高頻下介電常數與消散因子與聚醯亞胺分子結構之關係

聚醯亞胺因具有高熱穩定性，高耐化學性和出色的機械性質，在電子工業有廣泛之應用。隨著無線和移動通信的迅速發展，為了滿足物聯網（IoT）、汽車設備、數位醫療和大數據的需求，工作頻率已增加到GHz頻段。為了提高信號傳輸速率、信號完整性並防止由於介電損耗引起的信號失真，急迫需要在高頻下具有低介電常數（Dk）和低耗散因子（Df）的材料。然而，對於設計同時具有低介電常數（Dk）和低耗散因子（Df）的聚醯亞胺並沒有明確的準則，但這對於新興的第五代行動通信技術(5G)非常重要。因此，釐清低介電常數（Dk）和低耗散因子（Df）聚醯亞胺的分子結構設計概念是一個有趣且具有挑戰性的問題。在第2章中，我們使用四種二酐:PMDA、ODPA、6FDA、BPADA和四種二胺ODA、6FPDA、BAPP、BAPHF製備16種聚醯亞胺，透過分子結構設計實現低介電常數（Dk）和低耗散因子（Df）。實驗結果發現，Dk與氟含量以及Df與醯亞胺基團含量之間具有高度相關性，相關係數超過0.95。上述結果可以用克勞修斯-莫索蒂方程式和電場下分子之間的極化振盪效應來解釋。此外，在各種相對濕度（RH）下的吸水率和介電性能被用來評估介電性能的穩定性。具有低醯亞胺基團含量的聚醯亞胺在0至100％RH條件下表現出穩定的介電性能。在第3章中，為了找出Dk和Df的通用相關性，除了第2章所合成的16種聚醯亞胺，我們使用5種二酐BPDA、BPADA、TAHQ、BTDA、DSDA和12種二胺ODA、BAPP、DABA、PABA、APAB、DABP、ASD、DTDA、BAPS、C3NH2、C6NH2、C12NH2 製備了另外20種聚醯亞胺，這36種聚醯亞胺具有不同官能基團，包括醚、氟、醯胺、酯、酮、硫、碸和脂肪族鏈。實驗結果發現，介電常數（Dk）與體積分之極化度(P/V)和耗散因子(Df)與體積分之偶極矩(μFr/V)之間具有高度相關性。此外，我們建立了一種可以通過加成基團貢獻和Fröhlich方程式估算聚醯亞胺Df值的方法。本研究為高頻下低介電常數與低消散因子聚醯亞胺分子結構設計提供了準則，並能應用在第五代行動通信技術(5G)高頻應用上。

關鍵字

聚醯亞胺；高頻應用；低介電常數；低消散因子

並列摘要

Polyimide (PI) has been extensively studied in electronic industry due to its’ high thermal stability, high chemical resistance, and excellent mechanical properties. With the rapid growth of wireless and mobile communication, the operation frequency has increased to GHz bands in order to meet the requirement of internet of things (IoT), car device, digital health and big data. To improve a signal transmission rate, signal integrity and prevent signal distortion arising from the dielectric loss, materials with low Dk and Df values at a high-frequency are highly demanded. However, there is no clear guideline on designing PIs with both low Dk and low Df , which is very important for the emerging Fifth-Generation Mobile Communications Technology. Therefore, it is an interesting and challenging issue to clear the design concept of low Dk and Df PIs. In chapter 2, we explored the molecular structure design polyimides (PIs) to achieve a low dielectric constant (Dk) and a low dissipation factor (Df) using sixteen PIs prepared from four kinds of dianhydrides, PMDA, ODPA, 6FDA, BPADA and four diamines of ODA, 6FPDA, BAPP and BAPHF. The experimental results showed that the highly correlated relationship between the Dk and fluorine content and the Df to the imide group content, with a correlation coefficient over 0.95. This above result can be explained by the Clausius-Mossotti equation and the effect of polarization oscillation among the molecules under the electric field. Furthermore, water absorption and dielectric properties at various relative humidity (RH) were used to evaluate the stability of dielectric properties. The PIs with the low imide group content exhibited stable dielectric properties under 0 to 100% RH condition. In chapter 3, the other twenty PIs were prepared from five dianhydrides BPDA, BPADA, TAHQ, BTDA, DSDA and twelve diamines ODA, BAPP, DABA, PABA, APAB, DABP, ASD, DTDA, BAPS, C3NH2, C6NH2, C12NH2. Including chapter 2, thirty-six kinds of PIs with different functional group including ether, fluorine, amide, ester, ketone, sulfide, sulfone and aliphatic chain were synthesis in order to figure out the universal correlation of Dk and Df. The high correlated relationship between dielectric constant (Dk) to the polarization divided by volume (P/V) and the dissipation factor (Df) to the dipole moment divided by volume (μFr/V) are found. Furthermore, a method which can estimate the Df value of the PI by the additive group contribution and the Fröhlich equation is established. This work provides a guideline for using the molecular structure design of PIs for high frequency applications on Fifth-Generation Mobile Communications Technology.