JP2010186949A - Semiconductor manufacturing apparatus and semiconductor manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method which can achieve high productivity and improve film thickness uniformity. <P>SOLUTION: The apparatus includes a reaction chamber 11 where a wafer w is introduced and subjected to a film forming process, a rotating body 12 on the top of which a holder 13 for holding the wafer w is located and in which heaters 15, 16 for heating the wafer w are located, a rotation drive mechanism 17 connected to the rotating body 12 to rotate the wafer w, a gas supply mechanism for supplying a predetermined flow rate of process gas from above the reaction chamber 11 into the reaction chamber 11, a gas discharging mechanism for discharging the gas from under the reaction chamber to control pressure in the reaction chamber to a predetermined value, a first rectifier plate 20 for rectifying the supplied process gas and supplying the rectified gas to the wafer w held by the holder 13, and a second rectifier plate 21 provided between an inner wall of the reaction chamber 11 and the rotating body 12 and having an opening 21a located to have different opening densities in a horizontal direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method for forming a film while supplying a process gas while heating, for example, on a semiconductor wafer and rotating at high speed.

  In recent years, along with demands for lower prices and higher performance of semiconductor devices, there has been a demand for high productivity in a film forming process as well as improvement in film thickness uniformity and reduction of dust.

  In order to satisfy such a requirement, a method is used in which a single-wafer type epitaxial film forming apparatus is used, heated while rotating at high speed, and a source gas is supplied from above to form a film (see, for example, Patent Document 1). ). For example, while using a large-diameter wafer having a diameter of 300 mm and using a Cl-based source gas such as inexpensive trichlorosilane (hereinafter referred to as TCS) or dichlorosilane, the productivity is further improved.

JP-A-11-67675

  However, when forming a thick epitaxial film exceeding 150 μm, which is used for IGBT (Insulated Gate Bipolar Transistor), for example, the film thickness is reduced especially in the outer peripheral portion of the wafer, and high productivity and uniform film thickness are produced. There is a problem that it is difficult to achieve both improvement in performance.

  An object of this invention is to provide the semiconductor manufacturing apparatus and semiconductor manufacturing method which can aim at the improvement of film thickness uniformity with high productivity.

  The semiconductor manufacturing apparatus of the present invention includes a reaction chamber in which a wafer is introduced and a film forming process is performed, a holder for holding the wafer at the top, a rotating body in which a heater for heating the wafer is installed, and a rotating body. A rotary drive mechanism that is connected to rotate the wafer, a gas supply mechanism that supplies process gas at a predetermined flow rate to the reaction chamber from above the reaction chamber, and gas is discharged from below the reaction chamber to control the reaction chamber to a predetermined pressure. A gas discharge mechanism, a first rectifying plate that rectifies the supplied process gas and supplies it to the wafer held by the holder, and is provided between the inner wall of the reaction chamber and the rotating body, and has an opening density in the horizontal direction. And a second rectifying plate having openings that are arranged differently.

  In the semiconductor manufacturing apparatus of the present invention, a gas discharge port provided below the reaction chamber and connected to the gas discharge mechanism is provided. In the second rectifying plate, the opening density on the gas discharge port is an opening in another region. Desirably less than density.

  In the semiconductor manufacturing apparatus of the present invention, the opening density can be controlled by changing the area of the opening or the number of openings.

  The semiconductor manufacturing method of the present invention also holds the wafer in the reaction chamber, controls the reaction chamber to a predetermined pressure, heats the wafer, rotates it, and rectifies and supplies the process gas onto the wafer from above. Exhaust gas on the wafer containing surplus process gas and reaction by-products generated from the process gas is discharged from the wafer toward the outer periphery by rotating the wafer, and the exhaust gas discharged in the outer peripheral direction is discharged to the outer periphery of the wafer. Control is made so that the discharge speeds in the lower part are equal to each other, the liquid is discharged downward, and discharged from a predetermined position below the reaction chamber.

  In the semiconductor manufacturing method of the present invention, it is desirable to control the discharge speed at the lower peripheral portion of the wafer to be equal by suppressing the discharge speed on a predetermined position below the reaction chamber.

  By using the semiconductor manufacturing apparatus and the semiconductor manufacturing method of the present invention, it is possible to improve the film thickness uniformity as well as high productivity.

It is sectional drawing of the semiconductor manufacturing apparatus by 1 aspect of this invention. It is a top view of the baffle plate in 1 aspect of this invention. It is a figure which shows the flow of the conventional waste gas. It is a figure which shows the flow of the waste gas in 1 aspect of this invention. It is a top view of the baffle plate in 1 aspect of this invention. It is a top view of the baffle plate in 1 aspect of this invention.

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

(Embodiment 1)
FIG. 1 shows a cross-sectional view of the semiconductor manufacturing apparatus of this embodiment. As shown in FIG. 1, a rotating body 12 is installed in a reaction chamber 11 in which a wafer w is formed. A holder (susceptor) 13 for holding the introduced wafer is provided at the upper part of the rotating body 12, and a ring 14 for supporting the holder 13 is provided at the lower part. An in-heater 15 and an out-heater 16 that heat the wafer are installed inside the ring 14. The rotating body 12 is connected to a rotation driving mechanism 17 that rotates the wafer w through an opening at the bottom of the reaction chamber 11.

  A gas supply port 18 for introducing a process gas including a source gas and a dilution gas at a predetermined flow rate is arranged in the reaction chamber 11 at the upper part of the reaction chamber 11. The gas supply port 18 is connected to a gas source (not shown), a gas type and a flow meter (not shown) for controlling the flow rate thereof, and the like, and a gas supply mechanism is configured. In the lower part of the reaction chamber 11, for example, two gas discharge ports 19 for discharging gas from the reaction chamber 11 are arranged. The gas discharge port 19 is connected to a pressure gauge (not shown) for controlling the inside of the reaction chamber 11 to a predetermined pressure, a pump (not shown), etc., and a gas discharge mechanism is configured.

  A rectifying plate 20 is provided above the rotating body 12 to rectify the supplied process gas and supply it to the wafer.

  Between the inner wall of the reaction chamber 11 and the rotator 12, a rectifying plate 21 that rectifies the exhaust gas is provided and fixed to the reaction chamber 11. The rectifying plate 21 has a plurality of circular openings 21a, and the opening diameters of the openings 21a are different in the horizontal direction. That is, as shown in the top view of the rectifying plate in FIG. 2, the opening portion is formed in accordance with the distance from the gas discharge port 19 so that the opening diameter of the opening portion 21a becomes small above the gas discharge port 19 indicated by the broken line. The opening diameter of 21a is varied. In this way, the opening 21 a is formed so that the area of the opening relative to the area between the inner wall of the reaction chamber 11 and the rotator 12 (hereinafter referred to as opening density) decreases according to the distance from the gas discharge port 19. Has been placed.

  Using such a semiconductor manufacturing apparatus, for example, a Si epitaxial film is formed on a Si wafer. First, for example, a φ200 mm wafer w is introduced into the reaction chamber 11 and placed on the holder 13. Next, the liner 21 is lowered, and the flow control plate 20 and the wafer, and the flow control fin 22 and the upper surface of the rotating body 12 are brought closer to each other and controlled so as to be a predetermined distance. And while controlling the temperature of the in-heater 15 and the out-heater 16 so that the temperature of the wafer w may be 1100 degreeC, the wafer w is rotated by 900 rpm by the rotation drive mechanism 17, for example.

  Then, a process gas prepared by diluting with a diluting gas so that the TCS concentration becomes 2.5%, for example, is introduced from the gas supply port 18, for example, by 50 SLM, and the wafer w is rectified through the rectifying plate 20. Then, an Si epitaxial film is grown on the wafer w.

  Excess process gas such as TCS, dilution gas, and reaction by-product such as HCl (exhaust gas) supplied onto the wafer w are exhausted in the outer peripheral direction by the rotation of the wafer w, and the lower gas is exhausted. It is discharged from the outlet 19 and the inside of the reaction chamber 11 is maintained at normal pressure. However, at this time, a part of the gas turbulently flows and stays on the wafer w without being discharged.

In the epitaxial growth using a Cl-based source gas, for example, when TCS is used, when TCS and H ₂ are supplied,
SiHCl ₃ + H ₂ → Si + 3HCl (1)
When the reaction proceeds to the right side, a Si epitaxial film is formed, but HCl is generated together with Si. Since the reaction shown in (1) is an equilibrium reaction composed of a plurality of reactions, when HCl to be discharged stays, the HCl molar ratio on the wafer w increases and the equilibrium shifts to the left. Accordingly, it is considered that the progress of the Si formation reaction is suppressed, and the epitaxial growth rate is reduced at the outer peripheral portion of the wafer w that is easily affected by the retention of HCl.

  In particular, in the region away from the gas discharge port 19 where the exhaust gas is discharged, the discharge direction is slanted as shown in FIG. 3 and the discharge speed is lowered, so that turbulent flow occurs and HCl tends to stay. And while progress of Si is suppressed, Si and other reaction by-products become easy to accumulate in the area | region of the wafer w outer periphery.

  In the present embodiment, since the rectifying plate 21 for rectifying the exhaust gas is provided between the inner wall of the reaction chamber 11 and the rotating body 12, the exhaust direction is vertical as shown in FIG. Without being discharged efficiently. And since discharge speed can be reduced by making the opening diameter of the opening part 21a on the gas discharge port 19 in the baffle plate 21 small, the dispersion | variation in discharge speed can be suppressed. Furthermore, by varying the distance according to the distance from the gas discharge port 19, it is possible to control the discharge speed to be equal, and to suppress the occurrence of turbulence.

  Therefore, even when a Cl-based source gas is used in a single-wafer epitaxial deposition apparatus with high productivity, it is possible to suppress film thickness reduction at the outer peripheral portion of the wafer w and improve film thickness uniformity. It becomes. Further, it is possible to suppress the generation of dust by reducing the amount of deposits on the reaction chamber wall surface.

(Embodiment 2)
FIG. 5 shows a top view of a rectifying plate that rectifies exhaust in the semiconductor manufacturing apparatus of the present embodiment. As shown in FIG. 5, the pattern of the opening 51 a of the rectifying plate 51 is different from that of the first embodiment. That is, in Embodiment 1, the opening diameter of the opening is changed. In this embodiment, the opening diameter of the opening 51a is the same, but the number of openings per unit area is changed. The density is varied.

  Using a semiconductor manufacturing apparatus using such a rectifying plate, for example, a Si epitaxial film can be formed on a Si wafer as in the first embodiment, and the same effect as in the first embodiment can be obtained.

(Embodiment 3)
FIG. 6 shows a top view of a rectifying plate that rectifies the exhaust gas in the semiconductor manufacturing apparatus of the present embodiment. As shown in FIG. 6, the pattern of the opening 61 a of the rectifying plate 61 is different from that of the first embodiment. That is, in Embodiment 1, the opening is circular, but in this embodiment, the opening density is changed by making the opening into a slit shape.

  Using a semiconductor manufacturing apparatus using such a rectifying plate, for example, a Si epitaxial film can be formed on a Si wafer as in the first embodiment, and the same effect as in the first embodiment can be obtained.

  In these embodiments, the shape of the opening of the rectifying plate that rectifies the exhaust gas is a circular shape or a slit shape in the center direction, but is not limited thereto, and is not limited to this, but an elliptical shape or a slit shape in the circumferential direction. It may be. A combination of these may also be used.

  Further, a liner may be provided on the inner wall of the reaction chamber, or a reflector for improving the thermal efficiency may be provided on the outer periphery of the rotating body. In this case, the rectifying plate that rectifies the exhaust gas is installed inside the liner and outside the reflecting plate.

  Furthermore, it is also effective to change the aperture density in accordance with the source gas type used for film formation. For example, when monosilane that is more likely to cause deposits is used as the source gas, the opening density may be made larger than when TCS is used in consideration of the deposit.

  According to these embodiments, it is possible to form a film such as an epitaxial film on the semiconductor wafer w with high productivity and improve the film thickness uniformity. As well as improving the yield of the wafer, it is possible to improve the yield of the semiconductor device formed through the element formation process and the element isolation process and to stabilize the element characteristics.

  In particular, an excellent element can be obtained by being applied to an epitaxial formation process of a power semiconductor device such as a power MOSFET or IGBT that requires a thick film growth of 100 μm or more in an N-type base region, a P-type base region, an insulating isolation region, or the like. It becomes possible to obtain characteristics.

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. Furthermore, for example, the present invention can also be applied to the case where a SiO ₂ film or a Si ₃ N ₄ film is formed on a Si substrate. When forming a SiO ₂ film, N ₂ , O _{2 in} addition to a silane-based gas as a process 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.

w ... wafer 11 ... reaction chamber 12 ... rotor 13 ... holder 14 ... ring 15 ... in heater 16 ... out heater 17 ... rotation drive mechanism 18 ... gas supply port 19 ... gas discharge ports 20, 21, 51, 61 ... rectifying plate 21a , 51a, 61a ... opening

Claims (5)

A reaction chamber in which a wafer is introduced and film formation is performed;
A rotating body in which a holder for holding the wafer is installed at the top and a heater for heating the wafer is installed therein,
A rotation drive mechanism connected to the rotating body and rotating the wafer;
A gas supply mechanism for supplying a predetermined flow rate of process gas to the reaction chamber from above the reaction chamber;
A gas discharge mechanism for discharging gas from below the reaction chamber and controlling the reaction chamber at a predetermined pressure;
A rectifying plate that rectifies the supplied process gas and supplies the process gas onto the wafer held by the holder;
A semiconductor manufacturing apparatus comprising: a rectifying plate provided between an inner wall of the reaction chamber and the rotator, and having an opening portion arranged to have different opening densities in a horizontal direction.   The gas discharge port provided below the reaction chamber and connected to the gas discharge mechanism, wherein the opening density on the gas discharge port is smaller than the opening density in other regions. 2. The semiconductor manufacturing apparatus according to 1.   3. The semiconductor manufacturing apparatus according to claim 1, wherein the opening density is controlled by changing an area of the opening or a number of the openings. Hold the wafer in the reaction chamber,
Controlling the reaction chamber to a predetermined pressure;
While heating and rotating the wafer, the process gas is rectified and supplied onto the wafer from above,
Exhaust gas on the wafer containing surplus process gas and reaction by-products generated from the process gas is discharged from the wafer in the outer peripheral direction by rotation of the wafer,
The exhaust gas discharged in the outer peripheral direction is controlled so that the discharge speed at the lower outer periphery of the wafer is equal, and discharged downward,
A semiconductor manufacturing method, wherein the semiconductor material is discharged outside from a predetermined position below the reaction chamber.   5. The semiconductor manufacturing method according to claim 4, wherein the discharge speed at a lower peripheral portion of the wafer is controlled to be equal by suppressing the discharge speed on a predetermined position below the reaction chamber.

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