FIN STRUCTURE AND METHOD OF FORMING THE SAME

• US 20130200483A1
• Filed: 02/08/2012
• Published: 08/08/2013
• Est. Priority Date: 02/08/2012
• Status: Abandoned Application

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Tung, Yu-Cheng
• Application Number:
  US13/368,754
• Publication Number:
  US 20130200483A1
• Time in Patent Office: Days
• US Class Current: 257/506
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3085 characterised by their behaviour during the process, e.g. soluble masks, redeposited masks
• CPC Class Codes: H01L 21/76232 of trenches having a shape other than rectangular or V-shape, e.g. rounded corners, oblique or rounded trench walls H01L21/76229 takes precedence
• CPC Class Codes: H01L 29/06 characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
• CPC Class Codes: H01L 29/66818 the channel being thinned after patterning, e.g. sacrificial oxidation on fin
• CPC Class Codes: H01L 29/7853 the body having a non-rectangular crossection

Abstract

A method of forming a fin structure is provided. The method includes forming a hard mask material layer on a substrate, and then patterning the hard mask material layer to form a first hard mask layer. Thereafter, a portion of the substrate is removed to form two trenches, wherein a remaining substrate forms a fin between the trenches. Afterwards, an insulating layer is formed in each trench, wherein the insulating layers expose an upper portion of the fin. Further, the upper portion of the fin is trimmed, so that the trimmed upper portion is narrower than a lower portion of the fin, and a fin structure having an inverse T shape is formed.

Claims

1. A method of forming a fin structure, comprising:

forming a hard mask material layer on a substrate;

patterning the hard mask material layer to form a first hard mask layer;

removing a portion of the substrate to form two trenches, wherein a remaining substrate forms a fin between the trenches;

forming an insulating layer in each trench, wherein the insulating layers expose an upper portion of the fin;

after the insulating layer formed in each trench, tuning the first hard mask layer to form a second hard mask layer, wherein the second hard mask layer exposes a portion of a surface of the fin;

trimming the upper portion of the fin by etching a portion of the fin using the second hard mask layer as a mask, so that the trimmed upper portion is narrower than a lower portion of the fin, and a fin structure having an inverse T shape is formed; and

removing the second hard mask layer.

3. The method of claim 1, further comprising, before the step of removing the second hard mask layer, removing a portion of the fin between the insulating layers, so as to form a recess between the fin and each insulating layer.

4. The method of claim 1, wherein a method of trimming the upper portion of the fin comprises:

performing an oxidation process that at least oxidizes a sidewall of the upper portion of the fin exposed by the first hard mask layer and the insulating layers to form an oxide;

removing the first hard mask layer; and

removing the oxides.

5. The method of claim 4, wherein the oxidation process further comprises oxidizing a portion of the fin between the insulating layers, so that the oxide is formed to extend between the fin and each insulating layer.

6. The method of claim 5, further comprising removing a portion of the insulating layers during the step of removing the oxides, so that remaining insulating layers completely cover a sidewall of the lower portion of the fin.

7. The method of claim 5, further comprising, after the step of removing the oxides, removing a portion of the insulating layers, so as to expose a portion of a sidewall of the lower portion of the fin.

8. The method of claim 4, further comprising removing a portion of the insulating layers during the step of removing the oxides, so as to expose a portion of a sidewall of the lower portion of the fin.

9. The method of claim 1, wherein a method of trimming the upper portion of the fin comprises:

performing an oxidation process that at least oxidizes a sidewall of the upper portion of the fin exposed by the first hard mask layer and the insulating layers to form an oxide;

removing the oxides; and

removing the first hard mask layer.

10. The method of claim 9, wherein the oxidation process further comprises oxidizing a portion of the fin between the insulating layers, so that the oxide is formed to extend between the fin and each insulating layer.

11. The method of claim 10, further comprising removing a portion of the insulating layers during the step of removing the oxides, so that remaining insulating layers completely cover a sidewall of the lower portion of the fin.

12. The method of claim 11, further comprising, after the step of removing the oxides, removing a portion of the insulating layers, so as to expose a portion of a sidewall of the lower portion of the fin.

13. The method of claim 9, further comprising removing a portion of the insulating layers during the step of removing the oxides, so as to expose a portion of a sidewall of the lower portion of the fin.

14. The method of claim 1, further comprising forming an epitaxial layer to cover a surface of the fin exposed by the insulating layers.

2. (canceled)

15-20. -20. (canceled)