利用銅/鑽石/矽複合材料當作高亮度發光二極體的散熱管理

Abstract

本研究主要提出以銅/鑽石/矽複合材料直接與晶片端接觸，提供一個導熱的通道以改善高亮度發光二極體焦耳熱效應的問題。研究一共分為兩個主題：首先是在矽晶圓上製作規則的凹槽陣列，接著將人造鑽石顆粒填入凹槽，以電鍍銅的方式固定並填補凹槽，接著再將發光二極體結構轉移到高散熱的鑽石複合基板。使用鑽石主因是鑽石是熱的良導體，相較於原本的藍寶石基板有更佳的散熱性質，可以使元件在更高的飽和電流下驅動，以達到高功率的目標，銅則是做為固定鑽石及導熱用途。然而鑽石的硬度極高並且無法導電，所以矽晶圓的部分就提供了後續製程的切割走道以及導電的通道。

主題二是在矽晶圓上製作一個單層高密度分布的人造鑽石顆粒，利用晶圓接合技術，選擇適當的接合材料做為封裝的固晶材料。在實驗中分為製作單層高密度分佈銅/人造鑽石複合層與焊錫、BCB（Bzocyclobutene）接合、並且與銅和焊錫做結構熱阻量測分別分析討論。在封裝領域提供一個新的想法藉由鑽石的高導熱性質，來提升固晶材料的散熱能力。

In this thesis, the main idea is to produce a direct heat dissipated channel by let artificial diamond particles directly contact with the chip side. The thesis includes two themes: first part, the artificial diamond particles were filled into the patterns on Si wafer,and electroplating Cu to fix the diamond. Then we transferred Sapphire substrate of LED to this high thermal conductivity Cu/diamond/Si composite substrate. The reason for this process is that diamond have better heat dissipation properties compared with the sapphire substrate. With better heat dissipation the transferred LED device could be operated in a much higher injection forward current and provide much higher output power. However, diamond is extremely hard and not conductive, so the Cu and Si aisle played an important role in electrical conduction. Si aisle also act as a cutting aisle for the LED transfer process. There are several issues including: pattern choice, how to fill artificial diamonds, wafer bonding, laser lift-off, and device fabrication. We change experimental conditions and processes for our desired device. The second theme is the producing of high distribution single artificial diamond layer on Si wafer, and selecting the appropriate bonding material as die-attach material. The experiment is divided into several part. Production of a high distribution single artificial diamond layer on star board, bonding with solder, BCB（Bzocyclobutene）and Cu. Structural thermal resistance measurement were analyzed and discussed. To sum up, we propose a new idea in electric packaging by using diamond which has high thermal conductivity to improve the ability of heat dissipation of die-attach material.