They may also contain advanced low K layers which have proven difficult to process using conventional mechanical techniques, such as dicing saws. Emerging 45 and 65 nm node logic devices may contain greater than eight metal layers, typically aluminum and copper. The recent development of high average power (> 10 W), 100 KHz, enables an attractive short pulsewidth laser process alternative to existing nanosecond process technologies, particularly for laser micromachining of complex alloy structures.
Laser micromachining is employed on these devices to form cut-outs, microvias, and perform partial material removal, including scribing and dicing operations. Both the simulation and experimental results demonstrate that a QCW laser machine with a high-NA focus lens is ideal for wafer stealth dicing.Īdvanced semiconductor logic devices are increasingly complex, typically composed of multiple layers of dielectric, metal, and semiconductor materials. An optothermal model used to simulate the dicing process and calculate the temperature was implemented numerically based on the Crank-Nicolson algorithm and the successive over-relaxation method. We redesigned the focusing lens of a QCW metal-cutting laser machine to form a cutting head with a high numerical aperture (NA) that is suitable for wafer stealth dicing. In this study, we proposed a low-cost method for wafer stealth dicing using quasi-continuous wave (QCW) lasers. The existing stealth dicing process that utilizes an ultrashort pulse laser is expensive. Stealth dicing technology, which produces laser irradiation inside the wafer to form a modified layer within the wafer without any damage to the surface, is an alternative and advanced dicing process that is in line with the future trend of thin wafers.
As memory device packaging moves toward die stacking technology with thin chips of high density, wafer dicing has recently become a key factor in semiconductor yield.
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