Laser Lift-off (LLO)

Laser Lift-off


Overview of Laser Lift-Off (LLO) Process

With the Laser Lift-Off (LLO) processing technology, the inside of the processing material is irradiated with a high-power laser, heated, and decomposed in a planar orientation. Then, the processing material is separated from the processed area which serves as the base point for detachment. Although an excimer laser was mainly used for the existing LLO processes, the diode pumped solid state (DPSS) has increasingly been adopted for LLO in recent years. DISCO uses a DPSS laser for the LLO process, which realizes much less equipment maintenance time (by reducing the frequency of replacing consumable products and adjusting the optical axes) and a more stable processing quality. DISCO has adopted its original optical system for the LLO process to keep the processing margin wide even for wafers with a large amount of warpage and to prevent the wafer from being damaged. In addition, the surface roughness after detachment becomes one-third of the current value.

Processing example of V-LED
(Processing example of V-LED)

Precision Processing Equipment to Be Used

Fully-Automatic Laser Lift-Off (Fully-automatic detaching equipment using a laser)

Fully-Automatic Laser Lift-Off

The laser saws currently available have various automated functions. Wafer transfer, automatic recognition of the processing position, and automatic detaching functions are included, so the processing materials can be fed cassette by cassette. Substrates after the detachment process are contained in a separate cassette.

Precision Processing Tools to Be Used

Diode pumped solid state (DPSS)

Applications of the Laser Lift-Off (LLO) Process

・Sapphire substrate detaching process for devices such as micro LED (μ-LED)
・Detaching process of ultrathin wafers with backside metal, such as power devices (e.g. Si, SiC, and GaN)

Materials Processed with This Process