Method of manufacturing element chip and element chip

A method of manufacturing an element chip, in which a plurality of element chips are formed by dividing a substrate, which includes a first surface having a plurality of element regions defined by dividing regions, and a second surface on a side opposite to the first surface, at the dividing regions, the method comprising:

• a preparing step of preparing the substrate in which a first surface side of the substrate is supported on a carrier and an etching-resistant layer is formed so as to cover regions of the second surface opposite to the element regions and to expose regions of the second surface opposite to the dividing regions;
• and
• a plasma processing step of performing plasma processing on the substrate that is supported on the carrier after the preparing step,
• wherein the plasma processing step includes
• a dividing step of dividing the substrate into the element chips by etching the substrate of regions which are not covered by the etching-resistant layer in a depth direction of the substrate up to the first surface by exposing the second surface to first plasma and causing the element chips including the first surface, the second surface, and a side surface connecting the first surface and the second surface to be in a state of being held spaced from each other on the carrier,
• an ashing step of removing the etching-resistant layer, and
• a protection film forming step of forming a protection film selectively on the side surface of any one or more of the element chips by exposing the element chips to second plasma generated during supplying of protection film forming gas in a state where the element chips are held spaced from each other on the carrier after the dividing step,
• wherein in the protection film forming step, a high-frequency bias is applied to a stage on which the carrier is mounted, and
• wherein the ashing step is performed after the dividing step and before the protection film forming step.