TW201929050A - Epitaxial growth device and method for manufacturing epitaxial wafer using the same - Google Patents

Abstract

Provided is an epitaxial growth device, which is capable of improving the robustness of controlling film thickness uniformity. An epitaxial growth device 100 according to the present invention, includes a susceptor 20, which carries a semiconductor wafer W; a first gas supplier 150, which supplies first process gas G1 to an upper surface of the semiconductor wafer W; a second gas supplier 170, which supplies second process gas G2 to control gas flow of the first process gas G1 in a periphery of the semiconductor wafer W; wherein said epitaxial growth device 100 is characterized in that a main flow path F of gas flow of the second process gas G2 flows unto the susceptor 20 while supplying the first and second process gas G1, G2 at the same time, and the second gas supplier is arranged to separate said main flow path from the periphery of the semiconductor wafer W.

Description

Epitaxial growth device and manufacturing method of semiconductor epitaxial wafer using the same

The present invention relates to an epitaxial growth device and a method for manufacturing a semiconductor epitaxial wafer using the same.

An epitaxial wafer is an epitaxial film grown on the surface of a semiconductor wafer. For example, when completeness of crystallization is required or when a multilayer structure with different resistivity is required, etc., a vapor-grown single-crystal silicon film (epitaxial growth) on a silicon wafer is used to manufacture an epitaxial silicon wafer.

In the production of epitaxial wafers, for example, a single wafer processing (single wafer processing) epitaxial growth device is used. Here, a general epitaxial epitaxial growth device will be described with reference to FIG. 1. As shown in FIG. 1, the epitaxial growth device 900 includes a dense chamber 10 including an upper dome 11, a lower dome 12, and a dome mounting body 13. The dense chamber 10 defines an epitaxial film formation chamber. In addition, the dome-shaped mounting body 13 is drawn with the base as a boundary, and the upper pad 17 and the lower pad 18 are drawn. In the closed chamber 10, a reaction gas supply port 15A and a reaction gas discharge port 16A are provided on the upper gasket 17 side of the side facing position, and supply and discharge of the reaction gas G _P are performed, respectively. And, provided on the side of the atmospheric chamber 10 gas supply port 15B and the gas exhaust outlet to the atmosphere lower liner 18 side position 16B, respectively G _A gas supplying air and discharge to a lower portion remains secret chamber dome 12 In a hydrogen atmosphere.

In the back room 10, a susceptor 20 on which the semiconductor wafer W is mounted is arranged. The base 20 is supported by a base support shaft 30 from below. The base support shaft 30 supports the lower peripheral portion of the base 20 with three support rods (not shown) at the front end of the arm. In addition, three through holes (here, one is not shown) are formed in the base 20, and one through hole is also formed in each arm of the base support shaft 30. The through holes of these arms and the through holes of the base are inserted into LIFT PINs 40A, 40B, and 40C (however, the lifting pins 40B are not shown in the schematic cross-sectional view of FIG. 1 because of their arrangement) . The lower end portion of the lifting jack 40 is supported by a lifting shaft 50. The semiconductor wafer W carried in the closet 10 is supported on the susceptor 20 mounted on the semiconductor wafer W, and the epitaxial wafer grown after the vapor phase epitaxy is taken out of the closet 20, by lifting and lowering the shaft 50, The lifting and lowering lever 40 lifts and lowers the through hole of the arm and the through hole of the base while moving, and lifts and lowers the semiconductor wafer W at its upper end. When the epitaxial layer EP is formed by using this leaf type epitaxial growth device 900, the upper surface of the semiconductor wafer W mounted on the susceptor 20 is brought into contact with the reaction gas G _P while the susceptor 20 is rotated. The reaction gas G _P means a gas in which a source gas is mixed in a carrier gas. When forming a silicon epitaxial layer as the epitaxial layer EP, a silicon source gas such as trichlorosilane gas is used as the source gas. In addition, the side surface of the base 20 is generally interposed therebetween with a gap of about 3 mm, and is covered with a pre-heat ring 60.

The pre-heat ring 60 is also called a pre-heating ring or a pre-heating ring. The reaction gas G _P flows into the epitaxial film formation chamber. Before the reaction gas G _P contacts the semiconductor wafer W, the pre-heat ring 60 preheats the susceptor 20 and the reaction gas. G _P improves the thermal uniformity of the semiconductor wafer W before and during film formation, and improves the uniformity of the epitaxial film.

The flow of the reaction gas G _P and the atmospheric gas G _A on the side of the reaction gas discharge port 16A and the atmospheric gas discharge port 16B will be described with reference to FIG. 2. As shown in FIG. 2, the reaction gas G _P mainly flows to the reaction gas discharge port 16A side, and the atmospheric gas G _A mainly flows to the atmosphere gas discharge port 16B side, and passes through the gap g between the base 20 and the preheating ring 60. A part of the reaction gas G _P can sink into the atmospheric gas discharge port 16B side. Conversely, the atmospheric gas G _A can blow that part onto the gas discharge port 16A side. However, unlike the reaction gas G _P , the atmospheric gas G _A is basically not intended to be supplied toward the upper surface of the semiconductor wafer W.

Here, Patent Document 1 discloses a gas injection device. In an epitaxial growth device, a first group of ejection ports is provided, and an injection of an angle at which a first treatment gas is added to a flat surface at an angle is provided; and an ejection port The second group is close to the first group of the ejection outlets, and supplies a laminar flow of the pressurized second processing gas substantially along the planar surface; the planar surface is vertically enlarged to the second group of the ejection outlets.

According to Patent Document 1, since the two kinds of ejection ports are used, the flow between the processing gases used in forming the epitaxial layer interacts with each other, and it is desired to improve the thickness and unevenness of the epitaxial layer or both.
[Advanced technical documents]
[Patent Document]

[Patent Document 1] Special Table No. 2015-534283

[Problems to be Solved by the Invention]

The inventors expect that the epitaxial growth device 800 shown in FIG. 3 can control the uniformity of the film thickness when the epitaxial layer EP is formed on the semiconductor wafer W, and try an experiment. Here, the epitaxial growth device 800 includes a first gas supply unit 15 including a first discharge port 15A that discharges a first processing gas G1 containing a reaction gas G _P , and supplies a first processing gas to the upper surface of the semiconductor wafer W. G1; and a second gas supply unit 70 including a second discharge port 70A of a second processing gas G2 that emits a first processing gas G1 in a peripheral portion of the semiconductor wafer W and directed toward the upper surface of the semiconductor wafer W A second processing gas G2 is supplied. Then, as shown in FIG. 3, when the semiconductor wafer W is viewed in plan, the supply direction of the first processing gas G1 and the second processing gas G2 intersect perpendicularly.

When the epitaxial growth device 800 is used, the first processing gas G1 flows uniformly into the peripheral portion of the wafer, and it is expected that the film thickness uniformity of the epitaxial layer EP can be improved. However, when the epitaxial layer EP is actually formed, as shown in FIG. 7B described later in detail, it is confirmed that bumps (roll-up and roll-down) may occur in a peripheral portion of a wafer called a “bump”. In order to determine that the film thickness of the epitaxial peripheral portion (wafer edge portion) changes monotonically or monotonically, such bump formation cannot be allowed.

Moreover, it was confirmed that such bump formation is also greatly affected by the number of rotations of the susceptor 20 and the supply ratio of the first processing gas G1 in the central portion and the peripheral portion of the wafer. Therefore, the inventors understand that when using the second processing gas G2, it is necessary to improve the robustness of controlling the uniformity of the film thickness during the formation of the epitaxial layer as a new subject.

Therefore, the present invention provides an epitaxial growth device that can improve the robustness of the film thickness uniformity control during the formation of the epitaxial layer. It is another object of the present invention to provide a method for manufacturing a semiconductor epitaxial wafer using the epitaxial growth device.
[Means to solve the problem]

The inventors intensively studied in order to solve the above-mentioned problems. During epitaxial growth, by rotating the susceptor 20, the semiconductor wafer W mounted thereon is also rotated, and the first processing gas G1 is sprayed onto the upper surface of the semiconductor wafer W. Therefore, as the susceptor 20 and the semiconductor wafer W rotate, the gas flow of the first processing gas G1 and the second processing gas G2 also changes, which is considered to be one of the main causes of interference. After further discussion, as shown in the mode of FIG. 3, in the rotation direction on the base 20, between the second processing gas G2 and the reaction gas discharge port 16A, an area where the concentration of the first processing gas G1 became locally high was found. This can be a cause of the formation of the bumps.

Therefore, when the second processing gas G2 is used, in order to uniformize the concentration distribution on the upper surface of the semiconductor wafer W, the inventors conceived to control the gas flow of the first processing gas G1 by appropriately adjusting the direction of the gas flow of the second processing gas G2. Then, the present inventors have found that by using an epitaxial growth apparatus that optimizes the flow direction of the second processing gas G2, the above-mentioned problems can be solved and the present invention has been completed.

That is, the gist structure of the present invention is the same as the following.
(1) An epitaxial growth device, which epitaxially grows an epitaxial layer on the surface of a semiconductor wafer.
It is characterized by:
Secret room
A pedestal for mounting the semiconductor wafer inside the dense chamber;
The first gas supply unit includes a first discharge port, discharges a first processing gas containing a reaction gas for vapor phase epitaxial growth of the epitaxial layer, and supplies the first processing gas to an upper surface of the semiconductor wafer;
The second gas supply unit includes a second discharge port, and discharges a second processing gas that controls the flow of the first processing gas in the peripheral portion of the semiconductor wafer, and supplies the second processing to the upper surface direction of the semiconductor wafer. gas;
When the first and second processing gases are supplied simultaneously, the main flow path of the gas flow of the second processing gas flows into the pedestal, and the second gas supply section is installed to isolate the main flow path from the periphery of the semiconductor wafer. .

(2) The epitaxial growth device described in (1) above, which has a discharge port for discharging the first processing gas at a position opposite to the first gas discharge port;
In the rotation direction of the base, the second gas discharge port is arranged to flow upward in the rotation direction between the first gas discharge port and the discharge port.

(3) The epitaxial growth device according to the above (2), wherein the second gas discharge port is arranged on an upstream side of the first processing gas in a rotation direction of the susceptor.

(4) The epitaxial growth device according to the above (2) or (3), wherein the second treatment is performed in a first direction from the first gas discharge port to the discharge port, and the second process is discharged from the second gas discharge port. The angle formed by the gas release direction is an acute angle.

(5) The epitaxial growth device according to the above (4), wherein an angle formed by the first direction and the releasing direction is in a range from 40 degrees to 80 degrees.

(6) The epitaxial growth device according to any one of (1) to (5), wherein the first processing gas includes a source gas and a carrier gas, and the second processing gas is formed of the carrier gas.

(7) The epitaxial growth device according to any one of (1) to (6), wherein the shortest distance between the periphery of the semiconductor wafer and the main flow path of the second processing gas is 5 mm (mm) or more Below 40mm.

(8) A method for manufacturing a semiconductor epitaxial wafer, comprising the step of loading a semiconductor wafer on the pedestal of the epitaxial growth apparatus described in any one of (1) to (7) above; (1) A step in which a process gas and the second process gas are epitaxially grown on the surface of the semiconductor wafer to form an epitaxial layer.
[Inventive effect]

According to the present invention, there is provided an epitaxial growth device capable of improving the uniformity of film thickness control during the formation of an epitaxial layer. Furthermore, according to the present invention, a method for manufacturing a semiconductor epitaxial wafer using the epitaxial growth device can be provided.

Hereinafter, an epitaxial growth device 100 according to the present invention will be described with reference to the drawings. In addition, the aspect ratios of the respective components in the figure are exaggerated for convenience of explanation, and are different from the actual ones. In order to simplify the description, an appropriate block diagram is used for each configuration. In addition, referring to FIG. 1, the same reference numerals are used for the structures overlapping with the general epitaxial growth device 900 described above.

(Epimorph growth device)
An epitaxial growth device 100 according to an embodiment of the present invention is a vapor phase epitaxial growth epitaxial layer EP on the surface of a semiconductor wafer W, and can be used to manufacture an epitaxial growth device for a semiconductor epitaxial wafer EW. The epitaxial growth device 100 will be described with reference to FIGS. 1 and 4.

The epitaxial growth apparatus 100 according to the present embodiment includes a dense chamber 10, a susceptor 20 on which a semiconductor wafer W is mounted, and a first gas supply unit 150 that supplies a first processing gas G1 to the upper surface of the semiconductor wafer. And a second gas supply unit 170 that supplies the second processing gas G2 toward the upper surface of the semiconductor wafer W. Here, the first gas supply unit 150 includes a first gas discharge port 150A, and discharges a first process gas G1 containing a reaction gas for vapor phase epitaxial growth epitaxial layer EP. The second gas supply unit 170 includes a second gas discharge port 170A, and discharges a second processing gas G2 that controls the flow of the first processing gas G1 in the peripheral portion of the semiconductor wafer W. In addition, in FIG. 4, a discharge port 160 through which the first process gas G1 is discharged is shown at a position opposite to the first gas discharge port 150A.

For convenience of description, the direction from the discharge port 160 toward the first gas supply unit 150 is defined as the x-axis, which is orthogonal to the y-axis, and the direction on the second gas supply unit 170 side is defined as the y-axis. In addition, the thickness direction of the semiconductor wafer W is the z direction (the side in which the epitaxial layer EP is formed is the positive direction of the z axis). The center position of the semiconductor wafer W is defined as the origin of the x, y, and z spaces. The angle formed by the y-axis and the center position of the second gas discharge port 170A is defined as θ ₁ . In addition, the angle formed by the first direction (that is, the negative direction of the x-axis) from the first gas discharge port 150A toward the discharge port 160 and the discharge direction of the second process gas G2 from the second gas discharge port 170A is defined as an angle θ ₂ .

Then, the first processing gas G1 includes a reaction gas, and the epitaxial layer EP is formed on the surface of the semiconductor wafer W by the reaction gas. Therefore, the first processing gas G1 is supplied to the upper surface of the semiconductor wafer W. In the present specification, a reaction gas means a gas in which a source gas is mixed with a carrier gas. On the other hand, since the second processing gas G2 controls the flow of the first processing gas G1, it is not necessary to directly contact the upper surface of the semiconductor wafer W, and the second processing gas G2 is supplied. By supplying the second processing gas G2 toward the upper surface of the semiconductor wafer W, the second processing gas G2 controls the flow of the first processing gas G1.

Here, in the epitaxial growth device 100 according to this embodiment, the main flow path F of the second process gas G2 gas flow when the first and second process gases G1 and G2 are supplied simultaneously flows into the base 20, and the second The gas supply unit 170 isolates the main flow path F from the periphery W _{0 of the} semiconductor wafer W.

The main flow path F regarding the flow of the second process gas G2 will be described with reference to FIGS. 4 and 5A and 5B. FIG. 5A schematically illustrates the main flow path F of the second processing gas when the first processing gas G1 and the second processing gas G2 flow while rotating the susceptor 20 according to the epitaxial growth device 100 according to this embodiment. The main flow path F of the flow of the second processing gas G2 is a flow direction in which the diffusion speed of the second processing gas is maximized. FIG. 5B shows an example of the mass concentration distribution of the source gas (specifically, trichlorosilane) when the first processing gas G1 and the second processing gas G2 flow simultaneously in the configuration of FIG. 5A. The thick portion in FIG. 5B indicates a region where the mass concentration of the source gas is relatively low (therefore, the mass concentration of the second processing gas G2 is relatively high), and the light portion indicates that the mass concentration of the source gas is relatively high (therefore, the second processing gas G2 mass concentration is relatively low). The flow direction where the diffusion velocity becomes the maximum corresponds to the main flow path F shown in Figs. 4 and 5A.

Since the main flow path F of the second processing gas G2 is isolated from the periphery W _{0 of the} semiconductor wafer W, the mass concentration of the first processing gas G1 in the peripheral portion of the semiconductor wafer W can be uniformly diffused. Therefore, it is possible to suppress the formation of the bumps when the epitaxial layer EP is formed, and also to improve the robustness of the uniformity control of the film thickness during the formation of the epitaxial layer due to the main cause of interference such as the rotation number of the pedestal.

In addition, in order to isolate the main flow path F of the second processing gas G2 from the periphery W _{0 of the} semiconductor wafer W, as long as the position and direction of the second gas discharge port 170A that discharges the second processing gas G2 are appropriately adjusted (the nozzle can also be said ). In addition, whether or not the main flow path F is isolated from the periphery W _{0 of the} semiconductor wafer W can be determined by, for example, numerical analysis using a finite volume method. In such numerical analysis, for example, a commercially available general-purpose thermal fluid analysis software is used to set at least the flow rate of the first processing gas G1, the release start point and the release direction, the flow rate of the second treatment gas G2, the release start point and the release direction, and the rotation of the base 20. The direction and the number of rotations, the chamber space, and the surface temperature of the wafer are used as parameters, as long as the diffusion of the first processing gas G1 or the second processing gas G2 is dynamically analyzed.

In order to obtain the effect of the present invention more reliably, as shown in FIG. 4, in the rotation direction of the base 20, it is preferable to arrange the second gas discharge port 170A to flow in the rotation direction between the first gas discharge port 150A and the discharge port 160 ( That is, -90 degrees <θ ₁ <90 degrees). For this purpose, it is preferable to arrange the second gas discharge port 170A on the upstream side of the first processing gas G1 in the rotation direction of the susceptor 20 (that is, in the x-axis direction, 0 degrees <θ ₁ <90 degrees) to form 2 degrees <θ ₁ <15 degrees is more desirable. A suitable example of θ ₁ is a range of 8 to 12 degrees. At this time, it is preferable to arrange the second gas discharge port 170A to be shifted from the center of the semiconductor wafer W (that is, the center of the dense chamber 10) to the upstream side (x-axis direction) of the first processing gas G1 by a predetermined distance L, as this predetermined The distance L and the radius R to the semiconductor wafer W may be about 1/10 to 1/3. Therefore, the direction of the second gas discharge port 170A may be adjusted appropriately by the distance L in which the position of the second gas discharge port 170A is shifted toward the upstream side of the first processing gas G1. Specifically, when the radius of the conductor wafer is, for example, 150 mm (diameter 300 mm), the position of the second gas discharge port 170A may be shifted from about 15 mm to 50 mm toward the upstream side of the first processing gas G1. In addition, as for the distance staggered in the y direction, if it is arranged on the circumference of the dense room, as long as the distance L staggered in the x direction is determined, it can be determined corresponding to the distance L.

In order to obtain the above-mentioned main flow path F, the angle θ ₂ formed by the first direction from the first gas discharge port 150A to the discharge port 160 and the discharge direction of the second process gas discharge from the second gas discharge port 170A is an acute angle. It is more reliable. In particular, if the angle θ ₂ formed by the first direction and the releasing direction is within a range of 40 ° to 80 °, it is more accurate, and if it is within a range of 45 ° to 55 °, it is more accurate. For this purpose, the larger the above-mentioned θ ₁ or the larger the distance L is, the more reliable the angle θ ₂ becomes.

In order to ensure the effect of the present invention, the shortest distance l ₀ between the periphery W _{0 of} the semiconductor wafer W and the main flow path F of the second processing gas G1 is more than 0 mm and 40 mm, and more preferably 5 mm or more. When the shortest distance _{10 is} within this range, the gas flow in the peripheral portion of the semiconductor wafer of the first processing gas G1 can be reliably controlled, and the concentration distribution of the source gas can be rationalized. The shortest distance l ₀ between the surrounding W ₀ and the main flow path F means the shortest distance between two different curves.

In addition, the installation position of the second gas discharge port 170A is just a suitable form. The main flow path F of the second processing gas G2 flow flows into the susceptor 20 as long as the main flow path F and the periphery W _{0 of the} semiconductor wafer W. Isolation does not limit the installation position of the second gas discharge port 170A. In addition, the relationship between the installation position of the second gas release port 170A and the base may be provided by installing the installation position of the second gas release port 170A so that the main flow path F of the air flow flows into the base. The horizontal position of the seat may be equal to or higher than the base, and it may flow into the base, and the opposite does not matter.

In the epitaxial growth device according to this embodiment, a silicon wafer is preferably used as the semiconductor wafer W, and the epitaxial layer formed on the silicon wafer is preferably a silicon epitaxial layer. However, the epitaxial growth device according to this embodiment can also be applied to compound semiconductor wafers and the like, and can also be applied to heteroepitaxial growth.

Here, the first processing gas G1 includes a source gas and a carrier gas as a reaction gas, and in this case, the second processing gas G2 is preferably formed of a carrier gas. Taking a case where a silicon epitaxial layer is formed in a silicon wafer as an example, a silicon source such as dichlorosilane or trichlorosilane can be used as a source gas, and hydrogen can be used as a carrier gas. When the second processing gas is the same as the carrier gas of the first processing gas, it is desirable not to affect the reaction during epitaxial growth. However, the use of the first and second processing gases G1 and G2 in this embodiment is not limited to these, and may be appropriately selected according to the substrates and epitaxial layer materials of the semiconductor wafer W. Either or both of the first processing gas G1 and the second processing gas G2 may include a dopant gas. If a silicon epitaxial layer is formed in a silicon wafer, a compound gas containing boron, phosphorus, and arsenic can be used.

In order to obtain the main flow path F described above, the ratio of the gas flow rate of the first processing gas G1 to the gas flow rate of the second processing gas G2 is preferably set within a range of 8: 1 to 13: 1. In addition, when the air flow rate includes a plurality of different gases, the air flow rate in the total measurement is referred to. That is, when the first processing gas G1 includes a source gas and hydrogen, it is only necessary to calculate the above ratio using these total gas flow rates.

Hereinafter, although specific embodiments of each configuration of the epitaxial growth device applicable to this embodiment will be described, the present invention is not limited to these specific embodiments.

＜ Secret Room ＞
As shown in FIG. 1, the secret chamber 10 includes an upper dome 11, a lower dome 12, and a dome mounting body 13, and the secret chamber 10 is an epitaxial film formation chamber. In the closed chamber 10, a reaction gas supply port 15A and a reaction gas discharge port 16A are generally provided at positions facing the side surface on the upper pad 17 side, and the reaction gas G _P is supplied and discharged. Further, the chamber 10 is generally provided atmospheric gas supply port 15B, and the atmosphere in the gas discharge port 18 side of the lower liner side surface intersecting the position 16B, the atmospheric gas G _A supplied and discharged. In order to simplify FIG. 1, the supply port and discharge port of the same cross-section as illustrated in the reaction gas and the atmospheric gas G _P G _A, as in FIG. 1, it may set the supply port of the reaction gas and the atmospheric gas G _P G _A parallel. The dome mount 13 has a circular shape similar to the base and the wafer, and has a second nozzle. The dome mounting body 13 has an diameter of about 420 to 470 mm in an epitaxial device for processing a 30 mm wafer.

<Pedestal>
The susceptor 20 is a disc-shaped member on which the semiconductor wafer W is mounted inside the dense chamber 10. The base 20 generally has three through holes that penetrate the front and back surfaces at a regular interval of 120 degrees in the circumferential direction and pass through the front and back surfaces in the vertical direction. These through holes are respectively inserted into LIFT PINs 40A, 40B, and 40C. The base 20 has a thickness of about 2 to 8 mm, and carbon graphite (black lead) can be used as a base material, and the surface thereof is coated with silicon carbide (SiC: Vickers (Vickers hardness) 2, 346 kgf / mm ² ). A counter sinking portion (not shown) is formed on the surface of the susceptor 20 to house the semiconductor wafer W thereon.

＜ Base support shaft ＞
The pedestal support shaft 30 supports the pedestal 20 from below in the back room 10, and its pillars are arranged substantially coaxially with the center of the pedestal 20.

＜ Elevator jacks ＞
LIFT PINs 40A, 40B, and 40C are respectively inserted into the through holes of the base 20. The lifting pins 40A, 40B, and 40C can be lifted up and down by the lifting shaft 50 to support the semiconductor wafer W (the area of the back portion with a radius of 50% or more) at the upper end of the lifting pin and the base 20 The semiconductor wafer W is loaded and unloaded. The operation of raising and lowering the ejector lever will be described later. The materials of the lifting rods 40A, 40B, and 40C are the same as those of the base 20, and black lead and / or silicon carbide are generally used.

<Lifting shaft>
The elevating shaft 50 is divided into hollows of the main pillars accommodating the support shaft 30 of the base, and the lower ends of the elevating rods are supported at the front ends of the pillars, respectively. The lifting shaft 50 is preferably made of quartz. The lifting shaft can be moved up and down along the main column of the base support shaft 30 to lift the lifting rods 40A, 40B, and 40C.

＜ Preheating ring ＞
The preheating ring 60 covers the side of the base 20 with a gap therebetween. Irradiating light to heat a halogen lamp (not shown), flow into the reaction gas G _P epitaxial film forming chamber before the gas G _P with the semiconductor wafer W contact reaction, the reaction preheated gas preheat ring 60 G _P. The preheating ring 60 also preheats the base 20 at the same time. In this manner, the preheating ring 60 improves the thermal uniformity of the susceptor 20 and the semiconductor wafer W before and during film formation. The preheating ring 60 is also the same as the base 20, and black lead can be used as a base material, and the surface is coated with silicon carbide (SiC: Vickers (Vickers hardness) 2, 346 kgf / mm ² ).

＜ Heating lamp ＞
The heating lamp is arranged in the upper region and the lower region of the secret chamber 10, and generally, a halogen lamp or an infrared lamp which has a rapid temperature rise and excellent temperature controllability is used.

Moreover, it is preferable to use hydrogen as the atmospheric gas introduced into the dense chamber. Instead of supplying atmospheric gas to the upper surface of the semiconductor wafer W, it is the same as described above.

(Manufacturing method of semiconductor epitaxial wafer)
In addition, a method for manufacturing a semiconductor epitaxial wafer according to an embodiment of the present invention includes a step of loading a semiconductor wafer on the pedestal of the epitaxial growth device, and supplying the first processing gas and the second processing simultaneously. A step of vapor-epitaxially growing an epitaxial layer on the surface of the semiconductor wafer by gas. According to this manufacturing method, it is possible to improve the robustness of controlling the uniformity of the film thickness during the formation of the epitaxial layer.

The growth conditions when an epitaxial layer is formed on the surface of the semiconductor wafer W may be general. If a silicon epitaxial layer is formed in a silicon wafer, for example, hydrogen is used as a carrier gas, and a source gas such as dichlorosilane or trichlorosilane is introduced into the epitaxial growth furnace as the first treatment gas. The source gas has a different growth temperature, and can be epitaxially grown on a semiconductor wafer by a CVD method in a temperature range of about 1000 to 1200 ° C. As for the second processing gas, hydrogen is preferably used in the same manner as described above. The thickness of the epitaxial layer EP layer may be in a range of 1 to 15 μm.
[Example]

Next, in order to clarify the effects of the present invention, the following examples are given, but the present invention is not limited to the following examples.

(Example 1)
Using the epitaxial growth device shown in FIG. 4, the main flow path F of the second processing gas G2 and the film thickness distribution of the formed epitaxial layer when the silicon epitaxial layer is formed on the surface of the silicon wafer are numerically analyzed. The supply port 170A of the second processing gas G2 is provided at a position on the upstream side L: 40 mm, the angle θ ₁ is 10 degrees, and the angle θ ₂ is 50 degrees.

In the first embodiment, trichlorosilane (TCS) and hydrogen were introduced as the first processing gas G1, and hydrogen was introduced as the second processing gas G2. The total flow rate of the first process gas G1 is 84 slm (H ₂ : 75 slm, TCS: 9 slm), and the total flow rate of the second process gas G2 is 7 slm. The number of rotations of the pedestal was 70 rpm, and the wafer temperature on the pedestal was 1130 ° C.

In the numerical analysis of the mass concentration distribution of the first process gas, the mass concentration distribution of the TCS is calculated, and as parameters, the flow rate of the first process gas G1, the release starting position and the release direction, the flow rate of the second process gas G2, and the release start position are set. And the release direction, the rotation direction and number of rotations of the susceptor 20, the chamber space, the wafer surface temperature, and the furnace pressure (normal pressure). Then, the main flow path F is obtained from the obtained mass concentration distribution. In addition, the numerical analysis of the epitaxial growth process uses TCS as the silicon source to obtain the epitaxial growth rate distribution.

FIG. 6A illustrates a main flow path F based on a numerical analysis result. As shown in FIG. 6A, the main flow path F is usually isolated from the periphery W _{0 of the} silicon wafer. In the above numerical analysis, the shortest distance ₁₀ is 25 mm. The calculation result of the film thickness distribution in the wafer peripheral portion of the epitaxial layer obtained at this time is shown in FIG. 7A. From FIG. 7A, it can be confirmed that only the epitaxial film is rolled up.

(Comparative example 1)
The structure of FIG. 3 is the same as that of Example 1 so that the moving distance of the upstream side of the first processing gas G1 is 0 (zero) so that the direction of the supply port 170A of the second processing gas G2 faces the wafer center. , Numerical analysis of the film thickness distribution of the main flow path F and the epitaxial layer formed.

The results of Comparative Example 1 are the same as those of Example 1, and are shown in Figs. 6B and 7B. From FIG. 6B, in Comparative Example 1, it can be confirmed that the main flow path F flows into the semiconductor wafer W. Then, according to FIG. 7B, it can be confirmed that the epitaxial layer in the peripheral portion of the wafer called the bump is raised (after being rolled up, rolled down).

In Example 1 and Comparative Example 1, the condition 1 is set to 70 rpm of the base rotation number and the distribution ratio of the first processing gas is 5: 1 (condition 1). Even at 32 rpm of the base rotation number, the first processing gas distribution is set. In the case of a ratio of 1: 1 (condition 2), numerical analysis was also performed. In conditions 1 and 2, respectively, the epitaxial layer film thickness difference between the positions of 140 mm and 148 mm in the radial direction when the flow rate of the second processing gas is 3 slm, 5 slm, and 7 slm is shown in FIG. Figure 8B (Comparative Example 1).

According to FIGS. 8A and 8B, in Comparative Example 1, as the hydrogen flow rate of the second processing gas increases, the responsiveness of the peripheral film thickness of the epitaxial wafer does not increase monotonously, and it is confirmed that the influence of noise is large. In contrast, in Example 1, as the hydrogen flow rate of the second processing gas increased, it was confirmed that the responsiveness of the peripheral film thickness of the epitaxial wafer increased monotonously, and the noise effect was small, and it was confirmed that the robustness can be improved.
[Industrial availability]

According to the present invention, it is possible to provide an epitaxial growth device capable of improving the uniformity control of the film thickness during the formation of the epitaxial layer.

10‧‧‧ secret room;

11‧‧‧ upper dome;

12‧‧‧ lower dome;

13‧‧‧ dome mounting body;

15A‧‧‧reaction gas supply port;

15B‧‧‧ Atmospheric gas supply port;

16A‧‧‧Reaction gas discharge port;

16B‧‧‧ Atmospheric gas outlet;

17‧‧‧ upper pad;

18‧‧‧ lower cushion;

20‧‧‧ base;

30‧‧‧ base support shaft;

40‧‧‧ lifting jack;

40A, 40B, 40C ‧‧‧Lift PIN;

50‧‧‧ lift shaft;

60‧‧‧preheating ring;

70A‧‧‧ second release;

100‧‧‧ epitaxial growth device;

150‧‧‧ the first gas supply department;

150A‧‧‧ the first gas outlet;

160‧‧‧ discharge

170‧‧‧second gas supply department;

170A‧‧‧second gas outlet;

800‧‧‧Epimorph growth device;

900‧‧‧ epitaxial growth device;

EP‧‧‧ epitaxial layer;

EW‧‧‧ semiconductor epitaxial wafer;

F‧‧‧ mainstream road;

G _A ‧‧‧ Atmospheric gas;

G _P ‧‧‧reactive gas;

W‧‧‧ semiconductor wafer;

W ₀ ‧‧‧ the periphery of the semiconductor wafer W;

G1‧‧‧ the first processing gas;

G2‧‧‧ the second processing gas;

G _A ‧‧‧ Atmospheric gas;

G _P ‧‧‧Reactive gas.

[FIG. 1] A schematic sectional view of an epitaxial growth device according to a conventional technique;

[FIG. 2] A schematic cross-sectional view illustrating the air flow near the gas discharge port of the epitaxial growth device;

[FIG. 3] A schematic plan view of an epitaxial growth device including a second processing gas that the present inventors discussed;

4 is a schematic plan view of an epitaxial growth device according to an embodiment of the present invention;

[FIG. 5A] A schematic diagram showing the main flow path F of the second processing gas;

[FIG. 5B] An example of the mass concentration distribution of the source gas controlled by the second process gas;

[FIG. 6A] A diagram showing a mass concentration distribution of the first processing gas in Example 1;

[FIG. 6B] A mass concentration distribution chart of the first processing gas in Comparative Example 1;

[FIG. 7A] A diagram showing a film thickness distribution in a peripheral portion of the epitaxial layer formed in Example 1;

[FIG. 7B] A diagram showing a film thickness distribution in a peripheral portion of the epitaxial layer formed in Comparative Example 1;

[FIG. 8A] A diagram showing a relationship between the air flow rate of the second processing gas and the film thickness difference in the peripheral portion of the wafer when the growth conditions are changed; and

8B is a graph showing the relationship between the gas flow rate of the second processing gas in Comparative Example 1 and the film thickness difference in the peripheral portion of the wafer when the growth conditions are changed.

Claims (11)

An epitaxial growth device, which epitaxially grows an epitaxial layer on the surface of a semiconductor wafer. It is characterized by: Secret room A pedestal for mounting the semiconductor wafer inside the dense chamber; The first gas supply unit includes a first discharge port, discharges a first processing gas containing a reaction gas for vapor phase epitaxial growth of the epitaxial layer, and supplies the first processing gas to an upper surface of the semiconductor wafer; The second gas supply unit includes a second discharge port, and discharges a second processing gas that controls the flow of the first processing gas in the peripheral portion of the semiconductor wafer, and supplies the second process to the upper surface of the semiconductor wafer. gas; When the first and second processing gases are supplied simultaneously, the main flow path of the gas flow of the second processing gas flows into the pedestal, and the second gas supply section is installed to isolate the main flow path from the periphery of the semiconductor wafer. . The epitaxial growth device according to item 1 of the scope of the patent application, wherein the epitaxial growth device has a discharge port for discharging the first processing gas at a position opposite to the first gas discharge port; In the rotation direction of the base, the second gas discharge port is arranged to flow upward in the rotation direction between the first gas discharge port and the discharge port. The epitaxial growth device according to item 2 of the scope of patent application, wherein the second gas discharge port is arranged on the upstream side of the first processing gas in the rotation direction of the susceptor. The epitaxial growth device according to item 2 of the patent application scope, wherein the first direction from the first gas discharge port to the discharge port and the discharge direction of the second process gas from the second gas discharge port The angle formed is an acute angle. The epitaxial growth device according to item 3 of the scope of patent application, wherein the first direction from the first gas discharge port to the discharge port and the discharge direction of the second process gas from the second gas discharge port The angle formed is an acute angle. The epitaxial growth device according to item 4 of the scope of patent application, wherein an angle formed by the first direction and the releasing direction is in a range from 40 degrees to 80 degrees. The epitaxial growth device according to item 5 of the scope of patent application, wherein an angle formed by the first direction and the releasing direction is in a range from 40 degrees to 80 degrees. The epitaxial growth device according to any one of claims 1 to 7, wherein the first processing gas includes a source gas and a carrier gas, The second processing gas is formed of the carrier gas. The epitaxial growth device according to any one of claims 1 to 7, wherein the shortest distance between the periphery of the semiconductor wafer and the main flow path of the second processing gas is 5 mm (mm) or more. Below 40mm. In the epitaxial growth device according to item 8 of the scope of patent application, the shortest distance between the periphery of the semiconductor wafer and the main flow path of the second processing gas is 5 mm (mm) or more and 40 mm or less. A method for manufacturing a semiconductor epitaxial wafer includes: A step of loading a semiconductor wafer on the above-mentioned pedestal of the epitaxial growth device according to any one of claims 1 to 10; and And a step of supplying the first processing gas and the second processing gas at the same time to epitaxially grow an epitaxial layer on the surface of the semiconductor wafer.