Wafer processing method

Abstract

To provide a wafer processing method capable of suppressing reduction in bending strength of chips when a wafer having a functional layer laminated on a substrate is processed into the chips.SOLUTION: A wafer processing method for processing a wafer 100 having a functional layer 120 laminated on a substrate 110 along a plurality of dividing scheduled lines includes a processing groove forming step of removing the functional layer 120 by radiating a laser beam along the dividing scheduled lines to form processing grooves 150 that expose the substrate 110, a damaged region removing step of removing a damaged region generated at an interface between the substrate 110 and the functional layer 120 in the processing groove forming step, and forming recessed portions 170 extending outward from side surfaces of the processing grooves 150, and a recessed portion exposing step of removing the functional layer 120 covering upper parts of the recessed portions 170 to expose the recessed portions 170, and a substrate processing step of processing the substrate 110 along the dividing scheduled lines after the recessed portion exposing step is executed.SELECTED DRAWING: Figure 5

Claims

[Claim 1] A wafer processing method for processing a wafer in which a functional layer is laminated on a substrate along multiple planned division lines, A processing groove forming step involves irradiating a laser beam along the planned division line to remove the functional layer and form a processing groove that exposes the substrate, The process includes removing the damaged area generated at the interface between the substrate and the functional layer by the groove formation step, and forming a recess that extends outward from the side of the groove, A recess exposure step involves removing the functional layer covering the upper part of the recess to expose the recess, After the recess exposure step is performed, a substrate processing step is performed to process the substrate along the planned division line, A wafer processing method characterized by having the following features. [Claim 2] A wafer processing method for processing a wafer in which a functional layer is laminated on a substrate along multiple planned division lines, A processing groove forming step involves irradiating a laser beam along the planned division line to remove the functional layer and form a processing groove that exposes the substrate, The process includes removing the damaged area generated at the interface between the substrate and the functional layer by the groove formation step, and forming a recess that extends outward from the side of the groove, A recess exposure step involves removing the functional layer covering the upper part of the recess to expose the recess, After the recess exposure step is performed, a substrate processing step is performed to process the substrate along the planned division line, Equipped with, A wafer processing method characterized in that different etching gases are used for etching in the damaged area removal step and etching in the recess exposure step. [Claim 3] The wafer processing method according to claim 1 or claim 2, characterized in that the substrate processing step is carried out by plasma etching, in which the recess from which the damaged area has been removed and the side surface of the processing groove are covered with a side protective film, thereby preventing the recess and the processing groove from expanding horizontally, while the bottom surface of the processing groove is excavated. [Claim 4] The wafer processing method according to claim 1 or claim 2, characterized in that the recess exposure step is carried out by plasma etching. [Claim 5] The process further comprises a top protective film forming step, in which a top protective film is formed on the functional layer before the groove forming step is carried out. The wafer processing method according to claim 1 or claim 2, characterized in that the upper protective film and the functional layer are removed in the groove forming step.

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