• 대한기계학회논문집A
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• 제32권5호
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• pp.419-423
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• 2008

A new polymer replication technology using ultrasonic vibration is proposed and demonstrated. A commercial ultrasonic welder has been used in this experiment. Two different types of nickel molds have been fabricated: pillar type and pore type microstructures. Polymethyl methacrlylate (PMMA) has been used as the replication material and the optimal molding time was 2 sec and 2.5 sec for pillar-type and pore-type micromolds, respectively. Compared with the conventional polymer micromolding techniques, the proposed ultrasonic micromolding technique has the shortest processing time. In addition, only contact area between micromold and polymer substrate is melted so that the thermal shrinkage can be minimized. The fabricated PMMA microstructures have been very accurately replicated without vacuum. The proposed ultrasonic molding technique is a good alternative for high volume production.

• 소성∙가공
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• 제22권1호
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• pp.36-41
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• 2013

The present study examines the micro-pattern replication on a plastic film using ultrasonic imprinting. Ultrasonic imprinting uses ultrasonic waves to generate repetitive microscale deformation in the polymer film. The resulting deformation heat on the surface of the film causes the surface region to soften sufficiently so that a replication of the micro-pattern can be obtained. To successfully replicate the micro-pattern on a large area of polymer film, a high replication ratio is needed as well as good uniformity over the entire region. In this study, a horn design is investigated by finite element analysis and is optimized through a response surface analysis. In the ultrasonic imprinting experiments, the response surface method was also used to determine the optimal processing conditions for better replication characteristics.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.368-368
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• 2006

Micro-molded parts can be defined as parts with microgram weight, parts with micro-structured surface, and parts with micro-precision. In this study, various micro-scale molded parts for various polymers were produced by using a precision micro-molding machine. Molded parts with nano-structure surface were also produced to analyze the effect of molding conditions on replication of surface pattern and higher-order structure development of molded parts. Replication of molded parts was influenced by material properties, molding conditions and size of surface pattern. Higher-order structure of molded parts was investigated by using polarized microscope. Skin-shear-core regions inside the molded parts were observed and shear region affected to surface replication.

• 한국생산제조학회지
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• 제18권3호
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• pp.307-314
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• 2009

Large area micro pattern replication has promising application potential in many areas. Rolling imprint process has been demonstrated as one of the most competitive processes for such micro pattern replication, because it has advantages in low cost, high throughput and high efficiency. In this paper, we developed a prototype of roll-to-flat(R2F) thermal imprint system for large area micro pattern replication process, which is one of the key processes in the fabrication of flexible displays. Experimental tests were conducted to evaluate the feasibility of system and the parameters' effect on the process, such as flat mold temperature, loading pressure and rolling speed. 100mm $\times$ 100mm stainless steel flat mold and commercially available polycarbonate sheets were used for the tests. The experimental results showed that the developed R2F system is suitable for fabrication of various micro devices with micro pattern over large area.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
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• pp.7-11
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• 2003

집적회로에서 발생되는 열은 회로의 불안정한 동작을 야기하여 시스템의 기능을 저하시키므로 동작중인 집적회로를 일정온도 이하로 유지 할 수 있는 장치가 요구된다. 현재 사용되는 방열 시스템은 대부분이 크기가 큰 공냉식이며 Heat sink의 크기로 인해 수냉식의 방열 시스템 역시 그 크기가 칩의 크기보다 매우 크다. 본 논문에서는 드라이 필름 레지스터를 사용하여 짧은 제작 기간과 적은 비용으로 Master를 제작하였다. 이 Master를 사용한 Replication 공정을 이용하여 칩의 패키지내에 삽입될 수 있는 Polymer Heat Exchanger를 제작하였다.

• 대한기계학회논문집A
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• 제38권1호
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• pp.51-57
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• 2014

초음파 임프린팅은 열가소성 고분자 기판에 미세패턴을 복제할 수 있는 공정으로 타 성형방법에 비해 에너지소모가 적고 성형시간이 단축되는 장점이 있다. 초음파 임프린팅 공정에서는 고분자 기판의 표면에 초음파 진동에너지를 인가하여 소재간의 마찰열과 미세하게 반복되는 변형에너지의 축적을 통해 고분자 표면을 국부적으로 가소화시켜 미세패턴이 전사된다. 본 연구에서는 초음파 임프린팅에서 금형 온도가 미세패턴의 전사성에 미치는 영향을 분석하였다. 이를 위해 금형온도를 변화시켜가며 임프린팅을 수행하여 미세패턴 성형 영역에서의 온도변화를 관찰하였고, 상기 온도변화를 고려하여 미세패턴의 충진과정을 전산모사를 통해 고찰하였다. 또한 금형온도 변화에 따른 패턴의 전사율 및 전사균일도를 측정하여 비교하였다. 상기 결과를 통해 금형온도를 높일수록 초음파 임프린팅시 미세패턴의 전사특성이 향상됨을 확인할 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.940-944
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• 2003

With the increasing demand for plastic micro components, micro-/nano-molding using the mother stamper has received much attention. If the replication temperature is too high, the adhesion between the stamper and the polymer melt may deteriorate the surface quality of the replicated part, excessively wearing down the stamper. In this paper, an experimental method analyzes the temperature dependency of the anti-adhesion property between the actual stamper with patterns of sub-micrometer and the polymer melt. As a practical example, a correlation between the contact angle of the stamper and the surface quality of the molded substrates as a function of the replication temperature, respectively, was obtained quantitatively.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.179-180
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• 2007

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.42-43
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• 2000

Aspheric optical elements can provide an advantage in the design of optical system that require high performance and small size. The main disadvantage of high volume production of aspheric optical elements is very high cost. In this paper, we suggest new technology of high volume production process using replication process. The replication is a thin film of UV cured resin on a solid substrate blank(polymer substrate) with aspheric surface.

• 한국세라믹학회지
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• 제40권6호
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• pp.519-524
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• 2003

Porous carbon with high surface area and pore volume was prepared by a reverse replication process and its toluene equilibrium adsorption behavior was investigated. The preparation process of the porous carbon was composed of fellowing sub-processes in series: synthesis and template preparation of silica gel, impregnation and polymerization of DVB monomer in silica template, carbonization of DVB polymer in a silica-polymer composite, and HF-assisted selective etching of silica in carbon-silica composite. The prepared porous carbon was nano porous and had ultrahigh specific surface area (2007 ㎡/g) and large pore volume (3.07 ㎤/g). The nanoporous carbon showed rapid toluene adsorption rate and good toluene adsorption capacity, compared with a commercial Y-type zeolite. In the present study, a reverse replication process to prepare nanoporous carbons will be introduced and its application potential as a gas adsorbent will be discussed.