Methods for manufacturing semiconductor devices

Patent metadata

Field	Value
Publication number	US-9418835-B2
Application number	US-201514662963-A
Country	US
Kind code	B2
Filing date	Mar 19, 2015
Priority date	Nov 25, 2014
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

The present disclosure provides a method of manufacturing a semiconductor device having silicon nitride with a tensile stress, the method comprising: c1) introducing and pre-stabilizing NH 3 gas and N 2 gas; c2) introducing silane; c3) igniting the gases by a radio-frequency source; c4) depositing SiN; and c5) processing the SiN by using a nitrogen ion implantation. According to the present disclosure, the nitrogen content in the SiN film can be enhanced by the nitrogen ion implantation and impinging, thereby increasing the density of the film. In this way, the acid resistance of the SiN with tensile stress is enhanced, so that the SiN with tensile stress may be integrated in a dual-strained liner of a gate-last process, so as to effectively improve the properties and reliability of the device.

First claim

We claim:

1. A method of manufacturing silicon nitride with a tensile stress for a semiconductor device, the method comprising:
c1) introducing and pre-stabilizing NH 3 gas and N 2 gas into a chamber of a deposition device, to enable the NH 3 gas and N 2 gas in the chamber to be diffused uniformly and to maintain a stable pressure in the chamber;
c2) introducing silane into the chamber;
c3) igniting the mixed gases of NH 3 , N 2 and silane in the chamber using a radio-frequency source;
c4) after c1)-c3) are performed in sequence, depositing SiN with a tensile stress on a wafer, wherein c1)-c4) performed in sequence is a deposition cycle; and
c5) processing the SiN with a nitrogen ion implantation process.

2. The method according to claim 1 , wherein in c1), a flow rate of the NH 3 gas is about 80 sccm and a flow rate of the N 2 gas is about 4000 sccm.

3. The method according to claim 1 , wherein in c2), a flow rate of silane is about 20 sccm.

4. The method according to claim 1 , wherein c3), comprises starting a radio-frequency source of 40 W for 5 seconds while maintaining flow rates of the gases in c1) and c2).

5. The method according to claim 1 , wherein c4) is performed for about 1.5 seconds, so that a thickness of the SiN deposited on the wafer is about 25 Å.

6. The method according to claim 1 , wherein during performing c1)-c4), the pressure in the chamber is stably controlled at about 6 Torr.

7. The method according to claim 1 , wherein c5) further comprises (1) closing valves for the NH 3 gas and silane and keeping a valve for the N 2 gas open to continuously introduce N 2 up to about 4000 sccm in the same chamber of the deposition device, and starting a RF source of about 40 W to excite nitrogen plasma to impinge a surface of the SiN; and/or (2) transferring the wafer with the SiN deposited thereon to a low-energy ion implantation chamber, and then implanting nitrogen ions into the SiN.

8. The method according to claim 1 , wherein c1)-c5) are performed repeatedly for many times, wherein c5) is performed after each deposition cycle.

9. The method according to claim 1 , wherein c1)-c5) are performed repeatedly for many times, wherein c5) is performed only after one or more selected deposition cycles.

10. The method according to claim 1 , further comprising, before c1), cleaning and seasoning the chamber of the deposition device which consumes about 120 seconds, and loading the wafer, which consumes about 5 seconds, wherein the deposition device is a dual-frequency capacitive coupling flat-plate type of plasma enhanced chemical vapor deposition (PECVD) device and a background vacuum in the chamber of the deposition device is less than or equal to about 30 mTorr.

Assignees

• Inst Of Microelectronics Cas

Inventors

• Wang Guilei
• Liu Jinbiao
• Li Junfeng

Classifications

• H10P30/20

  into semiconductor materials, e.g. for doping · CPC title

• H10P14/6682

  the compound being a silane, e.g. disilane, methylsilane or chlorosilane · CPC title

• H10P14/6532

  by exposure to a plasma · CPC title

• H10P14/6524

  the substance being nitrogen · CPC title

• H10P14/6512

  by exposure to a gas or vapour · CPC title