JP5731301B2 - Gas supply device for vacuum processing equipment - Google Patents

Description

  The present invention relates to a gas supply device for a vacuum processing apparatus, and more particularly to a gas supply apparatus used for introducing a plurality of types of source gases into a reaction chamber under reduced pressure by a MOCVD apparatus.

  Conventionally, for example, as a method for forming an organometallic compound film, it is known to obtain an organometallic compound film by deposition of an organometallic compound from a gas phase (see, for example, Patent Document 1). In general, a MOCVD (metal organic chemical vapor deposition) apparatus as a vacuum processing apparatus is generally used. A gas supply apparatus is used to supply the MOCVD apparatus with source gases made of two or more kinds of organometallic materials selected according to the composition of the organometallic compound film to be formed.

  Here, when forming a film by the MOCVD method, the reactivity is very high depending on the type of the source gas, and if each source gas is mixed before being introduced into the reaction chamber, the reaction is promoted to generate particles and the like. This may be a factor that hinders good film formation. Therefore, as described in Patent Document 1 above, instead of using a mixer that mixes each raw material gas in advance, the raw material gas is introduced to the reaction chamber in which the substrate to be processed is arranged without being mixed. Mixing raw material gases is generally carried out (so-called postmix type gas introduction device).

  FIG. 3 shows an MOCVD apparatus equipped with a so-called postmix type gas supply apparatus. This includes a vacuum chamber 1 that defines a reaction chamber 1a, and a vacuum control valve APC or the like that is connected to a vacuum pump P that evacuates and depressurizes the inside of the reaction chamber 1a. An exhaust pipe 2 is connected. A stage 3 for positioning and holding the substrate W to be processed is provided at the bottom of the vacuum chamber 1. A gas introduction unit 4 of the gas supply device GS facing the reaction chamber 1a is provided on the ceiling of the vacuum chamber 1 so as to face the substrate W.

The case where two kinds of source gases are introduced into the reaction chamber 1a will be described as an example. The gas introduction unit 4 includes three separator plates 4 ₁ to 4 ₃ arranged at equal intervals in the vertical direction, and two sheets facing each other. The lower isolation space 4a and the upper isolation space 4b of the same volume defined by the separation plates 4 ₁ to 4 _{3 respectively} . Diaphragm 4 ₃ The upper also serves as a top plate of the vacuum chamber 1, also the diaphragm 4 _1, 4 ₂ is held by an annular wall 41 which projects towards the reaction chamber 1a to the top plate 4 ₃ ing. Further, the partition plate 4 ₁ of lowermost, a plurality of gas inlet 42a in a predetermined pattern, 42b is opened, the diaphragm 4 ₁ is turned to serve the shower plate. Half of the gas inlets 42a communicate directly with the lower isolation space 4a. On the other hand, the remaining half 42b is provided with a straw tube 43 that constitutes a communication path, and the upper end of the straw tube 43 penetrates the lower isolation space 4a in the vertical direction, and the upper isolation space. Each communicates with 4b. Usually, the inner diameter of the gas inlet 42a and the inner diameter of the straw tube 43 inserted in the other gas inlet 42b are the same, and the total area of the gas inlets 42a and 42b is designed to match each other. .

Gas supply pipes 5 ₁ and 5 ₂ communicating with a gas source (not shown) are connected to both the isolation spaces 4a and 4b. Both gas supply pipes 5 ₁ , 5 ₂ are provided with a mass flow controller (flow rate control means) 51 so that each source gas can be introduced into both isolation spaces 4 a, 4 b at a predetermined flow rate. In this case, in order to dilute the source gas, or to send the source gas to the reaction chamber, etc., the mass flow controller 61 is used to supply a rare gas such as argon or nitrogen to both the gas supply pipes 5 ₁ , 5 _2. The provided inert gas supply pipes 5 ₁ and 5 ₂ may be connected to each other.

Meanwhile, two kinds of the raw material gas into the reaction chamber 1a in the gas supply system GS to each feed, when forming by reacting with the substrate W surface, both gas inlet port 42a of the shower plate 4 _1, discharge from 42b If there is a difference in flow rate of the gas, for example, the shower plate 4 ₁ and the space inhibited smooth flow of the material gas vortex is generated to the substrate in between the the substrate W, the film thickness and film quality of the substrate surface There arises a problem that the film cannot be formed with good uniformity. Here, the gas flow rate discharged from both the gas inlets 42a and 42b is determined by the total area of the gas inlets 42a and 42b and the amount of gas supplied to the isolation spaces 4a and 4b. As described above, the shower plate 4 gas inlet 42a provided in the _1, since it is possible to design such that the total area of the 42b coincide with each other is usually both isolated space 4a, one with each other even amount of gas supplied to 4b I do it.

  However, in the above-described conventional example, it is difficult to make the gas flow rates of the source gases supplied to the isolation space through the gas supply pipes equal to each other, for example, by using an inert gas also for supplying the source gas from the gas source. In many cases, and further, for example, when the set flow rate is deviated due to a failure of the mass flow controller or the like, the gas supply amount to the isolation space changes. In addition, as described above, when a plurality of isolation spaces are provided in a direction away from the substrate, the gas flow rate introduced into the reaction chamber from each isolation space through the gas supply pipe easily changes.

JP 2005-158919 A

  In view of the above points, the present invention is capable of introducing a plurality of types of source gases into a plurality of isolated spaces with the same gas supply amount and supplying the substrate with the same gas flow rate with a simple configuration vacuum processing. An object of the present invention is to provide a gas supply device for an apparatus.

Gas in order to solve the above problems, the present invention is such that mixing a plurality of kinds of raw material gases Ku, a gas supply apparatus for a vacuum processing apparatus which respectively introduced into the reaction chamber under reduced pressure, facing the reaction chamber The gas introduction unit has a plurality of isolated spaces, each of which is connected to a gas supply pipe through which a flow rate control means for supplying a source gas is connected. A gas introduction port leading to each reaction chamber is provided, and each gas supply pipe is connected to a branch pipe branched from one gas pipe provided with other flow rate control means, and the flow rate of gas flowing through this gas pipe Is controlled to be larger than the flow rate difference of the raw material gas flowing through the gas supply pipe, and the total gas flow rate of the raw material gas and the gas from each branch pipe respectively introduced from the respective gas inlets to the reaction chamber is equal. characterized in that set to be.

According to the present invention, since the structure in which the branch pipe branched from one gas pipe is connected to the gas supply pipe for introducing the raw material gas is adopted, two kinds of raw material gases are transferred into the reaction chamber by the two gas supply pipes. In the case of introducing each of the two, the pressures in the two gas supply pipes on the downstream side of the flow rate control means communicating with each other in the reaction chamber under reduced pressure are equal. When the gas flow rate of either one of the gas supply pipes decreases, the inert gas preferentially flows into the reduced gas supply pipe from the branch pipe, thereby supplying the gas to both isolation spaces with a simple configuration. It is possible to realize a configuration in which the gas flow rates introduced through the pipes match each other. In addition, by controlling the gas flow rate in the branch pipe to be larger than the flow rate difference of the raw material gas flowing in the gas supply pipe, the flow rate of the gas discharged from the gas inlet can be made the same, and both gases can be smoothly boarded. In addition, it is possible to reliably suppress the occurrence of problems such as the inert gas flowing backward in the gas supply pipe. In the present invention, the coincidence of the gas flow rates is not limited to the case where the gas flow rates are strictly the same (that is, the total gas flow rate of the raw material gas and the inert gas for flow rate adjustment), This includes the case where the difference between the gas flow rates discharged from the two gas inlets is small, the source gas is smoothly supplied to the substrate, and the film thickness and film quality can be formed with good uniformity within the substrate surface.

  In the present invention, if the lengths of the gas supply pipes from the connection location of the branch pipe to each isolation space are made uniform, a plurality of types of source gases can be more reliably supplied to the substrate at the same flow rate.

  In the present invention, it is preferable that the conductances of the gas inlets that lead from the respective isolation spaces to the reaction chamber are matched. According to this, coupled with the fact that the gas flow rates to the isolation space can be made to coincide with each other, a plurality of types of source gases (that is, source gases and inert gases) can be reliably supplied to the substrate at equal flow rates. Can be supplied to.

  In the present invention, each of the isolation spaces is defined by two opposing diaphragms among a plurality of diaphragms arranged in one direction, and is directed to the reaction chamber in the direction in which each diaphragm is arranged. The gas introduction port is opened in the partition plate located at the lowermost side with the direction facing downward, and these gas introduction ports communicate directly with the isolation space on the lowermost side and move the isolation space or the partition plate up and down. What is necessary is just to make it each communicate with each other isolation space via the communicating path which penetrates in a direction.

The figure which shows typically the MOCVD apparatus provided with the gas supply apparatus of embodiment of this invention. The top view of the partition plate which is a shower plate. The figure which shows typically the MOCVD apparatus provided with the gas supply apparatus of the prior art example.

  In the following, referring to the drawings, the vacuum processing apparatus is an MOCVD apparatus, and raw material gases from both containers in which two kinds of raw materials are stored in a liquid phase state are put into a reaction chamber through two gas supply pipes in a post-mix type. Taking the case of introduction as an example, a gas supply apparatus for a vacuum processing apparatus according to an embodiment of the present invention will be described. In the following, the same symbols are used for the same members and elements as in the conventional example.

Referring to FIG. 1, a gas supply device GS includes a gas introduction pipe 4 provided at the ceiling of a reaction chamber, and a gas supply pipe provided with a mass flow controller 51 (flow rate control means) for supplying both source gases. 5 ₁ , 5 ₂ and a gas source (not shown) that feeds the source gas to the gas supply pipes 5 ₁ , 5 ₂ . As the gas source, a known gas source can be used, and although not particularly illustrated and described, for example, a container for storing each raw material in a liquid phase state is provided. The raw material is selected according to the composition of the organometallic compound film to be formed on the surface of the substrate W. For example, when a predetermined organometallic compound film is formed in the manufacturing process of the light emitting diode, In, Ga, N ₂ Mg is used. In this case, the same kind of raw material can be stored in a plurality of containers.

Each container is provided with a heater (not shown) so that the raw material is heated and held at a predetermined temperature corresponding to its vapor pressure. Each container is connected to a pushing gas line for supplying a pushing gas (bubbling gas) made of an inert gas. Then, the flow rate controlled Pusshingugasu is introduced into the container, by bubbling action of the Pusshingugasu, raw material gas is fed to the first and both the gas supply pipe 5 _{1 second,} 5 _2.

Incidentally, both isolated space 4a through the gas supply pipe 5 _1, 5 _2, introduced respectively gas (i.e., the raw material gas and inert gas) to 4b, both isolated space 4a, once spread gas 4b shower both gas inlet 42a of the plate _{4 1,} the raw material gas was respectively supplied from 42b into the reaction chamber 1a, when forming by reacting with the substrate W surface, both gas inlet port 42a of the shower plate _{4 1,} discharge from 42b If there is a difference in gas flow rate (flow velocity) which is, for example, vortex in a space between the shower plate 4 ₁ and the substrate W is inhibited smooth flow of the raw material gas to the substrate W is generated, the film thickness and film quality The film cannot be formed with good uniformity in the substrate surface. In the present embodiment, gas supply pipes 5 ₁ , 5 ₂ having the same diameter are used as gas supply pipes 5 ₁ , 5 _{2 in} order to match the gas supply amounts of the source gases to the both isolation spaces 4 a, 4 b, and from the mass flow controller 51 to the both isolation spaces. The lengths up to 4a and 4b were the same.

Further, as described above, separately from the inert gas supply pipes 6 ₁ and 6 ₂ for diluting the source gas or sending the source gas to the reaction chamber 1a (not shown in FIG. 1), Branch pipes 7 ₁ , 7 branched from one gas pipe 7 provided with a mass flow controller 71 (other flow rate control means) for introducing an inert gas such as argon into each gas supply pipe 5 ₁ , 5 _{2. 2} was respectively connected, when supplying the raw material gas through a gas supply pipe ₅ 1, _{5 2,} the flow rate adjustment from the branch pipe _{71, 7 2} in the gas supply pipe ₅ 1, _{5 2} downstream of the mass flow controller 51 It was decided to flow an inert gas. In this case, the lengths of both the branch pipes 7 ₁ and 7 ₂ are made uniform, and the flow rate of the gas flowing through the gas pipe 7 is controlled to be larger than the flow rate difference of the source gas flowing through the gas supply pipes 5 ₁ and 5 _2. It was decided. The flow rate control may be performed, for example, by controlling the mass flow controller 71 by a control unit that performs overall control of the operation of the MOCVD apparatus.

According to the above, the pressures in the gas supply pipes 5 ₁ and 5 ₂ on the downstream side of the mass flow controller 51 communicating with the reaction chamber 1a under reduced pressure are equal. When the gas flow rate of either _{one of} the gas supply pipes 5 ₁ and 5 ₂ is reduced, the inert gas is preferentially supplied from the branch pipes 7 ₁ and 7 ₂ to the reduced gas supply pipes 5 ₁ and 5 _2. By flowing in, the gas flow rates (total gas flow rates of the raw material gas and the inert gas) introduced into the both isolation spaces 4a and 4b via the gas supply pipes 5 ₁ and 5 ₂ are made to coincide with each other with a simple configuration. Configuration can be realized. Further, the flow rate of the inert gas, by controlling so much made of the flow rate difference of the raw material gas flowing through the gas supply pipe 5 _1, 5 _2, gas inlets 42a, the flow rate of the gas discharged from 42b in the same it can be both gas can be smoothly supplied to the substrate, moreover, it is possible to reliably suppress the occurrence of problems such as an inert gas to flow back through the gas supply pipe 5 _1, 5 _2.

Next, in order to discharge the raw material gas at the same flow rate into the reaction chamber 1a from the both isolation spaces 4a and 4b through the gas inlets 42a and 42b, as shown in FIG. together match the formation number of a gas inlet 42b, formed at equal intervals in the shower plate 4 ₁ so as to alternately. Then, the inner diameter of the straw tube 43 whose tip is inserted into the gas introduction port 42b is made smaller than that of the gas introduction port 42a (the inner diameter is made different), and is communicated from the lower isolation space 4a to the reaction chamber 1a. The conductances of the gas inlet 42a and the other gas inlet 42b communicating with the reaction chamber 1a from the upper isolation space 4b through the straw tube 43 are made to coincide with each other. In this case, in the pressure range in the reaction chamber 1a at the time of film formation by MOCVD (the pressures in the isolation spaces 4a and 4b are equal), usually a viscous flow region is obtained. calculates the conductance of each of the length of the length of the gas inlet 42a (diaphragm 4 ₁ of thickness) and straw tube 43, may be determined diameter in consideration of the conductance.

According to the above, until the gas is discharged from the lower isolation space 4a directly to the reaction chamber 1a via the gas inlet 42a, the end portion (that is, the gas supply port) passes from the upper isolation space 4b through the straw tube 43. 42b) to the discharge until the reaction chamber 1a is discharged, and the gas flow rates to the two isolation spaces 4a and 4b can be made to coincide with each other. A gas composed of a gas and an inert gas can be reliably supplied at an equivalent flow rate.

  As mentioned above, although embodiment of this invention was described, this invention is not limited above. In the above embodiment, the case where two types of source gases are supplied into the reaction chamber has been described as an example, but the gas supply apparatus of the present invention can also be applied to supply three or more types of source gases. In the above-described embodiment, the MOCVD apparatus is taken as an example of the processing apparatus. However, the processing apparatus is not limited to this, and may supply and mix plural kinds of source gases to the substrate in the reaction chamber. For example, the gas supply system of the present invention can be widely applied.

In the above-described embodiment, the three partition plates 4 ₁ to 4 ₃ are arranged at equal intervals in the vertical direction, and the two isolated plates 4 ₁ to 4 ₃ facing each other form a lower isolation space 4a having the same volume. However, as long as a plurality of isolation spaces are formed, the form of the gas introduction part is not limited to the above. For example, by using a plurality of plate materials having the same contour and having a predetermined thickness, concave portions that constitute gas passages and the like are formed on the upper surface and lower surface of each plate material, and these are overlapped and joined in the vertical direction. The gas introduction part can be configured by forming an isolated space that is isolated from each other, and through each of the isolated spaces, a gas introduction port that penetrates the plate material in the vertical direction and communicates with the lowermost plate material.

Further, in the present embodiment, the flow rate control unit is configured by the mass flow controller. However, the present invention is not limited to this. Furthermore, in the above-described embodiment, an example has been described in which the diameter of the gas inlet is made different in order to make conductance uniform. However, the present invention is not limited to this, and other methods may be used. In the above embodiment, when supplying the raw material gas through a gas supply pipe ₅ 1, _{5 2,} the flow from the branch pipe _{71, 7 2} downstream in the gas supply pipe ₅ 1, _{5 2} of the mass flow controller 51 Although the inert gas for adjustment is made to flow, the present invention is not limited to this, and in some cases, the raw material gas can also be used for flow rate adjustment.

DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber (Vacuum processing apparatus (MOCVD apparatus), GS ... Gas supply apparatus, 4 ... Gas introduction part, 4 < ₁ >, 4 < ₂ >, 4 < ₃ > ... Separation plate, 4a, 4b ... Isolation space, 42a, 42b ... Gas introduction Mouth, 43 ... Straw pipe (communication path), 5 ₁ , 5 ₂ ... Gas supply pipe (for source gas), 51, 71 ... Mass flow controller (flow rate control means), 7 ... Gas pipe (inert for flow rate adjustment) For gas), 7 ₁ , 7 ₂ ...

Claims (4)

Things Ku mixing a plurality of kinds of raw material gas, a gas supply apparatus for a vacuum processing apparatus which respectively introduced into the reaction chamber under reduced pressure,
A gas introduction part facing the reaction chamber is provided, and the gas introduction part has a plurality of isolated spaces, and gas supply pipes for supplying a raw material gas are connected to each isolated space via a flow rate control unit, respectively. , Gas inlets are provided from each isolated space to the reaction chamber,
Each gas supply pipe is connected to a branch pipe branched from one gas pipe provided with other flow rate control means, and the flow rate of the gas flowing through this gas pipe is determined by the flow rate difference of the raw material gas flowing through the gas supply pipe. The vacuum processing is characterized in that the total gas flow rate of the raw material gas and the gas from each branch pipe, which are controlled so as to be increased, are introduced into the reaction chamber from each gas introduction port , respectively, are equal. Gas supply device for equipment.
  2. The gas supply apparatus for a vacuum processing apparatus according to claim 1, wherein the length of the gas supply pipe from the connection location of the branch pipe to each isolation space is made uniform.   The gas supply device for a vacuum processing apparatus according to claim 1 or 2, wherein conductances of gas introduction ports respectively communicating from the respective isolation spaces to the reaction chamber are made to coincide with each other.   Each of the isolation spaces is defined by two opposing diaphragms among a plurality of diaphragms arranged in one direction, with the direction toward the reaction chamber being the bottom in the direction of arrangement of each diaphragm, and the lowest The gas introduction ports are opened in the partition plate located on the side, and these gas introduction ports communicate directly with the lowest isolation space and communicate with the isolation space or the communication passage that vertically penetrates the separation plate. The gas supply device for a vacuum processing apparatus according to any one of claims 1 to 3, wherein the gas supply device communicates with each other isolation space via a gas passage.

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