Fluid vapor mixing and delivery system

Abstract

Apparatus and method for delivering IPA vapor to a substrate processing chamber. In one embodiment, the invention includes: a controller; a liquid mass flow controller (LMFC) associated with a vaporizer to convert a first liquid into vapor; a mass flow controller (MFC) associated with a carrier gas; a mixing unit that mixes the vapor with the carrier gas to produce the predetermined mixture; and a discharge circuit including: a first flow path having a first valve between the mixing unit and the discharge port; and a second flow path having a second valve between the mixing unit and the processing chamber; thereby, the first flow path can be opened until the predetermined mixture is achieved, and thereafter, the second flow path can be opened to allow the predetermined mixture to be delivered to the chamber.

Description

Fluid steam mixing and delivery system

[0014] Embodiments described herein relate generally to apparatus used in the manufacture of electronic devices, and more particularly, to substrate processing systems that can be used to clean the surface of a substrate. One of the most critical tasks in the semiconductor industry is cleaning and preparing silicon surfaces for further processing. The primary goals are to remove contaminants such as particles from the wafer surface and to control the chemical growth of oxides on the wafer surface. Modern integrated electronics would not be possible without advances in cleaning and contamination control technologies. To further reduce IC device dimensions, contamination levels on silicon wafers must be further reduced. Wafer cleaning is the most repetitive operation in IC manufacturing and one of the most critical components of the semiconductor equipment business, and it looks like it will remain so for some time. The cleaning task becomes more complex each time device feature sizes shrink or new tools and materials enter the manufacturing process. Most cleaning methods can be broadly divided into two categories: wet and dry. Liquid chemical cleaning processes are generally referred to as wet cleaning. They rely on a combination of solvents, acids, and water to spray, scrub, etch, and dissolve contaminants from the wafer surface. Dry cleaning processes use vapor-phase chemistry and rely on chemical reactions required for wafer cleaning, as well as other techniques such as lasers, aerosols, and ozone chemistry. For wet chemical cleaning methods, RCA cleaning, developed in 1965, still forms the basis for most front-end wet cleaning. A typical RCA type cleaning sequence begins with H 2SO 4 / H 2O 2 solution, then immersed in diluted HF (hydrofluoric acid). Standard cleaning first operation (SCI) can be done with NH 4OH / H 2O 2 / H 2O solution to remove particles, while the standard cleaning second operation (SC2) can use HCl / H 2O 2 / H 2O solution to remove metals. Despite increasingly stringent processing requirements and orders of magnitude improvements in analytical techniques, chemical cleanliness, and DI water, the basic cleaning recipe has remained unchanged since this cleaning technology was first introduced. Because environmental concerns and cost-effectiveness were not major concerns 30 years ago, RCA cleaning procedures were far from optimal in these respects. Marangoni drying is a common method for drying wafers after wet bench processing. This method uses the difference in surface tension gradients between IPA and DI water to help remove water from the wafer surface. This surface tension phenomenon is known as the Marangoni effect. The Marangoni effect is characterized by thin liquid films and foams stretching the interface, which reduces the excess surfactant concentration at the surface and increases surface tension. The resulting surface tension gradient causes the liquid to flow toward the stretched area, providing a "healing" force and resistance to further thinning. In the Marangoni drying operation described above, IPA vapor is mixed with a carrier gas (such as N 2) Mixed and then delivered to the substrate surface via a nozzle. In most conventional designs, IPA vapor generated in a refillable container is stored in a cartridge within the processing system. As substrate drying requirements increase, multiple fluid cartridges are required, each with its own reservoir, to accommodate multiple chambers suitable for performing the Marangoni drying process. Due to their size, equipping each cartridge with a separate reservoir is not only an inefficient use of space, but also requires additional time, as each reservoir needs to be regularly filled and refilled. Another challenge associated with surface drying using the aforementioned methods relates to the ability to deliver a consistent concentration of IPA vapor in the carrier gas to the substrate surface via the IPA mixture dispensing assembly during the start, middle, and end of the Marangoni drying process. In one example, due to unstable flow experienced at the IPA mixture dispensing assembly during the initial stages of the drying process, it can take several seconds before the desired concentration is reached at the start of the Marangoni drying process. This can result in drying-related defects or contamination of the substrate surface due to incorrect flow rates and mixtures of IPA vapor and carrier gas provided to the substrate surface. Furthermore, in Marangoni-type dryers, it is desirable to maintain a constant throughput of substrates through the processing chamber, and delaying the Marangoni process to allow the IPA mixture to stabilize can create substrate throughput issues. Therefore, there is a need for a more efficient fluid delivery system that requires a smaller footprint while servicing multiple chambers. There is a further need for a drying apparatus that permits constant substrate throughput while ensuring proper concentration of fluid throughout the drying cycle. The present disclosure generally describes apparatus and methods for delivering IPA vapor to a substrate processing chamber. In one aspect, the present invention includes: a controller; a liquid mass flow controller (LMFC) associated with a vaporizer to convert liquid IPA into IPA vapor; a mass flow controller (MFC) associated with a carrier gas; a mixing unit that mixes IPA vapor with the carrier gas to produce a predetermined mixture; and an exhaust circuit comprising: a first flow path having a first valve between the mixing unit and an exhaust; and a second flow path having a second valve between the mixing unit and the processing chamber. Thus, the first flow path can be opened until the predetermined mixture is achieved, and thereafter, the second flow path can be opened to allow the predetermined mixture to be delivered to the chamber. In another embodiment, a fluid cartridge assembly includes a controller; a first cartridge having an IPA container for containing liquid IPA pressurized for delivery via a first fluid path to a first liquid mass flow controller (LMFC), the first LMFC associated with a first vaporizer for converting the liquid IPA into IPA vapor; a first mass flow controller (MFC) associated with a carrier gas; a first mixing unit for mixing the IPA gas with the carrier gas to produce the predetermined mixture for delivery to a first processing chamber; a second cartridge having a second LMFC associated with a second vaporizer for converting the liquid IPA into IPA vapor; a second MFC controller associated with a carrier gas; a second mixing unit for mixing the IPA vapor with the carrier gas to produce the predetermined mixture for delivery to a second processing chamber; and a second fluid path between the IPA container and the second cartridge. FIG1 is a cross-sectional view of a cleaning chamber in a chemical mechanical polishing (CMP) processing system according to one or more embodiments. Generally, an ICD chamber 110 can be used to remove contaminants from a substrate 200 that, if not removed, could cause the corresponding substrate 200 to fail the cleanliness requirements of subsequent processing steps and be discarded. In one example, the ICD chamber 110 is configured to perform cleaning and drying processes to prevent the formation of water droplet marks on the surface of the substrate 200. In the illustrated embodiment, a substrate is introduced into the chamber 110 via an entry door 610 on one side of the chamber, and after cleaning, the substrate exits an exit door 615 on the opposite side. Generally speaking, the process performed in each ICD chamber 110 is the last cleaning process performed in a cleaning sequence performed on a substrate in the CMP system 100. The process performed in each ICD chamber 110 may include one or more cleaning steps in which a cleaning fluid or rinse fluid (e.g., DI water) is supplied to the top and / or bottom sides of the substrate, followed by a drying process performed on the substrate. The ICD chamber 110 includes a substrate clamping device 603, a scan arm 630, a first nozzle mechanism 640, a second nozzle mechanism 641, a gas chamber 680, a vent / exhaust port 660, and a gas source 670. The ICD chamber 110 may further include a sensing device 694, such as a camera for detecting the status of a cleaning process or a retroreflective position sensing device for sensing the position of a substrate within an interior space 695. One or more fluids may be applied to the processing side of the substrate 200 by the first nozzle mechanism 640 and the second nozzle mechanism 641. For example, the first fluid supply 643 may supply deionized water, an inert gas, and / or IPA vapor to the second nozzle mechanism 641, which is positioned to deliver the fluid to the surface of the substrate 200, and the first nozzle mechanism 640 may apply deionized (DI) water to the processing side of the substrate 200. As will be further disclosed herein, the IPA vapor is provided by an IPA vapor delivery assembly, which may include an IPA vapor generation source 644 and a carrier gas delivery source 645. The IPA vapor generation source 644 may include an IPA liquid vaporization device (not shown) configured to receive liquid IPA and convert it into vapor, which is then mixed with a carrier gas (e.g., N) provided from the carrier gas delivery source 645. 2) Mixed and then provided to the surface of the substrate during the Marangoni drying process. During processing, once the substrate 200 is placed on the support of the substrate holding device 603, the support can be lowered to a processing position as shown in FIG. 1 . In one embodiment, as shown in FIG. 1 , a first nozzle mechanism 640 and a second nozzle mechanism 641 can be positioned to each direct a flow of gas, vapor, or liquid onto the top surface of the substrate 200. The second nozzle mechanism 641 can flow one or more cleaning solutions, such as for an RCA cleaning process, to contact the substrate 200 at a first location above the substrate surface (e.g., the center of the substrate) during processing. The second nozzle mechanism 641 can also be used in a rinse cycle to flow an IPA mixture or some other surface tension reducing chemical onto the top surface of the substrate at a second location. The edge-to-edge distance between the first nozzle mechanism 640 and the second nozzle mechanism 641 can be positioned so that the cross-flows from the first nozzle mechanism 640 and the second nozzle mechanism 641 can be separated by a desired distance. As described further below, the IPA mixture can be generated prior to entering the processing chamber 100. The first nozzle mechanism 640 and the second nozzle mechanism 641 can be moved, for example, by pivoting or by linear translation across the substrate surface. During the drying process, as the first nozzle mechanism 640 and the second nozzle mechanism 641 translate, a first fluid (e.g., DI water) can be dispensed from the first nozzle mechanism 640 while an IPA mixture is provided from the second nozzle mechanism 641, thereby performing a Marangoni drying process. Moving the first nozzle mechanism 640 and the second nozzle mechanism 641 can shift the point of contact of the fluids (the first position and the second position, respectively) from the center of the substrate toward the edge of the substrate. The first nozzle mechanism 640 and the second nozzle mechanism 641 can be attached to each other for movement in unison, or the first nozzle mechanism 640 and the second nozzle mechanism 641 can move independently. The gas flow provided to the ICD chamber 110 can be provided at a desired pressure and flow rate to ensure removal of vapors (e.g., IPA vapor) and / or airborne particles, etc., that form within the processing region of the ICD chamber 110 during processing. In some embodiments where nitrogen gas is delivered to the ICD chamber 110, it may be desirable to eliminate the use of HEPA filters from the system to reduce system and maintenance costs and reduce system complexity. In some embodiments, the gas source 670 is configured to provide filtered air or other gas such that a desired pressure (e.g., greater than atmospheric pressure) is maintained within the processing region of the ICD chamber. FIG2 is a simplified diagram illustrating a fluid delivery system according to one aspect of the present invention. The system includes an enclosure 400 housing a vented main fluid cartridge 500 and two remote fluid cartridges 505, 510, with a fluid path 515 running between these cartridges. As will be described in greater detail herein, the fluid path 515 is used to transport liquid IPA from an IPA container (not shown) in the main fluid cartridge to the remote fluid cartridges. The fluid cartridges 500, 505, 510 are used to mix the fluids, in this case IPA vapor and N, before delivering a predetermined mixture to the processing chamber 110 (as shown and described with respect to FIG1 ). 2 Gases. FIG2 is intended to aid in understanding the placement of fluid cartridges 500, 505, 510 and the movement of liquid IPA within enclosure 400 and does not include the portion of the apparatus that actually mixes and delivers the gases to the chambers. FIG3 is a schematic diagram of components of a primary fluid cartridge 500 according to one aspect of the present invention. The components include a container 520 containing liquid IPA, typically using an inert gas (e.g., N 2) to pressurize the liquid IPA to push the liquid from the container along flow line 521 to a liquid mass flow controller (LMFC) 525 for automatically controlling the liquid flow rate. The liquid flow rate is controlled based on a set flow rate command sent as an electrical signal from a system controller 530, regardless of the pressure conditions of the liquid. The system controller 530 includes a programmable central processing unit (CPU) and communicates with various components of the fluid cartridge 500, including the LMFC 525, a mass flow controller (MFC) 526, and a vaporizer unit 527 for converting IPA fluid into IPA vapor. Dashed lines 528 between the controller and other components illustrate the communication paths and relationships between the components. Liquid IPA is pushed from LMFC 525 at its predetermined flow rate through flow line 521 to vaporizer unit 527, which vaporizes the liquid IPA and delivers the vaporized IPA to mixer 535. Separately, N is controlled by gas valve 545 (e.g., pressure regulator). 2 Gas source 540 enters its own MFC 526 and is automatically controlled by using the system controller 530 according to the pre-set settings. 2 gas flow rate. Then, the predetermined flow rate of IPA vapor and N 2 The gas enters the gas / vapor mixer 535. Once the IPA vapor and nitrogen are mixed in the mixer, the predetermined mixture flows along the flow line 521 to the chamber 110. Also shown in FIG3 is a vent circuit 700 comprising a T-junction 705 having a first flow path 710 to the chamber 110 and a separate flow path 715 to the vent 720 (also visible in FIG1 ). In each case, there are automatic control valves 730, 740 operable by the controller 530 to open and close the paths 715, 710 to the vent 720 and the chamber 110, respectively. The vent circuit 700 is constructed and arranged to ensure that the process gases (IPA vapor and N The flow rate and concentration of the IPA gas (IPA) are at or near the desired rate and / or predetermined mixture when introduced into the chamber for delivery to the surface of the substrate 200 through the nozzle 640. In one aspect of the present invention, the chamber valve 740 is initially closed and the exhaust valve 730 is open, allowing IPA vapor and N 2 gases flows through flow path 715 to exhaust port 720. Once the flow has "accelerated" or reached its desired flow rate or steady state, exhaust port valve 730 is closed and chamber valve 740 is opened, thereby avoiding subjecting nozzle 640 and substrate 200 to inaccurate flow rates or mixtures that could cause drying-related defects or contamination in the substrate while it is being processed. In some cases, the inaccurate flow rates or mixtures may include IPA vapor and N The initial burst of the mixture of gases onto the surface of substrate 200 has been found to generate particles and other related defects on the substrate surface. In one embodiment, once an optimal flow rate is established, exhaust valve 720 is closed and chamber valve 740 is simultaneously opened. In another embodiment, there is a delay between the closing of exhaust valve 720 and the opening of chamber valve 740. In yet another embodiment, exhaust valve 720 closes at a predetermined rate or to a certain point, while chamber valve 740 opens in the opposite manner at the same rate. In another embodiment, exhaust valve 730 is opened when a substrate is introduced into chamber 110 via entrance door 610 ( FIG. 1 ) to ensure the mixture is at the correct flow rate when the substrate reaches its processing position, after which the exhaust valve is closed and chamber valve 740 is opened to provide the mixture with optimal flow / mixture characteristics to nozzle 640. Once the substrate has been processed and is moving toward exit door 615, chamber valve 740 is closed and exhaust valve 720 is reopened. It will be appreciated that any number of timing arrangements are possible regarding the open / closed positions of the valves 720, 740, depending on the aspects of the particular process, including the throughput requirements of the substrates in the chamber. FIG4 is a schematic diagram of one aspect of the present invention, illustrating a main fluid cartridge 500 and a remote fluid cartridge 510. FIG4 is intended to illustrate the use of multiple fluid cartridges, all of which rely on a single liquid IPA container 520, in order to reduce the footprint of an enclosure having any number of fluid cartridges, each providing a predetermined fluid mixture to a designated chamber 110, 110a. While FIG4 includes only one remote cartridge 510, it should be understood that any number of remote fluid cartridges may be operated in accordance with aspects of the present invention, limited only by the number of associated chambers in a manufacturing facility and the capacity of the single IPA container 520 in the main fluid cartridge 500. In one aspect, the IPA container 520 is provided with a liquid level sensor (not shown), and the liquid IPA in the container is automatically maintained at a predetermined level sufficient to provide liquid to the IPA mixing components in all fluid cartridges. As shown in FIG2 , due to the lack of an IPA container, the remote fluid cartridges are physically smaller than the main fluid cartridge, thereby saving valuable space and reducing the footprint of the enclosure 400. As shown, the remote cartridge 510 includes all the components of the main fluid cartridge (except for the liquid IPA container). 2 Carrier gas source 540a, for N 3. The main fluid cartridge 500 includes an MFC 526a for IPA gas, an LMFC 525a for liquid IPA, an IPA vaporizer 527a, and a mixing unit 535a. A vent circuit 700a, similar to the vent circuit 700 described above with respect to FIG. 3, is also included. A secondary fluid flow path 521a is provided from the IPA container 520 in the main fluid cartridge 500 to the LMFC 525a in the remote fluid cartridge 510. In the illustrated embodiment, both cartridges 500, 510 rely on a single controller 530. The vent circuits 700, 700a shown and described herein are particularly advantageous in processes requiring a nearly constant substrate throughput. In one example, substrates are delivered to a chamber for processing and then immediately moved to a drying chamber. Any delay in accelerating the desired gas / vapor mixture can result in substrate defects. Once the desired vapor and carrier gas mixture is achieved in the vent circuit, it can be maintained by keeping the exhaust valve open whenever the chamber valve is closed, while the finished substrate is mechanically removed from the chamber and the next substrate is placed in the chamber. While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, the scope of which is to be determined by the following claims. 100: CMP system 110: ICD chamber 110a: Designated chamber 200: Substrate 400: Enclosure 500: Main fluid cartridge 505: Remote fluid cartridge 510: Remote fluid cartridge 515: Fluid path 520: Container 521: Flow line 521a: Secondary fluid flow path 525: LMFC 525a: LMFC 526: MFC 526a: MFC 527: Vaporizer unit 527a: IPA vaporizer 528: Dashed line 530: System controller 535: Mixer 535a: Mixing unit 545: Gas valve 603: Substrate clamping device 610: Inlet door 615: Outlet door 630: Sweep arm 640: First nozzle mechanism 641: Second nozzle mechanism 643: First fluid supply 644: IPA vapor generation source 645: Carrier gas delivery source 660: Discharge port / exhaust port 670: Gas source 680: Gas chamber 694: Sensing device 695: Internal space 700: Discharge port circuit 700a: Discharge port circuit 705: Connector 710: First flow path 715: Flow path 720: Discharge port 730: Automatic control valve 740: Automatic control valve In order that the above-described features of the present disclosure may be understood in detail, a more particular description of the disclosure, briefly summarized above, may be given by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments. FIG. 1 is a cross-sectional view of a cleaning chamber in a CMP processing system according to one or more embodiments. FIG. 2 is a simplified diagram illustrating a gas delivery system according to one aspect of the present invention. 3 is a schematic diagram of components of a primary fluid cartridge according to one aspect of the present invention. 4 is a schematic diagram of one aspect of the present invention showing a primary fluid cartridge and a distal fluid cartridge. Domestic deposit information (please note in the order of deposit organization, date, and number) None Foreign deposit information (please note in the order of deposit country, organization, date, and number) None 100:CMP system 110:ICD chamber 200:Substrate 603: substrate clamping device 610:Entrance door 615: Exit door 630: Sweep Arm 640: First nozzle mechanism 641: Second nozzle mechanism 643: First fluid supply 644: IPA vapor generation source 645:Carrier gas delivery source 660: Discharge port / exhaust port 670: Gas Source 680: Air Chamber 694:Sensing device 695: Interior Space 720: discharge port

Claims

1. An apparatus for conveying a predetermined mixture of fluids to a substrate in a processing chamber, comprising: One controller; A liquid mass flow controller (LMFC) associated with a vaporizer configured to convert a first liquid into a vapor; a mass flow controller (MFC) associated with a carrier gas; a mixing unit that mixes the vapor with the carrier gas to produce the predetermined mixture; and an outlet circuit including: a first flow path having a first valve between the mixing unit and the outlet. and a second flow path having a second valve between the mixing unit and the processing chamber; the predetermined mixture is provided via the first flow path for at least a first cycle time before the second valve in the second flow path is opened, via the discharge loop, to allow the predetermined mixture to be delivered to a surface of the substrate in the processing chamber.

2. The apparatus as claimed in claim 1, wherein the first liquid comprises isopropanol (IPA).

3. The device as claimed in claim 2, wherein at the end of the first cycle time, when the second valve of the second flow path is opened, the first valve of the first flow path is closed.

4. The device as claimed in claim 2, wherein at the end of the first cycle time, after opening the second valve of the second flow path, the first valve of the first flow path is closed.

5. The device as claimed in claim 2, wherein at the end of the first cycle time, after the second valve of the second flow path is opened, the first valve of the first flow path remains open.

6. The device as claimed in claim 2, wherein at the end of the first cycle time, the first valve of the first flow path is closed at a predetermined rate, and the second valve of the second flow path is opened at a substantially corresponding rate.

7. The apparatus as claimed in claim 1, wherein the first flow path is configured to open at a first position relative to the substrate in the processing chamber at a predetermined time.

8. The apparatus as claimed in claim 7, wherein the second flow path is configured to open at a second position relative to the substrate in the processing chamber at a predetermined time.

9. The apparatus as described in claim 8, wherein the substrate is introduced into the processing chamber in the first position.

10. The device as described in claim 8, wherein the second position is a processing position.

11. A fluid cartridge assembly, comprising: One controller; A first box comprising: an IPA container for containing liquid IPA, the liquid IPA being pressurized for delivery via a first fluid path to a first liquid mass flow controller (LMFC), the first LMFC being associated with a first vaporizer to convert the liquid IPA into IPA vapor; a first mass flow controller (MFC) associated with a carrier gas; a first mixing unit for mixing the IPA gas with the carrier gas to produce the predetermined mixture for delivery to a first processing chamber; a second box comprising: a second LMFC associated with a second vaporizer to convert the liquid IPA into IPA vapor; a second MFC controller associated with a carrier gas; a second mixing unit for mixing the IPA vapor with the carrier gas to produce the predetermined mixture for delivery to a second processing chamber; and a second fluid path between the IPA container and the second box.

12. The fluid cartridge assembly as claimed in claim 11, wherein the controller controls the first and second LMFCs, the first and second MFCs, and the first and second vaporizers.

13. The fluid cartridge assembly as claimed in claim 11, wherein the first and second cartridges are housed within a closed enclosure.

14. The fluid cartridge assembly as described in claim 11, further comprising: A third container, comprising: a third LMFC associated with a third vaporizer to convert fluid IPA into IPA vapor; a third MFC associated with a carrier gas; a third mixing unit that mixes the IPA vapor with the carrier gas to produce the predetermined mixture for delivery to a third processing chamber; and a third fluid path between the IPA container and the second container.

15. The fluid cartridge assembly as claimed in claim 14, wherein the second fluid path terminates at the second LMFC and the third fluid path terminates at the third LMFC.

16. A fluid cartridge assembly, comprising: One controller; A first container comprising: an IPA container for containing liquid IPA, the liquid IPA being pressurized for delivery via a first fluid path to a first liquid mass flow controller (LMFC), the first LMFC being associated with a first vaporizer to convert the liquid IPA into IPA vapor; a first mass flow controller (MFC) associated with a carrier gas; and a first mixing unit for mixing the IPA gas with the carrier gas to produce the predetermined mixture for delivery to a first processing chamber; and a second container comprising: a second LMFC associated with a second vaporizer to convert the liquid IPA into IPA vapor; a second MFC controller associated with a carrier gas; and a second mixing unit for mixing the IPA vapor with the carrier gas to produce the predetermined mixture for delivery to a second processing chamber; A second fluid path between the IPA container and the second LMFC in the second cartridge, wherein liquid IPA is pressurized to be delivered from the IPA container to the second LMFC; a first discharge loop associated with the first processing chamber, comprising: a first flow path having a first valve between the first mixing unit and a discharge port; a second flow path having a second valve between the first mixing unit and the first processing chamber, wherein the first flow path can be opened until the predetermined mixture is achieved, and thereafter the second flow path can be opened to allow the predetermined mixture to be delivered to the first chamber; and a second discharge loop associated with the second processing chamber, comprising: a first flow path having a first valve between the second mixing unit and a discharge port; A second flow path having a second valve between the second mixing unit and the second processing chamber, wherein the first flow path can be opened until the predetermined mixture is achieved, and thereafter the second flow path can be opened to allow the predetermined mixture to be delivered to the second chamber.

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