無電鍍銀微粒應用於導電膠及烷基硫醇對 導電度效應之研究

Abstract

摘要 本實驗分成二個部分討論：第一部分為製備導電粒子的研究，第二部分為製備導電膠的研究。藉由粒徑分析儀與SEM觀察顆粒尺寸與顆粒形貌；而藉由XRD及ICP觀察無電鍍銀後，銀是否有鍍著在微粒表面與銀鍍上去的量；而藉由ESCA觀察鍍銀微粒經硫醇修飾後，硫醇是否會長在其表面上。 實驗結果發現在製備導電粒子實驗方面，先將平均粒徑為0.804 μm的扁平雪片狀銅粉Cu浸鍍銀，也將平均粒徑為0.982 μm的扁平雪片狀石墨粉GS-75與平均粒徑為4.292 μm的扁平雪片狀石墨粉GP-44無電鍍銀；由XRD觀察無電鍍銀後的微粒可知鍍銀銅粉Cu/Ag表面產生Ag與阻擋電性導通的CuO；而鍍銀石墨粉GS-75/Ag與GP-44/Ag表面皆產生Ag與幫助電性導通的Ag2O。由ICP觀察無電鍍銀的最佳時間可知銅浸鍍銀的最佳時間為30秒，30秒過後氧化還原反應將停止；而石墨粉無電鍍銀的最佳時間為3分鐘，3分鐘過後因為石墨粉表面的活化層Pd已被覆蓋，所以氧化還原反應會變慢，但不會停止，而且比表面積較大的小顆粒石墨粉GS-75吸附銀的量會比大顆粒石墨粉GP-44吸附銀的量較多。由ECSA觀察硫醇修飾鍍銀微粒可知硫醇是否有長到鍍銀微粒上，結果證明三種鍍銀微粒 Cu/Ag、GS-75/Ag、GP-44/Ag在浸泡硫醇10分鐘後，直鏈烷基硫醇皆有長到其表面上。 在製備導電膠實驗方面，發現微粒在浸鍍銀或無電鍍銀之後，電阻係數ρ必定會下降；而且微粒在加入硫醇當分散劑之後，電阻係數ρ也必定會下降，故三種微粒Cu,GS-75,GP-44在鍍銀且加入分散劑硫醇之後，電阻係數ρ皆會比原本不鍍銀且不加入分散劑硫醇下降約一個order，而導電粒子與硫醇的最佳比例為1：0.4，而且碳鏈長度越短的硫醇，其電阻係數ρ會越低。GS-75/Ag加入0.4g C4H9SH的硫醇修飾其表面之後，其電阻係數ρ為0.014 ohm-cm，此值為本論文所作出來的最佳且最低的電阻係數值。

Abstract The thesis was divided into two parts. The first part of study was preparing conductive particles. The second part of study was preparing electrically conductive adhesives(ECAs). In the experiments, we observed particle size and surface morphology by particle size instrument and SEM. We also analyzed if silver was electroless plated on particles surface and plated weight by XRD and ICP. We also analyzed if alkyl thiol compound was deposited on particles surface by ESCA. In the study of preparing conductive particles, we take the 0.804 μm flake copper to immerse silver, and we also take the 0.982 μm flake graphite(GS-75) and the 4.292 μm flake graphite(GP-44) to plate silver electroless. We can find there was Ag and CuO on Cu/Ag particle surface by XRD, and there was Ag and Ag2O on GS-75/Ag and GP-44/Ag particles surface by XRD. We also find the best plated time of copper was 30 seconds by ICP, and the reaction stopped after 30 seconds. The best plated time of graphite was 3 minutes by ICP. The reaction rate became slow after 3 minutes because the catalytic layer (Pd layer) had been covered. In the same time, small particle graphite (GS-75) electroless plated more silver weight than big particle graphite (GP-44),because the specific surface area of small particle graphite (GS-75) was bigger. We can find alkyl thiol compound deposited on Cu/Ag、GS-75/Ag、GP-44/Ag after immersing 10 minutes alkyl thiol compound by ESCA. In the study of preparing electrically conductive adhesives, we can find resistivity ρ must decline after immersing silver or electroless plating silver. We also find resistivity ρ must decline after adding alkyl thiol compound, so resistivity ρ of ECAs of three particles Cu 、GS-75、 GP-44 decline about one order after plating silver and adding alkyl thiol compound. The best ratio between conductive particles and alkyl thiol compound was 1：0.4, and resistivity ρ of ECAs was lower for the shorter carbon chain of alkyl thiol compound. In this thesis, the best resistivity ρ of ECAs was 0.014 ohm-cm, and it was the ECAs of GS-75/Ag dispersed with 0.4g C4H9SH.