HIGH-PRESSURE ALUMINUM FOR SUBMICRON VIAS USING A LIQUID TRANSDUCER

The manufacturing of ULSI sub-micron AlCu(0.5at%)Si(1at%) vias by a Li quid mediated high pressure filling process is studied. As the transdu cer silicone oil (polymethylsiloxane) is used. It is found that high p ressure via-fill can be performed for sub-micron vias in a wide proces s window (250-400 degrees C and 60-200 MPa). A threshold pressure (app rox. 50 MPa) is present below which no via-fill takes place. The tempe rature and pressure dependence of the extrusion process has been model led assuming an thermal activation. The activation energy of the defor mation process is 290 KJ mol(-1). The stress-state of the bridging Al thin film influences the filling capability of the process. It is foun d that tensile stress in the film causes a deterioration in the qualit y of the via-fill process.