Polymer nanofiber environmental barrier structure

A method for producing a Micro Electro Mechanical System (MEMS) chip with an environmental barrier structure made from polymer nanofibers, the method comprising:

• providing a wafer substrate having a front side and an opposite back side;
• forming a plurality of through holes in the wafer substrate;
• creating the environmental barrier structure by applying the polymer nanofibers onto the front side or the back side of the wafer substrate, the polymer nanofibers being densely connected to form a connected web that covers the wafer substrate including the through holes formed therein;
• and
• singulating a plurality of MEMS chips from the wafer substrate by applying a two-step laser process comprising
• a first laser-processing step comprising guiding a laser with a wavelength between about 300 nm and about 400 nm focused on the polymer nanofibers over the front side or the back side of the wafer substrate at which the polymer nanofibers are applied in order to locally remove the polymer nanofibers from the wafer substrate and to locally uncover an underlying surface, and
• a subsequent second laser-processing step comprising applying a stealth dicing process by guiding a stealth dicing laser with a wavelength between about 1000 nm and about 1100 nm focused inside of the wafer substrate over the locally uncovered underlying surface.

A method for producing a Micro Electro Mechanical System (MEMS) chip with an environmental barrier structure made from polymer nanofibers, the method comprising:

• providing a wafer substrate having a front side and an opposite back side;
• forming a plurality of through holes in the wafer substrate;
• providing a rigid mesh covering at least one of the through holes, wherein the rigid mesh is flush with the front side or the back side of the wafer substrate;
• creating the environmental barrier structure by applying the polymer nanofibers onto the front side or the back side of the wafer substrate at which the rigid mesh is applied, the polymer nanofibers being densely connected to form a connected web that covers the wafer substrate including the through holes formed therein;
• and
• singulating a plurality of MEMS chips from the wafer substrate by applying a two-step laser process comprising
• a first laser-processing step comprising guiding a laser over the front side or the back side of the wafer substrate at which the polymer nanofibers are applied in order to locally remove the polymer nanofibers from the wafer substrate and to locally uncover an underlying surface comprising silicon oxide, and
• a subsequent second laser-processing step comprising applying a stealth dicing process by guiding a stealth dicing laser over the locally uncovered silicon oxide underlying surface.