Double-pass flow plate for wet processing

Abstract

An apparatus for wet chemical processing includes a processing tank configured to hold a liquid chemical composition and support a plurality of substrates in the liquid chemical composition. A flow plate can be disposed in the processing tank beneath the plurality of substrates. The flow plate can include a plurality of liquid nozzles configured to direct liquid chemical composition into the tank and a plurality of gas outlets configured to direct gas into the tank.

Description

Technical Field

[0001] This disclosure relates to an apparatus for wet chemical processing. Background Technology

[0002] Wet processes, also known as wet chemical processes, are used in many stages of semiconductor device manufacturing. These wet chemical processes include etching, plating, cleaning, and other processes that place wafers or other substrates (e.g., immerse them) in chemical solutions. In some wet processing steps, such as electroless copper plating and etching, it is important to deliver gas to the bottom of the tank. Gas is released into the chemical solution in the processing tank through multiple orifices and forms bubbles that rise between wafers, panels, devices, etc. (generally referred to herein as “substrates”) positioned in the tank for processing. During processing (e.g., plating), byproducts of the chemical reaction form bubbles (e.g., hydrogen bubbles) on the substrate surface. These bubbles hinder the entry of chemical solutions into these areas and adversely affect film growth. Gas delivered to the bottom of the tank can form bubbles that help deliver oxygen (or other neutral gases) to the substrate surface, remove byproducts of the chemical reaction from the substrate surface, or generate pressure waves to inject fluid into cracks or vias on the substrate surface. Gases discharged into the liquid can also transfer momentum to the liquid flow between the substrates, thereby aiding in the transport of byproducts and precursors from the boundary layer on the substrate surface. Generally, gases discharged into the tank can be said to create randomness (similar to turbulence) in the chemical solution, thereby improving or promoting wet processing. For example, rising bubbles push the liquid in different directions as they move, thus generating pressure waves and pulsations in the liquid. These pulsations can disrupt the boundary layer on the substrate surface and generate additional liquid mixing in the vicinity of these surfaces. Therefore, the delivery of gas into the wet processing tank plays a crucial role in wet chemical processes. Traditionally, gas is injected into the wet processing tank using ejectors (or ejector tubes). However, ejector-type tanks may require space below the substrate basket to integrate a complex system of gas distribution pipes. Tanks that use laminar flow plates to guide the chemical solution into the tank may not have space to accommodate such gas distribution pipes. Positioning the ejector tube between the laminar flow plate and the substrate can adversely impede the free flow of the chemical solution into the space between the substrates. The apparatus and methods disclosed herein mitigate at least some of the aforementioned drawbacks. However, the scope of this disclosure is defined by the claims, and not by its ability to solve any problem. Summary of the Invention

[0003] Examples of apparatus and related methods for wet chemical processing of substrates are disclosed.

[0004] In one embodiment, an apparatus for wet chemical processing of multiple substrates is disclosed. The apparatus includes a processing tank configured to contain a liquid chemical composition and support the multiple substrates within the liquid chemical composition. A flow plate may be positioned within the liquid chemical composition in the processing tank such that the flow plate is positioned below the multiple substrates when they are supported in the liquid chemical composition. The flow plate may include a plurality of liquid nozzles configured to guide the liquid chemical composition toward the multiple substrates, and a plurality of gas outlets configured to guide gas toward the multiple substrates.

[0005] Various embodiments of the disclosed device may additionally or alternatively include one or more of the following features: the flow plate may be configured such that the flow rate of the gas directed into the tank and the flow rate of the liquid chemical composition directed into the tank can be independently varied; the plurality of liquid nozzles and the plurality of gas outlets may be uniformly spaced apart on the flow plate; the discharge opening of each of the plurality of liquid nozzles may have a diameter between approximately 0.05 inches and 0.1 inches; the discharge opening of each of the plurality of gas outlets may have a diameter between approximately 0.02 inches and 0.06 inches; the flow plate may be configured such that the flow rate of the gas through the plurality of gas outlets is less than approximately 50% of the flow rate of the liquid chemical composition through the plurality of liquid nozzles; the number of liquid nozzles in the plurality of liquid nozzles is the same as the number of gas outlets in the plurality of gas outlets.

[0006] Various embodiments of the disclosed device may additionally or alternatively include one or more of the following steps or features: the spacing between the plurality of liquid nozzles and the plurality of gas outlets may be 1 / N times the spacing between the plurality of substrates in the tank, where N is any value greater than or equal to 1; the spacing between the plurality of liquid nozzles is between approximately 0.05 and 1 inch in the length direction of the flow plate; the spacing between the plurality of liquid nozzles in the width direction of the flow plate may be the same as the spacing between the plurality of liquid nozzles in the length direction of the flow plate; the spacing between the plurality of gas outlets may be between approximately 0.05 and 1 inch in the length direction of the flow plate; the spacing between the plurality of gas outlets in the width direction of the flow plate may be the same as the spacing between the plurality of gas outlets in the length direction of the flow plate. The spacing in the angular direction can be the same; the plurality of liquid nozzles and the plurality of gas outlets can be arranged in an alternating linear array; the alternating linear array can extend in the length direction of the flow plate; the plurality of liquid nozzles and the plurality of gas outlets can be arranged to form a plurality of nested regions that can be independently controlled; each nested region of the plurality of nested regions may include one or more liquid nozzles and one or more gas outlets; each nested region of the plurality of nested regions may include only one of the liquid nozzles or gas outlets; the plurality of liquid nozzles and the plurality of gas outlets can be arranged on the top surface of the flow plate; the flow plate can form the bottom of the processing tank; the device can be an electroless copper plating device.

[0007] In another embodiment, a method for wet chemically treating multiple substrates is disclosed. The method includes positioning the multiple substrates in a processing tank containing a liquid chemical composition. The method further includes guiding the liquid chemical composition into the processing tank through multiple liquid nozzles of a flow plate positioned below the multiple substrates, and guiding gas into the processing tank through multiple gas outlets of the flow plate.

[0008] Various embodiments of the disclosed device may additionally or alternatively include one or more of the following steps or features: guiding the liquid chemical composition and guiding gas may include simultaneously guiding the liquid chemical composition and gas into the processing tank; positioning the plurality of substrates in the processing tank after simultaneously guiding the liquid chemical composition and gas into the processing tank; guiding the liquid chemical composition into the processing tank may include guiding a pulsating flow of the liquid chemical composition into the processing tank; guiding the gas into the processing tank includes guiding a pulsating flow of the gas into the processing tank. Attached Figure Description

[0009] The accompanying drawings, which are incorporated herein and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the specification, serve to explain the principles disclosed. In these drawings, reference numerals representing the same or similar structures, components, materials, and / or elements in different figures are similarly labeled where appropriate. It should be understood that various combinations of the structures, components, and / or elements, other than those specifically shown, are contemplated and are within the scope of this disclosure.

[0010] For simplicity and clarity, the accompanying drawings depict the general structure of various embodiments. Details of well-known components or features may be omitted to avoid obscuring other features, as these omitted features are well-known to those skilled in the art. Furthermore, features in the drawings are not necessarily drawn to scale. The dimensions of some features may be exaggerated relative to others to improve understanding of the exemplary embodiments. Those skilled in the art will understand that features in the drawings are not necessarily drawn to scale and, unless otherwise stated, should not be construed as representing dimensional or proportional relationships between different features in the drawings. Additionally, even if not explicitly mentioned, aspects described with reference to one embodiment or drawing may be applied to other embodiments or drawings and may be used in conjunction with other embodiments or drawings.

[0011] Figure 1 is a schematic diagram of an exemplary wet chemical treatment apparatus of this disclosure; Figures 2A-2C are schematic cross-sectional side views of exemplary integrated flow plates that can be used in the wet chemical processing apparatus of Figure 1; Figures 3A-3G are schematic top views of exemplary integrated flow plates that can be used in the wet chemical processing apparatus of Figure 1; Figure 4A is a cross-sectional side view of a portion of an exemplary integrated flow plate of this disclosure; Figure 4B is a perspective view of another exemplary flow plate of this disclosure; Figure 5 is a flowchart illustrating an exemplary method of using the device of Figure 1. Detailed Implementation

[0012] All related terms, such as “approximately,” “substantially,” “about,” etc., indicate that there may be a variation of ±10% (unless otherwise stated or specified). For example, a feature disclosed as approximately “t” units wide (or length, thickness, depth, etc.) may have a width that varies from (t-0.1t) to (t+0.1t) units. In some cases, the specification also provides context for some related terms used. For example, a structure described as substantially linear may deviate from linearity by ±10%. Furthermore, ranges described as varying between 5 and 10 (5-10) include the endpoints (i.e., 5 and 10).

[0013] Unless otherwise defined, all technical terms, symbols, and other scientific or technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Some components, structures, and / or processes described or referenced herein are well understood by those skilled in the art and are typically used using conventional methods. These components, structures, and processes will not be described in detail. All patents, applications, published applications, and other publications mentioned herein are incorporated herein by reference in their entirety. If any definition or description set forth in this disclosure is contrary to or inconsistent with the definitions and / or descriptions in these references, the definitions and / or descriptions set forth in this disclosure shall take precedence over those definitions and / or descriptions in the references incorporated herein by reference. No reference described or cited herein shall be considered prior art relative to this disclosure.

[0014] The following discussion describes exemplary apparatus and methods that can be used for wet chemical processing of substrates. Wet chemical processing is used for a variety of purposes in the manufacture of semiconductor and photonic devices, ranging from chemical removal of materials (wet etching) to material deposition (electroplating), to sample cleaning, and to creating patterns on surfaces using optical lithography techniques. As previously mentioned, the term "substrate" generally refers to components, such as wafers, panels, integrated circuit devices, printed circuit boards (PCBs), semiconductor packages, etc., that may undergo some type of wet chemical processing during manufacturing. While embodiments of this disclosure can be used with any wet processing apparatus, some aspects of this disclosure will be described in the following discussion with reference to a processing pool or tank for electroless copper plating. However, this is merely exemplary, and embodiments of this disclosure can be used with any wet chemical processing apparatus. Electroless copper plating is a chemical process in which a uniform layer of copper is deposited on the surface of a solid substrate, such as glass, metal, or plastic. This process may involve immersing one or more substrates in an aqueous solution containing copper salts and a reducing agent such as formaldehyde. Unlike electroplating, electroless plating processes typically do not require the passage of current through the pool and the substrate. The reduction of metal cations in solution is achieved through a purely chemical means, via an autocatalytic reaction.

[0015] Figure 1 is a schematic diagram of an exemplary wet plating apparatus 100 of this disclosure. In some embodiments, the apparatus 100 may be an electroless plating apparatus. A plurality of substrates 50 may be placed in a plating solution 30 in a plating tank 40 of the apparatus 10. Typically, at least the portion of the substrate 50 to be plated may be immersed in the plating solution 30. Typically, adjacent substrates of the plurality of substrates 50 may be spaced apart to allow the plating solution 30 to flow between the spaces and treat the exposed surfaces of the substrates 50. During operation, the plating solution in the tank 40 may be removed from the tank 40 through an outlet 32. In some embodiments, the removed plating solution may be treated (e.g., cleaned, filtered, etc.) and returned to the tank 40 through a flow plate 10 discussed below. In some applications, the liquid directed to the tank 40 may also be heated (or cooled) to a desired temperature. Although not shown in Figure 1, in addition to the plating tank 40, the apparatus 100 may also include other pools or tanks configured to perform different steps in the plating process, such as pre-plating treatment pools, collection pools, and rinsing pools. In some embodiments, multiple substrates 50 can be moved from one pool to another, for example, along a track. The composition of the plating solution 30 in the tank 40 depends on the application. In some embodiments of electroless copper plating, the plating solution can be an aqueous solution containing copper salts and a reducing agent such as formaldehyde. However, this is not required, and any plating solution now known or developed in the future can be used as plating solution 30.

[0016] The tank 40 may include an integrated flow plate 10 disposed in the plating solution 30. In some embodiments, as shown in FIG1, the flow plate 10 may be positioned below a plurality of substrates 50 in the tank 40. In some embodiments, the flow plate 10 may be positioned (e.g., coupled, attached, etc.) on the underside of the tank 40 such that the flow plate 10 forms the bottom of the tank 40. The flow plate 10 may be configured to simultaneously supply separate streams (e.g., unmixed) of plating solution 30 and gas into the plating tank 40. In some embodiments, the flow plate may be configured to direct plating solution and gas to the entire area of ​​the substrates 50 in the tank 40. In some embodiments, the flow plate 10 may be configured to direct plating solution and gas to the entire area of ​​the bottom of the tank. The flow plate 10 may include a plurality of liquid nozzles 12 (or outlets) configured to direct plating solution 30 into the tank 40 and a plurality of gas outlets 14 configured to direct separate gas streams into the tank 40. The liquid nozzles 12 and gas outlets 14 may have their discharge openings on the top surface of the flow plate 10 facing the plurality of substrates 50. In some embodiments, the liquid nozzle 12 and gas outlet 14 can be configured to direct the discharged liquid and gas toward a plurality of substrates 50 in the tank 40. Any type of gas (e.g., air, oxygen, nitrogen, inert gas, etc.) can be directed into the tank 40 through the gas outlet 14. In some embodiments, the liquid nozzle 12 and gas outlet 14 can be arranged in pairs such that the number of liquid nozzles 12 and gas outlets 14 is the same. In some embodiments, the liquid nozzles 12 and gas outlets 14 can be staggered orifices for simultaneously guiding separate flows of plating solution and gas from the underside of the tank.

[0017] Gas exiting gas outlet 14 and entering the liquid within tank 40 forms bubbles, which rise through the space between substrates 50 in tank 40. The flow around the rising bubbles and the flow in the space between substrates 50 can be laminar. However, the rising bubbles may push the liquid in different directions, generating pressure waves and pulsations, which may disturb the boundary layer (on the substrate surface) and create additional mixing of the liquid in the space between substrates 50. In an electroless process, these pressure waves can also help remove hydrogen bubbles formed on the substrate surface due to the electroless process. The bubbles can be of any size. In some embodiments, the bubbles can have a different size distribution (e.g., between 50-200 micrometers, 1-4 millimeters, etc.) and can increase in size as they rise to the surface.

[0018] Although the liquid guided into the tank 40 through the liquid nozzle 12 is described as a plating solution, generally any liquid can be guided into the tank through the nozzle 12. For example, when the tank 40 is used for etching, an etching solution may be allowed to enter the tank through the nozzle 12, and gases that aid the etching process may be guided through the gas outlet 14. The flow plate 10 may be configured to allow independent control of the gas and liquid flow rates entering the tank 40. In other words, the flow rates of the gas and liquid leaving the flow plate and entering the tank may be independently controllable or adjustable. In some embodiments, the flow plate 10 may be configured such that the flow rate of the gas entering the tank 40 (through the gas outlet 14) is less than approximately 50% (equivalent to standard liters per minute (SLPM)) of the flow rate of the liquid entering the tank 40 (through the liquid nozzle 12).

[0019] Generally, the liquid nozzle 12 and the gas outlet 14 (the opening) can have any size. In some embodiments, the liquid nozzle opening can have a size (e.g., diameter) between approximately 0.05 inches and 0.1 inches, and the gas outlet opening can have a size (e.g., diameter) between approximately 0.02 inches and 0.06 inches. In some embodiments, the gas outlet 14 can have a size (e.g., diameter) between approximately 0.02 inches and 0.08 inches. While not required, in some embodiments, each liquid nozzle 12 can have an opening of the same size, and each gas nozzle 14 can have an opening of the same size. In some embodiments, the discharge openings of the liquid nozzle 12 and the gas outlet 14 can be the same size. In some embodiments, the liquid nozzle 12 can be larger than the gas outlet 14.

[0020] In some embodiments, as schematically shown in FIG2A, the openings of the liquid nozzle 12 and gas outlet 14 of the flow plate 10 may be on the same plane. For example, the openings of the liquid nozzle 12 and gas outlet 14 may be located at the same height below the substrate, allowing liquid and gas to enter the tank at the same distance below the substrate. In some embodiments, as shown in FIG2B, the opening of the gas outlet 14 may be higher than the opening of the liquid nozzle 12, allowing liquid to enter the tank 40 below the gas. In some embodiments, as shown in FIG2C, the opening of the liquid nozzle 12 may be higher than the gas outlet 14, allowing gas to enter the tank 40 below the liquid. The liquid nozzle 12 and gas outlet 14 may be vertically spaced by any distance. In some embodiments, the liquid nozzle 12 and gas outlet 14 may be vertically spaced by approximately 0.1-0.5 inches. In some embodiments, the vertical position of the liquid nozzle 12 and / or gas outlet 14 on the flow plate 10 may be adjustable such that the vertical gap between the openings of the liquid nozzle 12 and gas outlet 14 can vary (e.g., between approximately 0.25 and 1 inch).

[0021] Generally, the liquid nozzle 12 and gas outlet 14 can be arranged on the flow plate 10 in any configuration. For example, in some embodiments, the gas outlet 14 can be arranged such that bubbles are concentrated on the side of the substrate where the desired processing occurs. For example, if the tank 40 is used for a copper electroless deposition process, such as depositing copper on one side of the substrate 50, the gas outlet 14 on the flow plate 10 can be arranged such that bubbles are concentrated on the side of the substrate 50 where copper deposition is required. In some embodiments, the gas outlet 14 can be arranged on the flow plate 10 such that bubbles rise through the space between the substrates 50 with minimal obstruction from the substrates 50.

[0022] Liquid nozzles 12 and gas outlets 14 can be arranged at any spacing on the flow plate 10. In some embodiments, the spacing between liquid nozzles 12 and the spacing between gas outlets 14 can be approximately (1 / N) times the spacing (or substrate spacing) of the substrates 50 in the slot 40, where N≥1. In some embodiments, the spacing of the openings (both liquid nozzles and gas outlets) in the flow plate 10 can be approximately (1 / N) times the substrate spacing. Generally, the substrate spacing can vary depending on the application. In some embodiments, the substrate spacing can be between approximately 10-25 mm (approximately 0.39-0.98 inches). Figures 3A-3F show plan views of a flow plate 10 with an exemplary layout of liquid nozzles 12 and gas outlets 14. In some embodiments, as shown in Figure 3A, the liquid nozzles 12 can have a spacing P between approximately 0.05-1 inch in at least one direction (e.g., along the length of the flow plate 10). L The gas outlet 14 can have a spacing P between approximately 0.05 and 1 inch. G In some embodiments, the spacing P of the liquid nozzles 12 L The distance P between the gas outlet 14 and the gas outlet 14 G The flow plate 10 can be the same in both its length and width directions. In some embodiments, the liquid nozzle 12 and the gas outlet 14 can be uniformly spaced and have a constant spacing in both the length and width directions of the flow plate 10. In other words, referring to FIG3A, P L and P G They can be roughly the same; the spacing between adjacent liquid nozzles 12 and gas outlets 14 can be approximately P. L / 2 (or P) G / 2). In some embodiments, as shown in FIG3B, the liquid nozzle 12 may have a constant spacing P in at least one direction. L And the gas nozzle 14 can have a constant spacing P G However, the gas outlet 14 can be positioned closer to the liquid nozzle 12. For example, P L and P GThey can be roughly the same, and the interval between adjacent liquid nozzles 12 and gas outlets 14 can be less than P. L / 2 (or P) G / 2). In some embodiments, the spacing P L and / or P G This can vary throughout the flow plate. For example, in some embodiments, the liquid nozzle 12 and / or gas outlet 14 may be closer to each other at the center of the flow plate 10 than at its edges. In some embodiments, the liquid nozzle 12 and / or gas outlet 14 may be closer to each other at the edges (or corners) of the flow plate 10 than at its center.

[0023] In some embodiments, as shown in FIG3C, the liquid nozzles 12 and gas outlets 14 can be arranged in an alternating linear array. In some embodiments, each linear array may extend in the same direction as the substrate 50 in the groove 40 (e.g., see FIG3D) or in the length direction of the groove 40. In some embodiments, the linear array may extend in the width direction of the groove 40. The liquid nozzles 12 and / or gas outlets 14 of each array can also be adjusted independently. For example, the flow rate of liquid exiting the liquid nozzle 12 (or gas exiting the gas outlet 14) through one array can vary independently of the other nozzles 12 (or openings 14). In some embodiments, as shown in FIG3D, the liquid nozzles 12 and gas outlets 14 can be arranged in an alternating linear array, and the liquid nozzles 12 and gas outlets 14 can be spaced apart such that pairs of liquid nozzles 12 and gas outlets 14 are positioned between adjacent substrates 50 in the groove 40. In some embodiments, similar to the embodiment of FIG3C, each array can be adjusted independently. In some embodiments, the flow rate of fluid exiting each adjacent pair of liquid nozzles 12 and gas openings 14 (labeled A and B in FIG. 3D) can vary independently of the other pairs.

[0024] In some embodiments, as shown in FIG3E, each gas outlet 14 may extend around a liquid nozzle 14 (or vice versa). In other words, the gas outlet 14 may be an annular opening around the liquid nozzle 12, such that the liquid discharged into the tank is surrounded by gas. In some embodiments, the liquid nozzle 12 may be an annular opening around the gas outlet 14, such that the liquid surrounds the gas. These concentric openings may have any of the above-described spacings.

[0025] In some embodiments, as shown in FIG3F, the openings (liquid nozzles and air outlets) in the flow plate 10 can be arranged in nested quadrilaterals or rectangles to form different regions that can be independently adjusted. In other words, the flow rate of the fluid (liquid or gas) entering the tank 40 through regions A, B, C, and D can be varied independently. In some embodiments, each region may include a mixture of liquid nozzles 12 and gas outlets 14. For example, regions A, B, C, and D may include both liquid nozzles 12 and gas outlets 14 arranged to form alternating openings or arranged in another pattern. In some embodiments, as shown in FIG3F, each region may include only one of liquid nozzles 12 or gas outlets 14. In other words, each region may include either liquid nozzles 12 or gas outlets 14. In some embodiments, certain regions (e.g., regions A and B) may include both liquid nozzles 12 and gas outlets 14, while other regions may include only liquid nozzles 12 or gas outlets 14.

[0026] Referring to FIG3G, in some embodiments, the size and / or spacing between the liquid nozzle 12 and the gas outlet 14 may cause the flow rate of liquid and / or gas in the region below the substrate 50 (or the basket carrying the substrate) (labeled P) to differ from that in the external regions (labeled Q, R, S, T). For example, in some embodiments, the size of the liquid nozzle 12 and / or gas outlet 14 in region P may be larger (or smaller) than the size of the liquid nozzle 12 and / or gas outlet 14 in other regions (e.g., regions Q, R, S, T). Alternatively or additionally, in some embodiments, the liquid nozzle 12 and gas outlet 14 may be spaced closer to each other (or further apart) in region P than in other regions. In some embodiments, the size and / or spacing between the liquid nozzle 12 and gas outlet 14 in regions Q, R, S, T may be the same as or different from that in region P. In some embodiments, the size and / or spacing between the liquid nozzle 12 and gas outlet 14 in some or all of regions Q, R, S, T may also be different. By using liquid nozzles 12 of different sizes (and / or different spacings) and gas outlets 14 in regions P, Q, R, S, and T, the flow rate of the fluid (liquid or gas) entering the tank 40 through these different regions can be varied independently. It is also conceivable that in some embodiments, the liquid nozzles 12 and gas outlets 14 may be provided only in region P.

[0027] The flow plate 10 may optionally include temperature control (e.g., one or more heaters 60) so that liquids and gases can be heated to a predetermined temperature before being directed into the tank 40. The dimensions of the flow plate 10 may depend on the application (e.g., the dimensions of the tank 40, the dimensions of the substrates 50, the number of substrates 50, etc.). In one exemplary embodiment, twelve (12) substrates spaced approximately 10 mm to 25 mm (approximately 0.39 to 0.98 inches) apart may be positioned in a tank having a length of approximately 27 inches, a width of approximately 15 inches, and a height of approximately 24 inches, each substrate having dimensions of approximately 510 mm × 515 mm (approximately 20.07 × 20.27 inches). In such an embodiment, the dimensions of the flow plate 20 may be substantially equal to (or slightly smaller than) the dimensions of the tank 70. In other words, the flow plate 10 may have a length of slightly less than 27 inches and a width of slightly less than 15 inches, so that the flow plate 10 can be tightly accommodated in the tank 70. In some embodiments, the flow plate 10 may form the bottom of the tank 40. The flow plate 10 may have any thickness. In some embodiments, the thickness of the flow plate 10 can be between approximately 0.5 and 4.0 inches. It should be noted that the rectangular flow plate is merely exemplary. Generally, the flow plate 10 can have any shape (see, for example, Figure 4B). In some embodiments, the shape of the flow plate 10 can depend on the shape of the tank in the wet processing equipment. The flow plate 10 can be made of any suitable material, such as polytetrafluoroethylene, perfluoroalkoxyalkylene (PFA), polypropylene, high-density polyethylene (HDPE), or another suitable metal, such as stainless steel, titanium, etc.

[0028] Separate liquid and gas flows can be guided through the flow plate 10 in any known manner. Figure 4A illustrates an exemplary flow plate 10 having separate liquid channels 12A and gas channels 14A for guiding separate liquid and gas flows through liquid nozzles 12 and gas outlets 14, respectively. In some embodiments, one or more heaters 60A, 60B may be positioned within the liquid and / or gas channels 12A, 14A to heat the fluid passing through those channels. In some embodiments, the liquid and / or gas channels 12A, 14A may include multiple separate conduits configured to guide liquid and / or gas at different flow rates through selected nozzles 12 and / or outlets 14. For example, the body of the flow plate may be integrally hollow or may include a labyrinthine channel with orifice-like outlets guided into a groove so that both liquid and gas jets can be discharged adjacent to each other into an upstream upflow. This can facilitate mixing and allow for different patterns of location, density, and distribution of gas and liquid orifices depending on the application. In some embodiments, the hollow flow plate may be replaced by a combination of a densely packed array of smaller diameter tubes for gas delivery (e.g., tube diameter less than half the distance between substrates) and an array of orifices inside the solid laminar flow plate, the orifice array having, for example, rectifier and baffle-like structures integrated with the upper surface of the laminar flow plate facing the substrate in the slot.

[0029] Figure 4B illustrates another embodiment of the flow plate 10', which can be used with some embodiments of some wet processing equipment. The flow plate 10' has a circular shape and includes a plurality of liquid nozzles 12 disposed on one of its surfaces. Liquid can be guided into a tank of the equipment through the liquid nozzles 12. In some embodiments of the flow plate, as shown in the flow plate 10' of Figure 4B, separate gas openings 14 can be eliminated. In some embodiments, the nozzles 12 can also guide gas into the tank. For example, the nozzles 12 can discharge liquid into the tank at a predetermined time and then discharge gas at a predetermined time (or vice versa). In some embodiments, gas openings (e.g., similar to those disclosed with reference to the foregoing embodiments) can be arranged alternately with the liquid openings 12 on the flow plate 10'. The size, spacing, and layout of the liquid nozzles 12 and the gas openings 14 can be similar to those disclosed above.

[0030] Figure 5 is a flowchart of an exemplary process 200 using the disclosed wet processing apparatus. One or more substrates may be placed in a tank of the wet processing apparatus containing a liquid chemical composition. (Step 210). As previously stated, the chemical composition contained in the tank depends on the application. In some embodiments, the one or more substrates may be at least partially immersed in the liquid in the tank. In some embodiments, multiple substrates may be spaced apart from each other and placed in the tank at a certain spacing (constant or variable spacing). The substrates may be spaced apart such that adjacent substrates are spaced apart from each other. A liquid flow (the same as the liquid in the tank) may then be directed into the tank through multiple openings or nozzles of a flow plate positioned below the substrates in the tank. (Step 220). Separate gas flows may also be directed into the tank through multiple gas openings arranged alternately with the liquid nozzles on the flow plate. (Step 230). In some embodiments, liquid and gas may be directed from the flow plate toward the substrates. For example, liquid nozzles and gas outlets may be positioned on the top surface of the flow plate facing the one or more substrates such that liquid and gas leaving the flow plate are directed toward the substrates. In some embodiments, liquid and gas can be simultaneously discharged into the processing tank. In some embodiments, the substrate can be placed in the tank after the liquid and gas have been guided into the tank through a flow plate. In other words, step 210 can be performed after steps 220 and 230 have begun. The flow rate of liquid and / or gas entering the tank through the flow plate can vary independently. In some embodiments, the flow rate of liquid and / or gas entering the tank through the flow plate can be constant or stable. In some embodiments, liquid can be guided into the tank in a pulsating manner through the flow plate (i.e., step 220). Additionally or alternatively, in some embodiments, gas can be guided into the tank in a pulsating manner through the flow plate. As used herein, pulsating or oscillating flow (as opposed to constant flow) refers to a fluid flow in which the flow rate varies periodically. The flow rate can oscillate in a rhythmic or random manner. Discharging gas along with liquid into the tank through a flow plate positioned below the substrate can disrupt the boundary layer located at the substrate surface and improve the processing of the substrate. Any wet chemical process (e.g., electroless plating, etching, cleaning, etc.) can be performed using process 200. The types of liquids and gases used in process 200 may depend on the application in which process 200 is used (e.g., electroless plating, etching, cleaning, etc.).

[0031] Wet chemical processes, such as electroless copper plating, are processes with limited mass transfer (or kinetic transport). At low deposition rates, copper at the interface between the plating bath and the substrate surface can be replenished through diffusion. However, when the deposition rate exceeds the diffusion rate, the deposition rate may decrease or even drop to zero. This reduced deposition rate is particularly problematic when plating narrow features with high aspect ratios, where plating bath replenishment is adversely affected by the geometry of the structure. Using the disclosed flow plate with integrated liquid and gas outlets enables the formation of uniform random or turbulent flow throughout the tank and allows for replenishment of the plating bath (or other liquids used) across all areas of the substrate surface, thereby improving the plating process.

[0032] Although this disclosure is described with reference to a wet processing apparatus for electroless plating, it is merely exemplary. Those skilled in the art will recognize that the disclosed apparatus can be used in any wet processing application. Furthermore, while some features are disclosed with reference to specific embodiments, those skilled in the art will recognize that this is merely exemplary and that these features are applicable to all disclosed embodiments. Other embodiments of the apparatus, its features and components, and related methods will be apparent to those skilled in the art upon consideration of the disclosure herein.

Claims

1. An apparatus for wet chemical processing of multiple substrates, comprising: A processing tank configured to contain a liquid chemical composition and support the plurality of substrates within the liquid chemical composition; as well as A flow plate, disposed within the liquid chemical composition in the processing tank, such that when the plurality of substrates are supported in the liquid chemical composition, the flow plate is positioned below the plurality of substrates, and wherein the flow plate comprises: Multiple liquid nozzles are configured to guide the liquid chemical composition toward the multiple substrates; as well as Multiple gas outlets are configured to direct gas toward the multiple substrates.

2. The apparatus of claim 1, wherein the flow plate is configured such that the flow rate of the gas directed into the tank and the flow rate of the liquid chemical composition directed into the tank can be varied independently.

3. The device according to claim 1, wherein the plurality of liquid nozzles and the plurality of gas outlets are uniformly spaced apart on the flow plate.

4. The device of claim 1, wherein the discharge opening of each of the plurality of liquid nozzles has a diameter between approximately 0.05 inches and 0.1 inches.

5. The device of claim 4, wherein the discharge opening of each of the plurality of gas outlets has a diameter between approximately 0.02 inches and 0.06 inches.

6. The apparatus of claim 1, wherein the flow plate is configured such that the flow rate of the gas through the plurality of gas outlets is less than about 50% of the flow rate of the liquid chemical composition through the plurality of liquid nozzles.

7. The device according to claim 7, wherein the number of liquid nozzles in the plurality of liquid nozzles is the same as the number of gas outlets in the plurality of gas outlets.

8. The device of claim 1, wherein the spacing between the plurality of liquid nozzles and the plurality of gas outlets is 1 / N times the spacing between the plurality of substrates, and wherein N is any value greater than or equal to 1.

9. The device of claim 1, wherein the spacing between the plurality of liquid nozzles is between approximately 0.05 and 1 inch along the length of the substrate.

10. The apparatus of claim 9, wherein the spacing between the plurality of liquid nozzles in the width direction of the flow plate is the same as the spacing between the plurality of liquid nozzles in the length direction of the flow plate.

11. The device of claim 9, wherein the spacing between the plurality of gas outlets is between approximately 0.05 and 1 inch along the length of the flow plate.

12. The apparatus of claim 11, wherein the spacing between the plurality of gas outlets in the width direction of the flow plate is the same as the spacing between the plurality of gas outlets in the length direction of the flow plate.

13. The device of claim 1, wherein the plurality of liquid nozzles and the plurality of gas outlets are arranged in an alternating linear array.

14. The device of claim 13, wherein each of the alternating linear arrays extends along the length of the flow plate.

15. The device of claim 1, wherein the plurality of liquid nozzles and the plurality of gas outlets are arranged to form a plurality of nested regions that can be independently controlled.

16. The device of claim 15, wherein each of the plurality of nested regions comprises one or more liquid nozzles and one or more gas outlets.

17. The device of claim 15, wherein each of the plurality of nested regions comprises only one of the liquid nozzles or gas outlets.

18. The device of claim 1, wherein the plurality of liquid nozzles and the plurality of gas outlets are arranged on the top surface of the flow plate.

19. The apparatus of claim 1, wherein the flow plate forms the bottom of the processing tank.

20. The apparatus of claim 1, wherein the apparatus is an electroless copper plating apparatus.

21. A method for wet chemically treating multiple substrates, comprising: Multiple substrates are positioned in a processing tank containing a liquid chemical composition; The liquid chemical composition is guided into the processing tank through multiple liquid nozzles on a flow plate positioned below the plurality of substrates; as well as Gas is guided into the processing tank through multiple gas outlets of the flow plate.

22. The method of claim 21, wherein guiding the liquid chemical composition and guiding gas comprises simultaneously guiding the liquid chemical composition and the gas into the processing tank.

23. The method of claim 22, wherein the plurality of substrates are positioned in the processing tank after the liquid chemical composition and the gas are simultaneously introduced into the processing tank.

24. The method of claim 21, wherein guiding the liquid chemical composition into the processing tank comprises guiding a pulsating flow of the liquid chemical composition into the processing tank.

25. The method of claim 21, wherein directing the gas into the processing tank comprises directing a pulsating flow of gas into the processing tank.

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