JP5257424B2 - Epitaxial growth equipment - Google Patents

Description

  The present invention relates to an epitaxial growth apparatus for forming an epitaxial film on the surface of a semiconductor wafer, and more particularly to purification of a reaction chamber of the epitaxial growth apparatus.

In the field of semiconductor substrate manufacturing, an epitaxial wafer is known in which an epitaxial film is grown on the surface of a silicon wafer. An epitaxial wafer is obtained by forming an epitaxial film on the surface of a silicon wafer (semiconductor wafer) by epitaxial growth.
In recent years, with the high integration of MOS memory devices, memory malfunction (soft error) due to α particles and latch-up in CMOS IC cannot be ignored. As a solution to these problems, an epitaxial wafer having an epitaxial film capable of eliminating a grow-in defect that hinders device fabrication has attracted attention. Recently, an epitaxial wafer has been actively used in the manufacture of CMOS / IC. Its range of use is expanding further.

A vapor phase growth method is generally used as an epitaxial growth method for a silicon wafer. Silane (SiH ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , SiCl _4, etc.) gases are generally used as the reaction gas (raw material gas), and H ₂ gas or the like is used as the carrier gas.
As one type of epitaxial film deposition apparatus, a single-wafer epitaxial growth apparatus is known. This single-wafer growth apparatus has a compact reaction chamber and employs a radiant heating method using a halogen lamp. Since the single wafer processing is performed, it is easy to design soaking conditions and gas flow distribution, and the characteristics of the epitaxial film can be enhanced. Therefore, it is suitable for processing a large-diameter silicon wafer.

Hereinafter, a conventional single-wafer epitaxial growth apparatus will be described in detail with reference to FIG.
As shown in FIG. 16, the conventional single wafer epitaxial growth apparatus includes a reaction chamber 12 for forming an epitaxial film on the surface of the silicon wafer W, and a transfer means for transferring the silicon wafer W into the reaction chamber 12. A transfer chamber 13 (transfer chamber) and a communication passage 11 that communicates the reaction chamber 12 and the transfer chamber 13 are provided.
The silicon wafer W in the transfer chamber 13 is transferred to the susceptor 18 of the reaction chamber 12 by the transfer means through the communication path 11. Thereafter, a reaction gas is supplied to the reaction chamber 12 to form an epitaxial film on the surface of the silicon wafer W.
At the time of film formation, it is important that no particles adhere to the surface of the silicon wafer W. If an epitaxial film is formed without removing particles, there is a possibility that a mound, a stacking fault, or the like occurs in the epitaxial film. These defects are later discovered as LPD (Light Point Defects).

  Therefore, for example, an epitaxial growth apparatus disclosed in Patent Document 1 has been developed in order to remove particles on the wafer surface. In Patent Document 1, as shown in FIG. 16, a nozzle 14 for supplying purge gas to the communication path 11 is provided above the communication path 11 in order to prevent the reaction gas from flowing from the reaction chamber 12 to the communication path 11. A plurality are arranged. At the time of film formation, a purge gas (hydrogen gas) is blown out from each nozzle 14. Thereby, the phenomenon in which the by-product 50 resulting from the component of the reaction gas is deposited on the upper wall surface of the communication path 11 can be suppressed.

JP 2003-109993 A

By the way, there are many known causes of particle generation. Among them, the by-product 50 deposited on the upper wall surface of the communication path 11 is peeled off, and this may be carried to the surface of the silicon wafer W by convection of the furnace gas in the reaction chamber 12 and detected as particles.
The susceptor 18 is configured to be rotatable by a rotary motor, and the silicon wafer W is rotated at a predetermined rotation speed in the circumferential direction via the susceptor 18 during film formation. An annular preheat ring R is disposed on the outer periphery of the susceptor 18. The preheat ring R is an annular heater that is fixed to the inner peripheral wall of the dome mounting body 25 that defines the reaction chamber 12 and that heats the reaction gas immediately before contacting the wafer surface. Therefore, there is a gap between the rotatable susceptor 18 and the fixed preheat ring R.

As shown in FIG. 16, the communication path 11 in which the by-product 50 is deposited is arranged at a position lower than the susceptor position at the time of film formation. Therefore, during film formation, the preheat ring R and the susceptor 18 serve as a partition plate that divides the reaction chamber 12 in the vertical direction, and the reaction gas hardly flows into the communication path 11.
However, a part of the reaction gas passes through the gap between the susceptor 18 and the preheat ring R and enters the communication path 11 to deposit the by-product 50. In particular, since the portion of the communication path 11 on the reaction chamber 12 side has a high concentration, the deposition amount also increases. In addition, among the portions of the communication passage 11 on the reaction chamber 12 side, a large amount of by-products 50 is likely to be generated, particularly on the reaction gas supply side (windward side). Therefore, the possibility that the by-product 50 after separation is transported to the surface of the silicon wafer W by convection in the reaction chamber 12 is further increased.
The purge gas flows in the communication passage 11 in order to prevent such a by-product 50 from being deposited. However, the present situation is that such an effect is not sufficiently exhibited.

  By the way, in the epitaxial growth apparatus, a reaction gas for forming an epitaxial film on the surface of the silicon wafer W is supplied from a supply port formed in the upper part of the inner peripheral wall of the dome mounting body 25. The reaction gas is allowed to flow horizontally toward the discharge port facing the supply port in the inner peripheral wall of the dome mounting body 25. On the other hand, purge gas is jetted through the nozzles 14 into the communication passage 11 whose length direction is substantially perpendicular to the flow of the reaction gas in the horizontal plane. Normally, the purge gas is generated by a purge gas supply source, and from among the nozzles 14 arranged on the reaction gas discharge port side (reaction gas discharge port side), the reaction gas supply port side (reaction gas supply port side) ) Are sequentially supplied to the reaction chamber 12 through the communication passage 11 toward the nozzle 14 arranged in the above.

  For this reason, the flow rate of the purge gas on the reaction gas supply port side becomes smaller than that on the discharge port side. In addition, the hydrogen replacement efficiency of the purge gas on the reaction gas supply port side is lower than that on the discharge port side. As a result, the reactive gas flows around the nozzle on the reactive gas supply port side, and a reactive gas by-product 50 is easily formed near the nozzle. The attached byproduct 50 is peeled off and adheres to the silicon wafer surface. Thus, when an epitaxial film is formed on the surface of the silicon wafer W, there is a problem that LPD is likely to occur.

  The present invention controls the flow of purge gas flowing through the communication path, suppresses by-products deposited on the upper wall surface of the communication path, and can reduce the generation amount of particles on the semiconductor wafer, thereby reducing the LPD. An object of the present invention is to provide an epitaxial growth apparatus capable of obtaining an epitaxial wafer.

  The invention according to claim 1 includes a reaction chamber in which a semiconductor wafer is accommodated, and a transfer chamber communicated with the reaction chamber via a communication path, and the supply port provided in the reaction chamber In the epitaxial film forming apparatus for forming an epitaxial film on the surface of the semiconductor wafer by flowing a reaction gas toward the discharge port provided in the reaction chamber facing the supply port, the supply port and the discharge port are: The purge gas, which is spaced apart in the width direction of the communication path and is ejected into the communication path, is an epitaxial film forming apparatus in which the flow rate on the supply port side in the communication path is greater than that on the discharge port side.

As the semiconductor wafer, for example, a silicon wafer, a gallium arsenide wafer, or the like can be employed.
As an apparatus for forming the epitaxial film, for example, a single wafer type epitaxial growth apparatus can be adopted.
As the purge gas, for example, hydrogen gas can be employed. Hydrogen gas is ejected from a nozzle on the upper wall of the communication path. The number of nozzles formed is not limited. There may be one or two or more. Further, the flow rate of the ejected hydrogen gas is not limited.
The nozzle has a cylindrical shape with a predetermined length. For example, a cylindrical shape or a rectangular tube shape may be used.

In the epitaxial growth apparatus according to the first aspect, the reaction gas for forming the epitaxial film on the surface of the semiconductor wafer is supplied from the supply port of the reaction chamber. The reaction gas is flowed toward a discharge port disposed opposite to the supply port. On the other hand, the purge gas (hydrogen gas) is jetted into a long communication path in the length direction in a direction substantially perpendicular to the flow of the reaction gas.
At this time, in the communication path, the flow rate of the purge gas on the supply port side is made larger than that on the discharge port side. This improves the efficiency of hydrogen replacement between the reaction gas and the purge gas in the vicinity of the nozzle on the reaction gas supply port side. As a result, by-products are less likely to adhere near the nozzle on the supply port side.
Further, the purge gas on the discharge port side easily flows to the discharge port together with the reaction gas even if the flow rate is smaller than that on the supply port side. Therefore, the wraparound of the reaction gas is suppressed even in the vicinity of the nozzle on the discharge port side, and the by-product becomes difficult to adhere. As a result, LPD on the surface of the semiconductor wafer after epitaxial film formation is reduced.

  According to a second aspect of the present invention, there is provided an injection path formed on the upper wall of the communication path, the length of which extends in the width direction of the communication path and injecting purge gas into the communication path, and the injection path and the communication path. The purge gas is injected into the injection path from the reaction gas supply port side, and has a plurality of openings of the same diameter that communicate with the passage and are arranged in the length direction of the injection path. The epitaxial film forming apparatus described.

  In the epitaxial growth apparatus of the second aspect, an injection path that is long in the width direction of the communication path into which the purge gas is injected is provided on the upper wall of the communication path. A plurality of openings of the same diameter arranged in the length direction of the injection path are disposed on the upper wall of the communication path. Then, the purge gas is sequentially injected from the reaction gas supply port side of the injection path. Thereby, the purge gas flow rate on the reaction gas supply port side can be made larger than that on the reaction gas discharge port side. That is, the hydrogen replacement efficiency between the reaction gas and the purge gas is improved also on the reaction gas supply port side, and the by-product is less likely to adhere to the vicinity of the nozzle.

  The invention according to claim 3 is formed in the upper wall of the communication path, and is formed in the upper wall with an injection path for directing a length direction in the width direction of the communication path and injecting purge gas into the communication path. The injection path communicates with the communication path, and has a plurality of openings of the same diameter aligned in the length direction of the injection path, and a part of the opening on the reaction gas discharge side is closed. An epitaxial film forming apparatus according to claim 1.

  In the epitaxial growth apparatus according to the third aspect, the injection path and a plurality of openings having the same diameter are disposed on the upper wall of the communication path. Moreover, a part of the opening on the outlet side is closed. Therefore, when the purge gas is injected into the injection path from the reaction gas discharge port side, the purge gas sequentially passes through the nozzles arranged on the discharge port side, and is supplied to the communication path. At this time, since some of the nozzles on the discharge port side are closed as described above, the purge gas supply amount on the reaction gas discharge port side is suppressed in the communication path, and the purge gas is introduced to the reaction gas supply port side. It becomes easy. As a result, by-products near the nozzle on the reaction gas supply port side are removed.

  The invention according to claim 4 is formed in the upper wall of the communication path, and is formed in the upper wall with an injection path for injecting purge gas into the communication path with a length direction in the width direction of the communication path. A plurality of openings arranged in the length direction of the injection path, the opening area of the opening on the reaction gas supply side is the reaction gas outlet side The epitaxial film-forming apparatus according to claim 1, which is larger than that.

  In the epitaxial growth apparatus according to the fourth aspect, the injection path and the plurality of openings are disposed on the upper wall of the communication path. Moreover, the opening area of the opening on the reaction gas supply port side is larger than that on the reaction gas discharge port side. Therefore, the purge gas injected into the injection path from the reaction gas discharge port side passes through the nozzles in order from the nozzles arranged on the discharge port side, and is supplied to the communication path. At this time, since the opening area of the opening on the reaction gas supply port side is larger than that on the reaction gas discharge port side as described above, the supply amount of the purge gas on the reaction gas discharge port side is suppressed, and the reaction gas supply Purge gas is easily introduced into the mouth side. Then, by-products near the nozzle on the reaction gas supply port side are removed.

According to the present invention, in the communication path, the purge gas flowing in a direction substantially orthogonal to the flow of the reaction gas is set so that the flow rate on the supply port side is larger than that on the discharge side. Thereby, in the vicinity of the nozzle on the reaction gas supply port side, the hydrogen replacement efficiency of the reaction gas and the purge gas is improved, and the by-product is hardly attached.
As a result, an epitaxial wafer with less LPD can be obtained.

It is a longitudinal cross-sectional view which shows the communicating path between the process chamber and transfer chamber of the epitaxial growth apparatus which concerns on the reference example of this invention, and its periphery. It is a top view which shows the slit member which concerns on the reference example of this invention. It is a front view which shows the slit member which concerns on the reference example of this invention. It is a top view which shows the whole structure of the epitaxial growth apparatus which concerns on the reference example of this invention. It is a longitudinal cross-sectional view of the process chamber of the epitaxial growth apparatus concerning the reference example of this invention. It is a top view which shows the slit member provided in the channel | path of the epitaxial growth apparatus which concerns on Example 1 of this invention. It is a top view which shows the other slit member provided in the channel | path of the epitaxial growth apparatus which concerns on Example 1 of this invention. It is a top view which shows the nozzle of another slit member which concerns on Example 1 of this invention. It is a top view which shows the nozzle of another slit member which concerns on Example 1 of this invention. It is a longitudinal cross-sectional view which shows the communicating path between the process chamber and transfer chamber of the epitaxial film-forming apparatus which concern on Example 2 of this invention, and its periphery. It is a perspective view which shows the communicating path between the process chamber and transfer chamber of the epitaxial film-forming apparatus which concern on Example 2 of this invention, and its periphery. It is a longitudinal cross-sectional view which shows the slit member which concerns on Example 2 of this invention. It is a longitudinal cross-sectional view which shows another slit member which concerns on Example 2 of this invention. It is a graph which shows the LPD distribution of 0.12 micrometer or more of the epitaxial film surface formed into a film by the epitaxial growth apparatus concerning Example 1 of this invention. It is a graph which shows 1.0 micrometer or more LPD distribution of the surface of the epitaxial film formed into a film by the epitaxial growth apparatus concerning Example 1 of this invention. It is a graph which shows LPD distribution of 0.12 micrometer or more of the epitaxial film surface formed into a film with the conventional epitaxial growth apparatus. It is a graph which shows 1.0 micrometer or more LPD distribution of the surface of the epitaxial film formed into a film with the conventional epitaxial growth apparatus. It is a longitudinal cross-sectional view which shows the channel | path between the process chamber of a conventional epitaxial growth apparatus, and a transfer chamber, and its periphery.

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

(Reference example)
First, an epitaxial growth apparatus 10 according to a reference example of the present invention will be described with reference to FIGS.
1 to 3, reference numeral 10 denotes an epitaxial growth apparatus according to a reference example of the present invention. The epitaxial growth apparatus 10 includes two process chambers 20 for forming an epitaxial film on the surface of a silicon wafer (semiconductor wafer) W; , A transfer chamber 13 having a transfer means for transferring the silicon wafer W to the process chamber 20, a loader unit 31 for introducing the silicon wafer W into the transfer chamber 13, and an atmosphere in which the silicon wafer W is depressurized in communication with the loader unit 31. And a load lock chamber 33 held by the The load lock chamber 33 communicates with the transfer chamber 13 in which the transfer chamber 13A is formed.

Next, the process chamber 20 will be described in detail with reference to FIG.
The process chamber 20 is formed by connecting an upper dome 21 and a lower dome 22 each made of a transparent material such as quartz by a cylindrical dome mounting body 25. As a result, a substantially circular sealed reaction chamber 12 is formed in the process chamber 20 in plan view. A plurality of halogen lamps (not shown) for heating the inside of the reaction chamber 12 are arranged above and below the reaction chamber 12 at substantially uniform intervals in the circumferential direction. A gas supply port 16 through which gas flows into the reaction chamber 12 is provided at a predetermined position of the dome mounting body 25. Further, a gas discharge port 17 for discharging the gas in the reaction chamber 12 to the outside of the chamber is provided at a position facing the dome mounting body 25 (a position separated from the gas supply port 16 by 180 °).

The reaction chamber 12 is provided with a susceptor 18 on which the silicon wafer W is placed. As the susceptor 18, a carbon substrate whose surface is coated with a SiC film so as to withstand the high temperature in the reaction chamber 12 is employed. A susceptor support member 19 that supports the susceptor 18 is provided on the back side (downward) of the susceptor 18. Further, the susceptor support member 19 has a shaft portion 23 fixed to a lower portion of a shaft center portion of a cylindrical cover (main body). The shaft portion 23 is rotatably provided by a drive mechanism (not shown). As a result, the cylindrical susceptor support member 19 and the susceptor 18 are also provided rotatably at a predetermined speed in a horizontal plane.
On the outer periphery of the susceptor 18, an annular preheating ring R that heats the reaction gas immediately before coming into contact with the wafer surface is disposed. The preheat ring R is fixed to the inner peripheral wall of the dome mounting body 25. Therefore, a gap exists between the rotatable susceptor 18 and the fixed preheat ring R.

Next, the mechanism for ejecting the purge gas will be described in detail with reference to FIGS.
As shown in FIG. 1, a substantially rectangular parallelepiped slit member 19 is provided between the transfer chamber 13 and the process chamber 20. In the slit member 19, a communication path 11 is defined which communicates the transfer chamber 13 </ b> A of the transfer chamber 13 and the reaction chamber 12 of the process chamber 20. On the transfer chamber 13 side of the slit member 19, a slit valve 34 is provided for sealing the inside of the reaction chamber 12 after inserting the silicon wafer W into the reaction chamber 12 of the process chamber 20. The silicon wafer W is transferred from the transfer chamber 13 </ b> A of the transfer chamber 13 to the reaction chamber 12 of the process chamber 20 through the communication path 11.

As shown in FIGS. 2a and 2b, the communication path 11 is a path having a rectangular shape whose horizontal direction is long and whose vertical cross-sectional shape is long horizontally. The width direction of the communication path 11 refers to a laterally long direction in the vertical cross section of the communication path 11. A large number of nozzles (openings) 14 for ejecting purge gas are arranged on the upper wall of the communication passage 11. Each nozzle 14 has a hole shape in which each length direction is directed in the height direction (vertical direction) of the communication path 11. These nozzles 14 may be slit-shaped.
A guide member 15 is provided on the lower surface side of the upper wall of the communication path 11. The guide member 15 is composed of a plate material suspended in the communication passage 11 and is provided below the nozzle 14 and inclined by 45 ° so that the lower side thereof is located on the reaction chamber side.

Next, a method for forming an epitaxial film on the surface of the silicon wafer W using the epitaxial growth apparatus 10 will be described.
A silicon wafer W (single-side polished wafer) having a diameter of 200 mm and a specific resistance of 15 mΩcm is prepared. Then, the silicon wafer W is loaded into the loader unit 31 shown in FIG. Next, the silicon wafer W is transferred from the loader unit 31 to the load lock chamber 33. Then, the silicon wafer W is once depressurized in the load lock chamber 33 and then restored. Then, the silicon wafer W is transferred to the process chamber 20 via the transfer chamber 13. Specifically, the slit valve 34 is opened, and the silicon wafer W is transferred from the transfer chamber 13 </ b> A to the reaction chamber 12 through the communication path 11. Thereafter, the slit valve 34 is closed to seal the reaction chamber 12.

  Next, the silicon wafer W is placed on the susceptor 18 of the reaction chamber 12 with the polishing surface facing upward by a transfer mechanism (not shown) (FIG. 4). Then, the susceptor 18 is raised to the epitaxial film formation position. Next, the shaft portion 23 of the susceptor support member 19 is rotated at a predetermined speed, and the silicon wafer W mounted on the susceptor 18 is rotated.

Subsequently, hydrogen gas is supplied to the reaction chamber 12 and heated by a halogen lamp, whereby hydrogen baking is performed on the silicon wafer W at 1150 ° C. for 20 seconds. Thereafter, a mixed gas obtained by diluting SiHCl _{3 as} a silicon source gas and B ₂ H ₆ as a boron dopant gas with hydrogen gas is supplied from the gas supply port 16 to the reaction chamber 12. The flow rate of the mixed gas is 30 to 100 L / min. At the same time, the gas used for the reaction in the reaction chamber 12 is discharged from the gas discharge port 17.
Then, heat is radiated by a halogen lamp (not shown) disposed above and below the reaction chamber 12 to keep the temperature of the reaction chamber 12 at 1050 to 1170 ° C. At this time, the susceptor 18 holding the silicon wafer W receives the radiant heat uniformly through the susceptor support member 19 by the lower halogen lamp. As a result, a P-type epitaxial film having a thickness of about 6 μm and a specific resistance of 10 Ωcm can be uniformly grown on the surface of the silicon wafer W.

Next, a method for ejecting the purge gas will be described.
As shown in FIG. 1, when a reaction gas is introduced into the reaction chamber, a purge gas (hydrogen gas) is generated by a purge gas supply source (not shown), and then the purge gas is introduced into the reaction chamber 12 through each nozzle 14.
On the upper wall surface of the communication path 11, a guide member 15 made of a plate material is provided in a state of being suspended from the communication path 11. And the guide member 15 is provided in the state which inclined so that the lower side of the guide member 15 may be located in the reaction chamber side under each nozzle 14. FIG. As a result, the purge gas ejected from each nozzle 14 abuts on the inclined guide member 15 and then flows toward the reaction chamber along the upper wall surface of the communication path 11. Further, since the guide member 15 is inclined so that the lower side thereof is positioned on the reaction chamber side, the purge gas can be flowed downward. As a result, the purge gas ejected from the nozzle 14 can be evenly supplied up and down the communication path 11. Therefore, a by-product is hardly formed on the upper wall surface of the communication path 11. Further, LPD generated on the surface of the epitaxial film can be reduced.

Next, Embodiment 1 of the present invention will be described with reference to FIGS.
The epitaxial wafer apparatus of Example 1 is obtained by adding the following changes to the epitaxial wafer apparatus 10 according to the reference example. That is, the flow rate of the purge gas ejected from each nozzle 14 on the reaction gas supply port side is made larger than that on the reaction gas discharge port side (purge gas flow rate).
Specifically, as shown in FIG. 5a, in the epitaxial growth apparatus, a reaction gas is introduced into the process chamber 20 from the A direction and discharged in the B direction.
Between the process chamber 20 and the transfer chamber 13, there is provided a slit member 19 </ b> A for supplying a purge gas to the reaction chamber 12 in a state orthogonal to the reaction gas flow (A → B) in the reaction chamber 12 in the horizontal plane. ing. In the slit member 19 </ b> A, an injection path 27 for sending purge gas is embedded in the upper wall of the communication path 11. A plurality of nozzles (openings) 14 for ejecting purge gas from the injection path 27 to the reaction chamber 12 are disposed inside the upper wall of the communication path 11. The purge gas is generated by a purge gas supply source (not shown) and is injected into the injection chamber 27 from the reaction gas supply port side (C direction).

Further, as shown in FIG. 5b, purge gas is injected from the reaction gas discharge port side (D direction) and supplied to each nozzle 14 via an injection path 27 detoured on the reaction gas supply side of the slit member. The slit member 19B to be used may be used.
Furthermore, each nozzle 14 that ejects the purge gas may be provided as follows. That is, as shown in FIG. 6, a slit member 19 </ b> C in which a hole (or slit) of a part of the nozzles 14 on the reaction gas discharge port side (B side) is closed may be employed.
Furthermore, as shown in FIG. 7, the slit (or the size of the slit) of each nozzle 14 on the reaction gas supply port side (A side) is larger than that on the discharge port side (B side). The member 19D may be adopted.
As a result, the flow rate of the purge gas on the reaction gas supply port side (A side) can be made larger than that on the discharge port side (B side). For example, the flow rate of the purge gas is 25 slm on the reaction gas supply port side (A side) and 5 slm on the reaction gas discharge port side (A side).

  In this manner, the reaction gas is introduced into the reaction chamber 12 and the purge gas is supplied to the silicon wafer W. Then, an epitaxial film is formed on the surface of the silicon wafer W. For example, as shown in FIG. 5a, the purge gas from the purge gas supply source is injected from the reaction gas supply port side (A side) of the injection path 27 provided in the slit member 19A. The purge gas is supplied from the injection path 27 through each nozzle 14 to the communication path 11 in order from the nozzle 14 on the reaction gas supply port side. Thereafter, the purge gas is supplied from the injection path 27 to the reaction chamber 12 through each nozzle 14.

As a result, for the purge gas ejected from each nozzle 14, the flow rate of the purge gas on the reaction gas supply port side (A side) is larger than that on the discharge port side (B side). The result is the same when the slit members 19B to 19D shown in FIGS. 5b, 6 and 7 are used.
Thereby, the flow of the purge gas is improved in the vicinity of the nozzle 14 on the reaction gas supply port side (A side). Further, it is difficult to generate a gas by-product in the vicinity of the nozzle 14 on the reaction gas supply port side (A side).
The purge gas is caused to flow to the gas outlet 17 together with the gas flow of the reaction gas. For this reason, the purge gas on the reaction gas discharge port side (B side) tends to flow to the gas discharge port 17 even if the flow rate is smaller than that on the supply port side (A side). Therefore, there is no wraparound of the reaction gas in the vicinity of the nozzle on the discharge port side (B side), and the by-product is difficult to adhere.
As a result, an epitaxial wafer with less LPD can be obtained.
Other configurations, operations, and effects are substantially the same as those of the reference example, and thus description thereof is omitted.

Next, an epitaxial film forming apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS.
As shown in FIGS. 8 to 10, the epitaxial film forming apparatus of Example 2 has the following three points. That is, (1) The nozzles 14 are arranged so as to be inclined by 30 ° as an example so that the portion on the communication path side is located on the reaction gas supply port side (FIG. 10). (2) In a state in which the transfer chamber side port portion 11a formed on the transfer chamber side of the communication path 11 is inclined by 45 ° below each nozzle 14 so that the lower side is positioned on the reaction chamber side. (FIG. 8). (3) The slit valve (open / close valve) 34 is provided with a flat plate valve body 34a that is inclined so that the lower side is located on the reaction chamber side and closes the transfer chamber side opening 11a ( FIG. 8).

  In the second embodiment, the purge gas ejected from each nozzle 14 to the communication path 11 contacts the valve body 34a of the slit valve 34 that blocks the transfer chamber side opening 11a. At this time, the valve body 34a is inclined so that the lower side is located on the reaction chamber side in accordance with the inclination of the transfer chamber side opening 11a. Therefore, a part of the purge gas guided by the valve body 34 a flows along substantially the entire upper wall surface of the communication path 11. Thereby, it becomes difficult for a by-product to adhere to the upper wall surface of the communication path 11.

Further, here, the nozzles 14 formed on the upper wall of the communication path 11 are inclined so that portions on the communication path side are located on the reaction gas supply port side. Therefore, the purge gas jetted into the communication passage 11 has a larger flow rate of the purge gas on the reaction gas supply port side (the elliptical region E side in FIG. 9) than that on the reaction gas discharge port side. As a result, the hydrogen replacement efficiency between the reaction gas and the purge gas is improved in the vicinity of the reaction gas supply port in the reaction chamber side portion of the communication path 11. Therefore, on the upper wall surface of the communication path 11, it is difficult for the by-product to adhere to the vicinity of the nozzle on the supply port side.
On the other hand, the purge gas on the discharge port side easily flows to the discharge port together with the reaction gas even if the flow rate is smaller than that on the reaction gas supply port side. Therefore, the wraparound of the reaction gas is suppressed even in the vicinity of the nozzle on the discharge port side, and the by-product becomes difficult to adhere. As a result, generation of LPD on the surface of the silicon wafer W can be reduced after epitaxial film formation.
As shown in FIG. 11, such an effect is obtained in the same way even when the inclination angle of each nozzle 14 is gradually increased by 0 to 60 ° toward the reaction gas discharge port side in the communication path 11. be able to.
Other configurations, operations, and effects are substantially the same as those of the reference example, and thus description thereof is omitted.

Next, in the epitaxial growth apparatus 10 of the present invention, an experiment was performed in which an epitaxial film was formed on the surface of the silicon wafer W and LPD generated on the surface of the epitaxial film after film formation was evaluated. The LPD was evaluated using a particle counter. Then, LPDs having a size of 0.12 μm or more and 1.0 μm or more were observed using a map. Graphs showing these results are shown in FIGS. 12 and 13, respectively.
Further, LPD was also evaluated using a conventional epitaxial growth apparatus that supplies a purge gas from the reaction gas outlet side (B side). The confirmation method is the same as above. The results are shown in FIG. 14 and FIG.
As is apparent from FIGS. 14 and 15, it was confirmed that LPD was reduced by using the epitaxial growth apparatus 10 according to the present invention. This indicates that by-products are less likely to adhere to the vicinity of the purge gas nozzle 14.

10 Epitaxial growth equipment,
11 Communication path,
11a Transfer chamber side mouth,
12 reaction chamber,
13A Transfer room,
14 nozzles,
15 guide members,
16 supply port,
17 outlet,
27 Injection path,
34 Slit valve (open / close valve),
34a valve body,
W Silicon wafer (semiconductor wafer).

Claims (4)

A reaction chamber containing a semiconductor wafer;
A transfer chamber communicated with the reaction chamber via a communication path,
Epitaxial film formation for forming an epitaxial film on the surface of a semiconductor wafer by flowing a reaction gas from a supply port provided in the reaction chamber toward a discharge port provided in the reaction chamber facing the supply port In the device
The supply port and the discharge port are spaced apart in the width direction of the communication path,
An epitaxial film forming apparatus in which the purge gas ejected into the communication path has a flow rate on the supply port side in the communication path larger than that on the discharge port side. An injection path that is formed on the upper wall of the communication path, directs the length direction in the width direction of the communication path, and injects purge gas into the communication path;
The injection path and the communication path communicate with each other, and have a plurality of openings with the same diameter arranged in the length direction of the injection path,
The epitaxial film forming apparatus according to claim 1, wherein the purge gas is injected into the injection path from the reaction gas supply port side. An injection path that is formed on the upper wall of the communication path, directs the length direction in the width direction of the communication path, and injects purge gas into the communication path;
Formed in the upper wall, communicating the injection path and the communication path, and having a plurality of openings of the same diameter aligned in the length direction of the injection path,
The epitaxial film-forming apparatus according to claim 1, wherein a part of the opening on the reaction gas outlet side is closed. An injection path that is formed on the upper wall of the communication path, directs the length direction in the width direction of the communication path, and injects purge gas into the communication path;
A plurality of openings formed in the upper wall, communicating the injection path and the communication path, arranged in the length direction of the injection path;
The epitaxial film forming apparatus according to claim 1, wherein an opening area of the opening on the reaction gas supply port side is larger than that on the reaction gas discharge port side.

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