Method for filling a gap in a three-dimensional structure on a semiconductor substrate
This application relates to a method of filling a gap in a three-dimensional structure over a semiconductor substrate. The method may include depositing a thin film at least on a three-dimensional structure over a substrate using at least one reaction gas activated with a first radio frequency (RF) power having a first frequency, the three dimensional structure comprising a trench and/or hole. The method may also include etching the deposited thin film using at least one etchant activated with a second RF power having a second frequency lower than the first frequency. The method may further include repeating a cycle of the depositing and the etching at least once until the trench and/or hole are filled with the thin film. According to some embodiments, a thin film having substantially free of voids and/or seams can be formed in the three-dimensional structure.
1. A method of filling a gap in a three-dimensional structure on a semiconductor substrate, the method comprising:
depositing a thin film for filling a trench and/or hole in the three-dimensional structure using a reaction gas activated with a first radio frequency (RF) power having a first frequency to form a deposited thin film;
etching the deposited thin film using an etchant activated with a second RF power having a second frequency lower than the first frequency; and
repeating a cycle of the depositing and the etching at least once until the trench and/or hole are filled with the thin film to form a thin film pattern, wherein the thin film pattern comprises a ratio of a volume of voids to a volume of the thin film that is less than 0.005.
2. The method of claim 1 , wherein the reaction gas comprises at least one of O 2 , O 3 , H 2 O, NO 2 , N 2 O, or a combination thereof.
3. The method of claim 1 , wherein the first frequency is in a range of about 100 kHz to about 3,000 MHz.
4. The method of claim 1 , wherein the first RF power is in a range of about 500 watt to about 3,000 watt.
5. The method of claim 1 , wherein the second frequency is in a range of about 100 kHz to about 5,000 kHz.
6. The method of claim 1 , wherein the second RF Power is in a range of about 100 watts to about 500 watts.
7. The method of claim 1 , wherein the first frequency is in a range of about 27.12 MHz to about 100 MHz, and wherein the second frequency is in a range of about 100 kHz to about 1,000 kHz.
8. The method of claim 1 , wherein the etchant comprises at least one of NF 3 , CIF 3 , F 2 , SF 6 , CF 4 , or a combination thereof.
9. The method of claim 1 , wherein in response to the etching, the deposited thin film is etched at different rates in different portions of the trench and/or hole.
10. The method of claim 1 , wherein the trench and/or hole has an aspect ratio of at least about 20:1.
11. The method of claim 10 , wherein:
the cycle of the depositing and the etching is repeated 1-10 times when a width of the trench and/or hole is at least about 200 nm,
the cycle of the depositing and the etching is repeated 1-20 times when the width of the trench and/or hole is in a range of about 150 nm to about 200 nm, and
the cycle of the depositing and the etching is repeated 1-40 times when the width of the trench and/or hole is about 100 nm or less.
12. The method of claim 1 , further comprising continuously flowing a carrier gas through the cycle of the depositing and the etching.
13. The method of claim 12 , further comprising supplying a source gas prior to supplying the first radio frequency (RF) power.
14. The method of claim 1 , wherein in response to the etching, a first portion of the thin film formed on an upper surface of the trench and/or hole is more etched than a second portion of the thin film formed on a remaining surface of the trench and/or hole.
15. The method of claim 14 , wherein in response to the etching, a third portion of the thin film formed on a middle surface of the trench and/or hole is more etched than a fourth portion of the thin film formed on a lower surface of the trench and/or hole.
16. The method of claim 15 , wherein in response to the etching, the first portion of the thin film is more etched than a fifth portion of the thin film formed on a top portion of the three-dimensional structure.
17. A method of filling a gap in a three-dimensional structure over a semiconductor substrate, the method comprising:
depositing a thin film for filling a trench and/or a hole in the three-dimensional structure by a vapor deposition process comprising contacting the three-dimensional structure with a reaction gas activated with a first radio frequency (RF) power having a first frequency to form a deposited thin film;
etching the deposited thin film using an etchant activated with a second RF power having a second frequency in a range of about 3 kHz to about 13,560 kHz, wherein the second frequency is different from the first frequency; and
repeating a cycle of the depositing and the etching at least once until the trench and/or hole are filled with the thin film to form a thin film pattern, wherein the thin film pattern comprises a ratio of a volume of voids to a volume of the thin film that is less than 0.005.
18. The method of claim 17 , wherein the depositing comprises activating the reaction gas with the first frequency in a range of about 100 kHz to about 3,000 MHz, and wherein the second frequency is in a range of about 100 kHz to about 1,000 kHz.
19. The method of claim 17 , wherein the etchant comprises at least one of NF 3 , CIF 3 , F 2 , SF 6 , CF 4 , or a combination thereof.