Fluid vapor mixing and delivery system

Abstract

An apparatus and method for delivering IPA vapor to a substrate processing chamber. In one aspect, the present invention comprises: a controller; a liquid mass flow controller (LMFC) associated with the vaporizer to convert the first liquid into a vapor; a mass flow controller (MFC) associated with the carrier gas; a mixing unit for mixing the vapor with a carrier gas to produce a predetermined mixture; and a discharge port line, the discharge port line comprising: a first flow path having a first valve between the mixing unit and the discharge port; a second flow path having a second valve between the mixing unit and the processing chamber; thereby, the first flow path may be opened until a predetermined mixture is achieved, and thereafter, the second flow path may be opened to allow the predetermined mixture to be delivered to the chamber.

Description

background field

[0001] Embodiments described herein relate generally to equipment used in the manufacture of electronic devices, and more particularly, to substrate processing systems that can be used to clean a surface of a substrate. Background Art

[0002] One of the most important tasks in the semiconductor industry is the cleaning and preparation of silicon surfaces for further processing. The main 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 the development of cleaning and contamination control technology, and in order to further reduce the size of IC components, the contamination level of silicon wafers must be further reduced. Wafer cleaning is the most frequently repeated operation in IC manufacturing and one of the most important parts of the semiconductor equipment business, and it looks like it will remain so for some time. Every time the device feature size is reduced or new tools and materials enter the manufacturing process, the cleaning task becomes more complex.

[0003] Most cleaning methods can be roughly divided into two major groups: wet and dry methods. 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 gas phase chemistry and rely on chemical reactions required for wafer cleaning, as well as other technologies such as laser, aerosol, and ozone chemistry.

[0004] 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 2 SO 4 / H 2 O 2 Solution, then immersed in dilute HF (hydrofluoric acid). Standard cleaning first operation (SC1) can be done with NH 4 OH / H 2 O 2 / H 2 O solution to remove particles, while the standard cleaning second operation (SC2) can use HCl / H 2 O 2 / H 2 O solution to remove metals. Despite increasingly stringent process requirements and orders of magnitude improvements in analytical techniques, chemical cleanliness, and DI water, the basic cleaning recipe has remained the same since this cleaning technology was first introduced. Since environmental concerns and cost-effectiveness were not major issues 30 years ago, RCA cleaning procedures were far from optimal in these respects.

[0005] Marangoni drying is a common method for drying wafers after processing in a wet bench. The 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 called the Marangoni effect. The Marangoni effect is characterized by: thin liquid films and bubbles, whereby stretching the interface results in a decrease in excess surfactant concentration at the surface, thereby increasing surface tension; the resulting surface tension gradient causes liquid to flow to the stretched area, providing a "healing" force and resistance to further thinning.

[0006] In the above Marangoni drying operation, IPA vapor is mixed with a carrier gas (such as N 2 ) and then delivered to the surface of the substrate via a nozzle. In most conventional designs, the IPA vapor produced 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 container to accommodate multiple chambers suitable for performing the Marangoni drying process. Due to the size of the cartridges, having a separate container for each cartridge is not an efficient use of space and also requires additional time as each container needs to be filled and refilled regularly.

[0007] Another challenge associated with surface drying using the foregoing methods relates to the ability to deliver a consistent concentration of IPA vapor in a carrier gas to the substrate surface through the IPA mixture dispensing component during the beginning, middle, and end of the Marangoni drying process. In one example, due to unstable flow experienced at the IPA mixture dispensing component during the initial stages of the Marangoni drying process, it may take several seconds before the desired concentration is reached at the beginning of the drying process. The result may result in drying-related defects or contamination of the substrate surface caused by incorrect flow rates and mixtures of IPA vapor and carrier gas provided to the substrate surface. In addition, in Marangoni-type dryers, it is desired that the throughput of substrates through the processing chamber remain constant, and delaying the Marangoni process to allow the IPA mixture to stabilize can create substrate throughput issues.

[0008] Therefore, there is a need for a more efficient fluid delivery system that requires less floor space while servicing multiple chambers.

[0009] There is a further need for a drying apparatus that permits constant substrate throughput while ensuring proper concentration of fluid throughout the drying cycle. Summary of the invention

[0010] The present disclosure generally describes an apparatus and method 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 fluid IPA into IPA vapor; a mass flow controller (MFC) associated with a carrier gas; a mixing unit for mixing IPA vapor with a carrier gas to produce a predetermined mixture; and an exhaust line including: a first flow path having a first valve between the mixing unit and the exhaust; a second flow path having a second valve between the mixing unit and the processing chamber; whereby the first flow path can be opened until a predetermined mixture is achieved, and thereafter, the second flow path can be opened to allow the predetermined mixture to be delivered to the chamber.

[0011] In another embodiment, a fluid box assembly includes: a controller; a first box, the first box having: an IPA container, the IPA container is used to contain liquid IPA, the liquid IPA is pressurized for delivery to a first liquid mass flow controller (LMFC) via a first fluid path, the first LMFC is associated with a first vaporizer to convert fluid IPA into IPA vapor; a first mass flow controller (MFC), the first MFC is associated with a carrier gas; a first mixing unit, the first mixing unit is used to mix IPA gas with a carrier gas to produce a predetermined mixture for delivery to a first processing chamber; a second box, the second box having: a second LMFC, the second LMFC is associated with a second vaporizer to convert fluid IPA into IPA vapor; a second MFC controller, the second MFC controller is associated with a carrier gas; a second mixing unit, the second mixing unit is used to mix IPA vapor with a carrier gas to produce a predetermined mixture for delivery to a second processing chamber; and a second fluid path, the second fluid path is between the IPA container and the second box. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to be able to understand the above-mentioned features of the present disclosure in detail, the present disclosure briefly summarized above may be described in more detail by reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only typical embodiments of the present disclosure and are therefore not to be considered as limiting the scope of the present disclosure, as the present disclosure may allow other equally effective embodiments.

[0013] Figure 1 is a cross-sectional view of a cleaning chamber in a CMP processing system according to one or more embodiments.

[0014] Figure 2 is a simplified diagram illustrating a gas delivery system according to one aspect of the present invention.

[0015] Figure 3 is a schematic diagram of components of a primary fluid cartridge according to one aspect of the present invention.

[0016] Figure 4 is a schematic diagram of one aspect of the present invention showing a primary fluid cartridge and a remote fluid cartridge. DETAILED DESCRIPTION

[0017] Figure 1 6 is a cross-sectional view of a cleaning chamber in a chemical mechanical polishing (CMP) processing system according to one or more embodiments. In general, an ICD chamber 110 can be used to remove contaminants from a substrate 200, which, if not removed, may cause the corresponding substrate 200 to fail to meet the cleanliness requirements of subsequent processing steps and be discarded. In one example, the ICD chamber 110 is configured to perform a cleaning and drying process that prevents water droplet marks from forming on the surface of the substrate 200. In the illustrated embodiment, the substrate is guided into the chamber 110 via an entrance door 610 on one side of the chamber, and after cleaning, the substrate leaves the exit door 615 on the opposite side. In general, the process performed in each ICD chamber 110 is the last cleaning process performed in the cleaning sequence performed on the 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 a rinse fluid (e.g., DI water) is supplied to the top side and / or the bottom side of the substrate, and then a drying process is performed on the substrate.

[0018] The ICD chamber 110 includes a substrate clamping device 603, a sweep arm 630, a first nozzle mechanism 640, a second nozzle mechanism 641, a gas chamber 680, a discharge port / 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 a state of a cleaning process or a retroreflective position sensing device for sensing a position of a substrate within the internal space 695.

[0019] 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, the second nozzle mechanism 641 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 the liquid IPA into vapor, and then mix the liquid IPA with a carrier gas (e.g., N ) provided from the carrier gas delivery source 645. 2 ) and then provided to the surface of the substrate during the Marangoni drying process.

[0020] During processing, once the substrate 200 is placed on the support of the substrate holding device 603, the support can be lowered to a position such as Figure 1 In one embodiment, as shown in Figure 1As shown in , the first nozzle mechanism 640 and the 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 one or more cleaning solutions used in the RCA cleaning process) to contact the substrate 200 at a first position 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 position. The edge-to-edge distance between the first nozzle mechanism 640 and the second nozzle mechanism 641 can be positioned so that the series of flows from the first nozzle mechanism 640 and the second nozzle mechanism 641 can be separated by a desired distance. As further described below, the IPA mixture can be generated before 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, when the first nozzle mechanism 640 and the second nozzle mechanism 641 are translated, a first fluid (e.g., DI water) may 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 may move the contact point of the fluids (the first position and the second position, respectively) from the center of the substrate to the edge of the substrate. The first nozzle mechanism 640 and the second nozzle mechanism 641 may be attached to each other to move in unison, or the first nozzle mechanism 640 and the second nozzle mechanism 641 may move independently.

[0021] 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 vapors) and / or airborne particles, etc., formed within the processing region of the ICD chamber 110 during processing. In some embodiments where nitrogen 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.

[0022] Figure 2 4 is a simplified diagram illustrating a fluid delivery system according to one aspect of the present invention. The system includes a housing 400 to house a vented main fluid cartridge 500 and two remote fluid cartridges 505, 510, wherein a fluid path 515 extends between the cartridges. As will be described in more 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 deliver a predetermined mixture to the processing chamber 110 (as described with reference to FIG. 4 ). Figure 1 The process chamber 110 shown and described previously mixes fluids, in this case IPA vapor and N 2 gas. Figure 2 It is intended to facilitate understanding of the placement of fluid cartridges 500, 505, 510 and the movement of liquid IPA within housing 400, and does not include the portion of the apparatus that actually mixes and delivers the gases to the chambers.

[0023] Figure 3 FIG. 5 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, which is typically heated using an inert gas (e.g., N 2 ) to pressurize the liquid IPA to push the liquid from the container along the flow line 521 to the liquid mass flow controller (LMFC) 525, which is used to automatically control the liquid flow rate according to the set flow rate command sent as an electrical signal from the system controller 530, regardless of the pressure condition of the liquid. The system controller 530 includes a programmable central processing unit (CPU) and communicates with multiple components of the fluid box 500, including the LMFC 525, the mass flow controller (MFC) 526, and the vaporizer unit 527 for converting the IPA fluid into IPA vapor. The dashed line 528 between the controller and other components illustrates the communication path and relationship between the components.

[0024] Liquid IPA is pushed from LMFC 525 through flow line 521 at a predetermined flow rate of liquid IPA to vaporizer unit 527, which is used to vaporize liquid IPA and deliver 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, which automatically controls N according to predetermined settings using system controller 530. 2 Then, the predetermined flow rates of IPA vapor and N 2 The gas enters the gas / vapor mixer 535. Once the IPA vapor is mixed with the nitrogen in the mixer, the predetermined mixture flows along the flow line 521 to the chamber 110.

[0025] Figure 3 Also shown is a drain line 700, which includes a "T" shaped junction 705, which has a first flow path 710 to the chamber 110 and a separate flow path 715 to the drain 720 (at Figure 1In each case, there are automatic control valves 730, 740 operable by the controller 530 to open and close the paths 715, 710 to the exhaust port 720 and the chamber 110, respectively. The exhaust port line 700 is constructed and arranged to ensure that the process gas (IPA vapor and N 2 The flow rate and concentration of the gas (i.e., the IPA vapor and N) are at or near a desired rate and / or predetermined mixture when directed into the chamber for delivery onto the surface of the substrate 200 via the nozzle 640. In one aspect of the present invention, the chamber valve 740 is initially closed and the exhaust valve 730 is opened, thereby admitting IPA vapor and N 2 The predetermined mixture of gases flows through flow path 715 to exhaust port 720. Once the flow has "ramp up" or reached a desired flow rate or steady state of flow, exhaust port valve 730 is closed and chamber valve 740 is opened to avoid subjecting nozzle 640 and substrate 200 to an inaccurate flow rate or mixture that could cause drying-related defects or contamination in the substrate when processing the substrate. In some cases, the inaccurate flow rate or mixture may include IPA vapor and N 2 The initial burst of the mixture of gases onto the surface of the substrate 200 has been found to generate particles and other related defects on the surface of the substrate. In one embodiment, once a preferred flow rate is established, the exhaust valve 720 is closed and the chamber valve 740 is opened simultaneously. In another embodiment, there is a delay between the closing of the exhaust valve 720 and the opening of the chamber valve 740. In yet another embodiment, the exhaust valve 720 is closed at a predetermined rate or to a certain point while the chamber valve 740 is opened in the opposite manner at the same rate. In another embodiment, when the substrate is passed through the entry door 610 ( Figure 1 ) is introduced into the chamber 110, the exhaust valve 730 is opened so that the mixture is at the correct flow rate when the substrate arrives at the substrate processing position, after which the exhaust valve is closed, the chamber valve 740 is opened, and the mixture with the better flow / mixture characteristics is provided to the nozzle 640. Once the substrate has been processed and moves toward the exit door 615, the chamber valve 740 is closed and the exhaust valve 720 is reopened. It should be understood that any number of timing arrangements regarding the open / closed positions of the valves 720, 740 are possible depending on various aspects of the particular process including the throughput requirements of the substrates in the chamber.

[0026] Figure 4 is a schematic diagram of an aspect of the present invention showing a primary fluid cartridge 500 and a remote fluid cartridge 510 . Figure 4 It 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 a housing having any number of fluid cartridges, each providing a predetermined fluid mixture to a designated chamber 110, 110a. Figure 4 Only one remote fluid cartridge 510 is included, but it will be appreciated 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 a 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 all IPA mixing components in the fluid cartridge. Figure 2 As shown in FIG, the remote fluid cartridge is physically smaller than the main fluid cartridge due to the absence of the IPA container, thereby saving valuable space and reducing the footprint of the housing 400. As shown, the remote cartridge 510 includes all of the components of the main fluid cartridge except for the liquid IPA container. The components of the remote fluid cartridge include N 2 Carrier gas source 540a, for N 2 MFC 526a for gas, LMFC 525a for liquid IPA, and IPA vaporizer 527a and mixing unit 535a. Also included are similar Figure 3 The vent line 700a of the vent line 700 is shown. A second fluid flow path 521a is provided from the IPA container 520 in the primary 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.

[0027] The exhaust line 700, 700a shown and described herein is particularly advantageous in processes that require nearly constant substrate throughput. In one example, a substrate is delivered to a chamber for processing and then immediately moved to a drying chamber. Any delay in ramping up a predetermined gas / vapor mixture may result in defects in the substrate. Once a predetermined vapor and carrier gas mixture is reached in the exhaust line, the predetermined vapor and carrier gas mixture can be maintained by keeping the exhaust valve open whenever the chamber valve is closed as the finished substrate is removed from the chamber by a robot and the next substrate is placed in the chamber.

[0028] 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, and the scope of the disclosure is determined by the claims that follow.

Claims

1. An apparatus for delivering a predetermined mixture of fluids to a substrate in a processing chamber, comprising: 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), the MFC being associated with the carrier gas; a mixing unit, the mixing unit being used to mix the vapor with the carrier gas to produce the predetermined mixture; A discharge outlet circuit, the discharge outlet circuit comprising: a first flow path having a first valve between the mixing unit and a discharge port; as well as a second flow path having a second valve between the mixing unit and the process chamber, Thus, the predetermined mixture is provided via the first flow path for at least a first period of time prior to opening the second valve in the second flow path to allow the predetermined mixture to be delivered to the surface of the substrate within the processing chamber.

2. The apparatus of claim 1, wherein the first liquid comprises isopropyl alcohol (IPA).

3. The apparatus of claim 2, wherein at the end of the first time period, while the second valve of the second flow path is opened, the first valve of the first flow path is closed.

4. The apparatus of claim 2, wherein at the end of the first time period, after opening the second valve of the second flow path, the first valve of the first flow path is closed.

5. The apparatus of claim 2, wherein at the end of the first time period, after the second valve of the second flow path is opened, the first valve of the first flow path remains open.

6. The apparatus of claim 2, wherein at the end of the first time period, 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 of claim 1, wherein the first flow path is configured to be opened at a predetermined time relative to a first position of the substrate in the processing chamber.

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

9. Apparatus as claimed in claim 8, whereby in the first position the substrate is directed into the chamber.

10. The apparatus of claim 8, whereby the second position is a processing position.

11. A fluid cartridge assembly, comprising: Controller; A first box, the first box having: 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 for converting the fluid IPA into IPA vapor; a first mass flow controller (MFC), the first MFC being associated with a carrier gas; as well as a first mixing unit for mixing the IPA gas with the carrier gas to produce the predetermined mixture for delivery to the first processing chamber; A second box, the second box having: a second LMFC associated with a second vaporizer to convert fluid 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; as well as A second fluid path is provided, the second fluid path being between the IPA container and the second cartridge.

12. The fluid cartridge assembly of 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 of claim 11, wherein the first cartridge and the second cartridge are housed in a housing.

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

15. The fluid cartridge assembly of 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: Controller; A first box, the first box having: 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 for converting the fluid IPA into IPA vapor; a first mass flow controller (MFC), the first MFC being 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 the first processing chamber; A second box, the second box having: a second LMFC associated with a second vaporizer to convert fluid 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; a second fluid path between the IPA container and the second LMFC of the second cartridge, wherein liquid IPA is pressurized for delivery from the IPA container to the second LMFC; A first exhaust port line, the first exhaust port line being associated with the first processing chamber, the first exhaust port line 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, whereby 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 exhaust port line, the second exhaust port line being associated with the second processing chamber, the second exhaust port line 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, whereby 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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