二氧化矽薄膜對環烯烴共聚物基板阻水氣及隔熱 特性之研究

Investigations for the moisture barrier and thermal insulation characteristic of silicon dioxide film on cyclo olefin copolymer substrate

劉彥寬(Yan-Kuan Liu)

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2007年)

摘要

塑膠基板擁有可撓曲性、比重輕及耐衝擊等優點，取代玻璃基板已成為技術發展之趨勢。但是塑膠基板阻水氣特性差、無法承受高溫製程，為發展的主要瓶頸。因此，本文藉由實驗探討塑膠基板上沉積二氧化矽薄膜後之阻水氣、隔熱及光學性質，並應用於塑膠基板的保護層。
在阻水氣量測實驗中，COC基板水氣穿透率為2.771g/day-m2，再以PECVD沉積厚度為0.25μm、0.5μm、1μm之二氧化矽薄膜後，其水氣穿透率降至0.858~0.386 g/day-m2（實驗條件為60℃、90%RH），再與玻璃基板的水氣穿透率1.7 g/day-m2相互比較，可發現沉積二氧化矽薄膜之後，其水氣穿透率降低49.5%~77.3%。
在隔熱性質量測實驗中，運用紅外線熱像儀及熱電偶量測，分別以四種不同的加熱溫度（323.15K、373.15K、408.15K、473.15K），來探討不同厚度二氧化矽薄膜對塑膠基板的隔熱效果，依數據顯示COC基板本身已有0.15%~0.40%的溫差，沉積二氧化矽薄膜之後（薄膜厚度1μm），可提升到1%的溫差（趨近於3~5K），實驗結果發現，COC基板沉積二氧化矽薄膜，可提高原本COC基板阻水氣及隔熱的效果。
在光學性質量測實驗中，二氧化矽薄膜厚度是影響其透光率的主要因素，與上述的阻水氣及隔熱效果完全相反，為了滿足塑膠基板規格需求，其透光率必須≧90%，但COC基板沉積二氧化矽薄膜之後（薄膜厚度1μm），透光率降低至88.3%，顯然已不符合需求，但薄膜厚度於0.5μm時，還保有90%的透光率。

並列摘要

Plastic substrate for flat-panel-display is flexible, light weight, and sustainable to bending deflection, and is a candidate to substitute the glass substrate. However, use of flexible plastic substrate in flat panel display manufacturing encountered two challenges: 1. moisture contents and permeations through the substrate for plastic materials are higher than glass substrate; 2. plastic substrates can’t sustain high processing temperatures. In this thesis, a silicon dioxide thin-film layer is deposited on the cyclo olefin copolymer (COC) substrate to investigate the moisture permeation, the heat conduction, and the optical characteristics experimentally.
For the moisture permeation experiments, the measured permeation of COC substrate is 2.77 g/day-m2. And after deposited by the PECVD process a silicon dioxide layer of thickness of 0.25um, 0.5um, and 1um, respectively, the measured permeation is decreased to 0.858~0.386 g/day-m2 (under 60C, 90%RH). Compared these values to the permeation of glass substrate, 1.7 g/day-m2, reduction in permeability is in 49.5%~77.3%.
For the heat conduction measurements, both of the thermocouples and IR thermography are adopted to measure the COC surface temperatures if different surface temperatures, 323.15K, 373.15K, 408.15K, and 473.15K, respectively, are applied upon the silicon dioxide surface. And effects of varied thickness of silicon dioxide film are explored. Temperature differences of COC substrate are measured to be in the range of 0.15%~0.4% for different technologies. With the deposition of silicon dioxide film (1um thickness), temperature differences is increased to 1% (about 3~5K). According to the measurements, characteristics of thermal insulation and moisture permeation of a COC substrate are enhanced by a silicon dioxide film deposition.
From the optical experiments, transmissivity is significant to thickness of silicon dioxide film, and reversed results are found in optical problem than in conduction/permeation problems. In the case of 1um thickness, transmissivity of the compoed structure is decrease to 88.3%, this is not meet the specification of 90% transmissivity for plastic substrate. But, if deposited thickness less than 0.5um, transmissivity is measured to be higher than 90%.

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