KR100422048B1 - side floe type shower ring injector - Google Patents

Abstract

The present invention defines a closed reaction space in which a wafer is seated therein, and includes a first supply pipe through which an end is introduced into the chamber to introduce external gaseous substances into the reaction space. A side flow type shower injector having a circular opening in the center and installed parallel to the wafer in the chamber to inject the gaseous material into the wafer, wherein the shower is formed along the outer edge of the opening. A first flow path line on the ring provided in the ring injector; A plurality of first injection holes penetrating the inner wall of the opening at equal intervals and communicating with the first flow path line, respectively; A second flow path line disposed outside the first flow line and having one end and the other end connected to the first flow line, respectively; A third flow path line disposed outside the first flow path line facing the center of the second flow path line and the opening, and having one end and the other end connected to the first flow line line, respectively; A fourth flow path line disposed outside the second flow path line and the third flow path line, the fourth flow path line having one end connected to the second flow path line and the other end connected to the third flow path line; It provides a shower injector having one end connected to the fourth flow line, the other end includes a fifth flow line connected to the end of the first supply pipe.

Description

Side floe type shower ring injector

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and in more detail, is installed in a chamber in which a sealed reaction area in which a wafer is placed is defined, and injects a gaseous material introduced from the outside into the wafer. The present invention relates to a shower ring injector of a side flow type.

In recent years, with the development of science, the field of new materials for the development and processing of new materials has been rapidly developed, and the results of their development are the driving force for the rapid development of the semiconductor industry. A semiconductor device is a large scale integration (LSI) that is realized through a process of depositing and patterning a plurality of thin films on an upper surface of a wafer, which is a substrate. The process proceeds in a process module including a chamber, which is a sealed reaction vessel.

FIG. 1 is a schematic cross-sectional view of a process module 10 for manufacturing a semiconductor, in which a wafer is placed inside and a thin film is deposited on an upper surface thereof or a sealed reaction region for patterning a previously deposited thin film is defined. The chamber includes a chamber, and a source and reactant supply unit 40 for storing and supplying a gaseous source and a reactant required for these processes to the chamber 20.

The chamber 20 is, for example, a top cover 20a having a dome shape convex upward with a material such as quartz, and a bottom box base having a metal box shape having an opening formed at an upper surface thereof. The 20b is coupled to define a space enclosed therein, and the chuck 50 is installed in the internal space to support the wafer 1 seated on the upper surface thereof. In addition, the chamber 20 includes a supply pipe 42 for receiving the gaseous material required for the process from the source and reactant supply unit 40, a discharge pipe 62 for discharging the internal gas, and a pump P installed at an end thereof. It includes a decompression means of.

When the wafer 1 is first transferred into the chamber 20 and seated on the upper surface of the chuck 30, and then the chamber 20 is sealed, it is then decompressed through a decompression means such as a pump P disposed at the end of the discharge pipe 62. After controlling the internal environment of the chamber 20, as the gaseous substances stored in the source and reactant supply 40 through the supply pipe 42 enter the chamber 20, the wafer 1 is chemically reacted with the gaseous substances. Processing and processing.

At this time, in order to more actively induce the reaction of the gaseous material is usually provided with an injector connected to the supply pipe 42 into the chamber 20 to evenly spread the gaseous material throughout the entire area in the chamber 20, such an injector The shape can be variously modified depending on the purpose.

For example, the side flow type shower injector 22 shown in the drawing is interposed between the lower base 20b and the upper cover 20a, and is installed to form a part of the side wall 20b-1 of the chamber 20. It is also called a gas ring because it has a ring shape with an opening formed in the center.

Referring to FIG. 2, which is a perspective view of only such a shower injector, it is installed in parallel with the wafer with a circular opening 24 at the center as described above to inject a gas material supplied from the outside to the wafer. An annular first flow path line 36 is provided in the shower injector 22 along the outer edge of the opening 24.

At this time, the side wall 26 of the opening is provided with a plurality of injection holes 26a penetrating through the first flow path line 36 of the annular, respectively, and the source of Figure 1 on the outer surface of the shower injector 22 And an inlet end 28a to which the supply pipe 42 connected to the gas supply unit 40 is connected, and at this time, a second flow path connecting the inlet end 28a and the flow line 36 into the shower injector 22. Line 28 is included.

Accordingly, the gaseous material discharged from the source and the reactant supply part 40 through the supply pipe 42 is along the inlet 28a of the showering injector 22 and the first flow path 28 therein. Injected into 36, and then the gas material is injected through the plurality of injection holes (26a) above the wafer (see Fig. 1).

However, the general side-flow showering injector 22 having the above-described configuration has some problems in use, in which the gaseous material delivered through the inlet 28a and the second flow line 28 is the first flow path. As it is not evenly distributed in the line 36, the injection pressure is concentrated in the injection hole 26a at a specific position.

That is, the pressure of the gaseous material supplied to the inflow end 28a and the second flow path line 28 is concentrated to the A portion where the injection hole 26a closest to it is located, and the injection hole 26a of the other portion thereof. The injection pressure of the branch is markedly different. This has the disadvantage of reducing the uniformity by differentiating the degree of processing of the wafer as the concentration of the reaction gas only on one side from the perspective of the wafer.

In the semiconductor manufacturing process, an atomic layer deposition method has been developed, which is abbreviated as ALD (ALD: ALD) as a method of depositing a thin film on the upper surface of a wafer through a chemical reaction of a gaseous substance. This is widely used because it is possible to realize a high purity thin film and to realize a thin film having excellent uniformity and step coverage characteristics.

This may be similar to the general chemical vapor deposition (CVD) method in that a chemical reaction between two or more gaseous materials is used. However, a general chemical vapor deposition method is generally used in a plurality of gaseous materials into a reaction zone where a wafer exists. In contrast to depositing the reaction products by stacking them on the surface from above the wafer at the same time, there is a big difference in that the location of the chemical reaction between the gaseous materials is limited only to the wafer surface. Therefore, this atomic layer deposition method is to introduce different gaseous materials into the chamber sequentially, at which time purge process to remove the remaining gaseous material in the chamber before and after the introduction of the respective reactive gas material must be carried out.

When the atomic layer deposition method proceeds to the chamber in which the above-described general side flow type showering injector is installed, the injection hole is formed through the inlet end 28a and the second flow path line 28 and the first flow path line 36. The gaseous material injected into the (26a) is four kinds of gaseous materials are sequentially repeated, each of which can remove the first gas and the second gas and the residual gas in the chamber to react with each other to produce a compound It is divided into a first purge gas and a second purge gas which is an inert gas, and the inflow order thereof includes a first reactor body, a first purge gas, a second reactor body, and a second purge gas.

However, each of these gaseous substances share one inflow end 28a, the second flow path line 28, the first flow path line 36, and the injection hole 26a, which are the same paths. Alternatively, if the second purge gas is not sufficient, the first or second reactor may be left in the shower injector 22, which may then react with the incoming second or first reactor to shower the injector 22. It will condense the compound within.

These condensation compounds block the injection hole 26a of the shower injector 22 or act as an impurity when introduced into the chamber, thereby reducing the reliability of the semiconductor device. This will purge residual gas in the chamber and shower injector over a long period of time. However, this prolongation of the purge time is a fatal disadvantage in the low productivity atomic layer deposition method.

The present invention has been made in order to solve the above problems, it is possible to evenly spray the gaseous material supplied from the outside into the chamber, especially when used in the atomic layer deposition method, it is possible to suppress the reaction occurring inside the injector, It is an object of the present invention to provide a more improved side flow shower injector.

1 is a schematic cross-sectional view of a typical chambered process module

2 is a perspective view of a side flow shower injector installed in a general chamber type process module;

3 is a perspective view of a side flow shower injector according to the present invention;

4 is a plan view of a side flow shower injector according to the present invention;

5 is a cross-sectional view illustrating a cross section taken along the line V-V of FIG. 4.

<Description of the symbols for the main parts of the drawings>

122: showering injector 124: opening

126: inner wall 126a: first injection hole

126b: second injection hole 128: first flow line

130: second flow line 130a: second flow line

130b: other end of second euro line 132: third euro line

132a: third euro line once 132b: third euro line the other end

134: fourth euro line 134a: fourth euro line once

134b: other end of fourth euro line 136: fifth euro line

138a: first incoming end 138b: second incoming end

In order to achieve the above object, the present invention defines a closed reaction space in which a wafer is seated therein, and a first end of which is introduced into the chamber to introduce an external gaseous material into the reaction space. A chamber including a supply pipe, comprising: a side flow type shower ring having a circular opening in the center and installed in parallel with a wafer in the chamber to inject the gaseous material into the wafer. A first flow path line on the ring provided through the shower injector along the outer edge of the opening; A plurality of first injection holes penetrating the inner wall of the opening at equal intervals and communicating with the first flow path line, respectively; A second flow path line disposed outside the first flow line and having one end and the other end connected to the first flow line, respectively; A third flow path line disposed outside the first flow path line facing the center of the second flow path line and the opening, and having one end and the other end connected to the first flow line line, respectively; A fourth flow path line disposed outside the second flow path line and the third flow path line, the fourth flow path line having one end connected to the second flow path line and the other end connected to the third flow path line; It provides a shower injector having one end connected to the fourth flow line, the other end includes a fifth flow line connected to the end of the first supply pipe.

In this case, the other end of the second flow path is connected to a point 1/4 of the first flow path line based on one end of the second flow path line, and one end of the third flow path line is one end of the second flow path line. The second flow path is connected to a point that is 1/2 of the first flow path line, and the other end of the third flow path line is connected to a third quarter of the first flow path line based on one end of the second flow path line. And one end of the fourth flow path line is connected to an intermediate point of the second flow path line, and the other end of the fourth flow path line is connected to an intermediate point of the third flow path line. One end of the five flow path lines may be connected to an intermediate point of the fourth flow line.

In this case, the first to fourth flow path lines have the same cross-sectional area and are arranged on the same plane.

In another aspect, the chamber further comprises a second supply pipe for introducing an external gaseous material into the reaction space, wherein the showering injector is formed on the ring through the inside of the showering injector along the outer edge of the opening A sixth flow line; A plurality of second injection holes arranged at equal intervals so as to communicate with the sixth flow path lines through the inner wall of the opening; A seventh flow path line disposed outside the sixth flow path line and having one end and the other end connected to the sixth flow line line, respectively; An eighth flow path line disposed outside the sixth flow path line so as to face the center of the seventh flow path line and the opening, and one end and the other end connected to the sixth flow path line, respectively; A ninth flow path line disposed outside the seventh flow line and the eighth flow path line, the ninth flow path line having one end connected to the seventh flow path line and the other end connected to the eighth flow path line; A showering injector having one end connected to the ninth flow path line and the other end connected to the end of the second supply pipe is further provided.

In this case, the other end of the seventh flow path is connected to a point 1/4 of the sixth flow path line based on one end of the seventh flow path line, and one end of the eighth flow path line is one end of the seventh flow path line. The other end of the eighth flow path is connected to a point three quarters of the sixth flow line based on one end of the seventh flow line. And one end of the ninth flow path line is connected to an intermediate point of the seventh flow path line, and the other end of the ninth flow path line is connected to an intermediate point of the eighth flow path line. One end of the 10-channel line is connected to the intermediate point of the ninth channel line.

In addition, the first injection holes are arranged at the same height on the inner wall of the opening, and the first to fourth flow path lines have the same cross-sectional area and are arranged on substantially the same plane as the plurality of first injection holes. The second injection holes are arranged at substantially the same height at the lower end of the inner wall of the opening, and the sixth to ninth flow path lines have the same cross-sectional area and are arranged on substantially the same plane as the plurality of second injection holes. Now, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The side flow type shower injector according to the present invention is installed in a chamber having a closed reaction space in which a wafer is seated therein, and performs a function of diffusing and spraying gas material supplied from the outside to the wafer. In the same manner as in the general case, a ring shape having a circular opening in the inner center thereof is placed parallel to the wafer.

In this case, the shower injector according to the present invention may be installed such that the inner wall of the opening forms a part of the inner wall of the chamber, but it will be apparent to those skilled in the art that the showering injector may be interposed horizontally with the wafer in the reaction zone independently of the chamber.

Hereinafter, referring to FIG. 3 and a plan view of FIG. 3, which is a perspective view of only a side flow type shower injector according to the present invention, it has been described above that it has a circular opening 124 at an inner center thereof.

In this case, a plurality of first injection holes 126a are installed in the inner wall 126 of the opening 124, and the gaseous material supplied from the outside to the shower injector 122 according to the present invention finally receives these first injection holes 126a. Diffusion flow into the wafer through a plurality of flow paths, and a plurality of flow paths are installed in the shower injector 122 according to the present invention for uniform injection pressure of the gaseous materials to be injected into the first injection holes 126a. .

Each of these flow path lines penetrates into the shower injector 122 along the outer edge of the central opening 124, so as to communicate with the plurality of first injection holes 126a described above, respectively. )and; One end 130a and 132a and the other end 130b and 132b are connected to the first flow line 128 in a state in which they are spaced apart from the center of the opening 124 along the outer side of the first flow line 128. Second and third flow path lines 130 and 132 to be formed; A fourth having an end 134a connected to the second flow line 130 and the other end 134b connected to the third flow line 132 outside the second and third flow line lines 130 and 132. A flow line 134; One end includes a fifth flow path line 136 connected to the fourth flow line 134, and the other end of the fifth flow line 136 is a showering injector 122 so that an external first supply pipe may be connected. It is connected to the first leading end 128a formed on the outer surface of the.

Therefore, the gaseous material introduced from the outside through the first supply pipe first passes through the first inlet end 128a and the fifth flow path line 136 of the shower injector 122 according to the present invention. Each gaseous material flows through the two flow paths, and each of the gaseous substances is again at both ends of the second flow path line 130 and the third flow path line 132 at one end 134a and the other end 134b of the fourth flow path line 134. Flows through the distribution. Thereafter, these gaseous substances are finally introduced into the first flow path line 128 to be diffused and injected into the chamber through the first injection hole 126a.

In this case, in order to give the same injection pressure to each of the plurality of first injection holes 126a, the first to fourth flow path lines 128, 130, 132, and 134 are each provided on the same plane with the same cross-sectional area. One end 130a and the other end 130b of the second flow line 130 connected to the first flow line 128 and the one end 132a and the other end 132b of the third flow line 132 are respectively. It is preferable to connect at exactly the point where the first flow path line 128 is divided into four.

That is, when it is displayed in the time direction for convenience of explanation, if the portion where one end 130a of the second flow path line 130 and the first flow path line 128 are connected to the 0 o'clock direction, the other end 130b thereof ) Is reconnected to the first flow line 128 at 3 o'clock, and one end 132a and the other end 132b of the third flow line 132 are respectively connected to the first flow line 128 at 6 and 9 o'clock. It is preferable to connect with). In other words, the other end 130b of the second flow path line 130 is connected to a point 1/4 of the first flow path line 128, and the third flow path line 132 has an opening. Since it is assumed that the second flow path line 130 is symmetrical with each other along the center of the center 124, one end 132a of the third flow path line 132 ends one end 130a of the second flow path line 130. As a reference, it is connected to a point that is 1/2 of the first flow path line 128, and the other end thereof 132b is connected to a point that becomes 3/4 of the first flow path line 128.

Accordingly, the second and third flow path lines 130 and 132 have a length equal to one fourth of the first flow line line 128 and are installed on the outside thereof so that both ends thereof are connected to the first flow line line 128, respectively.

In addition, the fourth flow path line 134 communicating with each other on the outside of the second flow path line 130 and the third flow path line 132 is an intermediate between the second flow path line 130 and the third flow path line 132. Each end has one end 134a and the other end 134b, and thus the fourth flow line 134 surrounds the outer half of the first flow line 128. One end of the five flow line 136 is connected.

Therefore, since the gaseous material supplied to the inlet end is supplied to the intermediate point of the fourth flow path line 134 by the first fifth flow line 136, the gas material is distributed in equal amounts, respectively, to the second and third flow path lines 130 and 132. Inflow.

In addition, since the portion connected to one end 134a of the fourth flow line 134 is an intermediate point of the second flow line 130, the gaseous material supplied through one end of the fourth flow line 134 is also the second flow line. The same amount is distributed and flows to both ends of the 130, and finally, it is introduced into the first flow path line 128. At this time, the third flow line 132 is also the portion connected to the other end 134b of the fourth flow line 134 is a middle point thereof, which is also distributed in the same amount through the first end 132a and the other end 132b, respectively. A gaseous substance is introduced into one flow path line 128.

For example, when the amount of gaseous material supplied to the first inlet end 138a and the fifth flow path line 136 of the showering injector 122 according to the present invention is 100, this is the middle of the first fourth flow line 134. Each half is divided by 50 at the point and flows to one end 134a and the other end 134b, and the 50 divided gas materials are separated by 25 at the intermediate points of the second flow line 130 and the third flow line 132, respectively. It is split in half and flows through them. Therefore, the first flow path line 128 is, at the same time, the gaseous material of 25 at each of its quarters at the same time, after which they are injected at the same pressure through a plurality of first injection holes (126a).

At this time, it is installed between the first flow path line 128 and the second and third flow path lines (130, 132), one end (130a, 132a) and the end (130b) of the second and third flow path lines (130, 132), It may be considered that 132b) is further provided with four sub- euro lines, each of which has its own intermediate point connected to each other, and whose ends are connected to the first flow line 128 at eight equal points. The injection pressure of the gaseous substance applied to the first injection hole 126a may be more evenly distributed, but since the configuration of the apparatus becomes too complicated, it is preferable that the first to fifth flow path lines (refer to the drawings and the foregoing description) Showering injectors 122 equipped with 128, 130, 132, 134, 136 would be suitable.

In addition, the showering injector 122 according to the present invention can be expected to have an improved effect when used in the atomic layer deposition method, in which case the first to fifth flow path line 128 having the same cross-sectional area and arranged on the same plane; With a plurality of second injection holes 126b penetrating the inner wall 126 of the opening 124 at the lower end of the first injection hole 126a in the state of dividing the 130, 132, 134, and 136 up and down, respectively, The first injection hole 126a is connected to the first flow path line at the upper end and the second injection hole 126b is connected to the first flow path line at the lower end, respectively. This is equivalent to arranging the first to fifth flow paths 128, 130, 132, 134, and 136 symmetrically to each other while sharing one opening 124, that is, the aforementioned FIG. Or it can be said that the same structure as 4 is installed on each back.

In this case, for convenience, the elements arranged on the rear surfaces of the first to fifth flow path lines 128, 130, 132, 134, and 136 described above in the east are respectively disposed on the sidewalls of the opening 124. The plurality of first injection holes 126a may also be divided into a first injection hole 126a communicating with the first flow path line 128 and a second injection hole 126b communicating with the sixth flow path line. The opening 124 penetrates through the top and bottom of the side wall so as to be arranged in multiple layers.

In addition, although not shown, it is preferable that the supply pipe for supplying the gaseous substance is also divided into first and second supply pipes for supplying the first reactor body and the second reactor body, respectively. A first lead end 138a is connected to a second lead end 138b, indicated at 128b in FIG.

The gaseous material of the first supply pipe is injected through the first injection hole 126a via the first inlet 138a and the first to fifth flow path lines 128, 130, 132, 134, and 136, respectively. The gaseous material of the second supply pipe is injected through the second injection hole 126b via the second inlet end 138a and the sixth through tenth flow path lines, respectively.

In this case, it will be apparent to those skilled in the art that it is advantageous to supply the first reactor body and the first purge gas to the first supply pipe, and the second reactor body and the second purge gas to the second supply pipe.

That is, referring to FIG. 5, which is a cross-sectional view taken along the VV line of FIG. 3, the shower injector 122 according to the present invention has first and second flow paths 128 and 130 and a fourth flow path at an upper end thereof. A line 134 is provided, and at the lower end thereof, sixth and seventh flow lines 128a and 130b and a ninth flow path line 134a are provided, and they can be confirmed that they are arranged in two layers. In addition, the first passage line 128 communicates with the first injection hole 126a penetrating the upper end of the inner wall 126 of the opening 124, and the sixth passage line 128a has the inner wall 126 of the opening 124. It communicates with the 2nd injection hole 126b which penetrated at the lower end.

Therefore, when the side flow shower injector 122 according to the present invention is used in the atomic layer deposition method with the advantage of giving an even injection pressure to the plurality of first and second injection holes (126a, 126b), Since the inflow paths of the respective reactive gas materials are different, problems due to the gaseous materials remaining therein can be solved.

The showering injector according to the present invention can apply a uniform spray pressure to the plurality of ejection holes, thereby making it possible to spray the gas material evenly on the front surface of the wafer. This has the advantage of enabling the fabrication of semiconductor devices with improved film quality, and especially when applied to atomic layer deposition methods, by varying the inflow path of the respective reactant materials within the injectors that are common in common shower injectors. It has the advantage of controlling the reactant condensation effectively.

Claims (12)

A chamber defining a closed reaction space in which a wafer is seated therein and including a first supply pipe through which an end is introduced into the chamber to introduce external gaseous substances into the reaction space. A side flow type shower ring having a circular opening in the chamber and installed in parallel with a wafer in the chamber to inject the gaseous material into the wafer, A first flow path line on the ring provided through the shower injector along the outer edge of the opening; A plurality of first injection holes penetrating the inner wall of the opening at equal intervals and communicating with the first flow path line, respectively; A second flow path line disposed outside the first flow line and having one end and the other end connected to the first flow line, respectively; A third flow path line disposed outside the first flow path line facing the center of the second flow path line and the opening, and having one end and the other end connected to the first flow line line, respectively; A fourth flow path line disposed outside the second flow path line and the third flow path line, the fourth flow path line having one end connected to the second flow path line and the other end connected to the third flow path line; A fifth flow path line having one end connected to the fourth flow line and the other end connected to an end of the first supply pipe; Shower injector comprising The method according to claim 1, The first to fourth flow path lines having the same cross-sectional area and showering injector arranged on the same plane The method according to claim 1, The other end of the second flow path line is connected to a point 1/4 of the first flow path line with respect to one end of the second flow path line, and one end of the third flow path line connects one end of the second flow path line. A shower connected to a point half of the first flow line, and the other end of the third flow line is connected to a point three quarters of the first flow line based on one end of the second flow line. Ring injector The method according to claim 3, One end of the fourth flow line is connected to the intermediate point of the second flow line and the other end of the fourth flow line injecting shower injector is connected to the middle point of the third flow line The method according to claim 4, One end of the fifth flow line is a showering injector connected to the intermediate point of the fourth flow line The method according to any one of claims 3 to 5, The first to fourth flow path lines having the same cross-sectional area and showering injector arranged on the same plane The method according to claim 1, The chamber further includes a second supply pipe for introducing an external gaseous material into the reaction space, The showering injector, A sixth flow path line on the ring extending through the shower injector along the outer edge of the opening; A plurality of second injection holes arranged at equal intervals so as to communicate with the sixth flow path lines through the inner wall of the opening; A seventh flow path line disposed outside the sixth flow path line and having one end and the other end connected to the sixth flow line line, respectively; An eighth flow path line disposed outside the sixth flow path line so as to face the center of the seventh flow path line and the opening, and one end and the other end connected to the sixth flow path line, respectively; A ninth flow path line disposed outside the seventh flow line and the eighth flow path line, the ninth flow path line having one end connected to the seventh flow path line and the other end connected to the eighth flow path line; A tenth flow path line having one end connected to the ninth flow path line and the other end connected to an end of the second supply pipe; Showering injector further comprising The method according to claim 7, The first injection holes are arranged at the same height at the upper end of the inner surface of the opening, the first to fourth flow path lines have the same cross-sectional area and are arranged on substantially the same plane with the plurality of first injection holes, The second injection holes are arranged at substantially the same height at the lower end of the inner surface of the opening, and the sixth to ninth flow path line has the same cross-sectional area and the shower ring arranged on the substantially same plane with the plurality of second injection holes Injector The method according to claim 8, The other end of the seventh flow line is connected to a point 1/4 of the sixth flow line based on one end of the seventh flow line. One end of the eighth flow path is connected to a point half of the sixth flow line based on the one end of the seventh flow line, and the other end of the eighth flow path is based on one end of the seventh flow line. Shower injector connected to the third quarter of the sixth flow line The method according to claim 9, One end of the ninth flow path line is connected to the intermediate point of the seventh flow path line and the other end of the ninth flow path line injector is connected to the intermediate point of the eighth flow path line The method according to claim 10, One end of the tenth flow line is a showering injector connected to an intermediate point of the ninth flow line The selected claim of claim 8, wherein The first injection holes are arranged at the same height at the upper end of the inner surface of the opening, the first to fourth flow path lines have the same cross-sectional area and are arranged on substantially the same plane with the plurality of first injection holes, The second injection holes are arranged at substantially the same height at the lower end of the inner surface of the opening, and the sixth to ninth flow path line has the same cross-sectional area and the shower ring arranged on the substantially same plane with the plurality of second injection holes Injector