Sıcak Kabartma Sırasında Kullanılan Kalıp Malzemelerinin Döngüsel Olefin Polimer (COP) Alttaşta Mikrofabrikasyonda Yapıların Doğruluğuna Etkisi

Yıl 2024, Cilt: 24 Sayı: 2, 457 - 464, 29.04.2024

Ahmet Can Erten

https://doi.org/10.35414/akufemubid.1345104

Öz

Araştırmadan pazara geçiş sırasında, termoplastik yüzeylerde mikroakışkan cihazların imalatı kaçınılmazdır. Daha yüksek üretim hacimleri için tipik olarak kullanılan pahalı enjeksiyon kalıplama işlemine geçmeden önce birkaç yüz ürün gibi küçük hacimli üretim süreçleri için, sıcak kabartma tipik yöntemdir. Bu çalışmada, sıcak kabartma sırasında kullanılan kalıp malzemelerinin döngüsel olefin polimer (COP) substratta mikrofabrikasyonda üretim sonuçları üzerindeki etkisini araştırdık. Spesifik olarak, basit bir akış odaklamalı mikroakışkan cihazı tasarladık ve bu tasarımı kullanarak silisyum, alüminyum dolgulu epoksi ve alüminyum alttaşlar kullanarak üç farklı kalıp ürettik. Bu üç farklı kalıp malzemesini COP substrat ile otomatik tezgâh üstü Carver sıcak preste kullanarak sıcak kabartma deneyleri yaptık. Son olarak, sıcak kabartmalı alt tabakaları optik mikroskop ve taramalı elektron mikroskop ile karakterize ettik. Üretim sonuçları, kalıp malzemesinin üretim sonuçları üzerinde büyük bir rol oynadığını göstermektedir. Kullanılan kalıp malzemeleri arasında silisyum alttaş, kalıptan çıkarma sonrasındaki kusurlara göre en kötü performansı göstermiştir. Epoksi ve alüminyum kalıplar, çoğunlukla termal genleşme katsayılarına (CTE) atfedilebilen alt tabakadaki mikro fabrikasyon özellik kusurları açısından benzerdi. Termoplastiğe daha yakın bir CTE'ye sahip bir kalıp malzemesi, çok daha iyi özellik doğruluğu ile sonuçlanacaktır.

Anahtar Kelimeler

Sıcak Kabartma, COP, Kalıp, Termoplastik, Döngüsel Olefin Polimer

Effect of Mold Materials Used During Hot Embossing on Feature Fidelity for Microfabrication in Cyclic Olefin Polymer (COP) Substrate

Öz

During the transition from research to market, the fabrication of microfluidic devices in thermoplastic substrates is inevitable. For short production runs of several hundred products, hot embossing is the typical method before moving on to a typically more expensive injection molding process for higher production volumes. In this work, we investigated the effect of mold material used during hot embossing on feature fidelity for microfabrication in cyclic olefin polymer (COP) substrate. Specifically, we designed a simple flow-focusing microfluidic device and fabricated three different molds using silicon wafer by deep reactive ion etching (DRIE), aluminum filled high temperature epoxy by soft lithography and aluminum by CNC milling. We performed hot embossing experiments with 2mm thick COP substrates and these three different molds using automatic bench top Carver hot press. Finally, we characterized the hot embossed substrates by optical and scanning electron microscopy. Fabrication results demonstrate that the mold material plays a big role in feature fidelity. Among the mold materials used, silicon substrate performed the worst based on defects after demolding. Epoxy and aluminum molds were similar in terms of microfabricated feature defects in the substrate which could be mostly attributed to their coefficient of thermal expansion (CTE). A mold material with a CTE closer to the thermoplastic will result in much better feature fidelity.

Anahtar Kelimeler

Hot Embossing, COP, Mold, Thermoplastic, Cyclic Olefin Polymer

Kaynakça

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