| 摘要 |
PURPOSE:To obtain a structure having large heat sink effect adapted for a chip of large area by reducing the thickness of an Si substrate on the lower surface of an element active unit, and securing another Si substrate via an alloy layer on the substrate except the active unit. CONSTITUTION:A hole is opened in the prescribed size at an Si substrate 5 which is mirror-polished, a thermally oxidized film 6 is covered, and an unnecessary part is removed. A bipolar transistor 1 is formed on another Si substrate 2, and a Ti-Pt-Au layer 7' is superposed on an SiO2-Si3N4 film 6'. After SiO2 on the back surface of the substrate 5 is completely removed with HF aqueous solution, it is intimately contacted with the substrate 2, treated at 400-450 deg.C, and secured by an AuSi layer 7. The substrates 2, 5 are superposed so that the orientations of the crystal axes are coincided. Then, the back surface of the substrate 2 is polished to form the thickness to approx. 20mum and a Ti-AuSb film 2 is deposited. The substrate 5 is then scribed, divided, the substrate 2 is also simultaneously divided, and the elements on the substrate are isolated into chips. |
