JPH0472717A - Semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To make it possible to feed the source gas of constant concentration at all times by a method wherein a first pressure control device or a first flow rate control device is provided on the flow-in side or the flow--out side of bubbler carrier gas. CONSTITUTION:The pressure of the up-stream side of the bubbler 14 for feeding of source gas is measured by the first pressure measuring part 2a, and the flow rate is controlled by the first computing part 7a so as to bring the pressure constant. Also, the flow rate is measured by the first flow rate measuring part 3a, computed by the second computing part 7b, and the flow rate is controlled by the second flow rate controlling part 8b so as to obtain a constant flow rate. Thus, the first pressure control device 12a and the first flow-rate control device 15a are provided on the flow-in side and the flow-out side of the carrier gas of the bubbler 14, and as a result, the flow rate of the carrier gas can be made constant, the pressure in the bubbler is also made constant, and the source gas of constant concentration can be fed at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor manufacturing apparatus that is applied to a semiconductor crystal growth apparatus or the like having an organometallic gas supply line.

[Conventional technology]

FIG. 5 shows a first conventional example, which is a flow rate control device used in a raw material supply line using evaporation or sublimation of a liquid source (for example, trimethyl gallium) or a solid source (for example, trimethyl indium). That is, it shows a mass flow controller. This mass flow controller 31 includes a flow rate measuring section 32 and a flow rate setting section 33.
, a display section 34, a calculation section 35, and a flow rate control section 36. This mass flow controller 31 is
The flow rate measurement unit 32 captures the flow rate of the gas as the movement of heat flowing through the capillary tube, converts the amount of heat movement into voltage, and measures it. 37
is a heater that heats gas through a capillary tube. The voltage difference between this measured voltage and the voltage corresponding to the flow rate of the flow rate setting unit 33 is calculated by the calculation unit 35, and the flow rate control unit 3 consisting of a diaphragm valve or a solenoid valve calculates the voltage difference so that the voltage difference becomes 0.
6 to adjust the gas flow rate. Note that a linear relationship is established between the voltage corresponding to the set flow rate and the actual gas flow rate.

Figure 6 shows a second conventional example, which is a device for keeping the supply source concentration constant in a raw material supply line using evaporation or sublimation of liquid or solid sources (Miyamoto et al.: Journal of Crystal Growth 93). 1988)
35.3-358). This device includes a carrier gas line 41, a mass flow controller 42, a source 43, a bubbler 44 for source supply, and a needle valve 4.
5. It consists of a main gas line 46, a vent gas line 47, a source line 48, and a dummy line 49.

This device has two features: the source line 48 between the first point
A dummy line 49 is provided to flow the same 2ii amount of carrier gas, and before growth, the source line 48 and the dummy line 49 are connected to the vent gas line 47 and the main gas line 46, respectively, by switching the changeover switches (valves) 50 to 52. In addition, during growth, they are connected to the main gas line 46 and vent gas line 47, respectively.

That is, even when performing epitaxial growth with different compositions, the main gas line 46 and the vent gas line 4
As a result of the same flow rate of gas always flowing into the main line 46 and the vent line 47, pressure fluctuations and pressure differences between the main line 46 and the vent line 47 can be reduced, and compositional fluctuations at the epitaxial interface can be reduced. Second, by providing the needle valve 45 on the source side of the main gas line 46 and vent gas line 47 of the source line 48, a predetermined pressure can be obtained in the bubbler 44.

Further, it is difficult to sufficiently reduce the pressure fluctuation and pressure difference between the main gas line 46 and the vent gas line 47 by improving only the first point due to the viscosity of the fluid, but by using the needle valve 45, the It has the feature of reducing pressure fluctuations. For example, vent gas line 4
It is possible to prevent gas from flowing back toward the source line 48 when the pressure of the main gas line 46 is higher than that of 7, and it is possible to reduce compositional fluctuations at the epitaxial interface.

The third conventional example uses the calculation formula shown in equation (1) (Miyamoto et al.: Journal of Crystal Growth 93 (1988)
353-358).

(The following is a blank space) LxPB Here, L = 22400 cc/mol, PS is the pressure of the source, PB is the pressure inside the source supply bubbler 44, and F is the carrier gas flow rate (cc/win).

From this 2fi+, the molar flow rate of the source is calculated and the growth conditions are determined. Furthermore, when a solid source is used as the source, as the remaining amount of the source decreases, the molar flow rate decreases with respect to the calculated value M, so the molar flow rate has been determined from a conversion diagram as shown in FIG.

[Problem to be solved by the invention]

We have been developing semiconductor lasers with a superlattice structure in which semiconductor crystals of various compositions are stacked in the form of a Fi[film. There was a need.

In particular, in crystal growth using the MOVPE method, the raw material source is a liquid or solid, and a method is used in which a carrier gas is flowed inside the source to dissolve the vapor of the raw material source into the carrier gas and take it out. There is.

In order to stably supply the raw material gas, it was necessary to keep the flow rate, pressure and temperature of the carrier gas, and the temperature of the raw material source constant. Furthermore, in order to obtain semiconductor crystals in each layer constituting the superlattice structure with good reproducibility, it was necessary to actually measure the amount of source contained in the carrier gas.

The mass flow controller 31 shown in the first conventional example is
The flow rate control unit 36 uses a diaphragm valve or an i-magnetic valve to control the flow rate, but because the gauging area is small, there is a problem in that pressure fluctuations on the mass flow gas outflow side cause pressure fluctuations on the mass flow gas inflow side. .

In addition, the conventional mass flow controller 31 exists only as a single constant flow mass flow device that keeps the flow rate constant, and when configuring a constant pressure mass flow device that keeps the pressure constant on the gas outlet side of the mass flow device, the pressure detection unit and Separate products such as flow rate controllers must be combined, and there is no integrated product like a constant flow mass flow device. moreover,
When constructing a low-pressure mass flow device, if the pressure detection section and the flow rate control section are separated, it is not possible to simultaneously measure the gas flow rate, temperature, and pressure and calculate the molar flow rate of the source. This is because correct results cannot be obtained unless measurements are taken at the same location due to effects such as adiabatic expansion. Furthermore, if the pressure detection section and flow rate control section are separated, it is necessary to incorporate a pressure gauge into the piping system, which complicates the piping and increases the possibility of leaks. Since the wiring between the control parts is long, it is easily affected by external noise, making it difficult to measure with high precision.

In addition, in the feature of the second fish of the second conventional example, a needle valve 45- is used to prevent gas backflow, but in order to keep the molar flow rate of the source constant, the source line 45- is used.
It is necessary to control the flow rate of the carrier gas B and the pressure inside the bubbler 44 independently and at constant values. For this purpose, a needle valve 45 is used to maintain the pressure inside the bubbler 44 at a constant value.
It is necessary to continuously make fine adjustments to the source, but it is difficult to improve the accuracy of the adjustment and this results in fluctuations in the amount of sauce supplied. Furthermore, when growing crystals with different compositions, it is necessary to change the flow rate of the carrier gas, but the difference between the flow rate of the carrier gas and the source mole 2I! When the L amount is made proportional, it is necessary to keep the pressure inside the bubbler 44 constant regardless of changes in the flow rate of the carrier gas.

Further, in order for Equation (1) of the third conventional example to hold true, the source must be sufficiently sublimated and the molar flow rate of the source in the gas must be in a saturated state. However, especially in the case of a solid source, when the flow rate of the carrier gas is increased, the gas flows out of the bubbler 44 before the source molar flow rate of the carrier gas reaches the plate pressure, and the PSO value of 1+ decreases. Therefore, the actual molar flow rate decreases with respect to the calculated value, and the actual molar flow rate cannot be grasped.Also, when a solid source is used as the source, as the residual amount of the source decreases, the actual molar flow rate decreases. Because the source molar flow rate decreases, a conversion diagram showing the relationship between the source residual amount and the source molar flow rate is used.However, it is difficult to accurately grasp the residual amount of the source, and the bubbler 44
Because the flow of gas in the source changes depending on the filling state of the source, the molar flow rate often deviates from the value in the conversion chart.

Further, when the remaining amount of sauce in the bubbler 44 becomes 40% or less, the molar flow rate suddenly decreases as shown in FIG. The remaining amount of the source when the molar flow rate decreases is greatly affected by the filling state, and the remaining amount varies from 50% to 10%.
%, it is difficult to predict when the molar flow rate will decrease. Therefore, at present, the source has no choice but to be converted when the remaining capacity of the source is about 80%. Similarly, it is difficult to determine the remaining amount of liquid sauce.

Therefore, an object of the present invention is to provide source supply piping for a raw material supply line that can supply source gas at a constant concentration, calculate the molar amount of sauce, and predict when to replace the bong. An object of the present invention is to provide a semiconductor manufacturing apparatus having a system.

[Means to solve the problem]

The semiconductor manufacturing apparatus according to claim 11 includes a first pressure measuring section and a first pressure measuring section that uses a measured value of the first pressure measuring section as a human power signal.
A first pressure side, which is provided with a calculation section and a first flow rate control section that responds to the output signal of the first calculation section. I device, a first flow rate measurement section, a second calculation section which receives the measured value of the first flow rate measurement section as an input signal, and a second calculation section located downstream of the first flow rate measurement section; a first flow rate control device including a second flow rate control unit that responds to an output signal of a calculation unit of the first pressure control device and the first flow rate side? One of the No. 11 devices is placed upstream of the bubbler for supplying source gas, and the other is placed downstream.

The semiconductor manufacturing apparatus according to claim (2) includes a first temperature measurement section, a second flow rate measurement section located downstream of the first temperature measurement section, and a second flow rate measurement section downstream of the second flow rate measurement section. The measured values of a third flow rate control section, a second pressure measurement section, the first temperature measurement section, the second flow rate measurement section, and the second pressure measurement section are used as input signals, and a second pressure control device including a third calculation section that provides an output signal to the third flow rate control section, a second temperature measurement section, and a third pressure measurement section downstream of the second temperature measurement section; a flow rate measurement section, a fourth flow rate control section located downstream of the third flow rate measurement section, a third pressure measurement section, the second temperature measurement section, the third flow rate measurement section, and the a second flow rate control device including a fourth calculation unit that receives each measured value of the third pressure measurement unit as an input signal and provides an output signal to the fourth flow rate control unit; and the second pressure side W a fifth calculation unit that calculates the molar flow rate of the source from the difference in the flow rate of the fluid flowing through the device and the second flow rate control device; and a display unit that displays the measured value and the calculation result, One of the pressure control device and the second flow rate ms device is arranged on the upstream side of the bubbler for supplying the source gas, and the other one is arranged on the downstream side, and the second pressure measurement unit is arranged to control the third flow rate. the third pressure measuring section is located on the bubbler side with respect to the fourth flow rate control section;
The second flow rate control device is controlled by the output signal of the arithmetic unit.

[Effect]

According to the semiconductor manufacturing apparatus of claim f1), the first pressure measuring section measures the pressure on the upstream side or the downstream side of the bubbler for supplying the source gas, and the pressure is made constant by the output of the first calculating section. The flow rate is controlled by the first flow rate control section as follows. Further, the first flow rate measurement section measures the flow rate, the second calculation section calculates the flow rate, and the second flow rate control section controls the flow rate so that the flow rate is constant. In this way, since the first pressure control device or the first flow rate control device is provided on the carrier gas inflow side or the outflow side of the bubbler, by operating these devices simultaneously, the pressure and volume of the carrier gas are kept constant, and the raw material supply is controlled. Fluctuations in the concentration of the supply source in the line can be eliminated, and source gas at a constant concentration can always be supplied. Furthermore, by providing the second flow rate wII11 section on the downstream side of the first flow rate measurement section, the first flow rate measurement section is not affected by the pressure of the gas line downstream of the second flow rate control section.

Semiconductor manufacturing bag according to claim (2)! According to the second pressure control device and the second flow rate side? Since the I device can measure temperature, pressure and flow rate simultaneously,
Allows calculation of molar flow rate. In addition, the molar flow rate of the source is calculated backwards by adding correction terms such as gas temperature difference to the difference between the mixed gas flow rate measured at the gas outflow side of the bubbler and the carrier gas flow rate measured at the gas inflow side of the bubbler. This makes it possible to always supply a mixed gas at the desired molar flow rate. Furthermore, by monitoring the molar flow rate of the mixed gas source using the display unit, it becomes possible to predict the exchange magnetism to the bong. Furthermore, since the flow rate measurement section was provided upstream of the flow rate control section, the flow rate measurement section was not affected by the pressure downstream of the flow rate control section, and since the temperature measurement section was provided upstream of the flow rate measurement section, the flow rate measurement section It is possible to eliminate the effects of heater heating and adiabatic expansion/contraction of gas in the flow rate control section.

Furthermore, a pressure measurement section, a flow measurement section, and a temperature measurement section.

By integrating the arithmetic unit and the flow rate control unit, in addition to measuring the molar flow rate δM of the source, it is possible to downsize the device, stabilize the control, and simplify the piping.

〔Example〕

A first embodiment of this invention will be explained with reference to FIG. That is, FIG. 1 shows a semiconductor manufacturing apparatus having a control device in a raw material supply line for eliminating fluctuations in supply source concentration. This device includes a carrier gas line 11, a first pressure control device 12a which is a constant pressure mass flow, and a source 13.
, a bubbler 14 for sauce supply, a first flow rate control device 15a which is a constant mass flow, a constant temperature bath 16, a main gas line 17, a changeover switch (pulp) 19, and a vent gas line 20.

The carrier gas line 11 is a line that supplies a carrier gas that carries source vapor, and is mostly a hydrogen gas or nitrogen gas line. This carrier gas line 11
The pressure is controlled by the first pressure control device 12 using a regulator or the like.
It is necessary to control the pressure to be higher than the pressure controlled by a.

The first pressure control unit f12a controls the pressure inside the bubbler 14 to be constant. This first pressure control device 12 includes a first pressure measuring section 2a and a first calculating section 7a which receives the measured value of the first pressure measuring section 2a as an input signal.
and a first flow rate control section 8a that responds to the output signal of the first calculation section 7a. First pressure measuring section 2a
It is similar to a Halatron pressure gauge, for example, and is made of a diaphragm gauge and outputs the measured pressure as a voltage.

The first flow rate control section 8a has a structure that automatically opens and closes a needle valve. Further, the first calculation section 7a compares the set pressure value and the actual measured value and outputs an output to control the first flow rate control section 8a so that the difference becomes zero.

The control pressure controlled by the first pressure control device 12a is mostly 760 Hg. Variations in the pressure control of the first pressure control device 12 directly affect fluctuations in the concentration of the supply source, so extremely high precision pressure control is required.

The source 13 supplies a constituent gas or doping gas in MOVPE growth, etc., and is usually made of solid or liquid. The bubbler 14 is a container for efficiently vaporizing the source 13 into gas. A constant temperature bath 16 controls the temperature of the bubbler 14.

The first flow rate control device 15a supplies a constant flow rate of the mixed gas in which a constant amount of the source 13 has been dissolved. The first flow rate control device 15a includes a first flow rate measuring section 3a and a second flow rate measuring section 3a which receives the measured value of the first flow rate measuring section 3a as an input signal.
a calculation section 7b, and a second calculation section 7b located downstream of the first flow rate measurement section 3a and responsive to the output signal of the second calculation section 7b.
A flow rate control section 8b is provided. First flow rate measuring section 3
A is regarded as the movement of heat flowing through the capillary tube, and the amount of heat movement is converted into voltage and output. 18 is a heater that heats gas through a capillary tube. The first flow rate measurement section 3a is provided upstream of the second flow rate control section 8b so as not to be affected by pressure fluctuations in the gas line downstream of the second flow rate control section 8b. The second calculation section 7b compares the set value of the flow rate and the actual measured value and outputs the result to the second flow rate control section 8b so that the difference becomes zero. Further, the first flow rate control device 15a generates pressure for the first pressure control device 12a and suppresses pressure fluctuations in the bubbler 14 due to pressure fluctuations in the main gas line 17.

Switching between the main gas line I7 and the vent gas line 20 by the changeover switch 19 is the same as that shown in FIG.

According to this embodiment, the first pressure measuring section 2a measures the pressure on the upstream side of the bubbler 14 for supplying source gas, and the first
The first
The flow rate is controlled by a flow rate control section 8a. Further, the flow rate is measured by the first flow rate measurement section 3a, and the flow rate is controlled by the second flow rate control section 8b so that the flow rate is compensated for by the second compensating section 7b and the flow rate is constant.

In this way, since the first pressure control device f12a and the first flow rate control device 15a are provided on the carrier gas inflow side and outflow side of the bubbler 14, the flow rate of the carrier gas is kept constant and the pressure inside the bubbler is kept constant. As a result, the source gas can always be supplied at a constant concentration.

As a result, according to equation (1), by keeping the pressure PB in the bubbler 14 and the carrier gas flow rate F constant, it is possible to eliminate fluctuations in the molar flow rate M of the mixed gas, and it is possible to always maintain a stable molar flow rate of the mixed gas. In order to be able to supply
Multicomponent systems, such as 1nGaAsP/InP, AlGaAs
/GaAs, AlGa1nP/Ga1nP, etc., with different compositions, especially MOV
PE (organic metal vapor phase epitaxy) growth can be achieved continuously and with good reproducibility.

Also, as shown in Figure 2, the experimental results show that the first pressure system?
It can be seen that by simultaneously automatically controlling the No. 11 device 12a and the first flow rate control device 15a, fluctuations in source pressure at the time of gas switching are suppressed. That is, Pl
is the flow rate in the case of the conventional example, and when the changeover switch is used to switch from the vent gas line 20 to the main gas line I7 from time T1 to T2, the flow rate fluctuates at each time T, T2. P2 is the flow rate in this example, and there is no change at time T, . . . T2. Q is the pressure of the main gas line 17, and Q2 is the pressure of the vent gas line 20.

Furthermore, the second flow rate control section 8b is connected to the first flow rate measurement section 3a.
By providing it downstream of the second flow rate control section 8a, it is possible to prevent the influence of the pressure of the gas line downstream of the second flow rate control section 8a.

Further, in this embodiment, the first flow rate control section 8a and the first
Since a pressure valve with a large galvanometric area, such as a needle valve, is used in the flow rate control unit 8b of the first flow rate control unit 15, gas pressure can be controlled and gas backflow can be suppressed.
It is possible to prevent fluctuations in the pressure on the gas inflow side of the first flow rate control device 15a from occurring due to fluctuations in the pressure on the gas outflow side of the first flow rate control device 15a.

Therefore, this embodiment is a semiconductor manufacturing equipment that has a 'f11m device that can independently control pressure and flow rate and controls the pressure and flow rate to a constant value, and uses seven sources of liquid or solid source. Alternatively, it can be applied as a source supply piping system to control fluctuations in source concentration in a raw material supply line using sublimation.

Note that a first pressure control device 12a is installed on the gas inflow side of the bubbler 14, and a first flow rate control device 12a is installed on the gas outflow side. 11 device 15a is installed, but conversely, the first flow rate control device 15a may be installed on the gas inflow side, and the first pressure control device 12a may be installed on the gas outflow side.

In this case, the first pressure measurement section 2a of the first pressure control device 12a needs to be installed on the bubbler 14 side of the first flow rate control section 8a with respect to the gas flow.

Further, although the pressure measuring section 2 is a diaphragm gauge, other pressure gauges may be used, and although the setting position is set at the last stage of the gas flow, it may be located anywhere.

Further, although the first flow rate measuring section 3a is based on heat transfer in a capillary tube, other measuring means may be used. Further, a first flow rate 1tIIIl11 section 8a and a second flow rate control section 8b
Although needle pulp is used, other flow rate control devices having a pressure control function may be used as long as the galvanic area is large.

A second embodiment of the invention will be explained with reference to FIGS. 3 and 4. In other words, Fig. 3 shows the raw material supply line,
FIG. 2 is a configuration diagram of a source supply piping system of a semiconductor manufacturing apparatus that measures the molar flow rate of a source gas and supplies the source gas at a predetermined constant molar flow rate. In this figure, carrier gas line 11, source 13, bubbler 14
, a constant temperature bath 16, a main gas line 17, a gas line 20, and a changeover switch 19 are the same as those in the first embodiment.

The second pressure control device 12b controls the pressure inside the bubbler 14 to be constant as in the first embodiment, and includes a first temperature measuring section 4a and a first temperature measuring section 4a.
a second flow rate measurement section 3b located downstream of the second flow rate measurement section 3b; and a third flow rate control section 8C located downstream of the second flow rate measurement section 3b.
a second pressure measuring section 2b, the first temperature measuring section 4a,
The third flow rate control unit 8 uses the measured values of the second flow rate measurement unit 3b and the second pressure measurement unit 2b as input signals.
A third arithmetic unit 7C that provides an output signal to C is provided.

The second pressure measuring section 2b and the second flow rate measuring section 3b are the same as those in the first embodiment. The first temperature measuring section 4a measures the temperature of the gas and outputs it as a voltage. Further, the third calculation unit 7c compares the set pressure value and the actual measured value and outputs the difference to be O to the third flow rate control unit 8c. In this case, if the measured pressure is smaller than the set pressure, the flow rate is increased.

Variations in the pressure control of the second pressure control device 12b directly affect the fluctuations in the molar flow rate of the source of the supply gas, so extremely high precision pressure control is required as in the first embodiment6. Further, the flow rate of the carrier gas is also measured by the second flow rate measurement unit 3b in the second pressure control bag f12b, and the measured flow rate of the carrier gas is transferred to the fifth calculation unit 28 that calculates the concentration of the source gas. is input.

The second flow rate control device 15b controls to supply a constant flow rate of the mixed gas in which a constant amount of sauce has been dissolved. This second flow control section! 15b is a second temperature measuring section 4b, a third flow rate measuring section 3C located downstream of this second temperature measuring section 4b, and a fourth flow rate measuring section 3C located downstream of this third flow rate measuring section 3C. The measurement values of the control unit 8d, the third pressure measurement unit 2C, the second temperature measurement unit 4b, the third flow rate measurement unit 3C, and the third pressure measurement unit 2C are input signals, and the A fourth calculation section 7d that provides an output signal to the fourth flow rate control section 8d is provided.

The fourth calculation section 7d compares the set value of the flow rate with the actual measured value and outputs the difference to be O to the fourth flow rate control section 8d. In this case, when the actual measured value is smaller than the set value, the flow rate is increased.

Similarly to the first embodiment, the second flow rate control device 15b generates pressure for the second pressure control device 12b, and also controls the pressure in the source supply bubbler 14 due to pressure fluctuations in the main gas line 17. suppress fluctuations in

The fifth calculation unit 28 operates between the second pressure control device 12b and the second pressure control device 12b.
The molar flow rate of the source is calculated from the difference in the flow rate of the fluid flowing between the flow rate control device 15b and the flow rate control device 15b. The fifth calculation unit 28 receives the signals from the second flow rate measurement unit 3b and the third pressure measurement unit 2C, and receives the mixed gas flow rate set by the second flow rate control device 15b on the gas outflow side of the bubbler 14. and Bubbler 1
By adding a correction term such as a gas temperature difference to the difference in carrier gas flow rate measured by the second pressure control device 12b on the gas inflow side of No. 4, the source molar flow rate at that time is calculated from equation (1). If there is a difference between the set source molar flow rate and the actual source molar flow rate, the second flow rate controller 15b is controlled to change the mixed gas flow rate so that the difference is reduced to O. The mixed gas is supplied so that the molar flow rate of the source gas flowing through the line 17 takes a constant value.

The display unit 6 displays actually measured values such as flow rate and pressure, and calculation results.

Note that the setting unit 5 is provided in the second pressure control device 12b and the second flow rate control device 15b, and outputs a voltage corresponding to a set value of the flow rate or pressure.

According to this embodiment, the pressure, temperature, and flow rate can be measured simultaneously by the second flow rate control device 15b, making it possible to calculate the molar flow rate. That is, by simultaneously measuring the temperature, flow rate, and pressure of the gas at the same point, the molar flow rate δM of the source can be calculated from the following equation (21).

P・δF=σMRT (2) Here, P is the gas pressure, and δF is the gas flow rate change due to the melting of the source! , δM is the molar flow rate of the dissolved sauce,
R is the gas constant and T is the temperature of the gas.

In addition, by adding correction terms such as gas temperature difference to the difference between the flow rate of the mixed gas measured at the gas outflow side of the bubbler 14 and the flow rate of the carrier gas measured at the gas inflow side of the bubbler 14, the molar flow rate of the source can be calculated. This makes it possible to move the mixed gas at the desired molar flow rate at all times.

Furthermore, by monitoring the molar flow rate of the mixed gas source using the display unit 6, it becomes possible to predict when to replace the source cylinder.

Furthermore, since the first temperature measurement section 4a is provided at the forefront of the gas inflow section, the influence of heater heating in the second flow rate measurement section 3b and the influence of adiabatic expansion and contraction of the gas in the second flow rate control section 3b are eliminated. can do.

In addition, the flow rate measurement unit (3b, 3C) includes a flow rate control unit (8c,
8d) is provided on the previous stage side of the flow rate control section (8c, 8d) so as not to be affected by the pressure of the gas line on the latter stage side. Therefore, the equipment arrangement is a temperature measurement section (4a4b), a flow rate measurement section (3b, 3c), and a flow rate control section (8c, 8d).

Furthermore, the pressure measuring section (2b, 2C) and the flow rate measuring section (3b
, 3c), temperature measurement section (4a, 4b), calculation section (7c,
By integrating 7d) and the flow rate control unit (8C98d), the molar flow rate δM of the source can be measured using equation (2), and the device can be made smaller and the control more stable. Simplification becomes possible.

Furthermore, assuming that the molar flow rate δM of the source obtained here is M', equation (3) is used for the set molar flow rate M of the source.
The source gas flow rate F' can be adjusted so that a constant molar flow rate of the mixed gas always flows in the main gas line 17.

F' = F x M/M'...
...131 Here, F' is the newly set flow rate of the mixed gas, F is the flow rate of the mixed gas before setting, M is the set value of the molar flow rate, and M' is the actual value of the molar flow rate.

As a result, it is possible to always supply a mixed gas with a stable molar flow rate.
/InP, , A1GaAs/GaAs.

In epitaxial growth of different compositions such as AlGa InP/Ga InP, especially in MOVPE growth, the epitaxial growth conditions can be controlled as a function of the source supply amount, making it possible to always perform epitaxial growth under constant conditions even during long-term use.

In the second embodiment, the second pressure control device 12b was installed on the inflow side of the bubbler 14, and the second flow rate control device 15b was installed on the outflow side. The control device 15b may be installed, and the second pressure control device 12b may be installed on the outflow side. In this case, the second pressure measurement section 2b of the second pressure control device 12b needs to be installed on the bubbler 14 side of the third flow rate control section 8c with respect to the gas flow, and the second pressure measurement section 2b of the second pressure control device 12b needs to be installed on the bubbler 14 side of the third flow rate control section 8c. The third pressure measuring section 2C of 15b controls the fourth flow rate control section 8 for the gas flow.
It is necessary to install it on the bubbler 14 side of d.

Although FIG. 4 shows the configuration of the second pressure control device 12b, the same configuration can be used in common with the second flow rate control device 15b by changing the connection order of internal devices. Further, by simply stopping the functions of the first temperature measuring section 43 and the like, it can be used in common as the first pressure control device and the first flow rate control device of the first embodiment. In this case, the setting unit 5 not only sets the flow rate and pressure, but also determines whether the mass flow controller is used as a constant pressure mass flow or a constant flow mass flow, and if the molar flow rate is to be constant, the calculation result is input externally. A usage changeover switch is provided to determine whether to use the external input section for input.

Furthermore, a first pressure control device 12a and a second pressure control device i
An alarm circuit may be provided in consideration of the case where the set pressure is not reached even if the flow rate is maximized during control of the il device f12b.

〔Effect of the invention〕

In the semiconductor device of claim (1), the first pressure control is provided on the carrier gas inflow side or the outflow side of the bubbler. Since the IIl device or the first flow rate control device is installed, by operating these devices simultaneously, the pressure and volume of the carrier gas are kept constant, eliminating fluctuations in the concentration of the supply source in the raw material supply line, and ensuring that the source gas always has a constant concentration. can be supplied. Furthermore, by providing the second flow rate control section downstream of the first flow rate measurement section, the first flow rate measurement section is not affected by the pressure of the gas line downstream of the second flow rate control section. There is.

In the semiconductor manufacturing apparatus according to claim (2), since the second pressure control device and the second flow rate control device can measure temperature, pressure, and flow rate simultaneously, it is possible to measure the molar flow rate. In addition, the molar flow rate of the source is calculated backwards by adding correction terms such as gas temperature difference to the difference between the mixed gas flow rate measured at the gas outflow side of the bubbler and the carrier gas flow rate measured at the gas inflow side of the bubbler. This makes it possible to always supply a mixed gas at the desired molar flow rate. Furthermore, by monitoring the molar flow rate of the mixed gas source using the display unit, it becomes possible to predict the exchange magnetism of the cylinder.

Furthermore, since the flow rate measurement unit was installed upstream of the flow rate control unit,
The flow measurement section is not affected by the pressure downstream of the flow control section, and the temperature measurement section is provided upstream of the flow measurement section, so there is no effect of heater heating in the flow measurement section or adiabatic expansion of gas in the flow control section. The influence of adiabatic contraction can be eliminated. Furthermore, a pressure measurement section, a flow measurement section, a temperature measurement section,
By integrating the arithmetic unit and the flow rate control unit, it is possible to measure the molar flow rate δM of the source, downsize the device, stabilize control, and simplify piping.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a raw material supply line according to a first embodiment of the present invention, FIG. 2 is a diagram showing the relationship between mass flow rate and gas line pressure with respect to time, and FIG. 3 is a diagram showing a raw material supply line according to a second embodiment of the present invention. A line configuration diagram, FIG. 4 is an explanatory diagram for explaining the pressure control device and the flow rate control device, FIG. 5 is an explanatory diagram for explaining the first conventional example, and FIG. 6 is an explanatory diagram for explaining the second conventional example. FIG. 7 is a diagram showing the relationship between the amount of organometallic gas used and the degree of saturation of organometallic gas. 2a...First pressure measurement section, 3a...First flow rate measurement section, 7a...First calculation section, 7b...Second calculation section, 8a...First flow rate Control unit, 8b... second flow rate control unit, 12a... first pressure control device, 14...
・Bubbler 15a...first flow rate control device%,
＼ctdQ ward C faction t＞K draw q generation- Rei ward taste

Claims (2)

[Claims] (1) A first pressure measurement section, a first calculation section that receives the measured value of the first pressure measurement section as an input signal, and a first flow control that responds to the output signal of the first calculation section. a first pressure control device having a first flow rate measurement unit; a second calculation unit that receives the measured value of the first flow rate measurement unit as an input signal; and the first flow rate measurement unit. and a second flow rate control section that is located downstream of and responds to the output signal of the second calculation section, the first pressure control device and the first flow rate control section. One of the flow rate control devices is disposed upstream of a bubbler for supplying source gas, and the other is disposed downstream of the bubbler, and the first pressure measuring section of the first pressure control device is configured to control the first flow rate. A semiconductor manufacturing apparatus located on the bubbler side with respect to the part. (2) a first temperature measurement section, a second flow rate measurement section downstream of the first temperature measurement section, and a third flow rate control section downstream of the second flow rate measurement section; , the measured values of the second pressure measuring section, the first temperature measuring section, the second flow rate measuring section and the second pressure measuring section are used as input signals, and an output signal is sent to the third flow rate control section. a second pressure control device provided with a third calculation section that gives a second temperature measurement section; a fourth flow rate control section located downstream of the flow rate measurement section, a third pressure measurement section, the second temperature measurement section, the third flow rate measurement section, and the third pressure measurement section; a second flow rate control device including a fourth calculation section that takes a measured value as an input signal and provides an output signal to the fourth flow rate control section; the second pressure control device; and the second flow rate control device. a fifth calculation unit that calculates the molar flow rate of the source from the difference in the flow rate of the fluid flowing between the second pressure control device and the second flow rate; and a display unit that displays the measured value and the calculation result. One of the control devices is disposed on the upstream side of a bubbler for supplying source gas, and the other is disposed on the downstream side, and the second pressure measurement section is disposed on the bubbler side with respect to the third flow rate control section. Further, the third pressure measurement section is located on the bubbler side with respect to the fourth flow rate control section, and the fifth pressure measurement section is located on the bubbler side with respect to the fourth flow rate control section.
A semiconductor manufacturing apparatus characterized in that the second flow rate control device is controlled by the output signal of the calculation section.