Semiconductor device and method for fabricating the same
A method for fabricating semiconductor device includes the steps of: providing a substrate having a memory region and a periphery region; forming a first trench and a second trench in substrate on the memory region, wherein a width of the second trench is greater than a width of the first trench; forming a first liner, a second liner, and a third liner in the first trench and the second trench; performing a surface treatment process to lower stress of the third liner; and planarizing the third liner, the second liner, and the first liner to form a first isolation structure and a second isolation structure.
1. A semiconductor device, comprising:
a substrate having a memory region and a periphery region;
a first isolation structure in the substrate on the memory region, wherein the first isolation comprises:
a first liner in the substrate;
a second liner on the first liner; and
a third liner on the second liner, wherein a top surface of the third liner is planar;
a second isolation structure adjacent to the first isolation structure, wherein a width of the second isolation structure is greater than a width of the first isolation structure, the second isolation structure comprises:
the first liner in the substrate;
the second liner on the first liner;
the third liner on the second liner, wherein a top surface of the third liner comprises a V-shape;
a fourth liner on the third liner, wherein the fourth liner comprises a V-shape; and
a fifth liner on the fourth liner, wherein a top surface of the fifth liner is planar.
2. The semiconductor device of claim 1 , further comprising a third isolation structure in the substrate on the periphery region, wherein a width of the third isolation structure is greater than a width of the second isolation structure.
3. The semiconductor device of claim 2 , wherein the third isolation structure comprises:
the first liner in the substrate;
the second liner on the second liner; and
the third liner on the second liner.
4. The semiconductor device of claim 3 , further comprising:
the fourth liner on the third liner in the second isolation structure and the third isolation structure;
the fifth liner on the fourth liner in the second isolation structure and the third isolation structure; and
a sixth liner on the fifth liner in the third isolation structure.
5. The semiconductor device of claim 4 , wherein the third liner and the fourth liner comprise different materials.
6. The semiconductor device of claim 4 , wherein the third liner comprises silicon nitride and the fourth liner comprises silicon oxide.
7. The semiconductor device of claim 4 wherein the third liner and the fifth liner comprise a same material.
8. The semiconductor device of claim 7 , wherein the third liner and the fifth liner comprise silicon nitride.
9. The semiconductor device of claim 1 , wherein the first liner and the second liner comprise silicon oxide.