Advanced monitoring method for copper interconnect process

Stabilizing copper interconnect process is the key for yield and reliability improvement. Forming adequate grains in a copper film is so important to have the stable process, but there is no proper method of monitoring grains in a copper film. We introduce an advanced method of monitoring grain size using scattering light that we call the micro-haze method. We verified the effectiveness of the method by the experimental design and concluded that the method makes it possible to monitor grains in a copper film.