Device and method of dielectric layer
A method includes forming an interlayer dielectric (ILD) and a gate structure over a substrate. The gate structure is surrounded by the ILD. The gate structure is etched to form a recess. A first dielectric layer is deposited over sidewalls and a bottom of the recess and over a top surface of the ILD using a first Si-containing precursor. A second dielectric layer is deposited over and in contact with the first dielectric layer using a second Si-containing precursor different from the first Si-containing precursor. A third dielectric layer is deposited over and in contact with the second dielectric layer using the first Si-containing precursor. Portions of the first, second, and third dielectric layer over the top surface of the ILD are removed.
1. A method comprising:
forming a patterned mask over a substrate;
etching the substrate to form a plurality of fins by using the patterned mask as an etching mask;
depositing a first dielectric layer over sidewalls and a bottom of a trench between the fins and over a top surface of the patterned mask using a first Si-containing precursor, wherein the first precursor comprises Si w R x H y Cl z , w=1 or 2, and (x+y+z)>0;
depositing a second dielectric layer over and in contact with the first dielectric layer using a second Si-containing precursor, wherein the second precursor comprises Si(CH 2 )SiR′ a H b Cl c , where R′ is CH 3 or C 2 H 5 , (a+b+c)=6;
depositing a third dielectric layer over and in contact with the second dielectric layer using the first Si-containing precursor; and
removing excess portions of the first, second, and third dielectric layers over top surfaces of the fins.
2. The method of claim 1 , wherein the first, second, and third dielectric layers are deposited in the same chamber.
3. The method of claim 1 , wherein the first, second, and third dielectric layers are deposited at substantially the same temperature.
4. The method of claim 1 , wherein depositing the first dielectric layer is performed using a nitrogen-containing process gas.
5. The method of claim 1 , wherein depositing the second dielectric layer is performed using an oxygen-containing process gas.
6. The method of claim 1 , wherein depositing the third dielectric layer is performed using a nitrogen-containing process gas.
7. The method of claim 1 , wherein the first dielectric layer is substantially free from Si-C-Si.
8. The method of claim 1 , wherein the second dielectric layer comprises Si-C-Si.
9. The method of claim 1 , further comprising:
forming a fourth dielectric layer over and in contact with the third dielectric layer using the second Si-containing precursor.
10. The method of claim 1 , wherein the first dielectric layer comprises Si-C-O backbones.
11. A method comprising:
etching a semiconductor substrate to form a trench extending from a top surface of the semiconductor substrate into the semiconductor substrate;
depositing a first liner layer over sidewalls and a bottom of the trench using a first Si-containing precursor, wherein the first precursor comprises Si w R x H y Cl z , w>0, and (x+y+z)>0;
depositing a second liner layer conformally over the first liner layer using a second Si-containing precursor, wherein the second precursor comprises Si(CH 2 )SiR′ a H b Cl c , where R′ is CH 3 or C 2 H 5 , (a+b+c)=6;
depositing a third liner layer conformally over the second liner layer using the first Si-containing precursor;
filling a dielectric material into the trench and over the third liner layer; and
removing excess portions of the dielectric material over the top surface of the semiconductor substrate.
12. The method of claim 11 , further comprising:
depositing a fourth liner layer conformally over the third liner layer using the second Si-containing precursor to fill the dielectric material into the trench.
13. The method of claim 11 , wherein the first Si-containing precursor comprises Si-Si.
14. The method of claim 11 , wherein the second Si-containing precursor comprises Si-C-Si.
15. A method comprising:
forming a trench in a substrate;
forming a composite dielectric layer into the trench, wherein forming the composite dielectric layer comprises:
depositing a first dielectric layer in the trench using a first precursor, wherein the first precursor comprises Si w R x H y Cl z , where R is CH 3 or C 2 H 5 , w=1 or 2, (x+y+z)=2w+2, and(x+y+z)>0;
depositing a second dielectric layer over the first dielectric layer using a second precursor, wherein the second precursor comprises Si(CH 2 )SiR′ a H b Cl c , where R′ is CH 3 or C 2 H 5 , (a+b+c)=6, and (a+b+c)>0; and
performing a CMP process to the first dielectric layer and the second dielectric layer until a top surface of the substrate is exposed.
16. The method of claim 15 , further comprising performing depositing the first dielectric layer and depositing the second dielectric layer in an alternate manner.
17. The method of claim 15 , wherein the first precursor further comprises C x H y , where 2≤x≤4.
18. The method of claim 15 , wherein a carbon-containing material is not added during depositing the first dielectric layer, such that a carbon concentration in the second dielectric layer is higher than a carbon concentration in the first dielectric layer.
19. The method of claim 15 , wherein depositing the first dielectric layer is performed using a process gas comprising nitrogen, such that a nitrogen concentration in the first dielectric layer is higher than a nitrogen concentration in the second dielectric layer.
20. The method of claim 15 , wherein depositing the first dielectric layer and depositing the second dielectric layer are performed in a same chamber with a same temperature.