THICK Al-W STACKS WITH TiN BARRIER FOR BEOL APPLICATIONS
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
The multilevel interconnection structure, shown in Fig. 1, has been discussed in the prior art. The vertical studs may be made of metals other than W, but W is preferred for the reason of its electromigration performance. Such vertical studs may either fill vias (e.g., selective W) or form a column which is subsequently covered by insulator and planarized back to the stud. It is the second-type process which is described here. (Image Omitted) As can be seen in Figs. 2 and 3, the ability to pattern the W studs is clearly demonstrated. For this process, it is required to have a thickness of 1 mm W films on the 1 mm thick Al film for the upper level studs and lines. Figs. 2, 3, 4, 5 and 6 describe the processes, and the steps of Figs. 2, 3, and 4 are the subject of this publication.