JP2882963B2 - Steam generator for substrate processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam generator,
The present invention relates to a substrate processing vapor generator that generates vapor of a substrate processing liquid for processing various substrates such as a semiconductor substrate, a glass substrate for a photomask, and a glass substrate for a liquid crystal display element.

[0002]

2. Description of the Related Art For example, Japanese Patent Application Laid-Open No. 3-284842 discloses a substrate processing apparatus for performing a substrate processing such as etching or dissolving or removing metal impurities. The substrate processing apparatus includes a substrate processing liquid storage unit that stores a substrate processing liquid such as hydrogen fluoride, a substrate processing vapor generating unit that generates vapor of the substrate processing liquid, and a substrate holding unit that holds a substrate to be processed. Means, and a steam supply unit for supplying substrate processing steam from the substrate processing steam generation unit to the substrate held by the substrate holding means. The substrate processing liquid storage unit is provided with a hot water heater for heating the substrate processing liquid to a constant temperature and generating vapor of the substrate processing liquid, and the generated vapor is fed to the substrate processing vapor generation unit. For supplying nitrogen gas.

In this substrate processing apparatus, the substrate processing liquid stored in the processing liquid storage section is evaporated by heating by a hot water heater, and the vapor of the substrate processing liquid is generated in the substrate processing vapor generating section. This vapor is supplied onto the substrate by a nitrogen gas through a vapor supply unit. When the vapor is supplied onto the substrate, the oxide film on the substrate surface is dissolved and removed.

[0004]

In this type of substrate processing apparatus, a large amount of processing liquid which vaporizes during processing takes a large amount of heat of vaporization during processing, but the temperature of the processing liquid is low during non-processing because the amount of processing liquid vaporized is small. Hard to drop. Therefore, it is necessary to change the heat load from the hot water heater between processing and non-processing.
Further, since the storage area of the processing liquid is restricted, the heat exchange area of the hot water heater is restricted. For this reason, in the conventional configuration, the processing liquid temperature during the processing is not stable for several minutes to several tens of minutes after the substrate processing is started, the amount of generated steam varies, and the reproducibility of the substrate processing is deteriorated. Also, when the liquid level in the storage section is reduced due to the evaporation of the processing liquid, the amount of generated steam changes, and the reproducibility of the processing is reduced.

An object of the present invention is to improve the reproducibility of substrate processing by stabilizing the temperature of a processing solution during processing.

[0006]

According to the present invention, there is provided a vapor generating apparatus including a processing liquid storing section for storing a substrate processing liquid, a supply path, a vapor generating section, a processing liquid temperature adjusting means, and a reflux path. The supply path is for supplying the substrate processing liquid stored in the processing liquid storage unit to the vapor generation unit. The steam generator is
This is to vaporize the substrate processing liquid supplied by the supply path while overflowing the substrate processing liquid to generate vapor of the substrate processing liquid.
The processing liquid temperature adjusting means is provided in the middle of the supply path and adjusts the temperature of the processing liquid. The return path is for returning the substrate processing liquid overflowing in the vapor generating section to the processing liquid upstream of the processing liquid temperature adjusting means in the supply path or to the processing liquid storage section.

[0007]

In the steam generating apparatus according to the present invention, the substrate processing liquid stored in the processing liquid storing section is supplied to the steam generating section via the supply path. A processing liquid temperature adjusting unit is provided in the middle of the supply path, and the processing liquid passing therethrough is adjusted to a constant temperature by the processing liquid temperature adjusting unit. In the steam generating section, the processing liquid whose temperature has been adjusted to a certain temperature evaporates while overflowing. Then, the overflowing processing liquid is supplied to the supply path again or circulates directly or via the processing liquid storage unit.

Here, while circulating the substrate processing liquid,
The temperature of the processing liquid is adjusted by heating or cooling the processing liquid by the processing liquid temperature adjusting means, and the processing liquid is evaporated in the steam generating section, so that the temperature of the processing liquid is stabilized regardless of whether the processing is performed or not. As a result, the reproducibility of the substrate processing is improved.

[0009]

1, a substrate processing apparatus according to an embodiment of the present invention includes a substrate processing apparatus for processing a substrate by generating a vapor of, for example, hydrogen fluoride (HF) from a first vapor generator 9. Unit 1, a second vapor generation unit 2 for generating, for example, methyl alcohol vapor, a first processing liquid storage unit 3 for storing a processing liquid used in the substrate processing unit 1, and a second vapor generation unit 2 A second processing liquid storage unit 4 for storing the processing liquid,
The processing liquid stored in the first processing liquid storage unit 3 is transferred to the substrate processing unit 1.
And a second processing liquid supply unit 6 for supplying the processing liquid stored in the second processing liquid storage unit 4 to the second vapor generation unit 2. The apparatus further includes a gas supply unit 7 for supplying nitrogen gas to the substrate processing unit 1 and the second steam generation unit 2 and for supplying the steam generated in the substrate processing unit 1 and the second steam generation unit 2. ing.

The substrate processing section 1 includes a housing 8, a first steam generating section 9 disposed in the housing 8, and an inner housing 10 disposed in close contact with the lower surface of the first steam generating section 9.
And a substrate holding portion 11 rotatably arranged in the inner housing 10. The substrate holding unit 11 is provided with a substrate W
Stage 12 for holding the sample stage, a rotating shaft 13 for rotatably supporting the sample stage 12, and a belt-type transmission mechanism 13
and a motor M1 that is driven via the control signal a. The sample table 12 has a vacuum suction mechanism (not shown) for holding the substrate W by vacuum suction. Further, a heater (not shown) is embedded in the sample stage 12, so that the substrate W can be maintained at the same temperature or higher than the ambient temperature.

As shown in FIG. 2, the first steam generating section 9 has a dish shape, and is provided with a first container 15 having a weir 14 having a height of, for example, 5 mm formed around the first steam generating portion 9, and disposed around the first container 15. ,
Second container 1 containing processing liquid overflowing from first container 15
6. The bottom surface of the first container 15 is the second container 16
And the surface area of the first container 15 is sufficiently larger than the surface area of the second container 16. A lid 17 is disposed on these containers 15 and 16, and the lid 1
7, the space 2 surrounded by the containers 15, 16 and the lid 17
1 is hermetically sealed. The processing liquid vapor is generated in the space 21.

As shown in FIG. 1, the first steam generating section 9 detects the liquid level of the processing liquid in the second container 16.
A liquid level detector 93 including a bypass part 91 and a capacitance sensor 92 communicating with the second container 16 is provided. In the center of the first container 15, a processing liquid supply unit 1 recessed in a cylindrical shape is provided.
8 are arranged. At the upper end of the processing liquid supply unit 18, a jammer plate 19 having a plurality of nozzles around the processing liquid for smoothly supplying the processing liquid is arranged. In addition, the height of the weir 14 of the first container 15 is preferably 15 mm or less, more preferably in the range of 2 mm to 5 mm.

The lid 17 has a mounting hole 20 for a temperature sensor THP1 for measuring the temperature of the processing liquid stored in the first container 15, and a gas for supplying nitrogen gas for vapor pressure feeding to the space 21. A supply port 22 and a vapor discharge port 23 for discharging the vapor of the processing liquid generated in the space 21 are formed. In addition, on the bottom surface of the second container 16, a reflux port 24 for refluxing the processing liquid overflowing from the first container 15 is formed.

A steam space 25 for introducing the steam generated in the first steam generator 9 is formed on the lower surface of the steam generator 9. A steam inlet 26 for introducing steam is formed on a side wall of the steam space 25. Below the steam space 25, a perforated plate 27 for diffusing steam is arranged. The perforated plate 27 is disposed above the sample table 12 so as to face the same.

Openings 28 and 29 for inserting and removing the substrate W are formed in the inner housing 10 and the housing 8 at a level substantially equal to the upper surface of the sample table 12. The openings 28 and 29 are provided with shutters 30 and 31, respectively. These shutters 30, 3
1 can be opened and closed by motors M2, M3. Opening 29
A substrate transfer arm 34 (FIG. 4) for loading / unloading the substrate W is disposed outside the box. Substrate transfer arm 34
Sucks and holds the substrate W and carries it into the sample stage 12, and sucks and holds the substrate W on the sample stage 12 and discharges the substrate W out of the housing 8.

As shown in FIG. 3, the second steam generating section 2
A third container 35 having the same shape as the first container 15 and a fourth container 36 having the same shape as the second container 16 are provided. Third
A space 41 formed by the container 35 and the fourth container 36 and the lid 37 is hermetically sealed by the lid 37. At the center of the third container 35, a processing liquid supply unit 38 is arranged.
The processing liquid supply unit 38 is provided with a jammer plate 39 having a number of nozzles around the processing liquid for smoothly supplying the processing liquid.

The cover 37 has a mounting hole 40 for a temperature sensor THP3 for measuring the temperature stored in the third container 35.
In addition, a gas supply port 42 for supplying nitrogen gas for vapor pressure feeding to the space 41 and a vapor discharge port 43 for discharging vapor of the processing liquid generated in the space 41 are formed.
On the bottom surface of the fourth container 36, a reflux port 44 for refluxing the processing liquid overflowing from the third container 35 is formed.

As shown in FIG. 1, the second steam generator 2 is provided with a liquid level detector 96 comprising a bypass 94 and a capacitance sensor 95. As shown in FIG. 1, the first processing liquid supply unit 5 is configured to supply a processing liquid stored in the first processing liquid storage unit 3 to the first vapor generation unit 9 of the substrate processing unit 1. 45, a pump P1 for pumping the processing liquid in the first supply path 45, and a first supply path 45
And a first heater 46 disposed in the middle of the first heater. The first heater 46 is of a coiled tube type, and the processing liquid passing through the inside of the coiled pipe is adjusted to a predetermined temperature suitable for obtaining a predetermined evaporation amount of the processing liquid by hot water or cold water flowing outside the coiled pipe as required. Configuration. At the outlet of the first heater 46, a temperature sensor THP2 is arranged. The upstream end of the first supply path 45 is inserted below the liquid level of the first processing liquid storage unit 3 via the electromagnetic valve V1. Further, the downstream end of the first supply path 45 is connected to the processing liquid supply unit 18 in the first steam generation unit 9.

The base of a first return path 47 is connected to the return port 24 of the first steam generator 9. The end of the first recirculation path 47 is connected to the first supply path 45 via the solenoid valve V2. The second processing liquid supply unit 6 has substantially the same configuration as the first processing liquid supply unit 5, and includes a second supply path 5.
0, pump P2, second heater 51, temperature sensor THP4
And a solenoid valve V3. A second return path 52 for returning the processing liquid to the second processing liquid supply path 50 via a solenoid valve V4 is connected to the return port 44 of the second steam generation unit 2.

The gas supply unit 7 includes three minute flow control valves MFC1 to MFC3 connected collectively to a gas supply source (not shown) such as a nitrogen gas cylinder and five solenoid valves SV1 to SV.
5 is provided. Micro flow regulating valve MFC1 and MFC
Reference numeral 3 is for setting the mixing ratio between HF vapor and methyl alcohol vapor. The solenoid valve SV1 is arranged between the minute flow control valve MFC1 and the gas supply port 22, and is used to turn on and off the supply of nitrogen gas to the gas supply port 22. The solenoid valve SV2 is disposed between the steam outlet 23 and the steam inlet 26, and is connected to the steam outlet 23.
It is used to turn on and off the supply of steam from the to the steam inlet 26. The solenoid valve SV3 is a minute flow control valve MFC2.
, And is used for purging nitrogen gas in the inner housing 10. The solenoid valve SV4 includes a steam outlet 43 and a steam inlet 26.
And is used to turn on and off the supply of methyl alcohol vapor generated in the second vapor generation section 2. The solenoid valve SV5 is disposed between the minute flow rate regulating valve MFC3 and the gas supply port 42, and is used to pump generated steam under pressure.

This substrate processing apparatus includes a control unit 6 shown in FIG.
It has 0. The control unit 60 includes a microcomputer, a ROM, a RAM, and the like, and controls the sequence of the substrate processing apparatus. The control unit 60 includes solenoid valves V1 to V4 and SV
1 to SV5, pumps P1 and P2, micro flow regulating valve MFC
1 to MFC3 and driving units 61 to 72 and 81 to 84 for driving the motors M1, M2, M3, respectively. In addition, a keyboard 73, temperature sensors THP1 to THP4, liquid level detectors 93 and 94, a display unit 74, a transfer arm control unit 75 for controlling the transfer arm 34, and other input / output units are connected to the control unit 60. Have been.

Next, the operation of the substrate processing apparatus configured as described above will be described with reference to the control flowchart shown in FIG. When the program starts, initialization is performed in step S1. At the time of this initial setting, the temperature adjustment temperature, the flow rates of the pumps P1 and P2, the mixing ratio of HF vapor and methyl alcohol vapor, and the like are set to initial values.

In step S2, hot water is passed through the first heater 46 and the second heater 51 to start temperature control. When the temperature control is started, in the first processing liquid supply unit 5, the solenoid valve V1 is opened and the solenoid valve V2 is closed. And
The pump P1 is activated, and the processing liquid stored in the first processing liquid storage section 3 is supplied to the first steam generation section 9 via the first heater 46, and the processing liquid is supplied to the first steam generation section 9 in the first steam generation section. Container 15
From the second container 16. The liquid level detector 93 is
When it is detected that the processing liquid in the container 16 has reached a predetermined liquid level, the solenoid valve V2 is opened and the solenoid valve V1 is closed. Thereby, the processing liquid is supplied to the first supply path 45,
The first heater 46, the first steam generator 9, and the first processing liquid recirculation path 47 circulate.

Similarly, in the second processing liquid supply section 6,
At the start of temperature control, the solenoid valve V3 is opened and the solenoid valve V
4 is closed. Then, the pump P2 is started, and the processing liquid stored in the second processing liquid storage unit 4 is supplied to the second steam generation unit 2 via the second heater 51, and the processing liquid is
The water overflows from the third container 35 of the steam generator to the fourth container 36. When the liquid level detector 96 detects that the processing liquid in the fourth container 36 has reached a predetermined liquid level, the electromagnetic valve V4 is opened and the electromagnetic valve V3 is closed. Thus, the processing liquid circulates through the second supply path 50, the second heater 51, the second steam generator 2, and the second processing liquid recirculation path 52.

When the liquid level of the processing liquid in the second container 16 or the fourth container 36 decreases with the processing, the solenoid valve V1, V2 or V3, V4 is switched to set the processing liquid storage section. The processing liquid is additionally supplied from 3 or 4. In step S3, it is determined whether or not to change the setting of the mixing ratio of the HF vapor and the methyl alcohol vapor. This determination is made based on the input from the keyboard 73. When it is determined that the mixing ratio setting is to be changed, the process proceeds from step S3 to step S4. In step S4, the mixture ratio is set to the input ratio. In addition, HF that can be set
The mixing ratio of steam and methyl alcohol steam is 10: 1 to 1
It is within the range of 1:20.

If it is determined that the mixing ratio is not set, the flow shifts to step S5. In step S5, the process waits for a start instruction from the operator. When the operator inputs a start instruction, the process proceeds to step S6. In step S6, the process waits until the outlet temperature of the processing liquid (the temperature detected by the temperature sensors THP2 and THP4) is controlled to a constant temperature by temperature control.
When it is determined that the outlet temperature is controlled to a constant temperature, the process proceeds to step S7.

In step S7, a pre-spray is performed.
This is an operation for generating a steam by flowing a nitrogen gas through the steam generating units 2 and 9 on a trial basis before holding the substrate W. In step S8, the shutters 30, 31 are opened. Step S
In step 9, an instruction to carry in the substrate W is output to the transfer arm control unit 75. In step S10, a carry-in completion signal from the transfer arm control unit 75 is waited for. Upon receiving the carry-in completion signal, the flow shifts to step S11.

In step S11, the shutters 30, 31
Is closed, and the motor M1 is rotationally driven. This seals the inside of the inner housing 10 and rotates the sample stage 12. In step S12, the solenoid valves SV1, SV2, SV4,
Open 5. Then, nitrogen gas for pressure feeding is supplied into the first steam generation section 9 and the second steam generation section 2, and the generated steam is discharged from the steam discharge ports 23 and 43. HF discharged
The steam is supplied to the steam inlet 26 via the solenoid valve SV2. Also, the discharged methyl alcohol vapor is
It is supplied to the steam inlet 26 via the solenoid valve SV4.

Here, HF vapor and methyl alcohol vapor having a small surface tension are supplied simultaneously, and the supplied H
Since the F vapor and the methyl alcohol vapor are mixed and supplied onto the substrate W, the wettability of the substrate W is improved. In the step S13, waits for the lapse of the time T _1. The time T ₁ is the processing time. Here the processing time T ₁ is not necessary to include the pre-treatment time. That is, conventionally, a hydrophilic treatment is required to improve the wettability of the substrate W. However, in this embodiment, since the HF vapor and the methyl alcohol vapor are supplied at the same time, the wettability of the substrate W can be easily increased. And a hydrophilic treatment for improving wettability is not required. Because of this time T ₁ is shortened.

[0030] When the time T ₁ has elapsed the process proceeds to step S14. In step S14, the solenoid valves SV1, SV2, SV4,
Close 5. In step S15, the solenoid valve SV3 is opened.
As a result, the inner housing 10 is filled with nitrogen gas, and the vapor of the processing liquid is replaced with nitrogen gas. In the step S16 waits for the lapse of the time T _2. This time T ₂ is
This is enough time to finish purging with nitrogen gas.
The process proceeds to step S17 when the time T ₂ has elapsed.

In step S17, the solenoid valve SV3 is closed. Subsequently, in step S18, the shutters 30 and 31 are opened, and the motor M1 is turned off. In step S19, a discharge command is output to the transfer arm control unit 75. Step S2
If it is 0, it waits for a discharge completion signal from the transfer arm control unit 75. Upon receiving the discharge completion signal, the flow shifts to step S21.

In step S21, the transfer arm controller 7
It is determined from step 5 whether a processing end signal has been received. If the processing end signal has not been received, the process returns to step S9, and outputs a transfer command to the transfer arm control unit 75. If a processing end signal has been received, the process proceeds to step S22. In step S22, the shutters 30 and 31 are closed.
Then, the temperature control ends in step S23.

Here, since the first and second heaters 46 and 51 are arranged outside the first and second steam generators 9 and 2, the heat exchange area can be increased and the temperature can be controlled efficiently. it can. For this reason, regardless of whether the processing is performed or not, the first and the second
The temperature of the processing liquid at the outlets of the heaters 46 and 51 can be kept constant. The first and third containers 15, 35
Since the depth is shallow and the storage amount is small, the heat capacity of the processing liquid in the first container 15 or the third container 35 is small. Therefore,
By quantitatively supplying the processing liquid at a constant temperature, the heat balance between the amount of heat lost by vaporization and the amount of heat to be supplied can be easily maintained constant, and the temperature of the processing liquid can be constantly maintained during processing. .

Further, since the processing liquid is always overflowed,
Fluctuations in the liquid level of the processing liquid are eliminated, and fluctuations in the liquid temperature during processing are reduced, so that the amount of generated steam is substantially constant, and continuity and reproducibility of the processing can be improved. Further, since the mixing ratio of the two processing solutions can be set arbitrarily, an optimum mixing ratio can be obtained according to various processing contents.

[Other Embodiments] (a) In the above embodiment, the HF vapor and the methyl alcohol vapor were simultaneously supplied to improve the wettability on the surface of the substrate W. May be stored in a liquid mixture of HF and methyl alcohol. In this case, as shown in FIG.
May be provided to directly supply the steam generated in the space 21 to the steam space 25. The steam supply pipe 79 is automatically opened and closed by an on-off valve 80.

With such a configuration, the same effect as in the above embodiment can be obtained. (B) In the above embodiment, the processing liquid is directly circulated from the return paths 47 and 52 to the supply paths 45 and 50 during the processing of the substrate. However, as shown in FIG. , 52, the processing liquid may be returned to the processing liquid storage units 3, 4, and then supplied again from the processing liquid storage units 3, 4 to the supply paths 45, 50.

In such a configuration, the volume of the processing liquid to be temperature-controlled increases, but the solenoid valve V shown in FIG.
1 to V4 can be omitted. (C) Another hydrogen halide may be used instead of HF. Further, a solution having a small surface tension such as ethyl alcohol or isopropyl alcohol (IPA) may be used instead of methyl alcohol. (D) Instead of supplying the HF vapor and the methyl alcohol vapor at the same timing, the first time (for example, 20 seconds) at which the temperature of the methyl alcohol rapidly decreases from the start of the supply of the nitrogen gas (for example, 20 seconds). Only the methyl alcohol vapor may be introduced, and thereafter, when the methyl alcohol temperature is stabilized, the HF vapor and the methyl alcohol vapor may be mixed and introduced.

[0038]

In the steam generating apparatus according to the present invention, the temperature of the processing liquid is adjusted by the processing liquid temperature adjusting means while the substrate processing liquid is circulated, and the processing liquid is evaporated by the steam generating section. The temperature of the processing solution is stabilized regardless of the processing.
As a result, the reproducibility of the substrate processing is improved.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of a substrate processing apparatus employing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the substrate processing unit.

FIG. 3 is a sectional view of the steam generator.

FIG. 4 is a block diagram of the control system.

FIG. 5 is a control flowchart thereof.

FIG. 6 is a diagram corresponding to FIG. 1 of another embodiment.

FIG. 7 is a diagram corresponding to FIG. 1 of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate processing part 2, 9 Steam generation part 3, 4 Processing liquid storage part 45, 50 Supply path 46, 51 Heater 47, 52 Reflux path

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-348029 (JP, A) JP-A-3-20735 (JP, A) JP-A-63-14433 (JP, A) JP-A-3-3 80537 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/304

Claims (1)

(57) [Claims] A processing solution storage unit configured to store the substrate processing solution; a vapor generation unit configured to evaporate the substrate processing solution while overflowing the substrate processing solution to generate vapor of the substrate processing solution; A supply path for supplying the substrate processing liquid to the vapor generation section, a processing liquid temperature adjusting means provided in the middle of the supply path, and a processing liquid temperature adjustment for the substrate processing liquid overflowing in the vapor generation section in the supply path. A reflux path upstream of the means or a reflux path to a processing liquid storage section.