Method for forming a wafer level package incorporating a multiplicity of elastomeric blocks and package formed
AssigneeIndustrial Technologies Research Institute
InventorsSzu-Wei Lu, Ming Lu, Jyh-Rong Lin
Life of this patent
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Abstract
A method for forming a wafer level package incorporating a multiplicity of elastomeric blocks as stress buffering layer and package formed are described. The method incorporates the step of forming metal lines in-between the plurality of IC dies on a wafer during the same process used for forming the metal vias. The metal lines are subsequently removed by either a mechanical method such as dicing with a diamond saw or by a chemical method such as wet etching. The method allows the fabrications of a wafer level package that has a multiplicity of elastomeric blocks formed on top as stress buffering layer without the CTE mismatch problem with other layers on the wafer.
Claims12
A method for forming a wafer level package incorporating a multiplicity of elastomeric blocks comprising the steps of:
- providing a wafer that is pre-processed with a plurality of IC dies formed on a top surface, each of said plurality of IC dies being spaced-apart from its immediately adjacent IC dies by a distance that is at least a width of a scribe line, each of said plurality of IC dies further having a multiplicity of input/output pads formed on top;
- depositing a first metal layer on said top surface of the wafer;
- depositing a photoresist layer of at least 20 μm thickness on said first metal layer;
- forming a plurality of trench openings separating said plurality of IC dies and a plurality of via openings with each on one of said multiplicity of input/output pads exposing said first metal layer;
- depositing a second metal into and filling said plurality of trench openings forming a plurality of metal lines and said plurality of via openings forming a plurality of metal vias;
- removing said photoresist layer and said first metal layer not covered by said plurality of metal vias;
- and
- depositing an elastomeric material on top of said wafer filling cavities formed between said plurality of metal lines forming said multiplicity of elastomeric blocks.
Dependencies are inferred from the claim text.