TWI658169B - Gas phase deposition apparatus and method of gas phase deposition - Google Patents

Abstract

The invention provides a vapor phase growth device and a vapor phase growth method. The vapor phase growth device includes a holder for placing a substrate (such as a silicon wafer) therein. The holder has a plurality of ejector holes at the bottom. The vapor growth device further includes a plurality of ejector rods that can be raised and lowered along the ejector rod hole, and a hollow channel for introducing a purge gas is formed in the ejector rod. In addition, the vapor growth device further includes A first air inlet for the process gas and a second air inlet for the purge gas. During the vapor phase growth process, the hollow channel communicates with the ejector pin hole, and a purge gas is passed into the hollow channel in the ejector pin. The purge gas blocks other gases near the ejector pin hole, such as process gas. Effect, thereby reducing or preventing the process gas from reaching the back surface of the substrate from the gap between the pin hole and the pin, which can improve the flatness of, for example, an epitaxial wafer obtained by vapor phase growth.

Description

Vapor phase growth device and gas phase growth method

The invention relates to the field of semiconductors, in particular to a vapor phase growth device and a vapor phase growth method.

In recent years, epitaxial (epitaxial) layers are formed on the surface of a substrate, such as a wafer, and are widely used in the manufacturing process of MOS (Metal Oxide Semiconductor) elements. These epitaxial wafers improve the yield of gate oxide layers of MOS devices and have superior characteristics such as reducing parasitic capacitance, preventing soft errors, improving gettering performance, and improving mechanical strength.

In recent years, epitaxial growth equipment capable of performing an epitaxial growth process on a silicon wafer having a diameter of 300 mm or more has been developed. Moreover, in order to maximize the use of epitaxial wafers, epitaxial wafers are required to have very flat and parallel surfaces (front and back parallel to each other). With the decrease of the critical dimension (CD) of the integrated circuit process, the nano-morphology of the epitaxial wafer before patterning becomes more and more important in the fabrication of integrated circuits.

One method of growing an epitaxial layer on a silicon wafer is a vapor phase growth method, which uses a process gas to perform a gas phase reaction on the silicon wafer to grow an epitaxial layer. However, the applicant's research found that the flatness of the epitaxial wafer is not satisfactory after the vapor phase growth using the conventional vapor phase growth device.

The purpose of the present invention is to solve the problem of poor flatness of an epitaxial wafer.

To achieve the above object, in one aspect, the present invention provides a vapor phase growth apparatus. The vapor growth device includes the following structure: a holder including a bottom portion and a side portion surrounding the bottom portion, the bottom portion and the side portion defining a pit for placing a substrate, and the holder is further formed on the holder. There are a plurality of ejector holes penetrating through the bottom; the ejector rod can be raised and lowered along the ejector hole and has a lowest position, the ejector rod is formed with a hollow channel for introducing purge gas; A first air inlet for a process gas; and a second air inlet for passing a purge gas, said purge gas being passed through the second air inlet and the hollow channel to the ejector hole Inside.

Optionally, the hollow channel includes a first hollow channel and a plurality of second hollow channels, the first hollow channel extends along an axial direction of the ejector rod, and the plurality of second hollow channels and the first hollow channel The hollow channel is communicated, and the openings of the plurality of second hollow channels face the side wall of the ejector hole when the ejector is at the lowest position.

Optionally, a plurality of the second hollow channels are uniformly distributed radially with the first hollow channel as a center. A plurality of the second hollow channels are distributed on the same horizontal plane. The second hollow channel is a strip-shaped straight hole or an arc-shaped hole.

Optionally, the vapor phase growth device further includes an exhaust port for exhausting gas to the outside of the vapor phase growth device.

Optionally, the gas phase growth device further includes a guide pipe, and the purge gas passes through The guide channel opens into the hollow channel.

In another aspect, the present invention also provides a vapor phase growth method using the above-mentioned vapor phase growth device, including the steps of: placing a substrate in the receiver; The growth device passes in a process gas for forming a predetermined film layer on the substrate, and a purge gas is introduced into the ejector hole through the second air inlet and the hollow channel.

Optionally, the purge gas is passed into the first hollow channel at a pressure ranging from 20 PSI to 50 PSI.

Optionally, the process gas includes a source gas and a carrier gas. The purge gas is the same gas as the carrier gas.

Optionally, the process gas and the purge gas are simultaneously introduced. After stopping the introduction of the process gas, the purge gas continues to be introduced for a predetermined time.

By using the vapor phase growth device and the vapor phase growth method provided by the present invention, during the vapor phase growth process, the ejector rod is at the lowest position, and the first surface of the substrate, such as a wafer, is passed through the first air inlet to the upper surface of the substrate. When the process gas for vapor phase growth is introduced, the purge gas is additionally passed through the hollow channel in the ejector pin into the ejector pin hole through a second air inlet, and the purge gas has a purge effect on the ejector pin hole. In this way, the process gas flowing from the gap between the ejector pin hole and the ejector pin to the back of the wafer is blocked away. By using the vapor phase growth device and the vapor phase growth method provided by the present invention, the flatness of, for example, an epitaxial wafer formed by vapor phase growth can be improved.

1‧‧‧ center shaft

2‧‧‧ support arm

3‧‧‧ Area near the ejector hole

10‧‧‧ Reaction Room

11‧‧‧ Receiver

11a‧‧‧Bottom of the receiver

11b‧‧‧side of receiver

12‧‧‧ ejector hole

13‧‧‧ Jack

14‧‧‧Heating device

15‧‧‧air inlet

16‧‧‧ exhaust port

20‧‧‧process gas

21‧‧‧ purge gas

100‧‧‧Chip

100a‧‧‧ front of the chip

100b‧‧‧Chip back

101‧‧‧Epitaxial layer

102‧‧‧ Top shot

30‧‧‧Reaction Room

31‧‧‧ Acceptor

31a‧‧‧Bottom of the receiver

31b‧‧‧side of receiver

31c‧‧‧Bearer support

32‧‧‧ ejector hole

33‧‧‧ Jack

34‧‧‧Heating device

35‧‧‧first air inlet

36‧‧‧ exhaust port

37‧‧‧Second air inlet

300‧‧‧Chip

300a‧‧‧ wafer top surface

300b‧‧‧Chip lower surface

301‧‧‧Epitaxial layer

330‧‧‧hollow channel

332‧‧‧First hollow channel

333‧‧‧Second hollow channel

331‧‧‧Entrance

FIG. 1 is a schematic cross-sectional view of a vapor growth device.

FIG. 2 is a schematic cross-sectional view of a vapor growth device according to an embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of the area near the ejector hole in FIG. 2.

FIG. 4 is a schematic top plan view of the ejector rod of the vapor phase growth apparatus according to the embodiment of the present invention from the substrate direction in FIG. 2.

In the following, a susceptor and a vapor phase growth method for vapor phase growth according to the present invention will be further described in detail with reference to the drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the present invention is not limited to the following embodiments at all. In addition, the drawings are in a very simplified form and all use inaccurate proportions, which are only used to facilitate and clearly explain the purpose of the embodiments of the present invention.

The terms "first", "second", and the like in the description and the claims are used to distinguish between similar elements, and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms so used may be substituted, for example, to enable embodiments of the invention described herein to operate differently from other sequences described or shown herein. Similarly, if the method described herein includes a series of steps, and the order of the steps presented herein is not necessarily the only order in which these steps can be performed, and some of the described steps may be omitted and / or some are not described herein Additional steps can be added to the method. If the components of the embodiment of the present invention in the figure are the same as those in the other figures, although these members can be easily identified in all the figures, in order to make the description of the figure clearer, this specification will not make all the same. The numbers of the components are marked in each figure.

FIG. 1 is a schematic cross-sectional view of a vapor phase growth device. The substrate is transferred by means of a lift pin. The substrate is, for example, a wafer 100. The vapor phase growth apparatus includes a reaction chamber 10, and a receiver 11 is installed in the reaction chamber 10. The receiver 11 has a bottom portion 11a and a side portion 11b. The bottom portion 11a and the side portion 11b together define a wafer 100 for placing the wafer 100 thereon. The wafer 100 to be vapor-grown is placed in the cavity, and the wafer 100 has a front surface 100a to be vapor-grown and a back surface 100b opposite thereto. In addition, the holder 11 is provided with a plurality of ejector rod holes 12 penetrating the bottom portion 11a, and a plurality of ejector rods 13 provided in the reaction chamber 10 pass through the ejector rod holes 12 and may be perpendicular to the bottom portion 11a. Lift in the plane direction (that is, ascend or descend).

During the vapor phase growth process, the holder 11 and the wafer 100 are heated and maintained at a certain temperature by two heating devices 14 located at the upper and lower portions of the reaction chamber 10, and the process is introduced into the reaction chamber 10 from the air inlet 15 The gas 20 is supplied to the upper surface 100a of the wafer 100, and the process gas 20 decomposed due to the high temperature is accumulated on the upper surface 100a of the wafer 100 and is vapor-grown. After the vapor-phase growth is completed, the wafer 100 is formed on the surface 100a of the wafer 100 With an epitaxial layer 101 of a predetermined thickness, the remaining gas is discharged to the outside of the reaction chamber 10 through the exhaust port 16.

The applicant's research found that in the process of vapor phase growth using the vapor phase growth device shown in FIG. 1, the process gas 20 entering the reaction chamber 10 from the air inlet 15 (as shown by the dashed solid arrow in FIG. 1) ), Due to the negative pressure, it will flow to the lower surface side of the pit of the susceptor 11 through the gap between the reaction chamber 10 and the susceptor 11 (as shown by the thick dashed solid arrow in FIG. 1). There is a gap between the ejector pin hole 12 and the ejector pin 13 on the holder 11, and the process gas 20 flowing to the lower surface side of the pit of the holder 11 will reach the back surface 100b of the wafer 100 from this gap. At a certain temperature, Deposit a tube-like rod on the back surface 100b of the wafer 100 corresponding to the rod hole 12, especially the gap between the rod hole 12 and the rod 13. Spot 102 (pin mark). These ejector pins 102 formed on the back surface 100b of the wafer 100 will destroy the nano-morphology of the back surface 100b of the wafer 100 and deteriorate the overall morphology of the formed epitaxial wafer.

The inventor used a wafer geometry measurement system (KLAWaferSight) to measure the SFQR (Site flatness front least-squares range) of the front side of the epitaxial wafer obtained using the vapor growth device shown in FIG. It is used to evaluate the flatness of the wafer. The study found that the SFQR value is relatively large corresponding to the position of the ejector hole on the back side, resulting in poor flatness of the entire epitaxial wafer.

Based on the above research, this embodiment provides a vapor growth device and a vapor growth method. The vapor growth device includes a jack that can be raised and lowered along the jack hole and has a lowest position. When a purge gas is introduced into the hollow channel, a process gas is introduced into the substrate (wafer 300 in this embodiment) through a first air inlet on the vapor growth device to a surface of a predetermined film layer to be vapor grown, In addition, the purge gas is passed into the corresponding ejector hole through the hollow channel through the second air inlet. The purge gas entering the hollow channel has a purge effect on the interior of the ejector hole. If the process gas under the device is to flow from the gap between the ejector pin hole and the ejector pin to the back of the substrate, it will be blocked by the purge gas blown out from the hollow channel into the ejector pin hole, so the process gas can be reduced or avoided. The problem of forming pinned spots on the back surface of a wafer. By using the vapor phase growth device and the vapor phase growth method provided by the present invention, the flatness of, for example, an epitaxial wafer formed by vapor phase growth can be improved.

The following describes in detail a vapor phase growth apparatus according to an embodiment of the present invention with reference to FIG. 2.

FIG. 2 is a schematic cross-sectional view of a vapor growth device according to an embodiment of the present invention. The vapor growth device performs substrate transfer by means of a lift pin. As shown in FIG. 2, the vapor phase growth apparatus includes a reaction chamber 30. The holder 31 is placed in the reaction chamber 30 for placing a substrate. In this embodiment, the substrate is a wafer 300. The holder 31 includes a bottom portion 31 a and a side portion 31 b surrounding the bottom portion 31 a. The side portion 31 b and the bottom portion 31 a together define a recess for forming the wafer 300.

Since the susceptor 31 (specifically, the lower edge portion of the side portion 31b thereof in this embodiment) is engaged with the support arm 2 connected to the central rotating shaft 1, the central rotating shaft 1 can be driven to rotate, thereby driving the susceptor 31 in the gas phase growth process. Medium can be rotated.

In addition, a support portion 31c is formed on the holder 31 to support and / or restrain the semiconductor wafer 300 through surface contact, line contact, or point contact with the periphery of the wafer 300. In this embodiment, the support portion 31c is located between the bottom portion 31a and the side portion 31b of the receiver 31, and is formed by the side portion 31b extending in the direction of the bottom portion 31a, and has a step shape. Those skilled in the art should understand that the support portion 31c may also be provided with a limited position component, such as a card position device or a bead, to fix the wafer 300 in the recess of the holder 31 and restrict its movement to prevent The position of the wafer 300 is changed by the gas flow during the vapor phase growth process, but the present invention is not limited thereto.

The wafer 300 placed on the dent-shaped holder 31 has an upper surface 300a to be formed with an epitaxial layer 301 and a lower surface 300b opposite to the upper surface 300a, wherein the lower surface 300b is close to the bottom 31a The upper surface 300a faces away from the bottom 31a.

The invention does not limit the type of the wafer 300. For example, a silicon wafer, a gallium arsenide wafer, an SOI (silicon on insulator) wafer, or a selectively grown epitaxial wafer can be used. In this embodiment, the wafer 300 used is, for example, a P-type silicon circular single wafer with a diameter of 200 mm or 300 mm.

The size of the susceptor 31 may be changed in an appropriate manner according to the diameter of the wafer 300. For example, after the susceptor 31 places the wafer 300, it is preferable that the outer edge and the side of the wafer 300 There is a gap of approximately 1-10 mm between the inner edges of 31b. The difference in height between the upper surface of the support portion 31 c and the upper surface of the side portion 31 b is substantially the same as the thickness of the wafer 300.

In addition, in general, only one semiconductor wafer 300 is placed corresponding to one holder 31, and the wafer 300 placed on the holder 31 is transferred by at least three ejectors 33. The bottom 31a of the receiver 31 is formed with jack holes 32 corresponding to the number of jacks 33. The jack holes 32 are uniformly distributed in the plane of the bottom 31a, for example, and are arranged at intervals of 120 degrees in this embodiment. A plurality of ejectors 33 can be lifted and lowered in the ejector holes 32 at substantially the same time and the same amplitude. When the ejectors 33 rise in the ejector holes 32, they contact the lower surface 300b of the wafer 300 to support the wafer 300. The operation of lifting or placing on the receiver 31 is performed. In order to make the ejector pin 33 move smoothly within the ejector pin hole 32, the diameter of the ejector pin hole 32 is larger than the diameter of the ejector pin 33, so that there is a gap between the ejector pin hole 32 and the ejector pin 33.

What needs to be explained here is that the ejector rod 33 can perform lifting movement in the ejector hole 32, and during the vapor phase growth process, the ejector rod 33 is at the lowest position within its lifting range. In this lowest position, a portion of the ejector pin 33 near the upper part projects into the ejector hole 32, as shown in FIG. 2. This embodiment mainly describes the case of the vapor phase growth device when the ejector pin 33 is in the vapor phase growth process, that is, the lowest position (the same applies hereinafter).

The reaction chamber 30 is provided with a heating device 34 for heating the holder 31 and the wafer 300. The heating device 34 may be a halogen lamp, an infrared lamp, or the like. The position and heating method of the heating device 34 can be a method known in the art, which is not limited in the present invention.

In addition, it should be noted that, in this embodiment, the vapor phase growth device should further include a transfer device (not shown) located outside the reaction chamber 30, so that the wafer 300 can be output or output from the reaction chamber 30. The reaction chamber 30 should include a Chamber door (not shown) that can be opened or closed to facilitate the description The transfer device feeds the wafer 300 into or out of the reaction chamber 30.

The reaction chamber 30 of the vapor-phase growth apparatus further includes a plurality of first air inlets 35 and a plurality of air outlets 36. In this embodiment, the reaction chamber 30 has a first air inlet 35 and an air outlet 36, and the first air inlet 35 and the air outlet 36 face each other and are located on the reaction chamber 30 and on the receiver 31. side. The first air inlet 35 is used to pass into the reaction chamber 30 a process gas 20 including a source gas and a carrier gas for forming an epitaxial layer 301. The source gas used to form the epitaxial layer 301 is, for example, a gas such as SiH ₄ , SiH ₂ Cl ₂ , SiHCl ₃ or SiCl ₄ , and H ₂ (hydrogen) or an inert gas can be used as a carrier gas. The function of diluting the source gas, the process gas 20 may further include a trace amount of dopant gas, such as B ₂ H ₄ . In this embodiment, the source gas is, for example, SiHCl ₃ (silicon trichlorohydrin, also known as TCS), and the carrier gas is, for example, H ₂ . The process gas 20 mixed with a small amount of dopants, which is mainly formed of a carrier gas and a source gas, is transported from the first air inlet 35 and is designed to flow parallel to the surface 300 a (in the horizontal direction) of the wafer 300. At a certain temperature, the provided process gas 20 passes through the surface 300a of the wafer 300 to grow the epitaxial layer 301, and is discharged to the outside of the reaction chamber 30 by the exhaust port 36. The first air inlet 35 and the exhaust port 36. It is also possible to select appropriate conditions for introducing or discharging gas according to the pressure requirements in the reaction chamber 30.

However, the inventors have found that if the circumvention is not carried out, the process gas 20 entering the reaction chamber 30 through the first air inlet 35 does not only flow horizontally above the surface 300 a of the wafer 300, but a part of the process gas 20 flows below the holder 31. Because there is a gap between the ejector hole 32 and the ejector pin 33, a part of the process gas 20 may flow upward from this gap and reach the back surface 300b of the wafer 300, and a deposition process similar to the vapor phase growth reaction of the front surface 300a occurs, resulting in a wafer The back surface 300b of the 300 corresponds to the position of the ejector hole 32 to form ejector spots.

For this reason, in this embodiment, a second air inlet 37 is provided on the air inlet side of the reaction chamber 30, and an inlet 331 is provided on the ejector rod 33. The inlet 331 and the second air inlet 37 pass, for example, through A guide pipe (not shown) is provided for connection, thereby forming a gas passage. The position of the entrance 331 may be set on the cross section of the ejector 33 below the receiver, or on the side surface of the ejector 33. The shape of the entrance 331 may be circular or square, but the present invention is not limited thereto.

In addition, in this embodiment, a hollow passage 330 is provided in the ejector pin 33. The hollow passage 330 communicates with the second air inlet 37 through the inlet 331 and a guide pipe (not shown), and the hollow passage 330 is on the side of the ejector pin 33. The opening is located in the ejector hole 32. The hollow channel 330 includes a first hollow channel 332 and a plurality of second hollow channels 333. The first hollow channel 332 extends along the axial direction of the ejector rod 33. In this embodiment, the first hollow channel 332 is located at the top. The interior of the rod 33, but does not completely penetrate the ejector rod 33, but communicates with the second hollow channel 333 whose opening faces the side wall of the ejector hole 32, and the first hollow channel 332 and the second hollow channel 333 are both Striped and perpendicular to each other. In other embodiments of the present invention, the first hollow channel 332 may also penetrate an end of the ejector pin 33 near the wafer 300, and communicate with the second hollow channel 333 whose opening faces the side wall of the ejector hole 32, or the first hollow The channel 332 and the second hollow channel 333 form an obtuse angle, but the present invention is not limited thereto.

FIG. 3 is a schematic cross-sectional view of the area 3 near the ejector hole 32 in FIG. 2.

In combination with FIG. 2 and FIG. 3, during the vapor phase growth process of the upper surface 300 a of the wafer 300, the process gas 20 flows through the upper surface 300 a of the wafer 300. In addition, part of the process gas 20 may also flow below the receiver 31. In this embodiment, the second air inlet 37 passes through a plurality of guide pipes (not shown), a plurality of inlets 331, a plurality of first hollow channels 332, and a plurality of second hollow channels 333 during the vapor phase growth process. Purge gas 21 is introduced into the plurality of ejector holes 32 (as shown in Fig. 2 and Fig. 2). As shown by the dashed hollow arrows in FIG. 3), the purge gas 21 blown out from the plurality of ejector holes 32 through the plurality of second hollow channels 333 forms an air flow in the ejector holes 32, especially including the The airflow in the plane direction of the bottom 31a acts as a barrier to the process gas 20 flowing upward from the gap between the lower ejector hole 32 and the ejector pin 33, and prevents the process gas 20 from reaching the back surface 300b of the wafer 300 through the gap.

As shown in FIG. 3, in this embodiment, the first hollow channel 332 coincides with the centerline of the axis of the ejector pin 33. In other embodiments of the present invention, the first hollow channel 332 may not be aligned with the axis of the ejector pin 33. The center lines coincide. The first hollow channel 332 may extend along a straight line or a spiral path along the axis of the ejector 33, and communicate with the ejector hole 32 through the second hollow channel 333. In addition, a plurality of second hollow channels 333 may also communicate. The arc-shaped holes of the first hollow channel 332 and the ejector hole 32, and the plurality of second hollow channels 333 may not be in the same horizontal plane, but the present invention is not limited thereto.

FIG. 4 is a schematic top plan view of the ejector pin 33 of a vapor phase growth apparatus according to an embodiment of the present invention from the substrate (wafer 300 in this embodiment) direction in FIG. 2. In this embodiment, there are eight second hollow channels 333 formed in one ejector rod 33 and communicating with the first hollow channel 332, and a plurality of the second hollow channels 333 are strip-shaped straight holes. The hollow channels 332 are uniformly distributed radially at the center. A plurality of the second hollow passages 333 are distributed on the same horizontal plane. As shown in FIG. 3 and FIG. 4, the second hollow passages 333 are perpendicular to the plane of the bottom 31 a of the receiver 31 and from the second hollow passages 332 to the ejector pin. The purge gas 21 sprayed from the hole 32 may be purged in multiple directions, thereby blocking the process gas 20 under the holder 31 from reaching the back surface 300 a of the wafer 300 from various directions.

This embodiment also introduces a method for vapor phase growth. Home.

As shown in Figures 2 and 3, the method includes:

In step 1, a substrate (wafer 300 in this embodiment) is placed on the holder 31.

Specifically, the wafer 300 is transferred to the inside of the reaction chamber 30 by using a transfer device (not shown) after pre-processing and vacuuming the reaction chamber 30 of the vapor growth device. In this embodiment, the wafer 300 is further placed by means of the ejector pin 33. For example, the ejector pin 33 is first raised, the wafer 300 placed on the transfer device is lifted, and then the transfer device is retracted, and the ejector pin 33 is lowered, and the wafer 300 is placed on the holder 31, but the present invention is not limited thereto.

In a preferred solution, a support portion 31c is further provided between the bottom portion 31a and the side portion 31b of the holder 31, for supporting and / or restricting the wafer through surface contact, line contact, or point contact with the periphery of the wafer 300. 300.

It should be pointed out that according to the specific vapor growth conditions and the characteristics of the wafer 300, other steps can be added before step 1, such as cleaning the surface of the holder 31 before transferring the wafer 300 into the reaction chamber 30. Or pre-process the wafer 300 according to the situation. In addition, if there is a protective film on the back surface 300b of the wafer 300, the protective film can be removed first and then vapor-phase growth can be performed. A baking process is performed at a high temperature.

In step 2, a process gas 20 for forming a predetermined film layer on the substrate (wafer 300 in this embodiment) is introduced into the reaction chamber 30 through the first air inlet 35, and through the second air inlet 37 and the hollow The channel 330 passes the purge gas 21 into the ejector hole 32.

The process gas 20 includes a source gas such as SiH ₄ , SiH ₂ Cl ₂ , SiHCl ₃ or SiCl ₄ , and a carrier gas for dilution function, such as H ₂ (hydrogen) or an inert gas. Miscellaneous gases. The process gas 20 formed by the mixed gas may enter the reaction chamber 30 from one first air inlet 35, or may enter the reaction chamber 30 by a plurality of first air inlets 35.

In this embodiment, the first gas inlet 35 leads into the reaction chamber 30 and is formed of a mixed gas in which a silicon source gas (SiHCl ₃ ) and a boron source gas (B ₂ H ₂ ) are diluted in a carrier gas (hydrogen). The process gas 20 is fed into the reaction chamber 30 at a pressure in the range of 20 PSI to 50 PSI, so that it flows to the upper surface 300a of the wafer 300, and on the front surface 300a of the wafer 300 at a vapor growth temperature of about 1070 ° C An epitaxial layer 301 is formed.

In addition, a purge gas 21 is passed through the second air inlet 37 of the reaction chamber 30 to the hollow channel 330 located in the ejector pin 33. In this embodiment, the purge gas 21 is preferably the same as the carrier gas in the process gas 20. The same is hydrogen. In a preferred solution, the process gas 20 is introduced into the reaction chamber 30 from the first air inlet 35 while the purge gas 21 is introduced from the second air inlet 37.

It can be known from the foregoing description of the vapor phase growth device of this embodiment that the second air inlet 37 and the inlet 331 located on the ejector rod 33 can communicate through a guide pipe (not shown), so that The purge gas is transmitted into the hollow channel 330. Specifically, the hollow channel 330 includes a first hollow channel 332 and a plurality of second hollow channels 333. The first hollow channel 332 extends along the axial direction of the ejector rod 33, and the plurality of second hollow channels 333 and The first hollow channel 332 communicates, and the openings of the plurality of second hollow channels 333 face the side wall of the ejector hole 32 when the ejector 33 is at the lowest position within the lifting range.

In this way, even if the process gas 20 entering from the first air inlet 35 flows below the holder 31, when this part of the process gas 20 flows to the back surface 300b of the wafer 300 through the gap between the ejector hole 32 and the ejector pin 33, Will be pushed from the hollow channel 330 in the bottom 31a of the receiver 31 to the ejector hole The purge gas 21 blown out by 32 is blocked (ie, blown off), so that the process gas 20 does not reach the back surface 300b of the wafer 300, which reduces or avoids the deposition of the back surface 300b of the wafer 300 and destroying the morphology of the epitaxial wafer formed.

In a preferred solution, the arrangement of the first hollow channel 332 and the second hollow channel 333 in the ejector rod 33 is shown in FIG. 3 and FIG. 4. The first hollow channel 332 is located on the axial center line of the ejector rod 33. The two hollow channels 333 are perpendicular to the axial direction of the ejector rod 33 and open to the ejector hole 32.

In order to better make the purge gas 21 achieve the purpose of blocking the process gas 20, the purge gas 21 entering from the second air inlet 37 is preferably maintained at a specific pressure, so as to make the purge gas 21 reach a plurality of first The two hollow channels 333 and the ejector holes 32 satisfy the function of blocking the process gas 20 under the receiver 31 from reaching the back surface 300 b of the wafer 300.

In this embodiment, the purge gas 21 introduced from the second air inlet 37 is approximately a pressure value in a range of 20 PSI to 50 PSI. This is because, when the pressure of the purge gas 21 from the second air inlet 37 into the hollow channel 330 inside the bottom 31a of the susceptor 31 is too small, the purge gas 21 cannot effectively flow into each ejector hole 32, It cannot effectively block the process gas 20 under the receiver 31; when the pressure is too large, the purge gas 21 has a high purge efficiency, but the purge gas 21 and the process gas 20 in the reaction chamber 30 cannot be properly adjusted. It is released from the exhaust port 36 in such a manner that more purge gas 21 or carrier gas easily reaches the front surface 300a of the wafer 300, which is disadvantageous for the formation of the epitaxial layer 301.

As the process gas 20 flowing on the front surface 300a of the wafer 300 continues to undergo decomposition reactions, an epitaxial layer 301 is formed on the surface 300a of the wafer 300. When the required epitaxial layer 301 is reached, the vapor phase growth process is stopped, and Stop the introduction of the process gas 20 and the purge gas 21. In this embodiment, a predetermined time, such as 10 seconds, elapses after the process gas 20 is stopped from being passed in. Then, the purge gas 21 is stopped to better ensure that the process gas 20 is difficult to reach the back surface 300 b of the wafer 300. In a preferred solution, after the process gas 20 and the purge gas 21 are stopped, the remaining gas in the reaction chamber 30 is discharged from the reaction chamber 30 through the exhaust port 36.

Finally, after cooling, the wafer 300 covered with the epitaxial layer 301 on the front surface 300a is transferred out of the reaction chamber 30 through the transfer device. Specifically, when the wafer 300 on the susceptor 31 is movable (unrestricted or lifted), the reaction chamber 30 is filled with an inert gas to make the pressure inside and outside the reaction chamber 30 equal, and the ejector rod 33 rises to make the wafer 300 is detached from the holder 31, and then the transfer device enters the acquisition wafer 300, and the ejector rod 33 is lowered to the lowest position (that is, the state during vapor growth), and the wafer 300 is transferred to the outside of the reaction chamber 30 by the transfer device, but the present invention is not limited thereto.

The above steps are only a brief description of the process of vapor phase formation of the epitaxial layer 301 on the wafer 300. In the reaction chamber 30 and the vapor phase growth process of the actual vapor growth device, other components and steps may be included in order to achieve For additional features or optimization purposes. For example, the susceptor 31 can move up and down in the reaction chamber 30 and can complete the action of the wafer 300 in the reaction chamber 30 together with the ejector 33 and the transfer device.

In addition, it should be noted that this embodiment focuses on describing a brief process of performing vapor phase growth in the vapor phase growth apparatus, and the actual process also includes transferring the wafer 300 into the reaction chamber 30 before the vapor phase growth, and The stage at which the wafer 300 is transferred out of the reaction chamber 30 after the vapor phase growth is completed. At the corresponding stage, the ejector pin 33 will leave the lowest position and perform the lifting operation, so that the ejector pin 33 is used to support the back surface 300b of the wafer 300. At this time, it is usually not Involving the vapor phase growth process, that is, there is no problem of forming pin spots. Therefore, this embodiment mainly describes the solution that the pin 33 is at the lowest position in the lifting movement during the vapor phase growth. Those skilled in the art can make other changes to the vapor phase growth process and method without departing from the connotation of the present invention, which still belong to The protection scope of the present invention.

This embodiment describes a case where a vapor phase growth apparatus includes only one holder 31 and only one wafer 300 is placed in a vapor phase growth process. Those skilled in the art should understand that the solution of the present invention can be applied to various types of ejector rods. 33 A vapor phase growth apparatus that performs substrate input and output.

In summary, the present invention provides a vapor phase growth device and a vapor phase growth method. The vapor phase growth device has a reaction chamber 30 and a plurality of ejector rods 33. The ejector rods 33 can be raised and lowered along the ejector hole 32 and have a In the lowest position, a hollow channel 330 for introducing the purge gas 21 is formed in the ejector pin 33; the hollow channel 330 includes a first hollow channel 332 and a plurality of second hollow channels 333, wherein the first hollow channel 332 Extending along the axial direction of the ejector rod 33, a plurality of second hollow channels 333 communicate with the first hollow channel 332, and the openings of the plurality of second hollow channels 333 face the ejector rod when the ejector rod 33 is at the lowest position. The side wall of the rod hole 32. During the gas phase growth process, the process gas 20 is introduced into the reaction chamber 30 from the first air inlet 35, and the second air inlet 37 is provided with one or more guide pipes, openings 331, A hollow channel 332 and a second hollow channel 333 pass a purge gas 21 into the ejector hole 32. The purge gas 21 ejected from the ejector hole 32 blocks other gases below the ejector hole 32 such as the process gas 20. effect.

The inventors also investigated the flatness of the epitaxial wafer obtained by using the holder, the vapor growth device, and the vapor growth method provided in this embodiment. Specifically, the epitaxial wafer was measured by a wafer geometry measurement system (KLAWaferSight). The SFQR (Site flatness front least-squares range) value on the front side of the wafer. The results show that the SFQR value of the epitaxial wafer obtained can be reduced below 28nm.

It should be noted that the embodiments in this specification are described in an incremental manner. As for the method disclosed in the embodiment, since it corresponds to the structure disclosed in the embodiment, the description is relatively simple. For the relevant part, refer to the description of the structure part.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the rights of the present invention. Any person skilled in the art can make use of the disclosed methods and technical contents to the present invention without departing from the spirit and scope of the present invention. The technical solution may make possible changes and modifications. Therefore, any simple modification, equivalent change, or modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention belongs to the technical solution of the present invention. protected range.

Claims (13)

A vapor phase growth device includes a holder including a bottom portion and a side portion surrounding the bottom portion. The bottom portion and the side portion define a pit for placing a substrate, and a plurality of holders are formed on the holder. Ejector holes that pass through the bottom; can be raised and lowered along the ejector holes and have a lowermost ejector rod; a hollow channel for introducing purge gas is formed in the ejector rod; and for introducing process gas A first air inlet; and a second air inlet for passing a purge gas, the purge gas flows into the ejector pin hole through the second air inlet and the hollow channel. The vapor phase growth device according to claim 1, wherein the hollow channel includes a first hollow channel and a plurality of second hollow channels, the first hollow channel extending in an axial direction of the ejector rod, and the plurality of hollow channels A second hollow channel is in communication with the first hollow channel, and the openings of the plurality of second hollow channels face the side wall of the ejector hole when the ejector is at the lowest position. The vapor-phase growth device according to claim 2, wherein a plurality of the second hollow channels are uniformly distributed radially with the first hollow channel as a center. The vapor-phase growth apparatus according to claim 2, wherein a plurality of the second hollow channels are distributed on the same horizontal plane. The vapor phase growth device according to claim 2, wherein the second hollow channel is a strip-shaped straight hole or an arc-shaped hole. The vapor phase growth device according to claim 1, wherein the vapor phase growth device further includes an exhaust port for exhausting gas to the outside of the vapor phase growth device. The vapor-phase growth device according to claim 1, wherein the vapor-phase growth device further includes a guide pipe through which the purge gas passes into the hollow channel. A vapor phase growth method using the vapor phase growth device according to any one of claims 1 to 7, comprising: placing a substrate on the receiver; and passing the first gas inlet to the vapor phase growth device. A process gas for forming a predetermined film layer on the substrate is passed in, and a purge gas is introduced into the ejector hole through the second air inlet and the hollow channel. The vapor-phase growth method according to claim 8, wherein the purge gas is passed into the first hollow channel at a pressure ranging from 20 PSI to 50 PSI. The vapor phase growth method according to claim 8, wherein the process gas includes a source gas and a carrier gas. The vapor phase growth method according to claim 10, wherein the purge gas and the carrier gas are the same gas. The vapor-phase growth method according to claim 8, wherein the process gas and the purge gas are passed in simultaneously. The vapor phase growth method according to claim 8, wherein after the process gas is stopped from being passed in, the purge gas is continued in for a predetermined time.