Disco Corporation

Tomoki Yoshino

Hiroshi Morikazu

Kazuya Hirata

Yoko Nishino

Takumi Shotokuji

A laser processing method includes holding a single crystal silicon wafer as a workpiece, selecting a laser beam having a wavelength of 1950 nm or more in a transmission wavelength region to the single crystal silicon wafer, and applying the laser beam to the single crystal silicon wafer along a predetermined area with the focal point of the laser beam set inside the wafer, thereby forming a plurality of shield tunnels arranged along the predetermined area. Each shield tunnel is composed of a fine hole and an amorphous region formed around the fine hole for shielding the fine hole. The fine hole extends from a beam applied surface of the wafer where the laser beam is applied to the other surface opposite to the beam applied surface.

Laser processing apparatus and laser processing method

Disclosed herein is a wafer processing method for dividing a wafer into individual device chips along division lines. The wafer processing method includes a frame supporting step of attaching the wafer to an adhesive tape fixed at its peripheral portion to an annular frame, thereby supporting the wafer through the adhesive tape to the annular frame, a laser processing step of applying a laser beam to each division line to thereby form a strength reduced portion along each division line, and a dividing step of applying a radial tension to the adhesive tape and next applying an external force to the wafer in the condition where the radial tension is kept acting on the adhesive tape, thereby dividing the wafer into the individual device chips along the division lines.

Wafer processing method

A wafer is produced from an ingot having an end surface. The method includes an end surface measuring step of measuring undulation present on the end surface, and a separation plane forming step of setting the focal point of a laser beam inside the ingot at a predetermined depth from the end surface, which depth corresponds to the thickness of the wafer to be produced, and next applying the laser beam to the end surface to thereby form a separation plane containing a modified layer and cracks extending from the modified layer. The height of an objective lens for forming the focal point of the laser beam is controlled so that the focal point is set in the same plane to form the separation plane, according to the numerical aperture NA of the lens, the refractive index N of the ingot, and the undulation present on the end surface.

Wafer producing method

In a wafer processing method, the back side of a wafer is attached to an adhesive tape supported at its peripheral portion by an annular frame having an inside opening. The wafer is set in the inside opening, thereby supporting the wafer through the adhesive tape to the annular frame. The wafer is held on a chuck table with the front side of the wafer facing the upper surface of the chuck table. A laser beam is applied through the adhesive tape and the back side of the wafer in an area corresponding to each division line, thereby forming a plurality of shield tunnels arranged along each division line. Each shield tunnel extends from the front side of the wafer to the back side thereof, each shield tunnel being composed of a fine hole and an amorphous region formed around the fine hole for shielding the fine hole.

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Tokyo, Japan

Tomoki Yoshino