• 반도체디스플레이기술학회지
• /
• 제11권4호
• /
• pp.19-23
• /
• 2012

We report microbolometer characteristic with n-type and p-type amorphous silicon thin film. The n-type and p-type amorphous silicon thin films were made by PECVD. The electrical properties of n-type and p-type a-Si:H thin films were investigated as a function of doping gas flow rate. The doping gas used $B_2H_6/Ar$ (1:9) and $PH_3/Ar$ (1:9). In general, the conductivity of doping a-Si:H thin films increased as doping gas increase but the conductivity of a-Si:H thin films decreased as the doping gas increase because doping gas concentration increase led to dilution gas (Ar) increase as the same time. We fabricated an amorphous silicon microbolometer using surface micromachining technology. The fabricated microbolometer had a negative TCR of 2.3%. The p-type microbolometer had responsivity of $5{\times}10^4V/W$ and high detectivity of $3{\times}10^8cm(Hz)^{1/2}/W$. The p-type microbolometer had more detectivity than n-type for less noise value.

• 한국정밀공학회지
• /
• 제31권3호
• /
• pp.269-275
• /
• 2014

Conventional machining technologies such as a milling process have limitations in accuracy to fabricate microstructures. Deep X-ray lithography using the synchrotron radiation is a promising micromachining process with an excellent accuracy, whereas there are difficulties in the fabrication of multi-layered structures. Therefore, it is mainly used for fabricating simple mono-layered microstructures with a high aspect ratio. In this study, a novel technology for fabricating multi-layered microstructures is proposed by combining two processes. In advance, an X-ray resist material is cut and machined into various shapes and heights by the micro milling process. Subsequent X-ray irradiation process facilitates the fabrication of multi-layered microstructures. The proposed technology can overcome the limitation of the pattern accuracy in conventional milling process and the difficulty of the multi-layered machining in x-ray process. The usefulness of the proposed technology is demonstrated in this study by applying the technique in the realization of various multi-layered microstructures.

• Transactions on Electrical and Electronic Materials
• /
• 제7권4호
• /
• pp.157-162
• /
• 2006

Chemical-mechanical polishing (CMP), one of the dominant technology for ULSI planarization, is used to flatten the micro electro-mechanical systems (MEMS) structures. The objective of this paper is to achieve good planarization of the deposited film and to improve deposition efficiency of subsequent layer structures by using surface-micromachining process in MEMS technology. Planarization characteristic of poly-Si film deposited on thin oxide layer with MEMS structures is evaluated with different slurries. Patterns used for this research have shapes of square, density, line, hole, pillar, and micro engine part. Advantages of CMP process for MEMS structures are observed respectively by using the test patterns with structures larger than 1 urn line width. Preliminary tests for material selectivity of poly-Si and oxide are conducted with two types of silica slurries: $ILD1300^{TM}\;and\;Nalco2371^{TM}$. And then, the experiments were conducted based on the pretest. A selectivity and pH adjustment of slurry affected largely step heights of MEMS structures. These results would be anticipated as an important bridge stone to manufacture MEMS CMP slurry.

• 센서학회지
• /
• 제28권2호
• /
• pp.127-132
• /
• 2019

In this study, the fabrication of through-silicon vias (TSVs) filled with SWNTs/Sn by utilizing surface/bulk micromachining and MEMS technologies is proposed. Tin (Sn) and single-walled nanotube (SWNT) powders are used as TSV interconnector materials in the development of a novel TSV at low temperature. The measured resistance of a TSV filled with SWNT/Sn powder is considerably reduced by increasing the fraction of Sn and is lower than that of a TSV filled with only Sn. This is because of a decrease in the surface scattering of electrons along with an increase in the grain size of sintered SWNTs/Sn. The proposed method is conducted at low temperatures (< $400^{\circ}C$) due to the low melting temperature of Sn; hence, the proposed TSVs filled with SWNTs/Sn can be utilized in CMOS based applications.

• 센서학회지
• /
• 제8권5호
• /
• pp.414-420
• /
• 1999

희생층을 제거하는 기술은 표면 마이크로머시닝 공정의 핵심기술중 하나이다. 그러나 희생층을 제거하는데 널리 쓰이는 BHF 용액을 포함한 HF 수용액은 희생층 제거시 금속층으로 쓰이는 알루미늄도 같이 식각하는 것으로 알려져 있다. 기존의 문헌에서 $NH_4F$:HF:glycerine=4:1:2의 비를 갖는 혼합 용액이 알루미늄과 PSG 간의 식각 선택비가 최적조건으로 제시되었지만 이 희생층 식각액 또한 상당한 알루미능 식각률을 가지고 있다. 본 논문에서는 HF, $NH_4F$, glycerine의 농도를 광범위하게 변화시켜 희생층 제거에 필요한 최적 혼합비를 개발하였으며 그 결과 $NH_4F$:HF:glycerine=2:1:4의 혼합비에서 약 7,700정도의 PSG와 Al의 식각 선택비를 가져 기존의 최적 식각 선택비보다 차수가 약 6배정도 향상된 희생층 식각액을 얻을 수 있었다. 이 조건에서 PSG의 식각률은 희생층 제거시 충분히 빠른 값인 약 $2.1\;{\mu}m/min$을 나타내었다. 이러한 개발된 희생층 식각액은 표면 마이크로머시닝 공정에서 알루미늄 금속 공정의 추가를 용이하게 한다.

• Transactions on Electrical and Electronic Materials
• /
• 제15권2호
• /
• pp.91-95
• /
• 2014

This paper presents the structure and process technology of simple and low-cost wafer-level packaging (WLP) for thin film radio frequency (RF) devices. Low-cost practical micromachining processes were proposed as an alternative to high-cost processes, such as silicon deep reactive ion etching (DRIE) or electro-plating, in order to reduce the fabrication cost. Gold (Au)/Tin (Sn) alloy was utilized as the solder material for bonding and hermetic sealing. The small size fabricated WLP of $1.04{\times}1.04{\times}0.4mm^3$ had an average shear strength of 10.425 $kg/mm^2$, and the leakage rate of all chips was lower than $1.2{\times}10^{-5}$ atm.cc/sec. These results met Military Standards 883F (MIL-STD-883F). As the newly proposed WLP structure is simple, and its process technology is inexpensive, the fabricated WLP is a good candidate for thin film type RF devices.

• 한국소음진동공학회논문집
• /
• 제16권12호
• /
• pp.1272-1278
• /
• 2006

This paper presents a novel MEMS condenser microphone with rigid backplate to enhance acoustic characteristics. The MEMS condenser microphone consists of membrane and backplate chips which are bonded together by gold-tin(Au/Sn) eutectic solder bonding. The membrane chip has $2.5mm{\times}2.5mm$, 0.5${\mu}m$ thick low stress silicon nitride membrane, $2mm{\times}2mm$ Au/Ni/Cr membrane electrode, and 3${\mu}m$ thick Au/Sn layer. The backplate chip has $2mm{\times}2mm$, 150${\mu}m$ thick single crystal silicon rigid backplate, $1.8mm{\times}1.8mm$ backplate electrode, and air gap, which is fabricated by bulk micromachining and silicon deep reactive ion etching. Slots and $50{\sim}60{\mu}m$ radius circular acoustic holes to reduce air damping are also formed in the backplate chip. The fabricated microphone sensitivity is 39.8 ${\mu}V/Pa$(-88 dB re. 1 V/Pa) at 1 kHz and 28 V polarization voltage. The microphone shows flat frequency response within 1 dB between 20 Hz and 5 kHz.

• 한국정보통신설비학회:학술대회논문집
• /
• 한국정보통신설비학회 2004년도 하계학술대회
• /
• pp.11-14
• /
• 2004

In this paper, a novel tunable bandpass filter using tunable series inductors and MEMS switches for wireless LAN applications was proposed. The proposed tunable filter was fabricated using a micromachining technology and performances of the fabricated filter were estimated. The filter consists of spiral inductors, MIM capacitors and direct-contact type MEMS switches, and its frequency tunability is achieved by changing the inductance that is induced by ON/OFF actuations of the MEMS switches. The actuation voltage of the MEMS switches was 58 V, and the measured center frequencies were 2.55 GHz and 5.1 GHz, respectively. The passband insertion loss and 3-dB bandwidth were 4.2 dB and 22.5 % at 2.55 GHz, and 5.2 dB and 23.5 % at 5.1 GHz, respectively.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.620-623
• /
• 2003

The material processing by using ultrashort pulse laser, in recently, is actively applying into the micro machining and nano-machining technology since ultrashort pulse has so faster than the time which the electrons energy absorbing photon energy is transmitted to surrounding lattice-phonon that it has many advantages in point of machining. The micro machining of metallic thin film on the plain glass is widely used in the fields such as mask repairing for semiconductor, fabrication of photonic crystal, MEMS devices and data storage devices. Therefore, it is important to secure the machining technology of the sub-micron size. In this research, we set up the machining system by using ultrashort pulse laser and conduct on the Cr 200nm thin film ablation experiments of spot and line with the variables such as energy, pulse number, speed, and so on. And we observed the characteristics of surrounding heat-affected zone and by-products appeared in critical energy density and higher energy density through SEM, and also examined the machining features between in He gas atmosphere which make pulse change minimized by nonlinear effect and in the air. Finally, the pit size of 0.8${\mu}{\textrm}{m}$ diameter and the line width of 1${\mu}{\textrm}{m}$ could be obtained.

• 센서학회지
• /
• 제1권1호
• /
• pp.35-41
• /
• 1992

기체와 액체의 유숙을 측정하기 위한 반도체 기술을 이용한 소형의 정온도형 유속센서가 제작되었다. 유속센서는 유속에 영향을 받는 대류 열전달만을 검출하도록 설계되었고, 다른 종류의 열전달과 간섭효과는 기준센서의 사용으로 상쇄되도록 하였다. 원리는 유동에 의한 센서 양단전류의 변화로 유속을 측정하는 것이다. 이 유속센서의 실험은 수돗물로 가는 관(지름 8mm)을 사용하여 수행되었다. 그 결과 센서의 소비전력과 유속의 제곱근 사이의 관계는 유속이 0-200cm/sec 범위에서 거의 선형으로 나타났다.