Processing method for wafer

Abstract

A processing method for a wafer includes: a cut groove forming step of forming a cut groove having depth corresponding to complete thickness of a device chip from a front side of a wafer along a division line by a cutting tool; and a sealing step of sealing the front surface of the wafer using a sealing material; an aligning step of receiving the front surface side of the wafer by the sealing material through an infrared light receiving unit from the front surface side of the wafer, detecting an alignment mark, and detecting a division line to be laser-processed based on the alignment mark; amodified layer forming step of emitting a laser beam of such a wavelength as to pass through the sealing material along the division line from the front surface side of the wafer, wherein a focal point of the laser beam in the sealing material is positioned in the cut grooves to form modified layers in form the sealing material; a grinding step of grinding the wafer from a back surface side of thewafer to the finished thickness of each of the device chips to expose the sealing material in the cut grooves; and a dividing step for applying an external force on the sealing material in the cut grooves and parts of the wafer having the modified layers serving as starting points of the division into individual component chips each having its front surface and four side surfaces surrounded by the sealing material.

Description

technical field [0001] The invention relates to a wafer processing method, and the wafer is processed to form a 5S mold package. Background technique [0002] As a structure to achieve miniaturization and high-density mounting of various devices such as LSI and NAND flash memory, for example, a chip size package (CSP) in which device chips are packaged in chip sizes has been put into practical use, And it is widely used in mobile phones, smart phones, etc. In addition, among these CSPs, in recent years, a CSP that seals not only the front surface of a chip but also the entire side surface of a chip with a sealing material, that is, a so-called 5S molded package, has been developed and put into practical use. [0003] Conventional 5S molded packages are produced through the following steps. [0004] (1) External connection terminals called devices (circuits) and bumps are formed on the front surface of a semiconductor wafer (hereinafter, sometimes roughly referred to as a w...

AI Technical Summary

Problems solved by technology

[0013] However, in the alignment method described in the above publication, instead of the cutting tool for dicing, it is necessary to attach a wide cutting tool for edge trimming to the spindle to remove the sealing material on the outer peripheral portion of the wafer. It takes time and labor to replace the cutting tool and remove the sealing material on the outer peripheral part by edge trimming, and there is a problem of poor productivity

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