Raw material gas supply apparatus for semiconductor manufacturing equipment

Abstract

A raw material gas supply apparatus includes a liquid raw material gas supply source, a source tank storing liquid raw material, a gas distribution passage through which raw material gas comprising steam of the liquid raw material is supplied to a process chamber from the source tank, an automatic pressure regulator installed on an upstream side of the gas passage, wherein the automatic pressure regulator keeps supply pressure of the raw material gas at a set value, a supply gas switching valve installed on a downstream side of the gas passage, wherein this valve opens and closes the gas passage, an orifice provided on at least one of an inlet side or outlet side of the valve, wherein the orifice regulates flow rate of the raw material gas, and a constant temperature heating device heats the source tank, the gas passage, the valve and the orifice to a set temperature.

Claims

1. A raw material gas supply apparatus for semiconductor manufacturing equipment comprising: (a) a liquid raw material supply source; (b) a source tank that stores liquid raw material supplied by the liquid raw material supply source through a liquid raw material flow rate meter and a liquid raw material supply valve; (c) a first gas distribution passage through which a raw material gas passes to a process chamber, wherein the raw material gas is steam of the liquid raw material that is supplied from an internal upper space portion of the source tank; (d) an automatic pressure regulator installed on an upstream side of the first gas distribution passage, wherein the automatic pressure regulator keeps a supply pressure of the raw material gas that is supplied to the process chamber at a set pressure value, wherein the automatic pressure regulator comprising, i. a control valve; ii. a gas pressure detector and a gas temperature detector provided on the downstream side of the control valve; iii. a temperature correction circuit to correct detected gas pressure; iv. an input-output circuit of a set pressure; v. a comparison circuit comparing a temperature-corrected detection pressure from the temperature correction circuit and the set pressure from the input-output circuit; and vi. an output circuit that output a control signal proportional to a difference between the temperature-corrected detection pressure and the set pressure to the control valve; (e) a supply gas switching valve installed near the process chamber on a downstream side of the first gas distribution passage, wherein the supply gas switching valve opens the first gas distribution passage for a certain period of time so as to supply a set flow rate of the raw material gas to the process chamber; (f) a throttling unit provided on an inlet side of the supply gas switching valve, wherein the throttling unit regulates a flow rate of the raw material gas that is supplied to the process chamber to a predetermined flow rate value which is proportional to the set pressure; (g) a constant temperature heating device that heats the source tank, the first gas distribution passage, the supply gas switching valve and the throttling unit to a set temperature; and (h) a plurality of gas distribution passages for a plurality of different raw material gases provided in parallel to and independently from the first gas distribution passage for the raw material gas and supplying a set flow rate of desired different raw material gases separately to the process chamber, wherein each of the plurality of gas distribution passages is provided with a gas tank storing a desired different raw material gas, an automatic pressure regulator, a gas supply passage between the tank storing desired different raw material gas and the automatic pressure regulator, a throttling unit, a supply gas switching valve and a constant temperature heating device, wherein the raw material gas and the different raw material gases at the set flow rate are supplied to the process chamber separately through the each opened supply gas switching valve, while the supply pressures of the raw material gas in the first gas distribution passage and the different raw material gases in the plurality of gas distribution passages between a downstream side of the control valve of the automatic pressure regulator and the throttling unit are controlled to desired pressures by the automatic pressure regulators provided on the first gas distribution passage for the raw material gas and the plurality of gas distribution passages for different raw material gases; wherein the raw material gas that is supplied to the process chamber is supplied to the process chamber without a carrier gas.

2. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 1, wherein the raw material gas is titanium tetrachloride (TiCl.sub.4).

3. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 1, wherein the throttling unit is provided on the inlet side of the supply gas switching valve.

4. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 1, wherein the source tank is heated to a temperature of 100 C. to 250 C. by the constant temperature heating device.

5. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 1, wherein the first gas distribution passage, the automatic pressure regulator, the throttling unit and the switching valve are heated to a temperature of 100 C. to 250 C. by the constant temperature heating device.

6. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 1, wherein argon gas is supplied to the process chamber through a second gas distribution passage of the plurality of gas distribution passages, wherein ammonia gas is supplied to the process chamber through a third gas distribution passage of the plurality of gas distribution passages, and wherein the second and third gas distribution passages are respectively provided in parallel to the first gas distribution passage.

7. The raw material gas supply apparatus for semiconductor manufacturing equipment according to claim 6, wherein the throttling unit comprises a plurality of orifices, wherein each of the first gas distribution passage, the second gas distribution passage and the third gas distribution passage is provided with one orifice of the plurality of orifices.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a systematic schematic diagram showing a configuration of a raw material gas supply apparatus according to an embodiment of the present invention.

(2) FIG. 2 is an explanatory diagram of a configuration of an automatic pressure regulating device employed by the present invention, namely, automatic pressure regulator 6G.sub.1.

(3) FIG. 3 shows an example of pressure, temperature, flow rate, and the like, of a raw material gas supply line according to an embodiment of the present invention.

(4) FIG. 4 is a systematic schematic diagram showing a configuration of a conventional raw material gas supply apparatus.

(5) FIG. 5 is a systematic schematic diagram showing a configuration of another conventional raw material gas supply apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a systematic diagram showing a configuration of a raw material gas supply apparatus according to an embodiment of the present invention. The raw material gas supply apparatus is composed of a liquid raw material tank 1, a liquid raw material flow rate meter 2, a liquid raw material supply valve 3, a liquid raw material gas 4, a source tank 5, a raw material gas outlet valve 7, an automatic pressure regulating device 6 that controls internal pressure of distribution passages 9 for the raw material gas supplied to a process chamber 11, a throttling unit 8 (here, orifices 8G.sub.1, 8G.sub.2, 8G.sub.3 and 8G.sub.n are used) that regulates a flow rate of supplying a gas G that is supplied to the process chamber 11, the gas distribution passages 9, supply gas switching valves 10, a constant temperature heating device 15 that heats the gas distribution passages 9, the source tank 5, and the like.

(7) In addition, in FIG. 1, in addition to the liquid raw material tank 1, an ammonia gas tank 1G.sub.2, an argon gas tank 1G.sub.3 and another gas tank 1G.sub.n, are provided, and automatic pressure regulators 6G.sub.2, 6G.sub.3 and 6G.sub.n, orifices 8G.sub.2, 8G.sub.3 and 8G.sub.n, and supply switching valves 10G.sub.2, 10G.sub.3 and 10G.sub.n are respectively provided to the respective gas distribution passages 9G.sub.2, 9G.sub.3 and 9G.sub.n, and raw material gases G.sub.1, G.sub.2, G.sub.3 and G.sub.n are respectively supplied to the process chamber 11.

(8) With reference to FIG. 1, the liquid raw material gas 4 is supplied from the liquid raw material tank 1 through the flow rate meter 2 and the liquid raw material supply valve 3, to the inside of the source tank 5, and is heated to a predetermined temperature by the constant temperature heating device 15, to be stored in the source tank in a heated state. In addition, since titanium tetrachloride (TiCl.sub.4) is used as one of the liquid raw material gases in the present embodiment, the liquid raw material gas 4 will hereinafter be described as TiCl.sub.4.

(9) With respect to the liquid raw material gas 4 in the source tank 5, by heating the source tank 5 to about 100 C. to 110 C., steam G.sub.1 at a saturated steam pressure (for example, at 100 C. and 269 Torr) of the liquid raw material gas 4 at its heated temperature is generated, so as to fill the inside of an internal upper space portion 5a of the source tank 5. The generated saturated steam G.sub.1 of the liquid raw material gas 4 flows through the raw material gas outlet valve 7, into an automatic pressure regulator 6G.sub.1, and is regulated to a predetermined set pressure by the automatic pressure regulator 6G.sub.1, and is supplied through the orifice 8G.sub.1 and the raw material gas supply switching valve 10G.sub.1, into the process chamber 11.

(10) The aforementioned automatic pressure regulator 6G.sub.1 is provided near the outlet side of the raw material gas G.sub.1 from the source tank 5. The automatic pressure regulator 6G.sub.1 is for automatically regulating the pressure on the secondary side (i.e., downstream side) of the automatic pressure regulator 6G.sub.1 of the raw material gas G.sub.1 from the source tank 5 to a predetermined set value. That is, as shown in FIG. 2, the aforementioned automatic pressure regulator 6G.sub.1 detects a pressure P.sub.1 and a temperature T.sub.1 of the raw material gas G.sub.1 on the outflow side of the automatic pressure regulator 6G.sub.1, and carries out a temperature correction in an arithmetic and control unit 12 by use of the detected pressure P.sub.1 and the temperature T.sub.1, thereby carrying out an operation for correcting detected pressure to the actual pressure of the high-temperature mixed gas G.sub.1, and moreover, the arithmetic and control unit 12 compares the computed pressure value Pt of the raw material gas G.sub.1 and a set pressure value Ps from a set input terminal 13, to control the opening or closing of a control valve V.sub.0 in a direction in which a deviation Pd between both the set pressure value Ps and the computed pressure value Pt becomes zero.

(11) In addition, FIG. 2 shows a block configuration of the automatic pressure regulator 6G.sub.1, and the arithmetic and control unit 12 of automatic pressure regulator 6G.sub.1, which is composed of a temperature correction circuit 12a, a comparison circuit 12b, an input-output circuit 12c, an output circuit 12d, and the like. That is, the detection values from a pressure detector P.sub.1 and a temperature detector T.sub.1 are converted into digital signals, to be input to the temperature correction circuit 12a, and the detection pressure P.sub.1 is corrected to a detection pressure Pt therein, to be thereafter input to the comparison circuit 12b. Furthermore, an input signal Ps of the set pressure is input from the terminal 13, to be converted into a digital value in the input-output circuit 12c, and is thereafter input to the comparison circuit 12b. In the case where the set pressure input signal Ps is higher than the temperature-corrected detection pressure Pt from the temperature correction circuit 12a, a control signal Pd is output to the drive unit of the control valve V.sub.0. As a result, the control valve V.sub.0 is driven toward the valve-closing direction, so as to be driven toward the valve-closing direction until a difference signal Pd=PsPt between the set pressure input signal Ps and the temperature-corrected detection pressure Pt becomes zero.

(12) Furthermore, in contrast, in the case where the set pressure input signal Ps is lower than the temperature-corrected detection pressure Pt, a control signal Pd is output to the drive unit of the control valve V.sub.0, and the control valve V.sub.0 is driven toward the valve-opening direction. As a result, the control valve V.sub.0 is driven toward the valve-opening direction, and the arithmetic and control unit 12 continues to send a difference signal Pd to the drive unit of the control valve V.sub.0 that drives the control valve V.sub.0 toward the valve-opening direction until the difference signal Pd=PsPt becomes zero.

(13) As shown in FIG. 1, the raw material gas G.sub.1, whose gas pressure on the secondary side is kept at the set pressure by the automatic pressure regulator 6G.sub.1, is supplied through the supply gas switching valve 10G.sub.1 to the process chamber 11 at a predetermined flow rate corresponding to the set pressure of the raw material gas G.sub.1 at the orifice 8G.sub.1, and corresponding to a caliber of the orifice 8G.sub.1 and a gas temperature of the raw material gas G.sub.1.

(14) In addition, the above description describes only the line corresponding to the gas distribution passage 9G.sub.1 for the raw material gas G.sub.1. However, the other lines, such as correspond to the gas distribution passage 9G.sub.2 and the gas distribution passage 9G.sub.3 as well, etc., are completely structurally the same as the case of the gas distribution passage 9G.sub.1 except for the portion that connects to the source tank 5.

(15) Furthermore, the orifices 8 (8G.sub.1, 8G.sub.2, 8G.sub.3, 8G.sub.n) are provided on the upstream side of the supply gas switching valves 10 (10G.sub.1, 10G.sub.2, 10G.sub.3, 10G.sub.n) in the above-described description. However, the orifices 8 (8G.sub.1, 8G.sub.2, 8G.sub.3, 8G.sub.n) may be provided on the downstream side of the supply gas switching valves 10 (10G.sub.1, 10G.sub.2, 10G.sub.3, 10G.sub.n), or they may be provided both on the upstream side and the downstream side.

(16) Moreover, in the above-non-limiting embodiment, titanium tetrachloride is used as the liquid raw material gas. However, as a matter of course, a different liquid raw material may be used as the liquid raw material gas, such as TEOS (Tetraethyl Orthosilicate), for example. However, the heating temperature for the source tank 5, the gas distribution passages 9 (9G.sub.1, 9G.sub.2, 19G.sub.3, 9G.sub.n) and the supply gas switching valves 10 (10G.sub.1, 10G.sub.2, 10G.sub.3, 10G.sub.n) by the constant temperature heating device 15 is appropriately selected according to the saturated steam pressure of the particular liquid raw material gas that is used, and the required flow rate and pressure likewise must be appropriately selected depending upon the particular raw material gas that is used.

(17) In accordance with the present invention, the pressure and the temperature of the raw material gas on the secondary side of the automatic pressure regulating device 6 are kept at set values by the automatic pressure regulating device 6, and the flow rate of the raw material gas is regulated via the orifices 8. Therefore, there is absolutely no need to perform aperture control of the supply gas switching valves 10 for regulating a flow rate, as in the conventional techniques, and it suffices to merely switch among supply gases. Accordingly, it is possible to perform more highly accurate flow control when employing a raw material gas by itself, or when employing the raw material gas to a process chamber 11 in combination with other gases.

(18) Furthermore, in accordance with the present invention, it is possible to directly supply only a required raw material gas to the process chamber 11 under highly accurate flow control, which makes it possible to make the raw gas distribution passages 9, and the like, smaller in calibers and a simplification thereof can be made, and there is no need to manage the concentration of the raw material gas.

(19) FIG. 3 shows the relationship among the pressure, temperature, flow rate, and the like, of the gas distribution passage 9G.sub.1, which includes the automatic pressure regulator 6G.sub.1 in the case where the raw material gas is TiCl.sub.4, and the flow rate of the TiCl.sub.4 gas is 10 sccm. It has been confirmed by the inventors that it is possible to supply the TiCl.sub.4 gas at 10 sccm under the conditions that the source tank temperature=100 C., the TiCl.sub.4 gas pressure in the source tank internal space 5a=269 Torr (100 C.), the pressure P.sub.1 on the upstream side of the automatic pressure regulator 6G.sub.1=269 Torr, the pressure P.sub.2 on the downstream side of the automatic pressure regulator 6G.sub.1=200 Torr, and the caliber of the orifice 8G.sub.1 is 0.1 mm. In addition, a distance L.sub.2 between the orifice 8G.sub.1 and the supply gas switching valve 10G.sub.1 is set to 10 mm or less, and a distance L.sub.1 between the automatic pressure regulator 6G.sub.1 and the orifice 8G.sub.1 is set to about 2 m.

(20) In addition, because the flow rate of the TiCl.sub.4 gas is a function of temperature, it is possible to regulate the flow rate of such a raw material gas G.sub.1 by regulating the control pressure P.sub.2 on the secondary side of the automatic pressure regulator 6G.sub.1.

(21) The NH.sub.3 gas distribution passage 9G.sub.2 as well, in the case where NH.sub.3 gas G.sub.2=10 SLM, has been reviewed by the same method. As a result of this review, it was found that when the control pressure P.sub.2 of the automatic pressure regulator 6G.sub.2=790 Torr, and the temperature is 23 C., and the caliber of the orifice 8G.sub.2=1.0 mm, it is possible to supply the NH.sub.3 raw material gas G.sub.2 at a flow rate of about 10 SLM (when the pressure on the downstream of the orifice satisfies the critical expansion conditions with respect to P.sub.2).

(22) Furthermore, with respect to the Ar gas distribution passage 9G.sub.2 as well, when the control pressure P.sub.2 of the automatic pressure regulator 6G.sub.3=100 Torr, and the temperature is 23 C., and the caliber of the orifice 8G.sub.3=1.0 mm, it is possible to supply the Ar gas G.sub.3 at a flow rate of about 10 SLM (when the pressure on the downstream of the orifice satisfies the critical expansion conditions with respect to P.sub.2).

INDUSTRIAL APPLICABILITY

(23) The present invention is applicable not only to a raw material vaporizing and supplying apparatus used for an ALD method, for example, but it is also applicable to all the gas supply apparatuses that are configured to supply gas from a pressurizing reservoir source to a process chamber in semiconductor manufacturing equipment, chemical products manufacturing equipment, or the like. Thus, in accordance with the present invention, it is possible to stably supply only a raw material gas, which is a steam of a liquid raw material gas, to a process chamber without using a carrier gas while controlling the flow rate of the raw material gas in a highly accurate manner, and it is also possible to simplify and downsize the structure of a raw material gas supply apparatus that is used to supply the raw material gas.

(24) Broadly construed, the present invention pertains to a raw material gas supply apparatus that includes (a) a liquid raw material supply source, (b) a source tank in which the liquid raw material is stored, (c) a gas distribution passage through which a raw material gas, which is a steam of the liquid raw material, is supplied from an internal upper space portion of the source tank to a process chamber, (d) an automatic pressure regulator that is installed on an upstream side of the gas distribution passage, wherein the automatic pressure regulator keeps supply pressure of the raw material gas that is supplied to the process chamber at a set value, (e) a supply gas switching valve that is installed on a downstream side of the gas distribution passage, wherein the supply gas switching valve opens and closes the passage for the raw material gas that is supplied to the process chamber, (f) an orifice that is provided on at least one of an inlet side or an outlet side of the supply gas switching valve, wherein the orifice regulates the flow rate of the raw material gas supplied to the process chamber, and (g) a constant temperature heating device that heats the source tank, the gas distribution passage, the supply gas switching valve and the orifice to a set temperature, and wherein the raw material gas at a set flow rate is supplied to the process chamber while controlling supply pressure of the raw material gas on a downstream side of the automatic pressure regulator to be a desired pressure.

DESCRIPTION OF REFERENCE SYMBOLS

(25) G.sub.1: Raw material gas

(26) G.sub.2: Ammonia gas

(27) G.sub.3: Argon gas

(28) G.sub.n: Another gas

(29) 1: Liquid raw material gas tank (titanium tetrachloride)

(30) 1G.sub.2: Ammonia gas tank

(31) 1G.sub.3: Argon gas tank

(32) 1G.sub.n: Gas tank for another type gas

(33) 2: Liquid raw material flow rate meter

(34) 3: Liquid raw material supply valve

(35) 4: Liquid raw material gas (titanium tetrachloride, TiCl.sub.4)

(36) 5: Source tank

(37) 5a: Internal space of source tank

(38) 6: Automatic pressure regulating device

(39) 6G.sub.1: Automatic pressure regulator for titanium tetrachloride gas

(40) 6G.sub.2: Automatic pressure regulator for ammonia gas

(41) 6G.sub.3: Automatic pressure regulator for argon gas

(42) 6G.sub.n: Automatic pressure regulator for another gas

(43) 7: Raw material gas outlet valve

(44) 7G.sub.2: Ammonia gas outlet valve

(45) 7G.sub.3: Argon gas outlet valve

(46) 7G.sub.n: Another gas outlet valve

(47) 8: Throttling unit (orifices)

(48) 8G.sub.1: Orifice for titanium tetrachloride gas

(49) 8G.sub.2: Orifice for ammonia gas

(50) 8G.sub.3: Orifice for argon gas

(51) 8G.sub.n: Orifice for another gas

(52) 9: Gas distribution passage

(53) 9G.sub.1: Titanium tetrachloride gas distribution passage

(54) 9G.sub.2: Ammonia gas distribution passage

(55) 9G.sub.3: Argon gas distribution passage

(56) 9G.sub.n: Another gas distribution passage

(57) 10: Supply gas switching valve (10G.sub.1, 10G.sub.2, 10G.sub.3, 10G.sub.n)

(58) 11: Process chamber

(59) 12: Arithmetic and control unit

(60) 12a: Temperature correction circuit

(61) 12b: Comparison circuit

(62) 12c: Input-output circuit

(63) 12d: Output circuit

(64) V.sub.0: Control valve

(65) 13: Set input terminal

(66) 14: Output signal terminal

(67) 15: Constant temperature heating device

(68) P.sub.1: Pressure of G.sub.1 (detection pressure)

(69) T.sub.1: Temperature of G.sub.1 (detection temperature)

(70) Pt: Corrected detection pressure

(71) Ps: Set pressure input signal

(72) Pd: Control signal

(73) Pot: Output signal

(74) 21: Carrier gas source

(75) 22: Pressure regulator

(76) 23: Mass flow controller

(77) 24: Liquid raw material gas (TiCl.sub.4)

(78) 25: Source tank

(79) 26: Constant temperature heating unit

(80) 27: Source tank internal pressure automatic pressure regulating device

(81) 27a:

(82) 28: Terminal

(83) 29: Process chamber

(84) 30: Heater

(85) 31: Wafer

(86) 32: Vacuum pump

(87) 33: Buffer chamber

(88) 34: Valve opening/closing mechanism

(89) 35: Vaporizer

(90) G.sub.1: Carrier gas

(91) G.sub.2: Steam of liquid raw material

(92) G.sub.0: Mixed gas

(93) G.sub.n: Another raw material gas

(94) CV Pressure control valve

(95) V.sub.1, V.sub.2, V.sub.3, V.sub.n: Opening/closing valve

(96) G.sub.0: Mixed volume