JP2006191151A - Method for manufacturing semiconductor device, and substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxide film formation technology and a method for manufacturing a semiconductor device, in which an oxide film can be formed at low temperatures in a short time. <P>SOLUTION: An oxidant supply unit 30 comprises an ozonizer 31 for producing ozone 32, a bubbler 34, wherein deionized water 35 is kept and an ozone supplying pipe 33 for supplying ozone 32 from the ozonizer 31 is immersed in the deionized water 35 so as to form ozone bubbles, and a supply pipe 36 for supplying an oxidant 37 which contains OH* produced by the ozone bubbles 32 and is connected to a feed pipe 18 of an oxide film forming apparatus 10. Since the oxidant which contains OH* produced by the ozone bubbles in water has a strong oxidizing power, an oxide film can be formed over a wafer at relatively low temperatures in a short time. Since this can be conducted without the use of a plasma, a semiconductor device or a circuit pattern formed previously on the wafer can be avoided from being damaged by plasma. The oxide film forming apparatus can be improved in the throughput, performance and reliability. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor device. For example, in a method for manufacturing a semiconductor integrated circuit device (hereinafter referred to as an IC), an oxide film that forms an oxide film on a semiconductor wafer (hereinafter referred to as a wafer) in which an IC is formed. The present invention relates to a technique effective for use in a film forming process, an etching process, a substrate surface cleaning process, a thin film forming process by CVD, and a cleaning process in a processing chamber.

In an oxide film forming process by thermal oxidation in a conventional IC manufacturing process, an oxide film is formed on a wafer by high-temperature heat treatment using oxygen (see, for example, Patent Document 1).
However, as ICs are highly integrated, the dimensions of semiconductor elements and circuit patterns have been miniaturized, and there is a concern that high-temperature heat treatment on the wafer may change the characteristics and materials of the semiconductor elements previously formed on the wafer. Therefore, it is desired to reduce the heat treatment temperature.
Under such a trend, ozone (O ₃ ) is considered promising as an oxidant that can lower the heat treatment temperature when forming an oxide film.
For example, the heat treatment temperature in the oxide film formation process using oxygen is as high as 700 to 1000 ° C., but in the oxide film formation process using ozone, an attempt is made to set the heat treatment temperature to 500 ° C. or less. Yes.
In addition, as an oxide film forming method for performing an oxide film forming process in a conventional IC manufacturing process at a low temperature of 500 ° C. or lower, a method of activating a reactive species or oxygen using plasma to oxidize a wafer is available. is there.

Japanese Patent Laid-Open No. 7-176498

In the method of forming an oxide film using ozone, a sufficient oxidation rate cannot be obtained at a low temperature, so the heat treatment temperature needs to be set to about 400 ° C. or higher.
However, at a heat treatment temperature of 400 ° C. or higher, ozone is decomposed, so that there is a problem that the oxidation effect by ozone is lost.
In other words, the oxidizing power of ozone is not strong enough to compensate for the lowering of the heat treatment temperature, and the appearance of a new oxidizing agent is awaited.

  In addition, in the oxide film forming method in which reactive species and oxygen are activated by using plasma to oxidize the wafer, the semiconductor element or circuit pattern previously formed on the wafer is damaged by the impact of the plasma. There is a problem.

  An object of the present invention is to provide an oxide film forming technique and a semiconductor device manufacturing method capable of forming an oxide film at a low temperature.

Representative inventions disclosed in the present application are as follows.
(1) carrying a workpiece into the processing chamber;
Forming a film on the object to be processed by alternately supplying a raw material gas and an oxidizing agent generated by bubbling ozone in a liquid containing at least hydrogen atoms into the processing chamber;
Unloading the object to be processed after film formation from the processing chamber;
A method for manufacturing a semiconductor device, comprising:
(2) In (1), the step of forming a film on the object to be processed includes supplying the source gas into the processing chamber;
Performing gas replacement in the processing chamber;
Supplying the oxidizing agent into the processing chamber;
Performing gas replacement in the processing chamber,
These steps are set as one cycle, and this is repeated a plurality of times.
(3) In (1), in the step of forming a film on the object to be processed, the source gas is adsorbed on the object to be processed by supplying the source gas into the processing chamber, and the oxidizing agent A method for manufacturing a semiconductor device is characterized in that the source gas adsorbed on the object to be processed and the oxidant are reacted to form a film on the object to be processed.
(4) a processing chamber for processing an object to be processed;
A heater for heating an object to be processed in the processing chamber;
An ozonizer that produces ozone;
A bubbler for generating an oxidant by bubbling ozone generated by the ozonizer in a liquid containing at least hydrogen atoms;
An oxidizing agent supply pipe for supplying the oxidizing agent generated in the bubbler into the processing chamber;
A source gas supply pipe for supplying source gas into the processing chamber,
The substrate processing apparatus, wherein the source gas supply pipe and the oxidant supply pipe are configured to alternately supply the source gas and the oxidant into the processing chamber.

In order to enable the formation of an oxide film at a low temperature, which is the problem described above, an oxidizing agent having sufficient oxidizing power even at a low temperature is necessary.
Therefore, the present inventors pay attention to OH ⁻ (hydroxyl ion) or OH * (hydroxyl radical), which is an oxidizing agent having the strongest oxidizing power in nature, and efficiently generates this OH * as an oxidizing agent. It has been found that the oxide film can be formed at a low temperature of 500 ° C. or lower by using it.

By the way, in order to dissolve ozone in water, bubbling of ozone into water is generally used.
However, the present inventors have investigated the fact that by bubbling ozone in water, OH * is generated and radicalized OH * is released into the atmosphere by bubbling.
As a reaction formula of ozone and water when bubbling ozone in water, the following formula (1) can be considered.
H ₂ O + O ₃ → 2OH * + 1/2 × O ₂ (1)
As another method for generating OH *, a method of mixing water vapor and ozone can be considered.
However, in this method, since the probability that water molecules in the gas phase and ozone collide and react is small, OH * cannot be efficiently generated.
Accordingly, the inventors of the present invention use a method of generating ozone by bubbling ozone in water to achieve more efficient generation of OH * and formation of an oxide film at a low temperature. did.

The present inventors use a gas generated by bubbling ozone into deionized water in order to investigate the oxidizing power of a gas containing OH * generated by bubbling ozone in water at a low temperature. Then, an experiment was conducted to form an oxide film on a silicon wafer as an object to be processed.
FIG. 1 shows an oxide film forming apparatus used in the experiment.
In FIG. 1, ozone 2 generated by the ozonizer 1 is bubbled in deionized water 3 in a bubbler 3A. A gas (hereinafter referred to as an oxidizing agent) 4 containing OH * generated by bubbling is introduced into a processing chamber 7 formed by a process tube 6 made of quartz through a supply pipe 5.
The processing chamber 7 is heated to 200 ° C., 300 ° C., 400 ° C., and 500 ° C. by a resistance heating type heater unit 8.
A silicon wafer 9 as an object to be processed is held by a holding table installed in the processing chamber 8.

FIG. 2 is a graph showing the relationship between the oxide film formation time and the thickness of the oxide film obtained by experiments.
In FIG. 2, the horizontal axis represents the oxide film formation time (time when the silicon wafer was exposed to the gas generated by bubbling ozone in deionized water) (minutes), and the vertical axis represents the oxide film film. Thickness (nm) is taken.
A solid broken line A indicates that when a gas generated by bubbling ozone into deionized water (hereinafter referred to as wet ozone) is introduced into a treatment chamber heated to 200 ° C., a broken broken line B indicates that the wet ozone is increased to 300 ° C. When introduced into a heated processing chamber, the broken line C indicated by the alternate long and short dash line indicates that the treatment chamber heated by wet ozone at 500 ° C. is indicated by the broken line D indicated by the two-dot chain line when heated ozone is introduced into the processing chamber heated to 400 ° C. Each case is shown in.
A point E indicated by □ (square) is compared with a point F indicated by 10 (cross) when non-bubbling ozone (hereinafter referred to as dry ozone) is introduced into a treatment chamber heated to 400 ° C. for comparison. For this reason, dry ozone is introduced into a treatment chamber heated to 500 ° C., respectively.

As apparent from FIG. 2, according to the case of the oxide film formation method using wet ozone, the oxide film formation method using dry ozone is less than 200 ° C., 300 ° C., 400 ° C., and 500 ° C. An oxide film formation rate of 6 to 4 times is obtained.
Therefore, a method for producing a semiconductor device, comprising: a step of generating an active gas by bubbling ozone in water; and a step of processing an object to be processed using the generated gas. According to the above, it has been demonstrated that an oxide film can be formed on an object to be processed at a lower temperature (at least at a temperature of about 200 to 500 ° C.) compared to the case of using dry ozone.

By the way, in the above experiment, a white deposit was observed near the exhaust port of the process tube made of quartz (SiO ₂ ) in the experimental apparatus of FIG. When this deposit was analyzed, it was found to be silicon oxide (SiO ₂ ) powder.
It is considered that the silicon oxide powder was deposited by etching the process tube with wet ozone and carrying it into the gas phase, where it was cooled in the non-heated part.
From this consideration, manufacturing a semiconductor device comprising: a step of generating an active gas by bubbling ozone in water; and a step of processing an object to be processed using the generated gas It has been determined that the method can etch silicon oxide.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows a batch type hot wall type oxide film forming apparatus (hereinafter referred to as an oxide film forming apparatus) in which an oxide film forming step in the semiconductor device manufacturing method according to the present invention is performed.
First, the oxide film forming apparatus 10 shown in FIG. 3 will be described.
The oxide film forming apparatus 10 includes a soaking tube 12 and a reaction tube (process tube) 13 that are arranged concentrically with each other and are supported perpendicularly to the housing 11.
The heat equalizing tube 12 disposed outside is made of a heat resistant material such as silicon carbide (SiC), and is formed in a cylindrical shape with the upper end closed and the lower end opened.
The reaction tube 13 disposed inside is made of a heat-resistant material such as quartz (SiO ₂ ) and is formed in a cylindrical shape with the upper end closed and the lower end opened, and the hollow portion of the cylinder forms the processing chamber 14. is doing. A plurality of air outlets 15 are opened on the ceiling wall of the reaction tube 13, and a diffusion portion 16 projects from the ceiling wall so as to cover the air outlet 15.
An upper end of the connecting pipe 17 is connected to the diffusion part 16, an intermediate part of the connecting pipe 17 is piped along the outer peripheral surface of the reaction pipe 13, and a lower end thereof is piped in the radial direction at the lower end part of the reaction pipe 13. Connected to the introduction pipe 18.
One end of an exhaust pipe 19 is connected to the lower end of the reaction tube 13, and the other end of the exhaust pipe 19 is connected to an exhaust device (not shown) including a pump or the like.

A heater unit 20 is disposed concentrically on the outside of the heat equalizing tube 12, and the heater unit 20 is supported vertically on the housing 11. The heater unit 20 is configured to heat the processing chamber 14 uniformly or with a predetermined temperature distribution throughout.
A thermocouple 21 for measuring the temperature of the processing chamber 14 is laid vertically inside the soaking tube 12 and outside the reaction tube 13 (between the soaking tube 12 and the reaction tube 13). The feedback control is performed based on the measurement result of the pair 21.

At the lower end opening of the reaction tube 13, for example, a base 22 formed in a disk shape by quartz is disposed, and the base 22 is in close contact with the lower end surface of the reaction tube 13 via a seal ring 23 to thereby form a processing chamber. 14 is hermetically sealed.
The base 22 is mounted on a seal cap 24 formed in a disk shape, and a rotation shaft 25 as a rotation mechanism is vertically inserted into the seal cap 24.
A heat insulating cap 26 is vertically installed on the base 22, and a boat 27 is vertically installed on the heat insulating cap 26.
The rotating shaft 25 is configured to rotate the heat insulating cap 26 and the boat 27. The boat 27 is configured to hold a large number of substrates to be processed, that is, wafers 29 in a state where the centers are aligned and horizontally disposed.
The seal cap 24 is configured to be lifted and lowered vertically by the boat elevator 28.

An oxidant supply device 30 for supplying an oxidant generated by bubbling ozone in deionized water (pure water) is connected to the introduction pipe 18 via a mass flow controller (MFC) 38 as a flow rate control means. Yes.
The oxidizer supply device 30 stores an ozonizer 31 that generates ozone 32 and deionized water 35, and an outlet of an ozone supply pipe 33 that supplies ozone 32 generated by the ozonizer 31 is in the deionized water 35. A bubbler 34 to be immersed and bubbled, and a supply pipe 36 for supplying an oxidant 37 containing OH * (OH radical) generated by bubbling ozone 32 in deionized water 35 from the bubbler 34 to the introduction pipe 18. And.
The bubbler 34 is provided with a heater 39 for heating the deionized water 35 in the bubbler 34, and the deionized water 35 can be heated by the heater 39 during bubbling.
The temperature of the deionized water 35 during bubbling is preferably room temperature, but may be room temperature or higher. For example, the temperature may be a boiling temperature.
In addition, as a liquid used for bubbling, deionized water (pure water) is particularly preferable.
Pure water is preferable because pure water has very few impurities, and ozone can be prevented from being consumed by impurities in water during bubbling, and OH radicals can be generated efficiently. It is. In addition, since there are few impurities, there is an advantage that a high-quality oxide film, that is, a film having good electrical characteristics and high stability can be formed.

The oxide film forming apparatus 10 includes a temperature controller 30A.
The temperature controller 30A is connected to the heater unit 20, the thermocouple 21, and the heater 39. The temperature controller 30A is configured so that the processing temperature when oxidizing the wafer is higher than the temperature of the deionized water 35 in the bubbler 34. Further, the heater unit 20 and the heater 39 are controlled so as to be 100 to 500 ° C.

The oxide film forming process in the IC manufacturing method according to the embodiment of the present invention by the oxide film forming apparatus according to the above configuration will be described below.
A silicon wafer (hereinafter referred to as a wafer) 29 on which an oxide film is to be formed is loaded (wafer charging) on the boat 27 by a wafer transfer device (not shown).
When the designated number of wafers 29 are loaded into the boat 27, the boat 27 is raised by the boat elevator 28 and loaded into the processing chamber 14 of the reaction tube 13 (boat loading).
When the boat 27 reaches the upper limit, the seal cap 24 and the base 22 are brought into close contact with the lower end portion of the reaction tube 13 via the seal ring 23 to close the reaction tube 13 in a sealed state. It will be in the state.
When closed hermetically, the processing chamber 14 is evacuated to a predetermined pressure by the exhaust pipe 19 and is heated by the heater unit 20 to a relatively low predetermined temperature as a method of forming an oxide film at 100 ° C. to 500 ° C.
At this time, the heater unit 20 is feedback-controlled by the controller 30A based on the measurement result of the thermocouple 21 so that the temperature in the processing chamber 14 becomes a predetermined temperature. Further, the heat insulating cap 26 and the boat 27 are rotated by the rotating shaft 25.

Subsequently, an oxidizing agent 37 containing OH * generated by bubbling ozone in deionized water is supplied from the oxidizing agent supply device 30 via the mass flow controller 38 via the introduction pipe 18 and the communication pipe 17 to the processing chamber 14. To be supplied. That is, the ozonizer 31 blows out ozone 32 from the outlet of the ozone supply pipe 33 into the deionized water 35 for bubbling.
When the ozone 32 is bubbled in the deionized water 35, the oxidant 37 containing OH * is generated according to the above-described equation (1) and is released into the space above the deionized water 35 in the bubbler 34. At this time, if it is deionized water 35, the reaction of the formula (1) occurs effectively.
At this time, the heater unit 20 and the heater 39 are controlled by the temperature controller 30A so that the treatment temperature is higher than the temperature of the deionized water 35 to be bubbled.
The oxidizing agent 37 released into the space above the deionized water 35 in the bubbler 34 is taken out from the bubbler 34 by the supply pipe 36 and supplied to the introduction pipe 18 through the mass flow controller 38. The oxidant 37 supplied to the introduction pipe 18 flows through the communication pipe 17 to reach the inner chamber of the diffusion section 16, diffuses in the inner chamber of the diffusion section 16, and blows out from the outlet 15 into the processing chamber 14 in a shower shape.
The oxidant 37 is supplied in a state controlled by the mass flow controller 38 so as to have a predetermined flow rate.

The oxidant 37 supplied to the processing chamber 14 contacts the wafer 29 while flowing down the processing chamber 14 by the exhaust force of the exhaust pipe 19, thereby forming an oxide film on the wafer 29.
At this time, since the boat 27 is rotating, the oxidant 37 contacts evenly in the plane of the wafer 29, so that the film thickness distribution of the oxide film formed on the wafer 29 becomes uniform in the plane.
Note that it is considered that either or both of the oxidation reaction and the thermal CVD reaction contribute to the formation of the oxide film.
Specifically, it is considered that the oxidation reaction is mainly performed for the first few minutes, and the remaining time is mainly CVD (deposition).

Here, since the oxidizing agent 37 supplied by the oxidizing agent supply device 30 contains OH * having a strong oxidizing power as described above, the processing temperature of the oxide film generation method is a relatively low temperature of 500 ° C. Even in the following cases, an oxide film can be formed on the wafer 29 at a high oxide film formation rate, and the oxide film can be formed in a short time.
If the processing temperature is higher than 500 ° C., the semiconductor elements and circuit patterns already formed on the wafer 29 are adversely affected. In addition, when the processing temperature is lower than 100 ° C., it is not preferable because neither an oxidation reaction nor a CVD reaction is likely to occur. Therefore, it is desirable to set the processing temperature to 100 ° C. or more and 500 ° C. or less.

  When a preset processing time elapses, the boat 27 is lowered by the boat elevator 28 so that the boat 27 holding the processed wafers 29 is unloaded from the processing chamber 14 to the original standby position (boat unloading). Is done.

  Thereafter, the above-described operation is repeated, and the wafers 29 are batch processed by the oxide film forming apparatus 10.

  According to the embodiment, the following effects can be obtained.

1. By bubbling ozone into water to produce an oxidant containing OH * and supplying this oxidant to the processing chamber, the processing temperature of the oxide film forming method can be relatively low, 500 ° C. or less. Since an oxide film can be formed on the wafer at a high oxide film formation rate, the oxide film can be formed on the wafer at a relatively low temperature in a short time.

2. By bubbling ozone into water to generate an oxidant containing OH *, OH * can be generated more efficiently than when OH * is generated by mixing water vapor and ozone. Realization of an oxide film forming method using OH * can be achieved.

3. OH * does not decompose even at temperatures as high as 400 ° C or higher like ozone, and oxidizers containing OH * exhibit strong oxidizing power even at temperatures of 400 ° C or higher at which a sufficient oxide film formation rate can be obtained. Therefore, an oxide film can be formed on the wafer in a short time at the highest temperature (eg, 500 ° C.) that does not adversely affect the semiconductor elements and circuit patterns previously formed on the wafer. Note that it is not preferable to perform the treatment at a temperature lower than 100 ° C. because an oxidation reaction and a CVD reaction are less likely to occur.

4). Ozone is bubbled into water to produce an oxidant containing OH *, and this oxidant is supplied to the processing chamber to form an oxide film. This eliminates the use of plasma, so it is formed on the wafer first. Further, it is possible to avoid plasma damage to the semiconductor element and the circuit pattern.

5. Through the above 1-4, the throughput, performance and reliability of the oxide film forming apparatus can be improved.

6). By bubbling ozone into deionized water that contains almost no impurities, it is possible to suppress consumption of ozone by impurities in the water during bubbling, thus effectively producing OH *. be able to. In addition, since there are few impurities, a high-quality film can be formed.

Next, an IC manufacturing method according to the second embodiment of the present invention will be described.
When the minimum processing dimension of an IC is 0.1 μm or less, in a gate process or a contact formation process, a substrate (wafer) as an object to be processed is used as a preprocessing step before a film forming process (step) which is the main process. It is necessary to continuously perform a substrate surface cleaning process (step) for removing the natural oxide film on the surface, the organic pollutant, and the metal pollutant.
The IC manufacturing method according to the present embodiment is characterized by this pre-processing step. That is, a method of carrying out a film forming process which is a main process by transferring a wafer from a load lock chamber to a cleaning unit and carrying out a pre-cleaning process and then continuously transferring the wafer to the CVD unit without taking it into the atmosphere. It is.

By the way, as a conventional cleaning apparatus for performing the pre-cleaning process in the contact formation step, there are a device for flowing a plasma-excited etching gas and a device for exciting an etching gas with ultraviolet rays.
However, when the aspect ratio of the contact pattern becomes large or the shape becomes complicated, in this type of conventional cleaning apparatus, the etching gas is consumed at the top of the hole, and it does not reach the bottom of the hole, or ultraviolet rays May not reach the bottom of the hall.
In addition, it is conceivable to set the pressure low and extend the mean free path of the active species to reach the bottom of the hole of the contact pattern with a high aspect ratio.
However, since plasma is not excited unless the pressure is relatively high, it cannot be employed.
On the other hand, the gas containing OH * generated by bubbling ozone in water according to the present invention has a low aspect ratio by setting the pressure low and extending the mean free path or increasing the partial pressure. Even a large contact pattern or a complicated contact pattern can reach the bottom.

  The IC manufacturing method according to the present embodiment includes a contact formation process performed by the multi-chamber apparatus shown in FIG. 4, and etching characteristics of a gas containing OH * generated by bubbling ozone into water. A pre-cleaning step (cleaning process) for removing a natural oxide film on the substrate surface, an organic contaminant causing substance, and a metal contaminant causing substance is used.

The multi-chamber apparatus 40 shown in FIG. 4 has a first wafer transfer chamber (hereinafter referred to as a negative pressure transfer chamber) configured in a load lock chamber structure that can withstand a pressure lower than atmospheric pressure (hereinafter referred to as a negative pressure). The housing 42 of the negative pressure transfer chamber 41 has a heptagonal shape in plan view and is formed in a box shape with both upper and lower ends closed.
A wafer transfer device (hereinafter referred to as a negative pressure transfer device) 43 for transferring the wafer 29 under a negative pressure is installed in the central portion of the negative pressure transfer chamber 41. It is composed of a SCARA robot (selective compliance assembly robot arm).

Of the seven side walls of the negative pressure transfer chamber housing 42, the side wall located on the front side has a carry-in spare chamber (hereinafter referred to as a carry-in chamber) 44 and a carry-out spare chamber (hereinafter referred to as a carry-out chamber). 45 are connected adjacently.
The casing of the carry-in chamber 44 and the casing of the carry-out chamber 45 are each formed in a box shape with a substantially rhombus in plan view and closed at both upper and lower ends, and are configured in a load lock chamber structure that can withstand negative pressure.
On the front side of the carry-in chamber 44 and the carry-out chamber 45, a second wafer transfer chamber (hereinafter referred to as a positive pressure transfer chamber) configured to maintain a pressure equal to or higher than atmospheric pressure (hereinafter referred to as positive pressure). 46) are connected adjacently, and the casing of the positive pressure transfer chamber 46 is formed in a box shape with a horizontally long rectangle in a plan view and closed at both upper and lower ends.
In the positive pressure transfer chamber 46, a wafer transfer device (hereinafter referred to as a positive pressure transfer device) 47 for transferring the wafer 29 under a positive pressure is installed. The positive pressure transfer device 47 is a SCARA robot. It is configured. The positive pressure transfer device 47 is configured to be moved up and down by an elevator installed in the positive pressure transfer chamber 46 and is configured to reciprocate in the left and right directions by a linear actuator.

A gate valve 48 is installed at the boundary between the carry-in chamber 44 and the positive pressure transfer chamber 46, and a gate valve 49 is installed at the boundary between the carry-out chamber 45 and the positive pressure transfer chamber 46. A notch aligning device 50 is installed on the left side of the positive pressure transfer chamber 46.
Three wafer loading / unloading ports 51, 52, 53 are arranged in the left-right direction on the front wall of the positive pressure transfer chamber 46, and the wafer loading / unloading ports 51, 52, 53 transfer the wafer 29 to the positive pressure. It is configured so that it can be carried into and out of the loading chamber 46. Pod openers 54 are installed at the wafer loading / unloading exits 51, 52, and 53, respectively.
The pod opener 54 includes a mounting table 55 for mounting the pod 57 and a cap attaching / detaching mechanism 56 for mounting and removing the cap of the pod 57 mounted on the mounting table 55, and the pod 57 mounted on the mounting table 55. The cap insertion / removal mechanism 56 attaches / detaches the cap to open / close the wafer inlet / outlet port of the pod 57.
A pod 57 is supplied to and discharged from the mounting table 55 of the pod opener 54 by an in-process transfer device (RGV) (not shown).

A first CVD unit 61, a second CVD unit 62, an annealing unit 63 and a cleaning unit 64 are connected adjacently to the four side walls located on the back side of the negative pressure transfer chamber housing 42.
The first CVD unit 61 and the second CVD unit 62 are constituted by a single wafer type CVD apparatus, and the annealing unit 63 is constituted by a single wafer type heat treatment apparatus.
The cleaning unit 64 performs a pre-cleaning step (cleaning process) that removes natural oxide films, organic contaminants, and metallic contaminants using the etching characteristics of gas containing OH * generated by bubbling ozone into water. As shown, it is configured as shown in FIG.

As shown in FIG. 5, the cleaning unit 64 includes a process tube 71 formed using a heat-resistant material having corrosion resistance such as quartz, and the process tube 71 is a processing chamber for cleaning the wafer 29. 72 is formed. The processing chamber 72 is provided with a holding base 73 for holding the wafer 29 horizontally.
A wafer loading / unloading port 74 is opened at the boundary between the process tube 71 and the negative pressure transfer chamber 41, and the wafer loading / unloading port 74 is configured to be opened and closed by a gate valve 75.
One end of an exhaust pipe 76 is connected to the process tube 71 so as to communicate with the processing chamber 72, and the other end of the exhaust pipe 76 is connected to an exhaust device (not shown) such as a vacuum pump.
A heater unit 77 for heating the processing chamber 72 is installed outside the process tube 71.
Connected to the process tube 71 is an etching gas supply device 80 that supplies a gas (hereinafter referred to as an etching gas) generated by bubbling ozone in deionized water to the processing chamber 72.
In the etching gas supply device 80, an ozonizer 81 that generates ozone 82 and deionized water 85 are stored, and an outlet of an ozone supply pipe 83 that supplies the ozone 82 generated by the ozonizer 81 is in the deionized water 85. A bubbler 84 that is immersed and bubbled and a supply pipe 86 that supplies an etching gas 87 containing OH * generated by bubbling ozone 82 in deionized water 85 to the processing chamber 72 are provided.
A mass flow controller (MFC) 88 is provided between the etching gas supply device 80 and the processing chamber 72 as flow rate control means for controlling the flow rate of the etching gas.
The bubbler 84 is provided with a heater 89 for heating the deionized water 85 in the bubbler 84, and the deionized water 85 can be heated when bubbling by the heater 89.
The temperature of the deionized water 85 during bubbling is preferably room temperature, but may be room temperature or higher. For example, the temperature may be a boiling temperature.

The cleaning unit 64 includes a temperature controller 80A.
A heater unit 77 and a heater 89 are connected to the temperature controller 80A. The temperature controller 80A is configured so that the processing temperature when cleaning the wafer is higher than the temperature of the deionized water 85 in the bubbler 84, and 50 The heater unit 77 and the heater 89 are controlled to be ˜400 ° C.

Hereinafter, the contact forming process in the IC manufacturing method using the multi-chamber apparatus having the above-described configuration will be described with a cleaning step as a main component.
The pod 57 is delivered from the in-process transfer device and placed on the placing table 55 of the pod opener 54.
The cap of the pod 57 is removed by the cap attaching / detaching mechanism 56, and the wafer loading / unloading port of the pod 57 is opened.
When the pod 57 is opened by the pod opener 54, the positive pressure transfer device 47 installed in the positive pressure transfer chamber 46 sequentially picks up the wafers 29 one by one from the pod 57 and loads them into the loading chamber 44 (wafers). Loading), and the 25 wafers 29 stored in one pod 57 are transferred to the temporary storage table for the loading chamber.
When the loading of the wafer 29 into the loading chamber 44 is completed, the gate valve 48 closes the loading chamber 44 and the loading chamber 44 is evacuated to a negative pressure by an exhaust device (not shown).

When the loading chamber 44 is depressurized to a preset pressure value, the loading port on the negative pressure transfer chamber 41 side is opened by the gate valve, and the wafer loading / unloading port 74 of the cleaning unit 64 is opened by the gate valve 75. .
Subsequently, the negative pressure transfer device 43 in the negative pressure transfer chamber 41 picks up the wafers 29 one by one from the loading chamber 44 and loads them into the negative pressure transfer chamber 41, and loads the wafers into the processing chamber 72 of the cleaning unit 64. The wafer is loaded (wafer loading) through the unloading port 74 and is transferred (set) onto the holding table 73 of the processing chamber 72. When the transfer of the wafer 29 to the holding table 73 is completed, the wafer loading / unloading port 74 of the cleaning unit 64 is closed by the gate valve 75.

When the processing chamber 72 is closed, the processing chamber 72 is evacuated to a predetermined pressure by the exhaust pipe 76, and the heater unit is controlled by the temperature controller 80A to a predetermined processing temperature of 50 ° C. to 500 ° C., preferably 50 to 400 ° C. 77 is heated.
Subsequently, an etching gas 87 containing OH * generated by bubbling ozone in deionized water is supplied from the etching gas supply device 80 to the processing chamber 72 via the mass flow controller 88. That is, the ozonizer 81 blows out ozone 82 from the ozone supply pipe 83 into the deionized water 85 and causes it to bubble.
At this time, the heater unit 77 and the heater 89 are controlled by the temperature controller 80A so that the treatment temperature becomes higher than the temperature of the deionized water 85 to be bubbled.
When the ozone 82 is bubbled in the deionized water 85, an etching gas 87 containing OH * is generated and discharged into the space above the deionized water 85 in the bubbler 84.
The etching gas 87 released into the space above the deionized water 85 in the bubbler 84 is taken out from the bubbler 84 by the supply pipe 86, controlled to have a predetermined flow rate by the mass flow controller 88, and supplied to the processing chamber 72.
The etching gas 87 supplied to the processing chamber 72 comes into contact with the surface of the wafer 29, thereby removing and cleaning (cleaning) a natural oxide film, an organic contaminant causing substance, and a metal contaminant causing substance formed on the surface of the wafer 29. To do.
Here, since the etching gas 87 supplied by the etching gas supply device 80 contains OH * having a strong oxidizing power as described above, a natural oxide film formed on the surface of the wafer 29 or an organic contaminant causing substance. In addition, metal contamination-causing substances can be removed by etching.
Note that a processing temperature lower than 50 ° C. or higher than 400 ° C. is not preferable because an etching reaction hardly occurs. Therefore, it is desirable to set the processing temperature for etching to a temperature of 50 ° C. or higher and 400 ° C. or lower.

When the cleaning process time set in advance in the cleaning unit 64 elapses and the cleaning is completed, the cleaned wafer 29 is transferred from the cleaning unit 64 to the negative pressure transfer chamber 41 maintained at a negative pressure by the negative pressure transfer device 43. Unload (wafer unloading).
When the cleaned wafer 29 is unloaded from the cleaning unit 64 to the negative pressure transfer chamber 41, the wafer loading / unloading port of the first CVD unit 61 is opened by the gate valve. Subsequently, the negative pressure transfer device 43 carries the wafer 29 carried out from the cleaning unit 64 into the first CVD unit 61.
When the transfer operation of the wafer 29 from the cleaning unit 64 to the first CVD unit 61 is completed, the first CVD unit 61 is closed by the gate valve.

Thereafter, in the first CVD unit 61, the processing chamber is hermetically closed and exhausted by an exhaust pipe so as to be at a predetermined pressure, heated to a predetermined temperature by a heater unit, and a predetermined source gas is introduced into the gas. By supplying a predetermined flow rate through the tube, a desired first film corresponding to a preset processing condition is formed on the wafer 29.
When a film formation process time set in advance in the first CVD unit 61 has elapsed, the wafer 29 on which the first film has been formed is picked up from the first CVD unit 61 by the negative pressure transfer device 43 and maintained at a negative pressure. It is carried out (wafer unloading) to the negative pressure transfer chamber 41.
When the processed wafer 29 is unloaded from the first CVD unit 61 to the negative pressure transfer chamber 41, the wafer loading / unloading port of the second CVD unit 62 is opened by the gate valve.
Subsequently, the negative pressure transfer device 43 carries the wafer 29 carried out from the first CVD unit 61 into the second CVD unit 62.

In the second CVD unit 62, a process similar to the process in the first CVD unit 61 is performed, whereby a second film is formed.
Thereafter, the wafer 29 on which the second film has been formed is transferred from the second CVD unit 62 to the annealing unit 63 via the negative pressure transfer chamber 41 by the negative pressure transfer device 43. In the annealing unit, annealing is performed in a predetermined atmosphere and a predetermined temperature.

  By repeating the above operation, the substrate surface cleaning process by the cleaning unit 64, the first film forming process by the first CVD unit 61, the twenty-five wafers 29 loaded in the loading chamber 44 at once, The second film forming process by the second CVD unit 62 and the thermal treatment by the annealing unit 63 are sequentially performed. When a series of predetermined processes are completed for the twenty-five wafers 29, the processed wafers 29 are returned to the empty pod 57.

  According to the embodiment, the following effects can be obtained.

1. Etching gas containing OH * generated by bubbling ozone in water can spread to the bottom even if the contact pattern has a large aspect ratio or a contact pattern with a complicated shape. A natural oxide film formed on the bottom surface of the contact pattern having a complicated shape, an organic contaminant causing substance, and a metallic contaminant causing substance can be reliably removed by etching.

2. Ozone is bubbled into water to generate an etching gas containing OH *, and this etching gas is supplied to the processing chamber, so that it is not necessary to use plasma, so semiconductor elements and circuit patterns previously formed on the wafer It is possible to avoid plasma damage to the like.

As a third embodiment of the present invention, a thin film such as a semiconductor oxide film (for example, SiO ₂ ) or a metal oxide film (for example, ZrO ₂ , HfO ₂ , Ta ₂ O ₅ ) is formed by thermal CVD reaction. There is an IC manufacturing method including a process.
The step of forming the thin film according to the present embodiment is performed by a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus 90 shown in FIG.
The MOCVD apparatus 90 shown in FIG. 6 includes a process tube 91 in which a processing chamber 92 is formed. A holding table 93 that holds the wafer 29 horizontally is installed in the processing chamber 92.
A wafer loading / unloading port 94 opened and closed by a gate valve 95 is opened on the side wall of the process tube 91, and an exhaust pipe 96 for exhausting the processing chamber 92 is connected to another position of the process tube 91.
A heater unit 97 for heating the processing chamber 92 is installed outside the process tube 91.
A raw material gas supply pipe 98 for supplying a raw material gas to the processing chamber 92 is connected to the process tube 91, and a vaporizer 99, a liquid flow rate controller 100, and a liquid raw material container 101 are connected to the processing chamber 92 side. It is interposed in order.
An oxidant supply device is connected to another position of the process tube 91.
Since this oxidant supply device is configured in the same manner as the oxidant supply device 30 in the first embodiment, the same reference numerals are given and description of the configuration is omitted.

In the present embodiment, a source gas (for example, a gas containing a semiconductor element or a gas obtained by vaporizing a liquid source containing a semiconductor element or a metal element) from the source gas supply pipe 98 and ozone are bubbled in water. By supplying the gas (oxidant) from the oxidant supply device 30 containing the generated OH * to the processing chamber 92 containing the wafer 29 and maintaining it at a predetermined temperature of 100 to 500 ° C. and a predetermined pressure. A CVD reaction is performed.
At this time, the heater unit 97 and the heater 39 are controlled by the temperature controller 30A so that the processing temperature becomes a predetermined temperature higher than the temperature of the deionized water 35 to be bubbled.
A semiconductor oxide film or a metal oxide film is formed on the wafer 29 by the CVD reaction between the source gas and the gas.

Examples of the source gas containing a semiconductor element used for forming a semiconductor oxide film such as SiO ₂ include silane-based gases such as SiH ₄ , Si ₂ H ₆ , SiH ₂ Cl ₂ , and SiCl ₆ .

In addition, as a liquid raw material containing a semiconductor element and a liquid raw material containing a metal element used for forming a semiconductor oxide film such as SiO _{2 and} a metal oxide film such as ZrO ₂ , HfO ₂ , Ta ₂ O ₅ ,
TEOS (tetraethoxylane (Si (OC ₂ H ₅ ) ₄ )),
BTBAS (Bisturary butylaminosilane (SiH ₂ (NH (C ₄ H ₉ )) ₂ )),
Si- (MMP) 4 (tetrakis (l-methoxy-2-methyl-2-propoxy) silicon _{(Si [OC (CH 3)} 2 CH 2 OCH 3] 4)),
Zr- (MMP) 4 (tetrakis (l-methoxy-2-methyl-2-propoxy) zirconium _{(Zr [OC (CH 3)} 2 CH 2 OCH 3] 4)),
Hf- (MMP) 4 (tetrakis (1-methoxy-2-methyl-2-propoxy) hafnium (Hf [OC (CH ₃ ) ₂ CH ₂ OCH ₃ ] ₄ )),
PET (pentaethoxytantalum (Ta (OC ₂ H ₅ ) ₅ ),
Tetrakis diethylamido hafnium (Hf [N (C ₂ H ₅ ) ₂ ] ₄ ),
Tetrakisdimethylamide hafnium (Hf [N (CH ₃ ) ₂ ] ₄ ),
Tetrakismethylethylamido hafnium (Hf [N (CH ₃ ) (C ₂ H ₅ )] ₄ ),
Tetrakis diethylamide silicon (Si [N (C ₂ H ₅ ) ₂ ] ₄ ),
Tetrakisdimethylamide silicon (Si [N (CH ₃ ) ₂ ] ₄ ),
Tetrakismethylethylamidosilicon (Si [N (CH ₃ ) (C ₂ H ₅ )] ₄ ),
Trisdiethylamide silicon (H—Si [N (C ₂ H ₅ ) ₂ ] ₃ ),
Trisdiethylamide silicon (H—Si [N (CH ₃ ) ₂ ] ₃ ),
Trismethylethylamide silicon (H-SiN (CH ₃ ) (C ₂ H ₅ )] ₃ )
Etc.

In addition, the processing temperature when processing the wafer is further lower than the temperature at which the CVD reaction occurs, and the source gas and the oxidizing agent (gas generated by bubbling O ₃ in water) are alternately supplied to the wafer. Thus, the film may be formed by an ALD (Atomic Layer Deposition) method.
In that case, the following reaction occurs on the wafer.
That is, by supplying the raw material gas onto the wafer at a temperature at which the raw material is not decomposed, the raw material gas is adsorbed (attached) on the wafer surface without being reacted. After that, by supplying an oxidizing agent (gas generated by bubbling O ₃ in water) to the wafer on which the raw material is adsorbed, the raw material adsorbed on the wafer surface reacts with the oxidizing agent, and on the wafer surface. A film is forcibly formed.
By repeating this, a film can be formed on the wafer one atomic layer at a time. At this time, it is preferable to provide a gas replacement step for purging or evacuating with an inert gas (N ₂ ) or the like between the source gas supply step and the oxidant supply step. That is, it is preferable to perform a cycle process in which (the source gas supply step → the gas replacement step → the oxidant supply step → the gas replacement step) is set to one cycle and this is repeated a plurality of times.

As a fourth embodiment of the present invention, there is an IC manufacturing method including a step of etching silicon oxide.
The etching apparatus in the present embodiment is configured similarly to the cleaning unit 64 in the second embodiment.
In the present embodiment, a gas (etching gas) containing OH * generated by bubbling ozone in water is supplied to the reaction chamber (etching chamber), and is predetermined at a predetermined temperature of 50 to 400 ° C. and a predetermined pressure. By keeping the time, SiO ₂ is etched.
Since the etching gas containing OH * generated by bubbling ozone in water has etching characteristics with respect to silicon oxide as described above, silicon oxide can be etched with a large selectivity.
Note that this embodiment can be applied to etching of a semiconductor film (for example, a silicon nitride film) or a metal film (for example, aluminum).

The etching reaction in the second embodiment and the fourth embodiment does not occur immediately even when a gas (etching gas) generated by bubbling O ₃ in water is supplied to a heated reaction chamber. It is considered that it is likely to occur in a certain excited state after an incubation period.
That is, a gas (etching gas) generated by bubbling O ₃ in water is supplied to the reaction chamber, and for a while, an etching reaction does not occur on the substrate (wafer), and an oxidation reaction occurs. After that, it is considered that an etching reaction occurs when a certain excited state is reached.
Although there is a range that overlaps the temperature range when the oxidation treatment is performed and when the etching treatment is performed (100 to 400 ° C.), in this temperature range, the treatment to be performed is determined by controlling the treatment time. You can do it.

In each of the above-described embodiments, the case where ozone is bubbled in deionized water to generate an active gas has been described. However, the liquid used for bubbling contains an OH group by bubbling ozone. Any liquid that can generate a substance, that is, OH radicals may be used, and any liquid that contains at least a hydrogen atom (H) may be used.
Further, it may be a liquid containing oxygen atoms (O), that is, a liquid containing at least hydrogen atoms (H) and oxygen atoms (O).
Further, it may be a liquid containing at least an OH group. For example, not pure water but simple water (H ₂ O) may be used.
Incidentally, hydrogen peroxide in addition to H ₂ O solution (H ₂ O ₂₎ and, when it is possible to use also hydrogen chloride (HCl) solution and the like is contemplated.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the gas generated by bubbling ozone into water can be applied to organic cleaning and sterilization of germs. Not only IC manufacturing methods, but also oxidation treatment in fields such as food manufacturing and medical treatment, etc. It can be applied to all cleaning processes.

It is a schematic diagram which shows the experimental apparatus for demonstrating the principle of this invention. It is a graph which shows the experimental result. It is side surface sectional drawing which shows the oxide film forming apparatus which is 1st embodiment of this invention. It is a partially-omission plane sectional view which shows the multi-chamber apparatus which is 2nd embodiment of this invention. It is side surface sectional drawing which shows the cleaning unit. It is side surface sectional drawing which shows the MOCVD apparatus which is 3rd embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Oxide film forming apparatus (substrate processing apparatus), 11 ... Housing, 12 ... Soaking tube (soaking tube), 13 ... Reaction tube (process tube), 14 ... Processing chamber, 15 ... Outlet, 16 ... Diffusion part, DESCRIPTION OF SYMBOLS 17 ... Communication pipe, 18 ... Introducing pipe, 19 ... Exhaust pipe, 20 ... Heater unit, 21 ... Thermocouple, 22 ... Base, 23 ... Seal ring, 24 ... Seal cap, 25 ... Rotating shaft, 26 ... Thermal insulation cap, 27 DESCRIPTION OF SYMBOLS ... Boat, 28 ... Boat elevator, 29 ... Wafer (object to be processed), 30 ... Oxidizer supply device, 31 ... Ozonizer, 32 ... Ozone, 33 ... Ozone supply pipe, 34 ... Bubbler, 35 ... Deionized water, 36 ... Supply pipe, 37 ... oxidizing agent (gas containing OH * generated by bubbling ozone in deionized water), 38 ... mass flow controller, 39 ... heater, 40 ... multi-chamber device (substrate) , 41 ... negative pressure transfer chamber (wafer transfer chamber), 42 ... negative pressure transfer chamber housing, 43 ... negative pressure transfer device (wafer transfer device), 44 ... loading chamber (preliminary for loading) Chamber), 45 ... unloading chamber (preliminary chamber for unloading), 46 ... positive pressure transfer chamber (wafer transfer chamber), 47 ... positive pressure transfer device (wafer transfer device), 48, 49 ... gate valve, 50 ... Notch aligner, 51, 52, 53 ... Wafer loading / unloading port, 54 ... Pod opener, 55 ... Mounting table, 56 ... Cap attaching / detaching mechanism, 57 ... Pod (substrate carrier), 61 ... First CVD unit, 62 ... First Two CVD units, 63 ... Annealing unit, 64 ... Cleaning unit, 71 ... Process tube, 72 ... Processing chamber, 73 ... Holding table, 74 ... Wafer loading / unloading port, 75 ... Gate valve, 76 ... Exhaust pipe, 77 ... Heater unit 80 ... Etching 81 ... Ozonizer, 82 ... Ozone, 83 ... Ozone supply pipe, 84 ... Bubbler, 85 ... Deionized water, 86 ... Supply pipe, 87 ... Etching gas (generated by bubbling ozone in deionized water) Gas), 88 ... mass flow controller, 89 ... heater.

Claims (4)

Carrying the workpiece into the processing chamber;
Forming a film on the object to be processed by alternately supplying a raw material gas and an oxidizing agent generated by bubbling ozone in a liquid containing at least hydrogen atoms into the processing chamber;
Unloading the object to be processed after film formation from the processing chamber;
A method for manufacturing a semiconductor device, comprising: In claim 1, the step of forming a film on the object to be processed includes the step of supplying the source gas into the processing chamber;
Performing gas replacement in the processing chamber;
Supplying the oxidizing agent into the processing chamber;
Performing gas replacement in the processing chamber,
These steps are set as one cycle, and this is repeated a plurality of times.   2. The method according to claim 1, wherein in the step of forming a film on the object to be processed, the source gas is adsorbed on the object to be processed by supplying the source gas into the processing chamber, and the oxidizing agent is used for the processing. A method of manufacturing a semiconductor device, comprising: forming a film on an object to be processed by reacting the oxidant with the source gas adsorbed on the object to be processed by being supplied indoors. A processing chamber for processing the workpiece;
A heater for heating an object to be processed in the processing chamber;
An ozonizer that produces ozone;
A bubbler for generating an oxidant by bubbling ozone generated by the ozonizer in a liquid containing at least hydrogen atoms;
An oxidizing agent supply pipe for supplying the oxidizing agent generated in the bubbler into the processing chamber;
A source gas supply pipe for supplying source gas into the processing chamber,
The substrate processing apparatus, wherein the source gas supply pipe and the oxidant supply pipe are configured to alternately supply the source gas and the oxidant into the processing chamber.

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