Method and system for scribing brittle ultrathin piece by water jet and laser

Abstract

The invention discloses a method and system for scribing a brittle ultrathin piece by a water jet and laser. According to the method, a laser beam penetrates through a water jet beam to focus on the surface of a workpiece; the distance between the center of the jet point, on the surface of the workpiece, of the water jet beam and the center of the focus point, on the surface of the workpiece, of the laser beam is equal to or smaller than 1-2.5 times the radius of the focus point, on the surface of the workpiece, of the laser beam. The distance between an intersection point I and an intersection point II is equal to or smaller than 1-2.5 times the radius of the focus point of the laser beam, wherein the intersection point I is the intersection point of the surface of the workpiece and the water jet beam generated by the jet nozzle of the system, and the intersection point II is the intersection point of the surface of the workpiece and the laser beam. The longitudinal center line of the jet nozzle coincides with the center line of the laser beam. A workbench is provided with a working cavity filled with water; a water layer with a thickness of 0.5-1.5 mm is arranged on the surface of the workpiece on the top surface of a boss at the top of the workbench; the overflow port of the working cavity is connected to a water tank; a water pump is used for pumping water in the water tank into the jet nozzle to generate the water jet. According to the invention, the laser is used for laser ablating and scribing, and the water jet beam is used for cooling and washing a processed area, so that the effect that a processed surface is free from recast layers, residual stress and micro cracks is achieved; the processing efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of laser processing, in particular to a method and system for marking ultra-thin sheets of brittle materials with water jet laser. Background technique [0002] For electronic products, the market trend of "light, thin, short, and small" has changed the packaging of integrated circuits from a single chip to a stacked package of multi-layer chips. 7-8 layers of chips are superimposed in an IC, and the total volume after packaging is reduced to a fraction of the previous single-layer chip IC. Therefore, the thickness of the silicon wafer has also been reduced from 650 μm to 120 μm, and the lowest has reached 25 μm. Before the silicon wafer is diced, the whole wafer is processed, and after dicing, the single chip used in the IC packaging process is obtained. Due to the increase in wafer diameter and thinning in thickness, the tensile and extrusion strength of the wafer is getting weaker and weaker, and it is ...

AI Technical Summary

Problems solved by technology

However, it is difficult to control the focused laser beam to align with the micro-water column in its equipment, and a little carelessness will lead to ablation and damage to the nozzle that produces the water column

The aspect ratio of the nozzle is required to reach 20, the hole diameter is extremely small, and the production material is not easy to obtain, and the consumable nozzle increases the cost of using this method

In addition, the conversion of high-pressure and low-speed water flow into a low-pressure, high-speed and stable micro-water column through the water cavity is also difficult to control. The optical path of the beam in the water column is long, and the energy loss of stimulated Raman scattering is large.

These technical difficulties lead to the high price of micro-waterjet laser equipment and high equipment maintenance costs, which greatly limit the application of this technology

[0006] For this reason, in recent years, Dr. Richerzhagen and others have studied the composite processing of water-guided laser micromachining and diamond cutting, and explored a method to combine the processing performance advantages of the two processes. However, due to the more complicated equipment, it is difficult to apply it in practice.

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