Semiconductor device with etch stop layer having greater thickness and method for fabricating the same

1. A semiconductor device, comprising:

a first semiconductor die comprising a first conductive layer;

a first etch stop layer positioned on the first conductive layer;

a second semiconductor die comprising a second conductive layer positioned above the first etch stop layer;

a second etch stop layer positioned on the second conductive layer;

a first through substrate via positioned along the second semiconductor die and the first etch stop layer, extended to the first semiconductor die, and positioned on the first conductive layer; and

a second through substrate via extended to the second semiconductor die, positioned along the second etch stop layer, and positioned on the second conductive layer;

wherein a thickness of the second etch stop layer is greater than a thickness of the first etch stop layer.

2. The semiconductor device of claim 1 , wherein the first etch stop layer and the second etch stop layer are formed of a same material.

3. The semiconductor device of claim 2 , wherein a ratio of the thickness of the second etch stop layer to the thickness of the first etch stop layer is between about 1.1 and about 2.0.

4. The semiconductor device of claim 3 , wherein a width of the second through substrate via is equal to or greater than a width of the first through substrate via.

5. The semiconductor device of claim 4 , further comprising a top conductive layer positioned on the first through substrate via and the second through substrate via.

6. The semiconductor device of claim 5 , further comprising isolation layers positioned on sidewalls of the first through substrate via, wherein the isolation layers are formed of silicon oxide, silicon nitride, silicon oxynitride, tetra-ethyl ortho-silicate, or combination thereof.

7. The semiconductor device of claim 5 , further comprising an adhesion layer positioned between the first conductive layer and the first through substrate via, wherein the adhesion layer is formed of titanium, tantalum, titanium tungsten, or manganese nitride.

8. The semiconductor device of claim 5 , further comprising a seed layer positioned between the first conductive layer and the first through substrate via, wherein the seed layer is formed of copper or ruthenium.

9. The semiconductor device of claim 6 , further comprising a first bonding layer positioned on the first etch stop layer and positioned between the first semiconductor die and the second semiconductor die.

10. The semiconductor device of claim 9 , wherein an aspect ratio of the second through substrate via is between about between about 1:6 and about 1:15.

11. The semiconductor device of claim 4 , wherein the second semiconductor die comprises a second dielectric layer positioned on the first bonding layer and a second substrate positioned on the second dielectric layer, the second conductive layer and the second etch stop layer are positioned in the second dielectric layer, and the second through substrate via is positioned along the second substrate, extended to the second dielectric layer, positioned along the second etch stop layer, and positioned on the second conductive layer.

12. The semiconductor device of claim 11 , wherein the second dielectric layer is formed of silicon oxide and the first etch stop layer and the second etch stop layer are formed of silicon nitride, silicon oxynitride, or silicon carbonitride.

13. The semiconductor device of claim 8 , wherein the seed layer has a thickness between about 10 nm and about 40 nm.