Method for forming silicon oxide cap layer for solid state diffusion process

• US 9,607,837 B1
• Filed: 12/21/2015
• Issued: 03/28/2017
• Est. Priority Date: 12/21/2015
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Namba, Kunitoshi
• Primary Examiner(s): Everhart, Caridad
• Assistant Examiner(s): Singal, Ankush
• Application Number:
  US14/977,291
• Time in Patent Office: 463 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02129 the material being boron or phosphorus doped silicon oxides, e.g. BPSG, BSG or PSG
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/2255 the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
• CPC Class Codes: H01L 21/2256 through the applied layer

Abstract

A method for protecting a doped silicate glass layer includes: forming a doped silicate glass layer on a substrate in a reaction chamber by plasma-enhanced atomic layer deposition (PEALD) using a first RF power; and forming a non-doped silicate glass layer having a thickness of less than 4 nm on the doped silicate glass layer in the reaction chamber, without breaking vacuum, by plasma-enhanced atomic layer deposition (PEALD) using a second RF power, wherein the second RF power is at least twice the first RF power.

Claims

1. A method for protecting a doped silicate glass layer, comprising:

forming a doped silicate glass layer on a substrate in a reaction chamber by plasma-enhanced atomic layer deposition (PEALD) using a first RF power; and

forming a non-doped silicate glass layer having a thickness of less than 4 nm on the doped silicate glass layer in the reaction chamber, without breaking vacuum, by plasma-enhanced atomic layer deposition (PEALD) using a second RF power,

wherein the second RF power is at least twice the first RF power.

2. The method according to claim 1, wherein the second RF power is at least three times the first RF power.

3. The method according to claim 1, wherein the non-doped silicate glass layer has a thickness of 3 nm or less.

4. The method according to claim 1, wherein the doped silicate glass layer is constituted by borosilicate glass or phosphosilicate glass.

5. The method according to claim 1, wherein the non-doped silicate glass layer is deposited in contact with the doped silicate glass layer.

6. The method according to claim 1, further comprising treating the non-doped silicate glass layer with a plasma without a precursor in the reaction chamber without breaking vacuum.

7. The method according to claim 6, wherein the plasma is an oxygen plasma and/or argon plasma.

8. The method according to claim 1, further comprising, before forming the non-doped silicate glass layer as an upper non-doped silicate glass layer using the second RF power, forming a lower non-doped silicate glass layer on the doped silicate glass layer in the reaction chamber, without breaking vacuum, by plasma-enhanced atomic layer deposition (PEALD) using a third RF power, wherein the thickness of the lower non-doped silicate glass layer is such that the total thickness of the upper non-doped silicate glass layer and the lower non-doped silicate glass layer is less than 4 nm, and the third RF power is lower than the second RF power.

9. The method according to claim 8, wherein the third RF power is equivalent to or lower than the first RF power.

10. The method according to claim 8, wherein the lower non-doped silicate glass layer is deposited in contact with the lower non-doped silicate glass layer which is deposited in contact with the doped silicate glass layer.

11. The method according to claim 1, wherein an alkylaminosilane precursor is supplied from a reservoir to the reaction chamber for the PEALD of the doped silicate glass layer and for the PEALD of the non-doped silicate glass layer.

12. The method according to claim 11, wherein the temperature of the reservoir is higher for the PEALD of the non-doped silicate glass layer than the temperature of the reservoir for the PEALD of the doped silicate glass layer.

13. The method according to claim 8, wherein an alkylaminosilane precursor is supplied from a reservoir to the reaction chamber for the PEALD of the doped silicate glass layer, for the PEALD of the upper non-doped silicate glass layer, and for the PEALD of the lower non-doped silicate glass layer.

14. The method according to claim 13, wherein the temperature of the reservoir is higher for the PEALD of the upper and lower non-doped silicate glass layers than the temperature of the reservoir for the PEALD of the doped silicate glass layer.

15. The method according to claim 1, wherein oxygen gas and a noble gas are continuously supplied to the reaction chamber throughout the PEALD of the doped silicate glass layer and the PEALD of the non-doped silicate glass layer.

16. The method according to claim 7, wherein oxygen gas and a noble gas are continuously supplied to the reaction chamber throughout the PEALD of the doped silicate glass layer, the PEALD of the non-doped silicate glass layer, and the oxygen plasma treatment.

17. The method according to claim 8, wherein oxygen gas and a noble gas are continuously supplied to the reaction chamber throughout the PEALD of the doped silicate glass layer, the PEALD of the lower non-doped silicate glass layer, and the PEALD of the upper non-doped silicate glass layer.

18. The method according to claim 11, wherein the alkylaminosilane is selected from the group consisting of bisdiethylaminosilane (BDEAS), biszimethylaminosilane (BDMAS), hexylethylaminosilane (HEAD), tetraethylaminosilane (TEAS), tert-butylaminosilane (TBAS), bistert-butylaminosilena (BTBAS), bisdimethylaminodimethylaminosilane (BDMADMS), heptametyhlsilazane (HIVIDS), trimethysylyldiethlamine (TMSDEA), trimethylsyledimethlamine (TMSDMA), trimethyltoribinylcycletrisilazane (TMTVCTS), tri strimetylhydroxyamine (TTMSHA), bisdimethylsaminomethylsilane (BDMAMS), and dimetyhlsilyldimethlamine (DMSDMA).

19. The method according to claim 1, further comprising annealing the doped silicate glass layer and the non-doped silicate glass layer to diffuse a dopant contained in the doped silicate glass to the substrate.

20. The method according to claim 1, wherein a thickness of the doped silicate glass layer is 1 nm to 5 nm.