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

A laser beam machining method and a laser beam machining device capable of cutting a work without producing a fusing and a cracking out of a predetermined cutting line on the surface of the work, wherein a pulse laser beam is radiated on the predetermined cut line on the surface of the work under the conditions causing a multiple photon absorption and with a condensed point aligned to the inside of the work, and a modified area is formed inside the work along the predetermined determined cut line by moving the condensed point along the predetermined cut line, whereby the work can be cut with a rather small force by cracking the work along the predetermined cut line starting from the modified area and, because the pulse laser beam radiated is not almost absorbed onto the surface of the work, the surface is not fused even if the modified area is formed.

Laser processing method and laser processing apparatus

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

Multiphoton absorption is generated, so as to form a part which is intended to be cut 9 due to a molten processed region 13 within a silicon wafer 11, and then an adhesive sheet 20 bonded to the silicon wafer 11 is expanded. This cuts the silicon wafer 11 along the part which is intended to be cut 9 with a high precision into semiconductor chips 25. Here, opposing cut sections 25a, 25a of neighboring semiconductor chips 25, 25 are separated from each other from their close contact state, whereby a die-bonding resin layer 23 is also cut along the part which is intended to be cut 9. Therefore, the silicon wafer 11 and die-bonding resin layer 23 can be cut much more efficiently than in the case where the silicon wafer 11 and die-bonding resin layer 23 are cut with a blade without cutting a base 21.

Method for cutting semiconductor substrate

A method for making thin and dicing a substrate while preventing chipping or cracking. The method for dicing a substrate is characterized by comprising a step for forming a reformed region including a region subjected to melting through absorption of multiple photons in a semiconductor substrate (1) having functional elements (19) formed on the surface (3) by irradiating the semiconductor substrate (1) with a laser beam condensed at an inner point thereof and then forming a dicing starting point region in the reformed region including the region subjected to melting, and a step for polishing the rear surface (21) of the semiconductor substrate (1) such that the semiconductor substrate (1) has a specified thickness following the step for forming the dicing starting point region.

Method for dicing substrate

A laser apparatus comprises an optical resonator including first and second mirrors, and laser medium. An wavelength selection element is provided in the resonator for narrowing band-width. A polarizing conversion element for changing ratio of S to P components and polarizing beam splitter are provided for amplifying laser beam to output after wavelength selection and for reducing light load of the wavelength selection element. The polarizing conversion element is provided in the resonator light path. In another embodiment, the polarizing conversion element is provided in a branch light path formed by a second polarizing conversion element and a third mirror, where the second polarizing conversion element reflects and transmits P component at a given ratio and reflects S component. The wavelength selection element comprises a Fabry-Perot etalon, grating, or prism. The polarizing conversion element comprises a quarter-wave plate or a phase retarder mirror. The polarizing beam splitting element comprises a polarizing beam splitter or polarizing beam splitting prism. Such laser apparatus is suited for an exposure light source for photolithography.

Narrow-band laser apparatus

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor laser by which the manufacturing yield of the semiconductor laser can be improved by obtaining an optical resonator composed of a good cleavage plane without changing the characteristics of a compound semiconductor laminate by suppressing the occurrence of defects, such as cracking, chipping, etc., in a laser scribing method. SOLUTION: Ultrashort pulsed laser light 31 is projected upon a laminated substrate composed of a single-crystal oxide substrate 1 and the compound semiconductor laminate 10 having a stripe-like light emitting region perpendicularly to the stripe of the laminate 10 from the laminate 10 side. The wavelength of the laser light 31 is transparent to the laminate 10 and substrate 1. Consequently, a semiconductor laser element in which such defects as cracking, chipping, etc., do not occur and the characteristics of the laminate 10 do not change can be obtained by scribing 32 and 34 the incident plane and the plane opposite to the incident plane and cleaving (not shown in the figure) the planes.

Method of manufacturing semiconductor laser

PURPOSE:To enable the machining of a mass production in many kinds in reference to a laser beam machining device using plural fibers CONSTITUTION:This device is constituted of a laser generator 101, beam shaping means 102, plural optical fibers 105, machining head 108, and X-Y biaxial stage mechanism 114 for attaching an object to be machined It is so structured that a beam intercepting mechanism 106 be provided in the machining head 108 and that the head is movable The device is capable of a simultaneous machining with plural machining heads as well as a flexible application in machining in different sizes and a special machining Furthermore, loss of time in machining is controlled to a minimum

Laser beam machining device

A discharge-pumped gas laser (10) has a pressure container (11) filled with a laser gas under pressure and a pair of elongate main discharge electrodes (14,15). The main discharge electrodes (14,15) are disposed in the pressure container (11) in confronting relationship to each other for producing an electric discharge in the laser gas in a main discharge region (16) defined therebetween to excite the laser gas for laser emission. The laser gas is circulated to flow through the main discharge region (16) in a direction perpendicular to the main discharge electrodes (14,15). The laser gas in the main discharge region (16) is preionized by an UV preionizer (17,18) disposed either upstream or downstream of the main discharge region (16) with respect to the direction of flow of the laser beam. The pressure container (11) houses a baffle partition (33) for controlling the laser gas to flow past one of the main discharge electrodes (14,15) and the preionizer (17) while blocking the laser gas from directly flowing to the other of the main discharge electrodes (14,15) and the preionizer (18).

Discharge-pumped gas laser with baffle partition for controlled laser gas flow at preionizers

As a light source for deep submicron lithography the authors have developed a long life and high power KrF narrow band excimer laser by installing a polarization coupled resonator into the conventional narrow band excimer laser with intra-cavity etalons. A maximum output power of 1O. 5Yi with a low etalon-load of L5W arid a narrow spectral band-width of 24pm at 200Hz is obtained. The central wavelength is stabilized to within only 5pm and drift is not observed when increasing the repetition rate from 4Hz to 200Hz without a wavelength feedback loop system. Furthermore the etalon-life is expected to be drastically prolonged to over a billion pulses resulting from the reduction of the etalonload to only about 10 of that in a conventional laser. 2.

Keiichiro Yamanaka

Papers

Narrow-band laser apparatus

Method of manufacturing semiconductor laser

Laser beam machining device

Discharge-pumped gas laser with baffle partition for controlled laser gas flow at preionizers

High-power and narrow-band excimer laser with a polarization-coupled resonator