Chip bonding method and semiconductor chip structure

A chip bonding method, comprising:

• providing a first chip, wherein the first chip comprises a first substrate comprising a first surface and a second surface which are arranged to be opposite, and the first chip further comprises a first groove on a side of the first surface of the first substrate and a first contact pad in the first groove, the first contact pad comprises a first portion and a second portion, the first portion is lower than the first surface of the first substrate and the second portion is higher than the first surface of the first substrate, so as to form the first contact pad which is stepped;
• providing a second chip, wherein the second chip comprises a second substrate comprising a third surface and a fourth surface which are arranged to be opposite, and the second chip further comprises a second groove on a side of the third surface of the second substrate and a second contact pad in the second groove, the second contact pad comprises a third portion and a fourth portion, the third portion is lower than the third surface of the second substrate and the fourth portion is higher than the third surface of the second substrate, so as to form the second contact pad which is stepped;
• bonding the first chip and the second chip, wherein the first portion of the first chip contacts with the fourth portion of the second chip, and the second portion of the first chip contacts with the third portion of the second chip;
• and
• forming a gap between the first contact pad and the second contact pad after bonding the first chip and the second chip;
• wherein the first chip further comprises a first through hole structure, the first through hole structure is disposed in the first substrate, and is on a side of the second surface of the first substrate, and a projection image of the gap falls within a projection image of the first through hole structure in a projection perpendicular to a plane direction of the first substrate;
• wherein the first groove is disposed above the first through hole structure;
• and
• wherein the second chip further comprises a second through hole structure, the second through hole structure is disposed in the second substrate, and is on a side of the fourth surface of the second substrate, and a projection image of the gap falls within a projection image of the second through hole structure in a projection perpendicular to a plane direction of the second substrate;
• wherein the second groove is disposed above the second through hole structure.