JPH0831418B2 - Semiconductor manufacturing equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a semiconductor manufacturing apparatus for growing a compound semiconductor layer in a vacuum chemical epitaxy (VCE) system.

[Conventional technology]

In recent years, compound semiconductors, especially III-V compounds (eg G
The demand for aAs) is increasing as it has superior performance to conventional silicon semiconductors. As a method for producing such a compound semiconductor, the atoms necessary for the compound for epitaxial growth are evaporated from a solid material by a heat gun in an ultrahigh vacuum, and this is made to collide with the substrate in the form of a molecular beam, The molecular beam epitaxy ([MBE] Molecular Beam Epitaxy) method of growing a film on top, or vapor of metal methyl or ethyl compound is sent by carrier gas such as H ₂ and introduced into a reaction chamber at atmospheric pressure or reduced pressure, where After being mixed with a group V hydrogen compound, it is reacted on a heated substrate to grow crystals, and metal organic CVD ([MOCVD] Metal Organic
Chemical Vapor Deposition) method, etc.

[Problems to be solved by the invention]

However, of the above two methods, the MBE method requires an ultrahigh vacuum of the order of 10 _-11 torr.
Since downtime occurs when refilling the raw material, a substrate rotation mechanism is required to perform uniform growth, etc.
Mass production is difficult, and it is difficult to supply enough to meet market demand, which is not suitable for mass production. Therefore, although the MOCVD method has been attracting attention and is actually used, since this method is a process in the laminar flow region, distribution is likely to occur in the flow direction, and it is difficult to analyze the flow at the time of scale up. There is a drawback that the reaction gas is expensive and the utilization efficiency of the reaction gas is poor due to its growth mechanism. In addition, since the use efficiency of the reaction gas is low, a large amount of unreacted gas (toxic gas) is generated, and since the carrier gas is added to the unreacted gas, a large amount of toxic waste gas is generated, which is largely discarded. It's a problem.

[Problems to be solved by the invention]

As described above, the MBE method and the MOCVD method each have drawbacks, and there is a demand for providing a semiconductor manufacturing apparatus that completely eliminates these drawbacks. Therefore, the present inventors succeeded in developing a semiconductor manufacturing apparatus combining the advantages of the MBE method and the MOCVD method prior to the present application, and already applied for a patent (Japanese Patent Application No. 63-
No. 191060). This semiconductor manufacturing apparatus has a structure as shown in FIGS. 4 and 5. In these figures, 101 is a vacuum chemical epitaxy.
Pitaxy) system, a reaction chamber 102 is provided in the vacuum chamber 101. The reaction chamber 102 has a floorboard 10
6, a peripheral wall 107, and an upper plate 108 that is placed so as to be slidable in one direction. This upper plate 108 has a hole
108a are provided, and each of the holes 108a has a disk-shaped Ga
As substrate 113 is detachably attached. An exhaust port 110 is provided along the outer periphery of the peripheral wall of the reaction chamber 102 with a predetermined gap. The total area of these exhaust ports 110 is set to approximately 4% of the area of the upper plate 108 of the reaction chamber 102. Nozzles 109 are provided in the floor plate 106 at regular intervals, and holes 1 are provided in the ceiling of the first diffusion chamber 104 disposed below the reaction chamber 102.
It communicates with 09 or 134. This hole 109 is the first diffusion chamber
The hole 134 communicates with the inside of the first diffusion chamber 104, and the hole 134 communicates with a second diffusion chamber 124 provided below the first diffusion chamber 104 through a duct 119 penetrating the inside of the first diffusion chamber 104. . First diffusion chamber 104
A raw material injection pipe 121 communicates with the inside, and this raw material injection pipe 1
A group III compound (reaction gas) such as trimethylgallium (TMGa) or triethylgallium (TEGa) is fed into the first diffusion chamber 104 from 21. The second diffusion chamber 124 has an opening on the lower side, and an exhaust valve 136, which is a poppet valve for opening and closing the opening, is provided in the opening so as to be movable back and forth. A raw material injection pipe 122 is connected to the side wall of the second diffusion chamber 124.
-Type, p-type dopant or triethylaluminum (TE
A group III compound such as Al) is fed into the second diffusion chamber 124. Reference numeral 142 is a supply pipe for supplying a group V compound such as AsH ₃ into the reaction chamber 102.
The holes a and the holes 142b are formed in two rows on the left and right with a constant spacing. Reference numeral 105 is a heater disposed above the upper plate 108 of the reaction chamber 102, and 105c is a soaking plate. In this semiconductor device, for growth and formation of the MESFET epitaxy layer, a substrate 113 (the surface of which is on the lower side) is attached to the reaction chamber 102, and then the inside of the vacuum chamber 101 is filled with a vacuum degree of 1 × 10 ⁻⁷ Torr. In addition to the following vacuum state, electric charges are applied to the heater 105 to heat the heater 105. And the substrate temperature is 500
A group V compound such as AsH ₃ is fed into the supply pipe 142 at about ° C, and is discharged into the reaction chamber 102 through the holes 142a and 142b. The group V compound supplied into the reaction chamber 102 is the substrate 1
Cross the surface of 13 toward the exhaust port 110, between which A
sH ₃ repeatedly collides with the wall of the reaction chamber, which is a hot wall, and thermally decomposes to As ₂ . Then, after the substrate temperature reaches a predetermined process temperature (600 to 650 ° C.), a group III compound such as triethylgallium (TEGa) is sent into the first diffusion chamber 104 from the raw material injection pipe 121 of the reaction chamber 102, and a uniform state is obtained. Then, the liquid is discharged from the nozzle hole 109 toward the substrate 113 with a uniform molecular density. At this time, since the mean free path of the group III compound molecules is set to be longer than the distance from the orifice to the wafer, the group III compound molecules reach the substrate without being scattered by collision of the raw material molecules. To do. The group III compound molecules come into contact with the surface of the substrate 113 together with As _{2 and} grow as an undoped gallium arsenide (GaAs) layer or the like. Unconsumed compounds that do not come into contact with the substrate 113 are discharged to the outside from the exhaust port 110 and sucked to the side of the vacuum chamber 101 by the exhaust means. Next, an n-type dopant is discharged from the second diffusion chamber 124 into the reaction chamber 102 together with the above-mentioned group III or group V compound or alone to grow an n-type active layer on the surface of the undoped GaAs layer. . After that, with the gas supply stopped,
Hold for 15 minutes. Then, after cooling the substrate 113, it is taken out from the reaction chamber (vacuum chamber 101) 102. In this way, a III-V compound semiconductor having a uniform MESFET semiconductor layer is obtained.

However, in the semiconductor manufacturing apparatus having the above structure, when growing a large-area substrate or a large number of substrates, that is, when the distance between the supply pipe and the exhaust port becomes long, a V group such as AsH ₃ is used. V between the compound supply pipe and the exhaust port
There is a drawback that a distribution of the molecular density of the group compound is generated, and it is sometimes difficult to form a uniform semiconductor layer (when growing at a low V / III ratio). Further, as shown in FIG. 6, the outer peripheral edge portion of the substrate 113 is supported by the substrate holding portion composed of the step portion 108b over the entire circumference, so that the arrow from the lower side portion of the reaction chamber 102 is shown. The molecular beam traveling upward like X is blocked by the step portion 108b and does not reach the outer peripheral edge portion of the substrate 113. Therefore, as shown in FIG. 7, only the outer peripheral edge portion of the substrate 113 remains as an unprocessed portion, which is uneconomical.

The present invention has been made in view of such circumstances, and an object thereof is to provide a semiconductor manufacturing apparatus capable of uniformly distributing all reaction gases in a reaction chamber.

[Means for solving problems]

To achieve the above object, the semiconductor manufacturing apparatus of the present invention is provided with a vacuum chamber, a reaction chamber provided in the vacuum chamber, and a ceiling part of the reaction chamber so as to hold a substrate in contact with a reaction space. Of the substrate holding part, a heating body provided above the reaction chamber so as to heat the substrate, a reaction gas diffusion chamber provided below the reaction chamber, the reaction gas diffusion chamber and the reaction chamber. A plurality of communication holes which are provided on one surface at a predetermined interval at the boundary portion and allow the two chambers to communicate with each other, and a first end which extends into the reaction gas diffusion chamber and has a front end opening which opens toward the bottom surface of the reaction gas diffusion chamber. A reaction gas supply pipe,
A collar portion provided horizontally on the outer peripheral portion of the tip opening of the first reaction gas supply pipe, a second diffusion chamber provided below the reaction gas diffusion chamber, and a ceiling portion of the second diffusion chamber. A plurality of communication pipes extending from the above to each communication hole of the reaction gas diffusion chamber so as to form a gap between the reaction gas diffusion chamber and the hole wall, and a reaction gas supply pipe for supplying the second reaction gas to the second diffusion chamber. Take the configuration to prepare.

[Action effect]

That is, in this semiconductor manufacturing apparatus, a reaction gas diffusion chamber is newly provided on the lower side of the reaction chamber, the first reaction gas supply pipe is extended in the reaction gas diffusion chamber, and its tip opening is located on the bottom surface of the reaction gas diffusion chamber. A flange portion is horizontally formed on the outer periphery of the front end opening. Therefore, the first reaction gas such as AsH ₃ is blown downward from the first reaction gas supply pipe into the reaction gas diffusion chamber having the gas dispersion effect, and then abuts on the brim portion and moves along the brim portion. Then, it spreads horizontally in all directions and is uniformly diffused in the gas diffusion chamber, and then is supplied into the reaction chamber through a communication hole provided at a boundary between the gas diffusion chamber and the reaction chamber. Therefore, the reaction gas is supplied to the reaction chamber in a uniform molecular beam state. That is, in this semiconductor manufacturing apparatus, the downward opening of the first reaction gas supply pipe, the collar portion provided on the outer periphery of this opening, the reaction gas dispersion effect of the reaction gas diffusion chamber, the reaction gas diffusion chamber and the reaction chamber The group V reaction gas such as AsH ₃ is supplied to the reaction chamber in a uniform molecular beam state by the action of the plurality of communication holes provided on the one surface at a predetermined interval at the boundary portion of. The second reaction gas made of TEAl or the like and the third reaction gas made of TEGa or the like are mixed in the second diffusion chamber provided below the reaction gas diffusion chamber. Then, it is uniformly supplied to the reaction chamber. In this case, a recess is formed at the bottom of the second diffusion chamber and a baffle plate is provided near the upper side of the opening of the recess to form a space formed by the recess and the baffle plate in the third diffusion chamber. The second reaction gas supply pipe and the third reaction gas supply pipe are attached to the peripheral wall of the diffusion chamber with the openings substantially facing each other, and the second reaction gas and the third reaction gas are supplied from the both openings. When the gas is blown into the third diffusion chamber and mixed, and then the gas is supplied to the second diffusion chamber through the gap between the baffle plate of the second diffusion chamber and the opening of the concave portion, the mixing of the two gases is further improved. Will be done. In addition, a cutout hole having substantially the same size as the substrate is formed in the ceiling of the reaction chamber, and substrate supporting pieces are provided at predetermined intervals along the circumference of the hole in the peripheral portion of the hole facing the reaction chamber. In some cases, the portion of the substrate hidden by the substrate support piece is extremely smaller than in the case where the support portion is provided on the entire inner circumference of the hole portion, so that substantially the entire substrate surface can be used for forming the semiconductor layer.

 Next, examples will be described.

〔Example〕

1 (A), (B), and (C) show the configuration of an embodiment of the present invention. In FIG. 1 (A), reference numeral 1 is a stainless steel cylindrical vacuum chamber in a vacuum chemical epitaxy system, and in this vacuum chamber 1, a reaction chamber made of carbon graphite whose wall surface is coated with silicon carbide. 2, the reaction gas diffusion chamber 3 made of carbon graphite as described above, and the second diffusion chamber 4 made of stainless steel are arranged in an integrated manner.
The reaction chamber 2 is made of carbon graphite so that the wall surface thereof becomes hot wall by the heating by the heater 5 and the molecular particles of the reaction gas do not adhere and are reflected even if the molecular beam of the reaction gas collides there. It is composed of a floor board 6, a peripheral wall 7 and a ceiling board 8. A plurality of communication holes 9 are formed in the floor plate 6 at regular intervals, so that the reaction chamber 2 and the reaction gas diffusion chamber 3 below the reaction chamber 2 are in communication with each other. A band-shaped exhaust port 10 is formed on the upper portion of the peripheral wall 7 along the circumference. Further, as shown in FIG. 1 (B), the ceiling plate 8 is provided with four circular notch holes 11, and the lower peripheral portion of each notch hole 11 is shown in FIG.
As shown in the figure, the substrate support pieces 12 are provided so as to project at 1/4 intervals in the circumferential direction. The four substrate supporting pieces 12 constitute a substrate supporting portion. Then, the circular substrate is formed in the cutout hole 11.
13 is detachably inserted and supported by the substrate support piece 12.

The reaction gas diffusion chamber 3 provided below the reaction chamber 2 is
Similar to the reaction chamber, the wall surface is designed to be a hot wall, and is composed of a floor plate, a peripheral wall, and a ceiling plate composed of the floor plate 6 of the reaction chamber 2. A first reaction gas supply pipe 15 extends from the outside into the reaction gas diffusion chamber 3, and a tip portion thereof is bent downward and an opening 16 thereof is opened downward. A disc-shaped brim portion 17 is horizontally formed on the outer peripheral portion of the opening 16. This allows the opening
The first reaction gas discharged from 16 is spread horizontally along the brim 17 in all directions. A second diffusion chamber 4 is formed below the reaction gas diffusion chamber 3.

The second diffusion chamber 4 is made of stainless steel because the wall surface does not need to be hot wall, and is composed of a bottom plate 18, a peripheral wall 7, and a ceiling plate composed of the bottom plate 14 of the reaction gas diffusion chamber 3. Has been done. A plurality of communication pipes 19 made of stainless steel extend from the ceiling plate of the diffusion chamber 4 toward a plurality of communication holes 9 provided in the same manner as the ceiling plate 6 of the reaction gas diffusion chamber 3. In this case, the communication pipe 19
And a gap is formed between the wall of the communication hole 9 and the hole wall. The presence of the communication pipe 19 brings the diffusion chamber 4 and the reaction chamber 2 into communication with each other, and the reaction gas diffusion chamber 3 and the reaction chamber 2 are formed by the gap between the communication pipe 19 and the wall of the communication hole 9. And are in communication. In addition, the second
In the bottom of the diffusion chamber 4, the central portion is formed in the recess 20, and the tip of the second reaction gas supply pipe 21 and the third reaction gas supply pipe 22 are formed in the peripheral wall portions of the recess 20 facing each other. Openings 21a, 22a
Is open in a relative state. A baffle plate 23 is provided slightly above the opening of the recess 20 so as to face the opening, and the baffle plate 23 and the recess 20 form a third baffle plate.
A diffusion chamber 24 is formed. In the third diffusion chamber 24, the second and third reaction gases are in a uniformly mixed state by the action of the blowing pressure and the action of the baffle plate 23, and in that state, the baffle plate 23 and the recess 20 are opened. From the gap between
Enter diffusion room 4. Then, the mixed gas is further uniformly mixed in the second diffusion chamber 4, and then the communication pipe 19
To reach the reaction chamber 2. In FIG. 1 (A), 5 is a plate-shaped heater, and 5a is a soaking plate, and the substrate 13 is heated from above mainly by radiant heat to a temperature at which a semiconductor compound can grow on the substrate surface.
As shown in FIG. 1 (C), the heater 5 is constructed by alternately providing streak cuts 5'on a plate-shaped carbon graphite and attaching electrodes on both ends. The heater 5 is capable of uniform heating in a planar manner, but the uniform heating plate 5a provided below the heater 5 makes the planar heating even more uniform.

In operation, for growth and formation of the MESFET epitaxy layer, as shown in FIG. 1 (A), the substrate 13 (having the surface facing downward) is attached to the reaction chamber 2, and then the inside of the vacuum chamber 1 is set to a high vacuum chamber. In addition to the state, the heater 5 is energized to generate heat. First reaction gas supply pipe 15 at substrate temperature of about 500 ℃
A group V compound gas such as AsH _{3 is} fed into the gas diffusion chamber 3 from inside to make a uniform diffusion state inside. Then, it is discharged into the reaction chamber 2 through the communication holes 9 formed in the ceiling of the reaction gas diffusion chamber 3 at even intervals. In the reaction chamber 2, a gas such as AsH ₃ comes into contact with the surface of the substrate 13 and diffuses toward the exhaust port provided along the circumference of the peripheral wall of the reaction chamber 2 in a strip shape along the entire circumference. Flowing. During that time, AsH _{3 and the} like are thermally decomposed to As ₂ . Then the substrate temperature is
After the temperature reaches 00 to 650 ° C., a group III compound gas such as triethylgallium (TEGa) is fed into the third diffusion chamber 24 from the second reaction gas supply pipe 21, and at the same time, the third reaction gas supply pipe 22 A group III compound gas such as triethylaluminum (TEAl) is fed into the third diffusion chamber 24, mixed with the above reaction gas, and then supplied into the second diffusion chamber 4 in that state.
These come in contact with As _{2 on} the surface of the substrate and grow as an undoped gallium arsenide (GaAs) layer. The substrate 13
Unconsumed compounds that do not come into contact with are discharged to the outside through the exhaust port 10 and are discharged by the exhaust means. In this case, since the exhaust port 10 is formed in a strip shape around the entire peripheral wall of the reaction chamber 2, the unconsumed gas is uniformly discharged from the entire peripheral wall of the reaction chamber 2. It contributes to the uniform distribution of the reaction gas. Next, the n-type dopant is added to the above II.
The undoped material can be obtained by discharging the second diffusion chamber 4 into the reaction chamber 2 together with the group I or V compound or alone.
An n-type active layer is grown on the surface of the GaAs layer. After that, the gas supply is stopped for a predetermined time and the substrate 13 is cooled and then taken out from the reaction chamber 2. In this way, a semiconductor having a uniform MESFET semiconductor layer can be obtained.

Although four substrates 13 are used in the above embodiment, the number of substrates 13 is not limited to this, and one substrate may be used, or a plurality of substrates may be used. Absent.

As described above, according to this embodiment, the reaction chamber 2 having a smaller capacity than the vacuum chamber 1 is provided in the vacuum chamber 1, and the substrate 13 is provided in the reaction chamber 2.
In this state, the reaction gas is supplied in the form of molecular beam to grow the reaction gas, so that the waste gas is reduced and the utilization efficiency of the reaction gas can be significantly improved. Also,
In this apparatus, since the vacuum chamber 1 can be evacuated to a high vacuum, even a group III compound having a low vapor pressure can be directly gasified and used.
Therefore, the carrier gas for transporting the compound becomes unnecessary, and the exhaust gas of the used gas can be exhausted in a small amount. Particularly, in the above apparatus, the reaction gas diffusion chamber 3 is newly provided, the first reaction gas supply pipe 15 is disposed downwardly inside this, and the flange portion 17 is provided at the tip opening 16 to uniformly diffuse the reaction gas. The reaction gas is supplied to the reaction chamber 2 in a uniform state so that a uniform semiconductor layer can be formed on a large area substrate or a large number of substrates without rotating the substrate or the susceptor. Can be realized.

[Brief description of drawings]

FIG. 1 (A) is a cross-sectional view showing the structure of an embodiment of the present invention, FIG. 1 (B) is a plan view of the substrate holding portion, and FIG. 1 (C) is an enlarged plan view of the heating body. 2, FIG. 2 is a cross-sectional view of the substrate holding portion, FIG. 3 is a plan view for explaining the arrangement state thereof, FIG.
FIG. 7 is an enlarged view of the main part, FIG. 6 is a sectional view of the substrate holding part, and FIG. 7 is a plan view for explaining the holding state. 1 ... vacuum chamber, 2 ... reaction chamber, 3 ... reaction gas diffusion chamber, 4 ... second diffusion chamber, 5 ... heater, 9 ... communication hole, 10 ... exhaust port, 11
... Notched hole, 12 ... Substrate support piece, 13 ... Substrate, 15 ... First reaction gas supply pipe, 16 ... Opening, 17 ... Collar portion, 19 ... Communication pipe, 21, 2
2 ... Second and third reaction gas supply pipes, 23 ... Baffle plate, 24 ... Third
Diffusion room

Claims (3)

[Claims] 1. A vacuum chamber, a reaction chamber provided in the vacuum chamber, a substrate holding unit provided at a ceiling of the reaction chamber so as to hold the substrate in contact with the reaction space, and the substrate is heated. A heating element provided above the reaction chamber so that a reaction gas diffusion chamber provided below the reaction chamber,
A plurality of communication holes which are provided on one surface at a predetermined interval at the boundary between the reaction gas diffusion chamber and the reaction chamber and allow the two chambers to communicate with each other; A first reaction gas supply pipe that is open toward the front, a flange portion that is horizontally provided on the outer peripheral portion of the tip opening of the first reaction gas supply pipe, and a lower side of the reaction gas diffusion chamber. A second diffusion chamber, a plurality of communication pipes extending from the ceiling of the second diffusion chamber to each communication hole of the reaction gas diffusion chamber so as to form a gap between the second diffusion chamber and the hole wall; A semiconductor manufacturing apparatus comprising a reaction gas supply pipe for supplying a second reaction gas to a diffusion chamber. 2. A recess is formed in the bottom of the second diffusion chamber, and a second reaction gas supply pipe and a third reaction gas supply pipe are attached to the peripheral wall of the recess, and the opening of the recess is formed. The semiconductor manufacturing apparatus according to claim 1, wherein a baffle plate is provided in the vicinity of the upper side so as to face the opening. 3. A hole having a size substantially the same as the size of the substrate is formed in the ceiling of the reaction chamber, and a substrate supporting piece is provided at a peripheral portion of the hole facing the reaction chamber at predetermined intervals along the circumference of the hole. The semiconductor manufacturing apparatus according to claim 1, wherein a substrate holding part made of is formed.