Abstract:
A process is described for forming a common input-output (I/O) site that is suitable for both wire-bond and solder bump flip chip connections, such as controlled-collapse chip connections (C4). The present invention is particularly suited to semiconductor chips that use copper as the interconnection material, in which the soft dielectrics used in manufacturing such chips are susceptible to damage due to bonding forces. The present invention reduces the risk of damage by providing site having a noble metal on the top surface of the pad, while providing a diffusion barrier to maintain the high conductivity of the metal interconnects. Process steps for forming an I/O site within a substrate are reduced by providing a method for selectively depositing metal layers in a feature formed in the substrate. Since the I/O sites of the present invention may be used for either wire-bond or solder bump connections, this provides increased flexibility for chip interconnection options, while also reducing process costs.
Abstract:
A structure comprising a free-standing polyamic acid film substantially free of phthalic acids. A method of fabricating such a structure which comprises applying a polyamic acid solution to a substrate, partially or substantially completely removing the solvent from the polyamic acid solution by heating the same, removing the free-standing polyamic acid film which is free from phthalic acids, laminating the film to a substrate at elevated temperature and pressure and thermally curing the laminated, free-standing polyamic acid film to the corresponding polyimide. A structure comprising one or a plurality of such free-standing polyamic acid films with electrically conducting layers therebetween is also disclosed as is a method of fabricating such a structure. Further disclosed is the use of a thermoplastic polyimide adhesive precursor which permits 2nd level multilayer packaging applications and a method for forming such packaging.