Methods of Etching Trenches Into Silicon of a Semiconductor Substrate, Methods of Forming Trench Isolation in Silicon of a Semiconductor Substrate, and Methods of Forming a Plurality of Diodes

• US 20100178748A1
• Filed: 03/17/2010
• Published: 07/15/2010
• Est. Priority Date: 12/03/2007
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Subramanian, Krupakar M.
• Granted Patent: US 8,252,658 B2
• Time in Patent Office: Days
• US Class Current: 438/424
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/3083 characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 27/0814 Diodes only
• CPC Class Codes: H01L 29/66136 PN junction diodes
• CPC Class Codes: H01L 29/8613 Mesa PN junction diodes

Abstract

A method of etching trenches into silicon of a semiconductor substrate includes forming a mask over silicon of a semiconductor substrate, with the mask comprising trenches formed there-through. Plasma etching is conducted to form trenches into the silicon of the semiconductor substrate using the mask. In one embodiment, the plasma etching includes forming an etching plasma using precursor gases which include SF₆, an oxygen-containing compound, and a nitrogen-containing compound. In one embodiment, the plasma etching includes an etching plasma which includes a sulfur-containing component, an oxygen-containing component, and NF_x.

Claims

1. A method of etching trenches into silicon of a semiconductor substrate, comprising:

forming a mask over silicon of a semiconductor substrate, the mask comprising trenches formed there-through; and

plasma etching trenches into the silicon of the semiconductor substrate using the mask, the plasma etching comprising forming an etching plasma using precursor gases comprising SF₆, an oxygen-containing compound, and a nitrogen-containing compound.

2. The method of claim 1 wherein the oxygen-containing compound and the nitrogen-containing compound comprise different compounds.

3. The method of claim 1 wherein the oxygen-containing compound and the nitrogen-containing compound comprise the same compound.

4. The method of claim 3 wherein the same compound comprises NO_x.

5. The method of claim 1 wherein the precursor gases comprise HBr.

6. The method of claim 1 wherein the mask comprises an outermost hardmask layer during at least a latter portion of the plasma etching into the silicon, said outermost hardmask layer being void of carbon.

7. The method of claim 1 wherein the nitrogen-comprising compound comprises N₂.

8. The method of claim 7 wherein the precursor gases comprise HBr.

9. The method of claim 1 wherein the precursor gases comprise two oxygen-containing compounds, one of the oxygen compounds being void of nitrogen, another of the oxygen-containing compounds comprising the nitrogen-containing compound.

10. The method of claim 9 wherein the one comprises O₂ and the another comprise NO_x.

11. A method of etching trenches into silicon of a semiconductor substrate, comprising:

forming a mask over silicon of a semiconductor substrate, the mask comprising trenches formed there-through; and

plasma etching trenches into the silicon of the semiconductor substrate using the mask, the plasma etching comprising an etching plasma comprising a sulfur-containing component, an oxygen-containing component, and NF_x.

12. The method of claim 11 the sulfur of the sulfur-containing component is formed from a precursor gas comprising SF₆.

13. The method of claim 11 wherein the oxygen of the oxygen-containing component is formed from a precursor gas comprising O₂, and the nitrogen of the NF_x is formed from a precursor gas compound which is void of oxygen.

14. The method of claim 11 wherein the oxygen of the oxygen-containing component and the nitrogen of the NF_x are formed from a precursor gas comprising NO_x.

15-23. -23. (canceled)

24. A method of forming a plurality of diodes, comprising:

forming a first mask over silicon of a semiconductor substrate, the first mask comprising first trenches formed there-through running in a first major direction over the substrate, the first mask comprising a hardmask layer;

plasma etching first trenches into the silicon of the semiconductor substrate using the first mask, the plasma etching of the first trenches into the silicon comprising forming an etching plasma using precursor gases comprising SF₆, an oxygen-containing compound, and a nitrogen-containing compound;

forming a second mask over the first trenches, the second mask comprising second trenches formed there-through running in a second major direction over the substrate which is orthogonal to the first major direction, the second mask comprising the hardmask layer of the first mask, the second trenches extending through the hardmask layer of the first mask;

plasma etching second trenches into the silicon of the semiconductor substrate using the second mask, the plasma etching of the second trenches into the silicon comprising forming an etching plasma using precursor gases comprising SF₆, an oxygen-containing compound, and a nitrogen-containing compound, the plasma etching of the second trenches into the silicon forming spaced silicon-comprising mesas; and

providing individual diodes on individual of the mesas and depositing insulative material to be received about the spaced silicon-comprising mesas.

25. The method of claim 24 wherein the individual diodes comprise a p-type silicon-comprising region and an n-type silicon-comprising region.

26. The method of claim 24 wherein the oxygen-containing compound and the nitrogen-containing compound comprise different compounds in each of the plasma etchings of the first and second trenches.

27. The method of claim 24 wherein the oxygen-containing compound and the nitrogen-containing compound comprise the same compound in each of the plasma etchings of the first and second trenches.

28. The method of claim 27 wherein the same compound comprises NO_x.

29. The method of claim 24 wherein the precursor gases comprise HBr in each of the plasma etchings of the first and second trenches.