• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1231-1235
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• 2004

The needs of micro scale thermal detecting technique are increasing in biology and chemical industry. For example, Thermal finger print, Micro PCR(polymer chain reaction), ${\mu}TAS$ and so on. To satisfy these needs, we developed a DTSA(Diode Temperature Sensor Array) for detecting and controlling the temperature on small surface. The DTSA is fabricated by using VLSI technique. It consists of 32 ${\times}$ 32 array of diodes (1,024 diodes) for temperature detection and 8 heaters for temperature control on a 8mm ${\times}$ 8mm surface area. The working principle of temperature detection is that the forward voltage drop across a silicon diode is approximately proportional to the inverse of the absolute temperature of diode. And eight heaters ($1K{\Omega}$) made of poly-silicon are added onto a silicon wafer and controlled individually to maintain a uniform temperature distribution across the DTSA. Flip chip packaging used for easy connection of the DTSA. The circuitry for scanning and controlling DTSA are also developed

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2449-2452
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• 2007

Hot spots on thin wafers of IC packages are becoming important issues in thermal and electrical engineering fields. To investigate these hot spots, we developed a Diode Temperature Sensor Array (DTSA) that consists of an array of 32 ${\times}$32 diodes (1,024 diodes) in a 8 mm ${\times}$ 8 mm surface area. To know specifically the hot spot temperature which is affected by the chip thickness and a generated power, we made the DTSA chips, which have 21.5 ${\mu}m$, 31 ${\mu}m$, 42 ${\mu}m$, 100 ${\mu}m$, 200 ${\mu}m$, and 400 ${\mu}m$ thickness using the CMP process. And we conducted the experiment using various heater power conditions (0.2 W, 0.3 W, 0.4 W, 0.5 W). In order to validate experimental results, we performed a numerical simulation. Errors between experimental results and numerical data are less than 4%. Finally, we proposed a correlation for the hot spot temperature as a function of the generated power and the wafer thickness based on the results of the experiment. This correlation can give an easy estimate of the hot spot temperature for flip chip packaging when the wafer thickness and the generated power are given.

• Korean Journal of Materials Research
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• v.28 no.1
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• pp.32-37
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• 2018

We report on the efficient detection of NO gas by an all-oxide semiconductor p-n heterojunction diode structure comprised of n-type zinc oxide (ZnO) nanorods embedded in p-type copper oxide (CuO) thin film. The CuO thin film/ZnO nanorod heterostructure was fabricated by directly sputtering CuO thin film onto a vertically aligned ZnO nanorod array synthesized via a hydrothemal method. The transport behavior and NO gas sensing properties of the fabricated CuO thin film/ZnO nanorod heterostructure were charcterized and revealed that the oxide semiconductor heterojunction exhibited a definite rectifying diode-like behavior at various temperatures ranging from room temperature to $250^{\circ}C$. The NO gas sensing experiment indicated that the CuO thin film/ZnO nanorod heterostructure had a good sensing performance for the efficient detection of NO gas in the range of 2-14 ppm under the conditions of an applied bias of 2 V and a comparatively low operating temperature of $150^{\circ}C$. The NO gas sensing process in the CuO/ZnO p-n heterostructure is discussed in terms of the electronic band structure.