Abstract: A wafer level package that incorporates dual stress buffer layers for achieving I/O pad redistribution and a method for forming the package are disclosed. In the package, a first stress buffer layer and a second stress buffer layer are sequentially deposited on top of an IC die by a method such as spin coating, laminating, screen printing or stencil printing of an elastic material which has a Young's modulus of less than 10 MPa. A suitable thickness for the first and the second stress buffer layer is between about 10 &mgr;m and about 70 &mgr;m. Metal traces are formed on top of the first and the second stress buffer layer for connecting a first plurality of I/O pads and a second plurality of I/O pads to achieve I/O redistribution.

Abstract: A method for forming a wafer level package by incorporating an insulating pad of an elastic material under a dummy plug is described. In the method, a multiplicity of pads or islands formed of an elastic material is first formed on a pre-processed semiconductor substrate before a multiplicity of dummy via plugs are formed on top. The dummy via plugs are used as a support structure for building I/O redistribution lines (i.e. metal traces) thereon such that I/O bond pads may be built for supporting solder bumps or solder balls. The multiplicity of insulating pads is used for stress relief during a bonding process with the solder ball built on top without the conventional defect of cracking due to high elasticity of the material when a large area insulating layer is deposited on top.

Abstract: A method for simultaneous bumping/bonding an IC chip to a semiconductor substrate and a semiconductor package fabricated by the method are described. In the method, a plurality of edge-type conductive pads formed of under-bump-metallurgy layers are first fabricated on an IC chip by dicing through conductive pads formed on a silicon wafer. The edge-type conductive pads, or UBM layer, are then positioned in close proximity to conductive elements formed on a top surface of a semiconductor substrate. A volume of solder is then applied to the interface between the conductive pads and the conductive elements to form electrical bonds between the two. A suitable method for applying the volume of solder may be a solder jetting technique, a solder printing technique or a method utilizing pre-applied solder paste on the surfaces to be bonded together.

Abstract: An IC die formed with built-in stress test pattern and a method for forming such pattern are described. The stress test pattern may be formed by first forming a thermal oxide insulation layer on a silicon substrate, then forming a first plurality of diagonally positioned linear metal traces of a first metal, then depositing an electrically insulating material layer on top of the first plurality of diagonally positioned metal traces, and forming a second plurality of L-shaped metal bars of a second metal positioned with the two sides of L parallel to the two sides of a corner region and overlapping the first plurality of metal traces with the electrically insulating material layer therein between. The double metal method for forming the stress test pattern can be easily incorporated into the fabrication process for an IC die without any additional deposition or photolithographic steps.

Abstract: An extended flip chip ball grid array package includes a metal heat slug bonded to the surface of a semiconductor chip. The heat slug has a bonding structure for connecting itself and a BGA substrate panel on which the semiconductor chip is mounted. The heat slug protects the chip from being damaged as well as assists heat dissipation. A first package assembly provides contact bodies on the heat slug for bonding the heat slug to contact pads formed on a BGA substrate panel. A second package assembly fixes the heat slug to a supporting structure bonded on a BGA substrate panel. Supporting stubs are formed on the supporting structure and snapped in openings formed on the contact bodies of the heat slug. Conventional packaging or testing equipment can be used for both package assemblies to manufacture or test the semiconductor chip packages.