Thinned substrate manufacturing method

A manufacturing method of manufacturing a plurality of chips from a first substrate including a protruding portion formed along an outer circumferential edge and a small thickness portion having an outside surrounded by the protruding portion, the first substrate having one surface to which a protective member is fixed, the manufacturing method comprising:

• holding the first substrate by a holding surface of a holding plate;
• setting an inner circumferential edge of a removal region, the inner circumferential edge being configured to define an external shape of a second substrate having a predetermined size, in the small thickness portion located inward of an outer circumferential edge of the holding surface;
• setting an outer circumferential edge of the removal region in the first substrate such that the outer circumferential edge of the removal region is located at a middle point between the inner circumferential edge of the removal region and the outer circumferential edge of the holding surface or located outward of the middle point in a radial direction of the first substrate;
• separating the second substrate from the first substrate by removing the removal region in a thickness direction of the first substrate;
• peeling off the protruding portion and the small thickness portion between the outer circumferential edge of the removal region and the protruding portion from the protective member by moving the protruding portion and the second substrate relative to each other, after separating the second substrate from the first substrate;
• and
• dividing the second substrate into the plurality of chips after peeling off the protruding portion and the small thickness portion between the outer circumferential edge of the removal region and the protruding portion from the protective member.

A setting method of setting a removal region in a first substrate to separate, as a second substrate, a part of a small thickness portion of the first substrate including a protruding portion formed along an outer circumferential edge and the small thickness portion having an outside surrounded by the protruding portion, the first substrate having one surface to which a protective member is fixed, the setting method comprising:

• holding the first substrate by a holding surface of a holding plate;
• setting an inner circumferential edge of the removal region, the inner circumferential edge being configured to define an external shape of the second substrate, in the small thickness portion located inward of an outer circumferential edge of the holding surface;
• and
• setting an outer circumferential edge of the removal region in the first substrate such that the outer circumferential edge of the removal region is located at a middle point between the inner circumferential edge of the removal region and the outer circumferential edge of the holding surface or located outward of the middle point in a radial direction of the first substrate.