CAD data. Additionally, the bonding error of solder bumps is automatically detectable by acquiring numerical size information at the extracted solder bump edges.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.431-432
• /
• 2012

In the era of 20 nm scaled semiconductor volume manufacturing, Microelectronics Manufacturing Engineering Education is presented in this paper. The purpose of microelectronic engineering education is to educate engineers to work in the semiconductor industry; it is therefore should be considered even before than technology development. Three Microelectronics Manufacturing Engineering related courses are introduced, and how undergraduate students acquired hands-on experience on Microelectronics fabrication and manufacturing. Conventionally employed wire bonding was recognized as not only an additional parasitic source in high-frequency mobile applications due to the increased inductance caused from the wiring loop, but also a huddle for minimizing IC packaging footprint. To alleviate the concerns, chip bumping technologies such as flip chip bumping and pillar bumping have been suggested as promising chip assembly methods to provide high-density interconnects and lower signal propagation delay [1,2]. Aluminum as metal interconnecting material over the decades in integrated circuits (ICs) manufacturing has been rapidly replaced with copper in majority IC products. A single copper metal layer with various test patterns of lines and vias and $400{\mu}m$ by $400{\mu}m$ interconnected pads are formed. Mask M1 allows metal interconnection patterns on 4" wafers with AZ1512 positive tone photoresist, and Cu/TiN/Ti layers are wet etched in two steps. We employed WPR, a thick patternable negative photoresist, manufactured by JSR Corp., which is specifically developed as dielectric material for multi- chip packaging (MCP) and package-on-package (PoP). Spin-coating at 1,000 rpm, i-line UV exposure, and 1 hour curing at $110^{\circ}C$ allows about $25{\mu}m$ thick passivation layer before performing wafer level soldering. Conventional Si3N4 passivation between Cu and WPR layer using plasma CVD can be an optional. To practice the board level flip chip assembly, individual students draw their own fan-outs of 40 rectangle pads using Eagle CAD, a free PCB artwork EDA. Individuals then transfer the test circuitry on a blank CCFL board followed by Cu etching and solder mask processes. Negative dry film resist (DFR), Accimage$^{(R)}$, manufactured by Kolon Industries, Inc., was used for solder resist for ball grid array (BGA). We demonstrated how Microelectronics Manufacturing Engineering education has been performed by presenting brief intermediate by-product from undergraduate and graduate students. Microelectronics Manufacturing Engineering, once again, is to educating engineers to actively work in the area of semiconductor manufacturing. Through one semester senior level hands-on laboratory course, participating students will have clearer understanding on microelectronics manufacturing and realized the importance of manufacturing yield in practice.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.1 s.34
• /
• pp.9-16
• /
• 2005

This paper presents the development of new anisotropic conductive adhesives with enhanced thermal conductivity for the wide use of adhesive flip chip technology with improved reliability under high current density condition. The continuing downscaling of structural profiles and increase in inter-connection density in flip chip packaging using ACAs has given rise to reliability problem under high current density. In detail, as the bump size is reduced, the current density through bump is also increased. This increased current density also causes new failure mechanism such as interface degradation due to inter-metallic compound formation and adhesive swelling due to high current stressing, especially in high current density interconnection, in which high junction temperature enhances such failure mechanism. Therefore, it is necessary for the ACA to become thermal transfer medium to improve the lifetime of ACA flip chip joint under high current stressing condition. We developed thermally conductive ACA of 0.63 W/m$\cdot$K thermal conductivity using the formulation incorporating $5 {\mu}m$ Ni and $0.2{\mu}m$ SiC-filled epoxy-bated binder system to achieve acceptable viscosity, curing property, and other thermo-mechanical properties such as low CTE and high modulus. The current carrying capability of ACA flip chip joints was improved up to 6.7 A by use of thermally conductive ACA compared to conventional ACA. Electrical reliability of thermally conductive ACA flip chip joint under current stressing condition was also improved showing stable electrical conductivity of flip chip joints. The high current carrying capability and improved electrical reliability of thermally conductive ACA flip chip joint under current stressing test is mainly due to the effective heat dissipation by thermally conductive adhesive around Au stud bumps/ACA/PCB pads structure.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.1
• /
• pp.135-145
• /
• 2000

Manufacturing Message Specification (MMS) is designed as a communication standard protocol, ISO/IEC 9506, on factory automation for messaging between heterogeneous programmable unit controller, PLC, NC, Robot, of different vendors on the networks. MMS is also a standard protocol of OSI reference model application layer, In this paper, we show an implementation of MMS over TCP/IP using ANSI-C programming language on the unix environment, and make java classification using java native interface (NJI) with MMS library. The use of java classification provides a basic environment ot overcome a difficult programming with different MMS application programming interface (MMS-I) which requires a siklled programming technique of graphic user interface (GUI). In this paper, we implement a MMS application program of the automated assembly model for printed circuit board based on WWW which shows the operation, control and monitoring of real manufacturing device (RMD) with web browser providing users for consistent user interface.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.3
• /
• pp.371-379
• /
• 2011

Active phased array antenna structure is used for modern multi-function radars. To search targets in high clutter environment, the radar receiver needs high dynamic range performance. Though active phased array antenna structure lead to increase of SNR, the SFDR is not increased. In this paper, high SFDR receiver of X-band active phased array radar was designed and manufactured. One channel digital receiver is connected to 32 T/R modules and one PCB assembly is composed to 2 channel digital receivers with RF part, ADC part, LO distribution part and digital down conversion part. A commercial FIFO board was used for digital receiver measurement about major performance in digital output signal condition. The measured digital receiver gain and SFDR is 33 dB and more than 81 dBc each.