1. Technical Field
The present invention relates to a substrate processing apparatus for forming a desired thin film on a surface of a semiconductor wafer (called a wafer hereunder) and a manufacturing method of the semiconductor device and a forming method of a thin film, and particularly relates to a gas supply technique.
2. Background Art
Generally, in a vertical batch-type substrate processing apparatus, a throughput is improved by supporting a plurality of wafers in a boat and loading a boat into a substrate processing chamber. In addition, the boat is rotated around an axial center of the processing chamber, with the boat loaded into the processing chamber, and each wafer is rotated to uniformly flow a source gas on a film formation surface of the wafer, thus realizing uniformity in the in-surface film thickness for film formation.
However, even when a substrate processing gas is uniformly flown on the surface of the wafer by rotation of the wafer, non-uniformity sometimes occurs in the in-surface film thickness of the wafer. Therefore, a technique of realizing the uniformity of the in-surface film thickness for film formation is desired, which is not apply only to the batch-type substrate processing apparatus, and an object of the present invention is to solve such a problem.
In order to achieve the aforementioned object, the present invention includes a processing chamber that houses a plurality of substrates in a state of being stacked; a heating member that heats the substrate and an atmosphere in the processing chamber; a first gas supply member that supplies a source gas which self-decomposes at a temperature of the atmosphere in the processing chamber; a second gas supply member that supplies an oxidative gas; an exhaust member that exhausts the atmosphere in the processing chamber; and a controller that controls at least the first gas supply member, the second gas supply member, and the exhaust member, the first gas supply member further including at least one first inlet opening that introduces the source gas to the processing chamber so that the first inlet opening is opened in an appearance of avoiding a direction of the substrata housed in the processing chamber, and the second gas supply member further including at least one second inlet opening that introduces the oxidative gas into the processing chamber so that the second inlet opening is opened directed in a direction of the substrate housed in the processing chamber, and the controller controlling the first gas supply member, the second gas supply member, and the exhaust member, so that the source gas and the oxidative gas are alternately supplied and exhausted to produce a desired film on the substrate.
According to the present invention, it is possible to exhibit an excellent advantage that the in-surface film thickness of the substrate can be made uniform for film formation, which is not only apply to the vertical type substrate processing apparatus.
An embodiment of the present invention will be explained hereunder, with reference to the drawings.
As shown in
When the pod 110 is transferred from the in-step transport carriage to the load port 114, and the pod transport device 118 is moved to a pod reception position of the load port 114, the pod 110 is taken up from the load port 114 by the pod transport device 118. The pod 110 is automatically transported to a designated shelf 107 of the pod storing shelf 105, and thereafter is temporarily stored therein or is directly transported to the pod opener of a transfer chamber 130 side.
The transfer chamber 130 has a hermetically sealed structure fluidly isolated from a setting part of the pod transfer device 118 and the pod storing shelf 105, and a clean unit 134 composed of a supply fan and a dust-proof filter is provided therein so as to supply clean air, being a cleaned atmosphere or an inert gas. An oxygen concentration of the transfer chamber 130 is set at 20 ppm or less which is significantly lower than the oxygen concentration inside the casing 111 (air atmosphere).
A wafer transfer mechanism 125 is composed of a wafer transfer device (substrate transfer device) 125a and a wafer transfer device elevator (substrate transfer device elevating mechanism) 125b that elevates the wafer transfer device 125a. The wafer transfer device 125a transfers the wafer 200 between the pod 110 and a boat (substrate holding tool) 217 by a tweezer as a substrate holder.
A cap of the pod 110 is detached by a cap attachment/detachment mechanism of the pod opener, in a state that the wafer charging/discharging opening (not shown) is pressed against an opening edge portion of the wafer loading/unloading opening (not shown), to open the wafer charging/discharging opening of the pod 110. Next, the wafer transfer device 125a sequentially picks up the wafer 200 through the wafer charging/discharging opening of the pod 110 by the tweezer, so that a circumferential position, with a notch set as a reference, is matched by a notch aligning apparatus (not shown) as a substrate matching apparatus to match the circumferential position. Thereafter, the wafer 200 is charged into the boat 217 installed in a boat standby part 140 in the transfer chamber 130.
The boat 217 is supported on a seal cap 219 on a boat elevator 115 installed in the boat standby part 140 in a rear part of the casing 111, and is inserted from a lower side of a furnace orifice of a processing furnace 202 set in an upper part of the boat standby part 140. This processing furnace 202 is closed by a furnace orifice shutter 147 as a furnace orifice opening/closing mechanism, at the time other than the time of loading the boat 217.
When previously designated number of wafers 200 are charged into the boat 217, the furnace orifice of the processing furnace 202 closed by the furnace orifice shutter 147 is opened, and subsequently the boat 217 holding a wafer 200 group is loaded into the processing furnace 202 by an elevation of the boat elevator 115.
The boat 217 has a plurality of wafer holding members 131 and an elevating table 132 that supports these wafer holding members 131, so that the wafer 200 is horizontally inserted in a groove-shaped support 133 provided in multiple stages vertically spaced apart in a plurality of wafer holding members 131. When the wafer 200 is supported by each support 133, a plurality of wafers 200 are vertically arranged, with a center of the wafer aligned. In addition, each wafer 200 is horizontally held by the support 133 respectively. Note that about 50 to 125 sheets of wafers 200 are charged into the boat 217. After being loaded, the wafer 200 is subjected to an arbitrary substrate processing in the processing furnace 202. After substrate processing, in a reversed procedure to the aforementioned procedure excluding the step of matching the wafer 200 by the notch aligning apparatus, the wafer 200 and the pod 110 are discharged to outside of the casing 111.
In addition, the clean air blown out from the cleaning unit 134 is flown to the notch aligning apparatus, the wafer transfer apparatus 125a, and the boat 217 of the boat standby part 140, and thereafter is sucked by a duct 134a, which is then exhausted to the outside of the casing 111 or is circulated to a primary side (supply side), being the side of sucking the clean unit 134, and is blown out into the transfer chamber 130 again by the clean unit 134.
The processing furnace 202 will be described in detail, with reference to
The manifold 209 is opened facing a lower part, and a furnace orifice of the processing furnace 202 is extended downward. Specifically, the boat 217 is supported in a center of a boat support table 218 fitted to a tip end portion of a rotary shaft (not shown) vertically penetrating the axial center of the seal cap 219, the rotary shaft is fitted to a lower part of the seal cap 219, and the seal cap 219 is connected to a boat rotation mechanism 267 that transfers a rotation driving force as a fixing system. When the boat rotation mechanism 267 is driven, the rotary shaft is rotated and the boat 217 is rotated accordingly via the boat support table 218. Therefore, each wafer 200 is brought into contact with the atmosphere of the source gas and the oxidative gas supplied to the processing chamber 201 inside of the reaction tube 203. Thus, a uniform environment is obtained in the in-surface film thickness.
When explanation is given to a substrate processing gas supply system of the source gas and the oxidative gas, etc, with reference to
Then, the first gas supply tube 232a is jointed with the first carrier gas supply tube 234a, and a first mass flow controller (fluid controller) 240, being a flow rate control device, a vaporizer 242, and a first valve 243a, being an opening/closing valve, are sequentially provided from the upper stream side to the lower stream side, a second valve 243c, being the opening/closing valve is provided on the upper stream side of the jointed point of the first gas supply tube 232a and the first carrier gas supply tube 234a, and a second mass flow controller (flow rate control device) 241b is provided on the upper stream side of the second valve 243c.
In addition, the second gas supply tube 232b is jointed with the second carrier gas supply tube 234b for supplying the carrier gas, and in the second gas supply tube 232b, a third mass flow controller 241a and a third valve 243b, being the opening/closing valve, are provided from the upper stream side to the lower stream side, and in the second carrier gas supply tube 234b, a fourth valve 243d, being the opening/closing valve, is provided on the upper stream side of the jointed point of the second gas supply tube 232b and the second carrier gas supply tube 234b, and a fourth mass flow controller 241c, being the flow rate control device (flow rate control member) is provided on the upper stream side of the fourth valve 243d.
When the raw material supplied from the first gas supply tube 232a is a liquid, for example, the source gas supplied from the first mass flow controller 240, the vaporizer 242, and the first valve 243a is jointed with the carrier gas from the first carrier gas supply tube 234, which is then transferred to the first nozzle 233a by the carrier gas, and is supplied into the processing chamber 201 from the first gas supply hole 248a. When the raw material supplied from the first gas supply tube 232a is not liquid but gas, the first mass flow controller 240 is replaced with the mass flow controller for gas from the mass flow controller for liquid. In this case, the vaporizer 242 is not necessary.
In addition, the gas supplied from the second gas supply tube 232b is jointed with the carrier gas of the second carrier gas supply tube 234b via the third mass flow controller 241a and the third valve 243b, and is transferred to the second nozzle 233b by the carrier gas, and is supplied to the processing chamber 201 from the second gas supply hole 248b.
In addition, the processing chamber 201 is connected to a vacuum pump 246 as an exhaust member via a fifth valve 243e by the gas exhaust tube 231, being the exhaust tube for exhausting the gas, and is vacuum-exhausted. Note that the fifth valve 243e is capable of vacuum-exhausting the processing chamber 201 and stop of the vacuum-exhaust of the processing chamber 201 by opening/closing the valve, and further is constituted of the opening/closing valve capable of adjusting a pressure in the processing chamber 201 by adjusting the opening degree of the valve.
The controller 280 constituting a control part is connected to the first mass flow controller 240, the second to fourth mass flow controllers 241b, 241a, 241c, the first to fifth valves 243a, 243c, 243b, 243d, 243e, the heater 207, the vacuum pump 246, the boat rotation mechanism 267, an actuator such as the boat elevator 115, and a mechanism controller, and executes a flow rate adjustment of the first mass flow controller 240 and the second to fourth mass flow controllers 241b, 241a, and 241c, an opening/closing operation of the first to fourth valves 243a, 243c, 243b, 243d, opening/closing and a pressure adjustment operation of the fifth valve 243e, temperature adjustment of the heater 207 and start/stop of the vacuum pump 246, being an exhaust member, a rotation speed adjustment of the boat rotation mechanism 267, and elevating operation control of the boat elevator 115, and controls the film formation by CVD and ALD based on a recipe.
Next, as an example of the film formation processing by using the ALD method, explanation is given to a case of forming a HfO2 film by using TEMAH and O3.
The ALD (Atomic Layer Deposition) method, being one of the CVD (Chemical Vapor Deposition) method is a method whereby the reactive gas, being at lest two kinds of materials used in the film formation, is supplied onto the substrate alternately one by one, and is adsorbed on the surface of the film formation of the wafer 200 in units of one atom, and performs the film formation by using a surface reaction. At this time, control of the film thickness is performed by the number of cycles of supplying the reactive gas (for example, 20 cycles are performed for forming a film of 20 Å, when the film formation speed is set at 1 Å/cycle).
For example, when the HfO2 film is formed by the ALD method, TEMAH(Hf[NCH3C2H5]4) and tetrakis-methylethylaminohafnium), O3 (ozone) is used as the oxidative gas, to enable a high quality film formation to be performed at a low temperature of 180 to 250° C.
First, as described above, the wafer 200 is charged into the boat 217, and is loaded in the processing chamber 201. After the boat 217 is loaded into the processing chamber 201, three steps as will be described later are sequentially executed.
In step 1, TEMAH is flown to the first gas supply tube 232a as the source gas, and the carrier gas (N2) is flown to the first carrier gas supply tube 234a. All of the first valve 243a of the first gas supply tube 232a, the second valve 243c of the first carrier gas supply tube 234a, and the fifth valve 243e of the gas exhaust tube 231 are opened. The carrier gas is flown from the first carrier gas supply tube 234a and its flow rate is adjusted by the second mass flow controller 241b. The TEMAH (Tetrakis-Ethyl Methyl Amino Hafnium: tetrakis-Nethyl-Nmethylaminohafnium) is flown from the first gas supply tube 232a and its flow rate is adjusted by the first mass flow controller 240, being a liquid mass flow controller, and thereafter is vaporized by the vaporizer 242, which is then mixed in the carrier gas whose flow rate is adjusted, and as shown in
After the source gas is supplied, the first valve 243a of the first gas supply tube 232a is closed, and the supply of the TEMAH gas is stopped, to purge the surplus portion. At this time, the fifth valve 243e of the gas exhaust tube 231 is maintained to be opened, and the inside of the processing chamber 201 is exhausted (purged) until the pressure therein becomes 20 Pa or less by the vacuum pump 246 as a reduced pressure exhaust device, and a residual TEMAH gas is exhausted from the inside of the processing chamber 201. At this time, when the inert gas such as N2 is supplied into the processing chamber 201, efficiency in the exhaustion of the residual TEMAH gas is improved.
O3 is flown to the second gas supply tube 232b, and the carrier gas (N2) is flown to the second carrier gas supply tube 234b. Both of the third valve 243b of the second gas supply tube 232b and the fourth valve 243d of the second carrier gas supply tube 234b are opened. The carrier gas is flown from the second carrier gas supply tube 234b, and its flow rate is adjusted by the fourth mass flow controller 241c. O3 is flown from the second gas supply tube 232b, and is mixed in the carrier gas whose flow rate is adjusted by the third mass flow controller 241a, and is supplied into the processing chamber 201 from the second gas supply hole 248b by the carrier gas. At this time, the processing chamber 201 is continued to be exhausted by the vacuum pump 246 as an exhaust unit, and the surplus portion is exhausted from the gas exhaust tube 231. At this time, the fifth valve 243e is appropriately adjusted, and the inside of the processing chamber 201 is maintained to a prescribed pressure. The time required for exposing the wafer 200 to O3 is 10 to 120 seconds, and the temperature of the heater 207 is set, so that the temperature of the wafer 200 is maintained to a prescribed temperature from 180 to 250° C. in the same way as supplying the TEMAH gas of step 1. By the supply of O3, the surface reaction occurs between the raw material of TEMAH chemically adsorbed on the surface of the wafer 200 and O3, thus forming the HfO2 film on the wafer 200. After the film formation, the third valve 243b of the second gas supply tube 232b and the fourth valve 243d of the second carrier gas supply tube 234b are closed, and a gas atmosphere in the processing chamber 201 is vacuum-exhausted by the vacuum pump 246. By this exhaust, the gas after contributing to the film formation of the residual O3 is exhausted. However, at this time, when the inert gas such as N2 is supplied into the reaction tube 203, exhaust efficiency is largely improved, in exhausting the residual gas after contributing to the film formation of O3 from the processing chamber 201.
By setting the aforementioned steps 1 to 3 as one cycle, and repeating this cycle a plurality of times, the HfO2 film of a desired thickness is formed on the wafer 200.
Here, a comparative example is shown in
As shown in
Therefore, a special boat called a ring boat is used for the boat 217 in which three or four wafer holding members 131 are provided. However, it is difficult to solve the non-uniformity of the in-surface film thickness even by such a boat.
However, as shown in
When the mechanism of the result of
However, as is explained in this embodiment, when the direction of supplying the source gas from the first gas supply hole 248a is set as the direction of avoiding the side of the wafer 200, the TEMAH is supplied to the wafer 200 of the boat 217 only in the form of diffusion, thus making it difficult to generate a difference in film thickness by the flow of the TEMAH gas to each wafer 200, and a result is that the uniformity in the in-surface film thickness is improved.
Meanwhile, when the oxidative gas is examined, O3 is decomposed into O and O2, and reaction occurs between O and TEMAH intermediary body adsorbed on the surface of the wafer 200, to form Hf—O bond. However, when there is the TEMAH intermediary body, the reaction of O occurs, and when there is no TEMAH intermediary body, no reaction of O occurs and O is exhausted from the processing chamber 201. Therefore, almost no influence is applied on the uniformity of the in-surface film thickness, and if a fixed amount or more of O is supplied to the wafer 200, an entire surface for film formation of the wafer 200 is covered by O. Therefore, as shown in
Note that according to this embodiment, the number of the first gas supply hole 248a is set as one, and this gas supply hole 248a is set, so that the source gas is introduced in a direction of avoiding the direction of the wafer 200 side. However, a plurality of first gas supply holes 248a may be set, and by turning these first gas supply holes 248a in a direction other than the direction of the wafer 200, the raw materials in the TEMAH gas may be dispersed and adsorbed on the upper surface of each wafer 200, namely, on the film formation surface. In such a structure also, the source gas is adsorbed by dispersion and the in-surface film thickness of each wafer is made uniform.
Incidentally, when the HfO film is formed in the wafer 200 composed of silicon, by ALD using the substrate processing apparatus, the cycle of the following (1) to (7) is repeated to form the HfO film of a prescribed thickness, such as (1) the boat 217 is transferred to the wafer 200→(2) the boat 217 is inserted into the processing chamber 201 in which an atmosphere temperature is increased to 250° C.→(3) the atmosphere in the processing chamber 201 is exhausted (evacuated) by the vacuum pump 246 as an exhaust member→(4) mixed gas of the TEMAH gas and the carrier gas as the source gas is supplied from the first gas supply hole 248a (three minutes)→(5) the atmosphere in the processing chamber is exhausted by N2 purge (twenty seconds)→(6) O3 gas, being the oxidative gas, is supplied from the second gas supply hole 248b, to form the HfO film by a thermochemical reaction of Hf and adsorbed on the surface of the wafer 200→(7) the boat 217 is taken out from the processing chamber 201.
The TEMAH and O3 are alternately flown on the wafer 200, thereby forming the HfO2 film. However, the TEMAH, being the raw material of the ALD film formation, is decomposed from 120° C., and therefore not the HfO2 film but the metal Hf film is formed on an inner surface of the first nozzle 233a. Thus, during a repeated cycle of (1) to (7), generally particles are generated in a stage of a thin accumulated film thickness of HfO2 of the processing chamber 201 such as about 0.5 μm, with respect to 1 μm which is an index of the accumulated film thickness at the time of a regular maintenance.
Therefore, after processing the substrate, N2 gas is flown from the first nozzle 233a and the second nozzle 233b, respectively, and the particles in the gas are checked. Then, as shown in
Therefore, in order to remove the metal Hf film, being a deposit, use of a WET cleaning or Institu Cleaning (etching) is considered.
In a case of the WET cleaning, mixed solution of HF (Hydro Fluoric) and DIW (De Ionaized Water:pure) is used for the cleaning liquid. Before executing the Insitu Cleaning as a factor of experiment, HfO2 and a stuck material inside of the first nozzle 233a are infiltrated in the HF solution and an etching condition was examined. The HfO2 film was visually confirmed to be etched in the HF solution (25% of HF solution). An etching rate was 1000 A/min. However, as shown in
As shown in
Meanwhile, in the sequence according to the example 2, TEMAH gas, being the source gas, and O3, being the oxidative gas, are alternately flown to the TEMAH nozzle. Therefore, formation of the Hf-rich film is suppressed, and instead, the HfO2 film is formed.
An aspect of the present invention will be additionally described hereunder.
A substrate processing apparatus of the present invention includes:
a processing chamber that houses a plurality of substrates in a sate of being stacked;
a heating member that heats the substrate and an atmosphere in the processing chamber;
a first gas supply member that supplies a source gas that self decomposes at an atmosphere temperature in the processing chamber heated by the heating member;
a second gas supply member that supplies an oxidative gas;
an exhaust member that exhausts the atmosphere in the processing chamber; and
a controller that controls at least the first gas supply member, the second gas supply member, and the exhaust member,
the first gas supply member further including at least one first inlet opening for introducing the source gas into the processing chamber;
the first inlet opening being opened so as to avoid a direction of the side of the substrate housed in the processing chamber;
the second gas supply member further including at least one second inlet opening for introducing the oxidative gas into the processing chamber;
the second inlet opening being opened directed toward the side of the substrate housed in the processing chamber; and
the controller controlling the first gas supply member, the second gas supply member, and the exhaust member, so that the source gas and the oxidative gas are alternately supplied and exhausted so as to form a desired film on the substrate.
Here, the “stack” specifies an arrangement state of the wafers arranged, with a prescribed space sandwiched between the adjacent substrates, and the “prescribed space” means an interval allowing the source gas after thermal decomposition to be diffused. In addition, “the source gas and the oxidative gas are alternately supplied and exhausted to the processing chamber to form a desired film on the substrate” and this means the formation of the film on the substrate by alternately repeating the step of exhausting the source gas from the processing chamber after supplying the source gas into the processing chamber, and the step of exhausting the source gas from the processing chamber after the oxidative gas is supplied to the processing chamber.
Note that explanation has given to a case that the embodiment of the present invention is applied to a batch-type vertical substrate processing apparatus. However, the present invention is not limited thereto and also can be applied to a horizontal sheet-fed substrate processing apparatus.
Number | Date | Country | Kind |
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2006-257076 | Sep 2006 | JP | national |