JP2008071939A - Substrate processing equipment - Google Patents

Abstract

【Task】
In a substrate processing apparatus that performs batch processing, in-plane uniformity of the substrate temperature and uniformity between substrates in a steady state and an unsteady state are achieved to improve substrate processing quality.
[Solution]
A substrate processing apparatus for loading a substrate 9 placed in multiple stages in a vertical direction on a boat 8 into the processing chamber 7 and processing the substrate by introducing a processing gas into the processing chamber while heating the substrate with the heater 2. In this case, a plurality of quartz insulating plates 43 made of carbon and sintered by adding carbon to at least one of the upper and lower insulating regions 41 and 42 of the boat were placed.
[Selection] Figure 1

Description

  The present invention relates to a substrate processing apparatus for manufacturing a semiconductor device by performing processes such as thin film generation, impurity diffusion, annealing, and etching on a substrate such as a silicon wafer and a glass substrate.

  As the substrate processing apparatus, there are a single-wafer type substrate processing apparatus that processes substrates one by one, or a batch type substrate processing apparatus that processes a predetermined number of substrates at a time. There is a vertical substrate processing apparatus provided with a mold processing furnace.

  A vertical substrate processing apparatus includes a vertical processing furnace, and the vertical processing furnace includes a reaction tube that defines a processing chamber, a heating device provided around the reaction tube, and a substrate to be processed. (For example, wafers) are stored in the processing chamber while being held in multiple stages in a horizontal posture by a substrate holder. While the wafer and the processing chamber are heated by the heating device, a processing gas is introduced into the processing chamber and exhausted, and a processing (such as a steady state) is performed on the wafer by a low pressure CVD processing in a reduced pressure atmosphere. .

  Wafer processing quality, for example, uniformity of film formation between wafers, or in-plane film quality and film thickness uniformity on the same wafer, is affected by the heating temperature during processing. On the other hand, the processing chamber has heat radiation from the lower furnace port portion of the vertical processing furnace and heat radiation from the upper ceiling portion, and the uniformity is lowered at the upper and lower portions of the processing chamber. Furthermore, the uniformity is further reduced when the wafer is loaded at the start of wafer processing and when the wafer is pulled out after processing.

  For this reason, a heat insulating part on which a quartz heat insulating plate or a SiC heat insulating plate is mounted is provided at the lower part of the substrate holder (boat) (portion close to the furnace port part) to suppress heat release from the furnace port part. Has been. Furthermore, a required number of dummy wafers are mounted on the upper part of the substrate holder to form an upper heat insulating region, and a dummy wafer is mounted on a portion adjacent to the heat insulating part to form a lower heat insulating region. Product wafers for products are mounted on the upper and lower portions of the wafer except for the dummy wafers.

  However, dummy wafers can only be used multiple times. For this reason, a heat insulating plate with no limit on the number of treatments may be used instead of a dummy wafer. Quartz or SiC is selected as the material of the heat insulating plate.

  The thermal properties such as specific heat and thermal conductivity are different between quartz and SiC, and the quartz thermal insulation plate has a large temperature deviation in the substrate surface. The temperature characteristic in the vertical direction of the substrate holder deteriorates at regular times (when the substrate holder is loaded and pulled out). For example, there has been a problem that the temperature rising temperature at both upper and lower ends of the substrate holder is slow.

JP 2000-8167 A

  In view of such circumstances, the present invention is intended to improve the substrate processing quality by achieving in-plane and inter-substrate uniformity of the substrate temperature during steady and non-steady times.

  The present invention provides a substrate processing apparatus for loading substrates placed in multiple stages in a vertical direction on a boat into a processing chamber and introducing a processing gas into the processing chamber while heating the substrate with a heater to process the substrate. In this regard, the present invention relates to a substrate processing apparatus in which a plurality of quartz heat insulating plates sintered by adding carbon is added to at least one of the upper and lower heat insulating regions of the boat.

  According to the present invention, the substrate processing is performed in which the substrates placed in multiple stages in the vertical direction on the boat are loaded into the processing chamber, and the processing gas is introduced into the processing chamber while the substrate is heated by the heater. In the apparatus, since a plurality of quartz heat insulating plates sintered by adding carbon to at least one of the upper and lower heat insulating regions of the boat are mounted, the heating rate of the substrates positioned at the upper and lower portions of the substrate row In addition, the following deviation and the temperature-falling speed deviation can be improved, the in-plane temperature deviation of the substrate can be improved, and the temperature deviation in the wafer row direction in a steady state can be improved.

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

  First, referring to FIG. 1, a vertical processing furnace used in a substrate processing apparatus according to the present invention will be described.

  The processing furnace 1 has a heater 2 as a heating device, the heater 2 has a cylindrical shape, and is installed vertically on a heater base 3 as a support member.

  Inside the heater 2, a process tube 4 is disposed as a reaction tube concentrically with the heater 2. The process tube 4 includes an internal reaction tube 5 and an external reaction tube 6 provided concentrically on the outside thereof.

  The internal reaction tube 5 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC), and has a cylindrical shape with an upper end and a lower end opened. A processing chamber 7 is defined inside the internal reaction tube 5, and a substrate holder (boat 8) can be stored in the processing chamber 7, and wafers 9 are mounted on the boat 8 in multiple stages in a horizontal posture. The

  The outer reaction tube 6 is made of a heat-resistant material such as quartz or silicon carbide, and has an inner diameter larger than the outer diameter of the inner reaction tube 5 and has a cylindrical shape with the upper end closed and the lower end opened.

  Below the external reaction tube 6, a manifold 11 is disposed concentrically with the external reaction tube 6, and the manifold 11 is supported by the heater base 3. The manifold 11 is made of, for example, stainless steel and has a cylindrical shape with an upper end and a lower end opened.

  The inner reaction tube 5 is erected on an inner flange 12 formed on the manifold 11, and the outer reaction tube 6 is erected on an upper end flange of the manifold 11 through a seal member 13 such as an O-ring. Yes.

  A reaction vessel is formed by the internal reaction tube 5, the external reaction tube 6 and the manifold 11, and the lower end opening of the manifold 11 forms a furnace port.

  The furnace port portion is hermetically closed by a seal cap 15 via a seal member 14 such as an O-ring, and the seal cap 15 is provided with a nozzle 16 as a gas introduction portion, and the nozzle 16 is provided in the processing chamber 7. In communication, a gas supply pipe 17 is connected to the nozzle 16.

  The gas supply pipe 17 is connected to a processing gas supply source and an inert gas supply source (not shown) upstream of the nozzle 16. The gas supply pipe 17 is provided with an MFC (mass flow controller) 18 as a gas flow rate controller, and is connected to a processing gas supply source and an inert gas supply source (not shown) via the MFC 18. A gas flow rate control unit 19 is electrically connected to the MFC 18, and the gas flow rate control unit 19 controls the MFC 18 at a desired timing so that the flow rate of the supplied gas becomes a desired amount. It is configured.

  The manifold 11 is provided with an exhaust pipe 21 for exhausting the atmosphere of the processing chamber 7, and the exhaust pipe 21 is a lower end of a cylindrical space 22 formed by the internal reaction tube 5 and the external reaction tube 6. It communicates with the department.

  A vacuum exhaust device 23 such as a vacuum pump is connected to the exhaust pipe 21, and a pressure detector 24 and a pressure adjusting device (for example, a pressure adjusting valve) 25 are provided in the exhaust pipe 21. Is electrically connected to a pressure control unit 26, and the pressure control unit 26 is controlled based on the detection result from the pressure detector 24, and the pressure in the processing chamber 7 is set to a predetermined pressure (vacuum). The vacuum chamber is evacuated so that the pressure in the processing chamber 7 becomes a desired pressure.

  The seal cap 15 is brought into contact with the lower end of the manifold 11 from vertically below. The seal cap 15 is made of, for example, a metal such as stainless steel and is formed in a disk shape. A rotation mechanism 27 that rotates the boat 8 is installed on the side of the seal cap 15 opposite to the processing chamber 7.

  A rotating shaft 28 of the rotating mechanism 27 passes through the seal cap 15 and is connected to a boat pedestal 29 so that the boat 8 is placed on the boat pedestal 29. The rotating mechanism 27 is configured to rotate the boat 8 and the wafer 9 together via the rotating shaft 28 and the boat receiving base 29.

  A boat elevator 31 as an elevating mechanism is provided below the process tube 4, and the seal cap 15 is configured to be vertically moved by the boat elevator 31, and the boat elevator 31 moves the boat 8 to the The processing chamber 7 can be charged and withdrawn. A drive control unit 32 is electrically connected to the rotation mechanism 27 and the boat elevator 31, and is configured to control at a desired timing so as to perform a desired operation.

  A temperature sensor 35 as a temperature detector is installed in the process tube 4. The heater 2 and the temperature sensor 35 are electrically connected to a temperature control unit 36. The heater 2 is also provided with a heating source temperature sensor (not shown), and the heating source temperature sensor is electrically connected to the temperature controller 36.

  The energization state of the heater 2 is adjusted based on temperature information detected by the temperature sensor 35 and the heating source temperature sensor (not shown) so that the temperature of the processing chamber 7 becomes a desired temperature and temperature distribution. It is configured to control at a desired timing.

  The gas flow rate control unit 19, the pressure control unit 26, the drive control unit 32, and the temperature control unit 36 also constitute an operation unit and an input / output unit, and are electrically connected to a main control unit 37 that controls the entire substrate processing apparatus. Connected. The gas flow rate control unit 19, the pressure control unit 26, the drive control unit 32, the temperature control unit 36, and the main control unit 37 are configured as a controller 38.

  The boat 8 is made of a heat-resistant material such as quartz or silicon carbide, for example, a heat insulating portion 33 is formed in the lower portion of the boat 8, and a lower heat insulating region 41 is formed in a portion adjacent to the heat insulating portion 33, An upper heat insulating region 42 is formed in the upper portion of the boat 8.

  In the heat insulating portion 33, a disk-shaped quartz heat insulating plate 34 (described later) made of a heat-resistant material is mounted in multiple stages in a horizontal posture, and heat from the heater 2 is transmitted to the manifold 11 side. It is configured to be difficult.

  A required number of carbon-added heat insulating plates 43 are mounted on the lower heat insulating region 41 and the upper heat insulating region 42.

  The carbon-added heat insulating plate 43 is obtained by adding (mixing) less than several percent by weight of carbon to a quartz material, and is preferably sintered so that carbon does not dissolve in the quartz material.

  Such a carbon-added heat insulating plate 43 has substantially the same mechanical properties as a quartz material, and has a temperature characteristic in which the quartz material and the SiC material are combined.

  That is, when a required number of wafers are mounted in the lower heat insulating region 41 and the upper heat insulating region 42, the thermal conductivity in the wafer mounting direction (row direction) in a steady state is small, and the temperature deviation between the wafers is reduced. It also has the characteristics as a material, and also has the characteristics as a SiC material that has a large thermal conductivity and reduces the in-plane temperature deviation of the wafer located at the upper and lower parts of the boat in a steady state. Further, the heat capacity of the carbon-added heat insulating plate 43 is large, and the carbon-added heat insulating plate 43 reduces the temperature deviation in the row direction of the wafer when the temperature is lowered.

  Next, a method of forming a thin film on the wafer 9 by the CVD method as one step of the semiconductor device manufacturing process using the processing furnace 1 having the above configuration will be described. In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 38.

  The wafers 9 are loaded in a wafer cassette (substrate transfer container) in a state where a required number (for example, 25) is stored, stored in a required portion such as a cassette shelf by a cassette transfer machine, and stored in a cassette by a substrate transfer machine. Wafers 9 are transferred to the boat 8.

  When a predetermined number of wafers 9 are mounted on the boat 8 (wafer charging), the boat 8 holding the predetermined number of wafers 9 is lifted by the boat elevator 31 and carried into the processing chamber 7 (boat). Loading). In this state, the seal cap 15 is in a state of hermetically closing the furnace port portion via the seal member 14.

  The processing chamber 7 is evacuated by the evacuation device 23 so as to have a desired pressure (degree of vacuum). At this time, the pressure in the processing chamber 7 is measured by the pressure detector 24, and the pressure adjusting device 25 is feedback-controlled based on the measurement result.

  Further, the processing chamber 7 is heated by the heater 2 so as to reach a desired temperature. At this time, the energization state of the heater 2 is feedback-controlled based on temperature information detected by the temperature sensor 35 so that the processing chamber 7 has a desired temperature and temperature distribution.

  Subsequently, the boat 9 is rotated by the rotating mechanism 27, whereby the wafer 9 is rotated.

  Next, a processing gas is supplied from a processing gas supply source (not shown), and a gas controlled to have a desired flow rate by the MFC 18 flows through the gas supply pipe 17 and is supplied from the nozzle 16 to the processing gas. It is introduced into the chamber 7. The introduced gas rises in the processing chamber 7, flows down from the upper end opening of the internal reaction tube 5 to the cylindrical space 22, and is exhausted from the exhaust pipe 21. The gas comes into contact with the surface of the wafer 9 as it passes through the processing chamber 7, and is deposited on the surface of the wafer 9 by a thermal CVD reaction to produce a thin film.

  When a preset processing time elapses, an inert gas is supplied from an inert gas supply source (not shown), the processing chamber 7 is replaced with the inert gas, and the pressure in the processing chamber 7 is constantly maintained. Return to pressure.

  Thereafter, the seal cap 15 is lowered by the boat elevator 31 to open the furnace port, and the processed wafer 9 is pulled out from the processing chamber 7 while being held in the boat 8. The processed wafer 9 is discharged from the boat 8 by the substrate transfer machine (not shown) from the lowered boat 8 and transferred to a wafer cassette (not shown).

  The wafer cassette containing the processed wafer 9 is transferred to the outside of the substrate processing apparatus via a cassette transfer machine.

  In the above-described substrate processing step, by mounting the carbon-added heat insulating plate 43 on the lower heat insulating region 41 and the upper heat insulating region 42, the temperature deviation in the wafer row direction in a steady state may be made of other materials such as quartz. Compared to the case of using a heat insulating plate. That is, the cooling of the temperature at the upper and lower end portions of the wafer row is improved, and the temperature is equal to that of the other portions of the wafer.

  Further, by mounting the carbon-added heat insulating plate 43 on the lower heat insulating region 41 and the upper heat insulating region 42, the temperature deviation in the wafer row direction and the temperature deviation in the wafer surface at the time of temperature rise may be made of other materials such as quartz. It becomes smaller than the case where an insulation board is used. That is, the temperature increase rate in the upper and lower end regions of the wafer is increased, and a temperature increase rate equivalent to that of the other portions of the wafer is obtained.

  Further, by mounting the carbon-added heat insulating plate 43 on the lower heat insulating region 41 and the upper heat insulating region 42, the temperature deviation in the wafer row direction and the temperature deviation in the wafer surface during the temperature drop are insulated from other materials such as quartz. Smaller than when using a plate. That is, the temperature lowering rate in the upper and lower end region of the wafer is slow, and the temperature decreasing rate is the same as that of the wafers in other portions.

  In addition, when using the said carbon addition heat insulation board 43, you may mount in combination with the heat insulation board of another material. For example, the carbon-added heat insulating plates 43 and other heat insulating plates may be mounted alternately. Further, a dummy wafer having the same thermal characteristics is used for a portion adjacent to or close to the product wafer in the lower heat insulating region 41 and the upper heat insulating region 42, and the carbon-added heat insulating plate 43 is used for the other portions. Also good.

  In addition, the heat insulating plates mounted on the lower heat insulating region 41 and the upper heat insulating region 42 may be alternately mounted with the carbon-added heat insulating plate 43 and the SiC heat insulating plate.

  Further, all of the heat insulating plates mounted on the heat insulating portion 33 may be made of quartz or the carbon-added heat insulating plate 43. Alternatively, the carbon-added heat insulating plate 34 and a heat insulating plate made of quartz or a heat insulating plate made of SiC may be mixed.

  Furthermore, in the above embodiment, the heat insulating portion 33 is formed in the lower portion of one boat 8, but the lower portion of the boat 8 is separated, and a carbon-added heat insulating plate 34 is mounted on the separated portion to form the heat insulating portion 33. May be.

  As an example, the processing conditions for processing a wafer in the processing furnace of the present embodiment include, for example, a processing temperature of 600 to 800 ° C. and a processing pressure of 10 to 100 Pa in the formation of a Si3 N4 film. Gas species, gas supply flow rate DCS 20-50 sccm, and ammonia 100-200 sccm are exemplified, and the wafer is processed by keeping each processing condition constant at a certain value within each range.

(Appendix)
The present invention includes the following embodiments.

  (Supplementary note 1) A substrate processing apparatus for loading substrates placed in multiple stages in a vertical direction on a boat into a processing chamber and introducing the processing gas into the processing chamber while heating the substrate with a heater to process the substrate A substrate processing apparatus, wherein a plurality of quartz heat insulating plates sintered by adding carbon to the upper and lower ends of the substrate placed on the boat are placed.

  (Supplementary note 2) A substrate processing apparatus for loading substrates placed in multiple stages in a vertical direction on a boat into a processing chamber and introducing a processing gas into the processing chamber while heating the substrate with a heater to process the substrate In this case, one or more silicon carbide heat insulating plates are placed on the upper and lower ends of the substrate placed on the boat, and the quartz heat insulating plates are sintered by adding carbon to the upper and lower ends of the heat insulating plates. A substrate processing apparatus on which one or more sheets are placed.

It is a schematic sectional drawing of the processing furnace which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing furnace 2 Heater 4 Process tube 7 Processing chamber 8 Boat 9 Wafer 15 Seal cap 17 Gas supply pipe 21 Exhaust pipe 25 Pressure regulator 31 Boat elevator 33 Heat insulation part 34 Heat insulation board 35 Temperature sensor 41 Lower heat insulation area 42 Upper heat insulation area 43 Carbon-added insulation board

Claims (1)

  In a substrate processing apparatus for loading a substrate placed in multiple stages in a vertical direction on a boat into a processing chamber, and processing the substrate by introducing a processing gas into the processing chamber while heating the substrate with a heater, A substrate processing apparatus, comprising: a plurality of quartz heat insulating plates sintered with carbon added to at least one of upper and lower heat insulating regions of a boat.

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