Microfluidic laser equipment for semiconductor wafer processing

Microfluidic laser equipment for semiconductor wafer processing

Microjet laser technology is an advanced and widely used composite processing technology, which combines a water jet "as thin as a hair" with a laser beam, and guides the laser accurately to the surface of the machined part through total internal reflection in a manner similar to traditional optical fibers. The water jet continuously cools the cutting area and effectively removes the powder produced by processing.

As a cold, clean and controlled laser processing technology, microjet laser technology effectively solves the major problems associated with dry lasers, such as thermal damage, contamination, deformation, detritus deposition, oxidation, microcracks and taper.

Basic description of microjet laser machining

1. Laser type
Diode-pumped solid state Nd:YAG laser. The pulse width time is us/ns and the wavelength is 1064 nm, 532 nm, or 355 nm. Average laser power range 10-200 W.

2. Water jet system
Low pressure pure deionized filtered water. The water consumption of the ultrafine water jet is only 1 liter/hour at 300 bar pressure. The resulting force is negligible (< 0.1N).

3. Spout
Nozzle size range 30-150 um, nozzle material is sapphire or diamond.

4. Auxiliary system
High pressure pumps and water treatment systems.

Technical specifications

Application of microjet laser technology equipment

1. Wafer Cutting (Dicing)
Materials: Silicon (Si), silicon carbide (SiC), gallium nitride (GaN) and other hard and brittle materials wafer cutting.
Application: Replace traditional diamond blade, reduce edge breakage (edge breakage <5μm, blade cutting usually >20μm).
Cutting speed increased by 30% (for example, SiC wafer cutting speed up to 100mm/s).
Stealth Dicing: Laser modification inside the wafer, liquid jet assisted separation, suitable for ultra-thin wafers (<50μm).

2. Chip drilling and microhole processing
Application: Through silicon (TSV) drilling for 3D IC. Thermal microhole array machining for power devices such as IGBTs.
Technical parameters:
Aperture range: 10μm~200μm, depth to width ratio up to 10:1.
The pore wall roughness (Ra) <0.5μm is better than that of direct laser ablation (Ra>2μm).

3. Advanced Packaging
Application: RDL (Rewiring layer) Window opening: laser + jet removes passivation layer, exposing pad.
Wafer-level packaging (WLP) : Epoxy molding plastics (EMC) for Fan-Out packages.
Advantages: Avoid the chip warping caused by mechanical stress, and increase the yield to more than 99.5%.

4. Compound semiconductor processing
Material: GaN, SiC and other wide band gap semiconductor.
Application: Gate notch etching of HEMT devices: Liquid jet controls laser energy to avoid GaN thermal decomposition.
Laser Annealing: micro-jet local heating to activate the ion implantation zone (such as SiC MOSFET source).

5. Defect repair and fine tuning
Application: Laser fusing of redundant circuits in memory (DRAM/NAND).
Tuning of microlens arrays for optical sensors such as ToF.
Accuracy: energy control accuracy ±1%, repair position error <0.1μm.