CN102939406B - Film forming apparatus - Google Patents

Abstract

Disclosed is a film formation device equipped with a raw material gas discharge unit which has a structure that can be manufactured more readily than those of conventional film formation devices and can discharge multiple raw material gases onto a substrate while cooling the raw material gases without causing the contamination of the raw material gases with each other. The raw material gas discharge unit (20) comprises: a hollow discharge vessel (21) which has multiple discharge holes (22) formed on the wall thereof; and multiple pipes (31a1 to 31a3, 31b1 to 31b3) which are arranged in a hollow part of the discharge vessel (21), and each of which has a through hole (32a1 to 32a3, 32b1 to 32b3) on the outer periphery side surface thereof, wherein the outer periphery part of each of the through-holes (32a1 to 32a3, 32b1 to 32b3) formed on the outer periphery side surface of the pipes is in closely contact with the inner surface of the wall of the vessel, and the through-holes (32a1 to 32a3, 32b1 to 32b3) are communicated with the discharge hole (22). When a cooling medium is circulated in the hollow part of the discharge vessel (21), raw material gases that pass through the pipes (31a1 to 31a3, 31b1 to 31b3) can be cooled.

Description

Film forming device

technical field

The invention relates to a film forming device, in particular to the technical field of CVD. the

Background technique

Currently, gallium nitride (GaN) is used as a material for electronic components such as light emitting diodes. In order to produce a gallium nitride crystal, a film forming apparatus using a metal organic vapor phase growth (MOCVD) method is used. the

FIG. 8 shows an internal configuration diagram of a conventional film formation apparatus 110 used in the MOCVD method. the

The film forming apparatus 110 has a vacuum chamber 112 , a substrate holding table 141 holding a substrate 140 , a first pipe 132 a through which a first source gas passes, and a second pipe 132 b through which a second source gas passes. the

The vacuum evacuation device 113 is connected to the vacuum chamber 112, and the inside of the vacuum chamber 112 is configured to be evacuated. the

The first piping 132 a and the second piping 132 b are arranged in the vacuum chamber 112 , and the first discharge hole 122 a and the second discharge hole 122 b provided at one end face the substrate 140 on the substrate holding table 141 , respectively. The other ends of the first pipe 132a and the second pipe 132b respectively airtightly penetrate the wall surface of the vacuum chamber 112 and extend to the outside of the vacuum chamber 112, and are connected to the first gas supply part 135a for releasing the first raw material gas and the second The second gas supply unit 135b from which the raw material gas is released. the

An electric heater 142 is attached to the substrate holding table 141 , and a power supply unit 144 is electrically connected to the electric heater 142 . When a DC voltage is applied from the power supply device 144 to the electric heater 142 , the electric heater 142 generates heat to heat the substrate 140 held on the surface of the substrate holding table 141 . the

A rotating shaft 146 is attached to the rear surface of the substrate holding table 141 so as to be perpendicular to the rear surface, and a rotating device 147 is connected to the rotating shaft 146 to rotate the rotating shaft 146 around the central axis of the rotating shaft 146 . When the rotating device 147 rotates the rotating shaft 146 , the substrate holding table 141 rotates together with the substrate 140 parallel to the surface of the substrate 140 . the

A method of forming a GaN thin film on the surface of the substrate 140 using the film forming apparatus 110 will be described. the

The inside of the vacuum chamber 112 is evacuated, and then the vacuum evacuation is continued. The substrate 140 is placed on the substrate holding table 141 , and the substrate 140 is rotated parallel to the surface of the substrate 140 . the

If the substrate 140 is heated while ammonia (NH ₃ ) as the first source gas and trimethylgallium (TMGa, (CH ₃ ) ₃ Ga) as the second source gas are released from the first discharge hole 122a and the second discharge hole 122a, respectively. Hole 122b discharges toward the surface of substrate 140 and mixes, then

(CH ₃ ) ₃ Ga+NH ₃ →GaN+3CH ₄

The chemical reaction makes the GaN film formed on the surface of the substrate 140 . CH ₄ generated together with GaN is evacuated to the outside of the vacuum chamber 112 by the evacuation device 113 .

If the first raw material gas and the second raw material gas are mixed, a reaction will occur. Therefore, in order to prevent the first raw material gas and the second raw material gas from reacting until they reach the substrate 140, the first discharge hole 122a of the first pipe 132a and the second raw material gas must be connected to each other. The second discharge hole 122b of the second pipe 132b is close to a distance of 10 to 40 mm from the surface of the substrate 140 , so that the first source gas and the second source gas are mixed in front of the surface of the substrate 140 . Furthermore, in order to uniformly form a film on the surface of the substrate 140, the first discharge holes 122a and the second discharge holes 122b must be alternately arranged in rows and columns on the plane opposite to the substrate 140, and the first source gas must be supplied in a uniform ratio. and the second source gas are emitted to the surface of the substrate 140 . the

In addition, during film formation, the substrate 140 is heated to a high temperature of 1100° C. However, if the first piping 132 a and the second piping 132 b are close to the substrate 140, the first piping 132 a and the second piping 132 b are heated, and the raw material gas may flow in the first piping. The interior of the pipe 132a and the second pipe 132b is disassembled. Therefore, a cooling device for cooling the first pipe 132a and the second pipe 132b is required. the

In order to satisfy the above conditions, the structure of the raw material gas discharge part of the film forming apparatus must be complex, such as having a layered structure and forming tens of thousands of discharge holes with thin tubes, which poses a problem of difficulty in fabrication. the

Patent Documents

Patent Document 1: Japanese Patent Application Laid-Open No. 8-91989.

Contents of the invention

The problem to be solved by the invention

The present invention was conceived in order to solve the above-mentioned disadvantages of the prior art, and its object is to provide a film forming apparatus having a raw material gas discharge unit, which can be manufactured more easily by using the conventional method. With this structure, a plurality of raw material gases can be cooled and released onto the substrate without mixing at the same time.

solutions to problems

In order to solve the above-mentioned problems, the present invention provides a film forming apparatus including a vacuum chamber, a hollow discharge container provided in the vacuum chamber and provided with a plurality of discharge holes, and a plurality of tubular discharge containers disposed in the hollow portion of the discharge container. An introduction part, a gas supply part for supplying a raw material gas to each of the introduction parts, and a substrate holding part for holding a substrate at a position opposite to the discharge hole of the discharge container, and the outer peripheral side of each of the introduction parts is in close contact with the discharge container. A wall surface facing the hollow portion is provided with a through-hole for communicating the internal space of the introduction portion with the discharge hole at the portion of each of the introduction portions where the contact is made.

The present invention is a film forming apparatus, wherein each of the introduction portions faces the wall surface of the discharge container in parallel to each other and is arranged at equal intervals on the wall surface of the discharge container. the

The present invention is a film forming apparatus, wherein the gas supply unit has a first gas supply unit for releasing a first source gas and a second gas supply unit for releasing a second source gas, and at least one of the introduction units The introduction part is connected to the first gas supply part, and the other introduction part is connected to the second gas supply part. the

The present invention is a film forming apparatus, wherein the introduction part connected to the first gas supply part and the introduction part connected to the second gas supply part are alternately arranged in parallel on the wall surface of the discharge container. the

The present invention is a film forming apparatus including a plurality of auxiliary pipes and a plurality of connecting pipes, the plurality of auxiliary pipes are arranged in the hollow portion of the discharge container, and a plurality of auxiliary through-holes are provided on the outer peripheral side, and the outer peripheral side of the outer peripheral side The outer peripheral portion of the auxiliary through hole is separated from the wall surface of the discharge container, and one end of the plurality of connecting pipes is connected to the auxiliary through hole and the other end is connected to the discharge hole so that the auxiliary through hole and the discharge hole communicate. The gas supply unit has a first gas supply unit for releasing the first source gas and a second gas supply unit for releasing the second source gas, the pipe is connected to the first gas supply unit, and the sub-pipe is connected to the second gas supply unit. supply department. the

The present invention is a film forming apparatus, which is configured such that an introduction port and a discharge port are provided on the container wall of the discharge container, and a refrigerant whose temperature is to be controlled is introduced into the hollow part of the discharge container from the introduction port, and is discharged from the discharge port. Drain the above refrigerant. the

Invention effect

When the refrigerant enters the hollow portion of the discharge container and the introduction part is immersed in the refrigerant, the cooling effect of the raw material gas flowing inside the introduction part can be enhanced to prevent thermal decomposition.

Compared with the conventional manufacturing method of brazing tens of thousands of thin tubes that emit the raw material gas, the raw material gas releasing part can be manufactured in a simple way. the

Description of drawings

FIG. 1 is an internal configuration diagram of a film forming apparatus of the present invention. the

Fig. 2 is a cross-sectional view taken along line A-A of the film forming apparatus of the present invention. the

3( a ) to 3( d ) are schematic diagrams for explaining a method of manufacturing a source gas discharge unit. the

4(a) to 4(f) are schematic diagrams for explaining how to fix the piping and the base plate. the

Fig. 5 is an internal configuration diagram of a second example of a raw material gas discharge unit. the

Fig. 6 is a cross-sectional view taken along line B-B of a second example of a source gas discharge unit. the

7( a ) and 7 ( b ) are schematic diagrams for explaining a source gas discharge unit having a sub-pipe. the

FIG. 8 is an internal configuration diagram of a conventional film forming apparatus. the

Detailed ways

The structure of the film forming apparatus of the present invention will be described. FIG. 1 shows an internal configuration diagram of a film forming apparatus 10, and FIG. 2 shows a cross-sectional view taken along line A-A of the same figure. the

The film forming apparatus 10 has a vacuum chamber 12 , a substrate holding table (substrate holding unit) 41 that holds a substrate 40 , and a source gas discharge unit 20 that discharges a source gas from a discharge port 22 . the

On the groove wall of the vacuum chamber 12, an exhaust port 12a is provided, and a vacuum exhaust device 13 is connected to the exhaust port 12a. The evacuation device 13 is configured to be able to evacuate the inside of the vacuum chamber 12 . the

The substrate holding table 41 is arranged in the vacuum chamber 12 and is configured to be able to hold the substrate 40 on the surface facing the outlet 22 . the

An electric heater 42 is attached to the substrate holding table 41 , and a power supply unit 44 is electrically connected to the electric heater 42 . When a DC voltage is applied from the power supply unit 44 to the electric heater 42 , the electric heater 42 generates heat to heat the substrate 40 held on the substrate holding table 41 . the

One end of the rotating shaft 46 is attached vertically to the back surface of the substrate holding table 41 . The other end of the rotating shaft 46 airtightly passes through the tank wall of the vacuum tank 12 to extend to the outside of the vacuum tank 12 and is connected to the rotating device 47 . The rotation device 47 has a motor here, and is configured to be able to rotate the rotation shaft 46 around the central axis of the rotation shaft 46 . the

When the rotating device 47 rotates the rotating shaft 46, the substrate holding table 41 and the substrate 40 held on the substrate holding table 41 rotate parallel to the back surface of the substrate holding table 41, that is, rotate parallel to the surface of the substrate 40, in other words , rotates around a rotation axis perpendicular to the surface of the substrate 40 . the

The configuration of a first example of the raw material gas discharge unit 20 will be described. the

The raw material gas discharge unit 20 has a hollow discharge container 21 provided with a plurality of discharge holes 22 and a plurality of tubular introduction portions 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ arranged in the hollow portion 25 of the discharge container 21 .

The outer peripheral sides of the introduction portions 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ are in close contact with the wall surface of the discharge container 21 facing the hollow portion 25, and the outer peripheral sides of the introduction portions 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ are in close contact with each other. The above wall portions are provided with through holes 32a ₁ to 32a ₃ , 32b ₁ to 32b ₃ for communicating the internal spaces of the introduction portions 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ and the discharge hole 22 .

The respective introduction portions 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ of the raw material gas discharge portion 20 are pipes provided with through-holes 32a ₁ to 32a ₃ , 32b ₁ to 32b ₃ on the outer peripheral side surfaces.

3( a ) to 3( d ) are schematic diagrams for explaining a method of manufacturing the source gas discharge unit 20 . Each of the pipes (introduction parts) 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ has the same structure, and the pipe (introduction part) represented by reference numeral 31a ₁ will be described.

The discharge container 21 has a flat bottom plate 21a. the

Referring to FIG. 3( a ), pipes 31 a ₁ with one end sealed are arranged parallel to each other at equal intervals on the surface of the bottom plate 21 a. Here, a plurality of parallel depressions are formed at equal intervals on the surface of the bottom plate 21a in advance, and the pipes 31a ₁ are respectively arranged along the respective depressions. However, the present invention is not limited thereto, and the surface of the flat bottom plate 21a may not The piping 31a ₁ is arranged by forming a depression.

Referring to Fig. 3 (b), after the molten solder 29 flows between the surface of the base plate 21a and the outer peripheral side of the piping 31a ₁ , the solder 29 is cooled and solidified, and the surface of the base plate 21a and the piping are connected by so-called brazing process. The outer peripheral side of _31a1 is fixed.

Referring to Fig. 3 (c), a hole is formed by laser processing or mechanical processing, and the hole is formed from the back side of the part of the surface of the bottom plate 21a that is in close contact with the outer peripheral side of the piping 31a ₁ due to brazing processing and the bottom of the bottom plate 21a. The back surface vertically and continuously penetrates the wall surface of the bottom plate 21a and the pipe _31a1 .

Among the formed holes, the part formed in the bottom plate 21a is the discharge hole 22, and the part formed in the piping _31a1 is the through hole _32a1 . If the part of the solder 29 is also regarded as a part of the pipe _31a1 , the outer peripheral (surrounding) part of the through-hole _32a1 in the outer peripheral side of the pipe _31a1 is in close contact with the surface of the bottom plate 21a.

The positional relationship of the holes of the pipes 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ will be described. With reference to FIG. , along each of the pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ , holes are formed at equal intervals to continuously penetrate the wall surface of the discharge container 21 and the side walls of the pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ . Here, "arranged in rows and columns" means that the first straight lines L ₁ ~ L ₄ that are parallel to each other and equally spaced and the second straight lines M that are parallel to each other and equally spaced and cross the first straight lines L ₁ ~ L ₄ are arranged. Each intersection of ₁ ~ M ₅ .

The fixing method of the piping 31a ₁ and the bottom plate _21a is not limited to the above-mentioned method (the first method). As shown in FIG _. 21a forms the discharge holes 22 at the same interval as the center intervals of the through holes _32a1 , and aligns the piping _{31a1 and the bottom plate 21a so that the respective through holes 32a1 and} different discharge holes 22 face (communicate). Then, as shown in FIG. As shown in FIG. 4(b), the outer peripheral side surface of the pipe _31a1 and the surface of the bottom plate 21a are fixed by brazing (second method).

However, in the second method, if the number of discharge holes 22 increases, it will be difficult to align. In addition, since the melted solder 29 may be exposed to the inside of the discharge holes 22 during the soldering process and block the discharge holes 22, The first method is simpler and preferable. the

In the case of the second method, as shown in FIG. 4( c), the through- _holes 32a1 may be formed in advance on the outer peripheral side of the pipe _31a1 so that the outer periphery of one through-hole _32a1 surrounds the outside of the plurality of discharge holes 22. The size is aligned in such a way that a plurality of discharge holes 22 are located inside one through hole 32a ₁ (one through hole 32a ₁ communicates with a plurality of discharge holes 22), and then, as shown in FIG. One through-hole _32a1 communicates with the plurality of discharge holes ₂₂ on the outer peripheral side surface of the bottom plate 21a and the surface of the bottom plate 21a, respectively.

In this case, even if the number of discharge holes 22 is increased, alignment is easy. In addition, since the outer peripheral side surface of the pipe 31a ₁ and the surface of the bottom plate 21a are brazed at a position away from the outer periphery of the discharge hole 22, the solder 29 is exposed. The possibility of reaching the inside of the release hole 22 is reduced.

In addition, _in the case of the second _method , as shown in FIG. The inner side of one discharge hole 22 (one discharge hole 22 communicates with a plurality of through holes _32a1 ) is aligned, and then, as _shown in FIG. Instead, one discharge hole 22 communicates with a plurality of through holes _32a1 .

Next, referring to FIG. 3( d ), the cover portion 21b in a convex shape (cylindrical shape with _one end covered) is arranged on the surface of the bottom plate 21a so as to cover the piping 31a1, and the cover portion 21b is The edge is closely adhered to and fixed to the outer periphery of the bottom plate 21a, and one end, which is the opening end of the pipe _31a1 , passes through the wall surface of the cover part 21b in an airtight manner and is exposed to the outside of the cover part 21b.

The hollow discharge container 21 is comprised by the bottom plate 21a and the cover part 21b. the

The configuration of a second example of the raw material gas discharge unit 20 will be described. the

FIG. 5 shows an internal configuration diagram of a second example of the raw material gas discharge unit 20 , and FIG. 6 shows a cross-sectional view taken along line BB in the same figure. Among the configurations of the second example of the raw material gas discharge unit 20 , the same parts as those of the first example are assigned the same reference numerals and description thereof will be omitted. The second example of the raw material gas discharge part 20 has _{the introduction part of the code|symbol 33a1-33a3, 33b1-33b3 instead of the introduction part} of the code|symbol _31a1-31a3 , _31b1-31b3 .

The outer peripheral side surfaces of each of the introduction portions 33a ₁ to 33a ₃ and 33b ₁ to 33b ₃ are in close contact with the wall surface of the discharge container 21 facing the hollow portion 25, and each of the introduction portions 33a ₁ to 33a ₃ and 33b ₁ to 33b ₃ are in close contact with each other. The portion of the wall surface is provided with through holes 39a ₁ to 39a ₃ , 39b ₁ to 39b ₃ for communicating the internal spaces of the introduction portions 33a ₁ to 33a ₃ , 33b ₁ to 33b ₃ and the discharge hole 22 .

The introduction portions 33a ₁ to 33a ₃ and 33b ₁ to 33b ₃ of the raw material gas discharge unit 20 are grooves, and the openings of the grooves are through holes 39a ₁ to 39a ₃ , 39b ₁ to 39b ₃ .

The method of manufacturing the raw material gas discharge part 20 will be described. Here, openings (through holes) 39a ₁ to 39a ₃ , 39b ₁ to _39b of the grooves (introduction parts) 33a ₁ to 33a ₃ , 33b ₁ to 33b 3 with one end closed _3. In the direction facing the surface of the bottom plate 21a, the edges of the grooves 33a ₁ to 33a ₃ and 33b ₁ to 33b ₃ are brought into close contact with the surface of the bottom plate 21a and fixed by brazing. Next, the discharge hole 22 is formed from the back surface of the bottom plate 21a by laser processing or machining, and the internal spaces of the grooves 33a ₁ to 33a ₃ , 33b ₁ to 33b ₃ communicate with the discharge hole 22 . Next, the cover 21b is arranged to cover the side surfaces of the grooves 33a ₁ to 33a ₃ , 33b ₁ to 33b ₃ , and the edge of the cover 21b is brought into close contact with and fixed to the outer periphery of the bottom plate 21a so that the grooves 33a ₁ to 33a ₃ , 33b The opening ends of ₁ to 33b ₃ airtightly pass through the wall surface of the cover part 21b and are exposed to the outside of the cover part 21b to form a hollow discharge container 21 .

In the structure of the first example, if the radius of one of the pipes 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ is enlarged, the inner diameter area of the pipe cannot be enlarged beyond a predetermined value because it contacts another adjacent pipe. On the other hand, in the structure of the second example, by increasing the depth of the grooves 33a ₁ to 33a ₃ , 33b ₁ to 33b ₃ , the inner diameter area of the grooves can be enlarged, and the amount of the raw material gas passing through the grooves can be reduced. The advantage of increased conductivity.

Referring to FIGS. 1 and 5 , the discharge container 21 of the raw material gas discharge unit 20 is arranged in the vacuum chamber 12 at a position where the wall surface provided with the discharge hole 22 can be parallel to the surface of the substrate 40 held on the substrate holding table 41. . the

2 and 6, one end of the first external pipes 38a ₁ to 38a ₃ is airtightly connected to a plurality of introduction parts (pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ or grooves 33a ₁ to 33a ₃ , 33b ₁ ~ 33b ₃ ) at least one of the opening end of the introduction part (here, the pipes of symbols 31a ₁ ~ 31a ₃ or the grooves of symbols 33a ₁ ~ 33a ₃ ), and one end of the second external piping 38b ₁ ~ 38b ₃ is airtight Connect to the open end of another introduction part (pipes of symbols 31b ₁ to 31b ₃ or grooves of symbols 33b ₁ to 33b ₃ ).

The other ends of the first external pipes 38a ₁ to 38a ₃ and the second external pipes 38b ₁ to 38b ₃ respectively airtightly pass through the wall surface of the vacuum chamber 12 to extend to the outside of the vacuum chamber 12, and are connected to the outlet for releasing the first raw material gas. The first gas supply part 35a and the second gas supply part 35b for releasing the second source gas. Here, the second source gas is a gas that reacts when mixed with the first source gas.

Here, the introduction part connected to the first gas supply part 35a (the pipes of symbols _31a1 to _31a3 or the tanks of symbols _33a1 to _33a3 ) and the introduction part connected to the second gas supply part 35b (symbols _31b1 to _31b3 pipes or _33b1 ~ _33b3 tanks) are alternately arranged in parallel on the wall surface of the discharge container 21 facing the hollow part 25, and the first raw material gas and the second raw material gas released from the different discharge holes 22 are uniform. ratio mix.

The source gas discharge unit 20 with the structure of the first example is not limited to the case where one pipe 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ and one external pipe 38a ₁ to 38a ₃ , 38b ₁ to 38b ₃ are separable. The invention also includes the case where one pipe 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ and one external pipe 38a ₁ to 38a ₃ , 38b ₁ to 38b ₃ are formed from one continuous pipe.

Referring to FIGS. 1 and 5 , an introduction port 23 a and a discharge port 23 b are provided on the wall surface of the discharge container 21 . The first refrigerant pipe 52a and the second refrigerant pipe 52b are respectively connected to the inlet port 23a and the outlet port 23b. The outer refrigerant circulation device 51. the

The refrigerant circulation device 51 introduces the refrigerant whose temperature is controlled into the hollow part 25 of the discharge container 21 from the inlet 23a, and makes each introduction part (pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ or tanks 33a ₁ to 33a ₃ , 33b ₁ ~33b ₃ ) is in contact with the refrigerant, and each introduction part is immersed in the refrigerant, and then the refrigerant is discharged from the discharge port 23b, that is, the refrigerant is circulated in the hollow part 25 of the discharge container 21.

As shown in FIGS. 7( a ) and ( b ), the raw material gas discharge unit 20 of the present invention may have a plurality of sub-pipes 36b ₁ to 36b ₃ arranged in the hollow portion 25 of the discharge container 21 . A plurality of sub through holes 37b ₁ to 37b ₃ are provided on the outer peripheral side of each of the sub pipes 36b ₁ to 36b ₃ , and the outer peripheral portions of the sub through holes 37b ₁ to 37b ₃ on the outer peripheral side are separated from the surface of the bottom plate 21a.

The manufacturing method of the raw material gas discharge part 20 will be described. One end of the plurality of connecting pipes ₃₄₁ to ₃₄₃ is vertically fixed to the surface of the bottom plate 21a by brazing, and the ends of the auxiliary pipes _36b1 to _36b3 are fixed by brazing. The outer peripheral side is fixed to the other end of the connection pipes 34 ₁ to 34 ₃ , and then, laser processing or machining is used to form the bottom plate 21 a and the sub-pipe 36 b ₁ from the back side of the bottom plate 21 a through the inside of the connection pipes 34 ₁ to 34 ₃ . The holes through which the walls of ~36b ₃ penetrate (that is, the release hole 22 and the sub-through holes 37b ₁ ~37b ₃ ). The outer peripheral parts of the auxiliary through holes 37b ₁ to 37b ₃ on the outer peripheral sides of the auxiliary pipes 36b ₁ to 36b ₃ are separated from the wall surface of the discharge container 21, and the auxiliary through holes 37b ₁ to 37b ₃ and the discharge hole 22 are connected through the connecting pipes 34 ₁ to 34 ₃ And connected. In addition, the introduction part (the pipes 31a ₁ to 31a ₃ or the grooves 33a ₁ to 33a ₃ ) is processed by the same method as in the above description.

When the liquid refrigerant is circulated in the hollow portion 25 of the discharge container 21 by the refrigerant circulation device 51, the height of the water surface of the refrigerant is maintained at a height higher than that of the sub-pipes 36b ₁ to 36b ₃ and the introduction portion (pipes 31a ₁ to 31a ₃ or the height of the grooves 33a ₁ to 33a ₃ ), whichever is higher, the sub-pipes 36b ₁ to 36b ₃ and the introduction part are immersed in the refrigerant and circulated simultaneously.

Compared with the introduction part (pipes 31a ₁ to 31a ₃ or grooves 33a ₁ to 33a ₃ ), the sub-pipes 36b ₁ to 36b ₃ have a larger contact area with the refrigerant, and the sub-pipes 36b ₁ to 36b ₃ are separated from the base plate 40 And positioning, and thus easy to cool. Therefore, when the second source gas is more easily decomposed by heat than the first source gas, if the first source gas flows into the introduction part and the second source gas flows through the sub-pipes 36b ₁ to 36b ₃ , it is possible to It is preferable to prevent thermal decomposition of the second raw material gas. For example, when organic metal gas and NH ₃ gas are used as source gases, NH ₃ gas may flow in the introduction part and organic metal gas may flow in sub-pipes 36b ₁ to 36b ₃ .

A method of forming a GaN thin film on the surface of the substrate 40 using the film forming apparatus 10 of the present invention will be described. the

Here, the structure of the first example having the pipes 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ is used in the raw material gas discharge unit 20, however, even when using the pipes 33a ₁ to 33a ₃ and 33b ₁ to 33b ₃ In the case of the raw material gas discharge unit 20 having the structure of the second example and the raw material gas discharge unit 20 having the structure of the sub-pipes 36b ₁ to 36b ₃ , the method of use is the same.

Referring to Fig. 1 and Fig. 2, vacuum exhaust is carried out in the vacuum chamber 12. Subsequently, vacuum evacuation is continued and the vacuum atmosphere in the vacuum chamber 12 is maintained. the

The substrate 40 is carried into the vacuum chamber 12 by a transfer robot not shown in the figure, and the substrate 40 is placed on the substrate holding table 41 . the

The substrate holding table 41 is rotated together with the substrate 40 parallel to the surface of the substrate 40 (ie, centered on a rotation axis perpendicular to the surface of the substrate 40 ), and then the rotation of the substrate 40 is continued. A refrigerant of controlled temperature is introduced into the hollow portion 25 of the discharge container 21, and the pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ are immersed in the refrigerant to be cooled, and then the refrigerant is circulated in the hollow portion 25 to continue cooling.

The electric heater 42 generates heat to heat the substrate 40 . the

In the second gas supply part 35b, the liquid TMGa is bubbled by _H2 gas or _N2 gas, the TMGa gas as the second source gas is released, and the _NH3 gas as the first source gas is released from the first gas The supply part 35a is released. The first source gas passes through the pipes marked 31a ₁ to 31a ₃ , and the second source gas passes through the pipes marked 31b ₁ to 31b ₃ , and is released toward the surface of the substrate 40 from the different discharge holes 22 of the discharge container 21 .

The released first source gas and second source gas are mixed on the surface of the substrate 40 to form a GaN thin film on the surface of the substrate. Byproducts generated together with GaN are evacuated to the outside of the vacuum chamber 12 through the evacuation port 12 a. the

A plurality of discharge holes 22 are spaced apart from each other at equal intervals on the wall surface of the discharge container 21 and arranged in a row, so that the first raw material gas and the second raw material gas discharged from the respective discharge holes 22 are mixed in a uniform ratio on the substrate 40, and A uniform thin film is formed on the surface of the substrate 40 . the

The refrigerant circulates through the hollow portion 25 of the release container 21, and the outer peripheral sides of the pipes 31a ₁ to 31a ₃ and 31b ₁ to 31b ₃ come into contact with the refrigerant to be cooled. Therefore, even if the pipes 31a ₁ to 31a ₃ , 31b ₁ to 31b ₃ are heated by the heat generated by the substrate 40, the temperature does not rise, preventing the flow of the first source gas and the second source gas in the pipes 31a ₁ to 31a ₃ , 31b ₁ . Internal thermal decomposition of ~31b ₃ .

After forming a thin film with a predetermined thickness on the surface of the substrate 40, the supply of the first source gas from the first gas supply unit 35a and the second source gas from the second gas supply unit 35b are stopped, and the formation of the GaN thin film is terminated. . the

After the thin film is formed, the rotation of the substrate 40 by the rotating device 47 is stopped, the heating of the substrate 40 by the electric heater 42 is stopped, and the transfer robot not shown in the figure carries out the substrate 40 to the outside of the vacuum chamber 12, and is delivered to the next vacuum tank 12. process. the

Next, another substrate 40 is carried into the vacuum chamber 12 of the film forming apparatus 10 by a transfer robot not shown in the figure, and film formation is repeated in the above-mentioned method. the

In the above description, the second gas supply unit 35b bubbles liquid TMGa with _H2 gas or _N2 gas to release TMGa gas as the second source gas. Gallium (TEGa), trimethylaluminum (TMAl), trimethylindium (TMIn), silane (SiH ₄ ) and magnesocene (CP ₂ Mg) are bubbled in different reaction vessels, and each reaction is opened and closed The valve of the container is used to release one organometallic gas or a mixed gas of two or more organometallic gases as the second raw material gas.

In this case, after the substrate 40 of sapphire, SiC, Si, or GaN is carried into the vacuum chamber 12, an LT-GaN layer, a GaN layer, and a Si-doped n-type GaN layer can be sequentially stacked on the substrate 40 in the same vacuum chamber 12. layer, a GaN/InGaN multilayer film layer, and a Mg-doped p-type AlGaN layer, that is, a stacked structure that can produce a light-emitting diode element. the

Symbol Description

10: Film forming device

12: Vacuum tank

21: Release container

22: release hole

25: hollow part

23a: Import port

23b: discharge port

31a ₁ ~ 31a ₃ , 31b ₁ ~ 31b ₃ : Introductory part (piping)

32a ₁ to 32a ₃ , 32b ₁ to 32b ₃ : Through holes

33a ₁ ~ 33a ₃ , 33b ₁ ~ 33b ₃ : Introduction part (groove)

35a: 1st gas supply part

35b: Second gas supply part

36b ₁ ~36b ₃ : Auxiliary piping

37b ₁ ~37b ₃ : Auxiliary through holes

39a ₁ to 39a ₃ , 39b ₁ to 39b ₃ : Through holes (openings)

41: Substrate holding part (substrate holding table)

Claims (4)

1. A film forming device, have: Vacuum tank; a hollow discharge container, arranged in the vacuum tank and provided with a plurality of discharge holes; a plurality of tubular introduction parts arranged in the hollow part of the release container; a gas supply unit that supplies raw material gas to each of the introduction units; and a substrate holding portion holding the substrate at a position facing the discharge hole of the discharge container, The outer peripheral side surface of each of the introduction parts is in close contact with the wall surface of the discharge container facing the hollow part, The discharge hole is arranged at a position opposite to the substrate, A through hole that communicates the inner space of the introduction part with the release hole is provided in the close contact part of each introduction part, and it is characterized in that, have: A plurality of sub-pipes are arranged in the hollow portion of the discharge container and a plurality of sub-through holes are provided on the outer peripheral side, and the outer peripheral parts of the sub-through holes on the outer peripheral side are in contact with the wall surface of the discharge container. leave; and a plurality of connecting pipes, one end of which is connected to the auxiliary through hole and the other end is connected to another discharge hole different from the discharge hole connected to the introduction part, and the secondary through hole is different from the discharge hole connected to the introduction part. the discharge hole connected to the introduction portion is connected to the other discharge hole, The gas supply part has first and second gas supply parts for releasing the first and second source gases, The introduction part is connected to the first gas supply part, and the sub-pipe is connected to the second gas supply part. 2 . The film forming apparatus according to claim 1 , wherein the introduction portions are arranged parallel to each other toward the wall surface of the discharge container and arranged at equal intervals on the wall surface of the discharge container. 3 . 3. The film forming apparatus according to claim 1, wherein the introduction part connected to the first gas supply part and the introduction part connected to the second gas supply part are alternately arranged in parallel on the wall of the release container. 4. The film forming apparatus according to any one of claim 1 or claim 2, wherein an inlet and an outlet are provided on the wall of the discharge container, and the temperature-controlled refrigerant flows from The introduction port is introduced into the hollow portion of the discharge container, and the refrigerant is discharged from the discharge port.