本計晝目的為利用Cu/Pd間原子快速交互擴散的特性發展Cu/Pd固態擴散金屬鍵合技術。由初 步的研究成果我們發現，在Cu/Pd鍵合時改變適當的銅微結構有提升Cu/Pd間交互擴散係數的現 象。所以，本計晝將研究銅微結構對Cu/Pd間擴散行為提升的效應，並研究出一適當應力施加範圍， 可以將鍵結溫度能降低到150°C以下。我們認為可透過應力施予及調控銅的優選方向可進一步降低 Cu/Pd鍵合溫度。而低溫鍵合可有效減少晶圓鍵結所產生的熱應力破壞元件的效能。本計晝主要方 向是將銅鈀的固態擴散接合溫度可以低於150°C以下，三年研究分為四大部份討論：（1)不同應力下 之Cu/Pd交互擴散行為探討;(2)不同晶格優選方向（不同晶粒大小)之銅電鍍層對Cu/Pd交互擴散行 為探討並建立完整低溫Cu/Pd鍵合系統；（3)將低溫Cu/Pd擴散鍵合系統應用在thin-GaN LED之製 程技術開發；（4)研究不同低溫Cu/Pd鍵合製程條件對thin-GaN垂直式LED的光電表現的影響。 ;Three-dimensional integrated circuit (3D IC) has been considered as the key process for the next generation semiconductor technology. Also, wafer-to-wafer bonding technology also has advantages on thin-GaN vertical LED because of (1) uniform current spreading and (2) high emitting area. Therefore, wafer-to-wafer technology would be an important technology in the future. For 3D IC package and wafer to wafer bonding technology, solid/solid metal bonding has demonstrated to be a suitable process in low temperature. The solid diffusional bonding has many merits, such as, (1) no formation of intermetallic compounds (IMC) at the bonding interface, (2) Avoid the residual stress produced by CTE mismatch in high temperature process. In this proposal, we will develop Cu/Pd bonding. Importantly, an applied external stress can enhance the bonding interface and reduce the bonding temperature. Therefore, we propose three-year project focusing on developing a low-temperature Cu/Pd bonding process below 150°C. The entire three-years project breaks down to the following two main items: (1) Under an external stress, the inter-diffusion barrier energy of Cu/Pd inter-diffuse in different preferred orientation and the different grain size of the electroplating copper layer. (2) Fabricate vertical thin-GaN LED by lower bonding temperature Cu/Pd bonding process.
