JP5757748B2 - Semiconductor manufacturing apparatus and semiconductor manufacturing method - Google Patents

Description

  The present invention relates to a semiconductor manufacturing apparatus and a semiconductor manufacturing method used for forming a film on a semiconductor wafer using, for example, Si source gas.

For example, in a Si epitaxial growth apparatus, H ₂ gas as a carrier gas, SiH ₂ Cl ₂ gas, SiHCl ₃ gas or the like as a source gas are mixed and supplied as a process gas into a reaction chamber. Then, for example, the wafer temperature is set to about 1100 ° C., and Si is epitaxially grown on the wafer by hydrogen reduction reaction.

  At this time, in order to remove reaction by-products such as polysilicon deposited on a member such as a susceptor in the reaction chamber, cleaning (etching process) using a chlorine-based gas such as HCl gas is periodically performed. At this time, a Si—H—Cl polymer is generated as a reaction by-product in the reaction chamber, cooled in the vicinity of the exhaust port, and deposited as oily silane (reactive polysiloxane).

The oily silane deposited in this way is usually removed during regular maintenance of the reaction chamber to prevent the exhaust system from being blocked. However, there is a problem that the surface reacts with moisture in the atmosphere when being released into the atmosphere to generate H ₂ gas and HCl gas (for example, see Patent Document 1).

JP 2008-1112919 A (Claim 1 etc.)

When the reaction chamber is opened to the atmosphere, the oily silane reacts with moisture in the atmosphere to generate H ₂ gas and HCl gas, but the surface becomes SiO _{2 and} solidifies, and further reaction is suppressed. However, in the vertical plane, the deposited oily silane becomes almost SiO _{2 and} is solidified, so there is no problem. Therefore, there is a risk of H ₂ gas ignition and explosion. In particular, this is a problem in a single-wafer epitaxial growth apparatus in which the frequency of air release is low and oily silane tends to accumulate.

  Therefore, it has been studied to remove oily silane without opening it to the atmosphere. If the surface of the oily silane is oxidized, the oxidation of the lower layer is suppressed. Therefore, it is necessary to repeatedly remove the surface with the oxidized oily silane F-based gas and oxidize the exposed lower layer of oily silane, which affects the throughput.

  In this case, in the epitaxial growth of Si by the hydrogen reduction reaction, if the F-based gas remains, it reacts explosively, so that sufficient gas replacement is required, which also greatly affects the throughput.

  Further, as described above, polysilicon or the like is usually removed using a gas containing Cl (Cl-based gas). In this case, the deposited polysilicon or the like is oxidized by introducing an oxidizing gas. It cannot be removed with Cl-based gas. In order to remove this, it is necessary to introduce F-type gas and to disassemble and maintain the apparatus, which further reduces the throughput.

  Therefore, an object of the present invention is to provide a semiconductor manufacturing apparatus and a semiconductor manufacturing method capable of safely removing oily silane without reducing throughput.

A semiconductor manufacturing apparatus of one embodiment of the present invention includes a reaction chamber into which a wafer is introduced, a process gas supply mechanism that supplies a process gas to the reaction chamber, a wafer support member on which the wafer is placed, and the wafer at a predetermined temperature. A heater for heating, a rotation drive control mechanism for rotating the wafer, a gas discharge mechanism including an exhaust port for discharging gas from the reaction chamber , and above the exhaust port corresponding to the exhaust port, and the wafer comprises an oxidizing gas supply ports provided below the horizontal position of the supporting member, each of the wafer after the film forming process is unloaded from the reaction chamber, on the Oirishira emissions deposited on the silicon oxide in the exhaust opening top, And an oxidizing gas supply mechanism for supplying an oxidizing gas from the oxidizing gas supply port .

  In the semiconductor manufacturing apparatus of one embodiment of the present invention, it is preferable to provide a liner made of quartz on the inner wall of the reaction chamber above the exhaust port.

  In the semiconductor manufacturing apparatus of one embodiment of the present invention, it is preferable that a gap between the inner wall and the liner is sealed.

In addition, in the semiconductor manufacturing method of one embodiment of the present invention, a wafer is introduced into a reaction chamber and held at a predetermined position, the wafer is heated at a predetermined temperature, the wafer is rotated, and a process gas containing Si source gas on the wafer. The film is formed on the wafer, and the film-formed wafer is unloaded from the reaction chamber. Each time the wafer is unloaded, it is deposited on the oily silane deposited on the silicon oxide at the upper part of the exhaust port. An oxidizing gas is supplied from below from a predetermined position , and the oxidizing gas is removed from the reaction chamber before the next film forming process is performed on another wafer .

Further, in one aspect a method of semiconductor manufacturing of the present invention, after repeating a predetermined period a series of steps up to the supply of oxidative gas onto oily silane from the introduction of the wafer into the reaction chamber, deposition containing silicon oxide It is preferable to remove substances from the reaction chamber.

  According to one embodiment of the present invention, oily silane can be removed safely without reducing throughput in a semiconductor manufacturing process.

It is sectional drawing which shows the structure of the epitaxial film-forming apparatus of 1 aspect of this invention. It is sectional drawing of the gas exhaust port in 1 aspect of this invention. It is a schematic diagram which shows the deposition state of the oily silane of the gas exhaust port in 1 aspect of this invention. It is sectional drawing of the gas exhaust port in 1 aspect of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a cross-sectional view of an epitaxial film forming apparatus which is a semiconductor manufacturing apparatus of this embodiment. As shown in the figure, for example, a process gas containing a source gas such as trichlorosilane or dichlorosilane is supplied from above the reaction chamber 11 to the reaction chamber 11 in which a wafer w having a diameter of 200 mm is processed at a predetermined flow rate. The gas supply port 12a connected with the gas supply mechanism 12 for supplying on w is installed. A liner 11 a made of, for example, quartz is provided on the inner wall of the reaction chamber 11.

  On the bottom surface of the reaction chamber 11, for example, gas discharge ports 13 a connected to a gas discharge mechanism 13 for discharging gas and controlling the pressure in the reaction chamber 11 to be constant (normal pressure) are arranged at two locations, for example. ing. On the inner wall of the gas discharge port 13a, a liner 11b made of quartz, for example, separated from the liner 11a is provided.

  FIG. 2 shows a cross-sectional view of the gas discharge port 13a. As shown in the figure, a cup-shaped liner 11b is provided on the inner wall of the gas discharge port 13a, and an opening for discharging gas is provided on the bottom surface thereof.

  An oxidizing gas for supplying a gas containing a gas that oxidizes oily silane (to be described later) such as oxygen gas, ozone gas, and water vapor (hereinafter referred to as an oxidizing gas) to the upper portion of the gas outlet 13a. An oxidizing gas supply port 14 a connected to the supply mechanism 14 is provided.

  A rectifying plate 15 for supplying the process gas supplied from the gas supply port 12a onto the wafer w in a rectified state is installed in the upper part of the reaction chamber 11. Below that, a susceptor 16 as a holding member for holding the wafer w is installed on a ring 17 as a rotating member. The holding member may be an annular holder. The ring 17 is connected to a rotation drive control mechanism 18 including a rotation shaft 18a that rotates the wafer w at a predetermined rotation speed, a motor (not shown), and the like.

  In the ring 16, for example, a disk-shaped heater 19 made of SiC is installed to heat the wafer w. The heater 19 may be formed with a pattern in order to heat it uniformly. As the heater 19, an annular heater for heating the peripheral portion of the wafer w may be used, and a reflector for efficiently heating may be provided.

  Using the epitaxial film forming apparatus configured as described above, for example, a Si epitaxial film is formed on a Si wafer w having a diameter of 200 mm.

  First, the wafer w is loaded into the reaction chamber 11, and the susceptor 16 on which the wafer w is placed is placed on the ring 17. Then, the temperature of the heater 19 is controlled to 1500 to 1600 ° C. so that the in-plane temperature of the wafer w is uniformly 1100 ° C., for example.

Then, the rotational drive control mechanism 18 rotates the wafer w at, for example, 900 rpm, and the process gas is rectified on the wafer w from the gas supply mechanism 12 through the gas supply port 12a and through the rectifying plate 15. Supply. The process gas is diluted with a diluent gas such as H ₂ so that the dichlorosilane concentration becomes 2.5%, for example, and supplied at 50 SLM, for example.

  Excess dichlorosilane, process gas including diluent gas, and reaction by-product such as HCl are discharged downward from the outer periphery of the susceptor 16. Further, these gases are discharged from the gas discharge mechanism 13 through the gas discharge port 13a, and the pressure in the reaction chamber 11 is controlled to be constant (for example, normal pressure). In this way, an Si epitaxial film is grown on the wafer w. After the Si epitaxial film having a desired film thickness is formed, the wafer w is unloaded from the reaction chamber 11.

  At this time, as shown in FIG. 3, the oily silane 31 produced | generated from gas, such as excess process gas, deposits on the inner wall and bottom face of the quartz liner 11b. Therefore, an oxidizing gas is supplied from the oxidizing gas supply mechanism 14 to the vicinity of the gas outlet 13a to oxidize the deposited oily silane, thereby generating a stable silicon oxide even in the atmosphere.

  At this time, the deposited oily silane reacts with oxygen on the surface and does not proceed inside. Therefore, in order to prevent unreacted oily silane from remaining, such an oxidizing gas supply process is preferably performed sequentially before a large amount of oily silane is deposited, and more preferably performed every film forming process. . It should be noted that the oxidizing gas needs to be sufficiently removed from the inside of the reaction chamber 11 in order to prevent the wafer w from being oxidized after the oxidizing gas is supplied and before the next film forming process is performed.

  The silicon oxide deposited on the inner wall and the bottom surface of the quartz liner 11b is combined with the normal reaction chamber 11 for removing other deposits (reaction byproducts) deposited in the reaction chamber 11, for example. Removed. At this time, the liner 11b can be separated and taken out and cleaned using a hydrofluoric acid aqueous solution or the like.

  According to the present embodiment, oily silane can be oxidized in advance and deposited as a stable silicon oxide even in the air, and then removed during normal decomposition maintenance. Therefore, the oily silane can be removed safely without reducing the throughput.

(Embodiment 2)
In the present embodiment, the configuration of the epitaxial film forming apparatus is the same as that of the first embodiment, but differs from the first embodiment in that the gap between the gas discharge port 13a and the quartz liner 11b provided on the inner wall is sealed. ing.

  FIG. 4 shows a cross-sectional view of the gas discharge port 13a in the epitaxial film forming apparatus which is the semiconductor manufacturing apparatus of the present embodiment. Although it is the same structure as Embodiment 1, it seals between the gas exhaust port 13a and the quartz liner 11b provided in the inner wall with the O-ring 41 which consists of silicones etc.

  With such a configuration, it is possible to suppress the generation of oily silane by the entry of excess process gas or the like into the gap between the gas discharge port 13a and the quartz liner 11b provided on the inner wall thereof. Become. In addition, when the quartz liner 11b is removed from the gas discharge port 13a in the atmosphere, it is possible to suppress the unreacted oily silane from reacting with moisture in the atmosphere explosively.

  According to the present embodiment, the same action as that of the first embodiment enables further safe removal of oily silane by reducing the remaining unreacted oily silane without lowering the throughput.

  According to these embodiments, it is possible to perform maintenance safely in a semiconductor manufacturing apparatus that forms a high-quality film such as an epitaxial film on a semiconductor wafer. In addition, even if safety is improved, throughput is not reduced, and high productivity can be obtained in a semiconductor wafer and a semiconductor device formed through an element formation process and an element isolation process. Become.

  In particular, it is suitable as an epitaxial film forming apparatus for forming power semiconductor devices such as power MOSFETs and IGBTs that require thick film growth of 40 μm or more in an N-type base region, a P-type base region, an insulating isolation region, etc. Can be used.

In these embodiments, the case of forming a Si single crystal layer (epitaxial film) has been described. However, the present embodiment can also be applied when forming a poly-Si layer. Further, the present invention can also be applied to film formation other than Si film such as SiO ₂ film and Si ₃ N ₄ film, and compound semiconductor such as GaAs layer, GaAlAs and InGaAs.

  Various other modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 11, 21 ... Reaction chamber 12 ... Gas supply mechanism 12a ... Gas supply port 13, 23 ... Gas discharge mechanism 13a, 23a ... Gas discharge port 14 ... Oxidative gas supply mechanism 14a ... Oxidative gas supply port 15 ... Rectification plate 16 ... Susceptor 17 ... Ring 18 ... Rotary drive control mechanism 19 ... Heater 31 ... Oily silane 41 ... O-ring

Claims (5)

A reaction chamber into which the wafer is introduced;
A process gas supply mechanism for supplying a process gas to the reaction chamber;
A wafer support member for mounting the wafer;
A heater for heating the wafer to a predetermined temperature;
A rotational drive control mechanism for rotating the wafer;
A gas discharge mechanism including an exhaust port for discharging gas from the reaction chamber;
Corresponding to the exhaust port, an oxidizing gas supply port provided above the exhaust port and below the horizontal position of the wafer support member is included, and the wafer is unloaded from the reaction chamber after the film formation process. each that, to the exhaust port Oirishira on emissions deposited on the silicon oxide at the top, and an oxidizing gas supply mechanism for supplying an oxidizing gas from the oxidizing gas supply port,
A semiconductor manufacturing apparatus comprising:   The semiconductor manufacturing apparatus according to claim 1, wherein a liner made of quartz is provided on an inner wall of the reaction chamber above the exhaust port. The semiconductor manufacturing apparatus according to claim 2 , wherein a gap between the inner wall and the liner is sealed. Wafer is introduced into the reaction chamber and held in place,
Heating the wafer at a predetermined temperature;
By rotating the wafer and supplying a process gas containing Si source gas on the wafer, a film is formed on the wafer,
Unloading the wafer on which the film formation process has been performed from the reaction chamber;
Each time unloading the wafer, on oily silane deposited on a silicon oxide in exhaust port top, supplying an oxidizing gas from below said predetermined position,
The semiconductor manufacturing method, wherein the oxidizing gas is removed from the reaction chamber before the next film forming process is performed on another wafer . After repeating a predetermined period a series of steps from the introduction of the wafer into the reaction chamber to the supply of the oxidation gas onto the oily silane, removing deposits including silicon oxide from the reaction chamber The semiconductor manufacturing method according to claim 4.

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