IPC분류정보
국가/구분 |
United States(US) Patent
등록
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국제특허분류(IPC7판) |
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출원번호 |
US-0535594
(2009-08-04)
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등록번호 |
US-8372757
(2013-02-12)
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발명자
/ 주소 |
- Mayer, Steven T.
- Webb, Eric
- Porter, David W.
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출원인 / 주소 |
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인용정보 |
피인용 횟수 :
8 인용 특허 :
68 |
초록
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Exposed copper regions on a semiconductor substrate can be etched by a wet etching solution comprising (i) one or more complexing agents selected from the group consisting of bidentate, tridentate, and quadridentate complexing agents; and (ii) an oxidizer, at a pH of between about 5 and 12. In many
Exposed copper regions on a semiconductor substrate can be etched by a wet etching solution comprising (i) one or more complexing agents selected from the group consisting of bidentate, tridentate, and quadridentate complexing agents; and (ii) an oxidizer, at a pH of between about 5 and 12. In many embodiments, the etching is substantially isotropic and occurs without visible formation of insoluble species on the surface of copper. The etching is useful in a number of processes in semiconductor fabrication, including for partial or complete removal of copper overburden, for planarization of copper surfaces, and for forming recesses in copper-filled damascene features. Examples of suitable etching solutions include solutions comprising a diamine (e.g., ethylenediamine) and/or a triamine (e.g., diethylenetriamine) as bidentate and tridentate complexing agents respectively and hydrogen peroxide as an oxidizer. In some embodiments, the etching solutions further include pH adjustors, such as sulfuric acid, aminoacids, and carboxylic acids.
대표청구항
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1. A method of processing a damascene feature on a partially fabricated semiconductor substrate, the method comprising: (a) receiving a semiconductor substrate having a field region and at least one recessed damascene feature formed in the substrate, wherein the substrate is lined with a layer of co
1. A method of processing a damascene feature on a partially fabricated semiconductor substrate, the method comprising: (a) receiving a semiconductor substrate having a field region and at least one recessed damascene feature formed in the substrate, wherein the substrate is lined with a layer of conductive material;(b) completely electrochemically filling the recessed damascene feature with a copper-containing metal and forming a copper-containing overburden over the field region, wherein the overburden comprises a recess over the filled recessed damascene feature, said recess having substantially the same depth as the overburden thickness;(c) continue electrodepositing copper-containing metal over the substrate to deposit additional overburden material over the field region while substantially reducing the aspect ratio of the recess in the overburden, wherein the thickness of additional overburden material deposited over the field region is at least about 50% of the first thickness of the overburden deposited in (b), wherein (c) only partially fills the recessed feature in the overburden; and(d) wet etching the copper-containing overburden to remove at least all additional overburden deposited in (c) by contacting the substrate with an isotropic wet etching solution, said solution comprising a complexing agent and an oxidizing agent and having a pH in the range of between about 5 and 12, wherein wet etching further reduces the aspect ratio of the recessed feature. 2. The method of claim 1, wherein the thickness of overburden deposited in (b) is less than about 50% of the width of the damascene feature and wherein the amount of overburden removed in (d) is at least about 75% of the total thickness of the overburden deposited in (b) and (c). 3. The method of claim 1, wherein the thickness of additional overburden deposited in (c) is at least about 100% of the thickness of overburden deposited in (b). 4. The method of claim 1, wherein the depth of the recessed damascene feature is at least about 5 μm, and wherein the depth of the recessed damascene feature is at least two times greater than its width. 5. The method of claim 1, wherein wet etching in (d) substantially removes all of the copper-containing overburden. 6. The method of claim 1, wherein wet etching in (d) partially removes the copper containing overburden, wherein the method further comprises removing the remaining overburden and an underlying diffusion barrier layer using chemical mechanical polishing (CMP). 7. The method of claim 1, further comprising: after (d) removing a diffusion barrier layer by wet chemical etching. 8. The method of claim 1, wherein (d) comprises spraying the isotropic wet etching solution from at least two nozzles, wherein at least one parameter selected from the group consisting of (i) nozzle position with respect to the wafer; (ii) time of etchant delivery; (iii) composition of etchant delivered from the nozzles; (iv) flow of quenching solution delivered from at least one nozzle; (v) flow rate of the etchant from the nozzles; (vi) concentration of at least one component in the etchant delivered from the nozzles; and (vii) shape of flow pattern delivered from the at least two nozzles is different for at least two nozzles or is modulated during the etching process. 9. The method of claim 1, wherein the etching solution comprises a diamine and an aminoacid, or a triamine and an aminoacid. 10. The method of claim 1, wherein (d) removes at least about a 1 um thick layer of copper-containing metal. 11. The method of claim 1, wherein the concentration of the complexing agent is between about 0.01 M and 6 M; the concentration of the oxidizer is between about 0.2 M and 12 M, and wherein the molar ratio of an oxidizer to complexing agent of at least about 2.5:1. 12. The method of claim 1, wherein the recessed damascene feature is a through silicon via (TSV). 13. The method of claim 1, wherein during electrodeposition performed in (b) or (c), the electrodeposition conditions are changed in order to reduce the aspect ratio of the recessed feature in the overburden, wherein the change in the electrodeposition conditions comprises at least one of: (i) reducing the substrate rotation rate;(ii) increasing the current density provided to the substrate; and(iii) contacting the substrate with a first plating solution followed by a second plating solution having a different chemistry than the first plating solution, wherein the chemistry of the second plating solution is configured for reducing the aspect ratio of the recessed feature in the overburden. 14. The method of claim 13, wherein the electroplating conditions are changed to reduce the aspect ratio of the recess in the overburden, while the damascene feature is not yet completely filled in (b). 15. The method of claim 1, wherein the wet etching solution comprises ethylenediamine and hydrogen peroxide, and wherein the solution has a pH of between about 7 and 10.5. 16. The method of claim 15, wherein the solution further comprises a pH adjustor selected from the group consisting of sulfuric acid, glycine, acetic acid, citric acid, methanesulphonic acid, oxalic acid and glyoxilic acid. 17. The method of claim 1, wherein the complexing agent is selected from the group consisting of bidentate, tridentate and quadridentate complexing agents, and mixtures thereof. 18. The method of claim 17, wherein the complexing agent is selected from the group consisting of an aminoacid, a diamine, a triamine, and a tetramine, and mixtures thereof. 19. The method of claim 17, wherein the complexing agent is selected from the group consisting of ethylenediamine and diethylenetriamine. 20. A method of processing a damascene feature on a partially fabricated semiconductor substrate, the method comprising: (a) receiving a semiconductor substrate having a field region and at least one recessed damascene feature formed in the substrate, wherein the substrate is lined with a layer of conductive material;(b) completely electrochemically filling the recessed damascene feature with a copper-containing metal and forming a copper-containing overburden over the field region, wherein the overburden comprises a recess over the filled recessed damascene feature, said recess having substantially the same depth as the overburden thickness;(c) continue electrodepo siting copper-containing metal over the substrate to deposit additional overburden material over the field region while substantially reducing the aspect ratio of the recess in the overburden, wherein the thickness of additional overburden material deposited over the field region is at least about 50% of the first thickness of the overburden deposited in (b); and(d) wet etching the copper-containing overburden to remove at least all additional overburden deposited in (c) by contacting the substrate with an isotropic wet etching solution, said solution comprising a complexing agent and an oxidizing agent and having a pH in the range of between about 5 and 12, wherein wet etching further reduces the aspect ratio of the recessed feature, and wherein the concentration of the complexing agent is between about 0.01M and 6M; the concentration of the oxidizer is between about 0.2M and 12 M, and wherein the molar ratio of an oxidizer to complexing agent of at least about 2.5:1. 21. The method of claim 20, wherein the damascene feature is a through silicon via (TSV). 22. The method of claim 20, wherein (c) forms a protrusion over the filled recessed feature on the overburden. 23. The method of claim 20, wherein (d) comprises spraying the isotropic wet etching solution from at least two nozzles, wherein at least one parameter selected from the group consisting of (i) nozzle position with respect to the wafer; (ii) time of etchant delivery; (iii) composition of etchant delivered from the nozzles; (iv) flow of quenching solution delivered from at least one nozzle; (v) flow rate of the etchant from the nozzles; (vi) concentration of at least one component in the etchant delivered from the nozzles; and (vii) shape of flow pattern delivered from the at least two nozzles is different for at least two nozzles or is modulated during the etching process. 24. The method of claim 20, wherein during electrodeposition performed in (b) or (c), the electrodeposition conditions are changed in order to reduce the aspect ratio of the recessed feature in the overburden, wherein the change in the electrodeposition conditions comprises at least one of: (i) reducing the substrate rotation rate;(ii) increasing the current density provided to the substrate; and(iii) contacting the substrate with a first plating solution followed by a second plating solution having a different chemistry than the first plating solution, wherein the chemistry of the second plating solution is configured for reducing the aspect ratio of the recessed feature in the overburden. 25. The method of claim 20, wherein the thickness of overburden deposited in (b) is less than about 50% of the width of the damascene feature and wherein the amount of overburden removed in (d) is at least about 75% of the total thickness of the overburden deposited in (b) and (c). 26. The method of claim 20, wherein the depth of the recessed damascene feature is at least about 5 μm, and wherein the depth of the recessed damascene feature is at least two times greater than its width. 27. The method of claim 20, wherein wet etching in (d) substantially removes all of the copper-containing overburden. 28. The method of claim 20, wherein the wet etching solution comprises ethylenediamine and hydrogen peroxide, and wherein the wet etching solution has a pH of between about 7 and 10.5. 29. The method of claim 28, wherein the solution further comprises a pH adjustor selected from the group consisting of sulfuric acid, glycine, acetic acid, citric acid, methanesulphonic acid, oxalic acid and glyoxilic acid.
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