Semiconductor structure along with multiple chips bonded through microbump and manufacturing method thereof
The present disclosure provides a semiconductor structure including a first chip having a first dielectric surface, a second chip having a second dielectric surface facing the first dielectric surface and maintaining a distance thereto, and an air gap between the second dielectric surface and the first dielectric surface. The first chip includes a plurality of first conductive lines in proximity to the first dielectric surface and parallel to each other, two adjacent first conductive lines each having a sidewall partially exposed from the first dielectric surface. The present disclosure further provides a method for manufacturing the semiconductor structure described herein.
1. A method for manufacturing a semiconductor structure, comprising:
receiving a first die having a first dielectric surface and a metal pad in proximity to the first dielectric surface;
forming a microbump on the metal pad through a plating operation;
receiving a second die having a plurality of conductive lines on a second dielectric surface of the second die;
exposing a sidewall of one of the plurality of conductive lines and an etch stop layer leveling with a bottom of one of the plurality of conductive lines by a first dielectric etching operation; and
bonding the first die and the second die through the microbump while maintaining a distance between the first dielectric surface and the second dielectric surface and thereby forming an air gap.
2. The method of claim 1 , wherein the first dielectric etching operation comprises an oxide recess operation.
3. The method of claim 1 , further comprising a deposition operation to seal the air gap, wherein the deposition operation comprises a blanket nitride deposition or an oxide deposition over the bonded first die and second die.
4. The method of claim 3 , wherein the oxide deposition comprises a TEOS deposition.
5. The method of claim 1 , wherein a portion of the metal pad is protruded from the first dielectric surface.
6. The method of claim 5 , wherein a sidewall of the portion of the metal pad is exposed by a second dielectric etching operation.
7. The method of claim 6 , wherein the first dielectric etching operation and the second dielectric etching operation are performed simultaneously.
8. The method of claim 1 , wherein each of the plurality of conductive lines are protruded from the second dielectric surface of the second die by the first dielectric etching operation.
9. The method of claim 1 , wherein the etch stop layer is formed prior to the formation of the conductive lines and the metal pad.
10. A method for manufacturing a semiconductor structure, comprising:
receiving a second chip having a metal pad in a top surface of the second chip;
forming a microbump on the metal pad;
receiving a first chip having a pad and a plurality of conductive lines embedded in a top surface of the first chip, wherein a sidewall of one of the plurality of conductive lines exposed by a first dielectric etching operation; and
bonding the first chip and the second chip through the microbump while maintaining a distance between the top surface of the first chip and the top surface of the second chip and thereby forming an air gap.
11. The method of claim 10 , further comprising:
exposing a sidewall of the metal pad by a second dielectric etching operation after the forming operation of the microbump.
12. The method of claim 10 , wherein a height of the microbump is from about 0.3 μm to about 5 μm.
13. The method of claim 10 , wherein the conductive lines are paralleled each other.
14. The method of claim 10 , wherein the first chip further comprises an etch stop layer leveling with a bottom of the pad.
15. A method for manufacturing a semiconductor structure, comprising:
receiving a first die having a first dielectric surface and a metal pad in proximity to the first dielectric surface;
forming a microbump having a planar top surface on the metal pad;
receiving a second die having a plurality of conductive lines protruded from a second dielectric surface of the second die, wherein an etch stop layer in the second die is exposed by a first dielectric etching operation; and
bonding the first die and the second die through the microbump while maintaining a distance between the first dielectric surface and the second dielectric surface and thereby forming an air gap.
16. The method of claim 15 , further comprising:
sealing the air gap laterally with a protection layer by a TEOS deposition or a blanket nitride deposition.
17. The method of claim 16 , wherein the protection layer comprises a concave curve laterally surrounding the air gap.
18. The method of claim 15 , wherein the protection layer is in contact with the etch stop layer.
19. The method of claim 15 , wherein a width of the air gap is at least equal to a width of the first die.
20. The method of claim 15 , wherein a plurality of sidewalls of each of the plurality of conductive lines are exposed from the second dielectric surface of the second die.