Method and device for machining wafer by using laser

Abstract

The invention provides a method and device for machining a wafer by using laser. According to the method, by changing the relative position between a laser beam and the upper surface of the wafer, a groove is formed in the upper surface of the wafer; and the laser beam comprises laser sub beams, and laser focuses of the laser sub beams are distributed three-dimensionally. By adopting the method and device for machining the wafer by using the laser, a three-dimensionally distributed light spot combination can be formed in the wafer by the laser focuses through treatment, three-dimensional-level machining on the upper surface of the wafer is achieved and a Low-K layer of the upper surface of the wafer is removed efficiently, and further the working efficiency and the precision of the machining method and the evenness of the separated wafer are enhanced.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method and device for laser processing wafers. Background technique [0002] In recent years, with the continuous reduction of the feature size of semiconductor devices and the continuous improvement of chip integration, the parasitic capacitance between metal interconnections and multilayer wiring and the resistance of metal wires have increased sharply, resulting in RC delays, A series of problems such as increased power consumption limit the development of high-speed electronic components. When the feature size of the device is less than 90nm, the wafer must use a low dielectric constant material (hereinafter referred to as "Low-K") material instead of the traditional SiO 2 Layer (K ​​= 3.9 ~ 4.2), commonly used Low-K materials include Dow Corning's FOx and porous SiLK materials, Applied Materials' black diamond series low-K thin film materials, Novellus System's COR...

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Problems solved by technology

[0004] However, when the laser is used to cut the wafer, since the intensity distribution of the laser light source conforms to the Gaussian distribution, that is, the light intensity is the strongest at the center of the spot, and the energy at the edge of the spot decreases gradually according to the characteristics of the Gaussian distribution. When the optically processed Gaussian spot is cut with a single beam, the center of the spot is prone to strong thermal burning phenomenon, and then the heat-affected area is larger and damages the wafer

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