Wafer processing method

Abstract

A wafer processing method of processing a wafer having an epitaxial film formed on the front side. The wafer processing method includes a holding step of holding the wafer on a holding table having a holding surface for holding the wafer and a rotational axis extending perpendicularly to the holding surface and passing through the center of the holding surface, and a removing step of pressing a grinding member on a ridge portion formed along the peripheral edge of the wafer held on the holding table and rotating the holding table about the rotational axis, thereby removing the ridge portion.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a wafer processing method of processing a wafer having an epitaxial film formed on the front side.[0003]2. Description of the Related Art[0004]Epitaxial growth on the front side of a semiconductor crystal substrate (wafer) of silicon (Si) or the like causes undesirable formation of a ridge portion of an epitaxial film, called edge crown, along the peripheral edge of the wafer. To cope with this problem, the peripheral edge of the wafer is generally formed with a chamfered portion to suppress the occurrence of abnormal growth in the epitaxial growth, i.e., the formation of the edge crown and to also prevent the occurrence of cracking or chipping due to the contact of the peripheral edge of the wafer in handling or transporting the wafer.[0005]However, when the epitaxial film has a large thickness, the height of the edge crown is increased to more than 10 μm in some cases. In such a wafer,...

AI Technical Summary

Benefits of technology

The present invention aims to provide a method for processing wafers with epitaxial films that prevents damage to the devices and ensures proper suction holding of the wafer during subsequent steps. This is achieved by removing a ridge portion formed along the peripheral edge of the wafer that may cause damage or lead to ineffective suction holding. The method is applicable to different types of wafers.

Problems solved by technology

However, there is a case that the chamfered portion is small or no chamfering is performed depending on the kind of the wafer.

There is a possibility that the edge crown (ridge portion of the epitaxial film) formed on the front side of the wafer along the peripheral edge thereof may be broken during transportation of the wafer to cause damage to the devices formed on the front side of the wafer.

Further, when an edge crown is formed on the back side of the wafer, there is a possibility that faulty suction holding of the wafer may occur in holding the back side of the wafer under suction in a subsequent step.

However, there is a case that no chamfering is performed on an SiC wafer.

When an epitaxial film is formed on the SiC wafer by epitaxial growth, edge crowns are formed on the front side and back side of the wafer along the peripheral edge thereof, causing the damage to the devices formed on the front side of the wafer or the faulty suction holding of the wafer in the subsequent step.

Images