JP5252896B2 - Vapor growth apparatus and vapor growth method - Google Patents

Description

  The present invention relates to a vapor phase growth apparatus and a vapor phase growth method, and for example, relates to an apparatus and a method for epitaxial growth on a substrate.

  In the manufacture of semiconductor devices such as ultrahigh-speed bipolar and ultrahigh-speed CMOS, single crystal epitaxial growth technology with controlled impurity concentration and film thickness is indispensable for improving device performance.

  In general, an atmospheric pressure chemical vapor deposition method is used for epitaxial growth of a single crystal thin film on a semiconductor substrate such as a silicon wafer, and a low pressure chemical vapor deposition (LP-CVD) method is used in some cases. ing. A semiconductor substrate such as a silicon wafer is disposed in a chamber serving as a reaction vessel, and the semiconductor substrate is heated in a state where the inside of the reaction vessel is maintained in a normal pressure (0.1 MPa (760 Torr)) atmosphere or a vacuum atmosphere of a predetermined degree of vacuum. Then, a source gas containing a silicon source and a dopant such as a boron compound, an arsenic compound, or a phosphorus compound is supplied while rotating. A silicon epitaxial film doped with boron (B), phosphorus (P), or arsenic (As) is grown by thermal decomposition or hydrogen reduction reaction of the silicon source gas on the surface of the heated semiconductor substrate. (For example, refer to Patent Document 1).

  Epitaxial growth technology is also used in the manufacture of power semiconductors, for example, the manufacture of IGBTs (insulated gate bipolar transistors). In a power semiconductor such as IGBT, for example, a silicon (Si) epitaxial film having a thickness of several tens of μm or more is required.

Here, a board | substrate is arrange | positioned on the support surface of a holder (support member). When the Si epitaxial film is formed in this state, the source gas enters the back side of the substrate, and the Si epitaxial film is also formed on the back side of the substrate. Therefore, the problem that a board | substrate will stick to a holder has arisen. If the substrate adheres to the holder, the substrate will be damaged and the yield will be reduced. Therefore, in order to improve productivity, it is required to suppress sticking between the substrate and the support member.
JP-A-9-194296

  As described above, it is required to suppress sticking between the substrate and the support member. However, the conventional technique has not established a method for sufficiently suppressing the sticking between the substrate and the support member.

  Accordingly, an object of the present invention is to provide a vapor phase growth apparatus and method capable of overcoming such problems and suppressing sticking between a substrate and a support member.

The vapor phase growth apparatus of one embodiment of the present invention includes:
A support member for supporting the substrate;
A chamber in which a support member is disposed and a silicon (Si) -containing film is formed on the substrate;
An HCl gas supply section for supplying hydrogen chloride (HCl) gas toward the substrate from the back side of the substrate;
A heat source for heating the substrate from the processed surface side of the substrate;
It is provided with.

  Heating is performed from the processed surface side, not from the back surface side of the substrate. As a result, heating of the support member located on the back side of the substrate can be suppressed. Therefore, the growth rate of the Si-containing film formed on the back side of the substrate can be suppressed. Even if the Si-containing film is formed on the back side of the substrate, it can be reacted with the Si-containing film formed on the back side of the substrate by supplying HCl gas toward the substrate. As a result, the Si-containing film formed on the back side of the substrate can be etched.

  The support member is preferably rotated about the approximate center of the substrate surface.

The vapor phase growth apparatus further includes
A source gas supply unit that supplies a source gas for forming a Si-containing film from the processed surface side of the substrate toward the substrate,
As the heat source, it is preferable to use light having a wavelength that is not absorbed by the source gas supply unit.
In addition, the HCl gas is supplied to a contact position that contacts the outer peripheral portion of the back surface of the substrate and the lower surface of the opening along the circumferential direction of the outer peripheral portion, and the back surface of the substrate outside the contact position The Si-containing film formed between the lower surface of the opening is etched with the HCl gas.

The vapor phase growth method of one embodiment of the present invention includes:
In the chamber, the substrate is dug into the support member vertically or at a predetermined angle from the upper surface side to a predetermined depth, and the lower surface of the opening of the support member, the outer peripheral portion of the back surface of the substrate and the outer peripheral portion of the substrate A step of forming a silicon (Si) -containing film on the substrate using a source gas in a state of being supported in contact along the circumferential direction ;
Supplying a hydrogen chloride (HCl) gas from the back side of the substrate toward the substrate in a state where the substrate is supported by the support member when the substrate is formed;
A step of heating the substrate from the processed surface side of the substrate when the substrate is formed;
Equipped with a,
The support member is rotated about the approximate center of the substrate surface,
A source gas for forming the Si-containing film is supplied from the processed surface side of the substrate toward the substrate,
As a heat source for heating the substrate, light having a wavelength that the source gas supply unit does not absorb,
Supplying the HCl gas to a contact position in contact with the outer peripheral portion of the back surface of the substrate and the lower surface of the opening along the circumferential direction of the outer peripheral portion; and the back surface of the substrate outside the contact position and the A Si-containing film formed between the lower surface of the opening is etched with the HCl gas .

  When the Si epitaxial film is formed on the substrate, it is preferable to use the apparatus and method described above.

  According to the present invention, since the Si-containing film formed on the back side of the substrate can be etched, sticking between the substrate and the support member can be suppressed. As a result, productivity can be improved.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram showing the configuration of the epitaxial growth apparatus in the first embodiment.
In FIG. 1, an epitaxial growth apparatus 100 as an example of a vapor phase growth apparatus includes a holder (also referred to as a susceptor) 110 as an example of a support base, a chamber 120, a shower head 130, a vacuum pump 140, a pressure control valve 142, and wafer heating. A source 150, a supply unit 160, and a rotating member 170 are provided. In the chamber 120, the shower head 130, the holder 110, the supply unit 160, and a part of the rotating member 170 are arranged. The rotating member 170 extends from the chamber 120 to the rotating mechanism (not shown) outside the chamber 120. The chamber 120 is connected with a pipe serving as a flow path 122 for supplying gas and a pipe serving as a flow path 124 for exhausting gas. The flow path 122 is connected to the shower head 130 in the chamber 120. The shower head 130 or the flow path 122 is an example of the source gas supply unit. The supply unit 160 is an example of an HCl gas supply unit. FIG. 1 illustrates a configuration necessary for describing the first embodiment. However, the scale and the like are not the same as the actual product (hereinafter the same in each drawing).

  The holder 110 is formed with an opening 114 having a predetermined inner diameter. Then, the silicon wafer 101 is supported by coming into contact with the back surface of the silicon wafer 101 (substrate) at the lower surface of the opening 116 dug up to a predetermined depth perpendicularly or at a predetermined angle from the upper surface side. Further, the holder 110 has a circular outer periphery. And it arrange | positions on the rotation member 170 rotated with the approximate center line of the silicon wafer 101 surface orthogonal to the silicon wafer 101 surface as an axis | shaft by the rotation mechanism which is not shown in figure. The holder 110 can rotate the silicon wafer 101 together with the rotating member 170 by rotating about the substantially center line of the surface of the silicon wafer 101.

  Further, on the back side of the holder 110 and the silicon wafer 101, a supply unit 160 that extends through the inside of the rotating member 170 to the vicinity of the back side of the silicon wafer 101 is disposed. A wafer heating source 150 (heat source) is disposed outside the chamber 120. The wafer heating source 150 is disposed on the upper surface of the chamber 120 and heats the silicon wafer 101 from the upper surface side that is the processing surface of the silicon wafer 101. The temperature of the silicon wafer 101 is preferably heated to about 1100 ° C. As the wafer heating source 150, for example, a lamp heater is suitable. Further, a heater that emits light having a wavelength that is not absorbed by the material of the shower head 130 is suitable. For example, when the material of the shower head 130 is made of quartz or the like, it is preferable to use light having a wavelength of about 1 μm. Since the wafer heating source 150 is disposed outside the chamber 120, the shower head 130 is disposed between the wafer heating source 150 and the silicon wafer 101. However, since the shower head 130 is not heated, the film formation reaction inside the shower head 130 is performed. Can be suppressed.

  Then, the inside of the chamber 120 serving as a reaction vessel is maintained at a normal pressure or a vacuum atmosphere with a predetermined degree of vacuum by the vacuum pump 140. In this state, the silicon wafer 101 is heated by the wafer heating source 150. Then, by rotating the holder 110, the silicon wafer 101 supported by the holder 110 is rotated at a predetermined rotational speed. Then, a source gas serving as a silicon source is supplied from the shower head 130 into the chamber 120 while rotating. Thus, the wafer heating source 150 heats the silicon wafer 101 from the processed surface side of the silicon wafer 101 when the silicon wafer 101 is formed. When the raw material gas at normal temperature reaches the silicon wafer 101, thermal decomposition or hydrogen reduction is performed by the heat of the silicon wafer 101 heated by the wafer heating source 150. As a result, a silicon epitaxial film as an example of a Si-containing film is formed on the surface of the silicon wafer 101.

  Further, the pressure in the chamber 120 may be adjusted to a normal pressure or a vacuum atmosphere with a predetermined degree of vacuum using the pressure control valve 142, for example. Alternatively, when used at normal pressure, a configuration without the vacuum pump 140 or the pressure control valve 142 may be used. In the shower head 130, the source gas supplied from the outside of the chamber 120 through a pipe is discharged from a plurality of through holes through a buffer inside the shower head 130. Therefore, the source gas can be uniformly supplied onto the silicon wafer 101.

  Here, in the first embodiment, when the silicon wafer 101 is formed, HCl gas is supplied from the supply unit 160 disposed on the back side of the silicon wafer 101 while the silicon wafer 101 is supported by the holder 110. Supply toward the silicon wafer 101. Thereby, it can be made to react with the silicon epitaxial film formed on the back side of the substrate. As a result, the silicon epitaxial film formed on the back side of the substrate can be etched.

  Then, the gas after the silicon epitaxial film formation process is exhausted from the chamber 120 through the flow path 124. Further, HCl gas that has flowed from the back surface side of the silicon wafer 101 through the gap between the silicon wafer 101 and the holder 110 and gas after reaction between the HCl gas and the silicon epitaxial film are exhausted from the chamber 120 through the flow path 124. Is done. Here, the inside of the chamber 120 is evacuated by the vacuum pump 140, but is not limited thereto. Any device that can exhaust the inside of the chamber 120 may be used. For example, if a normal atmosphere or a vacuum atmosphere close to normal pressure is acceptable, the air may be exhausted with a blower or the like.

FIG. 2 is a diagram showing an example of the appearance of the epitaxial growth apparatus system in the first embodiment.
As shown in FIG. 2, the epitaxial growth apparatus system 300 is entirely surrounded by a casing.
FIG. 3 is a diagram showing an example of a unit configuration of the epitaxial growth apparatus system in the first embodiment.
In the epitaxial growth apparatus system 300, the cassette is disposed on the cassette stage (C / S) 310 or the cassette stage (C / S) 312. Then, the silicon wafer 101 set in the cassette is transferred into the load lock (L / L) chamber 320 by the transfer robot 350. Then, the silicon wafer 101 is unloaded from the L / L chamber 320 into the transfer chamber 330 by the transfer robot 332 disposed in the transfer chamber 330. Then, the unloaded silicon wafer 101 is transferred into the chamber 120 of the epitaxial growth apparatus 100. Then, a silicon epitaxial film is formed on the surface of the silicon wafer 101 by the epitaxial growth method. The silicon wafer 101 on which the silicon epitaxial film is formed is again carried out from the epitaxial growth apparatus 100 into the transfer chamber 330 by the transfer robot 332. The unloaded silicon wafer 101 is transferred to the L / L chamber 320. Thereafter, the transfer robot 350 returns the cassette from the L / L chamber 320 to the cassette placed on the cassette stage (C / S) 310 or the cassette stage (C / S) 312. In the epitaxial growth apparatus system 300 shown in FIG. 3, two chambers 120 and two L / L chambers 320 of the epitaxial growth apparatus 100 are mounted. Thereby, throughput can be improved.

FIG. 4 is a diagram for explaining a gas flow and a film state in the first embodiment.
In FIG. 4, the source gas is supplied from above, which is the processing surface of the silicon wafer 101. As the source gas, for example, trichlorosilane (SiHCl ₃ ) gas or dichlorosilane (SiH ₂ Cl ₂ ) gas which is a Si source is suitable. Alternatively, these mixed gases are also suitable. Further, hydrogen (H ₂ ) gas is also mixed as a carrier gas. In addition, phosphine (hydrogen phosphide: PH ₃ ), diborane (borohydride: B ₂ H ₆ ), or the like may be mixed as a dopant gas. When these mixed gases reach the processed surface of the silicon wafer 101 heated by the wafer heating source 150, the silicon epitaxial film 10 is formed. Here, these source gases are deposited not only on the processed surface of the silicon wafer 101 but also on the back surface of the silicon wafer 101 and the upper surface of the holder 110. In particular, when the source gas flows around the back surface side of the silicon wafer 101, the silicon film 20 is formed in a gap between the back surface of the silicon wafer 101 and the holder 110. Therefore, the back surface of the silicon wafer 101 and the holder 110 are attached by the silicon film 20.

However, in Embodiment 1, HCl gas enters the gap between the back surface of the silicon wafer 101 and the holder 110 by supplying HCl gas toward the silicon wafer 101 from the back surface side of the silicon wafer 101. The silicon film 20 is etched by an etching reaction according to the following formula (1).
(1) Si + 3HCl → SiHCl ₃ + H ₂

  This reaction needs to be heated to, for example, about 900 ° C., but since the silicon wafer 101 is heated to about 1100 ° C. by the wafer heating source 150, the etching reaction can be sufficiently caused. Further, since both the silicon wafer 101 and the holder 110 are rotating at a high speed, the HCl gas is moved to the outer peripheral side along the back surface of the silicon wafer 101, that is, the contact position between the back surface of the silicon wafer 101 and the holder 110. Can be supplied to.

  As described above, by etching the silicon film 20 generated on the back surface of the silicon wafer 101, the back surface of the silicon wafer 101 and the holder 110 can be prevented from sticking.

FIG. 5 is a diagram for explaining suppression of sticking of a silicon wafer due to a difference in heating direction in the first embodiment.
As shown in FIG. 5A, when the back surface of the silicon wafer 101 is heated by the heater 152 from the back surface side of the silicon wafer 101, the silicon wafer 101 warps convexly toward the back surface side. In this case, the contact position between the silicon wafer 101 and the holder 110 moves to the center side, so that a gap between the back surface of the silicon wafer 101 and the holder 110 is widened. Therefore, since the source gas easily enters the gap between the expanded back surface of the silicon wafer 101 and the holder 110, Si growth is more likely to occur. On the other hand, as shown in FIG. 5B, when the upper surface of the silicon wafer 101 is heated by the wafer heating source 150 from the upper surface (processed surface) side of the silicon wafer 101, the silicon wafer 101 warps convexly toward the upper surface side. Become. In that case, the gap between the back surface of the silicon wafer 101 and the holder 110 is reduced by moving the contact position between the silicon wafer 101 and the holder 110 to the outer peripheral side. For this reason, the source gas is less likely to enter the gap between the back surface of the silicon wafer 101 and the holder 110, so that Si growth can be further prevented.

  5A, when the back surface of the silicon wafer 101 is heated by the heater 152 from the back surface side of the silicon wafer 101, the holder 110 is also directly heated. When the holder 110 is heated, the Si growth rate of the source gas that has entered the gap between the back surface of the silicon wafer 101 and the holder 110 is increased. On the other hand, as shown in FIG. 5B, even if the upper surface of the silicon wafer 101 is heated by the wafer heating source 150 from the upper surface (processed surface) side of the silicon wafer 101, the gap between the back surface of the silicon wafer 101 and the holder 110 is maintained. Since this gap is not directly heated, Si growth of the source gas that has entered the gap can be suppressed as compared with the case of heating from the back side.

  As described above, heating of the holder 110 located on the back surface side of the silicon wafer 101 can be suppressed by heating from the processing surface side instead of from the back surface side of the silicon wafer 101. Therefore, the growth rate of the Si-containing film formed on the back side of the silicon wafer 101 can be suppressed. And even if the Si-containing film is formed on the back surface side of the silicon wafer 101, the HCl gas is supplied toward the substrate to react with the Si-containing film formed on the back surface side of the silicon wafer 101. Can do. As a result, the Si-containing film formed on the back side of the silicon wafer 101 can be etched. Therefore, sticking of the silicon wafer 101 and the holder 110 can be suppressed. As a result, productivity can be improved.

  The effect of the first embodiment can be exhibited more particularly when it is used for thick epitaxial growth. For example, it is suitable for use in epitaxial growth of 60 μm or more.

  Of course, not only IGBTs, but also power semiconductors that require high breakdown voltage, power MOSs, GTOs (gate turn-off thyristors) and general thyristors (SCRs) that are used as switching elements for trains and the like. It can be applied to the formation of an epitaxial layer with a thick base.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, although an epitaxial growth apparatus has been described as an example of a vapor phase growth apparatus, the present invention is not limited to this, and any apparatus for vapor phase growth of a Si film on a sample surface may be used. For example, an apparatus for growing a polysilicon film may be used.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the epitaxial growth apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all vapor phase growth apparatuses and vapor phase growth methods that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

1 is a conceptual diagram showing a configuration of an epitaxial growth apparatus in a first embodiment. It is a figure which shows an example of the external appearance of an epitaxial growth apparatus system. It is a figure which shows an example of a unit structure of an epitaxial growth apparatus system. FIG. 3 is a diagram for explaining a gas flow and a film state in the first embodiment. 6 is a diagram for explaining suppression of sticking of a silicon wafer due to a difference in heating direction in the first embodiment. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Silicon epitaxial film 20 Silicon film 100 Epitaxial growth apparatus 101 Silicon wafer 110 Holder 114, 116 Opening part 120 Chamber 122, 124 Flow path 130 Shower head 140 Vacuum pump 142 Pressure control valve 150 Wafer heating source 160 Supply part 170 Rotating member 300 Epitaxial growth apparatus System 310, 312 Cassette stage 320 L / L chamber 330 Transfer chamber 332, 350 Transfer robot

Claims (3)

A supporting member that supports the substrate by contacting the outer peripheral portion of the back surface of the substrate along the circumferential direction of the outer peripheral portion at the lower surface of the opening vertically or at a predetermined angle from the upper surface side to a predetermined depth ; ,
A chamber in which the support member is disposed and a silicon (Si) -containing film is formed on the substrate;
An HCl gas supply section for supplying hydrogen chloride (HCl) gas toward the substrate from the back side of the substrate;
A heat source for heating the substrate from the processed surface side of the substrate;
Equipped with a,
The support member is rotated about the approximate center of the substrate surface,
A source gas supply unit for supplying a source gas for forming the Si-containing film from the processed surface side of the substrate toward the substrate;
The heat source uses light of a wavelength that the source gas supply unit does not absorb,
Supplying the HCl gas to a contact position in contact with the outer peripheral portion of the back surface of the substrate and the lower surface of the opening along the circumferential direction of the outer peripheral portion; and the back surface of the substrate outside the contact position and the A vapor phase growth apparatus characterized by etching a Si-containing film formed between a lower surface of an opening with the HCl gas . In the chamber, the substrate is dug into the support member vertically or at a predetermined angle from the upper surface side to a predetermined depth, and the lower surface of the opening of the support member, the outer peripheral portion of the back surface of the substrate and the outer peripheral portion of the substrate A step of forming a silicon (Si) -containing film on the substrate using a source gas in a state of being supported in contact along the circumferential direction ;
Supplying the hydrogen chloride (HCl) gas toward the substrate from the back side of the substrate in a state where the substrate is supported by the support member when the substrate is formed;
Heating the substrate from the processed surface side of the substrate when the substrate is formed;
Equipped with a,
The support member is rotated about the approximate center of the substrate surface,
A source gas for forming the Si-containing film is supplied from the processed surface side of the substrate toward the substrate,
As a heat source for heating the substrate, light having a wavelength that the source gas supply unit does not absorb,
Supplying the HCl gas to a contact position in contact with the outer peripheral portion of the back surface of the substrate and the lower surface of the opening along the circumferential direction of the outer peripheral portion; and the back surface of the substrate outside the contact position and the A vapor phase growth method characterized by etching a Si-containing film formed between a lower surface of an opening with the HCl gas . 3. The vapor phase growth method according to claim 2 , wherein a Si epitaxial film is formed on the substrate.

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