LASER DICING DEVICE AND DICING METHOD

摘要

A laser dicing device includes a laser light source, an AF light source, a light path of the processing laser light and a light path of the AF laser light being partially shared with each other, a condenser lens arranged on the shared light path between the first laser light and the second laser light, an AF signal processing unit that generates a focus error signal based on reflected light of the AF laser light reflected by the surface of the wafer, a controller that moves the condenser lens such that a distance between the condenser lens and the surface of the wafer is made constant based on the focus error signal, and a focus lens group that adjusts the position of the condensing point of the AF laser light in a state where the position of the condensing point of the processing laser light is fixed.

主权项

1. A laser dicing device which forms a modified region inside a wafer by condensing a first laser light inside the wafer, comprising:
a first laser light source configured to emit the first laser light; a second laser light source configured to emit a second laser light to be reflected by a surface of the wafer, the second laser light source having a light path which is partially shared with a light path of the first laser light; a condenser lens configured to condense the first laser light and the second laser light, the condenser lens being arranged on a first shared light path between the light path of the first laser light and the light path of the second laser light; a light splitter which is arranged on the light path of the second laser light and is configured to split a reflected light of the second laser light reflected by the surface of the wafer from the light path of the second laser light to a split path; a pinhole arranged between the second laser light source and the light splitter; a focus error signal generator which includes a light detector configured to receive the reflected light of the second laser light having been split to the split path by the light splitter and is configured to generate a focus error signal indicating a distance between a condensing point of the second laser light and the surface of the wafer, based on the reflected light of the second laser light which is received by the light detector; a controller configured to move the condenser lens in a thickness direction of the wafer based on the focus error signal so as to make a distance between the condenser lens and the surface of the wafer constant; and a condensing point adjuster configured to adjust a position of the condensing point of the second laser light in the thickness direction of the wafer in a state where a position of a condensing point of the first laser light is fixed, wherein the condensing point adjuster is at a position on the light path of the second laser light independent from the first shared light path, and the condensing point adjuster is arranged on a second shared light path between the second laser light and the reflected light of the second laser light.