Method for manufacturing shallow trench isolation in semiconductor device
The method for manufacturing an STI in a semiconductor device with an enhanced gap-fill property and leakage property is disclosed by introducing a nitridation process instead of forming a liner nitride. The method includes steps of: preparing a semiconductor substrate obtained by a predetermined process on which a pad oxide and a pad nitride are formed on predetermined locations thereof; forming an isolation trench with a predetermined depth in the semiconductor substrate; forming a wall oxide on the trench; forming a liner oxide on the wall oxide and an exposed surface of the pad nitride; carrying out a nitridation process for forming a nitrided oxide; forming an insulating layer over the resultant structure, wherein the isolation trench is filled with the insulating layer; and planarizing a top face of the insulating layer.
1. A method for manufacturing a shallow trench isolation (STI) in a semiconductor device, the method comprising the steps of:
a) preparing a semiconductor substrate obtained by a predetermined process on which a pad oxide and a pad nitride are formed on predetermined locations thereof;
b) forming an isolation trench with a predetermined depth in the semiconductor substrate;
c) forming a wall oxide on the trench;
d) forming a liner oxide on the wall oxide and an exposed surface of the pad nitride;
e) carrying out a nitridation process for forming a nitrided oxide;
f) forming an insulating layer over the resultant structure, wherein the isolation trench is filled with the insulating layer; and
g) planarizing a top face of the insulating layer,
wherein the step e) is carried out in an annealing furnace or a rapid thermal process (RTP) by using a nitrogen-containing gas selected from the group consisting of N 2 O, NO and NH 3 , thereby forming the nitrided oxide between the liner oxide and the wall oxide.
2. The method as recited in claim 1 , wherein the step e) is carried out by using NO gas as a source gas at a temperature in a range of about 750° C. to about 850° C.
3. The method as recited in claim 1 , wherein the step e) is carried out by using NH 3 gas as a source gas at a temperature in a range of about 750° C. to about 850° C.
4. The method as recited in claim 1 , wherein the step e) is carried out by using N 2 O gas as a source gas at a temperature in a range of about 800° C. to about 950° C.
5. The method as recited in claim 1 , wherein the step d) is carried out by repeating a chemical vapor deposition (CVD) process for forming a plurality of interfaces on the wall oxide.
6. The method as recited in claim 1 , wherein the step c) is carried out by using dry oxidation process on condition that a process temperature is in the range of about 850° C. to about 950° C. and a chlorine gas is supplied with amount in the range of about 0.1% to about 10%.
7. The method as recited in claim 1 , wherein the step f) is carried out by using a material selected from the group consisting of a high density plasma (HDP) oxide, an advanced planarized layer (APL) and a spin on dielectric (SOD).
8. A method for manufacturing an STI in a semiconductor device, the method comprising the steps of:
a) preparing a semiconductor substrate obtained by a predetermined process on which a pad oxide and a pad nitride are formed on predetermined locations thereof;
b) forming an isolation trench with a predetermined depth in the semiconductor substrate;
c) forming a wall oxide on the trench;
d) carrying out a nitridation process for forming a nitrided oxide on the wall oxide;
e) forming a liner oxide on the nitrided oxide;
f) forming an insulating layer over the resultant structure, wherein the isolation trench is filled with the insulating layer; and
g) planarizing a top face of the insulating layer,
wherein the step d) is carried out in an annealing furnace or a rapid thermal process (RTP) by using a nitrogen-containing gas selected from the group consisting of N 2 O, NO and NH 3 .
9. The method as recited in claim 8 , wherein the step c) is carried out by using dry oxidation process on condition that a process temperature is in the range of about 850° C. to about 950° C. and a chlorine gas is supplied with amount in the range of about 0.1% to about 10%.
10. The method as recited in claim 8 , wherein the step f) is carried out by using a material selected from the group consisting of an HDP oxide, an APL and an SOD.
11. The method as recited in claim 8 , wherein the step d) is carried out by using NO gas as a source gas at a temperature in a range of about 750° C. to about 850° C.
12. The method as recited in claim 8 , wherein the step d) is carried out by using NH 3 gas as a source gas at a temperature in a range of about 750° C. to about 850° C.
13. The method as recited in claim 8 , wherein the step d) is carried out by using N 2 O gas as a source gas at a temperature in a range of about 800° C. to about 950° C.