WO2006090537A1

WO2006090537A1 - Gas mixer, film deposition equipment, and method for producing thin film

Info

Publication number: WO2006090537A1
Application number: PCT/JP2006/300751
Authority: WO
Inventors: Yutaka Miura
Original assignee: Hoya Advanced Semiconductor Technologies Co., Ltd.
Priority date: 2005-02-22
Filing date: 2006-01-19
Publication date: 2006-08-31
Also published as: JP2008114097A

Abstract

A gas mixer having at least two mixing chambers in which the first mixing chamber is provided with two or more openings for introducing two or more kinds of gas being mixed and one or more discharge opening, and the second mixing chamber is provided with one or more openings communicating with the discharge opening of the first mixing chamber and introducing gas discharged from the first mixing chamber and one or more discharge opening, the discharge openings provided in the first mixing chamber and/or second mixing chamber being arranged so as not to overlap the introduction opening provided in the same mixing chamber in the direction of gas flow. A gas mixer applicable to a variety of film deposition conditions can be provided without causing complication of the equipment or increase in size. A film deposition equipment employing it, and a method for forming a thin film having high in-plane uniformity are also provided.

Description

Specification

Gas mixer, film forming apparatus, and thin film manufacturing method

Technical field

[0001] The present invention relates to a gas mixer used when supplying two or more kinds of gases (source gas, carrier gas, dilution gas, etc.) to various film forming apparatuses, a film forming apparatus using the same, and a thin film It relates to the manufacturing method.

Background art

Conventionally, a CVD (chemical vapor deposition) method, a sputtering method, or the like has been adopted as a method for forming a thin film on a substrate by introducing two or more gases into a film forming apparatus. .

The CVD method is a method in which two or more kinds of source gases are introduced into a film forming chamber and a thin film is formed on a substrate by a chemical reaction between the source gases.

Sputtering is a method of forming a thin film on a substrate by blowing a gas onto a target made of metal or the like and attaching the ejected molecules to the surface of the substrate. A reactive sputtering method using gas is also used. In general, sputtering is used in semiconductor manufacturing processes and the like because it is easy to form a uniform and high-quality film.

[0003] As a method for introducing two or more kinds of gases into a CVD apparatus or a sputtering apparatus, the following methods (1) to (3) are generally used.

(1) A method in which each gas pipe is directly connected to the device, and two or more gases are separately introduced into the device.

(2) A method of previously connecting two gas pipes into a single pipe and combining the two pipes into two or more gases into the apparatus (for example, see Non-Patent Document 1). ).

(3) A method in which each gas pipe is connected in advance to a gas mixing device, and two or more gases are mixed by the gas mixing device and then introduced into the device (for example, refer to Patent Document 1).

[0004] Non-Patent Document 1: “CVD Handbook”, Chemical Engineering Society, Asakura Shoten, p727-728

Patent Document 1: Japanese Patent Laid-Open No. 11 19494

Disclosure of the invention Problems to be solved by the invention

[0005] Meanwhile, in recent years, with the increase in the density of semiconductor devices and the increase in the diameter of the substrate, there are strict requirements for the thickness of the thin film formed on the substrate and the uniformity of the film quality. In other words, as the density of semiconductor devices increases, the line width of the device becomes narrower, and the ratio of the film thickness to the line width increases, making it impossible to ignore film thickness and film quality uniformity. And when the line width is wide, even if it is a film thickness distribution or film quality distribution that would not have been a problem if averaged over the entire area, even if the line width is narrow, the film itself Therefore, high uniformity of film thickness and film quality is required.

[0006] Here, for example, the resistance value which is one of the important factors of the film quality depends on the volume of the film.

For this reason, in the case of a wide line width, the control of the line width uniformity is more important than the film thickness uniformity in controlling the film volume. On the other hand, when the line width is narrow, the uniformity of the film thickness is more important than the uniformity of the line width in controlling the film volume.

Other factors relating to the film quality include pressure resistance and etching characteristics. Needless to say, the demand for in-plane uniformity is becoming stricter in these characteristics as well.

[0007] As described above, even with a film thickness at a level that has not been a problem until now or an in-plane distribution of film quality, it has become a situation that cannot be ignored as the density of semiconductor devices increases. In addition, as the substrate diameter increases, in-plane uniformity of film thickness and film quality is required over a larger area.

[0008] However, even if a conventionally used gas introduction method is employed, it has become difficult to satisfy recent demands for film thickness and film quality uniformity. This problem has become more prominent as the substrate diameter increases.

[0009] For example, when the method (1) is adopted and a film is formed on a deposition target substrate, the formed film has an in-plane distribution (in-plane film thickness distribution, in-plane composition distribution, etc.). There was a problem.

As a result of examining the cause of this in-plane distribution, the present inventor has found that it depends on the arrangement of the gas introduction pipe to the apparatus. That is, when two or more gases were introduced into the apparatus by the method (1) above, it was found that mixing alone in the apparatus was substantially insufficient. That is, when mixing each gas by the method (1) above, it is necessary to lengthen the gas flow path from introduction into the apparatus to the film formation process. In order to lengthen the length, it is necessary to enlarge the apparatus. For this reason, it is difficult to form a uniform film by the method (1), which is practically impossible.

[0010] Further, the method (2) is considered to correspond to the method (1) above in which the gas flow path until the gas is mixed is secured outside the apparatus and the gas flow path is lengthened. However, even in this case, the mixing of the gases is insufficient, and the in-plane distribution of the film formed on the deposition target substrate is not eliminated.

[0011] Further, as a method of the above (3), Patent Document 1 discloses that a mixing pipe for flowing a raw material gas and an argon gas through the main pipe and an oxygen gas is provided on the same circumference of the main pipe. It is shown how to mix the raw material gas' argon gas · oxygen gas (however, the gas flow rate of the main pipe must be higher than the gas flow rate of the mixed pipe).

[0012] However, in this method, since the gas flowing through the main pipe and the mixed pipe force gas ejected from three directions are mixed by colliding with each other at the center of the main pipe, In the mixer, the gas from two systems (the gas system flowing through the main pipe and the gas system flowing through the mixing pipe) can only be mixed into one system.

That is, for example, in order to mix three or more gas systems, it is necessary to use a plurality of mixers as shown in Patent Document 1, which leads to complicated and large equipment. This is not preferable.

[0013] Furthermore, in the method of Patent Document 1, it is necessary to optimize the structure of the mixer (pipe position, pipe diameter, etc.) according to the film formation conditions, so gas species having greatly different molecular weights are mixed. In this case, it is difficult to use a single mixer for various film formation conditions, such as mixing gas types with significantly different flow rates, or changing the gas flow rate during the process. It is necessary to design a mixer according to the conditions, and it is difficult to apply it to diversification of gas types and film formation conditions.

[0014] The present invention has been made based on such a technical background, and is a gas mixer that can be applied to various film forming conditions without incurring complexity and size of the apparatus. The purpose is to provide a film-forming device using the above. The present invention also provides a thin film capable of forming a thin film with high in-plane uniformity. The purpose is to provide a manufacturing method.

Means for solving the problem

In order to achieve the above object, the gas mixer of the present invention is a gas mixer for mixing two or more kinds of gases, and is a first mixing chamber located upstream in the gas flow direction. And at least a second mixing chamber located downstream, wherein the first mixing chamber has two or more inlets into which two or more gases to be mixed are introduced, and one or more exhaust ports. And an outlet, and the second mixing chamber communicates with an exhaust port provided in the first mixing chamber, and includes at least one gas into which the gas discharged from the first mixing chamber is introduced. An introduction port and a discharge port more than that are provided. The discharge loca provided in the first mixing chamber and / or the second mixing chamber. With respect to the introduction port provided in the same mixing chamber, In the gas flow direction, they are arranged so that they overlap.

[0016] By adopting such a configuration, two or more gases can be uniformly mixed with a simple structure that does not increase the complexity and size of the apparatus.

[0017] The gas mixer of the present invention is preferably configured so that the pressure of the second mixing chamber is lower than the pressure of the first mixing chamber when two or more gases are mixed. More specifically, the volume of the second mixing chamber is preferably larger than the volume of the first mixing chamber. Also, the discharge port provided in the first mixing chamber and / or the first mixing chamber. It is preferable that the total area of the inlets provided in the two mixing chambers is 1/5 or less of the area of each installation surface.

By adopting such a configuration, when the gas discharged from the first mixing chamber is introduced into the second mixing chamber, an adiabatic expansion effect can be obtained, and mixing by the diffusion process is effectively generated. It becomes possible to make it.

[0018] In addition, the gas mixer of the present invention may be provided with at least two or more mixing chambers. However, in the case where two mixing chambers are provided, the second mixing chamber has two or more mixing chambers. A structure having a discharge port and connecting the pipes connected to each of the discharge ports may be combined into a single pipe.

Further, the first mixing chamber is provided with one or more inlets through which the gas discharged from the second mixing chamber is introduced, and at least one discharge port that communicates with the outlet provided in the second mixing chamber. As a configuration including three mixing chambers, three mixing chambers may be provided.

[0019] Further, the gas mixer of the present invention may be provided with a temperature adjusting mechanism so that a stable mixed state can be ensured regardless of the temperature change of the outside air.

[0020] Further, a film forming apparatus of the present invention includes the gas mixer as described above, and is arranged in the film forming chamber by supplying two or more kinds of gases into the film forming chamber. A film forming apparatus for forming a thin film on a substrate, comprising: a gas supply pipe for supplying two or more kinds of gases mixed in the film forming chamber; Connected to a gas supply source via a mixer, the gas mixer comprising at least a first mixing chamber located upstream in a gas flow direction and a second mixing chamber located downstream; The one mixing chamber is provided with two or more inlets through which two or more kinds of gases to be mixed are introduced, and one or more outlets, and the second mixing chamber has the first mixing chamber. The gas discharged from the first mixing chamber communicates with the discharge port provided in one mixing chamber. One or more inlets to be introduced and one or more outlets are provided, and the outlets provided in the first mixing chamber and / or the second mixing chamber are introduced in the same mixing chamber It can be set as the structure arrange | positioned so that it may not overlap with the opening | mouth in the gas flow direction.

[0021] The thin film manufacturing method of the present invention is a thin film manufacturing method in which two or more kinds of gases are supplied to a film forming apparatus to form a thin film on a substrate disposed in the film forming apparatus, At least a first mixing chamber located upstream in the gas flow direction and a second mixing chamber located downstream are provided, and two or more kinds of gases to be mixed are contained in the first mixing chamber. There are provided two or more inlets and one or more outlets to be introduced, respectively, and the second mixing chamber communicates with an outlet provided in the first mixing chamber, and One or more inlets for introducing the gas discharged from the mixing chamber and one or more outlets are provided, and the outlet provided in the first mixing chamber and / or the second mixing chamber Are arranged so that they do not overlap in the gas flow direction with respect to the inlet provided in the same mixing chamber. This is a method of forming a thin film on the substrate by supplying two or more kinds of mixed gases to the film forming apparatus via the gas mixer.

With such a method, a thin film with high in-plane uniformity can be easily produced. [0023] More specifically, in the thin film manufacturing method of the present invention, a mixed gas containing at least a silicon source gas and a carbon source gas is supplied to a film forming apparatus to form a silicon carbide film on the substrate. It can be a method of forming.

The invention's effect

[0024] As described above, according to the present invention, two or more gases can be uniformly mixed with a simple structure without increasing the complexity and size of the apparatus. For this reason, it is possible to easily manufacture a thin film with high in-plane uniformity by supplying two or more kinds of uniformly mixed gases to the film forming apparatus.

Brief Description of Drawings

FIG. 1 is a schematic perspective view showing an embodiment of a gas mixer according to the present invention.

FIG. 2 is a schematic perspective view showing a modification of the embodiment of the gas mixer according to the present invention.

FIG. 3 is an explanatory diagram showing an outline of an embodiment of a film forming apparatus according to the present invention.

FIG. 4 is a cross-sectional view taken along line AA in FIG.

FIG. 5 is an explanatory diagram showing the arrangement of gas supply pipes in the film forming apparatus used in Comparative Example 1.

Explanation of symbols

[0026] 1 Gas mixer

10 First mixing chamber

20 Second mixing chamber

30 Third mixing chamber

12a-12d, 22a, 22b, 32a, 32b inlet

14a, 14b, 24a, 24b, 34a outlet

40 Piping (gas supply pipe)

100 Deposition system

110 Deposition chamber

150 substrates BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the following description is merely an example of the present invention, and the technical scope of the present invention is not limited by the following description.

[0028] [Gas mixer]

First, an embodiment of a gas mixer according to the present invention will be described. Here, FIG. 1 is a perspective view showing an outline of the gas mixer in the present embodiment.

The gas mixer 1 shown in FIG. 1 includes three mixing chambers, a first mixing chamber 10, a second mixing chamber 20, and a third mixing chamber 30, and these mixing chambers 10, 20, 30 are Both have a hollow structure with a substantially cylindrical shape.

Note that the arrows in the figure indicate the gas flow directions when mixing two or more gases using the gas mixer 1 in the present embodiment. Gas flows in the order of chamber 20 and third mixing chamber 30.

[0030] In the present embodiment, the first mixing chamber 10 includes an inlet arrangement surface 12 on the upstream side of the gas flow, and an outlet arrangement substantially parallel to the introduction port arrangement surface 12 on the downstream side. With face 14

. The normal directions of these surfaces 12 and 14 are made to substantially coincide with the gas flow direction.

[0031] A plurality of (two or more) inlets 12a are connected to the inlet arrangement surface 12 and connected to a pipe (not shown) to separately introduce two or more different gases into the first mixing chamber 10. , 12b, 12c, 12d. The number of introduction ports to be formed in the introduction port arrangement surface 12 can be changed as appropriate in consideration of the number of types of gas to be mixed and the characteristics of the gas to be mixed.

[0032] In the illustrated example, the discharge port arrangement surface 14 is provided with two discharge ports 14a and 14b. At this time, the discharge ports 14a and 14b are extended along the gas flow direction of each of the four introduction ports 12a, 12b, 12c, and 12d formed in the introduction port disposition surface 12 as illustrated. (Extended lines that pass through the centers of the inlets 12a, 12b, 12c, and 12d are indicated by two-dot broken lines in the figure), and the outlets 14a and 14b are in the gas flow direction. In addition, the power to make the level not overlap with the level difference of the inlets 12a, 12b, 12c, 12d. Les.

Note that the number of discharge ports formed in the discharge port disposition surface 14 is not limited to the illustrated example, and can be changed as appropriate.

[0033] Similarly, the second mixing chamber 20 includes an introduction port arrangement surface 22 on the upstream side of the gas flow, and a discharge port arrangement surface 24 substantially parallel to the introduction port arrangement surface 22 on the downstream side. The normal direction of faces 22 and 24 is

The gas flow direction substantially coincides with the gas flow direction.

[0034] On the introduction port arrangement surface 22 of the second mixing chamber 20, the introduction port 22a for introducing the gas discharged from the discharge ports 14a, 14b of the first mixing chamber 10 into the second mixing chamber 20 22b has been drilled.

[0035] In the illustrated example, the inlets 22a and 22b are communicated with the outlets 14a and 14b of the first mixing chamber 10 via pipes 40a and 40b provided along the gas flow direction. Force The inlet 22a, 22b and the outlets 14a, 14b are mixed with the force S. The mixing surface 22 of the second mixing chamber 20 and the outlet 14 of the first mixing chamber 10 are mixed. The pipes 40a and 40b can be omitted by making the inlets 22a and 22b and the outlets 14a and 14b communicate directly with each other while ensuring tightness in the chambers 10 and 20. By doing so, the mixer 1 can be miniaturized and the structure can be simplified.

[0036] The number of outlets of the first mixing chamber 10 and the number of inlets of the second mixing chamber 20 are usually the same, but the outlet of the first mixing chamber 10 and the second mixing chamber 20 are the same. The number of outlets of the first mixing chamber 10 and the number of inlets of the second mixing chamber 20 can be made different by collecting or branching the pipes connecting to the inlets of the second halfway. it can.

[0037] In the example shown in the drawing, two discharge ports 24a and 24b are formed in the discharge port disposition surface 24 of the second mixing chamber 20. Similarly to the case of the first mixing chamber 10, the discharge ports 24a and 24b are also arranged at positions away from the extended lines of the two introduction ports 22a and 22b of the introduction port arrangement surface 22 (introduction ports 22a and 22b). The extension lines that pass through the center of each 22b are also indicated by the two-dot broken lines in the figure), and the outlets 24a and 24b force in the direction of gas flow should be such that both the inlet 22a and 22b and the deviation do not overlap. It is.

Furthermore, in the second mixing chamber 20 as well, the number of introduction ports drilled in the introduction port arrangement surface 22 and the number of discharge ports drilled in the discharge port arrangement surface 24 can be appropriately changed. Introduce as an example When two inlets 22a, 22b are drilled in the outlet arrangement surface 22, and two outlets 24a, 24b are also drilled in the outlet outlet surface 24, the center of the two inlets 22a, 22b So that the direction connecting the centers of the two outlets 24a and 24b (also indicated by the dashed line in the figure) is almost perpendicular to the direction connecting the two outlets 24a and 24b. And outlets 24a, 24b are preferably provided.

In addition, although not particularly illustrated, when one discharge port is to be drilled on the discharge port arrangement surface 24, it is at a position that is approximately equidistant from each introduction port drilled in the introduction port arrangement surface 22. It is preferable to provide a discharge port.

[0039] Similarly, the third mixing chamber 30 includes an inlet arrangement surface 32 on the upstream side of the gas flow and an outlet arrangement surface 34 substantially parallel to the introduction port arrangement surface 32 on the downstream side. The normal direction of the surfaces 32 and 34 is made to substantially coincide with the gas flow direction.

[0040] On the introduction port arrangement surface 32 of the third mixing chamber 30, an introduction port for introducing the gas discharged from the discharge ports 24a, 24b of the second mixing chamber 20 into the third mixing chamber 30. 32a and 32b are drilled. In the example shown in the figure, the outlets 24a and 24b of the second mixing chamber 20 and the inlets 32a and 32b of the third mixing chamber 30 are connected by the pipes 40c and 40d in the same manner as described above. Such pipes 40c and 40d may be omitted. The number of outlets of the second mixing chamber 20 and the number of inlets of the third mixing chamber 30 can be made different as described above.

[0041] In the example shown in the figure, the discharge port arrangement surface 34 of the third mixing chamber 30 has a single discharge port 34a. It is preferable that the discharge port 34 is not overlapped with any of the introduction ports 32a and 32b in the gas flow direction. The two inlets 32a and 32b are preferably disposed at substantially equal distances.

[0042] A pipe 40 is connected to the outlet 34 of the third mixing chamber 30 in the gas mixer 1 as described above, and the gas mixed by the gas mixer 1 is connected to the pipe. Guided to 40, it is supplied to a film forming apparatus (not shown) such as a CVD apparatus or a sputtering apparatus (see FIG. 3 described later).

As described above, the gas mixer 1 shown in FIG. 1 is configured to include three mixing chambers 10, 20, and 30. As shown in FIG. Saving the third mixing chamber 30 Variations can be made in an abbreviated manner.

That is, the gas mixer 1 can have two mixing chambers, and the gas mixer 1 has at least two or more mixing chambers.

Here, in the modification of the present embodiment shown in FIG. 2, the third mixing chamber 30 is omitted and the pipes 40e and 40f connected to the discharge ports 24a and 24b of the second mixing chamber 20 are joined. The pipes 40 are grouped together. The gas mixed by the gas mixer 1 is guided to the pipe 40 and supplied to the film forming apparatus.

[0045] Although not shown in the drawings, in this modified example, one discharge port may be provided in the discharge port disposition surface 24 of the second mixing chamber 20. In this case, like the third mixing chamber 30 in the example shown in FIG. 1, this discharge port is disposed at a position that is approximately equidistant from each of the introduction ports formed in the introduction port arrangement surface 22. Is preferred.

[0046] Since the configuration other than the above is the same as the example shown in FIG. 1, detailed description of the other configuration of the example shown in FIG. 2 is omitted.

[0047] The phenomenon in which two or more kinds of gases introduced into the gas mixer 1 of the present embodiment are mixed is, at least, a process in which the gases collide with each other to form a single flow) and a single flow process. This can be explained as having a process in which the gas diffuses and mixes in the flow (diffusion process).

When the pressure is high, the turbulence process is relatively dominant, and when the pressure is low, the diffusion process is relatively dominant.

[0048] In the gas mixer 1 of the present embodiment, the first mixing chamber 10 located on the most upstream side of the gas flow is introduced from the inlets 12a, 12b, 12c, 12d, respectively. It has the function of colliding two or more independent gas flows into a single flow. In the first mixing chamber 10, the introduced gas is mixed mainly by the turbulent flow process. The gas flow mixed in the first mixing chamber 10 is discharged from the discharge ports 14a and 14b.

[0049] At this time, if the gas force introduced from the inlets 12a, 12b, 12c, 12d is discharged from the outlets 14a, 14b with insufficient mixing in the first mixing chamber 10, the first The mixing efficiency in the mixing chamber 10 is reduced. In order to avoid such a problem, in this embodiment, as described above, the inlet and the outlet are not overlapped in the gas flow direction. I have to.

By arranging the outlets 14a, 14b relative to the inlets 12a, 12b, 12c, 12d in this way, the mixing efficiency of the gas introduced into the first mixing chamber 10 can be increased, and the gas can be more evenly and more uniformly. Can be mixed.

[0050] The gas flow discharged from the discharge ports 14a and 14b of the first mixing chamber 10 is introduced into the second mixing chamber 20 that communicates with the discharge ports 14a and 14b via the pipes 40a and 40b (or directly). It is introduced into the second mixing chamber 20 through the ports 22a and 22b.

[0051] The gas introduced into the second mixing chamber 20 is mainly mixed by a diffusion process. At this time, in order to efficiently cause the diffusion of the gas, the pressure in the second mixing chamber 20 is It is preferable to use the gas mixer 1 in a state where it is lower than the pressure in the first mixing chamber 10. As a result, when the gas discharged from the first mixing chamber 10 is introduced into the second mixing chamber 20, an adiabatic expansion effect can be obtained, and mixing by the diffusion process can be effectively generated. It becomes possible.

In order to make the pressure in the second mixing chamber 20 lower than the pressure in the first mixing chamber 10 and efficiently cause gas diffusion in the second mixing chamber 20, the second mixing chamber 20 It is effective to make the volume of 20 larger (preferably twice or more) than the volume of the first mixing chamber 10. As a result, the second mixing chamber 20 located on the downstream side of the gas flow (the film forming apparatus side) can be in a reduced pressure state as compared with the first mixing chamber 10.

[0053] In order to keep the pressure in the second mixing chamber 20 lower than the pressure in the first mixing chamber 10, the total area of the discharge ports 14a, 14b of the first mixing chamber 10 is made as small as possible, The amount of gas flowing into the second mixing chamber 20 can be reduced by reducing the amount of gas discharged from the first mixing chamber 10 or by reducing the total area of the inlets 22a and 22b of the second mixing chamber 20 as much as possible. It is also effective to suppress it. In this case, both the discharge ports 14a and 14b of the first mixing chamber 10 and the introduction ports 22a and 22b of the second mixing chamber 20 are more preferable than the force that makes the total area as small as possible.

Specifically, the total area of the outlets 14a, 14b of the first mixing chamber 10 and / or the inlets 22a, 22b of the second mixing chamber 20 is the total of the respective installation surfaces 14, 22. The area is preferably 1/5 or less, more preferably 1/10 or less, and particularly preferably 1Z30 or less. [0054] The gas mixed in the second mixing chamber 20 is discharged from the discharge ports 24a, 24b. Similarly to the first mixing chamber 10, here, the introduction ports 22a, 22b and the discharge ports 24a, 24b Are preferably arranged so as to overlap each other in the gas flow direction to improve the mixing efficiency of the gas introduced into the second mixing chamber 20.

[0055] The gas flow discharged from the outlets 24a and 24b of the second mixing chamber 20 is introduced into the third mixing chamber 30 that communicates with the outlets 24a and 24b via the pipes 40c and 40d (or directly). It is introduced into the third mixing chamber 30 through the ports 32a and 32b.

[0056] As described above, in the present embodiment, the gas mixer 1 may have at least two or more mixing chambers, but can be applied to various gas types and various film forming conditions. In order to do this, it is preferable to have three mixing chambers 10, 20, 30. In this way, the gas mixed in the first mixing chamber 10 and the second mixing chamber 20 can be mixed more uniformly and uniformly in the third mixing chamber 30.

Here, “various gas species” means that two or more gases to be mixed are gas species whose characteristics such as molecular weight, molecular size, molecular structure, molecular energy potential, and electrical polarity are greatly different. Means. Examples of “various film formation conditions” include the case where the flow rates of two or more gases to be mixed differ greatly, or the two or more gases to be mixed have similar characteristics. This also means when the gas flow rate needs to be changed during the process, or when the gas type to be supplied is switched at an arbitrary time.

[0057] The number of mixing chambers provided in the gas mixer 1 is not limited to three, and may be four or more. However, even if four or more mixing chambers are provided, the mixing chamber may be provided with three mixing chambers. Compared to the complicated structure, it is difficult to recognize a significant difference in effect. For this reason, in terms of balance, the number of mixing chambers is most preferably three.

In the mixer 1 in the present embodiment as described above, when two or more kinds of gases are mixed and supplied to the film forming apparatus, the influence due to the change in the environmental temperature is avoided in the gas mixing process. For this purpose, for example, it is preferable to provide a temperature adjustment mechanism that can adjust the temperature of the entire gas mixer 1 by covering the periphery of the gas mixer 1 with a heater. As a result, a stable mixing state can be ensured regardless of the temperature change of the outside air, and such an embodiment is particularly effective when the gas to be mixed contains a low boiling point. [0059] Further, the piping for introducing the gas into each mixing chamber may be connected obliquely to the introduction surface of each mixing chamber. This also makes it possible to appropriately adjust the direction in which the gas is introduced into each mixing chamber. Such an embodiment is particularly suitable when a high-density gas is introduced into the mixing chamber under high-pressure conditions. It is valid.

[0060] [Film Forming Apparatus]

Next, an embodiment of a film forming apparatus according to the present invention will be described. Here, FIG. 3 is an explanatory diagram showing an outline of the film forming apparatus in the present embodiment. FIG. 4 is a cross-sectional view taken along the line AA in FIG.

A film forming apparatus 100 shown in FIG. 3 and FIG. 4 is an example of a so-called cold wall type decompression CVD apparatus, and a substrate (film formation substrate) 150 disposed on a support means 120 is heated by a hand. The stage 130 is heated to an appropriate temperature, the exhaust pipe 140 exhausts the film formation chamber 110, and an appropriate gas is supplied from the nozzle 42 of the gas supply pipe (pipe) 40 to enter the film formation chamber 110. A thin film is grown on the substrate 150 by forming an appropriate vapor phase.

[0062] In the illustrated example, the gas supply pipe 40 is provided in the film formation chamber 110 in a state where the tip nozzle 42 is erected substantially vertically so that the tip nozzle 42 is located in the center of the film formation chamber 110. The Further, in the film forming chamber 110, a supporting means 120 for supporting the substrate 150 is provided, and a heating means 130 is provided at a position for heating the substrate 150 disposed on the supporting means 120 from the back side. ing. Further, an exhaust pipe 140 is connected to the film forming chamber 110, and this exhaust pipe 140 is connected to an exhaust pump (not shown) through a pressure adjusting valve 145, thereby forming the film forming chamber 110. The inside can be exhausted.

The film forming apparatus 100 in the present embodiment includes the gas mixer 1 as described above, and is connected to the gas mixer 1 outside the gas supply side force film forming chamber 110 of the gas supply pipe 40. Yes. A predetermined gas supply source (for example, a gas cylinder) is connected to the gas mixer 1, and the gas introduced from the gas supply source into the gas mixer 1 is uniformly mixed by the gas mixer 1. To the film forming apparatus 100.

Here, in the illustrated example, the gas mixer 1 is connected to pipes 41a, 41b, 41c, 41d. Pipe 41a is H gas supply source, pipe 41b is N gas supply source, pipe 41c is Si

twenty two

HC1 gas supply source and piping 41d are connected to CH gas supply source.

2 2 2 2

[0064] [Thin Film Manufacturing Method]

Next, regarding the embodiment of the thin film manufacturing method according to the present invention, in the film forming apparatus shown in FIG. 3, a mixed gas containing a silicon source gas and a carbon source gas is supplied and carbonized on the single crystal silicon substrate. An example of forming a silicon film will be described.

In the present embodiment, first, an H gas supply source, an N gas supply source, an SiH C1 gas supply

2 2 2 2 Sources from the C H gas supply source, each gas separately at a predetermined flow rate, into the gas mixer 1

twenty two

Introduce. These gases introduced into the gas mixer 1 are uniformly mixed by passing through the respective mixing chambers of the gas mixer 1 and are discharged from the gas mixer 1.

[0066] Next, the mixed gas discharged from the gas mixer 1 is guided to the gas supply pipe 40 and supplied into the film forming chamber 110 provided in the film forming apparatus 100. At this time, the pressure adjusting valve is used. The film forming chamber 110 is evacuated through the exhaust pipe 140 to maintain the pressure in the film forming chamber 110 at a predetermined pressure, and is disposed on the supporting means 120 by the heating means 130. The formed silicon substrate 150 is heated to a predetermined temperature.

[0067] By maintaining the supply of the mixed gas for a predetermined time while maintaining this state, a silicon carbide thin film to which the dopant (N) is added is formed on the silicon substrate 150 with a predetermined film thickness. . The silicon carbide thin film thus formed has excellent uniformity in film thickness and film quality, reflecting that the mixed gas supplied into the film formation chamber 110 is uniformly mixed. .

[0068] When forming a silicon carbide film on silicon substrate 150, as a pretreatment, the surface layer of silicon substrate 150 may be carbonized in advance, and a thin silicon carbide layer may be formed as a noffer layer. By performing such pretreatment, it is possible to grow a silicon carbide layer having good crystallinity on the silicon substrate 150.

Example

[0069] Next, the present invention will be described in more detail with specific examples.

[Example 1]

Using the deposition apparatus 100 shown in Fig. 3, the crystal plane indicated by the Miller index {001} A silicon carbide film was formed as follows on single crystal silicon substrate 150 having a diameter of 200 mm.

[0070] First, as a pretreatment, the inside of the film forming chamber 110 is exhausted through an exhaust pipe 140, and H gas 20sc.

2 cm, CH gas 50 sccm, through gas mixer 1 and gas supply pipe 40, deposition chamber 11

twenty two

Feeded into 0. At this time, the pressure in the film formation chamber 110 was kept at lOOmTorr, and the temperature of the substrate 150 was heated to 1200 ° C. in about 1 minute by the heating unit 130.

As a result, the surface layer of the silicon substrate 150 is carbonized to form a thin silicon carbide layer as a buffer layer between the silicon substrate 150 and the silicon carbide layer grown on the silicon substrate 150. Thus, a silicon carbide layer having good crystallinity can be grown.

[0071] After performing such pretreatment, while maintaining the substrate temperature, H gas 150sccm, N gas

twenty two

100 sccm, SiH CI gas 200 sccm, CH gas 50 sccm are introduced into the gas mixer 1

2 2 2 2

The mixed gas mixed by the gas mixer 1 was guided by the gas supply pipe 40 and supplied to the film forming chamber 110.

In this manner, a 300 / im silicon carbide thin film doped with dopant (N) was formed on the silicon substrate 150.

Here, in the film forming apparatus 100 shown in FIG. 3, the gas mixer 1 connected to the gas supply side of the gas supply pipe 40 has pipes 40a, 40b, and 40c40d from the embodiment shown in FIG. Omitted, outlets 14a and 14b of first mixing chamber 10 and inlets 22a and 22b of second mixing chamber 20, outlets 24a and 24b of second mixing chamber 20 and inlet 32a of third mixing chamber 30 32b was used in direct communication with each other.

The gas mixer 1 also has a height of the first mixing chamber 10 (length along the gas flow direction) HI of 20 mm, a height of the second mixing chamber 20 of H2 of 60 mm, and a height of the third mixing chamber 30 of 30 mm. The H3 was 20 mm, the diameter of each mixing chamber 10, 20, 30 was 80 mm, and the diameter of the inlet and outlet of each mixing chamber 10, 20, 30 was 10 mm.

Furthermore, considering the stable supply of the mixed gas to the film forming apparatus 100 and the use of a gas having a relatively low boiling point (SiH C1), the gas around the gas mixer 1 and the gas in the pipe 40

twenty two

The part from the mixer 1 to the film forming chamber 110 was covered with a heater and adjusted to a set temperature of 100 ° C. [0073] As a result of measuring the in-plane distribution of resistivity of the obtained silicon carbide thin film, the resistivity distribution was about 15%, and it was confirmed that a uniform thin film was formed on a substrate having a diameter of 200 mm. It was.

The measurement was performed by sampling at intervals of 12 mm using a resistivity measuring device manufactured by Kokusai Electric Inc.

[0074] [Comparative Example 1]

A single crystal with a diameter of 200 mm in which the crystal plane indicated by the Miller index {001} appears on the surface in the same manner as in Example 1 except that each gas was directly supplied to the film forming chamber 110 without going through the gas mixer 1. A silicon carbide thin film having a thickness of 300 xm to which a dopant (N) was added was formed on a silicon substrate 150.

Here, FIG. 5 is an explanatory diagram (corresponding to the A_A cross section of FIG. 3) showing the arrangement of the gas supply pipes 45a, 45b, 45c, 45d in the film forming apparatus used in this comparative example.

Gas supply pipes 45a, 45b, 45c, 45d are not shown, H gas supply source, N gas supply

It is connected to 2 2 source, SiH C1 gas supply source and C H gas supply source. Each gas

2 2 2 2

Supply note. Eve 45a, 45b, 45c, 45d nose, nore 46a, 46b, 46c, 46di are open in the horizontal direction (direction parallel to the substrate 150).

[0076] As a result of measuring the in-plane distribution of resistivity of the obtained silicon carbide thin film in the same manner as in Example 1, it was confirmed that the resistivity distribution was about 40%.

This is because the gas is mixed only in the film forming chamber 110, so the mixing is insufficient, and the resulting silicon carbide thin film has a composition that depends on the arrangement of the gas supply pipes 45a, 45b, 45c, and 45d. This is thought to be due to having segregation.

[0077] [Example 2]

Regarding the gas mixer 1 of the embodiment shown in FIG. 1, the gas mixing ratio immediately after being discharged from the gas mixer 1 (cross section of the pipe 40 near the outlet 34a of the third mixing chamber 30) is as in Example 1. Based on the conditions (gas type, gas flow rate, film forming chamber pressure, etc.), it was obtained by simulation.

Here, the simulation was performed by the following method using general-purpose thermal fluid simulation software FLUENT (manufactured by Fluent. Inc., USA). [0078] First, the gas flow path (space of arbitrary shape) in the gas mixer 1 was subdivided with a mesh of tetrahedron or hexahedron (in the case of three-dimensional calculation). As a result, even a gas flow path having a curved shape such as a circular pipe or a bent pipe can be approximately represented as a solid set having a plane.

Next, the governing equations of the flow field at the center of gravity of each mesh, that is, the momentum equation, the mass conservation equation, the heat transfer equation, and the diffusion equation are calculated by the upwind difference method, and the gas velocity distribution, temperature, Distribution and concentration distribution of the target gas were obtained.

At that time, as boundary conditions, the temperature of the gas flow path wall surface (if there is a temperature distribution), the flow rate of each gas introduced into the first mixing chamber 10 (usual unit [sccm], or SI unit [kg / s ec]) and pressure values at temperature, outlet 34a or pressure reference point (usually the position where pressure is measured). In addition, viscosity coefficient, specific heat, heat conduction coefficient, and diffusion coefficient are given as thermophysical values for each gas, and if there are temperature dependence and pressure dependence for each physical property, they are taken into account.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction was 0.001% or less.

twenty two

The numerical values below the soot detection limit were obtained, and the result showed that gas mixer 1 achieved almost completely uniform gas mixing. Thereby, it was confirmed that the result of Example 1 was reproduced well.

The gas concentration distribution is calculated as the value (percentage) obtained by dividing the difference between the maximum concentration and the minimum concentration of the target gas (SiH C1 gas in this example) in the vertical cross section in the flow direction by the average concentration.

twenty two

did. Table 1 shows the gas concentration distribution of the target gas in Examples 2 to 6 and Comparative Examples 2 to 5.

[0080] [Example 3]

The gas mixing ratio immediately after being discharged from the gas mixer 1 was determined in the same manner as in Example 2 except that the flow rate of each gas introduced into the first mixing chamber 10 was doubled.

twenty two

The numerical values below the soot detection limit are shown, and it was confirmed that almost completely uniform gas mixing was achieved even if the flow rate of each gas introduced into the first mixing chamber 10 was different, and there was no flow rate dependency. It was. [0081] [Example 4]

The gas type to be introduced into the first mixing chamber 10 and its flow rate are WF gas 10 sccm, H gas 25

6 2

The mixing ratio of the gas immediately after being discharged from the gas mixer 1 was determined in the same manner as in Example 2 except that Osccm and Ar gas were set to 300 sccm.

As a result, the WF gas concentration distribution in the vertical cross section in the flow direction is about 0.4%.

6

It was confirmed that even when gases with greatly different molecular weights were mixed, a gas with a significantly large molecular weight could be mixed with other gases sufficiently uniformly and had no dependence on the gas system.

[Example 5]

The gas mixing ratio in the cross section of the pipe 40 immediately after the pipes 42e and 42f were combined into the pipe 40 was determined in the same manner as in Example 2 except that the gas mixer 1 having the mode shown in FIG. 2 was used.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction was about 0.02%.

twenty two

In addition, even with only two mixing chambers, it was confirmed that sufficiently uniform gas mixing was achieved.

[0083] [Comparative Example 2]

In both the first mixing chamber 10 and the second mixing chamber 20, the pipes 42e and 42f are provided in the same manner as in Example 5 except that the discharge port is disposed so as to overlap the introduction port in the gas flow direction. The gas mixing ratio in the cross section of the pipe 40 immediately after being integrated into the pipe 40 was obtained.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction was about 0.643%.

twenty two

As a result, it was confirmed that gas mixing was insufficient as compared with Example 5.

[0084] [Comparative Example 3]

The type of gas introduced into the first mixing chamber and its flow rate are as follows: WF gas 10sccm, H gas 250s

6 2

Except for ccm and Ar gas of 300 sccm, the gas mixing ratio in the cross section of the pipe 40 immediately after the pipes 42e and 42f were combined into the pipe 40 was determined in the same manner as in Comparative Example 4.

As a result, the WF gas concentration distribution in the vertical cross section in the flow direction is about 26.48%.

6

It was confirmed that the gas concentration distribution becomes extremely non-uniform when gases with greatly different molecular weights are mixed. [0085] [Example 6]

The mixing ratio of the gas immediately after being discharged from the gas mixer 1, in the same manner as in Example 5, except that the second mixing chamber 20 has one discharge port and is disposed at the center of the discharge port disposition surface 24. Asked about.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction was about 0.124%.

twenty two

It was confirmed that sufficiently uniform gas mixing was achieved.

[0086] [Comparative Example 4]

In the embodiment shown in FIG. 2, the second mixing chamber 20 is further omitted from the gas mixer 1 shown in FIG. 2, and in the embodiment shown in FIG. 2, pipes 40e, 4 Of connected to the discharge ports 24a, 24b of the second mixing chamber 20 Example 2 except that the pipes 40a and 40b connected to the outlets 12a and 12b of the first mixing chamber 10 are combined into one as in the case of combining the pipes into one pipe 40. In the same manner, the gas mixing ratio in the cross section immediately after the piping 40a and 40b were combined into one was determined.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction is about 8%.

twenty two

It was confirmed that gas mixing was insufficient with only one mixing chamber.

[0087] [Comparative Example 5]

The second mixing chamber 20 is further omitted from the gas mixer 1 of the embodiment shown in FIG. 2, and only one discharge port is disposed at the center of the discharge port disposition surface 14 of the first mixing chamber 10. Except for connecting a pipe to the outlet, the gas mixing ratio immediately after being discharged from the gas mixer 1 was determined in the same manner as in Example 2.

As a result, the SiH C1 gas concentration distribution in the vertical cross section in the flow direction is about 43%.

twenty two

It was confirmed that gas mixing was extremely insufficient when one outlet was provided in one mixing chamber.

Also, by comparison between Comparative Example 4 and Comparative Example 5, the one with two outlets is introduced into the second mixing chamber 20 rather than the one with one outlet in the first mixing chamber 10. It was confirmed that the gas was mixed more uniformly.

[0088] [Table 1] Force 'First mixing chamber Second mixing chamber Third mixing chamber

Distribution) Number of mixing chambers Overlap * Number of outlets Overlap * Number of outlets Overlap * Number of outlets

2 0. 0000 3 0 2 0 2 0 1 Actual 3 0. 0000 3 0 2 0 2 0 1 Out 4 0. 4000 3 0 2 0 2 0 1 Example 5 0. 0200 2 0 2 0 2

6 0. 1240 2 〇 2 〇 1

2 0. 6430 2 X 2 X 2

Ratio

3 26. 480 2 X 2 X 2

Comparison

4 8..0000 1 〇 2

Example

5 43. 000 1 〇 1

*: In the gas flow direction, those that do not overlap the inlet and outlet are indicated by “◯”, and those that overlap are indicated by “X”.

While the present invention has been described with reference to the preferred embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. Needless to say.

Industrial applicability

The present invention can be widely applied in the technical field of forming a thin film on a predetermined substrate by supplying two or more kinds of gases to various film forming apparatuses.

Claims

The scope of the claims

[1] A gas mixer for mixing two or more gases,

At least a first mixing chamber located upstream in the gas flow direction and a second mixing chamber located downstream;

The first mixing chamber is provided with two or more inlets for introducing two or more gases to be mixed and one or more outlets, respectively.

The second mixing chamber communicates with an exhaust port provided in the first mixing chamber, and includes at least one introduction port into which the gas discharged from the first mixing chamber is introduced, and at least one exhaust port And is provided,

The discharge port provided in the first mixing chamber and / or the second mixing chamber is arranged so as not to overlap with the introduction port provided in the same mixing chamber in the gas flow direction. A gas mixer characterized by that.

[2] The gas mixer according to claim 1, wherein when mixing two or more kinds of gases, the pressure of the second mixing chamber is lower than the pressure of the first mixing chamber. .

[3] The gas mixer according to any one of claims 1 to 2, wherein the volume of the second mixing chamber is larger than the volume of the first mixing chamber.

[4] The total area of the discharge port provided in the first mixing chamber and / or the introduction port provided in the second mixing chamber is 1/5 or less of the area of the respective installation surfaces. Claims characterized in any one of claims 1 to 3 The gas mixer according to item 4.

[5] The second mixing chamber has two or more outlets, and pipes connected to each of the outlets are merged to be combined into one pipe. The gas mixer according to any one of ˜4.

[6] One or more inlets through which the gas discharged from the second mixing chamber is introduced and at least one outlet are provided in communication with the outlet provided in the second mixing chamber. The gas mixer according to any one of claims 1 to 4, further comprising a third mixing chamber.

[7] The gas mixer according to any one of [1] to [6], further comprising a temperature control mechanism.

[8] Two or more kinds of gases are supplied into the film formation chamber, and thin films are formed on the substrate disposed in the film formation chamber. A film forming apparatus for forming a film,

A gas supply pipe for supplying two or more kinds of gases mixed in the film forming chamber;

The gas supply pipe is connected to a gas supply source via a gas mixer;

The gas mixer is

The discharge port provided in the first mixing chamber and / or the second mixing chamber is disposed so as not to overlap with the introduction port provided in the same mixing chamber in the gas flow direction. A characteristic film forming apparatus.

A thin film manufacturing method for forming a thin film on a substrate disposed in the film forming apparatus by supplying two or more gases to the film forming apparatus,

A gas mixer in which the discharge port provided in the first mixing chamber and / or the second mixing chamber is arranged so as not to overlap with the introduction port provided in the same mixing chamber in the gas flow direction. Through

Supply two or more kinds of mixed gases to the film forming device to form a thin film on the substrate A method for producing a thin film, comprising:

10. The thin film manufacturing method according to claim 9, wherein a mixed gas containing at least a silicon source gas and a carbon source gas is supplied to a film forming apparatus to form a silicon carbide film on the substrate.