Semiconductor structure and manufacturing method thereof

A semiconductor structure, comprising:

• a first die, having a first bonding structure, wherein the first bonding structure includes a first bonding film;
• a planarizing guard structure, disposed on the first die, wherein the planarizing guard structure has a first dielectric layer disposed on the first bonding film and a second dielectric layer disposed on the first dielectric layer, wherein the planarizing guard structure has a cavity opening penetrating through the planarizing guard structure and revealing a top surface of the first bonding film;
• a second die, disposed on the first die and located in the cavity opening of the planarizing guard structure, wherein the second die has a dielectric portion and a semiconductor material portion disposed on the dielectric portion, and a top surface of the dielectric portion is not higher than a top surface of the planarizing guard structure, so that sidewalls of the dielectric portion is covered by the planarizing guard structure;
• and
• a filling material layer, disposed over the second die, on the planarizing guard structure and covering the semiconductor material portion of the second die, wherein a sidewall of the dielectric portion forms an acute angle with the top surface of the first bonding film.

A method for forming a semiconductor structure, comprising:

• providing a substrate having a first bonding structure formed thereon, wherein the first bonding structure includes a first bonding film;
• forming a first dielectric layer over the substrate covering the first bonding structure, wherein the first dielectric layer has a first thickness;
• forming a second dielectric layer over the substrate covering the first dielectric layer, wherein the second dielectric layer has a second thickness, and a material of the second dielectric layer is different from a material of the first dielectric layer;
• forming a cavity opening penetrating through the first dielectric layer and the second dielectric layer to reveal a top surface of the first bonding structure;
• disposing a die on the top surface of the first bonding structure revealed by the cavity opening, wherein the die has a dielectric portion and a semiconductor material portion disposed on the dielectric portion, the dielectric portion has a third thickness, and a sum of the first thickness and the second thickness is equivalent to or larger than the third thickness;
• and
• forming a filling material layer on the die and over the substrate without filling into the cavity opening, wherein the filling material layer covers the semiconductor material portion of the die and the second dielectric layer, wherein a sidewall of the dielectric portion forms an acute angle with a top surface of the first bonding film.