Semiconductor device and method for forming the same
A method for forming a semiconductor device includes the steps of providing a substrate having a memory region and a logic region, forming a memory stack structure on the memory region, forming a passivation layer covering a top surface and sidewalls of the memory stack structure, forming a first interlayer dielectric layer on the passivation layer, performing a post-polishing etching back process to remove a portion of the first interlayer dielectric layer and a portion of the passivation layer on the top surface of the memory stack structure, forming a second interlayer dielectric layer on the first interlayer dielectric layer and directly contacting the passivation layer, and forming an upper contact structure through the second interlayer dielectric layer and the passivation layer on the top surface of the memory stack structure to contact the memory stack structure.
1. A semiconductor device, comprising:
a substrate having a logic region and a memory region;
a first interlayer dielectric layer disposed on the substrate, wherein a thickness of the first interlayer dielectric layer on the memory region is smaller than a thickness of the first interlayer dielectric layer on the logic region;
a second interlayer dielectric layer disposed on the first interlayer dielectric layer;
a memory stack structure disposed in the first interlayer dielectric layer on the memory region;
a passivation layer covering a top surface and sidewalls of the memory stack structure, wherein the second interlayer dielectric layer directly contacts the passivation layer; and
an upper contact structure through the second interlayer dielectric layer and the passivation layer on the top surface of the memory stack structure and directly contacting the memory stack structure.
2. The semiconductor device according to claim 1 , wherein the thickness of the first interlayer dielectric layer on the logic region is different from the thickness of the first interlayer dielectric layer on the memory region by between 100 Å and 150 Å.
3. The semiconductor device according to claim 1 , wherein the first interlayer dielectric layer comprises a step portion near a boundary between the logic region and the memory region.
4. The semiconductor device according to claim 3 , wherein a step-height of the step portion is between 100 Å and 150 Å.
5. The semiconductor device according to claim 1 , wherein a portion of the passivation layer sandwiched between the top surface of the memory stack structure and the second interlayer dielectric layer has a thickness between 60 Å and 100 Å.
6. The semiconductor device according to claim 1 , further comprising:
a first interconnecting structure disposed in the first interlayer dielectric layer on the logic region; and
a second interconnecting structure disposed in the second interlayer dielectric layer and contacting the first interconnecting structure, wherein a height of the memory stack structure is smaller than a height of the first interconnecting structure.
7. The semiconductor device according to claim 1 , wherein the second interlayer dielectric layer comprises:
an etching stop layer contacting the first interlayer dielectric layer and the passivation layer; and
a dielectric material layer on the etching stop layer.
8. The semiconductor device according to claim 7 , wherein the etching stop layer comprises nitride doped silicon carbide, the dielectric material layer comprises a low-k dielectric material, and the passivation layer comprises silicon nitride.