JP2006093200A - Semiconductor manufacturing equipment - Google Patents

Abstract

【Task】
The deformation of the reaction tube used in the high temperature process is reduced, and the running cost of the semiconductor manufacturing apparatus is reduced.
[Solution]
A vertical reaction tube 2 that accommodates and processes the substrate and a heating device that accommodates and heats the reaction tube, and the thickness of the reaction tube is lower side wall> ceiling portion> upper side wall. Yes.
[Selection] Figure 2

Description

  The present invention relates to a semiconductor manufacturing apparatus that manufactures a semiconductor device by performing necessary processes such as generation of a thin film such as an oxide film, diffusion of impurities, and etching on a substrate such as a silicon wafer.

  Semiconductor manufacturing apparatuses include a single wafer type semiconductor manufacturing apparatus that processes substrates one by one, a batch type semiconductor manufacturing apparatus that processes a required number of substrates at once, and a vertical type semiconductor manufacturing apparatus as an example. There is a semiconductor manufacturing apparatus having a mold furnace.

  With reference to FIG. 3, a vertical furnace of a conventional semiconductor manufacturing apparatus, for example, an oxidation / diffusion processing furnace will be described.

  The soaking tube 1 is made of a heat-resistant material such as SIC, for example, and has a cylindrical shape with the upper end closed and the lower end opened. For example, a reaction vessel (hereinafter referred to as reaction tube 2) made of a heat-resistant material such as quartz (SiO 2) has a cylindrical shape having an opening at the lower end, and is arranged concentrically in the soaking tube 1. A heating device (hereinafter referred to as a heater 10) is concentrically arranged so as to accommodate the soaking tube 1. The temperature in the reaction tube 2 is detected by a temperature detecting means (hereinafter referred to as a thermocouple 11), and heating by the heater 10 is controlled based on the detection result so that the inside of the reaction tube 2 is set to a predetermined processing temperature.

  A gas supply pipe 3 and a gas exhaust pipe 4 made of, for example, quartz are connected to the lower part of the reaction tube 2, and a narrow pipe 6 is connected to the introduction port 5 communicating with the gas supply pipe 3. Rises from the bottom of the reaction tube 2 along the outer surface and communicates with the gas reservoir 7 at the ceiling. The gas reservoir 7 and the inside of the reaction tube 2 communicate with each other through a dispersion hole 8 formed in the ceiling. The gas exhaust pipe 4 is connected to an exhaust port 9 provided at the lower end of the reaction tube 2.

  The introduction port 5 of the reaction tube 2 is configured so that a reaction gas is supplied into the reaction tube 2 through the gas supply tube 3, and the reaction gas is supplied from the gas supply tube 3 to the conduit 6 and the gas reservoir. The gas is introduced into the reaction tube 2 from the ceiling of the reaction tube 2 through the section 7, and the gas after the reaction is exhausted from the gas exhaust tube 4.

  A disc-shaped base (for example, base 12) made of, for example, quartz is detachably attached to the lower end opening of the reaction tube 2 so as to be hermetically sealed. The base 12 is a disc-shaped lid (hereinafter, seal cap 13). Installed on top. The seal cap 13 is connected to a rotating means 14 composed of a rotary motor or the like. By the rotating means 14, a holder (hereinafter referred to as a quartz cap 15), a substrate holder (hereinafter referred to as a boat 16), The held substrate (hereinafter referred to as wafer 17) is rotated.

  The seal cap 13 is connected to elevating means (hereinafter referred to as a boat elevator 18). The boat elevator 18 can elevate and lower the boat 16, and the boat 16 can be loaded into and withdrawn from the reaction tube 2. .

  Hereinafter, the substrate processing will be described.

  First, the boat 16 is lowered by the boat elevator 18 and a predetermined number of wafers 17 are loaded into the boat 16. Next, the reaction tube 2 is heated by the heater 10, and the temperature in the reaction tube 2 is set to a predetermined processing temperature. The boat elevator 18 raises the boat 16 and inserts it into the reaction tube 2. The heater 10 is controlled based on the temperature detected by the thermocouple 11, and the internal temperature of the reaction tube 2 is set to a predetermined value. Maintained at temperature.

  After maintaining the inside of the reaction tube 2 at a predetermined pressure, the rotating means 14 rotates the boat 16 and the wafer 17 held on the boat 16 and simultaneously supplies the reaction gas from the gas supply tube 3. Alternatively, water vapor is supplied from a moisture generator (not shown). The supplied reaction gas descends the reaction tube 2 through the conduit 6 and the gas reservoir 7 and is evenly supplied to the wafer 17, and oxidation / diffusion processing is performed on the wafer 17.

  When the oxidation / diffusion process is completed, the reaction gas in the reaction tube 2 is replaced with an inert gas and the pressure is changed to normal pressure, and then the boat elevator 18 moves to the next wafer 17 oxidation / diffusion process. The boat 16 is lowered, and processed wafers 17 are discharged from the reaction tube 2 from the boat 16. An unprocessed wafer 17 is loaded into the emptied boat 16 and charged again into the reaction tube 2 in the same manner as described above, and oxidation / diffusion processing is performed.

  The substrate processing is performed at a processing temperature of 1000 ° C. when an oxide film is processed, for example, or at a processing temperature of 1200 ° C. when an annealing process is performed. ° C. is a temperature close to the heat-resistant temperature of quartz, and the strength of quartz is also lower than that at 1000 ° C. In the reaction tube 2 used at 1200 ° C., the lower part of the reaction tube 2 is deformed by its own weight as shown in FIG. 4 by repeated use. For this reason, the reaction tube 2 used at 1200 ° C. must be frequently replaced as compared to the reaction tube 2 used at 1000 ° C.

  In view of such circumstances, the present invention reduces deformation of a reaction tube used in a high-temperature process and reduces the running cost of a semiconductor manufacturing apparatus.

  The present invention comprises a vertical reaction tube that accommodates and processes a substrate, and a heating device that accommodates and heats the reaction tube, and the thickness of the reaction tube is: lower side wall> ceiling portion> upper side wall This relates to the semiconductor manufacturing apparatus.

  According to the present invention, a vertical reaction tube that accommodates and processes a substrate and a heating device that accommodates and heats the reaction tube are provided, and the thickness of the reaction tube is lower side wall> ceiling portion> Since it is the upper part of the side wall, it is possible to increase the strength of the lower part without increasing the weight of the reaction tube, and to suppress the deformation at the lower part where the deformation of the reaction tube is concentrated. Demonstrate.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  First, referring to FIG. 1, an outline of a semiconductor manufacturing apparatus in which the present invention is implemented will be described.

  In FIG. 1, the same components as those shown in FIG.

  The heater 10 is erected on the heater base 21, the soaking tube 1 is concentrically accommodated in the heater 10, and the reaction tube 2 is concentrically disposed in the soaking tube 1.

  An introduction port 5 is attached to the lower end of the reaction tube 2, and the introduction port 5 is connected to a processing gas supply source (not shown) or an inert gas (purge gas) supply source such as nitrogen gas via a gas supply tube 3. The gas supply pipe 3 is connected to a flow rate control means, for example, a mass flow controller 22. An exhaust port 9 communicates with the lower end of the reaction tube 2, and the exhaust port 9 is connected to an exhaust device (not shown) via a gas exhaust tube 4. The gas exhaust tube 4 has a pressure sensor 23 and a pressure adjustment. A vessel 24 is provided.

  A conduit 6 communicates with the introduction port 5, the conduit 6 rises along the outer surface of the reaction tube 2, communicates with a gas reservoir 7 provided on the upper end surface of the reaction tube 2, and the gas reservoir The part 7 communicates with the inside of the reaction tube 2 through the dispersion hole 8.

  A boat 16 can be inserted into and withdrawn from the reaction tube 2. The boat 16 is placed on a seal cap 13 via a quartz cap 15 and a base 12, and the seal cap 13 is attached to the reaction tube 2. It is possible to hermetically close the open surface of the lower end. The seal cap 13 is supported by a boat elevator 18, and the boat elevator 18 can raise and lower the quartz cap 15 and the boat 16 through the seal cap 13, and the boat 16 is inserted into the reaction tube 2 by raising and lowering. It is possible to remove.

  The quartz cap 15 can be rotated with respect to the base 12, and the quartz cap 15 can be rotated by a rotating means 14.

  In FIG. 1, reference numeral 25 denotes a main control unit, and the main control unit 25 includes a temperature control unit 26, a gas flow rate control unit 27, a pressure control unit 29, and a drive control unit 28.

  The detection result from the thermocouple 11 that detects the temperature of a required location in the furnace is input to the temperature control unit 26, and the temperature control unit 26 determines that the inside of the reaction tube 2 is at a predetermined temperature, for example, a process based on the temperature detection result. The heater 10 is controlled to reach the temperature. The gas flow rate control unit 27 controls the reaction gas introduced from the introduction port 5 to a predetermined flow rate, and the pressure control unit 29 is based on the pressure input from the pressure sensor 23. To control the pressure in the reaction tube 2 to a predetermined pressure, for example, a process pressure.

  The drive control unit 28 controls the rotating means 14 to rotate the boat 16 being processed at a predetermined rotational speed, and controls the boat elevator 18 to raise and lower the boat 16.

  Hereinafter, an example of substrate processing, for example, oxidation / diffusion processing will be described.

  The boat elevator 18 is driven to lower the boat 16.

  A predetermined number of wafers 17 are transferred onto the boat 16 by a wafer transfer machine (not shown). The reaction tube 2 is heated by the heater 10 through the soaking tube 1, and the temperature in the reaction tube 2 is determined based on the temperature in the reaction tube 2 detected by the thermocouple 11. It is controlled at 1200 ° C. In addition, the inside of the reaction tube 2 is supplied with an inert gas from the introduction port 5 and the conduit 6 in advance, and is filled with the inert gas.

  The boat 16 loaded with unprocessed wafers 17 is loaded into the reaction tube 2 by the boat elevator 18. In the loaded state of the boat 16, the base 12 airtightly closes the lower end opening of the reaction tube 2. Based on the pressure detected by the pressure sensor 23, the pressure in the reaction tube 2 is maintained at a processing pressure, for example, 50 Pa.

  The rotating means 14 is driven, and the wafer 17 is rotated through the boat 16. At the same time, the reaction gas or water vapor is supplied from the gas supply pipe 3. The supplied reaction gas descends the reaction tube 2 from the gas reservoir 7 through the dispersion hole 8 and is evenly supplied to the wafer 17 to perform required processing of oxidation and diffusion. . The exhaust gas is exhausted through the gas exhaust pipe 4 in the reaction tube 2 during the oxidation / diffusion treatment, and the pressure is controlled by the pressure regulator 24 so as to reach a predetermined pressure.

  When the substrate processing is completed, the inside of the reaction tube 2 is purged with an inert gas, the boat 16 is lowered by the boat elevator 18, and the processed wafer 17 is discharged.

  The unprocessed wafer 17 is transferred to the empty boat 16 and the above processing is repeated.

  Note that, up to one example, the processing conditions of the substrate processed in the present invention are: annealing, the wafer temperature is 1200 ° C., the gas species supply amount is Ar gas, 10 m / min, and the processing pressure is 50 Pa.

  As described above, the reaction tube 2 is heated to a high temperature during processing. The material of the reaction tube 2 is quartz, and the temperature at which quartz is easily deformed is 1150 ° C. During the treatment, when the reaction tube 2 is used at a temperature of 1200 ° C., the temperature exceeds the temperature at which it easily deforms and is close to the heat-resistant temperature, and the strength of the reaction tube 2 is also reduced.

  A vertical load due to its own weight is acting on the side wall of the reaction tube 2, and deformation due to the vertical load occurs at a high temperature during processing. The deformation accumulates as the process is repeated, and finally becomes a deformation that can no longer be used.

  In the present invention, in order to reduce the deformation of the side wall of the reaction tube 2 during the substrate processing, the thickness of the side wall is increased, the strength of the side wall is increased, and the deformation amount of the side wall is reduced. That is, the thickness of the reaction tube 2 is set such that a relationship of lower side wall> ceiling part> upper side wall is established.

  The ceiling part is the top part of the reaction tube 2, and unlike the lower part of the side wall, it is not necessary to load the weight of the upper part and the upper part of the side wall. However, since the plane or curved surface of the ceiling portion is arranged in the horizontal direction with respect to gravity, it is easy to hang down, so that the wall thickness must be thicker than the lower portion of the side wall.

  In order to realize the optimum state of the present invention, the present inventors conducted confirmation experiments.

  To summarize the results of the experiment, when the wall thickness is increased over the entire reaction tube 2, the weight of the upper portion of the reaction tube 2 increases, and deformation also occurs at the lower portion. Further, when the thickness of the 2/3 portion is increased from the bottom of the side wall, the amount of deformation decreases, but deformation occurs in the lower part. Further, when the thickness of only the lower end portion of the reaction tube 2 (1/5 of the total length) was increased, the strength was not improved and the effect of reducing deformation was not observed.

  Next, when the thickness in the range of about 2/5 of the total height from the bottom of the reaction tube 2 was increased, the result was that the balance between strength and weight was good and the amount of deformation was the smallest. It has been found that increasing the thickness in the range of 1/3 to 1/4 from the bottom of the reaction tube 2 has the effect of reducing deformation at the lower portion of the reaction tube 2. For example, in this embodiment, the increase ratio of the thickness is 2/1. The increase ratio of the wall thickness is appropriately selected depending on the shape of the reaction tube 2 and is selected in the range of 3/1 to 1.5 / 1.

  Next, temperature management is given as a wafer processing condition. When the thickness of the side wall of the reaction tube 2 is changed, the heating of the wafer 17 accommodated in the reaction tube 2 (soaking control) is affected. Arise. For this reason, it is preferable that the range in which the thickness is changed does not overlap with the range in which the wafer 17 to be processed is accommodated (the soaking area in the reaction tube 2). Therefore, it is preferable that the range in which the thickness of the side wall is actually increased does not overlap the soaking area.

  FIG. 2 shows a reaction tube 2 in which the present invention is implemented in consideration of the above experiment.

  As shown in the figure, the thickness is thicker in the range of the lower portion L of the side wall of the reaction tube 2. Further, the boundary portion where the thickness changes is tapered or R-finished so that thermal stress is not concentrated.

  In addition, although this invention showed the case where it implemented to a reaction tube, it cannot be overemphasized that it can implement to the pipe | tube used at high temperature, such as a soaking | uniform-heating pipe | tube.

It is a section schematic diagram showing an embodiment of the invention. It is sectional drawing of the reaction tube used for this Embodiment. It is the cross-sectional schematic which shows a prior art example. It is explanatory drawing which shows the aspect of a deformation | transformation of the reaction tube in a prior art example.

Explanation of symbols

1 Heat equalizing tube 2 Reaction tube 10 Heater 16 Boat 17 Wafer 18 Boat elevator 25 Main controller

Claims (1)

  A vertical reaction tube that accommodates and processes the substrate, and a heating device that accommodates and heats the reaction tube, and the thickness of the reaction tube is lower side wall> ceiling portion> upper side wall. A semiconductor manufacturing apparatus.

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