Selective growth of SiO2 on dielectric surfaces in the presence of copper

• US 10,460,930 B2
• Filed: 11/22/2017
• Issued: 10/29/2019
• Est. Priority Date: 11/22/2017
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Hausmann, Dennis M., Fox, Alexander R., Lawlor, Colleen
• Primary Examiner(s): Maruf, Sheikh
• Application Number:
  US15/821,590
• Publication Number:
  US 20190157076A1
• Time in Patent Office: 706 Days
• Field of Search: 438771
• CPC Class Codes: C23C 16/04 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• 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 21/02233 of the semiconductor substrate or a semiconductor layer
• 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 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/32 using masks
• CPC Class Codes: H01L 21/321 After treatment
• CPC Class Codes: H01L 21/67207 comprising a chamber adapted to a particular process
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76829 : characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76883 : Post-treatment or after-treatment of the conductive material
• CPC Class Codes: H01L 21/76897 : Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665

Abstract

Methods and apparatuses for selectively depositing silicon oxide on dielectric surfaces relative to a metal-containing surface such as copper are provided. Methods involve exposing a substrate having dielectric and copper surfaces to a copper-blocking reagent such as an alkyl thiol to selectively adsorb to the copper surface, exposing the substrate to a silicon-containing precursor for depositing silicon oxide, exposing the substrate to a weak oxidant gas and igniting a plasma to convert the adsorb silicon-containing precursor to form silicon oxide, and exposing the substrate to a reducing agent to reduce any oxidized copper from exposure to the weak oxidant gas.

Claims

1. A method of selectively depositing silicon oxide on a dielectric material relative to copper on a substrate, the method comprising:

(a) providing the substrate comprising the dielectric material and exposed copper metal surface;

(b) prior to depositing the silicon oxide, exposing the substrate to a copper-blocking reagent to selectively adsorb onto the exposed copper metal surface;

(c) exposing the substrate to a silicon-containing precursor to adsorb the silicon-containing precursor onto the dielectric material;

(d) exposing the substrate to an oxidizing plasma generated in an environment comprising a weak oxidant to convert the adsorbed silicon-containing precursors to silicon oxide; and

(e) exposing the substrate to a reducing agent to reduce the exposed copper metal surface.

2. The method of claim 1, wherein the copper-blocking reagent comprises sulfur.

3. The method of claim 1, wherein the copper-blocking reagent is an alkyl thiol.

4. The method of claim 3, wherein the copper-blocking reagent is selected from the group consisting of ethane thiol and butane thiol.

5. The method of claim 1, wherein the copper-blocking reagent is an alkyl thiol having a chemical formula SH(CH₂)_nCH₃ whereby n is an integer between and including 2 and 12.

6. The method of claim 1, wherein the silicon-containing precursor is an aminosilane.

7. The method of claim 1, wherein the silicon-containing precursor is selected from the group consisting of N-(diethylaminosilyl)-N-ethylethanamine, bis(diethylamino)silane (BDEAS), diisopropylamino silane (DiPAS), diisobutylamino silane (DiBAS), bis(tert-butylamino)silane (BTBAS), and tris(dimethylamino)silane (TDMAS).

8. The method of claim 1, wherein the weak oxidant is selected from the group consisting of carbon dioxide, nitrous oxide, ozone, plasmas thereof, and water.

9. The method of claim 1, wherein the reducing agent is selected from the group consisting of hydrogen gas, hydrogen plasma, hydrazine gas, hydrazine plasma, ammonia gas, ammonia plasma, alcohols, and aldehydes.

10. The method of claim 1, wherein silicon oxide is deposited at a temperature between about 70°

C. and about 200°

C.

11. The method of claim 1, further comprising, prior to exposing the substrate to the copper-blocking reagent, introducing a second reducing agent to reduce the exposed copper metal surface.

12. The method of claim 11, wherein the second reducing agent is selected from the group consisting of hydrogen gas, hydrogen plasma, hydrazine gas, hydrazine plasma, ammonia gas, ammonia plasma, alcohols, and aldehydes.

13. The method of claim 1, wherein the dielectric material is selected from the group consisting of silicon dioxide, aluminum oxide, silicon oxycarbides, silicon carbonitrides, and silicon oxycarbonitrides.

14. The method of claim 1, further comprising repeating operations (b)-(e) in two or more cycles.

15. The method of claim 1, wherein (c) is self-limiting.

16. The method of claim 1, wherein the copper-blocking reagent preferentially adsorbs to the exposed copper metal surface to block subsequent deposition of the silicon oxide on the exposed copper metal surface.

17. A method of selectively depositing silicon oxide on a dielectric material relative to a metal-containing surface on a substrate, the method comprising:

(a) providing the substrate comprising the dielectric material and exposed metal-containing surface;

(b) prior to depositing the silicon oxide, exposing the substrate to a metal-blocking reagent to selectively adsorb onto the exposed metal-containing surface;

(c) exposing the substrate to a silicon-containing precursor to adsorb the silicon-containing precursor onto the dielectric material;

(d) exposing the substrate to an oxidizing plasma generated in an environment comprising a weak oxidant to convert the adsorbed silicon-containing precursors to silicon oxide; and

(e) exposing the substrate to a reducing agent to reduce the exposed metal-containing surface.

18. The method of claim 17, wherein the exposed metal-containing surface comprises copper.

19. The method of claim 17, wherein the exposed metal-containing surface comprises ruthenium.

20. The method of claim 17, wherein the exposed metal-containing surface comprises a material selected from the group consisting of copper metal, copper oxide, ruthenium metal, and ruthenium oxide.