JP2011119433A - Method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of the pressure increasing, which leads to the cause of supplied surplus gas to a gas supply system when an opening and closing valve opens next time, caused by the leakage of a flow rate adjusting valve while the flow rate adjusting valve is closed because the passage system between the flow rate adjusting valve and the opening and closing valve has a certain capacity although the flow rate control of gas in semiconductor manufacturing process is performed by a mass flow controller where a valve with good closing characteristics is inserted in the output side of the flow rate adjusting valve because a small amount of gas flows out when it is closed and the flow rate adjusting valve used here is put the emphasis on adjusting flow rate. <P>SOLUTION: There is provided the method for manufacturing the semiconductor device which detects the leakage amount of gas flow when closing the flow control valve by measuring the pressure between the flow control valve on the gas discharge side of the mass flow controller and the opening and closing valve. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique effective when applied to a gas control technique in a method of manufacturing a semiconductor device.

  In Japanese Patent Laid-Open No. 11-202945 (Patent Document 1) or US Pat. No. 6,125,869 (Patent Document 2), as a self-diagnosis method of a mass flow controller, a flow control valve is in a predetermined open state. Technology that fills the front and rear piping parts including the flow control valve with a predetermined pressure gas, then opens the output control valve of the flow control valve, and detects the output pressure change at that time with the sensor provided on the output side Is disclosed.

  Japanese Patent Application Laid-Open No. 5-134762 (Patent Document 3) discloses a method for inspecting the use state of a mass flow controller from above a plurality of pressure sensors, temperature sensors, and the like provided in front and rear piping parts including a flow control valve. A technique for comparing the calculated applied voltage to the flow control valve with the actual applied voltage is disclosed.

  In Japanese Patent Application Laid-Open No. 2004-246826 (Patent Document 4), as a flow control method or an operation monitoring method of a mass flow controller, outputs of a plurality of pressure sensors provided in front and rear piping parts including a flow control valve are flow controlled. A technique for monitoring the flow rate as well as for controlling the valve is disclosed.

  In Japanese Patent Application Laid-Open No. 2004-280688 (Patent Document 5), as a flow control method or an operation monitoring method of a mass flow controller, a plurality of pipe portions provided in front and rear piping parts including a mass flow meter and a bypass passage are provided. A technique for monitoring the flow rate while using the output of the flow rate control valve and the pressure sensor to control the flow rate control valve is disclosed.

  In Japanese Patent Laid-Open No. 5-233068 (Patent Document 6), as a flow control method of a mass flow controller, outputs of pressure sensors provided at two locations on the output side of the flow control valve are used for controlling the flow control valve. Technology is disclosed.

JP-A-11-202945 US Pat. No. 6,125,869 Japanese Patent Laid-Open No. 5-134864 JP 2004-246826 A JP 2004-280688 A Japanese Patent Laid-Open No. 5-233068

  The flow rate control of gas etc. of semiconductor manufacturing equipment, etc. is controlled by referring to the bypass path provided in parallel with the thermal mass flow sensor (Thermal Mass Flow Sensor) and the output of the thermal mass flow sensor. It is performed by a mass flow controller composed of, for example. Since this flow control valve is focused on adjusting the flow rate, gas flows out even when it is closed. That is, the presence of the outflow gas when closed is inevitable. For this reason, it is common to insert an open / close valve with good closing characteristics on the output side (downstream side or gas discharge side) of the flow rate adjustment valve.

  However, since the piping system between the flow rate adjusting valve and the open / close valve has a certain capacity, the pressure in the space between the valves passes through the leak of the flow rate adjusting valve (due to the leak) while the flow rate adjusting valve is closed. ), There is a problem of increasing toward the pressure on the input side (upstream side or gas inflow side). Such a pressure increase in the space between the output side valves causes a process abnormality due to an excessive gas supply to the gas supply system when the open / close valve is opened next.

  The present invention has been made to solve these problems.

  An object of the present invention is to provide a highly reliable manufacturing method of a semiconductor device, which is intended to reduce process abnormality caused by supply of surplus gas.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  The following is a brief description of an outline of typical inventions disclosed in the present application.

  That is, one invention of the present application measures the pressure between the flow control valve on the gas discharge side of the mass flow controller and the open / close valve in the manufacturing process of the semiconductor device so that the flow rate is the same when the flow control valve is closed. The leak gas passing through the control valve is monitored.

  The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.

  That is, in the semiconductor device manufacturing process, by measuring the pressure between the flow control valve on the gas discharge side of the mass flow controller and the open / close valve, leak gas that passes through the flow control valve when the flow control valve is closed is measured. By monitoring, it is possible to prevent the occurrence of process abnormality due to excessive supply at the start of gas supply.

It is a schematic block diagram for demonstrating the structure of the flow control apparatus (mass flow controller) which comprises the principal part of the semiconductor manufacturing apparatus used for the manufacturing method of the semiconductor device of one embodiment of this application. It is a schematic block diagram which shows the whole structure of the semiconductor manufacturing apparatus used for the manufacturing method of the semiconductor device of one embodiment of this application. The essentials of a flow rate control valve (for example, an electromagnetically driven control valve such as a piezo effect actuator) of a flow rate control device (mass flow controller) that constitutes a main part of a semiconductor manufacturing device used in a method of manufacturing a semiconductor device according to an embodiment of the present application FIG. It is principal part sectional drawing of the on-off valve (for example, pneumatic drive on-off valve) of the flow control device (mass flow controller) which comprises the principal part of the semiconductor manufacturing apparatus used for the manufacturing method of the semiconductor device of one embodiment of this application. . It is a block flow figure showing a leak inspection sequence at the time of a flow control valve closing in a semiconductor manufacturing device used for a manufacturing method of a semiconductor device of one embodiment of this application. FIG. 6 is a calculation formula explanatory diagram for explaining a calculation formula in FIG. 5. It is a pressure change figure which shows the mode of the pressure change of the to-be-measured area | region in the leak test at the time of the flow control valve closing in FIG. Comparison explanation of typical characteristics of various actuators used in the flow control valve of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method according to the embodiment of the present application FIG. Gas passing through the flow rate control device when the leak at closing of the flow rate control valve of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method of one embodiment of the present application is large It is a time change figure of an actual flow rate. Gas passing through the flow rate control device when the leak at closing of the flow rate control valve of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method of one embodiment of the present application is small It is a time change figure of an actual flow rate. A gas flow immediately before a wafer processing chamber when a leak is large when a flow control valve of a flow control device (mass flow controller) constituting a main part of a semiconductor manufacturing device used in a semiconductor device manufacturing method according to an embodiment of the present application is closed. It is a time change figure of passage gas real flow rate in a way. A gas flow immediately before a wafer processing chamber when a leak is small when a flow control valve of a flow control device (mass flow controller) constituting a main part of a semiconductor manufacturing device used in a semiconductor device manufacturing method according to an embodiment of the present application is closed. It is a time change figure of passage gas real flow rate in a way. It is the apparatus block diagram which simplified and showed the structure of the gas supply system in the semiconductor manufacturing apparatus (modification: what has a vent line) used for the manufacturing method of the semiconductor device of one embodiment of this application. Device configuration showing a modification (closing of bypass line by gate valve) such as a structure of a flow control device (mass flow controller) constituting a main part in a semiconductor manufacturing device used in a method of manufacturing a semiconductor device according to an embodiment of the present application FIG. Device configuration showing a modification (closing of bypass line by spindle valve) such as a structure of a flow rate control device (mass flow controller) constituting a main part in a semiconductor manufacturing device used in a semiconductor device manufacturing method according to an embodiment of the present application FIG. Modification of the structure of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application, and its peripheral configuration (external downstream opening / closing valve) FIG. It is a schematic cross section of the tungsten thermal CVD apparatus used for the manufacturing method of the semiconductor device of one embodiment of this application. It is a gas supply system detail drawing which shows the detailed structure of the gas supply system of the tungsten thermal CVD apparatus used for the manufacturing method of the semiconductor device of one embodiment of this application. It is a process block flow figure showing details of a tungsten thermal CVD process in a manufacturing method of a semiconductor device of one embodiment of this application. It is a schematic cross-sectional view of a dry etching apparatus used for a dry etching process of an aluminum-based wiring that is a main part of a method for manufacturing a semiconductor device according to another embodiment of the present application. FIG. 10 is a device cross-sectional process flow diagram (at the time of completion of contact hole formation) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. FIG. 5 is a device cross-sectional process flow diagram (at the time of completion of formation of a lower barrier metal film in a plug portion) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in a method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application; is there. Device cross-sectional process flowchart including tungsten CVD process and aluminum-based wiring dry etching process in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application (when the formation of the upper barrier metal film of the plug portion is completed) It is. FIG. 10 is a device cross-sectional process flow diagram (at the time of completion of tungsten film embedding) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application; FIG. 10 is a device cross-sectional process flow diagram (at the time of completion of metal CMP) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. FIG. 10 is a device cross-sectional process flow diagram (at the time of completion of patterning of an aluminum-based wiring film) including a tungsten CVD process and an aluminum-based wiring dry etching process in a manufacturing method of a semiconductor device according to one embodiment or another embodiment of the present application; . FIG. 24 is a schematic device cross-sectional view illustrating a mechanism for occurrence of defects in the step illustrated in FIG. 23. In the apparatus shown in FIG. 20, it is a front sectional view of the etching apparatus for explaining the case where the adsorption of the wafer is incomplete. 20 is a gas supply timing chart (when the flow rate control valve is normal) showing the timing immediately after the start of gas supply in the tungsten nucleus forming step of FIG. FIG. 20 is a gas supply timing chart showing the timing immediately after the start of gas supply in the tungsten nucleation step of FIG. 19 (start timing delay is performed when the flow control valve is abnormal). FIG. 20 is a gas supply timing chart showing the timing immediately after the start of gas supply in the tungsten nucleation step of FIG. 19 (change the set flow rate when the flow control valve is abnormal).

[Outline of Embodiment]
First, an outline of a typical embodiment of the invention disclosed in the present application will be described.

1. A semiconductor device manufacturing method including the following steps:
(A) introducing the first semiconductor wafer into the wafer processing chamber;
(B) executing wafer processing while introducing a reactive gas into the wafer processing chamber in a state where the first semiconductor wafer is introduced via a flow rate control device;
(C) after the step (b), discharging the first semiconductor wafer from the wafer processing chamber;
(D) a step of introducing a second semiconductor wafer into the wafer processing chamber after the step (c);
(E) executing the wafer processing while introducing the reactive gas into the wafer processing chamber in a state where the second semiconductor wafer is introduced via the flow rate control device;
(F) After the step (e), a step of discharging the second semiconductor wafer from the wafer processing chamber;
Here, the flow control device includes:
(P) a gas inlet, a gas outlet, and a gas flow path connecting them;
(Q) a flow rate measurement channel provided in the gas channel between the gas inlet and the gas outlet;
(R) a flow rate sensor provided in the flow rate measurement channel;
(S) a bypass flow path provided in parallel with the flow rate measurement flow path;
(T) a flow rate control valve provided on the gas discharge port side of the flow rate measurement channel and the bypass channel,
Here, the manufacturing method of the semiconductor device further includes the following steps:
(G) A step of detecting a gas leak state when the flow control valve in the flow control device is in a closed state after the step (b) and before the step (e).

  2. In the method of manufacturing a semiconductor device according to the item 1, the wafer processing is a CVD process.

  3. In the method for manufacturing a semiconductor device according to the item 1 or 2, the wafer processing is a tungsten film CVD process.

  4). 4. In the method for manufacturing a semiconductor device according to any one of items 1 to 3, the wafer processing is a tungsten plug embedding step.

  5. In the method of manufacturing a semiconductor device according to any one of 1 to 4, the detection of the gas leak state is automatically executed.

  6). 6. In the method of manufacturing a semiconductor device according to any one of items 1 to 5, an alarm is generated when an abnormality is detected as a result of detection of the gas leak state.

  7. 7. In the method for manufacturing a semiconductor device according to any one of items 1 to 6, when an abnormality is found as a result of detecting the gas leak state, the condition of the step (e) is changed.

  8). In the method for manufacturing a semiconductor device according to any one of 1 to 7, a valve for closing the bypass flow path is provided in the flow rate control device, and the bypass flow path is closed, The gas leak state is detected by the flow rate measurement channel.

9. 9. The method for manufacturing a semiconductor device according to any one of 1 to 8, wherein the flow rate control device further includes:
(U) a pressure sensor for measuring the pressure of the gas flow path between the flow control valve and the gas outlet;
Here, the detection of the gas leak state is performed using the pressure sensor.

10. 10. The method for manufacturing a semiconductor device according to any one of 1 to 9, wherein the flow rate control device further includes:
(V) An opening / closing valve provided in the gas flow path between the pressure sensor and the gas discharge port, which opens and closes based on the opening / closing of the flow rate control valve and a signal from the manufacturing apparatus control system 27.

  11. In the method of manufacturing a semiconductor device according to the item 10, the volume of the gas flow path between the flow control valve and the opening / closing valve is 2 cc or less.

  12 In the method of manufacturing a semiconductor device according to the item 10, the volume of the gas flow path between the flow control valve and the opening / closing valve is 1 cc or less.

13. The method for manufacturing a semiconductor device according to any one of the items 10 to 12, further including the following steps:
(H) A step of detecting a gas leak state when the on-off valve is in a closed state after the step (b) and before the step (g).

  14 14. In the method for manufacturing a semiconductor device according to any one of items 1 to 13, the flow control valve is driven by a piezo actuator.

  15. 15. In the method for manufacturing a semiconductor device according to any one of 10 to 14, the open / close valve is driven by a gas pressure.

  16. 16. In the method of manufacturing a semiconductor device as described above in any one of 7 to 15, the change of the condition in the step (e) is performed on the wafer in which the gas is detected according to the leak state of the gas in which the leak is detected. The introduction timing to the room is changed.

  17. In the method of manufacturing a semiconductor device according to the item 16, the change in the introduction timing is a timing delay.

  18. 16. In the method of manufacturing a semiconductor device as described above in any one of 7 to 15, the change of the condition in the step (e) is performed on the wafer in which the gas is detected according to the leak state of the gas in which the leak is detected. The amount introduced into the room is changed.

  19. In the method of manufacturing a semiconductor device according to the item 18, the change of the introduction amount is performed by subtracting the leased gas amount from a set value of the gas introduction amount.

20. A semiconductor device manufacturing method including the following steps:
(A) introducing a semiconductor wafer into the wafer processing chamber;
(B) A step of performing wafer processing while intermittently or continuously introducing an inert gas into the wafer processing chamber in a state where the semiconductor wafer is introduced via a flow rate control device;
(C) after the step (b), discharging the semiconductor wafer from the wafer processing chamber;
Here, the flow control device includes:
(P) a gas inlet, a gas outlet, and a gas flow path connecting them;
(Q) a flow rate measurement channel provided in the gas channel between the gas inlet and the gas outlet;
(R) a flow rate sensor provided in the flow rate measurement channel;
(S) a bypass flow path provided in parallel with the flow rate measurement flow path;
(T) a flow rate control valve provided on the gas discharge port side of the flow rate measurement channel and the bypass channel,
Here, the manufacturing method of the semiconductor device further includes the following steps:
(G) A step of detecting a gas leak state when the flow control valve in the flow control device is in a closed state.

  21. In the method of manufacturing a semiconductor device according to the item 20, the wafer processing is a dry etching process.

  22. In the method for manufacturing a semiconductor device according to the item 21, the wafer processing is a dry etching process of an aluminum-based wiring film.

  23. 23. In the method for manufacturing a semiconductor device according to any one of Items 20 to 22, the inert gas is a gas containing helium as a main component for cooling the back surface of the semiconductor wafer.

  24. 24. In the method for manufacturing a semiconductor device as described above in any one of 20 to 23, the detection of the gas leak state is automatically executed.

[Description format, basic terms, usage in this application]
1. In the present application, the description of the embodiment may be divided into a plurality of sections for convenience, if necessary, but these are not independent from each other unless otherwise specified. Each part of a single example, one part is the other part of the details, or part or all of the modifications. Moreover, as a general rule, the same part is not repeated. In addition, each component in the embodiment is not indispensable unless specifically stated otherwise, unless it is theoretically limited to the number, and obviously not in context.

  Further, in the present application, the term “semiconductor device” or “semiconductor integrated circuit device” mainly refers to various types of transistors (active elements) alone, and resistors, capacitors, etc. as semiconductor chips (eg, single crystal). The one integrated on the silicon substrate). Here, as a representative of various transistors, a MISFET (Metal Insulator Semiconductor Effect Transistor) typified by a MOSFET (Metal Oxide Field Effect Transistor) can be exemplified. Note that the above-described Metal is not limited to metal, but also includes a conductive material (for example, polysilicon). At this time, as a typical integrated circuit configuration, a CMIS (Complementary Metal Insulator Semiconductor) integrated circuit represented by a CMOS (Complementary Metal Oxide Semiconductor) integrated circuit combining an N-channel MISFET and a P-channel MISFET. Can be illustrated.

  A semiconductor process of today's semiconductor integrated circuit device, that is, a LSI (Large Scale Integration) wafer process, is usually performed by carrying a silicon wafer as a raw material to a premetal process (an interlayer insulating film between the lower end of the M1 wiring layer and the gate electrode structure). Etc., contact hole formation, tungsten plug, embedding, etc.) (FEOL (Front End of Line) process) and M1 wiring layer formation, pad to final passivation film on aluminum-based pad electrode The process can be roughly divided into BEOL (Back End of Line) processes up to the formation of the opening (including the process in the package process at the wafer level). Among the FEOL processes, the gate electrode patterning process, the contact hole forming process, and the like are microfabrication processes that require particularly fine processing. On the other hand, in the BEOL process, a via and trench formation process, in particular, a relatively lower local wiring (for example, M1 to M3 in a buried wiring having a structure of about four layers, M1 in a buried wiring having a structure of about 10 layers. In particular, fine processing is required for fine embedded wiring from M to around M5. Note that “MN (usually N = 1 to 15)” represents the N-th layer wiring from the bottom. M1 is a first layer wiring, and M3 is a third layer wiring.

  2. Similarly, in the description of the embodiment and the like, the material, composition, etc. may be referred to as “X consisting of A”, etc., except when clearly stated otherwise and clearly from the context, except for A It does not exclude what makes an element one of the main components. For example, as for the component, it means “X containing A as a main component”. For example, “silicon member” is not limited to pure silicon, but also includes SiGe alloys, other multi-component alloys containing silicon as a main component, and members containing other additives. Needless to say.

  3. Similarly, suitable examples of graphics, positions, attributes, and the like are given, but it is needless to say that the present invention is not strictly limited to those cases unless explicitly stated otherwise, and unless otherwise apparent from the context.

  4). In addition, when a specific number or quantity is mentioned, a numerical value exceeding that specific number will be used unless specifically stated otherwise, unless theoretically limited to that number, or unless otherwise clearly indicated by the context. There may be a numerical value less than the specific numerical value.

  5. “Wafer” usually refers to a single crystal silicon wafer on which a semiconductor integrated circuit device (same as a semiconductor device and an electronic device) is formed, but an insulating substrate such as an epitaxial wafer, an SOI substrate, an LCD glass substrate and the like. Needless to say, a composite wafer such as a semiconductor layer is also included.

  6). In the present application, “semiconductor manufacturing apparatus” means a normal semiconductor unit, a semiconductor integrated circuit device, and a CVD (Chemical Vapor Deposition) apparatus, an etching apparatus, a sputtering film forming apparatus, and other surfaces used for manufacturing a liquid crystal display device. Including processing equipment.

  7. In the present application, the pressure is displayed based on the atmospheric pressure 101300 Pascal.

[Details of the embodiment]
The embodiment will be further described in detail. In the drawings, the same or similar parts are denoted by the same or similar symbols or reference numerals, and description thereof will not be repeated in principle.

  In the accompanying drawings, hatching or the like may be omitted even in a cross section when it becomes complicated or when the distinction from the gap is clear. In relation to this, when it is clear from the description etc., the contour line of the background may be omitted even if the hole is planarly closed. Furthermore, even if it is not a cross section, it may be hatched to clearly indicate that it is not a void.

1. Description of the structure and operation of a flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the method of manufacturing a semiconductor device according to an embodiment of the present application, and the overall configuration of the semiconductor manufacturing apparatus (mainly 1 and 2)
FIG. 1 is a schematic configuration diagram for explaining the structure of a flow rate control device (mass flow controller) that constitutes a main part of a semiconductor manufacturing apparatus used in a semiconductor device manufacturing method according to an embodiment of the present application. FIG. 2 is a schematic configuration diagram showing an overall configuration of a semiconductor manufacturing apparatus used in the method for manufacturing a semiconductor device according to an embodiment of the present application. Based on these, the structure and operation of the flow control device constituting the main part of the semiconductor manufacturing apparatus used in the method of manufacturing a semiconductor device according to one embodiment of the present application, the overall configuration of the semiconductor manufacturing apparatus, and the like will be described. Here, an example in which a downstream air pressure on-off valve, a pressure sensor, and the like are incorporated in the mass flow controller is shown, but these may be externally attached.

  As shown in FIG. 1, a flow rate control device 1 (mass flow controller) includes a bypass channel 5 having a large conductance and a flow rate measuring channel 4 having a small conductance connected in parallel thereto as a main part. 2 and a process gas flow path between the process gas outlet 3. The flow rate measurement channel 4 is provided with a flow rate sensor 6 (thermal mass flow sensor) including resistance heating bodies 9 and 10, and a bridge type detection circuit 15 that forms a bridge together with the resistance heating bodies 9 and 10, The flow rate is detected. The detected flow rate data is amplified and corrected by the amplification correction circuit 16 and then output to the manufacturing apparatus control system 27 (FIG. 2) or the like via the detection data output terminal 18. The detected flow rate data is sent to the comparison control circuit 17 and compared with the flow rate setting data sent from the manufacturing apparatus control system 27 via the input terminal 19 such as a set value. The state of the flow rate control valve 7 provided in the discharge channel 11 is controlled. Note that the flow rate control circuit 8 is configured by the bridge type detection circuit 15, the amplification correction circuit 16, the comparison control circuit 17, and the like. Since the flow rate control valve 7 is for stably controlling the flow rate, the shut-off characteristic is not good like a general pneumatic on-off valve, and there is some leakage even in a closed state. For this reason, an open / close valve 12 (pneumatic open / close valve) is provided on the gas discharge passage 11 between the flow control valve 7 and the process gas discharge port 3. The on-off valve 12 is pneumatically controlled by the manufacturing apparatus control system 27 via the pneumatic input terminal 21. A pressure sensor 14 is provided in the gas discharge passage 11 between the flow control valve 7 and the opening / closing valve 12 in order to measure the pressure in that portion. The output of the pressure sensor 14 can be directly supplied to the manufacturing apparatus control system 27 via the external output terminal 22 that outputs the detected pressure. Further, the pressure sensor 14 can exchange data with the manufacturing apparatus control system 27 and the like via the flow rate control circuit 8. That is, the pressure sensor 14 can output data and signals to the flow rate control circuit 8, the manufacturing apparatus control system 27, etc., or the pressure sensor 14 can be controlled by the flow rate control circuit 8, the manufacturing apparatus control system 27, etc. It has become.

Next, the overall configuration of the semiconductor manufacturing apparatus 23 used in the method of manufacturing a semiconductor device according to the embodiment of the present application will be described with reference to FIG. As shown in FIG. 2, the process gas supplied from the process gas constant pressure source 24 (for example, about 100,000 Pascals, taking WF ₆ as an example, and the gas is WF ₆ unless otherwise specified) is a gas inflow channel. 25 is supplied to the flow control device 1 described in FIG. Thereafter, the process gas that has passed through the flow control device 1 is supplied to the wafer processing chamber 26 (process chamber) for processing the semiconductor wafer 28 via the gas discharge channel 11. Here, the wafer processing chamber 26, the flow rate control device 1, and the like are controlled directly or indirectly by the manufacturing apparatus control system 27. The manufacturing apparatus control system 27 may be built in the semiconductor manufacturing apparatus 23, but may be provided outside the semiconductor manufacturing apparatus 23, or the control system and the semiconductor built in the semiconductor manufacturing apparatus 23. A control system including both of the control systems provided outside the manufacturing apparatus 23 may be used.

2. Detailed description of flow control valves and open / close valves used in a flow control device (mass flow controller) or the like constituting a main part of a semiconductor manufacturing apparatus used in a semiconductor device manufacturing method according to an embodiment of the present application (mainly FIG. 3). And FIG. 4 and FIG. 8)
In this section, an outline of the structure of the flow control valve and the on-off valve described in Section 1 will be described.

  FIG. 3 is a flow rate control valve (for example, an electromagnetically driven control valve using a piezo effect actuator or the like) of a flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method of one embodiment of the present application. FIG. FIG. 4 is a cross-sectional structure of a main part of an on-off valve (for example, a pneumatically driven on-off valve) of a flow rate control device (mass flow controller) constituting a main part of a semiconductor manufacturing apparatus used in a method for manufacturing a semiconductor device according to an embodiment of the present application. FIG. FIG. 8 shows typical characteristics of various actuators used in the flow rate control valve of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method according to the embodiment of the present application. FIG. Based on these, the detailed structures of the flow control valve and the open / close valve used in the flow control device (mass flow controller) or the like constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application. Etc. will be explained.

  First, an example of the flow control valve 7 built in the flow control device 1 described in FIG. 1 will be described. As shown in FIG. 3, the piezoelectric effect actuator driven flow control valve 7 includes a relatively hard flow control surface 43 (usually annular) between the gas inflow portion 31 and the gas discharge portion 32, and the flow control valve 43. An output side cavity 44 (usually an annular shape) is provided so as to surround it. A metal diaphragm 33 is arranged so as to oppose these, and the piezoelectric effect actuator 34 slightly deforms the metal diaphragm 33 to control a minute gap between the lower surface of the metal diaphragm 33 and the flow control surface 43. Thus, the gas flow rate is controlled.

  As shown in FIG. 8, the type of the actuator 34 of the flow rate control valve 7 includes a piezo method, a solenoid method, a thermal method, and the like. The piezo method described here is the speed, driving force, etc. Needless to say, a solenoid system, a thermal system, and the like can also be applied.

  On the other hand, as shown in FIG. 4, the on-off valve 12 is provided with a seal ring installation portion 40 in the process gas flow path between the process gas inflow portion 41 and the process gas discharge port 3, and a seal resin ring 38 is provided there. The metal diaphragm 37 is provided between the cylinder 35 and the cylinder 35 so as to face the cylinder. Then, the piston 39 is driven by compressed air (air pressure) supplied from the air pressure input terminal 21 to the air pressure chamber 36, thereby pressing the metal diaphragm 37 against the seal resin ring 38 to achieve complete closure.

  As explained here, since the flow control valve 7 cannot theoretically be completely closed, an open / close valve 12 is inserted downstream of the flow control valve 7 as shown in FIG. To open and close.

3. Description of leak check sequence when flow control valve is closed in semiconductor manufacturing apparatus used in semiconductor device manufacturing method of one embodiment of the present application (mainly FIGS. 5 to 7)
In this section, the leak check sequence when the flow control valve is closed (sequence for automatically executing the leak check when the flow control valve is closed) will be specifically described based on the descriptions in sections 1 and 2. Here, a mass flow controller having a full-scale flow rate of about 30 SCCM will be described as an example.

  FIG. 5 is a block flow diagram showing a leak test sequence when the flow control valve is closed in the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application. FIG. 6 is an explanatory diagram of calculation formulas for explaining the calculation formulas in FIG. FIG. 7 is a pressure change diagram showing a state of pressure change in the measurement region in the leak test when the flow control valve is closed in FIG. Based on these, a leak check sequence when the flow control valve is closed in the semiconductor manufacturing apparatus used in the method of manufacturing a semiconductor device according to the embodiment of the present application will be described.

  As shown in FIG. 7 (and FIG. 1), when the flow control valve 7 and the open / close valve 12 are in the open state, the pressure of the gas discharge passage 11 between the flow control valve 7 and the open / close valve 12 is relatively low. It remains at a low value P1 (for example, about −101300 Pascal). At this time, a leak check is started when the flow control valve is closed (leak confirmation process at start 50 in FIG. 5). At the start of the leak confirmation process at the time of closing, the pressure P1 in the gas discharge passage 11 between the flow control valve 7 and the opening / closing valve 12 is measured using the pressure sensor 14 (reference pressure measurement 51a in FIG. 5). At substantially the same time, the flow control valve 7 and the opening / closing valve 12 are closed. The value of the pressure P1 corresponds to the pressure in the wafer processing chamber 26 shown in FIG. 2, and if it is a vacuum processing apparatus, it is a value that is very low compared to vacuum, that is, atmospheric pressure. If so, it is about atmospheric pressure.

Thereafter, the pressure of the gas discharge passage 11 between the flow control valve 7 and the opening / closing valve 12 gradually increases. After X minutes (for example, 0.2 minutes), the pressure sensor 14 is used again to measure the pressure P2 (for example, about 100,000 Pascals) in the gas discharge passage 11 between the flow control valve 7 and the opening / closing valve 12. (Measurement of ultimate pressure 51b in FIG. 5). Next, the calculation formula shown in FIG. 6 is referred to, and the closing leak amount is calculated (calculation formula reference step 52 in FIG. 5). That is, when the capacity Y of the dead space between the flow control valve 7 and the opening / closing valve 12 is about 0.6 cc,
The closing leak amount (actually measured closing leak amount) is about 0.1 SCCM. The algorithm so far is stored in the flow rate control circuit 8 or the manufacturing apparatus control system 27.

  Next, as shown in FIG. 5, the calculated actual leak amount at closing is compared with the set leak amount at closing (for example, 0.15 SCCM) set as a threshold, and the actual leak amount is compared with the set leak amount. If it is smaller, there is no problem and, for example, production is continued (production continuation determination 54). On the contrary, if the actually measured leak amount is equal to or larger than the set leak amount, an alarm is issued (alarm generation step 55). Here, when necessary, the flow control valve 7 is replaced (flow control valve replacement step 56).

  When an abnormality is detected, the gas supply amount at the time of subsequent wafer processing may be automatically adjusted. For example, the supply amount of tungsten hexafluoride gas in section 10 or cooling gas in section 11 may be automatically changed.

4). Consideration of semiconductor manufacturing apparatus or flow rate control apparatus used in semiconductor device manufacturing method of one embodiment of the present application (mainly FIGS. 9 to 12)
In this section, the merits of the embodiments described in sections 1 to 3 and problems when not using them will be considered.

  FIG. 9 shows the inside of the flow rate control device when a leak is large when the flow rate control valve of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the method of manufacturing a semiconductor device according to the embodiment of the present application is closed. It is a time change figure of actual passage gas actual flow. FIG. 10 shows the inside of the flow rate control device when the leak is small when the flow rate control valve of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method of one embodiment of the present application is closed. It is a time change figure of actual passage gas actual flow. FIG. 11 shows a state immediately before the wafer processing chamber when a leak is large when the flow control valve of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method according to the embodiment of the present application is closed. It is a time change figure of the passage gas real flow rate in this gas channel. FIG. 12 shows the state immediately before the wafer processing chamber when the leakage at the closing of the flow control valve of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application is small. It is a time change figure of the passage gas real flow rate in this gas channel. Hereinafter, with reference to FIGS. 1A and 1B, based on these drawings, the advantages of the above-described embodiment, problems when not using the embodiment, and the like will be described.

  First, the time change of the actual flow rate at the point A (FIGS. 2 and 3) when the leak at closing is large will be described with reference to FIG. As shown in FIG. 9, when the flow control valve 7 and the opening / closing valve 12 are opened, the flow rate rises toward the set flow rate and converges rapidly in a relatively short time. Next, the time change of the actual flow rate at the point A (FIGS. 2 and 3) when the leak at closing is small will be described with reference to FIG. As shown in FIG. 10, also at this time, when the flow control valve 7 and the opening / closing valve 12 are opened, the flow rate rises toward the set flow rate and converges rapidly in a relatively short time. That is, it is understood that the time change of the actual flow rate at the point A (FIGS. 2 and 3) does not substantially depend on the leakage amount at the time of closing. This is because surplus gas due to leakage at the time of closing is downstream of point A.

  Next, the time change of the actual flow rate at the point B (FIGS. 2 and 3) is observed. First, the time change of the actual flow rate at point B (FIG. 1) when the leak at closing is large will be described with reference to FIG. As shown in FIG. 11, when the flow control valve 7 and the opening / closing valve 12 are opened, the flow rate rises toward the set flow rate in a relatively short time, but overshoots beyond the set flow rate and then takes time. It converges to the flow rate. In such a case, the shaded portion corresponds to the excessive supply of gas. On the other hand, when the leak at the time of closing is small, the time change of the actual flow rate at the point B (FIG. 1) will be described with reference to FIG. As shown in FIG. 12, when the flow control valve 7 and the opening / closing valve 12 are opened, the flow rate rises toward the set flow rate and converges rapidly in a relatively short time. That is, when the leak at the time of closing is small, the same behavior as the point A is shown. This is because when the leak at closing is small, excess gas is not accumulated in the dead space between the flow control valve 7 and the opening / closing valve 12.

  As described above, the dead space between the flow control valve 7 and the on-off valve 12 can be obtained by using the semiconductor manufacturing apparatus 23 or the flow control apparatus 1 that can check the leakage at the time of closing with a simple procedure. Various problems due to surplus gas accumulated in the gas can be avoided. Note that mass flow controllers (flow rate control devices) in which these problems are particularly important mainly have a full-scale flow rate of 1 SCCM (Standard Cubic Centimeter per Minute, that is, 1 cc / min under the conditions of 0 degrees Celsius and 1 atmosphere) to about 1000 SCCM. Of the range.

  Note that the smaller the dead space capacity between the flow control valve 7 and the on-off valve 12, the smaller the problem due to the accumulation of surplus gas. Therefore, the dead space capacity should be as small as possible. In the above-described embodiment, for example, it is about 0.6 cc, but 2 cc or less is desirable in a practical range. Moreover, 1 cc or less is particularly suitable for mass production.

  In order to keep the dead space capacity small, it is particularly effective to incorporate one or both of the on-off valve 12 and the pressure sensor 14 into the flow control device 1.

  In the above embodiment, since there is no substantial orifice between the flow control valve 7 and the on-off valve 12, a degree of freedom as a flow control unit of the flow control device or the semiconductor manufacturing apparatus can be ensured. .

5). Description of Modifications (Containing Vent Lines) etc. Regarding Main Structure of Semiconductor Manufacturing Device Used in Semiconductor Device Manufacturing Method of One Embodiment of the Present Application (Mainly FIG. 13)
In this section, a modification of the overall configuration of the semiconductor manufacturing apparatus used in the method for manufacturing the semiconductor device according to the embodiment shown in FIG.

  FIG. 13 is an apparatus configuration diagram showing a simplified configuration of a gas supply system in a semiconductor manufacturing apparatus (modified example: having a vent line) used in the method of manufacturing a semiconductor device according to an embodiment of the present application.

  As shown in FIG. 13, a three-way switching opening / closing valve 13 is provided in the gas discharge channel 11 immediately before the wafer processing chamber 26, and before the gas is started to be supplied to the wafer processing chamber 26, the gas is supplied to the vent line 20. By detouring, the gas flow is stabilized, and at a stable stage, the three-way switching on-off valve 13 is switched to start supplying gas to the wafer processing chamber 26. In this case as well, as described in Sections 1 to 4, applying the leak check when the flow control valve is closed can avoid adverse effects on the process due to excessive supply at the initial stage of gas supply. In this case, since the gas stability or the time can be shortened, the time for discarding the gas by the vent line 20 can be shortened, which is effective in saving valuable gas.

  Since other points are the same as those described with reference to FIG. 2, the description will not be repeated.

6). Description of modification (closing of bypass line by gate valve) such as the structure of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method according to the embodiment of the present application (mainly Fig. 14)
In this section, an additional pressure sensor or the like is provided in a flow control device (mass flow controller) which is a main part of the semiconductor manufacturing apparatus used in the manufacturing method of the semiconductor device according to the embodiment shown in FIG. A modified example capable of performing a leak check when closing a flow control valve that is not used will be described.

  FIG. 14 shows a modification of the structure of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application (closing of the bypass line by the gate valve). FIG.

  As shown in FIG. 14, the difference from the mass flow controller 1 of FIG. 1 is that a gate valve 29 is provided in the same part so that the bypass flow path 5 can be closed, and the flow control valve 7 and the downstream side. This is a point where the pressure sensor 14 is not provided in the flow path between the opening and closing valves 12 (there may be a pressure sensor). In this case, the leak check when the flow rate control valve 7 is closed is slightly different from the case of FIG. That is, if the bypass flow path 5 is closed by closing the gate valve 29 with the flow control valve 7 and the downstream opening / closing valve 12 closed, all the gas flowing through the gas flow path in the mass flow controller 1 is flow measurement flow. The road 4 will be passed. Then, the flow rate of the flow rate measurement flow path 4 at this time becomes a leak flow rate when the flow rate control valve is closed. When the closed leak flow rate is equal to or higher than a certain reference value, an alarm is sent in the same manner as in FIG. 5, and a necessary process start or process stop signal is sent.

  This example is effective when the accuracy of the pressure sensor (vacuum gauge) 14 is not achieved due to the pressure range (when it is difficult to use).

7). Description of modification (closing of bypass line by spindle valve) such as the structure of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing device used in the semiconductor device manufacturing method of one embodiment of the present application (mainly Fig. 15)
In this section, an additional pressure sensor or the like is provided in a flow control device (mass flow controller) which is a main part of the semiconductor manufacturing apparatus used in the manufacturing method of the semiconductor device according to the embodiment shown in FIG. Another modified example capable of performing a leak check when closing a flow control valve that is not used will be described.

  FIG. 15 shows a modified example (closing of the bypass line by the spindle valve) of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application. FIG.

  Although it is exactly the same as the section 6, as shown in FIG. 15, the gate valve 29 in FIG. The remaining points are the same as in section 6. In this case, the bypass flow path 5 is closed by moving the spindle valve 30 to the right side. This example is particularly effective when the mass flow controller 1 having the spindle valve type bypass passage 5 is used.

8). Modification of the structure of the flow rate control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application, and its peripheral configuration (external downstream opening / closing valve) Explanation (mainly FIG. 16)
In this section, the downstream on-off valve 12 (empty) in the flow control device (mass flow controller), which is the main part of the semiconductor manufacturing device used in the manufacturing method of the semiconductor device according to the embodiment shown in FIG. A modification of the overall configuration of the gas supply system of the semiconductor manufacturing apparatus shown in FIGS.

  In addition, a description will be given of performing a leak check when the downstream on-off valve 12 (the same applies to FIG. 16 and other drawings) before the flow control valve is closed.

  FIG. 16 shows a modification of the structure of the flow control device (mass flow controller) constituting the main part of the semiconductor manufacturing apparatus used in the semiconductor device manufacturing method according to the embodiment of the present application and its peripheral configuration (external downstream side) It is an apparatus block diagram which shows an on-off valve.

  As shown in FIG. 16, the feature here is that, unlike the case of FIG. 1, the downstream opening / closing valve 12 is externally attached to the mass flow controller 1. Other points are the same as those described with reference to FIGS. 1 and 2 and the like, and description thereof will not be repeated.

  Next, using this example, in order to eliminate the possibility that the flow control valve 7 and the downstream on-off valve 12 leak at the same time, so that the leak check when the flow control valve 7 is closed cannot be performed correctly, the on-off valve 12 A leak check (hereinafter referred to as a prior leak check when the downstream side open / close valve is closed) will be described. This prior leak check at the time of closing the downstream side opening / closing valve is not limited to this example, but using the existing upstream side opening / closing valve 42 or the newly installed upstream side opening / closing valve 42, FIG. , 2, 13-15, 18, and 20 can be similarly applied.

  The leak check at the time of closing the upstream downstream opening / closing valve is preferably performed immediately before the leak check at the time of closing the flow control valve in the following procedure. However, it is also possible to carry out with an interval that does not change the state of the valve. This has the advantage that the idle time of the device can be used.

  First, with the upstream side open / close valve 42 and the flow rate control valve 7 open, the downstream side open / close valve 12 to be inspected is closed, and the upstream side of the open / close valve 12 is filled with gas. Next, the on-off valve 42 is closed and the change in the pressure sensor 14 (pressure gauge) is observed. If the change in pressure is equal to or greater than a certain reference value, it is determined that there is an abnormality, and an alarm is sent as in FIG. Then, a necessary process start or process stop signal is transmitted. If necessary, the downstream opening / closing valve 12 is replaced (or a signal indicating that replacement is necessary is issued). On the other hand, if the change in pressure does not reach a certain reference value, the leak check is performed when the flow rate control valve 7 is closed as normal, as in FIG.

9. Description of device cross-sectional process flow including tungsten CVD process and aluminum-based wiring dry etching process of the semiconductor device manufacturing method of one embodiment or other embodiments of the present application (mainly FIGS. 21 to 26)
In this section, a series of flow of the semiconductor manufacturing process including the element processes described in sections 10 and 11 (peripheral of the previous element process is illustrated) will be briefly described by a device cross-sectional flow.

  FIG. 21 is a device cross-sectional process flow diagram (at the time of completion of contact hole formation) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. is there. 22 is a device cross-sectional process flow diagram (formation of a lower barrier metal film of a plug portion) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. At the time of completion). FIG. 23 is a device cross-sectional process flow diagram (formation of an upper barrier metal film of a plug portion) including a tungsten CVD process and a dry etching process of an aluminum-based wiring in a method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. At the time of completion). FIG. 24 is a device cross-sectional process flow diagram (at the time of completing the tungsten film embedding) including a tungsten CVD process and a dry etching process of aluminum wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. . FIG. 25 is a device cross-sectional process flow diagram (at the time of completion of metal CMP) including a tungsten CVD process and a dry etching process of aluminum wiring in the method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application. FIG. 26 is a device cross-sectional process flow diagram (at the time of completion of patterning of the aluminum-based wiring film) including the tungsten CVD process and the aluminum-based wiring dry etching process of the semiconductor device manufacturing method according to one embodiment or other embodiments of the present application. is there. Based on these drawings, a device cross-sectional process flow including a tungsten CVD process and a dry etching process of aluminum wiring in a method of manufacturing a semiconductor device according to one embodiment or another embodiment of the present application will be described.

  As shown in FIG. 21, for example, an STI buried insulating film 71 (field insulating film) and an N-type high-concentration source that becomes a part of the N-channel MISFET 80 are formed in the surface 28a of the P-type single crystal silicon substrate 28. A drain region 72, an N-type source / drain extension region 73, and the like are formed. Further, a gate insulating film 74 that becomes a part of the N-channel MISFET 80, a gate electrode 75 such as polysilicon, a cap insulating film 76, a sidewall spacer insulating film 77, and the like are formed on the surface 28a of the semiconductor wafer 28. A premetal insulating film 78 is formed on these, and a contact hole 79 is opened.

  Next, as shown in FIG. 22, a lower barrier metal film 81 (for example, a titanium film having a thickness of about several nm to 10 nm, for example) is formed on almost the entire surface 28a of the semiconductor wafer 28 by sputtering film formation, for example. ).

  Next, as shown in FIG. 23, the upper layer of the plug portion is formed on almost the entire surface 28a of the semiconductor wafer 28 by, for example, sputtering film formation (may be formed by nitridation or the like on the upper portion of the titanium film). Barrier metal film 82 (for example, a titanium nitride film having a thickness of several nm to 10 nm) is formed.

  Next, as shown in FIG. 24, a contact hole 79 is buried in a tungsten film 83 having a thickness of about 200 nm, for example, by the method shown in section 10 over almost the entire surface 28a of the semiconductor wafer 28, and a premetal is formed. The upper surface of the insulating film 78 is covered.

  Next, as shown in FIG. 25, the lower barrier metal film 81, the upper barrier metal film 82 and the tungsten film 83 outside the contact hole 79 and on the upper surface of the premetal insulating film 78 are removed by metal CMP (Chemical Mechanical Polishing) or the like. , Planarize the upper surface.

  Next, as shown in FIG. 26, a lower-layer barrier metal film 91 (for example, a titanium film having a thickness of about 10 nm) is formed on almost the entire surface 28a of the semiconductor wafer 28 by, for example, sputtering film formation. . Subsequently, an upper barrier metal film 92 (for example, a titanium nitride film having a thickness of about 30 nm) is formed on almost the entire surface 28a of the semiconductor wafer 28 by sputtering film formation, for example. Further, the aluminum-based wiring film main portion 93 of the first layer having a thickness of, for example, about 300 nm is added to almost the entire surface 28a of the semiconductor wafer 28 by sputtering, for example. An aluminum alloy film). Next, a cap metal film 94 (titanium film) having a thickness of, for example, about 10 nm is formed on almost the entire surface 28a of the semiconductor wafer 28 by, for example, sputtering film formation. Finally, an antireflection film 95 (titanium nitride film) is formed on almost the entire surface 28a of the semiconductor wafer 28 by sputtering film formation, for example.

  Next, this multilayer film, that is, the aluminum-based wiring film 96 is patterned by dry etching or the like, so that the shape shown in FIG. 26 is obtained. Thereafter, the normal wiring process is repeated, and therefore, they are not repeated.

  The details of the CVD process of the tungsten film described here and a technique for avoiding a process trouble occurring at that time will be described in Section 10.

  Further, section 11 describes a technique for avoiding the process trouble that occurs during the dry etching of the aluminum-based wiring film 96 described here.

10. Description of the tungsten CVD process, which is the main part of the method of manufacturing a semiconductor device according to an embodiment of the present application (mainly FIGS. 17 to 19 and FIGS. 29 to 31)
In this section, an example will be described in which the leak check process for closing the flow control valve described in section 3 is incorporated into a specific semiconductor manufacturing element process. Here, the tungsten thermal CVD process will be specifically described.

  FIG. 17 is a schematic cross-sectional view of a tungsten thermal CVD apparatus used in the method for manufacturing a semiconductor device according to one embodiment of the present application. FIG. 18 is a gas supply system detail view showing the detailed structure of the gas supply system of the tungsten thermal CVD apparatus used in the method of manufacturing a semiconductor device according to one embodiment of the present application. FIG. 19 is a process block flow diagram showing details of the tungsten thermal CVD process in the method of manufacturing a semiconductor device according to one embodiment of the present application. FIG. 29 is a gas supply timing chart (when the flow rate control valve is normal) showing the timing immediately after the start of gas supply in the tungsten nucleus forming step of FIG. FIG. 30 is a gas supply timing chart showing the timing immediately after the start of gas supply in the tungsten nucleus forming step of FIG. 19 (start timing delay is performed when the flow control valve is abnormal). FIG. 31 is a gas supply timing chart showing the timing immediately after the start of gas supply in the tungsten nucleation step of FIG. 19 (the set flow rate is changed when the flow control valve is abnormal). Based on these, the tungsten CVD process, which is the main part of the method of manufacturing a semiconductor device according to the embodiment of the present application, will be described.

  First, the thermal CVD apparatus 45 to be used will be briefly described. As shown in FIG. 17, a wafer holder 47 is provided in the wafer processing chamber 26, and a heater 48 is embedded in the vicinity of the upper surface thereof. On the wafer holder 47, the semiconductor wafer 28 is placed with its front main surface 28a (the surface opposite to the back surface 28b) facing up. A shower head 46 is provided above the semiconductor wafer 28, and a reactive gas, a process gas, a carrier gas, a purge gas, a cleaning gas, and the like are provided through the gas introduction path 11 of the wafer processing chamber as necessary. An additive gas or the like is supplied. A vacuum exhaust system 57 (exhaust pipe) is connected below the wafer processing chamber 26 and is evacuated as necessary, for example, by a dry pump 58 or the like.

  FIG. 18 shows a detailed configuration of an example upstream of the gas discharge passage 11 (gas introduction passage of the wafer processing chamber) in FIG. The most upstream end of each gas flow path is connected to an argon gas source, a tungsten hexafluoride source, a monosilane gas source, a hydrogen gas source, a nitrogen gas source, etc., and each upstream open / close valve (pneumatic open / close valve) 42a. , 42b, 42c, 42d, 42e and the flow rate control devices (mass flow controllers) 1a, 1b, 1c, 1d, 1e are basically joined to the gas discharge passage 11 (through a plurality of gas introduction pipes 11). Although it may reach the wafer processing chamber 26, it is not essential here and will be described in a simplified manner).

  Next, the detailed steps of the tungsten thermal CVD process will be described. As shown in FIG. 19 (see also FIGS. 17 and 18), first, a semiconductor wafer 28 (first semiconductor wafer) is introduced into the wafer processing chamber 26 (wafer introduction step 101).

  Next, introduction of an inert gas or the like (for example, each gas has a flow rate of about 300 SCCM of argon gas or about 300 SCCM of nitrogen gas) is started (gas introduction start step 102). The time required for this step is, for example, about 6 seconds.

  Next, the wafer 28 is heated to, for example, about 390 degrees Celsius (wafer heating step 103). The flow rate of each supply gas at this time is, for example, about monosilane gas about 30 SCCM, argon gas about 2000 SCCM, and nitrogen gas about 300 SCCM. The time required for this step is, for example, about 15 seconds.

  After that, it is preferable from the viewpoint of process stability and the like to shift to the tungsten nucleation process 104 as shown by a dashed line in FIG. That is, when the function of each gas flow control valve in the tungsten nucleation process 104 is normal, the process proceeds to the tungsten nucleation process 104 according to the normal sequence, and the supply of each process gas is performed at the timing shown in FIG. Start.

  However, if it is known that the WF6 mass flow controller 1b has a leakage at the time of closing, the process of changing the WF6 introduction timing 103 ′ is executed before the wafer heating step 103 (or promptly thereafter), and the WF6 mass flow is performed. By taking measures such as delaying the WF6 gas introduction timing by 0.5 seconds, for example, according to the leak amount at the time of closing of the controller 1b (FIG. 30), production can be continued even if the WF6 mass flow controller 1b remains in the leak state at the time of closing. Is possible. As another means for avoiding leakage at closing, when the amount of WF6 leaked at closing is known in the WF6 introduction amount change 103 ′, a method of feeding back that amount to the set value of the WF6 mass flow controller 1b is also effective. (FIG. 31). By such processing such as timing change and introduction amount change, it is possible to extend the replacement life of the valve. In addition, as a simple countermeasure when the leak at the time of closing is not so large, after the leak check, there is a problem between the flow control valve 7 (FIG. 1) and the open / close valve 12 of the flow control device in question (the flow control device 1b in this example). The channel may be evacuated (evacuation time is, for example, about 5 seconds) using an exhaust system on the wafer processing chamber 26 side.

  Next, a tungsten nucleation process 104 (the degree of vacuum is, for example, about 3000 Pascal and the wafer temperature remains at about 390 degrees Celsius) is performed to form a tungsten film of, for example, about 10 nm. The flow rate of each supply gas at this time is, for example, about tungsten hexafluoride gas 40 SCCM, monosilane gas 10 SCCM, hydrogen gas 1000 SCCM, argon gas 1000 SCCM, nitrogen gas 300 SCCM. The time required for this step is, for example, about 10 seconds.

  Next, the intermediate gas purge 105 is executed. The flow rate of each supply gas at this time is, for example, about hydrogen gas 2000 SCCM, argon gas 3000 SCCM, and nitrogen gas 300 SCCM. The time required for this step is, for example, about 3 seconds.

  Next, an embedded tungsten film forming step 106 (the degree of vacuum is, for example, about 10,000 Pascal and the wafer temperature remains at about 390 degrees Celsius) is performed to form a tungsten film of, for example, about 200 nm. The tungsten hexafluoride gas is about 80 SCCM, the hydrogen gas is about 500 SCCM, and the argon gas is about 1000 SCCM. The time required for this step is, for example, about 70 seconds.

  Next, the final gas purge 107 is executed. The flow rate of each supply gas at this time is, for example, about hydrogen gas 500 SCCM, argon gas 1000 SCCM, and nitrogen gas 300 SCCM. The time required for this step is, for example, about 10 seconds.

  Next, the semiconductor wafer 28 (first semiconductor wafer) is discharged from the wafer processing chamber 26 (wafer discharge step 108). Subsequently, the next semiconductor wafer 28 (second semiconductor wafer) is introduced into the wafer processing chamber 26. Thereafter, the wafer introduction step 101 to the wafer discharge step 108 (unit wafer processing cycle) are repeated as before. Usually, this unit wafer processing cycle is continued until all the wafers belonging to the batch are processed.

  At this time, as shown in FIG. 19, for the tungsten hexafluoride gas system, after the buried tungsten film forming step 106 is completed, the tungsten hexafluoride gas system (tungsten hexafluoride gas source, upstream side open / close valve 42b, mass flow controller 1b). The leak check step 109 when the flow rate control valve is closed is executed for the gas introduction path 11 of the wafer processing chamber, the system including the wafer processing chamber 26 and the like. The procedure of the leak check step 109 when the flow control valve is closed is the same as that described with reference to FIG. At this time, the opening / closing valve 42b on the upstream side in FIG. 18 is in an open state throughout. As described above, such a check is performed when an excess gas (for example, for example, flows in the flow path between the flow control valve 7 and the downstream on-off valve 12 when the flow control valve 7 leaks when closed. This is because, in the initial stage of the nucleation step 104, the fluorine component of the tungsten hexafluoride gas introduced excessively causes a device defect by etching the underlying barrier metal. .

  The leak check step 109 when the flow rate control valve is closed may be executed during the tungsten film forming process for the preceding wafer (first wafer) and the next wafer (second wafer) in the batch. The processing may be performed between all wafer processing, but may be performed every few wafers or once to several times within a batch. Further, even between batches, the process may be executed between the tungsten film forming processes for the last wafer (first wafer) of the preceding batch and the first wafer (second wafer) of the next batch.

  It goes without saying that the same leak check is applied to silane gas (SiH 4) and other mass flow controllers as necessary.

11. Description of the dry etching process for aluminum-based wiring, which is the main part of the method for manufacturing a semiconductor device according to another embodiment of the present application (mainly FIG. 20)
In this section, as in section 9, an example in which the leak check process for closing the flow control valve described in section 3 is incorporated into a specific semiconductor manufacturing element process will be described. In this example, a dry etching process for aluminum wiring will be specifically described.

  FIG. 20 is a schematic cross-sectional view of a dry etching apparatus used in a dry etching process for aluminum-based wiring, which is a main part of a method for manufacturing a semiconductor device according to another embodiment of the present application.

  First, the structure of an etching apparatus 59 used in a dry etching process for aluminum-based wiring, which is a main part of a method for manufacturing a semiconductor device according to another embodiment of the present application, will be described. As shown in FIG. 20, a wafer holder 47 is provided in the wafer processing chamber 26, and a semiconductor wafer 28 to be processed is placed on the upper surface thereof with its front side 28a facing up. A wafer back surface cooling gas system 60 (cooling gas flow path) is provided in the wafer holder 47 and on the back surface side thereof, and an inert gas (cooling gas) such as helium gas is controlled in flow rate from the gas constant pressure source 24. It is supplied via the device 7. Thereby, in the dry etching, the temperature of the wafer 8 is maintained at a temperature of about 40 degrees Celsius, for example.

  Here, the flow control device receives a signal from the pressure sensor 14 (vacuum gauge) so that the helium gas pressure on the back surface 28b of the semiconductor wafer 28 becomes a constant value (for example, about 1 kiloPa (Pascal)). The time change of the flow rate is stored and monitored by the manufacturing device control system 27 in response to a signal from the flow rate control device 1. And, for example, as shown in FIG. 28, when the wafer 28 is not normally attracted to the wafer holder 47 due to the foreign matter 62 or the like, the flow rate of the cooling gas and its change over time show abnormal values. This abnormality is detected by the manufacturing apparatus control system 27. However, if the flow rate control valve 7 in the mass flow controller 1 (for example, FIG. 1) has a large leak at the time of closing, the value is lower than the flow rate of the cooling gas stored by the manufacturing apparatus control system 27, so an abnormality is detected. Will not be. That is, in reality, a larger amount of cooling gas is flowing than intended due to leakage at the time of closing the flow control valve 7, but the stored flow data of the cooling gas shows a smaller value.

  Therefore, it is effective to apply the leak check during closing of the flow control valve 7 as described above to the flow control device 1 (mass flow controller) in such a portion. The timing of the leak check when the flow rate control valve 7 is closed may be executed during the dry etching process for the preceding wafer (first wafer) and the next wafer (second wafer) in the batch. Good. The processing may be performed between all wafer processing, but may be performed every few wafers or once to several times within a batch. Further, even between batches, it may be executed during the dry etching process for the last wafer (first wafer) of the preceding batch and the first wafer (second wafer) of the next batch. In general, the leak check when the flow control valve 7 is closed may be automatically executed while the flow control valve 7 is in the closed state.

  Here, based on the result of the leak check when the flow control valve 7 is closed, the set value of the flow control valve 7 may be automatically set to a value obtained by subtracting the leak. By doing in this way, the lifetime of the flow control valve 7 can be extended.

12 Explanation of defect generation mechanism in tungsten film formation (mainly FIGS. 27 and 28)
FIG. 27 is a schematic device cross-sectional view illustrating the mechanism of occurrence of defects in the process shown in FIG. FIG. 28 is a front sectional view of an etching apparatus for explaining a case where wafer adsorption is incomplete in the apparatus shown in FIG. Based on these, the failure occurrence mechanism in tungsten film formation will be described.

In the tungsten nucleation step 104 (FIG. 19) described in section 10, if the tungsten source gas (WF ₆ ) flow control device 1b has a leakage at the time of closing, the device may be defective. As shown in FIG. 27 (corresponding to the process step of FIG. 23), when the tungsten source gas is excessively supplied at the initial stage, the fluorine radical 61 precedes the hole bottom region R1, and the barrier metals 81 and 82 This is because is etched.

13. Summary As described above, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited thereto, and it goes without saying that various modifications can be made without departing from the scope of the invention. .

  For example, in the above-described embodiment, the example in which the opening / closing valve 12 and the pressure sensor are built in the flow control device has been specifically described. However, the present invention is not limited thereto, and the opening / closing valve is provided outside the flow control device. Needless to say, the present invention can also be applied to one or both of the pressure sensor 12 and the pressure sensor.

  Moreover, in the said embodiment, although the pneumatic valve was demonstrated concretely as an on-off valve, it cannot be overemphasized that an electromagnetic valve may be used for this invention, without being limited to it. Furthermore, in the above-described embodiment, the flow control valve has been described mainly using a piezo actuator, but the present invention is not limited thereto, and it goes without saying that another actuator may be used.

  Further, in the above embodiment, the semiconductor device manufacturing method has been specifically described by taking an example of supply of reactive gas in tungsten CVD and cooling gas control in dry etching of an aluminum-based wiring film. Needless to say, the present invention can be applied to a wafer surface treatment process, a wafer heat treatment process, and the like in addition to other CVD processes and etching processes. Needless to say, the present invention can be applied not only to the reactive gas or the cooling gas but also to the control of the carrier gas, the purge gas, and other additive gases.

1, 1a, 1b, 1c, 1d, 1e Flow rate control device (mass flow controller)
2 Process gas inlet 3 Process gas discharge port 4 Flow rate measurement flow path 5 Bypass flow path 6 Flow rate sensor 7 Flow rate control valve 8 Flow rate control circuit 9, 10 Resistance heating element 11 Gas discharge path (gas introduction path of wafer processing chamber)
12 Downstream open / close valve (pneumatic open / close valve)
13 Three-way switching open / close valve 14 Pressure sensor 15 Bridge circuit 16 Amplification correction circuit 17 Comparison control circuit 18 Detection data output terminal 19 Input terminal for setting value etc. 20 Vent line 21 Air pressure input port (air pressure control system)
22 Detection pressure external output terminal 23 Semiconductor manufacturing equipment 24 Gas constant pressure source 25 Gas inflow passage 26 Wafer processing chamber 27 Manufacturing equipment control system 28 Semiconductor wafer (P-type single crystal silicon substrate)
28a Semiconductor wafer surface (device surface)
28b Back surface of semiconductor wafer 29 Gate valve 30 Spindle valve 31 Gas inflow part of flow control valve 32 Gas discharge part of flow control valve 33 Metal diaphragm 34 Piezo effect actuator 35 Cylinder 36 Pneumatic chamber 37 Metal diaphragm 38 Seal resin ring 39 Piston 40 Seal ring installation part 41 Process gas inflow part of opening / closing valve 42, 42a, 42b, 42c, 42d, 42e Upstream opening / closing valve (pneumatic opening / closing valve)
43 Flow Control Surface 44 Output Side Cavity 45 Tungsten Thermal CVD Equipment 46 Shower Head 47 Wafer Holder (Wafer Stage)
48 Heater 50 Leak check start when closed 51a Reference pressure measurement 51b Ultimate pressure measurement 52 Calculation formula reference 53 Comparison judgment 54 Production continuation 55 Alarm generation 56 Replacement 57 Vacuum exhaust system (exhaust pipe)
58 Dry pump 59 Aluminum wiring etching system 60 Wafer back surface cooling gas system (cooling gas flow path)
61 Fluorine radical 62 Foreign matter or particle 71 STI buried insulating film (field insulating film)
72 N-type high-concentration source / drain region 73 N-type source / drain extension region 74 Gate insulating film 75 Gate electrode 76 Cap insulating film 77 Side wall spacer insulating film 78 Premetal insulating film 79 Contact hole 80 N-channel MISFET
81 Lower barrier metal film (titanium film) of plug part
82 Upper barrier metal film (titanium nitride film) of plug part
83 Tungsten film (tungsten plug)
91 Lower layer barrier metal film (titanium film) of wiring
92 Barrier metal film on wiring (titanium nitride film)
93 Main parts of aluminum wiring film 94 Cap metal film (titanium film)
95 Antireflection film (titanium nitride film)
96 Aluminum-based wiring film 101 Wafer introduction step 102 Gas introduction step 103 Wafer heating step 104 Nucleation step 105 Intermediate gas purge step 106 Embedded film formation step 107 Final gas purge step 108 Wafer discharge step 109 Leak check step A Mass flow controller central part B Wafer processing Gas flow path just before the chamber R1 Hole bottom area

Claims (24)

A semiconductor device manufacturing method including the following steps:
(A) introducing the first semiconductor wafer into the wafer processing chamber;
(B) executing wafer processing while introducing a reactive gas into the wafer processing chamber in a state where the first semiconductor wafer is introduced via a flow rate control device;
(C) after the step (b), discharging the first semiconductor wafer from the wafer processing chamber;
(D) a step of introducing a second semiconductor wafer into the wafer processing chamber after the step (c);
(E) executing the wafer processing while introducing the reactive gas into the wafer processing chamber in a state where the second semiconductor wafer is introduced via the flow rate control device;
(F) After the step (e), a step of discharging the second semiconductor wafer from the wafer processing chamber;
Here, the flow control device includes:
(P) a gas inlet, a gas outlet, and a gas flow path connecting them;
(Q) a flow rate measurement channel provided in the gas channel between the gas inlet and the gas outlet;
(R) a flow rate sensor provided in the flow rate measurement channel;
(S) a bypass flow path provided in parallel with the flow rate measurement flow path;
(T) a flow rate control valve provided on the gas discharge port side of the flow rate measurement channel and the bypass channel,
Here, the manufacturing method of the semiconductor device further includes the following steps:
(G) A step of detecting a gas leak state when the flow control valve in the flow control device is in a closed state after the step (b) and before the step (e).     In the method of manufacturing a semiconductor device according to the item 1, the wafer processing is a CVD process.     In the method of manufacturing a semiconductor device according to the item 2, the wafer processing is a CVD process of a tungsten film. In the method of manufacturing a semiconductor device according to the item 3, the wafer processing is a step of filling a tungsten plug.     In the method for manufacturing a semiconductor device according to the item 4, the detection of the gas leak state is automatically executed.     In the method of manufacturing a semiconductor device according to the item 5, when an abnormality is found as a result of detection of the gas leak state, an alarm is issued.     In the method of manufacturing a semiconductor device according to the item 1, when the gas leak state is detected as a result of the detection of the gas leak state in the step (g), the condition of the step (e) is changed.     In the method for manufacturing a semiconductor device according to the item 1, a valve for closing the bypass flow path is provided in the flow rate control device. With the bypass flow path closed, the flow rate measurement flow path The gas leak state is detected. In the method of manufacturing a semiconductor device according to the item 1, the flow control device further includes:
(U) a pressure sensor for measuring the pressure of the gas flow path between the flow control valve and the gas outlet;
Here, the detection of the gas leak state is performed using the pressure sensor. In the method of manufacturing a semiconductor device according to the item 9, the flow control device further includes:
(V) An open / close valve provided in the gas flow path between the pressure sensor and the gas discharge port and opened / closed in conjunction with opening / closing of the flow control valve.     In the method of manufacturing a semiconductor device according to the item 10, the volume of the gas flow path between the flow control valve and the opening / closing valve is 2 cc or less.     In the method of manufacturing a semiconductor device according to the item 10, the volume of the gas flow path between the flow control valve and the opening / closing valve is 1 cc or less. The method for manufacturing a semiconductor device according to the item 12, further includes the following steps:
(H) A step of detecting a gas leak state when the on-off valve is in a closed state after the step (b) and before the step (g).     In the method of manufacturing a semiconductor device according to the item 12, the flow control valve is driven by a piezo actuator.     In the method of manufacturing a semiconductor device according to the item 14, the open / close valve is driven by gas pressure.     In the method of manufacturing a semiconductor device according to the item 7, the change of the condition in the step (e) is the timing of introducing the gas into the wafer processing chamber according to the leak state of the gas in which the leak is detected. To change.     In the method of manufacturing a semiconductor device according to the item 16, the change in the introduction timing is a timing delay.     In the method of manufacturing a semiconductor device according to the item 7, the change of the condition in the step (e) is that the amount of the gas introduced into the wafer processing chamber is changed according to the leak state of the gas in which the leak is detected. To change.     In the method of manufacturing a semiconductor device according to the item 18, the change of the introduction amount is performed by subtracting the leased gas amount from a set value of the gas introduction amount. A semiconductor device manufacturing method including the following steps:
(A) introducing a semiconductor wafer into the wafer processing chamber;
(B) A step of performing wafer processing while intermittently or continuously introducing an inert gas into the wafer processing chamber in a state where the semiconductor wafer is introduced via a flow rate control device;
(C) after the step (b), discharging the semiconductor wafer from the wafer processing chamber;
Here, the flow control device includes:
(P) a gas inlet, a gas outlet, and a gas flow path connecting them;
(Q) a flow rate measurement channel provided in the gas channel between the gas inlet and the gas outlet;
(R) a flow rate sensor provided in the flow rate measurement channel;
(S) a bypass flow path provided in parallel with the flow rate measurement flow path;
(T) a flow rate control valve provided on the gas discharge port side of the flow rate measurement channel and the bypass channel,
Here, the manufacturing method of the semiconductor device further includes the following steps:
(G) A step of detecting a gas leak state when the flow control valve in the flow control device is in a closed state.     In the method of manufacturing a semiconductor device according to the item 20, the wafer processing is a dry etching process.     In the method for manufacturing a semiconductor device according to the item 21, the wafer processing is a dry etching process of an aluminum-based wiring film.     In the method for manufacturing a semiconductor device according to the item 22, the inert gas is a gas mainly containing helium for cooling the back surface of the semiconductor wafer.     In the method for manufacturing a semiconductor device according to the item 20, the detection of the gas leak state is automatically executed.

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