JP2008066558A - Semiconductor manufacturing apparatus and semiconductor manufacturing method - Google Patents

Abstract

The present invention provides a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of uniformly forming a film up to the edge of a wafer.
A semiconductor manufacturing apparatus of the present invention includes a reaction chamber 2 into which a wafer to be processed 1 is introduced, a gas supply means 3 for supplying a reaction gas to the reaction chamber from above the reaction chamber, and a reaction gas from the reaction chamber. Gas discharge means 4, a pressure control mechanism 6a, 6b for controlling the pressure in the reaction chamber, a holder 8 for holding the wafer 1 to be processed at the outer periphery, and the wafer 1 to be heated from below. Heaters 9a, 9b, and an upper end of the holder 8 and a lower end of the heaters 9a and 9b. A rectifying fin 10 is provided.
[Selection] Figure 1

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method for forming a film while supplying a reaction gas while heating it from the back surface, for example, on a semiconductor wafer and rotating at high speed.

  In recent years, with the miniaturization of semiconductor devices, high film thickness uniformity in a film forming process is required. A back surface heating method used in a CVD (Chemical Vapor Deposition) apparatus such as an epitaxial growth apparatus does not have a heating source above and can supply a reaction gas in the vertical direction, so that uniform film formation is possible. And in such a back surface heating system, various methods for obtaining better film thickness uniformity have been proposed (see, for example, Patent Document 1).

In recent years, with the miniaturization of elements, the specification of film thickness has become strict. In addition, in order to reduce the cost of the device, the diameter of the wafer is increased, and the demand for increasing the effective area of the wafer is increasing. Therefore, since the film thickness varies by about 1%, it has become necessary to form a film uniformly up to the region near the edge of the wafer that has been deleted from the chip formation region.
JP 2000-306850 A

  As described above, there is a problem that it is difficult to obtain film thickness uniformity up to the edge of the wafer.

  An object of this invention is to provide the semiconductor manufacturing apparatus and semiconductor manufacturing method which can form into a film uniformly to the edge part of a wafer.

  The semiconductor manufacturing apparatus of the present invention includes a reaction chamber into which a wafer to be processed is introduced, a gas supply means for supplying a reaction gas to the reaction chamber from above the reaction chamber, and a gas discharge for discharging the reaction gas from the reaction chamber. Means, a pressure control mechanism for controlling the pressure in the reaction chamber, a holder for holding the wafer to be processed at the outer periphery, a heater for heating the wafer to be processed from below, an upper end above the holder, and a lower end Is provided so as to be positioned below the upper surface of the holder, and includes an annular rectifying fin having a lower end diameter larger than an upper end diameter.

  In the semiconductor manufacturing apparatus of the present invention, it is desirable to further include a drive mechanism for driving the rectifying fins up and down.

  Furthermore, in the semiconductor manufacturing apparatus of the present invention, it is desirable that the length from the upper end to the lower end of the rectifying fin is longer on the inner peripheral side than on the outer peripheral side.

  The semiconductor manufacturing method of the present invention includes a step of holding a wafer to be processed in a reaction chamber, a step of controlling the reaction chamber to a pressure at which a viscous flow is formed, a step of heating and rotating the wafer to be processed, The method includes a step of supplying a reaction gas onto the wafer to be processed, and a step of rectifying the reaction gas at a peripheral portion of the wafer to be processed.

  In the semiconductor manufacturing method of the present invention, it is desirable to set the reaction chamber to 1333 Pa (10 torr) or more. Here, the value of this reduced pressure is supported by the description of J. Vac. Sci. Technol. B 13 (4), Jul / Aug 1995, PP1888-1892.

  By using the semiconductor manufacturing apparatus and the semiconductor manufacturing method of the present invention, it is possible to form a film uniformly up to the edge of the wafer.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a cross-sectional view of the semiconductor manufacturing apparatus of this embodiment. As shown in the figure, a gas supply port 3 for supplying a process gas comprising a film forming gas and a carrier gas from above the reaction chamber 2 and a lower portion of the reaction chamber 2 are formed in the reaction chamber 2 in which the wafer 1 is formed into a film. Further, a gas discharge port 4 for discharging process gas is provided. A pressure gauge 5 is installed in the reaction chamber 2, and pressure control mechanisms 6a and 6b such as a mass flow meter and a valve for controlling the pressure in the reaction chamber 2 in conjunction with the pressure gauge 5 are respectively connected to the gas supply port 3, A gas outlet 4 is provided.

  The reaction chamber 2 is provided with a rotation driving means 7 for rotating the wafer 1 and an annular holder 8 for holding the wafer 1 on the outer periphery of the rotation driving means 7. Below the holder 8, an in-heater 9a and an out-heater 9b for heating the wafer are installed. Further, an annular rectifying fin 10 having a lower end diameter larger than the upper end diameter is installed so that the upper end can be positioned above the holder and the lower end can be positioned below the upper surface of the holder. 11 holds, for example, at three points. A position control mechanism 12 for driving the drive shaft 11 in the vertical direction and controlling the position of the rectifying fin 10 is connected and arranged via the bellows pipe 13 and constitutes a drive mechanism together with the drive shaft 11.

  Above the reaction chamber 2, for example, a temperature measuring mechanism 14 such as a radiation thermometer is installed, and the temperature of the wafer 1 is measured. And based on the temperature measured by the temperature measurement mechanism 14, in order to control the temperature of the heaters 9a and 9b, the temperature control mechanism 15 is connected and arranged.

  Using such a semiconductor manufacturing apparatus, for example, a Si epitaxial film is formed on a wafer 1 made of Si. First, for example, a 12-inch wafer 1 is introduced into the reaction chamber 2 and placed on the holder 6. Here, since the diameter of the wafer 1 is larger than the inner diameter of the rectifying fin 10, for example, the position control mechanism 12 once drives the drive shaft 11 upward via the bellows pipe 13 to move the rectifying fin 10 upward. After that, the wafer 1 is placed on the holder 8, and the drive shaft 11 is driven downward by the position control mechanism 12 through the bellows pipe 13. The end is above the holder and the lower end is below the upper surface of the holder. The rectifying fins 10 are moved downward so as to be positioned at the positions.

Then, from the gas supply port 3, for example, a reactive gas is supplied in a small amount of carrier gas: H ₂ from ₂₀ to 100 SLM, a film forming gas: SiHCl ₃ from 50 sccm to ₂ SLM, a dopant gas: B ₂ H ₆ , and PH ₃ . The gas is discharged from the gas outlet 4. At this time, the pressure in the reaction furnace 2 is controlled to be, for example, 1333 Pa (10 Torr) to normal pressure by the pressure gauge 5 and the pressure control mechanisms 6 a and 6 b. By controlling the pressure in the reaction furnace 2 in this way, a viscous flow is formed in the reaction furnace 2. The viscous flow is formed when the mean free path λ of molecules in the reaction gas that is inversely proportional to the pressure is sufficiently smaller than the size L of the reaction furnace 2.

The supplied reaction gas forms a stable boundary layer 16 while forming a flow in a direction perpendicular to the surface of the wafer 1 as shown in FIG. Then, since the turbulent flow 17 is formed in the vicinity of the end portion of the wafer 1 where the boundary layer is cut, the flow of the reaction gas becomes unstable. However, as shown in FIG. By rectifying in the direction of the fin 10, the flow of the reaction gas in the vicinity of the end portion of the wafer 1 can be stabilized. At this time, as shown in FIG. 4, the rectifying fin 10 preferably has a curved surface, and the length from the upper end to the lower end of the rectifying fin 10 is defined as an outer peripheral side: A and an inner peripheral side: B.
A <B
By doing so, the flow of the reaction gas on the inner peripheral side can be made faster, so that the flow of the reaction gas near the edge of the wafer 1 can be further stabilized. Further, by making the inner diameter of the rectifying fin 10 smaller than the diameter of the wafer 1, it is possible to form a stable boundary layer up to the end of the wafer 1.

  Then, the temperature control mechanism 15 rotates, for example, the temperatures of the in-heater 9a and the out-heater 9b to 1400-1500 ° C. so that the temperature of the wafer 1 measured by the temperature measurement mechanism 14 is uniformly 1100 ° C. The wafer 1 held by the holder 8 is rotated by the driving means 7 to form a Si epitaxial film on the wafer 1.

  In this way, by stabilizing the flow of the reaction gas in the vicinity of the end portion of the wafer 1, it is possible to form a uniform epitaxial film with a variation of 0.5% or less, for example, up to the end portion of the wafer 1. When a semiconductor device is formed through an element formation process and an element isolation process, it is possible to improve yield and stabilize element characteristics. In particular, an epitaxial formation process of a power semiconductor device such as a power MOSFET or IGBT (insulated gate bipolar transistor) that requires a thick film growth of several tens to 100 μm in an N-type base region, a P-type base region, an insulating isolation region, or the like. By applying to the above, it is possible to obtain good element characteristics.

  In the present embodiment, the material of the rectifying fin 10 is not particularly mentioned, but any heat-resistant material having high thermal conductivity and no metal contamination may be used, such as a SiC-based material. For example, it is possible to use a carbon-based material such as a SiC sintered body, an AlN sintered body, a SiN sintered body, or graphite coated with an AlN film, a SiC film, or an iridium film.

  The rectifying fins 10 are held at three points on the drive shaft 11, but may be two points or four or more points as long as they can be stably held. Moreover, you may fix directly to the inner liner provided in the reaction chamber inside. However, in this case, it is premised that it can move up and down.

In addition, this invention is not limited to embodiment mentioned above. For example, in the above-described embodiment, the case where the Si single crystal layer is formed on the Si substrate has been described. The present invention is also applicable to the case where other compound semiconductor layers such as a GaAs layer, GaAlAs, and InGaAs are formed on the compound semiconductor substrate. Further, for example, the present invention can be applied to the case where a SiO ₂ film or a Si ₃ N ₄ film is formed on a Si substrate. In the case of forming a SiO ₂ film, N ₂ , O _{2 in} addition to a silane-based gas as a reaction gas. When Ar gas is supplied to form a Si ₃ N ₄ film, NH ₃ , N ₂ , O ₂ , Ar gas, etc. may be supplied in addition to the silane-based gas. Various other modifications can be made without departing from the scope of the invention.

1 is a cross-sectional view of a semiconductor manufacturing apparatus according to one embodiment of the present invention. The figure which shows the flow of the reactive gas in 1 aspect of this invention. The figure which shows the flow of the reactive gas in 1 aspect of this invention. FIG. 6 is a cross-sectional view of a rectifying fin in one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wafer, 2 ... Reaction chamber, 3 ... Gas supply port, 4 ... Gas discharge port, 5 ... Pressure gauge, 6a, 6b ... Pressure control mechanism, 7 ... Rotation drive means, 8 ... Holder, 9a ... In heater, 9b ... Outheater, 10 ... Rectification fin, 11 ... Drive shaft, 12 ... Position control mechanism, 13 ... Bellows piping, 14 ... Temperature measurement mechanism, 15 ... Temperature control mechanism, 16 ... Boundary layer, 17 ... Turbulent flow

Claims (5)

A reaction chamber into which a wafer to be processed is introduced;
Gas supply means for supplying a reaction gas to the reaction chamber from above the reaction chamber;
Gas discharge means for discharging the reaction gas from the reaction chamber;
A pressure control mechanism for controlling the pressure in the reaction chamber;
A holder for holding the wafer to be processed at the outer periphery,
A heater for heating the wafer to be processed from below;
An upper end is provided above the holder, and a lower end is provided below the upper surface of the holder, and an annular rectifying fin having a lower end diameter larger than the upper end diameter is provided. Semiconductor manufacturing equipment.   The semiconductor manufacturing apparatus according to claim 1, further comprising a drive mechanism for vertically driving the rectifying fins.   The semiconductor manufacturing apparatus according to claim 1, wherein the length from the upper end to the lower end of the rectifying fin is longer on the inner peripheral side than on the outer peripheral side. Holding the wafer to be processed in the reaction chamber;
Controlling the reaction chamber to a pressure at which a viscous flow is formed;
Heating and rotating the wafer to be processed; and
Supplying a reaction gas onto the wafer to be processed;
A semiconductor manufacturing method comprising a step of rectifying the reaction gas in a peripheral portion of the wafer to be processed.   The semiconductor manufacturing method according to claim 4, wherein the reaction chamber is set to 1333 Pa or more.

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