**4. Summary of this chapter and prospect for fabrication of the next-generation microelectronic devices**

In this chapter, lower-temperature process for fabrication of high-adhesion Cu/ glass stack was introduced. The surface activation bonding is one of the lowertemperature processes for similar- and dissimilar-material bonding. Also, roomtemperature formation process of intermixing layer is also introduced. A nanoscale ZnO layer improves the adhesion strength between Cu and glass even if metallization was carried out at room temperature. A Cu/glass stack with a high adhesion strength is successfully fabricated by the combination of Zn dope and noble metal catalyzation. This remarkable adhesion improvement is due to the effect of formation of an intermixing layer at interface. As well-known, Cu and SiO2 do not generally react at room temperature. Obviously, the noble metals lead to the intermixing acceleration, very likely by their catalytic effect.

These room-temperature/low-temperature processes achieve temperature reduction during microelectronic fabrication. In addition, it leads to formation of extremely thin (several nm thick) adhesion layer at the interface. The thickness reduction of adhesion layer can increase the area of the interconnection, and resistance of interconnection can be reduced. Therefore, these adhesion improvement processes at room temperature/low temperature is considered to be important for fabrication of a next-generation microelectronic device.
