Method for the rapid processing of polymer layers in support of imidization processes and fan out wafer level packaging including effiecient drying of precursor layers
AssigneeYield Engineering Systems, Inc.
InventorWilliam Moffat
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Abstract
A process for the drying, and subsequent imidization, of polyimide precursors which minimizes or eliminates voids and which minimizes or eliminates discoloration. The process uses a sequential set of descending pressure operations that allow for time efficient processing of wafers. The set of descending pressure operations are interspersed with evacuation processes using heated gasses, which combine heating and byproduct evacuation. The process results in layers with reduced or eliminated voiding, discoloration, and solvent retention.
Claims17
A process for drying of substrates in support of temperature imidization of polymer layers, said process comprising the steps of:
- inserting one or more substrates into a process chamber, said one or more substrates coated with a layer of polyimide precursor, said polyimide precursor comprising N-Methyl-2-pyrrolidone;
- reducing the pressure in said process chamber to a first drying pressure;
- first flushing said process chamber with inert gas to a first flushing pressure;
- reducing the pressure in said process chamber to a second drying pressure after said first flushing, wherein said second drying pressure is lower than said first drying pressure;
- second flushing said process chamber with inert gas to a second flushing pressure after the step of reducing the pressure in said process chamber to a second drying pressure;
- reducing the pressure in said process chamber to a third drying pressure after the step of second flushing said process chamber, wherein said third drying pressure is lower than said second drying pressure;
- and
- third flushing said process chamber with inert gas to a third flushing pressure after the step of reducing the pressure in said process chamber to a third drying pressure.
Dependencies are inferred from the claim text.