JPH1128349A - Method and apparatus for vapor generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve an increase in the forming amt. of gas and the shortening of a vapor forming time by accelerating the flow velocity of gas for a vapor medium up to sound velocity and supplying a liquid to be evaporated into the accelerated gas to generate sudden shock waves and utilizing the energy of the shock waves at this time to form the liquid to be evaporated into a mist form. SOLUTION: A vapor generator 34 is equipped with an inflow port 50a to which carrier gas (N2 gas) being vapor medium gas is supplied and a medium- fine nozzle 50 having an outflow port 50b. The medium-fine nozzle 50 has a tapered nozzle part 51a gradually becoming narrow along the flow direction of the carrier gas and a fanwise nozzle part 51c gradually expanded along the flow direction from a throat part 51b being the narrowest part. A shock wave forming part 51 is formed on the side of the outflow part in the vicinity of the throat part 51b and a supply port 54 of IPD (isopropyl alcohol) as a liquid to be evaporated is opened to the fanwise nozzle part 51c in the vicinity of the throat part 51b and IPA is formed into a mist state by shock waves generated in the shock wave forming part 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for generating steam.

[0002]

2. Description of the Related Art For example, CVD (Chemical Vapor Deposition) which supplies a compound gas composed of elements constituting a thin film material onto an object to be processed such as a semiconductor wafer and forms a desired thin film by a chemical reaction on a gas phase or a wafer surface. Chemical Vapor
Deposition) technology, liquid to be vaporized such as IP
A drying technique for evaporating A (isopropyl alcohol) and bringing the vapor gas into contact with an object to be processed (an object to be dried) for drying is known. In these CVD techniques and IPA drying techniques, a steam generator is used to generate a material gas and a drying gas.

[0003] In the steam generator, a liquid to be vaporized is bubbled by using an ultrasonic wave or a carrier gas, and the gas is heated to a predetermined temperature to generate a gas, and the gas is supplied to a processing chamber together with a carrier gas. method,
For example, a gas to be vaporized is heated by heating a liquid to be vapor contained in a heating tank or an evaporating dish, transported using the vapor pressure of the gas, and a predetermined amount of gas is supplied into the processing chamber by a high-temperature mass flow controller. The vaporized liquid conveyed by the baking method or the pump is vaporized through the gap between the orifice part and the diaphragm surface,
A direct injection method or the like is employed in which a gas is generated by heating and the gas is supplied into a processing chamber.

[0004]

However, the bubbling method has many control factors for generating a predetermined gas, and requires strict temperature control to gasify the liquid to be vaporized. In addition, there is a problem that a large amount of carrier gas is required, and problems in quantitativeness and reproducibility are likely to occur in accordance with a change in consumption of the liquid to be vaporized (material). In addition, the baking method requires the use of the vapor pressure of the liquid to be vaporized (material) to control the flow rate using a high-temperature mass flow controller, and requires a certain amount of heating tank and evaporating dish, so the structure is complicated. In addition, the size becomes large, which increases the cost and limits the degree of freedom of the device design. In addition, this baking method has less control factors than the bubbling method, but because of the low vapor pressure material, the pressure generated even when heated is low, and it is difficult to obtain the pressure necessary for transfer, so that the stable transfer of steam is performed. There was also a problem that it was difficult to realize. In addition, the direct injection method is a method in which the liquid to be vaporized is transported in a liquid state, and is directly vaporized near the processing unit and the flow rate is controlled, so that the control factors are reduced as compared with the bubbling method and the baking method. Although it is possible to reduce the size of the apparatus, there is a problem that the use is limited because only a small amount of gas can be generated.

The present invention has been made in view of the above circumstances, and provides a steam generating method capable of easily generating gas with a small number of control factors, increasing the amount of gas generation and shortening the steam generation time. And an apparatus therefor.

[0006]

In order to achieve the above object, the invention according to claim 1 comprises a step of accelerating and increasing the flow velocity of a gas for a vapor medium to a sonic velocity; A step of supplying a liquid to be vaporized therein to suddenly generate a shock wave; and a step of atomizing the liquid to be vaporized by utilizing the energy of the generated shock wave.

According to a second aspect of the present invention, the method of the first aspect further comprises a step of heating the atomized liquid to be vaporized by a heating means.

According to a third aspect of the present invention, there is provided an inflow port and an outflow port for a gas for a vapor medium, a tapered nozzle portion having a narrow taper shape from the inflow port to the outflow port, and A small-diameter nozzle comprising a divergent nozzle portion having an expanding tapered shape toward an outlet, and a supply port for a liquid to be vapor opened toward the divergent nozzle portion of the small-diameter nozzle, I do.

According to a fourth aspect of the present invention, in the steam generator according to the third aspect, the liquid to be vaporized is disposed near or downstream of the divergent nozzle and the supply port of the liquid to be vaporized. Is further provided with a heating means for heating.

According to a fifth aspect of the present invention, in the steam generator according to the third aspect, a branch path connecting the gas inlet side and the gas outlet side, the inlet side and the outlet side. Pressure adjusting means interposed in the branch to adjust the pressure relationship with the side.

Preferably, the heating means includes a heating element having at least two or more heating capacities in a gas flow direction (Claim 6). It is preferable to change the heating capability of the body from dense to coarse along the gas flow direction (claim 7). Further, the heating means may include a plurality of heating elements having at least two or more heating capacities in the gas flow direction (claim 8). In this case, it is preferable to change the heating capacity of the plurality of heating elements from dense to coarse along the gas flow direction (claim 9). Also,
It is preferable that the plurality of heating elements have independently controllable heating capacities (claim 10).

Further, in the steam generator according to the third aspect, the supply port for the liquid to be vaporized may be opened in the divergent nozzle portion toward the divergent nozzle portion (claim 11). Further, the supply port of the liquid to be vaporized may be opened toward the divergent nozzle portion on an upstream side of the divergent nozzle portion.

[0013] In the steam generator according to the third aspect, it is preferable that a cooling means is provided in a vapor liquid supply pipe connected to the vapor liquid supply port (Claim 13).

According to this invention, when the gas for the vapor medium flows from the inlet to the outlet of the medium-thin nozzle, the gas is accelerated by the tapered nozzle portion and reaches the sonic speed at the narrow portion (throat portion). Even after entering the divergent nozzle portion, the pressure is further increased and increased by a large pressure difference to form a supersonic flow, which is jetted at a flow velocity higher than the sonic velocity. When the liquid to be vaporized is supplied from the supply port in such a state, a sudden shock wave is generated, and the energy of the shockwave is used to atomize the liquid to be vaporized. By heating the atomized liquid to be vaporized by the heating means, vapor can be generated (claims 1 to 4, 11, and 12).

Further, the gas inlet and the gas outlet of the small nozzle are connected by a branch path, and pressure adjusting means is provided in the branch path. The flow velocity of the gas flowing through the inside can be adjusted, and in response to the supply fluctuation of the carrier gas to the small and medium nozzles,
In addition, the conditions for generating the shock wave can be set as appropriate to correspond to a wide range of gas generation amounts.

Further, the heating means is formed of one or a plurality of heating elements having at least two or more heating capacities in the gas flow direction, and the heating capacity of the heating element is changed from dense to coarse along the gas flow direction. The temperature balance of the heating means can be corrected, the life of the heating means can be increased, and the decomposition and carbonization during gasification of the liquid to be vaporized can be prevented. To 8). Here, the decomposition carbonization means that the vaporized liquid, for example, IPA is decomposed and carbonized by being heated to a certain temperature or higher, and the carbonized component is attached by the heating means. Therefore, it is possible to reliably improve the reliability of the device.

Further, the heating means is formed of a plurality of heating elements having at least two or more heating capacities in the gas flow direction, and the heating capacities of the respective heating elements can be controlled with each other. Temperature balance can be reliably corrected, the life of the heating means can be prolonged, and the decomposition and carbonization during gasification of the liquid to be vaporized can be prevented (claims 9 and 10). Can be surely improved.

Further, by providing a cooling means in the vaporized liquid supply pipe connected to the vaporized liquid supply port, when the supply amount of the vaporized liquid is small, the vaporized liquid is supplied to the vaporized liquid before reaching the supply port due to the thermal influence from the heating means. Thus, the vaporized liquid can be prevented from evaporating, and the vaporized liquid can be reliably supplied to the supply port in a liquefied state.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, a case where the present invention is applied to a semiconductor wafer cleaning processing system will be described.

FIG. 1 is a schematic plan view showing an example of a cleaning processing system in which the steam generator according to the present invention is applied to a drying processing apparatus, and FIG. 2 is a schematic side view thereof.

The cleaning system includes a transfer section 2 for loading and unloading a container, for example, a carrier 1 for horizontally storing a semiconductor wafer W (hereinafter, referred to as a wafer) as an object to be processed, It mainly includes a processing unit 3 that performs a liquid process such as a cleaning liquid and a drying process, and an interface unit 4 that is located between the transfer unit 2 and the processing unit 3 and that performs transfer of the wafer W, position adjustment, and posture change. Have been.

The transport section 2 includes a carry-in section 5 and a carry-out section 6 which are provided alongside one end of the cleaning system. The carrier 1 of the loading unit 5 and the unloading unit 6
At the carry-in entrance 5a and the carry-out exit 6b, a slide-type mounting table 7 that allows the carrier 1 to enter and exit the carry-in section 5 and the carry-out section 6 is provided. In addition, the loading unit 5 and the unloading unit 6
A carrier lifter 8 (container transport means) is provided, and the carrier lifter 8 can transport the carrier 1 between the loading section and the unloading section, and the empty carrier 1 is provided above the transport section 2. The transfer to the carrier waiting unit 9 and the reception from the carrier waiting unit are performed (see FIG. 2).

The interface section 4 has a partition wall 4c.
A first chamber 4a adjacent to the loading section 5 and a loading section 6
And a second chamber 4b adjacent to the second chamber 4b. And
In the first chamber 4a, a horizontal (X, Y direction), a vertical direction (Z direction), and a rotatable (θ direction) wafer for taking out and transporting a plurality of wafers W from the carrier 1 of the loading unit 5 are provided. A take-out arm 10, a notch aligner 11 for detecting a notch provided on the wafer W, and an interval adjusting mechanism 12 for adjusting an interval between a plurality of wafers W taken out by the wafer take-out arm 10 are provided. First attitude converter 1 for converting wafer W to a vertical state
3 are provided.

In the second chamber 4b, a plurality of processed wafers W are received from the processing section 3 in a vertical state, and are transferred and transferred. 13A for converting the horizontal state from the vertical state to the horizontal state, and a plurality of wafers W that have been converted to the horizontal state by the second A wafer storage arm 15 that can be stored in the carrier 1 in a horizontal direction (X and Y directions), a vertical direction (Z direction) and a rotatable (θ direction) is provided. The second chamber 4b is sealed from the outside, and is configured so that the inside of the second chamber 4b is replaced by an inert gas (not shown), for example, N2 gas supplied from a supply source of nitrogen (N2) gas.

On the other hand, the processing section 3 includes a first processing unit 16 for removing particles and organic contaminants adhering to the wafer W, a second processing unit 17 for removing metal contaminants adhering to the wafer W, A cleaning / drying processing unit 18 and a chuck cleaning unit 19 for removing and drying the oxide film adhered to the wafer W are linearly arranged, and a transport path provided at a position facing each of these units 16 to 19. 20, X and Y directions (horizontal direction), Z
A wafer transfer arm 21 capable of rotating in a direction (vertical direction) and rotating (θ) is provided.

The washing / drying processing unit 18 is a
As shown in FIG. 3, an N2 gas heater 32 (hereinafter simply referred to as a heater) as N2 gas heating means connected to a supply source 30 of a carrier gas, for example, nitrogen (N2) gas via a supply path 31a, 32 through a supply path 31b, while a liquid for dry gas (liquid to be vaporized) such as IPA
A steam generator 34 according to the present invention connected to a supply source 33 via a supply path 31c, and a supply path 31d connecting the steam generator 34 and a drying processing chamber 35 (hereinafter simply referred to as a processing chamber). And a flow control means 36 provided.

In this case, the N 2 gas supply source 30 and the heater 3
An opening / closing valve 37a is interposed in the supply path 31a connecting the first and second valves. An opening / closing valve 37b is provided in a supply path 31c connecting the IPA supply source 33 and the heater 32, and a branch path 38 and an opening / closing valve are provided on the side of the opening / closing valve 37b on the side of the IPA supply source (steam supply source). IPA recovery unit 39 via valve 37c
Is connected. As shown by a two-dot chain line in FIG. 3, a drain pipe 40 of IPA is connected to the steam generator 34 as necessary, and a drain valve 41 is connected to the drain pipe 40.
And a branch path 40a with a check valve 42 interposed therebetween is connected. By connecting the drain pipe 40, the drain valve 41, and the like, the steam generator 34
This is convenient for discharging the cleaning liquid and the like when cleaning the inside.

As shown in FIG. 4, the steam generator 34 is provided with a supply path 3 for a carrier gas as a vapor medium gas.
It is provided with, for example, a stainless steel pipe-shaped small nozzle 50 having an inflow port 50a and an outflow port 50b connected to 1b. The medium-thin nozzle 50 has a tapered nozzle portion 51 that gradually narrows on the inner peripheral surface along the flow direction of the carrier gas.
a and a narrow portion (throat portion) of the tapered nozzle portion 51a
A divergent nozzle portion 51c that gradually expands in the flow direction from 51b, and a shock wave forming portion 51 is formed on the outlet side (secondary side) near the throat portion 51b.

Further, the throat portion 51b of the small-sized nozzle 50
In the vicinity of the divergent nozzle portion 51c, IP
A supply port 54 is opened, and I
An IPA supply source 33 as a vapor liquid supply source is connected through a PA supply pipe, that is, a supply path 31c.

In this case, as shown in FIG. 9, a flow control means 37d such as a pump may be provided in the flow control means supply passage 31c. With this configuration, the flow rate adjusting unit 37d can easily adjust the IPA flow rate supplied from the IPA supply source 33 to the shock wave forming unit 51 as necessary.

The outlet 50b of the divergent nozzle portion 51c
An inner cylinder heater 55 (heating means) as a first heating body is inserted into the small-diameter nozzle 50 on the side, and an outer cylinder heater 56 (heating means) as a second heating body is provided outside the first heating body. Thus, it is configured such that two or more stages of heating ability can be exhibited in the flow direction. That is, the heating capacity is configured to change from dense to rough along the flow of the carrier gas. In this case, a heater may be provided near the shock wave forming unit 51 and the IPA supply port 54.

A branch passage 52 is connected to the inlet 50a side and the outlet 50b side of the small nozzle 50, and a pressure regulating valve 53 is interposed in the branch passage 52. The adjustment is made so as to be able to cope with the fluctuation of the supply pressure of the carrier gas supplied to the small and medium nozzle 50. That is, since the orifice diameter of the small-diameter nozzle 50 is not variable but fixed, when the upper limit value is set for the primary-side (inlet side) pressure of the small-diameter nozzle, the flow rate of the carrier gas passing through the small-diameter nozzle 50 is also reduced. The upper limit is naturally set. However, if a higher carrier gas flow rate than the process conditions is required, such a branch 52
Is provided, and a carrier gas is introduced to the downstream side (outflow side) of the small-sized nozzle 50, whereby a wide range of flow rates can be supplied. In this case, the replenishment flow rate of the carrier gas can be adjusted by the pressure adjusting valve 53 provided in the branch passage 52. Further, the conditions for generating the shock wave can be appropriately set by adjusting the pressure adjusting valve 53.

If the inflow side pressure (primary side pressure) can be increased, the flow rate of the carrier gas increases in proportion thereto, so that it is not necessary to replenish the carrier gas particularly in the branch passage 53. That is, if it is possible to adjust the pressure or flow rate of the carrier gas (N2 gas) on the primary side in a predetermined high pressure range, shock waves can be formed without using the pressure adjusting valve 53. That is, as shown in FIG. 9, by connecting the N2 gas supply source 30 to the N2 gas pressure adjusting means 30a for adjusting the pressure or flow rate of the N2 gas, the branch passage 52 and the pressure adjusting valve 53 can be eliminated. . In this case, a predetermined high pressure range of N2
The N2 gas supply source 30 needs to be able to supply N2 gas at a higher pressure than usual so that gas can be supplied. By adjusting the degree of the pressure of the N2 gas supplied from the N2 gas supply source 30 by the N2 gas pressure adjusting means 30a, the pressure between the inflow pressure (primary pressure) and the outflow pressure (secondary pressure) of the shock wave forming section 51 is adjusted. By adjusting the difference, the conditions for generating the shock wave can be set as appropriate.

A cooling means 57 is provided in the IPA supply path 31c connected to the IPA supply port 54. The cooling means 57 supplies the refrigerant to the jacket surrounding the supply path 31c, for example, by circulating the coolant.
It is configured so that the IPA flowing inside c can be cooled below the boiling point. In this way, the cooling means 57
To prevent the IPA from evaporating due to the heat effect from the heating means, that is, the inner cylinder heater 55 and the outer cylinder heater 56 when, for example, supplying a very small amount of IPA. And IPA
Can be reliably supplied from the supply port 54 of the small-sized nozzle 50 in a liquid state.

With the above configuration, when the carrier gas (N2 gas), which is a gas for the vapor medium, flows from the inlet to the outlet of the small nozzle 50, the carrier gas is supplied by the tapered nozzle 51a. After being accelerated and reaching the sonic speed at the throat portion 51b, even after entering the divergent nozzle portion 51c, it is further expanded and accelerated by a large pressure difference to become a supersonic flow, and jets out at a flow speed higher than the sonic speed to generate a shock wave. . When IPA is supplied from the supply port 54 in such a state, a sudden shock wave is generated, and the energy of the shock wave is used to atomize the IPA. By heating the atomized IPA with the inner cylinder heater 55 and the outer cylinder heater 56, an IPA gas (steam) is generated. At this time, the heating capacity of the inner cylinder heater 55 and the outer cylinder heater 56 has at least two stages in the flow direction of the carrier gas, and the heating capacity is changed from dense to coarse along the flow direction of the carrier gas. Thus, the temperature balance between the inner cylinder heater 55 and the outer cylinder heater 56 can be corrected, and the life of the heaters 55 and 56 can be extended. In addition, it is possible to prevent excessive heating and prevent decomposition and carbonization of the IPA gas. That is, as shown in FIG. 5, when heating is performed by a heater having a uniform heating capacity, the heater surface temperature has a large gradient in the longitudinal direction (the flow direction of the carrier gas).

Further, for example, a thermocouple is installed in a heater,
When control is performed to maintain a constant temperature, the heater is energized to restore the temperature of the thermocouple, and the temperature balance in the longitudinal direction is further broken. This is heated as the carrier gas flows in the flowing direction. As a result, the temperature difference between the downstream heater portion and the carrier gas is reduced, heat exchange is suppressed, and the downstream heater portion is overheated. It is. On the other hand, the heaters 55 and 56 have the heating capability of the heaters 55 and 56 in at least two stages in the flow direction of the carrier gas, and change the heating capability from dense to coarse along the flow direction of the carrier gas. Surface temperature can be stabilized. Therefore, the heaters 55 and 56
Can be extended, and the decomposition and carbonization of the IPA gas can be prevented.

Further, as shown in FIG.
5 comprises a first inner cylinder heater 55a and a second inner cylinder heater 55b which can be controlled independently of each other.
It is also possible to comprise a first outer cylinder heater 56a and a second outer cylinder heater 56b which can be controlled independently of each other. The first inner cylinder heater 55a and the first outer cylinder heater 56a are arranged on the upstream side along the flow direction of the carrier gas, and the second inner cylinder heater 55b and the second outer cylinder heater 56b are arranged along the flow direction of the carrier gas. It is located downstream. First inner cylinder heater 5
5a, the heating capacity of the second inner cylinder heater 55b is reduced, and the heating capacity of the first outer cylinder heater 56a is increased.
Is configured so that the heating capacity of the heating element becomes small.

The first inner cylinder heater 55a and the second inner cylinder heater 5
5b and the first outer cylinder heater 56a and the second outer cylinder heater 56b are independently controlled, so that the surface temperatures of the heaters 55a, 55b, 56a, and 56b are increased along the flow direction of the carrier gas. It can be reliably controlled and stabilized to have a desired distribution. Therefore, the life of the heaters 55a, 55b, 56a, 56b can be increased, and the decomposition and carbonization of the IPA gas can be prevented. Note that the inner cylinder heater 55 and the outer cylinder heater 56 are not limited to being divided into two, and may be constituted by three or more parts that can be controlled independently of each other. Further, heating may be performed only by the inner cylinder heater 55 composed of a plurality of heater parts, or heating may be performed only by the outer cylinder heater 56 composed of a plurality of heater parts.

As shown in FIGS. 11A and 11B, a heater 140 can be used instead of the inner tube heater 55 and the outer tube heater 56. As shown in FIG. 11A, the heater 140 is provided in the shock wave forming section 5.
The spiral flow path 14 is inserted between the introduction pipe 143 communicating with the first pipe 1 and the inner wall of the introduction pipe 143.
4 and a flow path forming tube 14
The main part is constituted by a heating means, for example, a cartridge heater 146 inserted into the inside of 5.

In this case, the introduction pipe 143 has an inflow port 143a connected to the shock wave forming section 51 at one end, and an outflow port 143b connected to the supply path 31b at the other end. Further, the flow path forming tube 145 is formed as shown in FIG.
As shown in FIG. 7, a spiral concave / convex groove 147 such as a trapezoidal screw is formed on the outer peripheral surface of the spiral concave / convex groove 1.
47 and the inner wall surface 143c of the introduction tube 143
44 are formed. The spiral flow path 144 does not necessarily have to have such a structure.
43, a spiral groove is formed on the inner wall of
5 may be flat or the introduction pipe 14 may be flat.
A spiral channel may be formed by forming spiral concave and convex grooves on both the inner wall surface of No. 3 and the outer peripheral surface of the channel forming tube 145. As a heating unit, a heater for heating the outside of the introduction pipe 143 may be provided in addition to the cartridge heater 146.

In the above description, the case where the spiral passage 144 is formed by the introducer 143 and the passage forming tube 145 inserted into the introduction tube 143 has been described. A spiral flow path 144 may be formed by the pipe 143 and a coil-shaped member inserted into the introduction pipe 143, for example, a coil spring 45A. That is, the coil spring 45A is inserted into the introduction pipe 143, and the cartridge heater 146 is inserted into the coil spring 45A, so that the coil spring 45A interposed between the introduction pipe 45A and the cartridge heater 146.
A can form the spiral flow path 144.

As described above, the spiral flow path 144 is formed between the introduction pipe 143 connected to the shock wave forming section 51 and the flow path formation pipe 145 or the coil spring 45A inserted into the introduction pipe 143. By inserting the cartridge heater 146 into the flow path forming tube 145, the length of the flow path where the IPA gas flow path and the cartridge heater 146 are in contact with each other is increased, and a spiral flow is formed. As a result, the flow velocity can be increased as compared with the case where no heater is provided. As a result, the Reynolds number (Re number) and the Nusselt number (Nu number) are increased, the boundary layer is placed in the turbulent flow region, and the heat transfer efficiency of the heater 140 is improved. Can be planned. Therefore, the IPA gas can be efficiently heated to a predetermined temperature, for example, 200 ° C. by the cartridge heater 146, so that the size of the heater 140 can be reduced. If it is necessary to further increase the heating temperature, an outer cylinder heater may be provided outside the introduction pipe 143.

In this case, a shock wave can be formed by adjusting the pressure regulating valve 53, for example, by appropriately selecting the primary pressure (Kgf / cm2G) and the flow rate of N2 gas (Nl / min). For example, as shown in FIG. 6, the inner diameter of the throat portion 51c is 1.4 (mm), 1.7 (mm), 2.0 (mm).
(Mm), the N2 gas passage flow rate is 40 (Nl / mi
n), 60 (Nl / min), and 80 (Nl / min) generate a shock wave. The IPA concentration generated as described above is, for example, when the N2 gas flow rate is 100 (Nl / min),
IPA supply amount is 1 (cc / sec), 2 (cc / sec), 3 (cc / s)
ec), the IPA concentration was about 20% and about 30%, respectively.
(%), About 40 (%).

In the above-described embodiment, the medium-thin nozzle 50
The case where the IPA supply port 54 is provided at one position of the divergent nozzle part 51c of FIG.
As shown in (a), a plurality of pieces (four pieces are shown in the drawing) may be provided in the circumferential direction. Thus, the divergent nozzle 51
By providing a plurality of IPA supply ports 54 in the circumferential direction of c, it is possible to supply IPA evenly as compared with the case where a single IPA supply port 54 is provided, and it is possible to generate IPA vapor more efficiently.

As shown in FIG. 7 (b), the inflow port 50a side of the small-diameter nozzle 50 is bent into an elbow shape, and the opening at the tip end of the IPA supply pipe 31c penetrating this bent portion 50c is formed into a tapered nozzle portion. It may be arranged at the center of 51a and open toward the divergent nozzle portion 51c. By arranging the IPA supply pipe 31c in the tapered nozzle portion 51a and supplying the IPA to the tapered nozzle portion 51a, the carrier gas and the IPA are mixed, and the shock wave is generated as described above. The IPA may be atomized and steam may be generated by heating the heating means 55 and 56.

Here, the inflow port 5 of the small-sized nozzle 50
0a side is bent into an elbow shape, and IP
Although the A supply pipe 31c is made to penetrate, the small-diameter nozzle 50 and the IPA supply pipe 31c may be reversed. That is, as shown in FIG.
Elbow-shaped IP in the 0 tapered nozzle portion 51a
The A supply pipe 31c may be inserted so that the opening at the tip of the IPA supply pipe 31c is located at the center of the tapered nozzle 51a.

As shown in FIG. 7D, one end is open to the divergent nozzle portion 51c, and the other end is a tapered nozzle portion 51a.
A lateral L-shaped communication passage 58 that opens on the inflow side of the small nozzle 50 may be provided, and the communication passage 58 may be connected to the IPA supply pipe 31c that penetrates the bent portion 50c of the small nozzle 50. In this case, it is necessary to provide a hole 58a that penetrates the divergent nozzle portion 51c in processing the communication passage 58 into a lateral L shape, and it is necessary to close the outer opening of the through hole 58a with a plug 58b. There is. In FIG. 7, the other parts are the same as those in the above-described embodiment, and therefore, the same parts are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 3, the flow rate control means 36 comprises an opening adjustment valve, for example, a diaphragm valve 60 provided in the supply passage 31d, and a detection means for detecting the pressure in the processing chamber 35. A control unit for comparing and calculating a signal from a certain pressure sensor 61 with information stored in advance, for example, a CPU 62
(Central processing unit) and a control valve for controlling the operating pressure of the diaphragm valve 60 based on a signal from the CPU 62, for example, a micro valve 63.

On the other hand, as shown in FIG. 8, the processing chamber 35 stores (contains) a cleaning solution such as a chemical solution such as hydrofluoric acid or pure water and immerses the wafer W in the stored cleaning solution. The lid 71 is formed in an upper portion of the opening 70a for loading and unloading the wafer W provided above the opening 70a. Further, between the processing chamber 35 and the cleaning tank 70, a holding unit, for example, a wafer boat 72 that holds a plurality of, for example, 50 wafers W and moves the wafers W into the cleaning tank 70 and the processing chamber 35 is provided. Have been. Further, a cooling pipe 73 for cooling the IPA gas generated by the generator 34 and supplied into the processing chamber 35 may be provided in the processing chamber 35. The cleaning tank 70 includes an inner tank 75 having a discharge port 74 at the bottom, and an outer tank 76 for receiving the cleaning liquid overflowing from the inner tank 75. In this case, the wafer W is supplied to the chemical solution or pure water supplied and stored in the inner bath 75 from a chemical solution or pure water supply nozzle 77 disposed below the inner bath 75.
Is soaked and washed. A discharge pipe 76b is connected to a discharge port 76a provided at the bottom of the outer tank 76. With this configuration, the cleaned wafer W is moved into the processing chamber 35 by the wafer boat 72, and comes into contact with the IPA gas supplied into the processing chamber 35 to condense or adsorb the vapor of the IPA gas. Thus, the removal and drying of the water of the wafer W are performed.

The supply passage 31d is provided with a filter 80 at the downstream side (secondary side) of the diaphragm valve 60 so as to supply a dry gas with less particles. A heater 81 for keeping heat is provided outside the supply path 31d so that the temperature of the IPA gas can be kept constant.

Further, an I
A PA gas temperature sensor 90 (temperature detecting means) is provided to measure the temperature of the IPA gas flowing through the supply path 31dd.

Next, the operation of the above-mentioned drying apparatus will be described. First, after cleaning the wafer W carried into the cleaning tank 70 as described above, the wafer boat 72 is moved up to move the wafer W into the processing chamber 35. At this time,
The lid 71 of the processing chamber 35 is closed. In this state, the dry gas generated by the steam generator 34 by the N2 gas heated by the heater 32, that is, IPA
By supplying the gas into the processing chamber 35, the IPA gas and the wafer W come into contact with each other, and the vapor of the IPA gas is condensed or adsorbed, thereby removing and drying the moisture of the wafer W.

When the drying process is completed or immediately before the completion, the supply of IPA is stopped. During the drying, the exhaust may be exhausted from the discharge pipe 76b or the pressure may be reduced if necessary, and the inside of the processing chamber 35 may be lower than the atmospheric pressure. Therefore, a signal from the pressure sensor 61 for detecting the pressure in the processing chamber 35 is compared with information stored in advance by the CPU 62, and an output signal thereof is sent to the microvalve 63. The diaphragm valve 60 is operated by the control fluid, for example, air, and a small amount of N2 gas corresponding to the pressure in the processing chamber 35 is supplied into the processing chamber 35, and the atmosphere in the processing chamber 35 gradually changes from the state under the atmospheric pressure. Replaced with atmospheric pressure. Therefore, the processing chamber 35 after the drying process
The inside atmosphere does not suddenly change from the atmospheric pressure state to the atmospheric pressure state, so that adhesion of particles to the wafer W due to the winding-up can be prevented.

After the pressure in the processing chamber 35 has been replaced with the atmospheric pressure in this way, the lid 71 is opened, and the transfer arm (not shown) that has moved above the processing chamber 35 and the ascending wafer boat The transfer of the wafer W is performed between the wafer W and the wafer W. The transfer arm that has received the wafer W retreats from above the processing chamber 35 and transfers the wafer W to the interface unit 4.

In the above embodiment, the case where the steam generator according to the present invention is applied to a semiconductor wafer cleaning processing system has been described. However, the present invention can be applied to a processing system other than the cleaning processing, for example, a CVD thin film forming processing system. In this case, different types of organic source gas, high-dielectric-constant material source gas, and the like can be used depending on the gate insulating film, capacitor insulating film, interlayer insulating film, and the like to be formed.
For example, TEOS @ tetraethoxysilane (Si (OC2
H5) 4)}, TMP} trimethyl phosphate (PO (OCH
3) 3) {, TMB} trimethyl borate (B (OCH3)
3)} or PZT ｛Zirconium lead titanate (PbT
By using iO3) 材料 as a liquid to be vaporized, a thin film of a desired material can be formed. Further, it is needless to say that the present invention can be applied to an LCD glass substrate other than a semiconductor wafer.

[0056]

As described above, according to the present invention, the following excellent effects can be obtained.

1) According to the first to fourth, eleventh, and twelfth aspects of the present invention, the flow rate of the vapor medium gas is accelerated to a sonic speed and the speed is increased. Supplying and suddenly generating a shock wave, the energy of this shock wave is used to atomize the liquid to be vaporized, and then heated by the heating means to generate steam. The gas can be easily generated, and the amount of generated gas and the time for generating steam can be reduced.

2) According to the fifth aspect of the present invention, the gas inlet side and the gas outlet side of the medium-thin nozzle are connected by a branch path, and a pressure adjusting means is provided in the branch path. Therefore, in addition to the above 1), the flow rate of the gas flowing through the medium-thin nozzle can be adjusted by the pressure adjusting means, and the generation condition of the shock wave can be appropriately set to cope with a wide range of gas generation amount.

3) According to the invention of claims 6 to 8, the heating means is formed by a plurality of heating elements having at least two or more heating capacities in the gas flow direction. Since the temperature is changed from dense to coarse along the flow direction of the gas, it is possible to correct the temperature balance of the heating means in addition to the above 1), thereby increasing the life of the heating means and increasing the gasification of the liquid to be vaporized. In this case, decomposition carbonization can be prevented. Therefore, the reliability of the device can be improved.

4) According to the ninth or tenth aspect of the present invention, the heating means is formed by a plurality of heating elements having at least two or more heating capacities in the gas flow direction. Since the capacities are mutually controllable, in addition to the above 1), the temperature balance of the heating means can be reliably corrected, and the life of the heating means is increased, and the decomposition and carbonization during gasification of the liquid to be vaporized is prevented. can do. Therefore, it is possible to reliably improve the reliability of the device.

(5) According to the thirteenth aspect of the present invention, the cooling means is provided in the vaporized liquid supply pipe connected to the vaporized liquid supply port, so that the heating means is provided when the supply amount of the vaporized liquid is small. It is possible to prevent the liquid to be vaporized from evaporating due to the influence of heat from the liquid, and to reliably supply the liquid to be vaporized to the supply port in a liquefied state.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a cleaning processing system to which a steam generator according to the present invention is applied.

FIG. 2 is a schematic side view of the cleaning processing system.

FIG. 3 is a schematic configuration diagram of a drying processing apparatus including a steam generator according to the present invention.

FIG. 4 is a cross-sectional view showing one example of a steam generator according to the present invention.

FIG. 5 is a graph showing a temperature distribution between a heater serving as a heating unit and a heater having a uniform heating ability in the present invention.

FIG. 6 is a graph showing a relationship between a primary pressure and a flow rate of a drying gas in a steam generator.

FIG. 7 is a cross-sectional view showing another embodiment of the steam generator according to the present invention.

FIG. 8 is a schematic sectional view showing a processing chamber in the drying processing apparatus.

FIG. 9 is another schematic configuration diagram of a drying device including the steam generator according to the present invention.

FIG. 10 is a sectional view showing another example of the steam generator according to the present invention.

11A and 11B are a cross-sectional view showing another example of the heater of the steam generator according to the present invention and a partial cross-sectional view of a main part thereof.

FIG. 12 is a sectional view showing still another example of the heater of the steam generator according to the present invention.

[Explanation of symbols]

 Reference Signs List 30 N2 gas supply source (carrier gas supply source) 31c IPA supply path 33 IPA supply source (liquid supply source to be vaporized) 34 Steam generator 35 Processing chamber 50 Medium thin nozzle 50a Inlet 50b Outlet 51 Shock wave forming part 51a Tapered nozzle Portion 51b Throat portion (narrow portion) 51c Divergent nozzle portion 54 IPA supply port 55 Inner cylinder heater (heating body; heating means) 56 Outer cylinder heater (heating body; heating means)

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/304 361 H01L 21/304 361V

Claims (13)

[Claims] 1. a step of accelerating and increasing the flow velocity of a gas for a vapor medium to a sonic velocity, and a step of supplying a liquid to be vaporized into the accelerated gas to suddenly generate a shock wave; Using the energy of the generated shock wave to atomize the liquid to be vaporized. 2. The steam generating method according to claim 1, further comprising a step of heating the atomized liquid to be vaporized by a heating means. 3. An inflow port and an outflow port for a gas for a vapor medium, a tapered nozzle portion having a narrow taper shape from the inflow port to the outflow port, and expanding from the tapered nozzle portion to the outflow port. A steam generator, comprising: a small-diameter nozzle having an open-tapered divergent nozzle portion; and a supply port for a liquid to be vapor that opens toward the divergent nozzle portion of the small-diameter nozzle. 4. The steam generating apparatus according to claim 3, further comprising: a heating unit disposed near the divergent nozzle and the supply port for the liquid to be vapor or downstream thereof for heating the liquid to be vaporized. A steam generator further provided. 5. The steam generator according to claim 3, wherein a branch path connecting the gas inlet side and the gas outlet side, and a pressure between the inlet side and the outlet side. A pressure adjusting means interposed in the branch to adjust the relationship. 6. The steam generator according to claim 4, wherein said heating means includes a heating element having at least two or more heating capacities in a gas flow direction. 7. The steam generator according to claim 6, wherein the heating capacity of the heating element changes from dense to coarse along the gas flow direction. 8. The steam generator according to claim 4, wherein said heating means includes a plurality of heating elements having at least two or more heating capacities in a gas flow direction. 9. The steam generator according to claim 8, wherein the heating capacity of the plurality of heating elements changes from dense to coarse along the flow direction of the gas. 10. The steam generator according to claim 8, wherein the plurality of heating elements have independently controllable heating capacities. 11. The steam generator according to claim 3, wherein the supply port of the liquid to be vapor is opened in the divergent nozzle portion in the divergent nozzle portion. And a steam generator. 12. The steam generator according to claim 3, wherein the supply port of the liquid to be steamed opens toward the divergent nozzle at an upstream side of the divergent nozzle. A steam generator characterized by the above-mentioned. 13. The steam generating apparatus according to claim 3, wherein a cooling means is provided in a liquid supply pipe connected to the supply port of the liquid to be vaporized. .