LASER PROCESSING METHOD

• US 20200135563A1
• Filed: 10/14/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Disco Corporation
• Original Assignee: Disco Corporation
• Inventors: MORIKAZU, Hiroshi
• Granted Patent: US 11,114,341 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 2101/42 Printed circuits
• CPC Class Codes: B23K 2103/54 Glass
• CPC Class Codes: B23K 2103/56 semiconducting semiconducting devices B23K2101/40
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 26/362 Laser etching
• CPC Class Codes: B23K 26/386 of blind holes
• CPC Class Codes: B23K 26/402 involving non-metallic material, e.g. isolators
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/76898 formed through a semiconductor substrate
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32
• CPC Class Codes: H01L 2224/05025 the internal layer being disposed on a via connection of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/05144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 24/05 of an individual bonding area
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/40102 being pulsed
• CPC Class Codes: H01L 2924/40501 UV spectrum

Abstract

A laser processing method for a substrate with a device formed on a front surface thereof and including an electrode pad, the method including: a laser beam applying step of applying the laser beam to the back surface of the substrate to form a fine hole in the substrate at a position corresponding to the electrode pad; a detecting step of detecting first plasma light emitted from the substrate at the same time that the fine hole is formed in the substrate by the laser beam applied thereto, and second plasma light emitted from the electrode pad; and a laser beam irradiation finishing step of stopping application of the laser beam when the second plasma light is detected in the detecting step. A peak power density of the laser beam to be applied is set in a range from 175 GW/cm² or less to 100 GW/cm² or more.

Claims

1. A laser processing method for applying a laser beam to a back surface of a substrate with a device formed on a front surface thereof and including an electrode pad, to form a fine hole in the substrate that reaches the electrode pad, the method comprising:

a laser beam applying step of applying the laser beam to the back surface of the substrate to form a fine hole in the substrate at a position corresponding to the electrode pad;

a detecting step of detecting first plasma light emitted from the substrate at the same time that the fine hole is formed in the substrate by the laser beam applied thereto, and second plasma light emitted from the electrode pad; and

a laser beam irradiation finishing step of stopping application of the laser beam when the second plasma light is detected in the detecting step,

wherein, in the laser beam applying step, a peak power density of the laser beam to be applied is set in a range from 175 GW/cm² or less to 100 GW/cm² or more.

2. The laser processing method according to claim 1,

wherein, in the laser beam applying step, a peak power density of the laser beam to be applied is set in a range from 150 GW/cm² or less to 125 GW/cm² or more.