Substrate rinsing systems and methods

An example waterfall apparatus includes (1) a first portion of a first width having (a) a first plenum, a second plenum, and a restricted fluid path therebetween; (b) a first coupling surface; and (c) an inlet opening that creates a fluid path between the first coupling surface and the first plenum; and (2) a second portion of a second width larger than the first width and having (a) a second coupling surface; and (b) an inlet aligned with the first portion inlet opening. The first and second coupling surfaces form a slot that extends along at least a portion of a length of the waterfall apparatus and that connects to the second plenum. Fluid introduced into the second portion inlet fills the first plenum, travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall.

FIELD

The present application relates to semiconductor device manufacturing and is more particularly related to substrate rinsing systems and methods.

BACKGROUND

As semiconductor device geometries continue to decrease, the importance of ultra clean processing increases. Aqueous cleaning within a tank of fluid (or a bath) followed by a rinsing bath (e.g., within a separate tank, or by replacing the cleaning tank fluid) may achieve desirable cleaning levels. After removal from the rinsing bath, absent use of a drying apparatus, bath fluid may evaporate from the substrate's surface and cause streaking, spotting and/or leave bath residue on the surface of the substrate. Such streaking, spotting and residue can cause subsequent device failure. Accordingly, much attention has been directed to improved methods for drying a substrate as it is removed from an aqueous bath.

A method known as Marangoni drying creates a surface tension gradient to induce bath fluid to flow from the substrate in a manner that leaves the substrate virtually free of bath fluid, and thus may avoid streaking, spotting and residue marks. Specifically, during Marangoni drying a solvent miscible with the bath fluid (e.g., IPA vapor) is introduced to a fluid meniscus which forms as the substrate is lifted from the bath or as the bath fluid is drained past the substrate. The solvent vapor is absorbed along the surface of the fluid, with the concentration of the absorbed vapor being higher at the tip of the meniscus. The higher concentration of absorbed vapor causes surface tension to be lower at the tip of the meniscus than in the bulk of the bath fluid, causing bath fluid to flow from the drying meniscus toward the bulk bath fluid. Such a flow is known as a “Marangoni” flow, and can be employed to achieve substrate drying with reduced streaks, spotting or bath residue on the substrate.

Achieving uniform Marangoni drying of a substrate can be difficult and in some cases particles from the bath fluid may re-attach to and contaminate the substrate. As such, methods and apparatus for reducing particle re-attachment during rinsing and/or substrate drying are desired.

SUMMARY

In some embodiments, a waterfall apparatus configured to provide rinsing fluid to a substrate is provided that includes (1) a first portion of a first width having (a) a first plenum, a second plenum separated from the first plenum, and a restricted fluid path between the first and second plenums; (b) a first coupling surface; and (c) an inlet opening that creates a fluid path between the first coupling surface and the first plenum; and (2) a second portion of a second width that is larger than the first width and having (a) a second coupling surface; and (b) an inlet that aligns with the inlet opening of the first portion to create a fluid path to the first plenum through the second portion. The first coupling surface of the first portion and the second coupling surface of the second portion form a slot that extends along at least a portion of a length of the waterfall apparatus and that connects to the second plenum. Fluid introduced into the inlet of the second portion fills the first plenum of the first portion, travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall.

In some embodiments, a system configured to rinse a substrate is provided that includes a frontside waterfall apparatus, a backside waterfall apparatus, and a mounting mechanism that adjustably positions the frontside waterfall apparatus and the backside waterfall apparatus a predetermined distance apart so as to allow a substrate to pass between the frontside waterfall apparatus and the backside apparatus during a rinsing operation. Each of the frontside waterfall apparatus and the backside waterfall apparatus includes (1) a first portion of a first width having (a) a first plenum, a second plenum separated from the first plenum, and a restricted fluid path between the first and second plenums; (b) a first coupling surface; and (c) an inlet opening that creates a fluid path between the first coupling surface and the first plenum; and (2) a second portion of a second width that is larger than the first width and having (a) a second coupling surface; and (b) an inlet that aligns with the inlet opening of the first portion to create a fluid path to the first plenum through the second portion. The first coupling surface of the first portion and the second coupling surface of the second portion form a slot that extends along at least a portion of a length of the waterfall apparatus and that connects to the second plenum. Fluid introduced into the inlet of the second portion fills the first plenum of the first portion, travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall.

In some embodiments, a method of rinsing a substrate is provided that includes (1) providing a waterfall apparatus configured to provide rinsing fluid to a substrate comprising (a) a first portion of a first width having (i) a first plenum, a second plenum separated from the first plenum, and a restricted fluid path between the first and second plenums; (ii) a first coupling surface; and (iii) an inlet opening that creates a fluid path between the first coupling surface and the first plenum; and (b) a second portion of a second width that is larger than the first width and having (i) a second coupling surface; and (ii) an inlet that aligns with the inlet opening of the first portion to create a fluid path to the first plenum through the second portion; wherein the first coupling surface of the first portion and the second coupling surface of the second portion form a slot that extends along at least a portion of a length of the waterfall apparatus and that connects to the second plenum and wherein fluid introduced into the inlet of the second portion fills the first plenum of the first portion, travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall; (2) positioning a substrate in front of the slot of the waterfall apparatus; (3) directing a rinsing fluid into the inlet of the second portion to fill the first plenum of the first portion so that the rinsing fluid travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall; and (4) directing the rinsing fluid waterfall at the substrate to rinse the substrate. Numerous other aspects are provided.

DETAILED DESCRIPTION

As described previously, in some instances, particles from rinsing bath fluid used to rinse a substrate following a cleaning process may re-attach to and contaminate the substrate. For example, particles may re-attach to the substrate if the rinsing bath fluid used to rinse a substrate following cleaning has a different pH than the chemistry used during the prior cleaning step. In addition, contaminants may accumulate in the rinsing tank and may re-attach to a substrate as it is removed during drying. While such particle re-attachment may be reduced by adding chemicals to the rinsing fluid, adding chemistry to the final rinse tank may result in chemistry remaining on the substrate following drying.

In some embodiments provided herein, a highly uniform rinsing fluid curtain is employed to provide improved final rinsing of a substrate such as during Marangoni drying. For example, a “waterfall” plate may be provided above a final rinse tank to generate a highly-uniform rinsing fluid curtain that is blanketed by a flow of solvent (e.g., isopropyl alcohol (IPA) in a nitrogen carrier gas) to rinse and dry substrates after chemical mechanical planarization (CMP) and/or another cleaning process. While described as a waterfall, it will be understood that any suitable rinsing fluid may be used (e.g., de-ionized water, de-ionized water having a rinsing agent that reduces surface tension, gas-infused de-ionized water such as de-ionized water infused with O3, CO2, N2, etc.). In some embodiments, the waterfall is formed by forcing fluid flow through a narrow planar slot (e.g., formed between two plates).

In some embodiments, particle re-attachment may be avoided by submersion of a substrate into a rinsing fluid tank with chemistry such as an acid or base, HCl acid, HF acid, an organic alkaline, tetramethylammonium hydroxide (TMAH), ammonium hydroxide, another pH adjuster, or the like, and then lifting the substrate out of the tank through a waterfall, a top surface of which is blanketed with a flow of solvent such as an N2/IPA gas mixture. The resultant rinsing fluid curtain effectively rinses chemistry from the substrate, and the N2/IPA gas over the waterfall may provide Marangoni drying with reduced and/or minimized particle re-attachment.

FIG. 1Ais a perspective view of an example embodiment of a waterfall apparatus100aprovided herein in accordance with one or more embodiments of the invention. As shown inFIG. 1A, the waterfall apparatus100amay include a first (lower) portion102coupled to a second (upper) portion104. Any suitable coupling mechanism may be employed to couple the first and second portions102,104, such as screws, bolts, adhesives and/or the like. In some embodiments, the first (lower) portion102includes a main body106and a bottom plate108coupled to the main body106(e.g., a single-piece lower portion102or a multi-piece lower portion102may be employed). The second (upper) portion104includes an inlet110described further below.

The first portion102and/or second portion104may be fabricated from any suitable material such as aluminum, stainless steel, quartz, polyether ether ketone (PEEK), combinations of the same, or the like. Other materials may be employed.

FIG. 1Billustrates an alternative waterfall apparatus100bthat is similar to the waterfall apparatus100aofFIG. 1A. In the waterfall apparatus100bofFIG. 1B, the inlet110is located near an opposite end of the waterfall apparatus100bas shown.

FIG. 1Cillustrates a cross-sectional view of the waterfall apparatus100ataken along line1C-1C inFIG. 1A.FIG. 1Dillustrates a cross-sectional view of the waterfall apparatus110band inlet110taken along line1D-1D inFIG. 1B.FIG. 1Eillustrates an enlarged view of the cross-section ofFIG. 1C, andFIG. 1Fillustrates an enlarged view of an outlet portion of the waterfall apparatus100a.FIG. 1Gis similar toFIG. 1Fbut illustrates the use of a flow deflector (described further below) at an outlet of the waterfall apparatus100a.FIG. 1His a top view of the first (lower) portion102of the waterfall apparatus100awith the second (top) portion104removed.

With reference toFIG. 1CandFIG. 1E, the first portion102of the waterfall apparatus100aincludes a first plenum112separated from a second plenum114by a restricted fluid path116. When the first and second portions102,104are coupled together via a first coupling surface118of the first portion102and a second coupling surface120of the second portion104, a slot122is formed therebetween that extends from the second plenum114to an outlet124of the waterfall apparatus100a(or waterfall apparatus100b). As shown inFIG. 1D, the first portion102includes an inlet opening126that creates a fluid path between the first coupling surface118and the first plenum112through the first portion102. The inlet110aligns with the inlet opening126of the first portion102to create a fluid path to the first plenum112through the second (upper) portion104. As will be described further below, fluid introduced into the inlet110of the second portion104fills the first plenum112of the first portion102, travels through the restricted fluid path116to the second plenum114, and exits the slot122between the first and second portions102,104to form a rinsing fluid waterfall.

In the embodiments shown, the volume of the first plenum112is larger than the volume of the second plenum114. In some embodiments, the volume of the second plenum114may be the same or larger than the volume of the first plenum112.

In some embodiments provided herein, the first plenum112, the second plenum114and the restricted fluid path116(and/or slot122) have a similar length and extend nearly the entire length of the first portion102(as shown inFIG. 1H). For example, the first plenum112, the second plenum114, the restricted fluid path116and/or the slot122may be approximately the same overall length of the waterfall apparatus100aor110b, minus the material thickness employed to form the inlet region128and opposite side wall130of the first portion102as shown inFIG. 1H. Other and/or different lengths may be used for the first plenum112, the second plenum114, the restricted fluid path116and/or the slot122.

With reference toFIG. 1E, in some embodiments, a roof (upper side)132of the first plenum112may be angled relative to the first coupling surface118of the first portion102. Such an arrangement may reduce air trapping and/or bubble formation within the rinsing fluid and/or the first plenum112. For example, in some embodiments, the roof132may have the angle between about 1 and 10 degrees relative to the first coupling surface118(e.g., below horizontal inFIG. 1E). In other embodiments, the roof132may have an angle between about 3 and 6 degrees relative to the first coupling surface118. In yet other embodiments, the roof132may have an angle greater than about 3 degrees relative to the first coupling surface118. Larger or smaller roof angles may be employed.

Example volumes for the first plenum112range from about 120 to about 480 cm^3 for a 300 mm substrate. Example volumes for the second plenum114range from about 3 to about 12 cm^3 for a 300 mm substrate. Other plenum volumes may be employed. In some embodiments, the first plenum112may have a volume that is about 40 times the volume of the second plenum114. Other plenum volumes and/or plenum volume ratios may be used.

The restricted fluid path116creates a pressure increase in the rinsing fluid travelling from the first plenum112to the second plenum114. The rinsing fluid pressure then decreases as the rinsing fluid exits the restricted fluid path116and expands into the second plenum114. This may result in a highly uniform rinsing fluid pressure within the second plenum114, and thus a highly uniform rinsing fluid pressure within the slot122.

In some embodiments, the restricted fluid path116may have a width of less than about 2 mm, and in some embodiments between about 0.5 to 0.8 mm. Larger or smaller restricted fluid path widths may be employed.

The slot122is shown as being formed primarily in the first portion102. For example, a portion of the first coupling surface118of the first portion102may be machined away to form the slot122. In other embodiments, the slot122may be similarly formed in the second coupling surface120of the second portion. In yet other embodiments, the slot122may be formed by removing material from both first and second coupling surfaces118,120.

As shown inFIG. 1F, in some embodiments, the slot122may have a height h of less than about 0.5 mm, and in some embodiments, a height of about 0.2 mm or less. Larger or smaller slot heights may be employed. Example slot widths (e.g., the distance from the slot outlet124to the second plenum114) may be about 20 mm or larger in some embodiments, and about 30 mm or larger in some embodiments. Other slot widths may be employed.

With reference toFIGS. 1E-1F, in some embodiments, the first (lower) portion102has a smaller width than the second (upper) portion104. For example, the top of the slot122extends further at the outlet124than the bottom of the slot122(e.g., by a distance d inFIG. 1F). In some embodiments, the distance d may be about 5 mm or less, and in some embodiments, about 2 to 3 mm. Other distances may be used. In one or more embodiments, the ends of the first and second portions102,104at the outlet124of slot122are terminated with sharp edges as shown. For example, lower portion face134and/or upper portion face136may be angled relative to slot122to create sharp terminating edges. Example angles range from about 30 to 60 degrees relative to slot122, although other angles may be used. Use of sharp edges has been found to reduce rinsing fluid adhesion at the edge/fluid interface and may improve rinsing fluid flow rate, pressure and/or spray pattern uniformity at outlet124in some embodiments.

With reference toFIG. 1G, in some embodiments, a flow deflector138may be coupled to and/or formed as part of the second portion104to redirect a rinsing fluid stream140exiting the outlet124of slot122. For example, a flow deflector138may be attached to the second portion104to redirect the rinsing fluid stream140(e.g., downward) at a desired angle. In some embodiments, the rinsing fluid stream140may be redirected at an angle of about 40 to 60 degrees, and in some embodiments at an angle of about 45 to 50 degrees, below the path of the slot122, although other angles may be used. Redirecting rinsing fluid in this manner may facilitate adjustment of the angle with which rinsing fluid strikes a surface of a substrate as will be described further below with reference toFIGS. 4-5.

FIG. 2is a top view of waterfall apparatus100aand waterfall apparatus100bpositioned for rinsing a substrate200in accordance with one or more embodiments of the invention provided herein. As shown inFIG. 2, waterfall apparatus100ais positioned to spray rinsing fluid on a first side (e.g., a front or device side) of substrate200and waterfall apparatus100bis positioned to spray rinsing fluid on a second side (e.g., a back side) of substrate200as substrate200is moved between and past waterfall apparatus100aand waterfall apparatus100b. The waterfall apparatus100aand/or110bmay be positioned using a frame or similar structure202(shown in phantom). An example frame/structure for supporting waterfall apparatus100aand100bis described below with reference toFIG. 4and may be used to adjust one or more of the gap between the substrate200and each waterfall apparatus, the height of each waterfall apparatus and/or the angle of rotation of each waterfall apparatus.

In the embodiment ofFIG. 2, the slot122of each waterfall apparatus100a,100bis longer than a diameter of the substrate200rinsed by each waterfall apparatus100a,100b. This may compensate for bending of the outer edges of the waterfall output by each waterfall apparatus100a,100btoward the center of the waterfall due to capillary action at the outer edges (e.g., the rinsing fluid at the outer edges of the waterfall is pulled toward the rinsing fluid in the bulk or center region of the waterfall due to surface tension). For example,FIG. 3is a top view of the waterfall apparatus100boutputting a waterfall300directed toward substrate200. As depicted inFIG. 3, as the slot122outputs the waterfall300, the outer edges of the waterfall300are bent toward the center of the waterfall300as shown by bending angle302. The amount of bending at the edges of waterfall300depends on numerous factors such as surface tension and/or velocity of the rinsing fluid, the height of the slot122, the length of the slot122, flow rate of the rinsing fluid, horizontal distance from the slot122to the substrate, fluid density, or the like. It is also noted that the closer the substrate200is to the waterfall apparatus100b, the less effect the bending angle has on coverage of the substrate200.

To compensate for the above described bending angle, in some embodiments, the length of slot122of waterfall apparatus110aand/or110bmay be approximately 10 to 100 mm longer, and in some embodiments about 30 to 70 mm longer, than a diameter of the substrate200rinsed with the waterfall apparatus100aand/or100b. (In some embodiments, the first plenum112, second plenum114and/or restricted fluid path116may have the same or similar lengths.) For example, for a 300 mm substrate, in some embodiments, the slot122of waterfall apparatus100aand/or100bmay be approximately 310 to 400 mm in length, and in some embodiments about 330 to 370 mm in length. Larger or smaller slot lengths may be employed. In some embodiments, rinsing fluid surface tension, rinsing fluid velocity/flow rate, slot height, etc., may be adjusted to reduce bending angle. For example, a lower surface tension rinsing fluid and/or higher flow rate may be used, slot height may be decreased, a higher density rinsing fluid may be employed, etc.

FIG. 4is a side schematic illustration of an example system400for rinsing and/or drying a substrate in accordance with embodiments of the invention. With reference toFIG. 4, waterfall apparatus100aand100bare shown coupled to a mounting frame402. The mounting frame402allows adjustment of height, distance between and/or rotation of the waterfall apparatus100aand100b. For example, first slide mechanisms404aand404bsuch as adjustable clamps, slide bearings, adjustment screws or bolts or the like may be employed to adjust the height of and/or spacing between the waterfall apparatus100aand100b. Similarly, a pivot mechanism406, such as a slotted guide, may be employed to adjust rotation of each waterfall apparatus100aand100b. The mounting frame402may be formed from any suitable material such as aluminum, stainless steel, PEEK, a combination of the same, or the like.

In the embodiment ofFIG. 4, each waterfall apparatus100aand100bemploys a flow deflector138to direct rinsing fluid supplied by the waterfall apparatus100aand100btoward the substrate200at a desired angle. In some embodiments, the rinsing fluid may strike the substrate200an angle between about 40 and 60 degrees, and in some embodiments about 45-50 degrees, (relative to the major surface of the substrate200or from vertical inFIG. 4) during substrate rinsing. When flow deflectors138are employed, each waterfall apparatus100aand100bmay be oriented approximately horizontally as shown inFIG. 4(e.g., approximately perpendicular to the substrate200).FIG. 5illustrates an example embodiment in which waterfall apparatus100bdoes not employ a flow deflector138and is rotated so that rinsing fluid exiting the slot122strikes the substrate200at a predetermined angle.

With reference toFIG. 4, in some embodiments, the system400may include solvent vapor delivery mechanisms408aand408bfor delivering a solvent vapor to the rinsing fluid/substrate interface to affect Marangoni drying of the substrate200. During Marangoni drying with the system400, a solvent vapor (such as IPA) miscible with the rinsing fluid is introduced to each fluid meniscus which forms as the substrate200is lifted through the waterfalls provided by waterfall apparatus100aand100b. The solvent vapor is absorbed along the surface of the rinsing fluid, with the concentration of the absorbed vapor being higher at the tip of each meniscus. The higher concentration of absorbed vapor causes surface tension to be lower at the tip of each meniscus than in the bulk of the rinsing fluid, causing rinsing fluid to flow from each drying meniscus toward the rinsing fluid. Such a flow is known as a “Marangoni” flow, and can be employed to achieve substrate drying without leaving streaks, spotting or rinsing fluid residue on the substrate. It will be understood that the waterfall apparatus100aand/or100bmay be employed to rinse substrates whether or not substrate drying is performed.

In some embodiments, the system400may be employed to Marangoni dry a substrate removed from a tank or bath410containing a rinsing fluid412. In one or more embodiments, particle re-attachment during substrate rinse may be avoided by submersion of the substrate200into rinsing fluid412in the tank410and by adding a chemistry such as an acid or base, an organic alkaline, TMAH, ammonium hydroxide, another pH adjuster, or the like to the rinsing fluid412within the tank410. The substrate200then may be lifted out of the tank410through the waterfalls from waterfall apparatus100aand100bfor rinsing and/or Marangoni drying as described above. The resultant rinsing fluid curtain from each waterfall100a,100beffectively rinses chemistry from the substrate200, and the N2/IPA gas over each waterfall may provide Marangoni drying with reduced and/or minimized particle re-attachment.

FIG. 6is a flowchart of an example method600of rinsing and/or drying a substrate provided in accordance with embodiments of the invention. With reference toFIG. 6, in Block601the waterfall apparatus100aand/or100bis positioned so that rinsing fluid produced by the waterfall apparatus100aand/or100bstrikes a substrate at a desired angle. For example, each waterfall apparatus100aand100bmay be angled and/or flow deflectors138may be employed to direct rinsing fluid output by slot122at the substrate200at a desired angle (e.g., 40-60 degrees relative to the surface being rinsed in some embodiments).

In Block602rinsing fluid is provided to the inlet110of each waterfall apparatus100aand100b. Rinsing fluid travels through the inlet110to first plenum112, through restricted fluid path116to second plenum114and from second plenum114through slot122to form a rinsing fluid waterfall that strikes the substrate200. Example flow rates provided to the inlet110of each waterfall apparatus100aand100brange from about 4 to about 8 liters/minute, and in some embodiments about 5 to about 6 liters/minute. Other flow rates may be employed. Flow rate may depend on such factors as slot height, slot width, surface tension of the rinsing fluid, distance between the waterfall apparatus and the substrate, the angle at which the rinsing fluid strikes the substrate, etc.

In some embodiments, in Block603, a solvent vapor such as IPA may be directed at each waterfall/substrate interface to affect Marangoni drying of the substrate.

Each waterfall apparatus100aand100bmay provide a highly uniform-flow rinsing fluid curtain that can span a full substrate diameter. Each waterfall apparatus100aand100bmay provide a uniform slot exit velocity over a wide window of flow rates while reducing and/or minimizing cost, space, and pressure drop. In addition, through use of flow deflectors and/or angling the waterfall apparatus, adjustments may be made to the angle at which a flow stream strikes a substrate. Adjustments to the horizontal gap between the flow exit of the waterfall apparatus and the substrate surface may be made using the mounting frame402, for example.

The system400and/or waterfall apparatus100aand/or100bmay create a uniform rinsing fluid curtain (waterfall) through which a substrate may be moved, effectively rinsing both sides of the substrate. The addition of a solvent gas flow, such as nitrogen/IPA, above the rinsing fluid curtain enables effective drying of the substrate through the Marangoni process. Robust rinsing and drying of the substrate may be provided through uniform rinsing fluid flow across the length of the waterfall apparatus100aand/or100b(e.g., via slot122).

The angle that rinsing fluid exits the waterfall apparatus100aor100bmay affect meniscus shape of the rinsing fluid curtain when it contacts the substrate200. In some embodiments, a pure horizontal flow exiting the waterfall apparatus100aor100bthat strikes the substrate200approximately perpendicularly may produce a large and unstable meniscus. Angles between about 40 and 60 degrees relative to the surface of the substrate may create a more stable meniscus on the substrate and/or may be more conducive to Marangoni drying applications.

The angle at which rinsing fluid exits the waterfall apparatus100aor100bmay be controlled several ways. For example, flow deflector138may be attached to the waterfall apparatus100aor100b. Various angles may be machined into the flow deflector138. In some embodiments, the flow deflector138may be machined directly into the outlet124of the waterfall apparatus100aor100b.

As illustrated inFIG. 4, the waterfall apparatus100aand100bmay be attached to a mounting frame402that allows adjustment of the distance between the waterfall apparatus100a/100band the substrate200. In some embodiments, a (horizontal) gap between the waterfall apparatus100aand the waterfall apparatus100bmay be about 10 to 30 mm. Other gaps may be employed.

In some embodiments, the mounting frame402may allow adjustment of the position of the solvent vapor (e.g., N2/IPA) delivery mechanisms408a-brelative to the waterfall apparatus100aor100bto improve and/or optimize position and/or angle of impingement of solvent onto any meniscus formed by waterfall(s) rinsing the substrate. Example solvent vapor impingement angles and/or rates range from about 40 to about 80 degrees, and in some embodiments about 55 to 65 degrees (from horizontal for a vertically oriented substrate), and about 3 to 12 liters/minute, and in some embodiments from about 4.5 to 6 liters/minute. Other solvent vapor impingement angles and/or rates may be employed.

As stated, the waterfall apparatus100aand100bmay provide a highly uniform rinsing fluid flow across an entire surface of a substrate (e.g., flow rate variation of less than about 1% in some embodiments). A more uniform rinsing fluid flow may yield a more robust rinsing and drying process across the substrate. Additionally, air/bubble formation may be reduced within the waterfall apparatus100aand/or100b.

In general, the first and second plenums112,114may be triangular, circular or any other suitable shape. In some embodiments, the restricted fluid path116may include a series of openings rather than a single opening that extends the length of the slot122. In some embodiments, the slot122may be formed by using a saw-tooth or similarly shaped spacer that provides a series of openings across the length of the waterfall apparatus rather than a continuous opening. For example, in some embodiments, a saw-tooth-shaped spacer may be employed between the first and second coupling surfaces118and120to create a series of openings across the slot122(rather than a single opening).

While the waterfall apparatus100aand/or100bhas been described as using two plenums, it will be understood that additional plenums may be employed (e.g., 3, 4 or more plenums coupled by restricted fluid paths).

In some embodiments, the inlet to the waterfall apparatus100aand/or100bmay be positioned in other locations of the second portion104or on the first portion102(e.g., directly feeding the first plenum112, for example). In some embodiments, a waterfall apparatus configured to provide rinsing fluid to a substrate may include (1) a first portion having (a) a first plenum, a second plenum separated from the first plenum, and a restricted fluid path between the first and second plenums; (b) a first coupling surface; and (c) an inlet opening that creates a fluid path to the first plenum; and (2) a second portion having a second coupling surface. The first coupling surface of the first portion and the second coupling surface of the second portion form a slot that extends along at least a portion of a length of the waterfall apparatus and that connects to the second plenum. Fluid introduced into the inlet opening of the first portion fills the first plenum of the first portion, travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall. In some embodiments, a substrate may be positioned in front of the slot of the waterfall apparatus and rinsing fluid may be directed into the inlet opening of the first portion to fill the first plenum of the first portion so that the rinsing fluid travels through the restricted fluid path to the second plenum, and exits the slot between the first and second portions to form a rinsing fluid waterfall. The rinsing fluid waterfall may be directed at the substrate to rinse the substrate.