JPH06275544A - Semiconductor working device - Google Patents

Abstract

PURPOSE:To improve the flow rate controlling characteristic of a gaseous starting material supplying device by simplifying the constitution of the device. CONSTITUTION:A flow rate valve 42 is connected to the exit side of a bubbler 41 and hydrogen saturated with an organic metal is passed through the valve 42. The section from the exit of the bubbler 41 to the connecting section of a pipeline to a reaction furnace through the valve 42 is housed in a thermostat 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a semiconductor processing apparatus including at least a metal-organic vapor phase epitaxy chamber and a source gas supply device for the chamber.

[0002]

2. Description of the Related Art Metalorganic vapor phase epitaxy (hereinafter MOCV
D) is often used for ultrathin film growth of compound semiconductors along with molecular beam epitaxy (MBE).
It has a growth rate higher than that of BE and can be easily controlled in composition. Therefore, it is widely used in industrial mass production equipment and for growing quaternary thin films. However, such MOCV
The conventional semiconductor processing apparatus including the D growth chamber still has various points to be improved. One of them is a problem in the apparatus for supplying the source gas to the reaction furnace in the MOCVD growth chamber. Therefore, in order to clarify this point, a piping system of a conventional raw material gas supply device is shown in FIG. 8 and explained.

In the conventional raw material gas supply apparatus 10 shown in FIG. 8, the element indicated by reference symbol AV is a flow passage opening / closing valve generally constituted by a pneumatic valve, and the element indicated by reference symbol MFC. Is a mass flow controller, that is, a flow rate adjusting valve. These are controlled according to a predetermined program, and recently, according to a predetermined program by an electronic control system including a microcomputer or a personal computer. On the other hand, the element indicated by reference numeral MV is a manual valve.

In the case of the drawing, the piping system 11 in the apparatus is shown only for one system surrounded by a frame of imaginary line, but in reality, a piping system of the same configuration as the drawing is provided in the same apparatus housing. Multiple,
They are provided in parallel with each other. Here, the piping system 11 for only one system shown in the figure is used as a representative, and its operation will be briefly described. Pure hydrogen for bubbling supplied from the pure hydrogen input port is introduced to the bubbler 15 via the valve 14 while being adjusted to a predetermined flow rate by the flow rate adjusting valve 13 via the open valve 12, and is stored therein. Bubbling the liquid metal material.

As a result, the raw material gas saturated with the organic metal is released through the valve 16, but at the time of bubbling, the valve 21 and the valve are closed.
Since 25 is closed and valves 17 and 19 are open, the source gas is
Manual orifice or variable conductance valve from 17
The gas is introduced into a gas supply line 20 via a valve 18 and a valve 19, and is introduced into a MOCVD growth chamber (not shown) by a pipe external to the apparatus. However, even if bubbling occurs, MOCVD
In the state where the raw material gas supply to the growth chamber is on standby (that is, in the idling state), the valve 19 is closed, the valve 25 is opened, and the raw material gas is flown into the exhaust line 26 through the valve 25. Be done.

Another flow rate adjusting valve 23, which is provided in parallel with the flow rate adjusting valve 13 provided in the main passage of pure hydrogen for bubbling, is for supplying balanced hydrogen and is a pressure gauge. It is controlled by a control system not shown in conjunction with 24. In the case of conventional devices, this separate closed-loop pressure control is essential.

In addition, there are valves 21 and 29 that are opened when bubbling is stopped or when vacuum suction is performed as required, and a flow rate adjusting valve that can directly supply pure hydrogen to the gas supply line 20 and the exhaust line 26. 27 and 28 are also provided.

[0008]

As is apparent from FIG. 8, in the conventional raw material gas supply device, the number of parts required for each system of the piping system 11 is considerably large. As described above, in practice, a plurality of systems of the same type of piping system are provided (7 systems, 8 systems, etc. are common), and as a whole, the number is considerably increased. In particular, the pressure gauge 24 (indicated by PG in the drawing), the flow rate adjusting valve 23 controlled in conjunction with the pressure gauge 24, the manual orifice 18 and the like must be provided for each system one by one. The flow control valves 27 and 28, which are directly connected to the gas supply line 20 and the exhaust line 26, can be commonly used in all the systems.

Further, this conventional device is characterized in that the flow rate adjusting valve 13 is placed upstream (inlet side) of the bubbler and is not provided downstream (outlet side). This is because when hydrogen gas saturated with metal passes through the flow rate adjusting valve, it is considered that the organic metal aggregates as a result of adiabatic expansion in the throttled portion. In other words, it can be said that it was not possible to escape from a complicated structure because such an idea was followed, and it was difficult to precisely control the flow rate of the feed material gas, and further, to precisely control the composition.

In addition to the problems related to such a piping system and the raw material gas supply device, the MO provided so far is provided.
There are various problems in the CVD growth apparatus. For example, MBE
Since ultra-high vacuum and low emission gas characteristics are not required to such an extent, such characteristics tend to be insufficient.In addition, the polycrystal adhering to the upper part of the inner wall of the reactor in the growth chamber falls onto the substrate surface and crystallizes. There was an inconvenience such as generation of defects. In order to prevent this, the inside of the furnace must be cleaned frequently, maintainability,
It was inferior in productivity.

In addition, it may be highly desirable in terms of device production that the semiconductor to be processed on which a thin film has been grown by MOCVD is immediately etched thereafter without being exposed to the atmosphere. I couldn't handle this.

[0012]

In order to solve or reduce the above-mentioned various problems in order, in the present invention, first, a flow rate adjusting valve for adjusting the flow rate of hydrogen saturated with an organic metal is provided on the outlet side of a bubbler. However, since the problem of adiabatic expansion mentioned above may occur as it is, including the bubbler and the flow rate adjusting valve,
A piping system from the inlet of pure hydrogen to the outlet of the source gas supply line to the MOCVD growth chamber is housed in a thermostatic chamber.

Further, according to the present invention, in addition to satisfying the above-mentioned basic structure, the flow rate adjusting valves provided on the outlet side of the bubbler are selectively used in a parallel relationship with each other, or a plurality of them can be simultaneously used. Also suggest.

In another aspect of the present invention, the substrate holder is generally placed in a reaction furnace of an MOCVD growth chamber composed of an outer tube and an inner tube, and the substrate holder is used to hold the substrate. We also propose a structure in which the crystal growth surface of is arranged downward.

In yet another aspect of the invention, the MO
An apparatus is also proposed in which an etching chamber is provided adjacent to the CVD growth chamber so that substrates can be transferred without breaking vacuum. This etching chamber is preferably an ECR etching chamber, but it may be a parallel plate type. In the latter case, according to another aspect of the present invention, the MOCVD reaction tube itself is provided with a high frequency electrode structure for plasma generation by parallel plate electrodes in the reaction furnace itself of the MOCVD growth chamber. A configuration to be used as is also proposed. This is achieved by providing a pair of parallel plate electrodes so as to sandwich the substrate held by the inner tube of the reaction tube.

In this regard, in a particular embodiment of the present invention, the material of the reaction tube (generally quartz) is utilized as a dielectric between the terminals of the capacitor, and the first metal surrounds the outer wall of the outer tube of the reaction tube. The plate is formed as a first capacitor terminal conductor, and a second metal plate is formed as a second capacitor terminal conductor around the inner wall of the reaction tube outer tube at a position facing inward in the radial direction. A tongue-shaped conductor portion extending from the second terminal conductor is provided and brought into contact with the substrate holder of the reaction tube inner tube, while a third metal plate is provided on the inner wall of the reaction tube inner tube at a portion facing the substrate. We also propose a configuration. As a result, when high frequency power is applied between the first metal plate and the third metal plate forming the first capacitor terminal conductor, the parallel plate type plasma generation mechanism including the matching capacitor is MOCVD-processed. Can be incorporated into the reactor itself.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a main part of an internal structure of a raw material gas supply device 30 for supplying a raw material gas to a MOCVD growth chamber in a semiconductor processing apparatus constructed according to the present invention. In FIG. 2, a cross section of a main part is shown in order to show a concrete example of the positional relationship of each element. Hereinafter, the description will be started according to these drawings, but as already mentioned,
The source gas supply system each having a bubbler 41 is often three or more, and more often a plurality of source gas supply systems. In fact, the source gas supply apparatus 30 configured according to the present invention has such a simple system. Therefore, FIG. 1 shows only two source gas supply systems, and FIG. 2 shows only one of them. Further, regarding these two raw material gas supply systems, the same elements or components are designated by the same reference numerals, and therefore the functions of the respective components or components described below are the same as those of these two gas supply systems. It is the same in each. However, in the gas supply system shown on the lower side, as will be described later, two flow rate adjusting valves (42, 4) are connected to the outlet side of the bubbler 41.
2 ') It differs from the one shown above in some respects.

One of the features of the present invention shown in this embodiment is that a flow rate adjusting valve (MFC) 42 is provided on the outlet side of the bubbler 41 to bubble the liquid organic metal in the bubbler 41. Thus, the flow rate of the hydrogen gas saturated with the organic metal is adjusted by the flow rate adjusting valve 42. That is, pure hydrogen supplied from a pure hydrogen source (not shown) to the pure hydrogen input port of this device passes through the input side flow rate adjusting valve 32 common to all systems and the hydrogen supply line 33 common to all systems. However, unlike the case where the flow rate is supplied to each system in a branched manner and then the flow rate control valve (reference numeral 13 in FIG. 8) dedicated to each system is conventionally supplied to the bubbler, the present invention simply uses the valve 34. , 39 to the bubbler 41. It should be noted that each valve is provided with symbols AV and MV as in the case of FIG. 8 described above, and the valve with the symbol MV is a manual valve. In contrast, although not limiting, the valve labeled AV is generally comprised of a pneumatic valve, which is not, but is not limited to, an electronic control circuit with a conventional configuration. The solenoid valve is selectively controlled according to a predetermined program to selectively open / close as the air supply / exhaust is controlled.

The hydrogen bubbling the liquid organometallic material in the bubbler 41 is supplied to the flow rate adjusting valve 42 through the valves 40 and 36 in order, and after being adjusted to a desired flow rate there, the device is operated via the valve 43. Flow to the gas supply line 45 inside, and then reach the output port of the apparatus through the variable conductance valve 47 common to all systems, and from there, it is sent to the MOCVD growth chamber (not shown) by the external piping member (not shown). Or
Alternatively, in the standby state or the idling state, the gas is exhausted to the outside of the device through the flow rate adjusting valve 42, the valve 44, and the exhaust line 46 in the device including the variable conductance valve 48 common to all systems. Therefore, the above-mentioned valves 43 and 44 determine the destination of the source gas after bubbling, and can be called a manifold valve or a pipe switching valve in combination with both.
In addition, as for these valves, those of each system are generally integrated into an integrated housing device to form a valve unit.

However, if the flow rate adjusting valve 42 is arranged at the bubbler outlet side, the apparatus structure itself is expected to be extremely simple and a great improvement in performance is expected as will be examined later. Since the hydrogen gas passing through is already saturated with the organic metal, if the temperature of the pipe is about the same as that of the bubbler, adiabatic expansion may occur at the throttle in the flow rate control valve 42, and the organic metal may aggregate. Therefore, in the present invention, the entire piping system in the illustrated apparatus is housed in the constant temperature bath 31. Thus, for example, when the bubbling temperature is from -10 ° C to + 30 ° C, the constant temperature bath 31 is heated to 60 ° C, for example.
The bubbling temperature is 20 to 20
If a temperature as high as about 30 ° C. is maintained, such a problem of aggregation can be solved, and as described below, only the advantage of providing the flow rate adjusting valve 42 on the bubbler outlet side can be brought out. . In principle, if the portion from the outlet of the bubbler 41 to the distribution valves 43 and 44 through the flow rate adjusting valve 42 is put in the constant temperature bath 31, the above-mentioned problem of aggregation can be solved, but in practice As shown in the figure, when making the device, it is easier to make almost all of the piping system in the device 30 in the constant temperature bath 31, and the other piping systems can be kept at a constant temperature. Often desirable.

With the above structure, the accuracy of the flow rate adjustment by the flow rate adjusting valve 42 is increased, and in the case of the illustrated embodiment, some further improvements can be made. For example, the hydrogen supply line 33 A single pressure gauge 50 is provided for this common exhaust line 49 in addition to a common exhaust line 49 branching from this supply line 33 for all systems. Feedback control of the flow rate adjusting valve 32 by an electronic control device (not shown) based on
It stabilizes the system pressure. For example, under the experiment according to the present invention, in order to keep the pressure in the common hydrogen supply line 33 at 900 torr and prevent the mixing of the organic metal, the common exhaust line 49
200 to 300 sccm of hydrogen was constantly flown inside. This also helps improve the transient response characteristics of pressure control. For exhausting or evacuating from the common exhaust line 49 via the variable conductance valve 51 or the valve 37 around the bubbler 41, a common exhaust pipe 52 in the apparatus is connected to a vacuum suction device (not shown) by a known connection. It is done by connecting by the method.

Although not specifically shown in the control circuit system, the pressure before and after the bubbler is monitored, and when the hydrogen supply pressure falls below 1 atm or the pressure at the bubbler outlet exceeds the supply pressure. Made a program to close the valves 34 and 36 before and after the bubbler to prevent the backflow of the organic metal due to an erroneous operation. Further, the valves 34, 35, 36, 37, which are valves around the bubbler 41 and which are selectively opened and closed at the time of bubbling, idling, exhausting, etc., are combined into a single body as a composite valve unit 38 in a compact body, The retention of raw material gas was suppressed.

From the above, as is apparent from comparison with the conventional source gas supply apparatus 10 shown in FIG. 8, individual pressure gauges 24 required for each system and feedback based on this are provided. The individual flow rate control valve 23 to be controlled, the individual manual orifice 18 and the like are not necessary in the present invention, so that one common to all systems can be saved and the number of parts can be considerably reduced. Practically, as the number of systems increases, as in the case where seven or eight systems are provided in one device as described above, the component saving effect of the present invention is considerably large. Further, in the case of the present invention, since the entire pipe is always in a baking state, the amount of organic metal remaining is small, which is extremely advantageous in terms of maintenance. Is connected to the flow control valve 42.
Because of the small gas capacity at the end, the flow rate control is excellent in high-speed response.

Further, as shown in the lower system in FIG. 1, a plurality of outputs from the bubbler 41 (two in the case shown) are provided.
The configuration given to the flow rate adjusting valves 42, 42 'of (1) is quite effective in practical semiconductor processing for device construction. For example, in an optoelectronic device, it is necessary to combine AlGaAs layers having different aluminum compositions to produce quantum wells having different emission wavelengths, or to form a thin film laminated structure in which the composition is continuously changed.
In such a case, generally, in MOCVD, the raw material gas at a flow rate required in the next step is made to flow to the exhaust line in the idling mode in advance, and when it becomes necessary, the distribution switching valve is rapidly switched to the gas supply line. Strive to ensure the steepness of growth layers with different compositions. However, in the conventional apparatus shown in FIG. 8, two bubblers themselves containing the same raw material liquid are required to meet such requirements, in other words, two identical piping systems 11 are required. And However, in the present invention, since the flow rate adjusting valve 42 for controlling the flow rate of the raw material gas is provided on the bubbler outlet side, if the number of the flow rate adjusting valves 42 is plural, a single bubbler can meet the above-mentioned object. That is, in the system shown in the lower side of FIG. 1, while the flow rate adjusting valve 42 currently in use is regulated by another flow rate adjusting valve 42 ', the flow rate required in the next step is defined. If valve 43 'is closed and valve 44' is opened and flowed toward exhaust line 46 beforehand, valve 43 'will be at the required timing.
When the valve 44 'and the valve 43 are rapidly closed, while the valve 44' and the valve 43 are rapidly closed, the raw gas having a sharply different flow rate is supplied through the raw gas supply line 45 though the number of the bubbler 41 is one. M
It can be fed into an OCVD reactor.

Further, if the sum of the flow rates of the two flow rate adjusting valves 42 and 42 'is controlled to be always constant, the hydrogen supply amount to the bubbler 41 can be kept constant, which allows the saturation degree of the organic metal. Since it is possible to suppress the fluctuation of the above, it is possible to obtain a result with good reproducibility even for a complicated and steep composition distribution. This has been confirmed by experiments.

FIG. 3 shows the raw material gas supply device of this embodiment.
The mechanical structure of the actual bubbler used in 30 is shown, but it is also devised. In the past, precise temperature control was difficult because of the heat conduction delay of the silicone oil for external application used to improve the heat conduction characteristics and the convection effect in the bubbler bottle 53 that contains the liquid metal. A copper block 54 having a blind hole with an inner diameter was prepared, and the bottle 53 was directly placed in this with a small amount of silicone oil. As a result, the above problems were alleviated and high temperature control characteristics could be obtained.
Further, since the ambient temperature of the bubbler 41 in the constant temperature bath 31 is high, a water cooling jacket 56 is attached to the Peltier element 55 brought into contact with the copper block 54.

FIG. 4 shows an example of the structural appearance of the semiconductor processing apparatus according to the present invention used in this embodiment. MOCV
The D-growth chamber 60 has a reaction furnace 63, and this reaction furnace 63 has a nested inner tube (not visible in this figure) described later and a quartz outer tube 64 visible in the figure in this embodiment. Is configured. In the reaction furnace 63, the raw material gas supply device 30
The raw material gas from is supplied. The connecting pipe itself for that purpose is not particularly modified and may have the same structure as that of a known structure. Therefore, in this figure, the illustration is omitted for simplification.

The MOCVD growth chamber 60 or the reaction furnace 63 is evacuated by a turbo molecular pump (not shown) via an exhaust chamber 65. Next to the exhaust chamber 65, the sample after MOCVD growth is not exposed to the atmosphere and the ECR is continued.
An ECR etching chamber 66 capable of etching is connected, and a load lock chamber 67 faces the ECR etching chamber 66, and a magnetic coupling rotation introducing machine 68 and a vacuum chamber 68 'also face the load lock chamber 67. In particular, a 4-inch gate valve 69 is used to connect the ECR etching chamber 66 with the load lock chamber 67 and the exhaust chamber 65 on both sides of the ECR etching chamber 66. Furthermore, in principle, each connection can support ultra-high vacuum. An ICF flange was used. The quartz outer tube 64 in the MOCVD growth chamber 60 is provided with a flange having a length of 1 m and a diameter of 10 cm, and a double O-ring with an exhausted middle portion is used for connection with the exhaust chamber 65. Further, the quartz outer tube 64 is supported by the linear guide roller 62, so that the quartz outer tube 64 can be easily attached and detached.

FIG. 5 shows a part of the MOCVD reactor, which is related to the inner quartz tube 70 housed in the outer quartz tube 64. This is also improved by the present inventor. Has been done. Generally, a vertical furnace called a barrel type is used in a MOCVD mass production furnace, but a horizontal furnace capable of growing one by one is more desirable for research and development. The apparatus of this embodiment also assumes such a horizontal furnace, and aims to solve the problems in the conventional horizontal furnace. That is, in the conventional horizontal MOCVD reaction furnace, the substrate 71 to be processed (thin film growth object) is usually placed in the reaction furnace with the crystal growth surface facing upward. Therefore, the polycrystalline powder adhered to the inner wall of the reactor falls on the crystal growth surface of the substrate,
This sometimes caused crystal defects. In particular, increasing the flow velocity of the reaction gas by narrowing the physical space between the reaction tube wall and the substrate is effective in increasing the steepness and uniformity of the growth layer. It becomes more and more likely that the polycrystalline powder will fall. Actually, according to the knowledge of the present inventor, the number of growth times per cleaning of the quartz tube was extremely limited.

Then, as shown in the figure, the substrate 71
Is preferably a molybdenum substrate holder 72, and a molybdenum clip 73 also holds the molybdenum substrate holder 72 with the crystal growth surface facing downward, and is housed in a quartz outer tube 64 (FIG. 4). A square hole 74 having a size for just accommodating the substrate 71 is formed on the upper surface of the rectangular cross section of 70, and the substrate 71 is placed in the square hole 74 while the peripheral portion of the substrate holder 72 is placed around the square hole 74. I dropped it. In addition, by this structure,
The substrate holder 72 can spatially separate the flow path in the inner pipe through which the raw material gas passes and the transfer path outside the inner pipe for transferring the substrate holder as described later.

The quartz inner tube is provided with a gas introduction port 75 at one axial end thereof (in this case, the end portion formed in a circular cross section).
Although the raw material gas is supplied from the raw material gas supply device 30 described above, the raw material gas also passes through the diffusion member 76 before reaching the substrate 71. The diffusing member 76 is used to convert the source gas into a uniform laminar flow, and has a rectangular outer shape in which quartz spheres having a diameter of about 2 mm are roughly sintered to a thickness of about 10 mm. However, in order to facilitate cleaning of the inside of the quartz inner tube 70, the diffusing member 76 is also removable. That is, an opening having a size that allows the diffusing member 76 to be just dropped is opened on the upper surface of the quartz inner tube 70, the diffusing member 76 is put into a predetermined position through this, and then the quartz cover 78 is removed with a molybdenum screw 78 ′. Fixed as possible.

Temperature sensor or thermocouple for measuring substrate temperature
When the substrate holder 72 is positioned at a predetermined position and the substrate 71 is dropped into the square hole 74, 79 is located exactly in the recess 80 provided in the substrate holder 72 and contacts the substrate holder at this portion. The placement position was adjusted and set to. A pair of forks 77, 77 for transferring the substrate is also shown in the figure, but this does not require any special devise in comparison with the known principle structure, and a structure suitable for design is manufactured. It was possible. The substrate 71 is transferred by the transfer forks 77, 77 from the etching chamber 66 or the load lock chamber 67 shown in FIG. In this device, the magnetic coupling rotation introducing machine 68 also shown in FIG.
And the vertical movement of the transfer forks 77, 77 was controlled by using the linear stage housed in the vacuum chamber 68 'related thereto.

Although not shown in the drawings, a dry rotary pump is used as a main exhaust system for the reaction furnace according to a known existing method, and a reaction is performed by interlocking a variable conductance valve driven by a stepping motor and a pressure system. The system pressure was controlled, and after the crystal growth, a high vacuum was maintained by a turbo pump.

By the way, usually, graphite which is in contact with the substrate is often used for heating the substrate. On the other hand, in this embodiment, the substrate holder 72 made of molybdenum is used. This is because with a sufficient physical strength, the substrate holder 72 can withstand screwing holes or some other machining in order to hold the substrate 71 downward in the reaction furnace. This is because I got it. But,
The heating efficiency of the substrate 71 is inferior to that of ordinary graphite. Therefore, by experiment, the suitability of the molybdenum substrate holder 72 was examined, but it was found that there was no problem. Even when the molybdenum substrate holder 72 is used as in this embodiment, the influence of the skin effect is reduced at a relatively low frequency of about 80 KHz, and the board thickness of the substrate holder is designed to be about 8 mm so that the magnetic flux Increasing the number of crossovers ensured uniform and relatively efficient heating. With the configuration shown, the high frequency power required to heat a 2-inch substrate is 3Kw at 700 ℃ and 4KW at 900 ℃.
Although it is about 20% larger than when graphite is used, since the substrate 71 is directly fixed to the molybdenum substrate holder 72, the growth temperature is highly uniform and the amount of adsorbed gas is smaller than that of graphite. The advantage of being able to reduce the residual oxygen concentration was also created, and higher quality crystal growth became possible.

Referring again to FIG. 4, in the semiconductor processing apparatus of this embodiment, the exhaust chamber 65 is adjacent to the MOCVD growth chamber 60 and does not break the vacuum (or at least not exposed to the atmosphere). The ECR etching chamber 66 is provided so that the substrates can be transferred to each other via the gate valve 69. Such a device configuration is extremely advantageous in processing an AlGaAs compound semiconductor, for example. In this type of processing target, the higher the aluminum concentration is, the more easily it is oxidized, and therefore it is difficult to form a buried structure by performing crystal regrowth after once exposing it to the atmosphere, or to form a low resistance ohmic contact layer. there were. However,
As in this embodiment, load lock chamber 67 and MOC
When the etching chamber 66 is provided between the VD growth chambers 60, even after the etching process is performed on the substrate on which the crystal growth is performed in a certain elementary process, the substrate surface is not oxidized in the next elementary process continuously. Crystal growth can be performed again.
This effect is considerably large, and a semiconductor laser having a favorable hetero interface, a compound semiconductor transistor with low ohmic contact, and the like can be manufactured with high productivity.

FIG. 6 shows the E used in the apparatus of this embodiment.
The main part of the internal structure of the CR etching chamber 66 is schematically shown. In order to realize an ECR ion source that can be used in an ultra-high vacuum environment as high as 1 × 10 ^-6 Pa, an ICF flange is provided at the microwave introduction port from the waveguide connection part 83 to which the microwave waveguide is connected. The ceramic window 84 of was used. This may be made of quartz. The reactive gas is a quartz nozzle.
It is guided to the plasma generation chamber 86 via 85, and the plasma generation chamber 86 is configured as an internal space of a nickel-plated stainless steel container or, more preferably, a conductive silicon carbide (SiC) container 87. Surrounding the plasma generation chamber 86 with SiC is effective in reducing contamination after etching. Further, the above-mentioned ceramic window 84 physically closes the opening provided at the bottom of the container 87 to form a spatially isolated state, while forming an inlet for microwaves. .

Magnetic generation means by electromagnet or permanent magnet
When microwaves are radiated through the ceramic window 84, which is a microwave introduction port, under the application of the DC magnetic field from 89, plasma is generated in a limited space by the plasma generation chamber 86 and the sheath electrode 91 provided above the plasma generation chamber 86. . The generated plasma is extracted while being accelerated by a pair of acceleration / extraction electrode pairs 90 provided further above the plasma generation chamber 86, and is applied to the substrate 71 supported by the substrate holder 72. In order to perform the etching, the substrate 71 together with the substrate holder 72 is transferred from the inside of the MOCVD growth chamber 66 to the center of the space inside the etching chamber by the transfer fork 77, and then the tip of the XYZ manipulator 92 schematically showing a part thereof. Scooped up by the etching chamber fork 93 fixed to the indium plate 95 which is in contact with the bottom of the water cooling plate 94.
Press the substrate holder 72 against. The indium plate 95 has an effect of reducing thermal resistance between the substrate holder 72 and the water cooling plate 94 for cooling the substrate holder. The fork 93 and the water cooling plate 94 are electrically insulated by the ceramic current introduction terminal 96, and as a result, the ion current can be measured. In the ECR etching chamber 66 having such a configuration, the potentials of the plasma generating chamber 86, the sheath electrode 91, and the accelerating electrode are +400 V,
The extraction electrode is set to zero potential (ground potential) and the applied magnetic field is 0.1
Under T, electric power is supplied while introducing Cl ₂ gas into the plasma generation chamber.
When irradiated with microwave of 50W, current density is 200μA / cm
An ion current of about ² was obtained, and a GaAs etching rate of about 60 nm / min was obtained.

In such a structure, it is possible to apply a DC voltage or a high frequency to the water cooling plate 94 to change the substrate bias state for etching, or to employ a so-called parallel plate type high frequency etching mode. Furthermore, as already reported, in order to reduce ion damage, the polarity of the extraction electrode 90 can be reversed and electron beam irradiation etching in a chlorine gas atmosphere is also possible.

If parallel plate type etching is adopted instead of ECR etching, according to the present invention, M
A configuration is proposed in which the reaction furnace itself in the OCVD growth chamber 60 is also used as an etching chamber.

FIG. 7 schematically shows the structure of the main part in such a case. That is, the illustrated structure is the MOCVD reaction furnace / etching chamber 100 that has both the functions of the MOCVD reaction furnace 63 and the etching chamber 66 described above. However, as shown by attaching the same reference numerals to the respective constituent elements in FIGS.
Since it may be the same as that shown in the above, the description on these individual components can be incorporated by reference to the parts already described.

The characteristics are that the reaction furnace itself is provided with an electrode structure and that the material of the outer tube 64, quartz, is used as the inter-terminal dielectric of the matching capacitor. The electrodes are provided as follows. First, on the outer wall of the quartz outer tube 64, the first metal plate 101 is provided so as to surround the outer wall for a predetermined length in the axial direction and to surround almost the entire circumference of the outer wall.
And a second metal plate 102 is provided on the inner wall side so as to face the first metal plate 101. However, most of the second metal plate 102 is provided not on the entire circumference of the inner wall of the quartz outer tube 64 but on a portion above the upper surface of the quartz inner tube 70 housed in the outer tube 64. The second metal plate 102 has a tongue-shaped conductor portion 103 extending from the second metal plate 102, which is in contact with the upper surface of the substrate holder 72 in the vicinity of the tip. On the other hand, the reaction tube inner tube 70
A third metal plate is provided on the inner wall of the substrate facing the substrate 71.
104 are provided.

With such a structure, the thickness of the quartz outer tube 64 between the first metal plate 101 and the second metal plate 102 is determined by connecting the first metal plate 101 to the first terminal conductor. , Second metal plate
It serves as an inter-terminal dielectric of a capacitor having 102 as a second terminal conductor. In fact, in the experiment conducted by the present inventor, a capacitor having a capacitance of about 20 pf was obtained. On the other hand, the first metal plate 10
Since 1 and the third metal plate 104 are both provided at positions that are easily accessible from the outside, the power feeding section 105 appropriately provided on the first metal plate 101 and the third metal plate that is generally the ground electrode
By applying high-frequency power between the capacitor 104 and 104, it is possible to realize a parallel plate type plasma generation mechanism including a matching capacitor.

When an AlGaAs-based quantum well type surface emitting laser was actually manufactured using the semiconductor processing apparatus according to the present invention as described above, extremely good results were obtained. In the raw material gas supply device (FIGS. 1 and 2) according to the present invention, as described above, the pressure adjusting loop, which is required for each system, is omitted, and the organometallic mixture is directly supplied to the flow rate adjusting valve. Therefore, a compound semiconductor having an arbitrary composition could be manufactured more rapidly and with good reproducibility. By the way, the characteristics of the surface-emitting laser actually manufactured are 15 μm ² to 20 μm.
With the m ² type, the threshold current was 3 to 5 mA and the threshold current density was about 1 KA, which was the highest level obtained at the present time. For this, the structure with the crystal growth surface of the substrate facing downward,
The other devices mentioned above have also contributed greatly.

[0044]

According to the present invention, in a semiconductor processing apparatus including a growth chamber for MOCVD and a source gas supply device for the growth chamber, the quality of a crystal growth film is improved, the composition is controlled precisely, the crystal defects are reduced, and the apparatus is improved. As a result, it is possible to obtain various advantages that are not available in the past, such as improvement in maintainability. In particular, in a specific aspect of the present invention, if an etching chamber is provided in parallel with the MOCVD reaction furnace, or if the MOCVD reaction furnace itself is also used as the etching chamber, unexpectedly in manufacturing various semiconductor devices. It eliminates the need to remove the oxide film formed, simplifying the manufacturing process,
The characteristics of the manufactured device itself can be dramatically improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a piping system in an example of a raw material gas supply device used in a semiconductor processing apparatus of the present invention.

FIG. 2 is a cross-sectional view schematically showing a main part configuration of the raw material gas supply device shown in FIG.

FIG. 3 is an explanatory diagram of an improved portion of the bubbler.

FIG. 4 is an explanatory diagram of an overall configuration of an apparatus according to a preferred embodiment of the present invention.

FIG. 5 is an explanatory diagram of a desirable structural example of the quartz inner tube of the MOCVD reactor.

FIG. 6 is a schematic structural diagram of an ECR etching chamber which is preferable to be incorporated in the apparatus of the present invention.

FIG. 7 is a schematic explanatory diagram of a desirable structural example when the MOCVD reactor is also used as an etching chamber.

FIG. 8 is an explanatory diagram of a main part of a piping system in a conventional source gas supply device for MOCVD growth.

[Explanation of symbols]

 30 Source gas supply device; 31 Constant temperature bath; 32 Flow control valve common to all systems; 33 Hydrogen supply line; 34, 35, 36, 37 valves; 38 Combined valve; 41 Bubbler; 42, 42 'Flow control valve; 43, 44, 43 ', 44' valves; 49 hydrogen exhaust line; 50 pressure gauge; 51 variable conductance valve; 53 bubbler bottle; 54 copper block; 56 water cooling jacket; 60 MOCVD growth chamber; 63 reactor; 64 quartz outer tube; 65 exhaust Chamber; 66 ECR etching chamber; 67 load lock chamber; 70 quartz inner tube; 71 substrate; 72 substrate holder; 74 square hole; 76 diffusion member; 77 transfer fork; 78 quartz cover; 83 microwave inlet port; 84 ceramic window; 85 Quartz nozzle; 86 Plasma generation chamber; 87 Conductive silicon carbide container; 90 Accelerating / extracting electrode pair; 91 Sheath electrode; 92 XYZ manipulator; 93 Etching chamber fork; 94 Water cooling plate 95 indium plate; 100 MOCVD reactor and etching chamber; 101 first metal plate; 102 second metal plate; 103 tongue-like conductive portions; 104 third metal plate; 105 power source.

Claims (13)

[Claims] 1. A metal-organic vapor-phase growth chamber including a metal-organic vapor-phase growth reactor, and a raw material for supplying a source gas obtained by bubbling liquid organic metal in a bubbler into the reactor. A semiconductor processing apparatus having at least a gas supply device; a flow rate adjusting valve for adjusting a flow rate of the raw material gas is inserted into a pipe from the bubbler outlet to the reactor in the raw material gas supply device. With;
A semiconductor processing apparatus, wherein a piping system from an outlet of the bubbler to a pipe connecting portion to the reaction furnace via the flow rate adjusting valve is housed in a constant temperature bath. 2. The apparatus according to claim 1, wherein a plurality of flow rate adjusting valves are provided at the outlet of the bubbler, and the raw material gas is selected via one of the plurality of flow rate adjusting valves. Is supplied to the above reaction furnace. 3. The apparatus according to claim 1, wherein the substrate to be subjected to the metal organic chemical vapor deposition in the reaction furnace is held by a substrate holder with its crystal growth surface facing downward. Semiconductor processing equipment characterized by the following. 4. The apparatus according to claim 3, wherein the reaction furnace comprises an outer tube and an inner tube housed in the outer tube, and the raw material gas flow passes through the inner tube. And the substrate holder accommodates the substrate by dropping it into the hole provided in the upper portion of the inner tube,
With this, the flow path of the raw material gas in the inner pipe and the substrate holder transfer path outside the inner pipe are separated from each other; 5. The apparatus according to claim 1, 2, 3 or 4, wherein an etching chamber is provided adjacent to the organometallic growth chamber so that the substrate can be transferred without breaking a vacuum. A semiconductor processing apparatus characterized by: 6. The semiconductor processing apparatus according to claim 5, wherein the etching chamber is an ECR etching chamber. 7. The apparatus according to claim 6, wherein said E
Microwaves introduced from a microwave introduction port to the CR etching chamber are introduced into the chamber through a quartz or ceramic window. 8. The semiconductor processing apparatus according to claim 6, wherein the plasma generation chamber in the etching chamber is formed of a conductive silicon carbide container. 9. The apparatus according to claim 6, 7 or 8, wherein a water cooling plate for cooling the substrate holder in the etching chamber is in contact with the substrate holder via an indium plate. Characteristic semiconductor processing equipment. 10. The apparatus according to claim 1, 2, 3 or 4, wherein a pair of metal plates for applying high frequency power for plasma generation are provided in the reaction furnace so as to sandwich the substrate. , Thereby allowing the reaction furnace to also function as an etching chamber having a parallel plate type plasma generation mechanism. 11. The apparatus according to claim 4, wherein a first metal plate is provided along the outer tube of the reaction furnace with predetermined dimensions in the axial direction and the circumferential direction, respectively, and the outer tube. A second metal plate that faces the first metal plate on the inner wall of the substrate and forms a capacitor between the first metal plate and the second metal plate, and extends from the second metal plate to contact the substrate holder A conductor portion and a third metal plate facing the conductor portion along the inner wall of the inner tube; the pair of electrodes for applying high-frequency power for plasma generation by the first and third metal plates. That is, the reaction furnace also functions as an etching chamber having a parallel plate type plasma generation mechanism; 12. A metal-organic vapor-phase growth chamber containing a metal-organic vapor-phase growth reactor, and a raw material for supplying a source gas obtained by bubbling liquid organic metal in a bubbler into the reactor. A semiconductor processing apparatus having at least a gas supply device; a pair of metal plates for applying high-frequency power for plasma generation are provided in the reaction furnace so as to sandwich the substrate, whereby the reaction furnace is A semiconductor processing apparatus characterized by also functioning as an etching chamber having a parallel plate type plasma generation mechanism. 13. A metal-organic vapor-phase growth chamber containing a metal-organic vapor-phase growth reactor, and a raw material for supplying a raw material gas obtained by bubbling liquid organic metal in a bubbler into the reactor. A semiconductor processing apparatus having at least a gas supply device; the reaction furnace includes an outer tube and an inner tube housed in the outer tube, and the raw material gas flow passes through the inner tube. In addition, the substrate holder for holding the substrate to be the target of organometallic growth stores the substrate with the crystal growth surface of the substrate facing downward so as to drop the substrate into the hole provided in the upper portion of the inner tube;
In the reaction furnace, a first metal plate along the outer tube of the reaction furnace along a predetermined dimension in the axial direction and the circumferential direction, and the first metal plate on the inner wall of the outer tube A second metal plate facing each other and forming a capacitor between the first metal plate, a conductor portion extending from the second metal plate and contacting the substrate holder, and an inner wall of the inner pipe. A third metal plate along the conductor portion opposite the conductor portion;
The third metal plate serves as a pair of electrodes for applying high-frequency power for plasma generation, so that the reaction furnace also functions as an etching chamber having a parallel plate plasma generation mechanism. Processing equipment.