Silicon nitride film forming method, silicon nitride film forming system and silicon nitride film forming system precleaning method

• US 20020106909A1
• Filed: 02/06/2002
• Published: 08/08/2002
• Est. Priority Date: 02/07/2001
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Endo, Atsushi, Nishita, Tatsuo, Kato, Hitoshi, Kumagai, Takeshi, Fukushima, Kohei
• Granted Patent: US 6,844,273 B2
• Time in Patent Office: Days
• US Class Current: 438/791
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/4405 Cleaning of reactor or parts inside the reactor by using reactive gases
• CPC Class Codes: C23C 16/4412 Details relating to the exhausts, e.g. pumps, filters, scrubbers, particle traps
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: Y10S 438/905 Cleaning of reaction chamber

Abstract

A thermal processing system (1) includes a reaction vessel (2) capable of forming a silicon nitride film on semiconductor wafers (10) through interaction between hexachlorodisilane and ammonia, and an exhaust pipe (16) connected to the reaction vessel (2). The reaction vessel 2 is heated at a temperature in the range of 500 to 900° C. and the exhaust pipe (16) is heated at 100° C. before disassembling and cleaning the exhaust pipe 16. Ammonia is supplied through a process gas supply pipe (13) into the reaction vessel (2), and the ammonia is discharged from the reaction vessel (2) into the exhaust pipe (16).

Claims

1. A silicon nitride film forming system comprising:

a reaction vessel capable of holding a workpiece therein and provided with a first heating unit for heating the workpiece at a process temperature;

a gas supply pipe for carrying hexachlorodisilane and ammonia into the reaction vessel;

an exhaust pipe connected to the reaction vessel and provided with a second heating unit capable of heating the exhaust pipe at a temperature high enough to gasify an ammonium chloride;

an exhaust system capable of exhausting a gas from the reaction vessel through the exhaust pipe and of setting a pressure in an interior of the reaction vessel at a predetermined pressure; and

a control unit for controlling the exhaust system to set the pressure in the interior of the reaction vessel at the predetermined pressure and for controlling the supply of hexachlorodisilane and ammonia through the gas supply pipes into the reaction vessel;

wherein the control unit is capable of controlling the first heating unit to set a temperature of the interior of the reaction vessel at a temperature capable of causing the thermal decomposition of hexachlorodisilane and of controlling the second heating unit to heat the exhaust pipe at a temperature capable of gasifying the ammonium chloride.

2. The silicon nitride film forming system according to claim 1, wherein

the control unit controls the second heating unit so as to heat the exhaust pipe at 150°

C. or above.

3. The silicon nitride film forming system according to claim 2, wherein

the control unit controls the second heating unit so as to heat the exhaust pipe at a temperature in the range of 190 to 200°

C.

4. A silicon nitride film forming method comprising the steps of:

placing a workpiece in a reaction vessel;

forming a silicon nitride film on the workpiece by supplying hexachlorodisilane and ammonia into the reaction vessel; and

exhausting gas from the reaction vessel through an exhaust pipe connected to the reaction vessel;

wherein a reaction chamber defined by the reaction vessel is heated at a temperature capable of decomposing hexachlorodisilane by thermal decomposition when supplying hexachlorodisilane and ammonia into the reaction vessel, and the exhaust pipe is heated at a temperature capable of gasifying an ammonium chloride when discharging the gases from the reaction vessel through the exhaust pipe.

5. The silicon nitride film forming method according to claim 4, wherein

the exhaust pipe is heated at 150°

C. or above.

6. The silicon nitride film forming method according to claim 5, wherein

the exhaust pipe is heated at a temperature in the range of 190 to 200°

C.

7. A precleaning method of precleaning a silicon nitride film forming system including a reaction vessel into which hexachlorodisilane and ammonia are supplied to form a silicon nitride film on a workpiece, and an exhaust pipe connected to the reaction vessel, said precleaning method comprising the steps of:

supplying ammonia into the reaction vessel; and

discharging ammonia from the reaction vessel into the exhaust pipe.

8. The precleaning method according to claim 7, wherein

the reaction chamber is heated at a temperature in the range of 500 to 900°

C., while ammonia is supplied into the reaction vessel.

9. The precleaning method according to claim 7, wherein

the exhaust pipe is heated at 100°

C. or above, while ammonia is discharged into the exhaust pipe.

10. The precleaning method according to claim 7, wherein

a pressure within an interior of the exhaust pipe is set at pressures in the range of 665 to 66500 Pa, while ammonia is discharged into the exhaust pipe.

11. The precleaning method according to claim 7 further:

comprising a step of supplying an inert gas through the reaction vessel into the exhaust pipe, before the step of supplying ammonia into the reaction vessel.

12. The precleaning method according to claim 7 further:

comprising a step of supplying an inert gas through the reaction vessel into the exhaust pipe, after the step of supplying ammonia through the reaction vessel into the exhaust pipe.