MEMS (Micro-Electro-MeChanical System), that is, microelectronic mechanical system, generally composed of micro-mechanical structures, microsteps, micronepermers, and control circuits, and MEMS is a chip between different energy forms by semiconductor processes.
The MEMS wafer’s scribe method is different from a typical IC. A typical IC grinding wheel is rotated by a high speed of the grinding wheel to complete the removal of the material, thereby achieving chip cutting. Due to the high speed of the blade, it is often necessary to use pure water to cool and rinse, then the pressure and torque generated by the blade high speed rotation, the impact force of pure water, the pollution caused by the cut SI, is easily mechanical to MEMS chip Microstructure causes irreversible damage. Therefore, the typical IC’s grinding wheel disconnect does not apply to MEMS wafers.
Laser invisible cutting as a solution of laser cutting wafers, very good to avoid problems with grinding scribe. The laser invisible cut is to focus on the surface of the material by optical shaping by optical shaping, allowing the material surface to be focused in the material, and the energy density of the focus area is high, forming a multi-photon absorption nonlinear absorption effect, so that the material is modified to form cracks. Each laser pulse is equivalent to form an alternative damage to form a modified layer inside the material. The molecular bonds of the modified layer position material are destroyed, and the attachment of the material is fragile and easy to separate. After the cutting is completed, the product is fully separated by stretching the carrier film, and a gap is generated between the chip and the chip. Such processing methods avoid damage caused by the direct contact of the machine and the flushing of pure water. At present, laser invisible cutting techniques can be applied to sapphire / glass / silicon and a plurality of compound semiconductor wafers.
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