Point-of-use dynamic concentration delivery system with high flow and uniformity

Abstract

A method and system for mixing liquid chemicals in dynamically varying or static ratios with extremely high uniformity and repeatability during a given dispense is described. A mixer includes a plurality of fluid supply lines including elongated bladders defining linear flow paths and configured to expand laterally to collect process fluid and contract laterally to deliver a selected volume of process fluid to the mixer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 839,917, filed on April 29, 2019, entitled “POINT-OF-USE DYNAMIC CONCENTRATION DELIVERY SYSTEM WITH HIGH FLOW AND HIGH UNIFORMITY,” and U.S. Patent Application No. 16 / 560,481, filed on September 4, 2019, entitled “POINT-OF-USE DYNAMIC CONCENTRATION DELIVERY SYSTEM WITH HIGH FLOW AND HIGH UNIFORMITY,” the entire contents of which are incorporated herein by reference. background Technical Field

[0004] The present application relates to mixing and dispensing fluids, particularly for semiconductor microfabrication. More specifically, the present application relates to a method and system for providing a precise chemical supply to a mixer with extremely high uniformity and repeatability and also providing variable blending within the dispensed chemical.

[0005] Description of related technologies

[0006] Liquid chemicals are used in a number of semiconductor manufacturing processes, including but not limited to applying photoresists, developers, anti-reflective coatings, etching chemicals, solvents, and cleaning solutions. These chemicals are typically chemical mixtures with extremely precise ratios of reactive and non-reactive components. The ultra-small feature sizes of semiconductor devices drive high purity and mixing quality and uniformity requirements for these chemicals, as changes in concentration can negatively affect key feature parameters such as CD (critical dimension), LWR (line width roughness), and LER (line edge roughness). With feature sizes now below 10 nm, it is challenging to achieve high purity and high quality mixing. For example, conventional chemical suppliers typically spend a lot of time and effort using dedicated mixing equipment to provide large supplies of highly uniform liquid chemical solutions.

[0007] In semiconductor manufacturing, it may be highly desirable to mix or blend chemicals as they are dispensed on the wafer. Previous attempts have included viscosity control using an on-tool solvent and resist mixer that uses a conventional mixer and adjusts the valves between each dispense to achieve an acceptable setting based on thickness measurements. Another attempt used a viscometer to control the flow of photoresist and solvent into the mixer. While conventional attempts have provided some mixing benefits for static concentrations, they have failed to provide the mixing uniformity required in sub-10 nm microfabrication. Summary of the invention

[0008] The technology disclosed herein provides a system and method for mixing liquid chemicals in a dynamically changing, staged or static ratio with extremely high uniformity and repeatability during a given non-dispensing period. The uniformity and repeatability are high enough to support uniform distribution from a nozzle without dripping, dripping or interruption of the flow. Therefore, such devices and methods implement new distribution technologies for semiconductor manufacturing, including dynamically changing the concentration of the mixture during distribution. The features of the system described herein can reduce the resist distribution volume, reduce the number of distributions, and reduce the associated processing time. The ability to uniformly mix chemicals on a given tool at the point of use creates multiple process capabilities, improves process results and reduces processing time.

[0009] The hardware described herein can use individual chemical (resist, developer, rinse, metal or non-metal solution, organic or inorganic solution, etc.) concentrations and evenly mix solvents or other chemicals to produce different viscosities or other liquid properties. The hardware described herein can be used to provide variable mixing within a dispense to reduce the adverse effects of chemical changes that are too rapid, such as eliminating the negative effects of rapid pH changes during a TMAH / DI aqueous photoresist development process.

[0010] The hardware described herein enables the implementation of chemical mixtures and solutions that were previously not usable in production due to the fact that the solutions were unstable and reacted, decomposed, or precipitated out of solution in a very short time. By mixing the reactive components directly at the point of use, these chemicals can now be distributed in production without regard to the shelf life of the chemicals.

[0011] For the sake of clarity, the order of different steps as described herein is presented. Generally, these steps can be carried out in any suitable order. In addition, although each different feature, technology, configuration, etc. in this article may be discussed in different places of the present disclosure, it is intended that each concept can be performed independently of each other or in combination with each other. Therefore, the features of the application can be implemented and viewed in many different ways.

[0012] The Summary of the Invention section does not specify each embodiment and / or novel aspect of the present application. Instead, the Summary of the Invention only provides a preliminary discussion of different embodiments and novel corresponding points compared to conventional techniques. Additional details and / or possible viewpoints of the disclosed embodiments are described in the Detailed Description section of the disclosure as further discussed below and in the corresponding drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A more complete appreciation of the present invention and its many attendant advantages will be readily obtained as the invention becomes better understood by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0014] Figure 1A A schematic example of a microfluidic mixer is shown.

[0015] Figure 1B Another schematic example of a microfluidic mixer is shown.

[0016] Figure 1C Another schematic example of a microfluidic mixer is shown.

[0017] Figure 2 Shown is a perspective view of a capsule-based digital dispensing unit as described herein.

[0018] Figure 3 Shown is a perspective view of a nozzle assembly and a microfluidic mixer as described herein.

[0019] Figure 4A An embodiment of a microfluidic mixer is shown.

[0020] Figure 4B Shows Figure 4A Cross-section of the lower part of the microfluidic mixer.

[0021] Figure 5A An embodiment of a microfluidic mixer is shown.

[0022] Figure 5B Shows Figure 5A Another perspective view of the microfluidic mixer.

[0023] Figure 6 Schematic diagram showing a cross section of a tank of a microfluidic mixer.

[0024] Figure 7 A schematic diagram of the entire distribution system is shown.

[0025] Figure 8 A resist reduction mechanism as described herein is demonstrated.

[0026] Fig. 9A and Fig. 9BA pH shock elimination mechanism as described herein is demonstrated. DETAILED DESCRIPTION

[0027] References to "one embodiment" or "an embodiment" throughout this specification mean that the particular features, structures, materials, or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present application, but do not imply that they are present in every embodiment. Therefore, the phrases "in one embodiment" or "in an embodiment" that appear in various places throughout this specification do not necessarily refer to the same embodiment of the present application. In addition, in one or more embodiments, the particular features, structures, materials, or characteristics may be combined in any suitable manner.

[0028] The technology described herein combines the ability to precisely control liquid fluid supply using a digital dispensing unit previously disclosed in U.S. Patent 9,718,082 (“Inline Dispense Capacitor”) and U.S. Patent Application Publication Serial Nos. US 2018 / 0046082 (“High Purity Dispense Unit”), US 2018 / 0047562 (“High Purity Dispense System”), and US 2018 / 0047563 (“High Purity Dispense System With Meniscus Control”) with a novel mixer design that provides the precise mixing quality required for semiconductor processing and the desired dynamic response over the entire dispensing time range.

[0029] There are many ways to mix liquids. The various methods can be summarized into two main groups. The first group is to use chaotic turbulence to stir and mix the fluids together. The second group, which also plays an important role in the first group, is mixing by diffusion. Turbulent mixers essentially contain uncontrolled flows with constantly changing eddies and flow patterns. Although turbulence has the potential to quickly produce uniform mixing with steady-state flow inputs, their randomness involves the precise uniformity requirements of semiconductor chemicals and their output response to dynamically changing inputs. However, mixing by diffusion is defined by Fick's Law and varies with concentration gradient, distance and time. The concentration gradient is defined by the mixer input. For semiconductor applications, it is desired in this article to mix chemicals in the shortest possible time. This makes one variable (i.e., distance) the focus of the design in this article.

[0030] The technology in this paper combines microfluidic mixer ( Figures 1A to 1C), these microfluidic mixers mix chemicals in channels with widths and depths measured in millimeters. The small size of such channels eliminates any possibility of turbulent mixing. Therefore, the flows are completely mixed by diffusion in a completely laminar flow. The extremely short distance perpendicular to the flow for diffusion provides rapid mixing. The length of the channel and the flow rate of the fluid determine the mixing quality at the output of the channel in a predictable and repeatable manner. Changes in the input flow will result in predictable and repeatable changes in the output concentration after passing through the channel. These properties are desirable for semiconductor manufacturing. However, channel size can significantly limit flow rate. Embodiments herein scale channel size, such as by configuring the first mixer as a parallel channel array with dual inputs having a width and depth of micrometers ( Figure 1A and Figure 1B ) and the number necessary to support the desired flow rate. Considering that only the axis defining the thickness of the fluid layer ( Figure 1A and Figure 1B The Y axis in the figure) needs to be in the micrometer range, providing a depth of micrometers and a width (in Figure 1A and Figure 1B Scales a single flattened channel (increased on the Z axis in ).

[0031] Another embodiment incorporates micron channel sizes in a tank mixer, such as those described in U.S. Patent Application Publication No. US2016 / 0250606. This embodiment includes a scaled version of spiral mixing, where the input direction is similar to Figure 1C similar to that shown. The slot heights are scaled / extended so that they are relatively large compared to the slot width. By reducing the slot width that delivers the chemical to the central chamber where the flow is stratified and mixed, the mixing quality can be improved to the point where only a single mixing stage is required and the downstream volume from the mixing chamber to the nozzle can be significantly minimized. As the slot width is reduced, the flow cross section is also reduced, which in turn reduces the flow rate. Some embodiments address this issue by increasing the number of slots feeding the central chamber. Multiple feed slots help to quickly transition from one concentration to another while maintaining mixing quality. Another embodiment includes Figure 1C A parallel array of tank mixers of the type shown.

[0032] Embodiments herein may add a precise supply of chemicals to a mixer. Two or more supply lines to the mixer may be configured, and the mixer may include two or more inputs. The various chemicals may be supplied by precision pumps or valves. In the case of pumps, various embodiments of the elongated bladder system may be used. Examples are in Figure 2 Shown in.

[0033] In one embodiment, the mixer includes a first fluid supply line including an elongated capsule defining a linear fluid flow path and configured to expand laterally and collect a charge of a first process fluid, and contract laterally to deliver a selected volume of the first process fluid to the mixer. The system may include a control valve between the elongated capsule unit and the mixer input. This configuration allows the valve to be closed and allows the elongated capsule to be refilled. This valve may optionally include a backflow feature or mechanism. A constant pressure supply may be provided by a pressurized chemical supply container. The elongated capsule is digitally controlled and provides precision control of the supply of chemicals to the mixer. Precision control of the chemical composition of the mixer output is implemented by precision control of the mixer input. A filter located upstream of the elongated capsule unit may be included to increase the purity of the chemical. The valve may be positioned upstream of the elongated capsule unit and optionally before the filter (if present). This valve may be used to prevent backflow when the capsule unit is dispensed through the mixer and the nozzle.

[0034] Alternatively, the capsule unit supplying liquid chemicals can function without a control valve between the capsule unit and the mixer input. A nozzle with a meniscus control can be included to maintain the meniscus in a desired position during refilling of the capsule unit or between distributions. In the case of two or more supply lines to the mixer and nozzle, each supply line can be refilled in a continuous sequence. Backflow at the nozzle can be implemented by one or more capsule units. A filter located upstream of the capsule unit can improve the purity of the chemical. When the capsule unit is distributed through the mixer and nozzle, an optional valve located upstream of the capsule unit and before the filter (if included) can be used to prevent backflow.

[0035] Other embodiments may use pneumatic or electrically driven adjustable valves to control the total input flow of chemicals into the mixer, such as in place of a bladder unit. These valves may include speed control and / or adjustable stops to limit the maximum flow through the valve. The valves are sequenced to enable phase changes from chemical A to chemical B and vice versa between given allocations. Speed ​​control enables chemical blending during allocation. Backdraft control may or may not be included as a valve function. A constant or variable pressure supply should be available behind the valve to push the fluid through.

[0036] The mixer herein can be closely coupled to or integrated with the dispensing nozzle itself. Wire electronic discharge machining (wire EDM) can be used to produce grooves down to about 150 μm, or other techniques such as etching or additive manufacturing can be used. For some semiconductor dispensing applications, a groove width of 150 μm may be too large to meet the mixing uniformity goals of a single stage. For these applications, two mixers can be placed in series to meet the conventional film specifications of 300 mm wafers. The technology can benefit from the use of non-metallic mixers to avoid metal contamination in semiconductor manufacturing.

[0037] The two-stage embodiment can be used for some applications, but the internal volume of the mixer may be too large for applications that require dynamic changes in chemical content during distribution. Some photoresist chemicals can be very expensive. This expense has prompted manufacturers to reduce the distribution volume size to well below 1ml. Dynamically changing concentrations are a means to reduce the photoresist distribution volume. The volume from the point where the two chemicals are first mixed to the nozzle output represents the volume that must be displaced within the distribution to output the change in concentration. If this volume is too large, the distribution may end before the change can reach the nozzle output.

[0038] Single-stage embodiment Figure 3 . Two supply lines provide the flow of two chemicals from their corresponding supply lines and / or capsule units. These supply lines can be clamped in place by caps connected using flared tubes or by using other connection techniques. The flow path then enters the base block. The base block using PCTFE (polychlorotrifluoroethylene) is beneficial because of its chemical resistance and higher strength compared to Teflon or PFA (perfluoroalkoxyalkane). The mixer or mixing body can be formed of quartz and inserted into the base block. In the case where both the base block and the mixer are made of relatively hard materials, a softer compliant material (such as Teflon) can be used as a gasket between the faces. Grooves can be machined in the faces of the quartz mixer to help seal. The quartz mixer can be held in place and sealed by a compression screw or other attachment mechanism screwed into the base block. Such a screw can also be made of PCTFE to provide strength to the screw thread and transmit compression force for sealing. A second Teflon gasket can be used between the two parts. In some embodiments, the Teflon gasket can be a separate piece. Alternatively, they can be fused to quartz or mating PCTFE parts for easy assembly.

[0039] Alignment pins for the upper gasket and the quartz mixer can be used to ensure that these parts are properly aligned without restricting flow. The clamping screw can also conveniently provide a receiving thread for a conventional nozzle. This assembly is relatively compact. By way of non-limiting example, the quartz mixer can be 16.35 mm long and have a diameter of 8.8 mm. The volume of the mixer chamber is approximately 0.017 ml. The flow axis through the gasket and the clamping screw has a volume of approximately 0.012 ml. The flow axis through the conventional nozzle is approximately 0.020 ml, which can optionally be reduced. From the first mixing point to the nozzle output, there is a flow path volume of approximately 0.049 ml, which allows concentration changes within a 0.2 ml to 2 ml distribution range.

[0040] like Figure 4A , Figure 4B As shown, the mixer component is implemented as an integral component incorporating an upper portion that separates the two flow inputs and directs them to four inputs of the lower mixer section. In other embodiments, additional inputs may be used to increase the flow rate, depending on the specified end use or desired flow rate. Each of the four channels feeds into a central mixing chamber through a narrow tangential slot. The slot width can be manufactured from 60μm wide to 90μm wide. The channels can be approximately 5mm high. The quartz mixer can be formed by additive manufacturing or etching, etc. For example, internal channels can be etched into the interior of a quartz piece via a laser and chemical etching process. The upper section and the lower section can be manufactured as separate pieces and fused together to form a single piece. The quartz mixer can be formed by stacking components such as Figure 4A , Figure 4B Mixer components of those shown are used to achieve an increased volume flow. Stacking mixer components is also equivalent to increasing the channel height. It is also possible to increase the channel height directly. If more flow is required, the mixer units can also be positioned in parallel.

[0041] In an alternative configuration, the mixers are assembled as stacked mixers where the mixers are etched through silicon wafers which are then stacked and interlaced with PTFE gaskets. Figure 5A and Figure 5B This assembly is shown. Assembling a microfluidic slot mixer with a set of disks can achieve slot widths down to 10 microns and less.

[0042] In another embodiment, the tank mixers can be split in the z-axis to allow for 2D diffusion. For example, Figure 6 A cross section of a slot is shown, which is rectangular. By dividing this rectangle into a series of square or smaller slots, the fluid can be diffused vertically as well as horizontally. Such inputs can be staggered, alternated or used to replace a single rectangular slot. In addition, a first input can be staggered with a second input.

[0043] Reference now Figure 7 , showing the entire distribution system. Figure 7 In , the mixer is called a concentration tuner. Not all components are necessary for a tool production implementation of this system, so many options and variations are expected.

[0044] Therefore, various methods herein can mix chemicals in dynamically changing, staged or static ratios. One or more capsule-based fluid delivery pipelines can be used. Fluids can be pre-blended using a microfluidic mixer and then maintained for distribution. The second fluid can be pulsed into the first fluid. Various mixing modes can be configured. The quartz mixer can be positioned near the distribution nozzle. For a cylindrical mixing chamber, a conical member can be filled in the fluid dead zone at the top of the chamber. Using the technology herein, the nozzle tip can be reduced from 20mm to 3mm. Pre-mixed resists can be used in one pipeline, where additional solvents are mixed to help uniformity.

[0045] Uniformity in this article can refer to the variation in thickness of a given film from the edge of the wafer to the center of the wafer. In other words, the techniques in this article help achieve flatter films. For example, a given film thickness target is 70nm, but at the edge of the wafer, the thickness can be a few nanometers shorter at the edge. Thickness uniformity can be maintained by reducing the amount of resist that falls off at the outer edge, but using the blending techniques in this article, such as mixing in pulses of solvent during dispensing. Other techniques can use pressure-based valve timing with various types of pumps. Therefore, uniformity of resist thickness across the wafer can be achieved in this article.

[0046] Other aspects of the technology herein achieve improvements in uniformity and resist use. In the photolithography process, a photoresist is applied to a substrate (wafer) as a thin film. Conventional photoresists are three-component materials including the following: (1) a resin that acts as a binder and builds the mechanical properties of the film; (2) a sensitizer that is a photosensitive compound (PAC); and (3) a solvent that keeps the resin in a liquid state until it is applied to the substrate being processed. A typical spin coating process involves depositing a pool of liquid photoresist onto the center of the substrate, which is then rotated at a high speed (typically about 1500 rpm). The centripetal acceleration causes the resist to spread to the edge of the substrate and eventually leave the substrate, leaving a thin film of resist on the surface. The final film thickness and other characteristics will depend on the properties of the resist (viscosity, drying rate, percent solids, surface tension, etc.) and the parameters selected for the spin process. Factors such as final spin speed, acceleration, and solvent evaporation help determine how to define the characteristics of the coating film. The drying rate of the resist during the spin cycle depends primarily on the volatility of the solvent. The solvent component in the resist has a high evaporation rate, causing the film to dry before the resist reaches the edge of the substrate. To compensate, conventional systems allocate a much larger volume of resist than required to simply cover the wafer, resulting in a large amount of wasted material. Since the cost of liquid resists is extremely high, this creates a significant cost factor in semiconductor manufacturing.

[0047] Solvent evaporation has been identified as the leading factor in resist coverage, and it is an obstacle to further reducing consumption. The conventional method of reducing the amount of resist dispensed is to dispense a rinse solvent before spin coating the photoresist. The solvent dispensed before the resist is dispensed is referred to as "reduced resist consumption (RRC)" solvent. However, the RRC process has problems and limitations. The solvent evaporates easily and therefore the RRC solvent at the edge of the wafer may be less than at the center of the wafer, thereby causing insufficient resist coverage under a lower dispensed volume. In addition, the RRC process uses a large amount of solvent, which increases the cost of photolithography and produces serious chemical waste. In view of the above, it is still necessary to further reduce the amount of resist dispensed while improving the uniformity of coating thickness, so as to further reduce the cost of resist consumption and protect the environment by using less irritating chemicals.

[0048] Embodiments herein provide chemical dispensing equipment that reduces the amount of resist dispensed while producing high quality films. Use point-of-use dynamic dispensing using solvent / resist mixing. Some examples of solvents that can be used include, but are not limited to, PGMEA, OK73, PGEE, cyclohexanone, 4M2P, etc.

[0049] The RRC process can be reproduced in a single dispense, which has two benefits. First, using a single dispense reduces the overall process time, thereby increasing wafer throughput. Second, evaporation from the main solvent dispense helps saturate the local environment with solvent vapor, thereby reducing solvent evaporation from the resist dispense. This effect is enhanced by eliminating the delay between dispenses, as the solvent vapor has less time to diffuse from the wafer surface.

[0050] The hardware described herein implements a second application where dispensing begins with solvent only, providing a leading edge that will wet the wafer, followed by a brief blend from solvent to resist, and then pure resist dispensing. This approach provides a leading edge of resist that has experienced premature drying, an additional volume of solvent, such that the appropriate viscosity of the liquid is maintained by the time the flow reaches the edge of the wafer. The ratio of mixing can range from 1% to 99% solvent / resist or resist / solvent. Examples are 0.1 to 1.0cc of pure resist volume, see Figure 8 .

[0051] The hardware described herein can use a single chemical (resist, developer, rinse, metal or non-metal solution, organic or inorganic solution, etc.) concentration and evenly mix solvents or other chemicals to produce different viscosities or other liquid properties. In the case of photoresist, this can be used to produce a variety of resist thicknesses from a single liquid resist source. In addition, this concentration can be dynamically changed during dispensing to produce any desired effect.

[0052] The hardware described herein can be used to provide variable mixing within a dispense to reduce the adverse effects of chemistry changing too quickly, such as eliminating the negative effects of rapid pH changes during a TMAH / DI aqueous photoresist development process. When photoresist developer is rinsed from a wafer with pure DI water, photoresist residue may be left behind. The rapid drop in pH level causes some of the dissolved resist to precipitate out of solution, leaving resist residue on the wafer. This is avoided by the techniques described herein (see Fig. 9A , Fig. 9B ).

[0053] The hardware described herein enables the implementation of chemical mixtures and solutions that were previously not usable in production due to the fact that the solutions were unstable and reacted, decomposed, or precipitated out of solution in a very short time. By mixing the reactive components directly at the point of use, these chemicals can now be distributed in production without regard to the shelf life of the chemicals.

[0054] The embodiments described herein can be used to uniformly mix more than two chemicals simultaneously. In addition, any combination or sequence of mixed or pure chemicals can be provided within a single dispense to tune any specific film property, such as thickness uniformity, global and local wafer flattening, adjustment of surface interactions, conformal coating, etc.

[0055] In the foregoing description, specific details have been set forth, such as the specific geometry of the processing system and the description of the various components and processes used therein. However, it should be understood that the technology herein can be practiced in other embodiments that are separated from these specific details, and these details are for the purpose of explanation rather than limitation. The embodiments disclosed herein have been described with reference to the accompanying drawings. Similarly, for the purpose of explanation, specific numbers, materials, and configurations have been proposed in order to provide a thorough understanding. However, embodiments can be practiced without these specific details. Components having substantially the same functional structure are represented by similar reference numerals, and therefore any redundant description can be omitted.

Claims

1. A device for dispensing a fluid, the device comprising: a mixer configured to receive at least two fluids for mixing, the mixer being a microfluidic mixer configured to combine the at least two fluids using a slot-shaped fluid conduit; a nozzle positioned proximate the mixer to receive the mixed fluid for dispensing; a first fluid supply line connected to the mixer and configured to controllably supply a first process fluid into the mixer, the first fluid supply line comprising an elongated bladder defining a linear fluid flow path and configured to expand laterally and collect a charge of the first process fluid and contract laterally to deliver a selected volume of the first process fluid to the mixer; a second fluid supply line connected to the mixer and configured to controllably supply a second process fluid into the mixer to deliver a selected volume of the second process fluid to the mixer; as well as a controller configured to dynamically control the delivery of the first process fluid and the second process fluid independently of each other, wherein the apparatus has a fluid conduit volume of less than 0.1 ml between the point of mixing of each process fluid and the nozzle outlet, The mixer is positioned within 30 mm of the dispensing nozzle outlet. wherein the mixer comprises one or more first inlets for receiving the first process fluid and one or more second inlets for receiving the second process fluid, the mixer transforms the fluid flow path of each process fluid into a slot-shaped flow path, and Each slot-shaped fluid conduit has a height dimension that is at least ten times greater than a width dimension.

2. The device according to claim 1, wherein: The mixer includes a cylindrical mixing chamber that receives at least one slot-shaped fluid conduit for each process fluid and directs each process fluid along a circumference of the cylindrical mixing chamber.

3. The device of claim 2, wherein: The mixer is configured to direct each process fluid to mix within the cylindrical mixing chamber, which is a spiral flow.

4. The device of claim 1, wherein: The mixer joins these slot-shaped fluid conduits together to form a slot-shaped mixing conduit.

5. The device of claim 4, wherein: The slotted mixing conduits are sized to prevent turbulent mixing flow.

6. The device of claim 4, wherein: The slotted mixing conduits are sized to provide laminar flow of each process fluid such that the process fluids mix by diffusion.

7. The device of claim 1, wherein: The nozzle includes an inlet for receiving a mixed process fluid from the mixer, and a nozzle tip for dispensing the mixed process fluid onto a substrate.

8. The device of claim 7, wherein: The mixer is positioned less than 25 mm from the nozzle.

9. The device of claim 1, wherein: The mixer has a length of less than 40 mm and a width of less than 20 mm, and wherein the nozzle has a length of less than 30 mm.

10. The device of claim 1, wherein: The fluid supply line, the mixer and the nozzle are all aligned to provide laminar flow from the fluid supply line to the nozzle outlet.

11. The device of claim 1, wherein: The microfluidic mixer includes a slot-shaped fluid conduit having a width of less than 200 microns and a length of less than 15 millimeters.

12. The apparatus of claim 1, wherein: The mixer is made of quartz.

13. The apparatus of claim 1, wherein: The mixer is formed by combining a plurality of disks.

14. The apparatus of claim 1, wherein: The total internal volume of the fluid conduits of the mixer is less than 0.1 ml.

15. The apparatus of claim 1, wherein: The mixer includes grooves formed in the quartz interface to enable the components to be sealed together to maintain laminar flow.

16. A method for dispensing a fluid, the method comprising: mixing a first process fluid with a second process fluid proximate the dispensing nozzle using a mixer, the mixer being a microfluidic mixer configured to combine at least two fluids using a slotted fluid conduit; supplying a first process fluid into the mixer using a first fluid supply line configured to control the volume of the first process fluid entering the mixer using an elongated bladder defining a linear fluid flow path, the elongated bladder configured to expand laterally and collect a charge of the first process fluid and to contract laterally to deliver a selected volume of the first process fluid to the mixer; supplying a second process fluid to the mixer using a second fluid supply line, the second fluid supply line configured to control a volume of the second process fluid delivered to the mixer; as well as dispensing a mixed process fluid onto a substrate via the dispensing nozzle, wherein the mixer mixes the first process fluid with the second process fluid near the dispensing nozzle such that a volume of the mixed process fluid between the mixer and an outlet of the dispensing nozzle is less than 0.1 ml, The mixer is positioned within 30 mm of the dispensing nozzle outlet. wherein the mixer comprises one or more first inlets for receiving a first process fluid and one or more second inlets for receiving a second process fluid, the mixer transforming the fluid flow path of each process fluid into a slot-shaped flow path, and Each slot-shaped fluid conduit has a height dimension that is at least ten times greater than a width dimension.

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