Multilevel Metallization and the Need for Planarization

FIGURE 1.1 A cross section SEM image of a representative multilevel interconnect network (from Ref. 9). 

FIGURE 1.2 Devices fabricated without (left) and with (right) planarization (from Ref. 10). 

A comparison between a planarized and nonplanarized surface topography is shown in Fig. 1.2. By meeting the depth of focus requirement for the photolithographic step, CMP eliminated several yield-related issues such as missing contacts, undesired current leaks, and electromigrations [11-19]. 

---