Thermally stable flow meter for precise fluid delivery

Abstract

The present disclosure relates to a fluid delivery device for a deposition chamber. The fluid delivery device includes a fluid flow meter. The fluid flow meter is enclosed in a thermally insulated box. An air inlet is provided on the thermally insulated box for providing a forced cooling air flow above the fluid flow meter. An exhaust port is provided on the thermally insulated box, and the forced cooling gas leaves the thermally insulated box from the exhaust port.

Description

Background Art Technical Field

[0002] The present disclosure relates generally to flow meters, and more particularly to thermally stable flow meters for precision fluid delivery.

[0003] Description of Related Technology

[0004] Semiconductor device manufacturing and the like involve various processes that generally require fluid to be delivered to a process chamber, such as an etching chamber or a deposition chamber, in precisely controlled amounts and / or flow rates. Generally speaking, the amount of fluid supplied in such a process is carefully controlled to provide the desired processing results, such as a specific film composition, film thickness, etching results, and the like. For example, in some processes, a silicon dioxide film is deposited on a substrate in a deposition chamber via a process utilizing a liquid tetraethyl orthosilicate (TEOS) solution as a precursor. In such a process, the liquid solution first flows through a liquid flow meter (LFM), then flows through a vaporizer, and then is supplied to the deposition chamber. In the deposition chamber, the precursor is decomposed in the presence of a radio frequency (RF) plasma, and is ultimately deposited on the substrate as a silicon dioxide film. In such a deposition scheme, any change in the amount and / or feed rate of the precursor fed into the deposition chamber may cause a change in the film deposition rate, and ultimately cause a change in the film thickness, film properties, and / or film composition of the final deposition.

[0005] Therefore, what is needed in the art is an improved liquid flow meter for accurate fluid delivery. Summary of the invention

[0006] In one embodiment, a fluid delivery device includes a fluid flow meter, and a thermal insulation box surrounding the fluid flow meter. An air inlet and an exhaust port are provided on the thermal insulation box. The air inlet provides a forced cooling air flow above the fluid flow meter, and the forced cooling gas leaves the thermal insulation box from the exhaust port.

[0007] In another embodiment, a modular fluid delivery device for incorporation in a precision gas panel includes: a first fluid flow meter, the first fluid flow meter being used to provide a first process fluid; and a second fluid flow meter, the second fluid flow meter being used to provide a second process fluid. A cold side plate is thermally coupled to the first flow meter and the second flow meter on a first side. A thermoelectric device is thermally coupled to the cold side plate on a second side opposite to the first side. A hot side plate is thermally coupled to the thermoelectric device. The thermoelectric device is between the cold side plate and the hot side plate. A heat exchange system is coupled to the hot side plate and is configured to remove heat from the modular fluid delivery device. An insulation box surrounds the first fluid flow meter and the second fluid flow meter. The present disclosure is not limited to modules having two fluid flow meters, and modules have different numbers of fluid flow meters, for example, three to six or more fluid flow meters may be utilized. Likewise, in other embodiments, a module may include only a single fluid flow meter.

[0008] In yet another embodiment, a fluid delivery device includes a plurality of fluid flow meters and a first box surrounding the plurality of fluid flow meters. An air inlet is provided on the first box, through which cooling gas enters the first box. An exhaust port is provided on the first box, through which heated cooling gas ("hot gas") leaves the first box. The exhaust port on the first box may include an exhaust mechanism to draw cooling gas from the first box. A second box surrounds the first box and provides a circulation path, through which cooling gas from the exhaust port returns to the air inlet. The cold side plate is thermally coupled to at least one side of the second box. The thermoelectric device is thermally coupled to the cold side plate. The hot side plate is thermally coupled to the thermoelectric device. The thermoelectric device is between the cold side plate and the hot side plate. A heat exchange system is thermally coupled to the hot side plate and is configured to discharge heat drawn from the plurality of fluid flow meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] It should be understood that the above general description and the following detailed description are only exemplary and are intended to provide an overview or framework for understanding the nature and characteristics of the claims. The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate (multiple) example embodiments and, together with the description, serve to explain the principles and operation of the various embodiments of the present disclosure.

[0010] In order to be able to understand in detail the manner in which the above-mentioned features of the present disclosure are achieved, a more particular description of the present disclosure briefly outlined above may be made with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only example embodiments and are therefore not to be considered as limiting the scope of the present disclosure, as the present disclosure may admit of other equally effective embodiments.

[0011] To facilitate understanding, identical reference numerals have been used, where possible, to designate substantially identical elements that are common to the different figures. It is contemplated that elements and features disclosed with respect to any one embodiment may be beneficially incorporated in other embodiments without specific recitation.

[0012] Additional features and advantages will be set forth in the following detailed description, and in part will be readily apparent to those skilled in the art from that description or may be recognized by practicing the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0013] Figure 1 A process chamber coupled to a gas panel for providing process fluids to the process chamber is schematically depicted according to one embodiment of the present disclosure.

[0014] Figure 2 Depicted is a cross-section of a fluid delivery device according to one embodiment of the present disclosure.

[0015] Figure 3 Depicted is a cross-section of a fluid delivery device according to one embodiment of the present disclosure.

[0016] Figure 4 Depicted is a cross-section of a fluid delivery device according to one embodiment of the present disclosure.

[0017] Figure 5 Depicted is a cross-section of a fluid delivery device according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0018] The present disclosure relates to a fluid delivery apparatus for a deposition chamber. The fluid delivery apparatus includes a fluid flow meter having improved thermal stability to improve the accuracy of fluid delivery. The fluid flow meter is enclosed in a thermally insulated box. An air inlet is provided on the thermally insulated box for providing a forced cooling air flow above the fluid flow meter. An exhaust port is provided on the thermally insulated box, and forced cooling gas leaves the thermally insulated box from the exhaust port.

[0019] Certain film deposition schemes used in semiconductor device manufacturing and other technical fields (such as flat panel display manufacturing) utilize liquid precursor materials fed into a vacuum deposition chamber. For example, as described above, the silicon dioxide film deposition process utilizes liquid TEOS as a precursor, which flows through a liquid flow meter (LFM) before being vaporized and fed into the deposition chamber. In such deposition schemes, it has been found that even small deviations in the precursor volume flow rate (such as about 1%) will result in significant film deposition rate changes. It has also been found that the LFM temperature has an unexpectedly significant effect on the accuracy of the liquid precursor flow measurement. For example, a change of about 20°C in the LFM body temperature may result in a precursor flow rate error of greater than 12%.

[0020] Generally speaking, the temperature of LFMs is not routinely controlled by separate means, except in cases where they are used to control ambient temperature within a manufacturing facility. As a result, flow measurements of these LFMs can be subject to significant errors when the temperature of the LFMs varies for any given reason. As a result, deposited films resulting from schemes that rely on LFMs are subject to significant variations in deposited film thickness and / or composition due to uncontrolled thermal variations of the LFMs or the local environment.

[0021] An LFM that controls the supply of liquid is a subset of a fluid flow meter (FFM) that controls the supply of fluid. The fluid may be a liquid phase material, a gas phase material, or a mixed phase material. Any description of an LFM is equally applicable to a description of an FFM.

[0022] Figure 1A process chamber 100 is schematically depicted according to one embodiment coupled to a gas panel 110 for providing various process fluids to the process chamber 100. The process chamber 100 is used to process a substrate 10, etc., and may be, for example, an atomic layer deposition chamber, an annealing chamber, a chemical vapor deposition chamber, a physical vapor deposition chamber, an etching chamber, a processing chamber, etc. The gas panel 110 is combined with one or more fluid flow meters (FFMs) 120. Each FFM 120 controls the supply of a process fluid (liquid or gas) to the process chamber according to a control signal provided by a controller 150. The process fluid is supplied from an external storage system (not shown) (such as a tank, a reservoir, or a generator) via an input supply line 130. After passing through the FFM 120, the process fluid is supplied to the process chamber 100 via an output supply line 140. Additional mechanisms (not shown) such as heaters, refrigerators, mixers, manifolds, vaporizers, condensers, filters, etc. may be disposed between and connected to the FFM 120 and the process chamber 100. Such additional mechanisms may be external to, in line with, or integrated with the output supply line 140. One or more FFMs 120 may be utilized to supply the same process fluid. It is also contemplated that each FFM 120 may be utilized to supply a different process fluid.

[0023] Typically, the gas panel 110 is connected to or equipped with an exhaust system 160. Among other purposes, the exhaust system 160 is intended to help maintain the FFM 120 at a specific operating temperature, such as approximately 25° C. However, the performance of the exhaust system 160 may be dependent on the facility-wide exhaust system 170, the performance of which may vary significantly during operation based on changes in exhaust loads that are generally not controllable, predictable, or easily compensated for at the facility.

[0024] In some examples, the exhaust system 160 may also draw cooling air from systems within the facility. This cooling air may vary in temperature and flow rate based on load changes that are also not easily controlled, predicted, or easily compensated for at the facility. The process fluid fed to the FFM 120 may also have a temperature that itself varies uncontrollably. Such fluctuations in process fluid temperature may cause temperature changes in the associated FFM 120. Likewise, temperature changes in one FFM 120 may cause temperature changes in adjacent or nearby FFMs.

[0025] Generally speaking, any temperature variation of the FFM 120 may cause variation in the amount of fluid supplied by the FFM 120 because the FFM 120 is typically calibrated for a specific operating temperature range (e.g., approximately 25° C.). Therefore, it would be desirable to provide a system with a more stable operating temperature to provide more accurate process fluid delivery via the FFM 120.

[0026] Figure 2 A fluid delivery device 200 according to the present disclosure is depicted. Generally, the fluid delivery device 200 is coupled to Figure 1 The fluid delivery device 200 provides a thermally stable operating environment for the FFM 120. The thermally stable operating environment for the FFM 120 improves the accuracy of fluid delivery via the FFM 120. Figure 2 As depicted, each FFM 120 is coupled or integrated with a fluid delivery device 200 via an optional mounting base 220 .

[0027] The fluid delivery device 200 includes at least one FFM 120 ( Figure 2 ), the at least one FFM120 is enclosed in a thermally insulated box 210 (such as a thermally insulating box). In general, the thermally insulated box 210 can be constructed of any thermally insulating material. For example, the thermally insulated box 210 can be constructed of a fabric coated with polytetrafluoroethylene ("PTFE"). The thermally insulated box 210 includes an air inlet 211 and an exhaust port 212. The air inlet 211 may optionally include a fan, an impeller, etc. to allow cooling gas (e.g., air at approximately 25°C) to flow into the thermally insulated box 210. The exhaust port 212 may optionally include a fan, an impeller, etc. to remove gas from the thermally insulated box 210, thereby facilitating acceptable flow of cooling gas within the thermally insulated box 210.

[0028] The positions of the air inlet 211 and the exhaust port 212 may vary depending on the desired internal flow rate of the cooling gas within the thermally insulated box 210. In one example, the air inlet 211 and the exhaust port 212 may be disposed on opposite sides of the thermally insulated box 210. In another example, the air inlet 211 and the exhaust port 212 may be positioned on adjacent sides of the thermally insulated box 210, or may be positioned on the same side of the thermally insulated box 210. Likewise, the flow rate of the forced cooling gas may vary depending on the thermal load and operating specifications of the FFM 120. For example, vibrations caused by the forced cooling airflow and / or any mechanism provided for driving the cooling airflow, etc. may adversely affect the performance of the FFM 120.

[0029] Additionally, it is possible to provide the air inlet 211 as multiple ports at varying positions on the thermally insulated box 210. For example, two or more air inlets 211 may be provided on one side of the thermally insulated box 210. In another example, two or more air inlets 211 may be provided on different sides of the thermally insulated box 210. Likewise, it is possible to provide the exhaust port 212 as multiple ports at varying positions on the thermally insulated box 210. Further, the number of ports provided for the air inlet 211 does not have to be equal to the number of ports provided for the exhaust port 212. For example, in one aspect of the present disclosure, the air inlet 211 may consist of one port, and the exhaust port 212 may consist of two or more ports.

[0030] Figure 3 A fluid delivery device 300 is depicted according to one embodiment. In the fluid delivery device 300, a thermoelectric cooler (TEC) 310, such as a Peltier device, is mounted to the FFM 120 via a cold side plate 320. In one embodiment, the cold side plate 320 is coupled to the optional mounting base 220 of the FFM 120. The TEC 310 is positioned between the cold side plate 320 and the hot side plate 330. A heat exchange system 340 is thermally coupled to the hot side plate 330. Figure 3 In the example depicted in FIG. 3 , the heat exchange system 340 includes a finned heat sink 341 coupled to an airflow manifold 342 to provide forced convection cooling over the finned heat sink 341, but generally any heat exchange method or combination of methods may be employed. For example, a simple heat sink plate, a finned heat sink, a forced convection system (gas or liquid system), and a combination of these methods may be utilized.

[0031] In general, the TEC 310 can be a single Peltier device or a plurality of such devices. The sizing of the TEC 310 can be determined based on the expected operating current and heat load. In addition, since the Peltier device can operate as a heater or a cooler depending on the voltage supplied to it, the temperature of the FFM 120 associated with the TEC 310 can be raised or lowered as needed to provide thermal stability. However, in typical operation, the TEC 310 is operated to extract heat from the associated FFM 120 and reject the heat to the hot side plate 330.

[0032] like Figure 3 As depicted, a single FFM 120 is enclosed within a thermally insulated box 350. In general, the fluid delivery apparatus 300 may be modular in design, permitting several fluid delivery apparatuses 300 to be incorporated into a gas panel 110.

[0033] Figure 4Depicted is a fluid delivery device 400 according to one embodiment. Generally speaking, fluid delivery device 400 is similar to fluid delivery device 300, except that cold side plate 320 is sized to permit at least two FFMs 120 (FFM 120a and FFM 120b) to be mounted in fluid delivery device 300, rather than a single FFM 120 being mounted in fluid delivery device 300. As depicted, two FFMs 120 are mounted on a single cold side plate 320 via two optional mounting bases (220a and 220b). Aside from the corresponding changes in sizing, the components in fluid delivery device 400 are otherwise substantially similar to the components in fluid delivery device 300, as indicated by the use of the same reference numerals for the components.

[0034] In addition, although Figure 4 120a, while the TEC 310 may be provided as a plurality of separate elements. For example, one TEC 310 cooling element may be disposed directly below the FFM 120a, while another TEC 310 cooling element may be disposed directly below the FFM 120b. The different elements comprising the TEC 310 may be controlled jointly or separately depending on the desired output characteristics of the fluid delivery device 400.

[0035] like Figure 4 As depicted, two FFMs 120 (120a and 120b) are enclosed within an insulated box 350. In general, the fluid delivery device 400 can be modular in design, thereby permitting several fluid delivery devices 400 to be incorporated into the gas panel 110. In general, there is no limit to the number of FFMs 120 that can be utilized within the insulated box 350, and additional FFMs 120 can be incorporated into the modular design scheme. For example, three, four, five, six or more FFMs 120 can be provided within the insulated box 350. Similarly, one or more TECs 310 can be utilized in various modular embodiments of the fluid delivery device 400. For example, three, four, five or more TECs 310 can be used with the fluid delivery device 400. In addition, the cold side plate 320 can be provided as a plurality of separate and modular units. For example, in a six FFM 120 embodiment, each pair of three pairs of FFMs 120 can be mounted on separate units of the cold side plate 320.

[0036] Figure 5Depicted is a fluid delivery device 500 according to one embodiment. In the fluid delivery device 500, at least one FFM 120 is disposed in a closed box 510. The closed box 510 has at least one air inlet 511, through which a cooling gas (e.g., clean dry air or high purity nitrogen) is supplied. The closed box 510 also includes at least one exhaust port 512, through which the cooling gas is drawn from the closed box 510 as a heated gas or hot gas. The air inlet 511 may be provided as a plurality of openings in the closed box 510 or a port on the closed box 510. The air inlet 511 may optionally include a fan, an impeller, etc., to supply forced cooling air through (a plurality of) openings or (a plurality of) ports. Similarly, the exhaust port 512 may be provided as a plurality of openings in the closed box 510 or a port on the closed box 510. The exhaust port 512 may optionally include a fan, impeller, etc. to push the heated cooling air ("hot air") out of the opening(s) or port(s). The specific placement of the air inlet(s) 511 and the exhaust port(s) 512 on the enclosure 510 is not limiting, and as Figure 5 The placement and arrangement of these aspects depicted are merely examples. Likewise, in some examples, one or both of the air inlet 511 or the exhaust 512 may optionally incorporate a gas moving mechanism (such as a fan or impeller) to facilitate circulation of cooling gas within the fluid delivery device 500.

[0037] The outer box 520 surrounds the closed box 510. The outer box 520 forms a substantially sealed area in which cooling gas is maintained. The outer box 520 provides a flow path for recirculating cooling gas exhausted from the closed box 510 (via the exhaust port 512) back to the intake port 511.

[0038] The outer box 520 is thermally coupled to the cold side plate 530 on at least one side. A thermal layer 540 is provided on the outer surface of the outer box 520 in a manner that does not limit the thermal coupling between the outer box 520 and the cold side plate 530. The thermal layer 540 can be a distinct thermal insulating material covering the outer box 520, or can be an integral part of the outer box 520. In one embodiment, the thermal insulating material is PTFE. Although Figure 5 The example depicted in shows a gap or separation between the thermal layer 540 and the outer box 520 , but the thermal layer 540 may be in direct contact with the outer box 520 in whole or in part.

[0039] like Figure 5As depicted, a plurality of TECs 310 are sandwiched between a cold side plate 530 and a hot side plate 550. The hot side plate 550 is thermally coupled to a heat exchange system 560. In general, the heat exchange system 560 can be substantially similar to the heat exchange system 340 described above in conjunction with the fluid delivery device 300. For example, a simple heat sink plate, a fin-type heat sink, a forced convection system (gas or liquid system), and combinations of these methods can be used with the heat exchange system 560.

[0040] In operation, heat from the FFM 120 is transferred to the cooling gas circulating within the closed box 510. The cooling gas extracts heat from the FFM 120 and is exhausted from the closed box 510 via the exhaust port 512 but is still maintained within the outer box 520. The exhausted cooling gas (now heated by the FFM 120) is then moved into thermal contact with the cold side plate 530, which has a temperature controlled by the TEC 310. The exhausted cooling gas (now cooled by the cold side plate 530) is then resupplied to the air inlet 511 of the closed box 510 via a recirculation path within the outer box 520. The heat transferred from the cooling gas to the cold side plate 530 is ultimately extracted to the outside of the fluid delivery device 500 via the operation of the heat exchange system 560.

[0041] like Figure 5 As depicted in the example of FIG, three TECs 310 are provided for six FFMs 120. In other examples, one TEC 310 may be provided for each FFM 120, or one TEC 310 may be provided for the entire fluid delivery device 500. In addition, when multiple TECs 310 are provided, each TEC may be controlled separately as needed to maintain thermal stability of the FFM 120.

[0042] Furthermore, while the specific examples provided above utilize thermoelectric coolers, other cooling systems are also contemplated, such as liquid chiller systems, evaporative coolers, and the like.

[0043] In this specification, "thermally coupled" refers to components through which heat can flow from one component to another without substantial obstruction. Thermally coupled components may be in direct physical contact, or a component such as thermal paste or other high thermal conductivity material may be interposed between the thermally coupled components.

[0044] Although the foregoing is directed to specific embodiments of the present disclosure, it should be understood that these embodiments are only illustrations of principles and applications. Therefore, it should be understood that various modifications may be made to the illustrative embodiments to provide other embodiments without departing from the spirit and scope of the present disclosure represented by the appended claims.

Claims

1. A fluid delivery device comprising: a fluid flow meter having a fluid inlet and a fluid outlet configured to route a process fluid through the fluid flow meter; a thermal insulation box, the thermal insulation box surrounding the fluid flow meter; an air inlet coupled to the thermal barrier, the air inlet configured to provide a forced cooling air flow around an exterior of the fluid flow meter; as well as an exhaust port, the exhaust port being coupled to the thermally insulated box, the forced cooling airflow exiting the thermally insulated box from the exhaust port; a cold side plate conductively coupled to the fluid flow meter and disposed between a cooler device and the fluid flow meter; as well as A hot side plate is conductively coupled to the cooler device and is disposed opposite the cold side plate and outside of the thermal barrier.

2. The fluid delivery device of claim 1, wherein: The fluid flow meter is configured to supply a process gas to a vacuum deposition chamber.

3. The fluid delivery device of claim 1, wherein: The air inlet includes a fan.

4. The fluid delivery device of claim 1, wherein: The exhaust port includes a fan.

5. The fluid delivery device of claim 1, further comprising: thermally coupled to the cold side plate of the fluid flow meter; said cooler device thermally coupled to said cold side plate; as well as The hot side plate is thermally coupled to the cooler device.

6. The fluid delivery device of claim 5, wherein: The cooler device is a thermoelectric cooler.

7. The fluid delivery device of claim 6, wherein: The thermoelectric cooler is a Peltier device.

8. The fluid delivery device of claim 1, wherein: The cold side plate is constructed from a number of individual and modular units.

9. A gas panel coupled to a process chamber, the gas panel comprising: At least one fluid delivery device as claimed in claim 1.

10. A fluid delivery device comprising: a fluid flow meter having a fluid inlet and a fluid outlet configured to route a process fluid through the fluid flow meter; a thermal insulation box, the thermal insulation box surrounding the fluid flow meter; an air inlet coupled to the thermal barrier, the air inlet configured to provide a forced cooling air flow around an exterior of the fluid flow meter; as well as an exhaust port, the exhaust port being coupled to the thermally insulated box, the forced cooling airflow exiting the thermally insulated box from the exhaust port; a cold side plate conductively coupled to the fluid flow meter and disposed between a cooler device and the fluid flow meter; a hot side plate conductively coupled to the cooler device and disposed opposite the cold side plate and outside the thermal barrier; as well as A heat exchange system is thermally coupled to the hot side plate.

11. The fluid delivery device of claim 10, wherein: The heat exchange system includes a fin-type heat sink coupled to the hot side plate and a forced convection system that pushes gas over the fin-type heat sink.

12. A modular fluid delivery device for incorporation into a precision gas panel, the modular fluid delivery device comprising: a first fluid flow meter, the first fluid flow meter being used to provide a first process fluid; a second fluid flow meter, the second fluid flow meter being used to provide a second process fluid; a cold side plate to which the first fluid flow meter and the second fluid flow meter are thermally coupled on a first side; a thermoelectric device thermally coupled to the cold side plate on a second side opposite the first side; a hot side plate, the hot side plate being thermally coupled to the thermoelectric device, the thermoelectric device being disposed between the cold side plate and the hot side plate; a heat exchange system coupled to the thermal side plate and configured to remove heat from the modular fluid delivery device; and A thermal insulation box surrounds the first fluid flow meter and the second fluid flow meter.

13. The modular fluid delivery device of claim 12, wherein: The thermoelectric device is a Peltier device.

14. The modular fluid delivery device of claim 12, wherein: The heat exchange system includes a forced convection system including at least one fan.

15. The modular fluid delivery device of claim 12, wherein: The heat exchange system includes a fin-type heat sink.

16. A fluid delivery device comprising: multiple fluid flow meters; a first tank enclosing a plurality of fluid flow meters; an air inlet, the air inlet being arranged on the first box, and cooling gas entering the first box through the air inlet; an exhaust port, the exhaust port being arranged on the first box, the cooling gas leaving the first box through the exhaust port; a second box surrounding the first box and providing a circulation path through which the cooling gas from the exhaust port returns to the intake port; a cold side plate thermally coupled to at least one side of the second tank; a thermoelectric device thermally coupled to the cold side plate; a hot side plate thermally coupled to the thermoelectric device, the thermoelectric device positioned between the cold side plate and the hot side plate; as well as A heat exchange system is thermally coupled to the hot side plate and configured to remove heat extracted from the plurality of fluid flow meters.

17. The fluid delivery device of claim 16, further comprising: A thermally insulating cover is on an outer side of the second box.

18. The fluid delivery device of claim 16, wherein: The thermoelectric device is a Peltier device and the cooling gas is high purity nitrogen.

19. The fluid delivery device of claim 16, wherein: The heat exchange system includes a fin-type heat sink thermally coupled to the thermal side plate and a forced convection system including at least one fan configured to force air over the fin-type heat sink.

20. A gas panel coupled to a process chamber, the gas panel comprising: At least one fluid delivery device as claimed in claim 16.

Images