利用電鍍銅技術製作高散熱複合基板 作為散熱管理

Abstract

隨著科技進步，電子裝置朝著高效能、高頻率的趨勢發展，元件尺寸要求則越微小、精細，由於元件尺寸變小，散熱變得困難，大量的熱能累積在元件上，會進一步影響元件的表現，因此散熱是相當重要的議題。本研究選用鑽石作為高散熱複合基板的材料，鑽石比原本的砷化鎵基板有更佳的散熱性質。藉由晶圓接合技術將LED從砷化鎵基板轉移到銅/矽/鑽石複合材料上，期望能藉由提升基板的散熱，進而改善發光二極體焦耳熱效應的問題，使得元件能在更高電流下操作。 研究分為兩個主題，主題一是利用預先電鍍的方式製作高散熱複合基板，首先在矽晶圓上製作規則排列的凹槽陣列，作為複合基板之框架，接著填入人造鑽石，並利用電鍍銅固定鑽石，最後利用晶圓接合技術將砷化鎵磊晶片與複合基板做接合。主題二是利用預先接合的方式製作高散熱複合基板，先將砷化鎵磊晶片與圖形化矽基板接合，接著研磨背面的矽直到露出凹槽陣列，最後填入鑽石並電鍍完成基板的製作。由於銅具延展性以及鑽石硬度高取不導電，造成基板不易切割成所需大小，因此圖形化矽基板提供了後續切割的走道及導電的走道。

With the advance of science and technology, the electronic component is moving in the direction with high efficiency. Under high current, the Joule heating is the main reason leads to the low performance of electronic component. Therefore, heat dissipation is an important issue. In this thesis, we choose diamond as an integral part of high thermal dissipation composite substrate because diamond has higher thermal conductivity than GaAs substrate. We transfered light emitting diode from GaAs substrate to Copper/Silicon/Diamond composite substrate by wafer bonding. We hope to solve the problem of Joule heating effect, so that the transferred LED device could be operated in a much higher injection forward current and provide much higher output power with better heat dissipation. The thesis includes two themes. In the first part, we fabricate the high thermal dissipation composite substrate by pre-electroplating. We prepare silicon wafer with patterned pits. Then artificial diamond particles are filled into the patterns on silicon wafer and fixed by the method of copper electroplating. At last, we transfer LED to composite substrate. The second part is to high thermal dissipation composite substrate by pre-bonding. The patterned Si substrate is bonded with Epitaxial Wafer, and then the back of Si substrate is removed by grinding. At last, artificial diamond particles are filled into the patterns on silicon wafer and fixed by the method of copper electroplating. Although diamond material has high thermal conductivity, it is extremely hard and not conductive. Silicon and copper aisle played an important role in electrical conduction. Si aisle also act as a cutting aisle for the LED transfer process.