PROCESS FOR ETCHING SILICON WITH SELECTIVITY TO SILICON-GERMANIUM

• US 20120129354A1
• Filed: 11/22/2010
• Published: 05/24/2012
• Est. Priority Date: 11/22/2010
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: LUONG, Vinh
• Granted Patent: US 8,389,416 B2
• Time in Patent Office: Days
• US Class Current: 438/714
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 29/0673 oriented parallel to a substrate

Abstract

A method for performing a selective etching process is described. The method includes preparing a substrate having a silicon layer (Si) and a silicon-germanium (SiGe_x) layer, and selectively etching the silicon layer relative to the silicon-germanium layer using a dry plasma etching process.

Claims

2-1. The method of claim 1, wherein said process composition consists of HBr and He.

15. A method for preparing a silicon-germanium nano-wire, comprising:

preparing a film stack on a substrate having alternating layers of silicon (Si) and silicon-germanium (SiGe_x);

transferring a pattern through a silicon (Si) layer in said alternating layers of silicon (Si) and silicon-germanium (SiGe_x) to expose a sidewall of said silicon (Si) layer;

transferring said pattern through a silicon-germanium (SiGe_x) layer in said alternating layers of silicon (Si) and silicon-germanium (SiGe_x) to expose a sidewall of said silicon-germanium (SiGe_x) layer; and

laterally etching said sidewall of said silicon (Si) layer by exposing said film stack to a dry plasma etching process having a process composition containing as incipient ingredients HBr and optionally He,

wherein said dry plasma etching process achieves an etch selectivity between said silicon (Si) layer and said silicon-germanium (SiGe_x) layer greater than unity.

16. The method of claim 15, wherein said dry plasma etching process achieves an etch selectivity between said silicon (Si) layer and said silicon-germanium (SiGe_x) layer greater than or equal to two.

17. The method of claim 15, wherein said process composition contains HBr and He.

18. The method of claim 15, wherein said process composition consists of HBr and He.

19. The method of claim 15, wherein said transferring said pattern through said silicon (Si) layer and said silicon-germanium (SiGe_x) layer creates a fin structure extending between opposing buttress structures located at distal ends of said fin structure.

20. The method of claim 19, wherein said laterally etching said silicon (Si) layer removes said silicon (Si) layer from said fin structure and releases a silicon-germanium (SiGe_x) layer bridge.