The invention provides a laser beam machining method characterized by comprising the steps of mounting a protective tape (25) on the surface (3) of a wafer (1a), radiating laser light (L) by using the back (21) of a wafer (1a) as a laser light incidence plane with an optical converging point (P) positioned in a substrate (15) to thereby form a melt processing region (13) for melt processing by multiphoton absorption, forming, by means of the melt processing region (13), a cutting start region (8) on the side within a predetermined distance from the laser light incidence plane along a predetermined cutting line (5) on the wafer (1a), mounting an expand tape (23) on the back (21) of the wafer (1a), and stretching the expand tape (23) to thereby separate a plurality of chip-like portions (24) from each other that are formed by the wafer (1a) being cut with the cutting start region (8) used as the starting point.

Laser beam machining method

Methods for ultrashort pulse laser processing of optically transparent materials. A method for scribing transparent materials uses ultrashort laser pulses to create multiple scribe features with a single pass of the laser beam across the material, with at least one of the scribe features being formed below the surface of the material. This enables clean breaking of transparent materials at a higher speed than conventional techniques. Slightly modifying the ultrashort pulse laser processing conditions produces sub-surface marks. When properly arranged, these marks are clearly visible with side-illumination and not clearly visible without side-illumination. In addition, a method for welding transparent materials uses ultrashort laser pulses to create a bond through localized heating. The ultrashort pulse duration causes nonlinear absorption of the laser radiation, and the high repetition rate of the laser causes pulse-to-pulse accumulation of heat within the materials. The laser is focused near the interface of the materials, generating a high energy fluence at the region to be welded. This minimizes damage to the rest of the material and enables fine weld lines.

Transparent material processing with an ultrashort pulse laser

A method of dividing a wafer having a plurality of devices, which are formed in a plurality of areas sectioned by streets formed in a lattice pattern on the front surface, and having test metal patterns which are formed on the streets, comprising the steps of: a laser beam application step for carrying out laser processing to form a dividing start point along a street on both sides of the test metal patterns by applying a laser beam along the street on both sides of the test metal patterns in the street formed on the wafer; and a dividing step for dividing the wafer which has been laser processed to form dividing start points along the dividing start points by exerting external force to the wafer, resulting in leaving the streets having the test metal patterns formed thereon behind.

Wafer dividing method

A laser processing method which can highly accurately cut objects to be processed having various laminate structures is provided. An object to be processed comprising a substrate and a laminate part disposed on the front face of the substrate is irradiated with laser light L while a light-converging point P is positioned at least within the substrate, so as to form a modified region due to multiphoton absorption at least within the substrate, and cause the modified region to form a starting point region for cutting. When the object is cut along the starting point region for cutting, the object 1 can be cut with a high accuracy.

Laser processing method

A TFT having stable characteristics is obtained by using a crystal silicon film obtained by crystallizing an amorphous silicon film by using nickel. Phosphorus ions are implanted to regions 111 and 112 by using a mask 109. Then, a heat treatment is performed to getter nickel existing in a region 113 to the regions 111 and 112. Then, the mask 109 is side-etched to obtain a pattern 115. Then, the regions 111 and 112 are removed by utilizing the pattern 115 and to pattern the region 113. Thus, a region 116 from which nickel element has been removed is obtained. The TFT is fabricated by using the region 116 as an active layer.

Method for fabricating semiconductor device

A laser beam processing machine comprising a path distribution means for distributing a pulse laser beam oscillated by pulse laser beam oscillation means to a first path and a second path alternately, and one laser beam that passes through one of the paths and is converged by one condensing lens and the other laser beam that passes through the other path and is converged by the condensing lens are applied at different focusing points which have been displaced from each other in the direction of the optical axis, alternately with a time lag between them.

Laser beam processing machine

PROBLEM TO BE SOLVED: To provide a wafer working method by which decomposed layers are formed along scheduled dividing lines of a wafer, and folding resistances of chips divided along the scheduled dividing lines formed with the decomposed layers can be improved. SOLUTION: A wafer working method for dividing a wafer by which functional elements are disposed in areas divided by lattice-shaped scheduled dividing lines on a front surface includes a decomposed layer forming step for forming a decomposed layer along the scheduled dividing lines inside the wafer by irradiating the wafer with a pulse laser beam that is permeable along the scheduled dividing lines; a dividing step for dividing the wafer into chips along the scheduled dividing lines by applying an external force along the scheduled dividing lines formed with the decomposed layers; a chip supporting step for disposing the divided chips on a supporting member while turning their rear surfaces upside with a space between each other; and a decomposed area removing step for removing the decomposed layers residual on side faces of the chips disposed on the supporting member with a space between each other. COPYRIGHT: (C)2005,JPO&NCIPI

Method of working wafer

PROBLEM TO BE SOLVED: To provide a silicon wafer laser machining method and a machining device through which a good modified layer can be formed along a division predetermined line inside a silicon wafer. SOLUTION: In the silicon wafer machining method, laser light irradiates the silicon wafer along the division predetermined line provided on it to form the modified layer along the division predetermined line inside the silicon wafer, wherein the wavelength of the laser light is set at 1100 to 2000 nm. COPYRIGHT: (C)2006,JPO&NCIPI

Laser machining method and device of silicon wafer

A wafer grinding method for grinding the surface to be ground of a wafer having an arcuatedly chamfered outer peripheral surface, comprising an outer peripheral portion removal step for removing the outer peripheral portion of the wafer by applying a laser beam from one surface side of the wafer along the outer periphery at a location on the inside of the outer periphery by a predetermined distance; and a grinding step for grinding the surface to be ground of the wafer whose outer peripheral portion has been removed, to a predetermined finish thickness

Wafer grinding method

PROBLEM TO BE SOLVED: To provide a method of grinding a wafer which can grind in a predetermined thickness without damaging it during grinding and without knife edge arising on the peripheral edge. SOLUTION: The method of grinding the surface to be ground of the wafer chamfered in a circular arc shape on the outer peripheral side includes an outer peripheral part removing step of removing the peripheral part of the wafer by irradiating along the peripheral edge in the position of a predetermined amount inside from the peripheral edge from one surface side of the wafer with a laser beam, and a grinding step of grinding the surface to be ground of the wafer in which the peripheral part is removed and forming it in a predetermined finishing thickness. COPYRIGHT: (C)2006,JPO&NCIPI

Yosuke Watanabe

Papers

Laser beam processing machine

Method of working wafer

Laser machining method and device of silicon wafer

Wafer grinding method

Method of grinding wafer