Background

[0001] A fluid dispensing system can dispense fluid towards a target. In some examples, a fluid dispensing system can include a printing system, such as a two- dimensional (2D) printing system or a three-dimensional (3D) printing system. A printing system can include printhead devices that include fluidic actuators to cause dispensing of printing fluids.

Brief Description of the Drawings

[0002] Some implementations of the present disclosure are described with respect to the following figures.

[0003] Fig. 1 is a block diagram of a fluidic die including an interspersed arrangement of fluidic cells and low-voltage circuit elements, along with high-voltage circuit elements placed outside a fluidics region, according to some examples.

[0004] Fig. 2 is a schematic sectional view of a portion of a fluidic die including low-voltage circuit element layers and layers of a fluidic cell, according to some examples.

[0005] Fig. 3 is a block diagram of a portion of a fluidic die including an interspersed arrangement of fluidic cells and low-voltage circuit elements, along with high-voltage circuit elements placed outside a fluidics region, according to some examples.

[0006] Fig. 4 is a block diagram of a fluidic die including multiple interspersed arrangements of fluidic elements and low-voltage circuit elements, along with multiple blocks of high-voltage circuit elements, according to further examples.

[0007] Fig. 5 is a flow diagram of a process of forming a fluidic die, according to some examples. [0008] Fig. 6 is a block diagram of a fluidic die according to further examples.

[0009] Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.

Detailed Description

[0010] In the present disclosure, use of the term "a," "an", or "the" is intended to include the plural forms as well, unless the context clearly indicates otherwise. Also, the term "includes," "including," "comprises," "comprising," "have," or "having" when used in this disclosure specifies the presence of the stated elements, but do not preclude the presence or addition of other elements.

[0011 ] A fluid dispensing device can include fluidic actuators that when activated cause dispensing (e.g., ejection or other flow) of a fluid. For example, the dispensing of the fluid can include ejection of fluid droplets by activated fluidic actuators from respective nozzles of the fluid dispensing device. In other examples, an activated fluidic actuator (such as a pump) can cause fluid to flow through a fluid conduit or fluid chamber. Activating a fluidic actuator to dispense fluid can thus refer to activating the fluidic actuator to eject fluid from a nozzle or activating the fluidic actuator to cause a flow of fluid through a flow structure, such as a flow conduit, a fluid chamber, and so forth.

[0012] In some examples, the fluidic actuators include thermal-based fluidic actuators including heating elements, such as resistive heaters. When a heating element is activated, the heating element produces heat that can cause vaporization of a fluid to cause nucleation of a vapor bubble (e.g., a steam bubble) proximate the thermal-based fluidic actuator that in turn causes dispensing of a quantity of fluid, such as ejection from an orifice of a nozzle or flow through a fluid conduit or fluid chamber. In other examples, a fluidic actuator may be a deflecting-type fluidic actuator such as a piezoelectric membrane based fluidic actuator that when activated applies a mechanical force to dispense a quantity of fluid.

[0013] In examples where a fluid dispensing device includes nozzles, each nozzle can include an orifice through which fluid is dispensed from a fluid chamber, in response to activation of a fluidic actuator. Each fluid chamber provides the fluid to be dispensed by the respective nozzle. In other examples, a fluid dispensing device can include a microfluidic pump that has a fluid chamber.

[0014] Generally, a fluidic actuator can be an ejecting-type fluidic actuator to cause ejection of a fluid, such as through an orifice of a nozzle, or a non-ejecting- type fluidic actuator to cause displacement of a fluid.

[0015] In some examples, a fluid dispensing device can be in the form of a fluidic die. A “die” refers to an assembly where various layers are formed onto a substrate to fabricate circuitry, fluid chambers, and fluid conduits. Multiple fluidic dies can be mounted or attached to a support structure.

[0016] In some examples, a fluidic die can be a printhead die, which can be mounted to a print cartridge, a carriage assembly, and so forth. A printhead die includes nozzles through which a printing fluid (e.g., an ink, a liquid agent used in a 3D printing system, etc.) can be dispensed towards a target (e.g., a print medium such as a paper sheet, a transparency foil, a fabric, etc., or a print bed including 3D parts being formed by a 3D printing system to build a 3D object).

[0017] A fluidic die includes fluidic elements and circuitry that control fluid dispensing operations of the fluidic elements. The circuitry includes logic that is responsive to address signals and control signals to produce output signals that control switching elements used for activating respective fluidic actuators in the fluid elements.

[0018] A fluidic element includes flow structures that provide for fluid flow in the fluidic element. Examples of flow structures include any or some combination of the following: a fluid chamber that stores a fluid to be dispensed by the fluid element, an orifice through which fluid can pass from the fluid chamber to a region outside the fluid chamber, a fluid feed hole that is used to communicate fluid between a fluid flow conduit and the fluid chamber in the fluid element, a fluid channel to transport fluid, and a fluidic actuator that when activated causes dispensing of a fluid by the fluid element (a fluidic actuator can include a thermal-based fluidic actuator or a deflecting-type fluidic actuator, for example).

[0019] In some examples, a fluidic die includes fluidic elements contained in fluidic architecture regions that do not include circuitry with active devices. In such examples, the fluidic die is partitioned into the fluidic architecture regions and circuit regions that are outside of the fluidic architecture regions. The circuit regions include circuit elements that include active devices.

[0020] As used here, an "active device" can refer to a device that can be switched between different states, such as an on state at which electrical current flows through the device, and off state at which electrical current does not flow through the device (or the amount of electrical current flow is negligible or below a specified threshold). An example of an active device is a transistor, such as a field effect transistor (FET). A transistor has a gate that is connected to a signal ("gate signal") to control the state of the transistor. When the gate signal is at an active level (e.g., a low voltage or a high voltage depending on the type of transistor used), the transistor turns on to conduct electrical current between two other nodes of the transistor (e.g., a drain node and a source node of an FET). On the other hand, if the gate signal is at an inactive level (e.g., a high voltage or a low voltage depending on the type of transistor used), then no electrical current flows through the transistor (or the amount of electrical current through the transistor is negligible or below a specified threshold). In some cases, the gate signal to the transistor can be set at an intermediate level between the active level or the inactive level, which causes the transistor to conduct an intermediate amount of electrical current.

[0021 ] Another example of an active device is a diode. If the voltage across two nodes of the diode exceeds a threshold voltage, then the diode turns on to conduct electrical current through the diode. However, if the voltage across that the two nodes of the diode is less than the threshold voltage, and the diode remains off.

[0022] Partitioning a fluidic die between fluidic architecture regions and circuit regions may simplify the interface between the circuit elements and the fluidic elements, or may be performed because of the arrangement of fluid feed slots in the fluidic die. A fluid feed slot refers to a fluid conduit that may run along an entire actuator column of the fluidic die. The fluid feed slot is used to carry fluid to and from the fluidic elements of the fluidic die.

[0023] Certain types of fluidic dies may employ a sparse arrangement of fluidic elements (the fluidic elements are arranged in patterns of lower density than fluidic elements in other fluidic dies). If a fluidic die has a sparse arrangement of fluidic elements, then the fluidic architecture regions would consume a larger area of the fluidic die than fluidic architecture regions of a fluidic die with a denser arrangement of fluidic elements. Given the same size of a fluidic die and assuming a same quantity of fluidic elements is used (compared to another fluidic die with a denser arrangement of fluidic elements), the larger fluidic architecture regions of the sparse arrangement would result in smaller circuit regions in the fluidic die, which leads to greater compaction of circuit elements. In some cases, there may not be sufficient space for circuit elements in a fluidic die with a sparse arrangement of fluidic elements.

[0024] Circuit elements of a fluidic die can include high-voltage circuit elements and low-voltage circuit elements. The low-voltage circuit elements are operable at a first power supply voltage, and the high-voltage circuit elements are operable at a second power supply voltage greater than the first power supply voltage. A "power supply voltage" refers to a voltage provided to power circuit elements. For example, a low-voltage circuit element powered by the first power supply voltage can produce an output based on the first power supply voltage. For example, the output can be driven to the first power supply voltage when the low-voltage circuit element is activated (e.g., when a transistor is turned on). In this example, the low-voltage circuit element is able to transition between a low voltage (e.g., zero volts or V) and the first power supply voltage. Alternatively, the output can be driven to a voltage level that is a specified amount less than the first power supply voltage when the low-voltage circuit element is activated (e.g., a diode when turned on produces an output that is a threshold voltage less than the first power supply voltage).

[0025] Similarly, a high-voltage circuit element powered by the second power supply voltage can produce an output based on the second power supply voltage. For example, the high-voltage circuit element is able to transition between a low voltage (e.g., zero volts) and the second power supply voltage. Alternatively, the high-voltage circuit element when turned on produces an output that is a specified amount less than the second power supply voltage.

[0026] In some examples, the second power supply voltage is greater than 15 V, or greater than 20 V, or greater than 30 V, and so forth. In some examples, the first power supply voltage is between 3 V and 10 V, or between 3 V or 7 V, or between 3V and 5V, and so forth.

[0027] In accordance with some implementations of the present disclosure, as shown in Fig. 1 , a fluidic die 102 includes fluidic elements in the form of fluidic cells 104. A "fluidic cell" refers to a collection of flow structures, and the fluidic cell can be repeated across the fluidic die 102, such as to form an array. The fluidic cells 104 are interspersed with low-voltage circuit elements (represented as blocks labeled with "LVC" in Fig. 1 ) along multiple different axes across a substrate (of the fluidic die) on which the fluidic elements and the low-voltage circuit elements are commonly formed. Fluidic cells are interspersed with low-voltage circuit elements if along a given axis, successive fluidic cells are separated by low-voltage circuit element(s), and successive low-voltage circuit elements are separated by fluidic cell(s).

[0028] In addition, high-voltage circuit elements (arranged in blocks labeled with "HVC") that include active devices are placed in a region outside of a fluidics boundary 180 defining a space in which the fluidic cells 104 and the low-voltage circuit elements are placed. None of the high-voltage circuit elements in the blocks HVC are placed within the fluidics boundary 180. Note that in some examples, other high-voltage circuit elements may be placed at any or some combination of the four sides of the fluidics boundary 180, just within the fluidics boundary 180. Also, other low-voltage circuit elements may be placed on the substrate 110 outside the fluidics boundary 180.

[0029] In some examples, the active devices of the high-voltage circuit elements include power transistors 182 (e.g., power FETs) that when activated drive signals to activate respective fluidic actuators 115 in the fluidic cells 104. A power transistor when activated can drive a signal to the second power supply voltage, which is provided to a respective fluidic actuator 115 (e.g., a resistive heater).

[0030] A high-voltage circuit element such as a power transistor has an area efficiency that depends upon a physical structure or layout of integrated circuit layers used to form the power transistor. The area efficiency can be expressed as an amount of electrical current per unit area, which represents how much electrical current can be driven by the power transistor given an area of the layers used to form the power transistor. A power transistor has a better area efficiency if the area of the layers used to form the power transistor is a single uninterrupted region as compared to an area formed using discrete sub-areas. Since the regions without flow structures between the fluidic cells 104 within the fluidics boundary 180 are relatively small (as compared to regions of the fluidic die 102 outside the fluidics boundary 180, arranging the high-voltage circuit elements outside the fluidics boundary 180 can achieve more efficient performance of the high-voltage circuit elements. Placing the high-voltage circuit elements in the regions between the fluidics cells 104 may involve breaking up each high-voltage circuit element into discrete sub-areas, which may cause a reduced efficiency of the high-voltage circuit element.

[0031 ] Low-voltage circuit elements are generally smaller than high-voltage circuit elements, and thus are able to fit more effectively in the regions between the fluidic cells 104 within the fluidics boundary 180. [0032] The multiple different axes along which the fluidic cells 104 are interspersed with the low-voltage circuit elements include a first axis 106 and a second axis 108 that is substantially orthogonal to the first axis 106. The first axis 106 and the second axis 108 are substantially orthogonal if the first axis 106 has an angle with respect to the second axis 108 that is in any of the following ranges: between 45° and 135°, between 60° in 120°, between 75° and 115°, and so forth.

[0033] Each low-voltage circuit element LVC includes an active device or multiple active devices. In some examples, active devices of a low-voltage circuit element LVC can be interconnected to provide a logical operation, such as a logical AND, a logical OR, a logical inversion, and so forth. Active devices of a low-voltage circuit element LVC can also be used to perform other types of operations, such as to provide a latch, a register, or another storage element, to provide a variable resistance, and so forth. As an example, a low-voltage circuit element LVC can be part of control circuitry of the fluidic die 102, where the control circuitry is used to control an operation of the fluidic cells 104 (and more specifically, the fluidic actuators 115 in the fluidic cells 104), in response to input signals, such as address signals, control signals, data, and so forth. The input signals may be received from a controller of fluid dispensing system, such as a print controller of a printing system.

[0034] In further examples, the active devices of a low-voltage circuit element LVC can be used to implement analog circuitry. As noted above, examples of active devices include transistors and diodes, or any other device that can be switched between different states in response to an input signal.

[0035] In the example of Fig. 1 , the fluidic cells 104 are arranged in a two- dimensional array, along the first axis 106 and the second axis 108. In other examples, the array of fluidic cells 104 can have a different pattern; for example, instead of a row or column that is generally parallel to the axis 106 or 108, respectively, a line of fluidic cells 104 may be slanted with respect to the axis 106 or 108. Moreover, instead of the fluidic cells 104 having a regular pattern, the fluidic cells 104 may have an irregular pattern or even a random pattern across the substrate 110 of the fluidic die 102. [0036] In some examples, a first quantity of low-voltage circuit elements interspersed in regions between the fluidic cells 104 along the axis 106 is greater than a specified number (e.g., 10, 20, etc.), and a second quantity of low-voltage circuit elements interspersed in regions between the fluidic cells 104 along the axis 108 is greater than a specified number (e.g., 10, 20, etc.).

[0037] Each fluidic cell 104 includes a respective fluid feed hole 112 and a fluid chamber 114 into which a fluid can be fed through the fluid feed hole 112, in the example of Fig. 1 . The fluidic cell 104 can also include a fluidic actuator 115, which when activated causes the fluid in the fluid chamber to be dispensed through an orifice (not shown in Fig. 1) of the fluidic cell 104. In further examples, a fluidic cell 104 can include multiple fluid feed holes and/or multiple orifices.

[0038] Although specific flow structures have been identified as being part of the fluidic cell 104, it is noted that in other examples, additional or alternative types of flow structures can be included in each fluidic cell 104.

[0039] In the example of Fig. 1 , an array of fluid feed holes 112 is arranged in multiple dimensions (e.g., along the axes 106 and 108). The array of fluid feed holes 112 include distinct fluid feed holes that extend along a first dimension of the multiple dimensions, and distinct fluid feed holes that extend along a different second dimension of the multiple dimensions. "Distinct" fluid feed holes refer to fluid feed holes that are individually separate from one another, as opposed to a fluid feed slot that can extend a relatively long length to feed multiple fluidic cells, such as a column of fluidic cells. The fluid feed holes 112 are used to communicate fluid with respective fluid chambers of the fluidic cells 104.

[0040] The fluidic die 102 has multiple outer edges 102-1 , 102-2, 102-3, and 102- 4, which collectively form a general rectangle (when viewed from the top or bottom) in the example of Fig. 1 . An "outer edge" of a fluidic die refers to a segment of an outermost boundary of the fluidic die 102. In other examples, the fluidic die 102 can have different shapes. [0041 ] In some examples, either the first dimension or the second dimension of the multiple dimensions along which the array of fluid feed holes 112 is arranged can be parallel to an outer edge (one of 102-1 , 102-2, 102-3, and 102-4) of the fluidic die 102. In further examples, both the first dimension and the second dimension are parallel to respective outer edges of the fluidic die 102.

[0042] In addition, each of multiple fluid feed holes along the first dimension (e.g., along the axis 106) is distinct from multiple fluid feed holes along the second dimension (e.g., along the axis 108). For example, in the first row 150 of the array of fluidic cells 104 shown in Fig. 1 , each of fluid feed holes 112 in the fluidic cells 104 in the second column 158 and the third column 160 is distinct from multiple fluid feed holes 112 in the fluidic cells 104 in the second row 152 and last row 154 of the first column 156 of the array. Even though there is a common fluidic cell 104 at the intersection of the first row 150 and the first column 156, the first row 150 has multiple fluidic cells (in columns other than the first column 156) that are distinct from multiple fluidic cells in the first column 156 (in rows other than the first row 150).

[0043] In some examples, the fluidic die 102 can be mounted on a support structure (e.g., a print cartridge, a carriage, etc.), which is relatively moveable with respect to a target to which fluid of the fluidic die 102 is to be dispensed. For example, the target can be a print substrate onto which printing fluid is to be dispensed in a 2D printing system, or a 3D build part onto which liquid agents are to be dispensed during a 3D build operation of a 3D printing system. The fluidic die 102 is relatively moveable with respect to the target if either or both of the fluidic die 102 and the target is (are) moveable. In some examples, the fluidic die 102 is relatively moveable with respect to the target along a direction that is parallel to either axis 106 or 108.

[0044] Regions that are without flow structures are provided between successive fluidic cells 104 along both the first axis 106 and the second axis 108. Such regions are not used by the fluidic cells 104 for fluid flow. The low-voltage circuit elements are placed in the regions between the fluidic cells 104. As a result, the low-voltage circuit elements are interspersed with the fluidic cells 104 along both the axes 106 and 108. The elements of the fluidic cells 104 being interspersed with the low- voltage circuit elements result in an alternating arrangement of fluidic elements and low-voltage circuit elements along the different axes 106 and 108.

[0045] By alternating the fluidic elements with the low-voltage circuit elements in multiple different axes, more space on the substrate 110 of the fluidic die 102 is provided to accommodate the low-voltage circuit elements while still allowing for a sparse arrangement of the fluidic cells 104, in some examples.

[0046] The fluidic cells 104, the low-voltage circuit elements, and the high- voltage circuit elements are formed on a common substrate, i.e. , the substrate 110 of the fluidic die 102. The substrate 110 can be a silicon substrate, or a substrate formed of another semiconductor material or a different material. Forming the fluidic cells 104, the low-voltage circuit elements, and the high-voltage circuit elements on a common substrate refers to forming layers of the fluidic cells 104, the low-voltage circuit elements, and the high-voltage circuit elements as part of an integrated circuit processing flow for a single integrated circuit device, which in Fig. 1 is the fluidic die 102. Circuit elements (low-voltage and high-voltage circuit elements) and fluidic cells 104 formed on different substrates, such as being part of different integrated circuit devices formed using different integrated circuit process flows, would not be considered to be formed on a common substrate.

[0047] Fig. 2 is a schematic sectional view of a portion of a fluidic die 200 attached to an interposer 240 or another type of structure, according to further examples. The fluidic die 200 includes layers 206, 208, 218, and 224. A "layer" (any of 206, 208, 218, and 224) can include a single layer or multiple layers, possibly formed of different materials. The layers 224 and 218 make up a substrate for the fluidic die 200. The layers 224 and 218 can include an epoxy-based photoresist (e.g., Sil-8), silicon, another semiconductor material, or a different material.

[0048] Fig. 2 shows layers of a fluidic cell 204 and a low-voltage circuit element (202 represents active low-voltage circuit element layers, such as layers of an active device or multiple active devices). The low-voltage circuit element layers 202 can include any or some combination of metal layers, polysilicon layers, doped regions, and so forth. Doped regions can be formed into the layer 218. Metal layers and polysilicon layers of active devices can be formed over the doped regions. A thin film interconnect layer or layers 230 (including a metal or another electrically conductive material) can be formed over the layer 218, where the thin film interconnect layer 230 can form an electrical contact or via to electrically connect to an active device.

[0049] The fluidic cell 204 can be arranged in similar manner as the fluidic cell 104 of Fig. 1 (i.e., multiple fluidic cells 204 can be arranged in an array along multiple axes, such as the axes 106 and 108 shown in Fig. 1 ). The low-voltage circuit elements formed using low-voltage circuit element layers 202 can also be interspersed with the fluidic cells 204 along multiple different axes.

[0050] The fluidic cell 204 includes an orifice layer 206 in which an orifice 207 (or multiple orifices) is (are) formed. A chamber layer 208 is provided under the orifice layer 206, and the chamber layer 208 defines a fluid chamber 210. The layers 206 and 208 include any of various different types of materials, such as epoxy, silicon, and so forth.

[0051 ] A fluidic actuator 212 is formed over the layer 218 in the fluid chamber 210. If the fluidic actuator is a resistive heater, the fluidic actuator 212 can be formed using a thin film of an electrically resistive material (such as tungsten-silicon nitride, polysilicon or any other material that exhibits electrical resistivity). Activation of the fluidic actuator 212 causes fluid in the fluid chamber 210 to be expelled through the orifice 207.

[0052] In some examples, the low-voltage circuit element layers 202 are formed on the substrate (including layers 224 and 218) of the fluidic die 200 before various layers of the fluidic cell 204. A layer is on the substrate if the layer is directly on the substrate, or if the layer is supported by the substrate through other layer(s). The chamber layer 208 is formed over the layer 218 as well as over thin film layers (the thin film layer for the fluidic actuator 212 and the thin film interconnect layer 230). Thus, in Fig. 2, the low-voltage circuit element layers 202 are formed over the substrate (including layers 224 and 218) prior to the layers 208 and 206 for the fluidic cell 204. After the low-voltage circuit element layers 202 are formed over the substrate, the thin film layers (the thin film layer for the fluidic actuator 212 and the thin film interconnect layer 230) are formed, followed by the fluidic cell layers 208 and 206 over the active circuit element layers 202.

[0053] In the example of Fig. 2, two fluid feed holes 214 and 216 are formed in a feed hole layer 218 (by etching the feed hole layer 218 to form the fluid feed holes, for example). The fluid feed hole 214 is an inlet fluid feed hole that allows fluid to flow into the fluid chamber 210. The fluid feed hole 216 is an outlet fluid feed hole from which fluid in the fluid chamber 210 flows. The inlet fluid feed hole 214 is in communication with a high pressure chamber 220, and the outlet fluid feed hole 216 is in communication with a low pressure chamber 222. The high pressure chamber 220 and the low pressure chamber 222 are formed in a layer 224 (by etching the layer 224 to form the chambers 220 and 222, for example). The high pressure chamber 220 is divided from the low pressure chamber 222 by a wall 221 of the layer 224.

[0054] The pressure in the high pressure chamber 220 and the pressure in the low pressure chamber 222 can be controlled by respective pressure regulators (not shown). The high pressure chamber 220 has a pressure that is higher than the pressure of the low pressure chamber 222.

[0055] The arrangement of the fluidic cell 204 allows for fluid recirculation along fluid path 226. Fluid can flow from the high pressure chamber 220 into the inlet fluid feed hole 214, which is then passed to the fluid chamber 210. The fluid exits from the fluid chamber 210 through the outlet fluid feed hole 216 to the low pressure chamber 222.

[0056] Recirculation can be performed to carry any contaminants or nonhomogeneity of the fluid in the fluid chamber 210 out of the fluid chamber 210 to be replaced by fresh and uncontaminated fluid. In other examples, recirculation of fluid through the fluid chamber 210 can be performed for other purposes

[0057] Although a specific arrangement is shown in Fig. 2 to enable fluid recirculation in the fluidic cell 204, recirculation can be enabled using other arrangements in other examples.

[0058] The low-voltage circuit element layers 202 are formed in a region 250 that is devoid of flow structures of the fluid cell 204. The region 250 is between successive fluidic cells 204 in each of multiple axes, such as axes 106 and 108 shown in Fig. 1 .

[0059] The interposer 240 is a structure that is attached to the fluidic die 200.

The interposer 240 can include fluid flow channels (not shown) to communicate fluid with the chambers 220 and 222. The interposer 240 can be a die that is separate from the fluidic die 200.

[0060] Fig. 3 is a block diagram of a portion of a fluidic die according to further examples, in which fluidic cells 304 and low-voltage circuit elements (represented by blocks labeled with "LVC") are interspersed along different axes 306 and 308. The fluidic cells 304 in Fig. 3 have a stepped arrangement with respect to the axis 306.

Thus, unlike the arrangement of Fig. 1 where the fluidic cells 104 are aligned in rows and columns that are generally parallel to the respective axes 106 and 108, the arrangement of the fluidic cells 304 in Fig. 3 is a stepped arrangement in which the fluidic cells 304 are stepped downwardly with respect to the axis 306 such that a line of fluidic cells 304 (extending generally along 320) is not parallel to the axis 306.

The line (320) of fluidic cells is angled (slanted) with respect to the axis 306. In the stepped arrangement, each successive fluidic cell 304 along the line 320 is shifted downwardly (along the axis 308) from the immediately preceding fluidic cell 304 along the line 320, so that the line 320 of fluidic cells 304 progressively step downwardly along the axis 308 relative to the axis 306. [0061] Along the orthogonal axis 308, the fluidic cells 304 are lined up generally parallel to the axis 308.

[0062] Each fluidic cell 304 includes fluid feed holes 310 and 312 (e.g., similar to the fluid feed holes 214 and 216 shown in Fig. 2). Also, each fluidic cell 304 includes orifices 314 and 316. For example, the orifice 314 is larger than the orifice 316.

[0063] The fluidic cells 304 and the low-voltage circuit elements are arranged in an interspersed manner within a fluidics boundary 330. High-voltage circuit elements (represented by a block labeled with "HVC") are arranged outside the fluidics boundary 330.

[0064] Fig. 4 is a block diagram of a fluidic die 400 according to further examples. The fluidic die 400 includes a first interspersed arrangement 402-1 of fluidic elements and low-voltage circuit elements, and a second interspersed arrangement 402-2 of fluidic elements and low-voltage circuit elements. Each interspersed arrangement 402-1 or 402-2 of fluidic elements and low-voltage circuit elements can be similar to the arrangement shown in any of Figs. 1 and 3.

[0065] The first interspersed arrangement 402-1 of fluidic elements and low- voltage circuit elements is included within a fluidics boundary 400-1 , and the second interspersed arrangement 402-2 of fluidic elements and low-voltage circuit elements is included within a fluidics boundary 400-2.

[0066] The fluidic die 400 further includes high-voltage circuit elements in blocks 404-1 , 404-2, 404-3, 404-4, and 404-5. Note that some of the blocks 404-1 , 404-2, 404-3, 404-4, and 404-5 may be omitted in further examples. The high-voltage circuit elements are placed outside each of the fluidics boundaries 400-1 and 400-2, such that none of the high-voltage circuit elements in the blocks 404-1 , 404-2, 404-3, 404-4, and 404-5 are placed in the fluidics boundary 400-1 , and none of the high- voltage circuit elements in the blocks 404-1 , 404-2, 404-3, 404-4, and 404-5 are placed in the fluidics boundary 400-2. [0067] Fig. 5 is a flow diagram of a process 500 of forming a fluidic die according to some examples of the present disclosure.

[0068] The process 500 includes forming (at 502) layers for first circuit elements and second circuit elements on a substrate, where each circuit element of the second circuit elements includes an active device, where the first circuit elements are operable at a first power supply voltage, and the second circuit elements operable at a second power supply voltage greater than the first power supply voltage.

[0069] The process 500 includes forming (at 504) layers for fluidic elements over the layers for the first and second circuit elements, where the fluidic elements are to dispense a fluid, an arrangement of the fluidic elements across the substrate has regions without flow structures between successive fluidic elements, and each fluidic element of the fluidic elements includes a fluidic actuator and a fluid chamber.

[0070] The process 500 includes interspersing (at 506) the first circuit elements in the regions between the fluidic elements along different axes of the fluidic die.

[0071] The process 500 includes placing (at 508) the second circuit elements in a region outside of a boundary defining a space in which the fluidic elements and the first circuit elements are placed.

[0072] The process 500 includes forming (at 510) an array of fluid feed holes in a plurality of dimensions to communicate the fluid with the fluidic elements, where each of multiple fluid feed holes along a first dimension of the plurality of dimensions is distinct from multiple fluid feed holes along a second dimension of the plurality of dimensions.

[0073] Fig. 6 is a block diagram of a fluidic die 600 according to further examples. The fluidic die 600 includes a substrate 602 and an arrangement of fluidic elements 604 to dispense a fluid, each fluidic element of the fluidic elements including a fluidic actuator 620 and a fluid chamber 622. The arrangement of fluidic elements 604 includes first fluidic elements along a first axis 606 across the substrate 602, and second fluidic elements along a different second axis 608 across the substrate 602.

[0074] Low-voltage circuit elements 610 are interspersed between the fluidic elements along each of the first axis 606 and the second axis 608, where each low- voltage circuit element is operable at a first power supply voltage and includes an active device, and where greater than 10 low-voltage circuit elements are arranged along the first axis 606 in first regions between successive first fluidic elements 604, and greater than 10 low-voltage circuit elements are arranged along the second axis 608 in second regions between successive second fluidic elements 604.

[0075] High-voltage circuit elements 630 are placed in a region outside of a fluidics boundary 632 defining a space in which the fluidic elements 604 and the low- voltage circuit elements 610 are placed, where each high-voltage circuit element 630 includes an active device operable at a second power supply voltage greater than the first power supply voltage. The fluidic elements 604, the low-voltage circuit elements 610, and the high-voltage circuit elements 630 are commonly formed on the substrate 602.

[0076] Interspersed arrangements of fluidic elements and low-voltage and high- voltage circuit elements according to some examples of the present disclosure may provide various benefits. For example, greater space is provided on the substrate of a fluidic die to accommodate circuit elements in a sparse arrangement of fluidic elements. Also, low-voltage circuit elements being placed closer to fluidic elements can reduce parasitic impedances in signals transmitted by the low-voltage circuit elements. Interspersing low-voltage circuit elements with fluidic elements allows for a greater density of the low-voltage circuit elements without increasing the overall size of a fluidic die. Also, placing high-voltage circuit elements outside a fluidics boundary containing an interspersed arrangement of fluidic elements and low- voltage circuit elements provides high-voltage circuit elements of greater efficiency.

[0077] In the foregoing description, numerous details are set forth to provide an understanding of the subject disclosed herein. However, implementations may be practiced without some of these details. Other implementations may include modifications and variations from the details discussed above. It is intended that the appended claims cover such modifications and variations.