Challenges to Planarization technologies for the next generation
When ultra low-k materials acting as interlayer dielectric films are applied to semiconductor devices, the mechanical strength of the devices becomes so weak that low down force planarization technology is vital for semiconductor manufacturing of the next generation.
Two candidate processes, electro-chemical polishing-contacted (ECP-C) and electro mechanical polishing in de-ionized water (ECP-DI), have been investigated extensively.
As an example of investigation results, a polymer in electrolyte of ECP-C was found considerably influential to the polishing performance. Figure 1 shows the difference in surface roughness of Cu polished substrates with and without a polymer in a testing electrolyte.
(a) Electrolyte without a polymer
(Rmax = 1248 nm)
(b) Electrolyte with a polymer
(Rmax = 48 nm)
Fig.1 Effect of a polymer in a testing electrolyte in a Cu ECP-C process
For details, see the following references:
“Surface Roughness Performance of Electro Chemical Mechanical Polishing (ECMP)”, ADMETA2006 Asian Session, pp. 72-73.
“The development of Electro Chemical Mechanical Polishing (ECMP) solution”, Proceedings of JSPE Autumn Conference, 2007, Vol. 2007A (2007), pp. 1007-1008. (in Japanese)
