Sandia Corporation

William R Conley

Kenneth A Peterson

The present invention relates to a method of protecting a microelectronic device during device packaging, including the steps of applying a water-insoluble, temporary protective coating to a sensitive area on the device; performing at least one packaging step; and then substantially removing the protective coating, preferably by dry plasma etching. The sensitive area can include a released MEMS element. The microelectronic device can be disposed on a wafer. The protective coating can be a vacuum vapor-deposited parylene polymer, silicon nitride, metal (e.g. aluminum or tungsten), a vapor deposited organic material, cynoacrylate, a carbon film, a self-assembled monolayered material, perfluoropolyether, hexamethyldisilazane, or perfluorodecanoic carboxylic acid, silicon dioxide, silicate glass, or combinations thereof. The present invention also relates to a method of packaging a microelectronic device, including: providing a microelectronic device having a sensitive area; applying a water-insoluble, protective coating to the sensitive area; providing a package; attaching the device to the package; electrically interconnecting the device to the package; and substantially removing the protective coating from the sensitive area.

Temporary coatings for protection of microelectronic devices during packaging

A method is disclosed for pre-release plastic packaging of MEMS and IMEMS devices. The method can include encapsulating the MEMS device in a transfer molded plastic package. Next, a perforation can be made in the package to provide access to the MEMS elements. The non-ablative material removal process can include wet etching, dry etching, mechanical machining, water jet cutting, and ultrasonic machining, or any combination thereof. Finally, the MEMS elements can be released by using either a wet etching or dry plasma etching process. The MEMS elements can be protected with a parylene protective coating. After releasing the MEMS elements, an anti-stiction coating can be applied. The perforating step can be applied to both sides of the device or package. A cover lid can be attached to the face of the package after releasing any MEMS elements. The cover lid can include a window for providing optical access. The method can be applied to any plastic packaged microelectronic device that requires access to the environment, including chemical, pressure, or temperature-sensitive microsensors; CCD chips, photocells, laser diodes, VCSEL's, and UV-EPROMS. The present method places the high-risk packaging steps ahead of the release of the fragile portions of the device. It also provides protection for the die in shipment between the molding house and the house that will release the MEMS elements and subsequently treat the surfaces.

Pre-release plastic packaging of MEMS and IMEMS devices

The present invention relates to a method of protecting a microelectronic device during device packaging, including the steps of applying a water-insoluble, protective coating to a sensitive area on the device; performing at least one packaging step; and then substantially removing the protective coating, preferably by dry plasma etching. The sensitive area can include a released MEMS element. The microelectronic device can be disposed on a wafer. The protective coating can be a vacuum vapor-deposited parylene polymer, silicon nitride, metal (e.g. aluminum or tungsten), a vapor deposited organic material, cynoacrylate, a carbon film, a self-assembled monolayered material, perfluoropolyether, hexamethyldisilazane, or perfluorodecanoic carboxylic acid, silicon dioxide, silicate glass, or combinations thereof. The present invention also relates to a method of packaging a microelectronic device, including: providing a microelectronic device having a sensitive area; applying a water-insoluble, protective coating to the sensitive area; providing a package; attaching the device to the package; electrically interconnecting the device to the package; and substantially removing the protective coating from the sensitive area.

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Tijeras, NM, United States of America

William R Conley