JP4964908B2 - Cleaning the reaction tube - Google Patents

Description

  The present invention relates to improvement of a semiconductor manufacturing apparatus having a vertical furnace, in particular, a furnace port portion for performing high temperature processing such as high temperature oxidation processing.

  Referring to FIG. 4, a conventional vertical furnace for high-temperature oxidation treatment of a semiconductor manufacturing apparatus will be described. FIG. 4 shows a furnace port portion of the vertical furnace.

  A cylindrical heater unit 1 whose upper end is closed is erected on a heater base 3 via a heat insulating material 2, and below the heater base 3 is a support block 4 attached to the lower surface of the heater unit 1. A reaction tube base 5 is provided. The reaction tube base 5 is provided with a flange adapter 6, and a cylindrical reaction tube 7 whose upper end is closed is erected on the flange adapter 6. The lower end of the reaction tube 7 extends below the heater base 3. A boat (not shown) is inserted into the reaction tube 7, and the boat is placed on a boat cradle 9 through a boat cap 8.

  A furnace port heat insulating material 10 is provided so as to close a gap between the heat insulating material 2 and the vicinity of the lower end of the reaction tube 7, and a heat insulating cloth 11 is wound around the lower end portion of the reaction tube 7. The temperature drop is suppressed.

  Since quartz has a problem in heat resistance at a high temperature of 1200 ° C. or higher, silicon carbide (SiC) is used. Even in a vertical furnace of a conventional semiconductor manufacturing apparatus, the reaction tube 7 is made of silicon carbide, and the flange adapter 6 is made of quartz.

  As described above, since the lower end portion of the reaction tube 7 protrudes downward from the heating region surrounded by the heater unit 1, a large temperature difference occurs between the lower end portion and the portion in the heating region. When a flange is provided at the lower end of the reaction tube 7, thermal stress due to the temperature difference is concentrated on the flange portion. Further, since silicon carbide, which is a material for the reaction tube 7, is a brittle material, it is damaged when a large thermal stress is generated. For this reason, a flange cannot be provided at the lower end of the reaction tube 7. In the conventional example shown in FIG. 4, no flange is formed at the lower end of the reaction tube 7. Further, no sealing material is provided between the reaction tube 7 and the flange adapter 6 due to heat resistance, and the seal between the reaction tube 7 and the flange adapter 6 reacts with the lower end surface of the reaction tube 7. It is only surface contact with the upper end surface of the pipe flange adapter 6.

  Therefore, if hydrogen chloride (HCl) gas is flowed into the reaction tube 7 as a cleaning gas, the HCl gas leaks from the contact surface between the reaction tube 7 and the flange adapter 6 and corrodes the metal part of the apparatus. There was a problem.

  In view of such circumstances, the present invention prevents the cleaning gas from leaking from the reaction furnace in the vertical furnace for high-temperature treatment, and enables the use of HCl gas as the cleaning gas.

In the present invention , a flange is formed at the lower end of the reaction tube, a seal groove is formed between the upper flange of the flange adapter and the flange, the flange and the upper flange are overlapped, and a seal gas is supplied to the seal groove. Further, the present invention relates to a method for cleaning a reaction tube comprising a step of making the pressure in the seal groove higher than the pressure inside and outside the reaction tube and a step of introducing a cleaning gas into the reaction tube .

According to the present invention, a flange is formed at the lower end of the reaction tube, a seal groove is formed between the upper flange of the flange adapter and the flange, the flange and the upper flange are overlapped, and seal gas is supplied to the seal groove. And supplying a pressure in the seal groove higher than the pressure inside and outside the reaction tube and a step of introducing a cleaning gas into the reaction tube. Excellent effect of preventing gas leakage from inside the tube.

It is a fragmentary sectional view of the furnace port part which shows the Example of this invention, and is AA-B sectional drawing of FIG. It is a fragmentary sectional view of the furnace port part which shows the Example of this invention, and is COD sectional drawing of FIG. It is a plane sectional view of a furnace mouth part showing an example of the present invention, and is an EE sectional view of FIG. It is sectional drawing of the furnace port part of a prior art example.

Hereinafter, an embodiment of the present invention with reference to the drawings.

  1 to 3, the same components as those shown in FIG. 4 are denoted by the same reference numerals.

  A quartz flange adapter 13 having an upper flange 13 a and a lower flange 13 b on the upper and lower sides is mounted on the reaction tube base 5. The upper end of the upper flange 13a of the flange adapter 13 coincides with or substantially coincides with the lower end of the heating area of the heater unit 1, and the flange 7a of the reaction tube 7 made of silicon carbide is superposed on the upper flange 13a. 7 is erected. A heat insulating cloth 11 is wound around a portion of the flange adapter 13 exposed below the heater base 3.

A reaction gas introduction port 14 is provided through the heat insulating cloth 11 and the cylindrical side wall of the flange adapter 13. The reaction gas introduction port 14 is closed at the tip, and a reaction gas introduction nozzle 15 communicates with the upper surface of the tip. The reaction gas introduction nozzle 15 extends to the upper end of the reaction tube 7 and introduces the reaction gas from the upper end of the reaction gas introduction port 14 and an introduction hole (not shown) drilled at an appropriate location. . An exhaust port 16 communicates with the cylindrical side wall of the flange adapter 13, and an outer end projects through the heat insulating cloth 11 and protrudes to the outside.

  An air supply pipe 17 is connected to the reaction gas introduction port 14, an O-ring 18 is interposed between the flange of the reaction gas introduction port 14 and the flange of the air supply pipe 17, and both flanges are connected by a flange clamp 19. . An exhaust pipe 20 is connected to the exhaust port 16, an O-ring 18 is interposed between the flange of the exhaust port 16 and the flange of the exhaust pipe 20, and both flanges are coupled by a flange clamp 19.

  A seal gas introduction port 21 is fixed at a position where it does not interfere with the reaction gas introduction port 14 and the exhaust port 16. The seal gas introduction port 21 and a seal gas source (not shown) are connected by a pipe 22. Also, a seal groove 23 is formed on the upper surface of the upper flange 13a, the seal groove 23 and the seal gas introduction port 21 are communicated with each other by an air supply communication pipe 24, and the seal groove 23 and the exhaust port 16 are exhausted. The communication pipe 25 communicates.

  An L-shaped nitrogen gas purge nozzle 26 and a gas detection nozzle 27 which are inserted from the peripheral surface of the heat insulation cloth 11 and protrude from the upper end surface of the heat insulation cloth 11 are provided, respectively. The nitrogen gas purge nozzle 26 serves as a nitrogen gas supply source (not shown). The gas detection nozzle 27 is connected to a gas detector (not shown).

  In the figure, 28 is an O-ring that seals between the flange of the boat cap 8 and the lower flange 13b, 29 is a cooling pipe embedded in the lower surface of the boat cradle 9 to cool the O-ring 28, and 30 This is a nozzle for supplying and discharging cooling water to and from the cooling passage 32 formed in the flange presser 31 for fixing the lower flange 13b.

  The operation will be described below.

  In a state heated by the heater unit 1, a wafer is loaded into a boat (not shown), the boat is loaded into the reaction tube 7, and the reaction is performed through the air supply pipe 17, the reaction gas introduction port 14, and the reaction gas introduction nozzle 15. A reactive gas is introduced into the tube 7 and a required process, for example, an oxidation process is performed on the wafer. The treated gas is discharged through the exhaust port 16 and the exhaust pipe 20. The processed wafer is pulled out together with a boat (not shown).

  Next, when cleaning the inside of the reaction tube 7 with HCl gas, a boat on which no wafer is loaded is loaded into the reaction tube 7, and the air supply pipe 17, the reaction gas introduction port 14, the reaction gas introduction nozzle 15. Then, HCl gas is introduced into the reaction tube 7, and the HCl gas is further discharged through the exhaust port 16 and the exhaust pipe 20.

  A seal gas, such as nitrogen gas, is supplied to the seal groove 23 through the pipe 22 and the air supply communication pipe 24. The pressure in the seal groove 23 is set higher than the pressure inside and outside the reaction tube 7, and the HCl gas in the reaction tube 7 is sealed from leaking outside between the upper flange 13 a and the flange of the reaction tube 7. Since the gas in the seal groove 23 is exhausted to the exhaust port 16 through the exhaust communication pipe 25, even if there is a leak of HCl gas from the inside of the reaction pipe to the seal groove 23, the gas is diluted with nitrogen gas. Is discharged to the exhaust port 16.

  Further, nitrogen gas is supplied from the nitrogen gas purge nozzle 26 to the vicinity of the upper flange 13a. The vicinity of the upper flange 13a is diluted with nitrogen gas, and the leak of HCl gas is monitored by the gas detection nozzle 27. If there is a leak of HCl gas, a gas detector (not shown) immediately detects the leak of HCl gas via the gas detection nozzle 27 and activates an alarm or feeds back to the control device to supply the HCl gas in the reaction tube 7. Take measures such as stopping the supply.

As described above, high temperature (1200 ° C.) treatment is performed in the oxidation furnace or diffusion furnace, and the temperature of the furnace opening is also high. Coincides with the lower end lower end of the heater unit 1 of the reaction tube 7, or has substantially coincide, large temperature in the flange near even to form a flange 7a to the reaction tube 7 the lower end of the silicon carbide as in this embodiment There is no difference. Therefore, the flange 7a of the reaction tube 7 is not damaged by thermal stress. Furthermore, since the quartz flange adapter 13 has no portion included in the heating region in the heater unit 1, heat resistance does not become a problem.

  Thus, the apparatus can be safely cleaned using HCl gas in a vertical furnace having a high furnace port portion.

  The purge of nitrogen gas by the nitrogen gas purge nozzle 26 may be started when a leak of harmful gas such as HCl gas is detected by the gas detection nozzle 27. The purge gas or the gas supplied to the seal groove 23 may be an inert gas other than nitrogen gas, such as argon gas or helium gas. The seal groove 23 may be provided in the flange 7a of the reaction tube 7, or may be formed in both the upper flange 13a and the flange 7a.

(Appendix)
The present invention includes the following embodiments.

(Additional remark 1) The semiconductor manufacturing apparatus characterized by making the lower end of the reaction tube made from silicon carbide standing upright on the quartz flange adapter correspond with the lower end of the heater unit heating area surrounding the reaction tube.

(Supplementary Note 2) A silicon carbide reaction tube erected on a quartz flange adapter and a heater unit erected on a heater base via a heat insulating material, the lower end of the reaction tube being connected to the heat insulating material A semiconductor manufacturing apparatus characterized by being aligned with the upper end.

(Additional remark 3) It has the reaction tube made from silicon carbide which accommodates and processes a wafer, and the heater base by which a heater unit is standingly arranged, The lower end of the said reaction tube is provided above the said heater base, It is characterized by the above-mentioned. Semiconductor manufacturing equipment.

(Appendix 4) A flange is formed at the lower end of the reaction tube, a seal groove is formed between the upper flange and the flange of the flange adapter, the flange and the upper flange are polymerized, and a seal gas is supplied to the seal groove. The semiconductor manufacturing apparatus according to Supplementary Note 1 or Supplementary Note 2 supplied.

(Additional remark 5) The semiconductor manufacturing apparatus of Additional remark 4 which provided the gas detection nozzle in the vicinity of the superposition | polymerization position of the said flange of the said reaction tube, and the said upper flange of the said flange adapter.

(Additional remark 6) The semiconductor manufacturing apparatus of additional remark 4 which provided the gas purge nozzle for inert purge gas supply in the vicinity of the superposition | polymerization position of the said flange of the said reaction tube, and the said upper flange of the said flange adapter.

( Supplementary note 7) The semiconductor manufacturing apparatus according to any one of supplementary notes 1 to 3, which performs high-temperature processing at 1200 ° C. or higher.

(Additional remark 8) The semiconductor manufacturing apparatus which has the reaction tube made from silicon carbide which accommodates and processes a wafer, and the heater base by which a heater unit is erected, and provided the lower end of the reaction tube above the heater base A wafer processing method using a wafer, wherein a wafer is charged into the reaction tube, a reaction gas is introduced into the reaction tube, and a required process is performed on the wafer.

DESCRIPTION OF SYMBOLS 1 Heater unit 7 Reaction pipe 13 Flange adapter 13a Upper flange 21 Seal gas introduction port 23 Seal groove 24 Supply communication pipe 25 Exhaust communication pipe 26 Nitrogen gas purge nozzle 27 Gas detection nozzle

Claims (1)

A method of cleaning a reaction tube in a high-temperature treatment furnace such as an oxidation furnace or a diffusion furnace, wherein a flange is formed at the lower end of the reaction tube, a seal groove is formed between the upper flange of the flange adapter and the flange, The flange and the upper flange are polymerized, a seal gas is supplied to the seal groove, and the pressure in the seal groove is made higher than the pressure inside and outside the reaction tube, and HCl gas is used as a cleaning gas in the reaction tube. A method for cleaning a reaction tube , comprising the steps of introducing, and evacuating the seal gas in the seal groove with a cleaning gas through an exhaust communication tube .

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