以影像顯示產業廢棄物製成低溫共燒陶瓷之資材化研究

本研究利用薄膜電晶體液晶顯示器(Thin-film transistor liquid-crystal display, TFT-LCD)廢素玻璃，其SiO2純度超過60 wt%而具備優良介電性質的特性，將其改質進行資材化再利用製成低溫共燒陶瓷(Low-Temperature Co-fired Ceramics, LTCC)。LTCC的原料是可在小於900 oC的溫度，與低溶點、高導電性的電極材料進行共燒，產出體積小而符合電子產品輕薄短小的設計原則。然而，TFT-LCD廢素玻璃粉末的燒結溫度在900 oC以上，故有改質降低其燒結溫度的必要性。再者，為使電子設備具備快速的訊號傳輸速度，其介電常數(Dielectric constant)必須小於9；為降低電子產品實際應用時之能量損失，其品質因子須大於300，故本研究以TFT-LCD廢素玻璃添加CaCO3、CaF2與CaB2O4等鈣系調質劑進行調質，除利用玻璃修飾劑(鈣離子)降低其燒結溫度外，並使配比成份與商用之CAS(CaO-Al2O3- SiO2)系與CBS (CaO-B2O3-SiO2)系LTCC相近以優化其介電性質，期其燒結溫度及介電性質符合LTCC應用規範之要求。考量調配之混和原料粉末是否經過熔融玻璃化程序將影響其燒結特性與介電性質，本研究採用「混燒」(混合原料粉末直接燒結)與「玻璃陶瓷」(混合原料粉末先熔融玻璃化後再進行燒結)兩種製程進行資材化研究，並探討製程差異的影響。研究成果顯示，不同調質劑種類降低TFT-LCD燒結溫度之機制不同，故合適之製程亦不相同。添加CaF2與CaCO3之CAS系統，以「破壞矽氧結構性」機制來降低燒結溫度，適合採玻璃陶瓷製程；添加CaB2O4之CBS系統，以「產生液相輔助燒結」機制來降低燒結溫度，適合採混燒製程。優化介電性質部分，密度與孔隙率是介電常數的主要影響因子，CAS系配比因有較高之緻密化程度，故其介電常數比CBS系配比高。當CaCO3與CaB2O4的添加量上升會使品質因子下降；隨CaF2之添加量上升則因F離子存在而使品質因子增加，可改善其介電性質。製程差異對介電性質的影響在於採玻璃陶瓷製程產出材料之緻密化程度較高而介電常數較高，且因成分均勻、相較單純缺陷較少，故品質因子較高。本研究成功將TFT-LCD玻璃高於900 oC的燒結溫度，藉由添加CaCO3、CaF2與CaB2O4等調質劑降至900 oC以下，並降低其介電損失而改善其介電性質，使其燒結溫度與介電性質符合商用LTCC的應用規範。

關鍵字

影像顯示產業廢棄物；低溫共燒陶瓷；介電性質

並列摘要

A low-temperature co-fired ceramics (LTCC) was prepared from thin-film transistor liquid-crystal display (TFT-LCD) waste glasses using thermal treatments including glass-ceramic process and sintering process. The excellent dielectric properties of TFT-LCD waste glasses are original from it highly SiO2 content. However, the sintering temperature of TFT-LCD waste glass powder is higher than LTCC (900 oC). Therefore, TFT-LCD waste glasses need an adjustment in composition to lower its sintering temperature. Moreover, a dielectric constant of lower than 9 and quality factor higher than 300 were also required to meet the cretira of LTCC. The composition of TFT-LCD waste glasses is similar with CaO–Al2O3–SiO2 (CAS) and CaO–B2O3–SiO2 (CBS) system. Both systems are generally used in the production of commercial LTCC.With the regard, CaCO3, CaF2 and B2CaO4 were added as adjusting agents to TFT-LCD waste glass to produce LTCC in CAS and CBS system. The results indicated that the sintering temperature and dielectric properties of LTCC produced from composition-adjusted TFT-LCD waste glass were meet the creteria of commercial LTCC. In glass-ceramic process, the Ca ions weaken the net glass structure and lower the sintering temperature by acting as modifyin agent. In sintering process, the adding of B2CaO4 increased the quantities of liquid phases, which enhanced liquid sintering and the sintering temperature was reduced. The dielectric constant of LTCC depends mainly on its density and porosity. The dielectric constant of investigated CAS system is higher than CBS system due to the densification degree of CAS system is much higher. A reduction of quality factor can be observed with the increasing CaCO3 and B2CaO4 content. On the contrary, quality factor increased with the increasing addition of CaF2. This phenomen can be attributed to the substitution of oxygen ions by fluoride ions in the Si-O structure of glass. A fine, homogenous microstructure in LTCC can be achieved via glass-cermaic process. Then, minor defeat in microstructure makes a higher quality factor of LTCC. This study successful produced LTCC from composition-adjusted TFT-LCD waste glass, and the thermal and dielectric properties meet the creteria of commercial LTCC.

並列關鍵字

TFT-LCD Waste Glass ； LTCC ； Dielectric properties

參考文獻

陳炫妤，李公哲，TFT-LCD玻璃添加調質劑形成MAS系玻璃陶瓷之研究，國立台灣大學環境工程學研究所碩士論文，2011

林東宏、李公哲，TFT-LCD玻璃混合轉爐石爐渣熱處理資材化製成絕緣玻璃陶瓷之研究，國立台灣大學環境工程學研究所碩士論文，2010

范振軒，李公哲，TFT-LCD玻璃/氟化鈣污泥熱處理資材化為絕緣玻璃陶瓷之研究，國立台灣大學環境工程學研究所碩士論文，2010

黃智揚，李公哲，TFT-LCD玻璃混合轉爐石資材化燒製輕質骨材之發泡機制研究，國立台灣大學環境工程學研究所碩士論文，2013

Chen, Y. C., Chen, K. C. and Chen, K. H., Effect of B2O3 additions and sintering temperature on the microwave dielectric properties of 0.7La(Mg0.5Sn0.5)O3 -0.3(Sr0.8Ca0.2)3Ti2O7 ceramics, Ferroelectrics Letters, vol. 38, pp. 59-68, 2011

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以影像顯示產業廢棄物製成低溫共燒陶瓷之資材化研究

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