At times, devices, such as semiconductor devices, may be attached to molded structures. The molded structure may have through holes or channels through which fluids and gasses (among other things) may travel. A number of processes exist for creating molded structures with through holes or channels. For instance, build up processes, such as lithography on dry film, may be used to create molded structures with through holes or channels. Substrate bonding and/or welding may also be used to yield molded structures with through holes or channels.
Various examples will be described below by referring to the following figures.
Reference is made in the following detailed description to accompanying drawings, which form a part hereof, wherein like numerals may designate like parts throughout that are corresponding and/or analogous. It will be appreciated that the figures have not necessarily been drawn to scale, such as for simplicity and/or clarity of illustration.
In the context of fluidic devices, such as printing fluid ejection devices, portions of the devices may be attached to supporting components. The supporting components may provide fluidic channels to enable printing fluid to flow to fluidic ejection dies of the fluidic ejection devices. In some cases, the supporting components may be made up of molding compounds and structures (referred to herein as molded devices or molded structures).
In addition to receiving fluids from supporting components, the fluidic ejection dies may receive electric signals from other components of the printing fluid ejection devices. For example, electric signals, such as in the form of current pulses, for controlling ejection of printing fluids may be transmitted to the fluidic ejection dies via wires or traces that enable an electrical connection between the fluidic dies and a controller of the printing fluid ejection devices.
Further, in some implementations, thermal energy, such as in the form of heat, may be directed away from the fluidic ejection dies via thermally-conductive components and/or fluids. For instance, the fluidic ejection dies may use the application of heat to small volumes of printing fluid to generate bubbles of gas and expulse controlled droplets of printing fluid. The application of heat, such as by pulses of current through a resistive element, may, in some cases, cause thermal energy to build in the fluidic ejection die. Thermally conductive components may therefore be used to carry the generated thermal energy away from the fluidic ejection dies.
At times, the components that enable propagation of both electric signals and thermal energy may have similar characteristics, such as being metals or metalloids. Therefore, for simplicity, the present description refers to electrically and/or thermally conductive components as thermo-electric or thermo-electrically conductive traces.
In some cases, in addition to embedded thermo-electrical traces, the molded components may include channels, slots, and/or through holes. Channels refer to voids within a molded component through which fluids, gasses, electromagnetic radiation (EMR) (e.g., visible light), and the like may propagate. Through holes refer to channels that have independent openings at one (or more) surfaces of a molded supporting structure, and through which fluids may flow. Slots refer channels through that have an opening at one surface of the molded supporting structure, but not necessarily two. For instance, a slot may lead to a fluid channel, which may lead to another slot and/or a through hole. For simplicity, the present disclosure uses the term “channel” in a general sense, which may also refer to a through hole or a slot, according to context.
To illustrate how one such example molded device with fluid channels may be used in conjunction with a fluidic die, the example of an inkjet printing device (e.g., for dispensing printing fluids, such as colorants or agents, by way of example) is discussed without limitation. To be clear, while the concepts of molded devices with channels may apply to an inkjet printing device, it should be appreciated that they may be relevant to other contexts, such as to microfluidic devices for biomedical applications, optical propagation devices such as for sensing or transmitting EMR, and gas sensing devices, by way of example.
Thus, for an example inkjet printing device, a fluid ejection device (e.g., a printhead) may be used to dispense printing fluids (e.g., inks, colorants, agents) on a substrate. The fluid ejection device may include a fluidic die having an array of fluid ejection nozzles through which droplets of printing fluid are ejected towards a substrate. The fluidic die may be attached to a molded device (e.g., a chiclet) with channels, through which the printing fluid may flow, such as towards and/or away from the fluidic die. As such, the molded device may operate in conjunction with the fluidic die to enable ejection of printing fluids, such as by delivering fluids to the fluidic die, recirculating fluids (e.g., to reduce pigment buildup), providing thermal protection to the fluidic die (e.g., pulling heat away from the fluidic die, such as in cases in which the fluidic die ejects fluids in response to current pulses through resistive elements to generate heat), by way of example.
Looking at another illustrative example, in the space of microfluidics, a microfluidic die (e.g., a fluidic die) may be attached to a supporting component made up of a molding compound and having channels. In this case, the channels may be used to direct fluids and solids (e.g., blood, plasma, etc.) towards desired portions of the microfluidic die.
In these and other cases, there may be a desire to reduce device size. For example, smaller biomedical devices may be desirable, such as to enable inclusion of multiple testing apparatuses on a small die. Smaller devices may also enable biomedical testing using smaller fluidic volumes. And smaller devices may also reduce overall cost, such as by enabling a greater number of dies to be produced from a wafer. Of course, there may be a number of other reasons to seek to decrease a size of a fluidic device.
One aspect of the push to reduce fluidic device size may be reducing channel size within molded components. For instance, while it may be possible to use semiconductor fabrication processes to achieve node sizes on the order of 20 nm (and less), achieving corresponding sizes for channels within molded compounds may present complexity and challenges using traditional build-up fabrication and/or machining processes. In fact, even at the range of tens or hundreds of μm, forming channels in molded components may be challenging and/or expensive. For example, it may not be currently possible to machine channels within a molded component on the order of five μm to five hundred μm.
And returning to the example of an inkjet ejection device, there may be a desire to increase a fluid ejection nozzle density. But it may be that fluidic channel sizes within a molded component connected to a fluidic die may limit possible nozzle densities. There may be a desire, for instance, to have fluidic channels within a molded component on the order of five μm to five hundred μm, by way of example.
With the foregoing in mind, the present description proposes a process capable of yielding devices and components having channels on the order of tens to hundreds of μm.
In one implementation, for example, such channel sizes may be achieved by using a sacrificial material on or over which a molding material is deposited. The sacrificial material may then be removed (e.g., etched away) to leave channels of the desired dimensions within the molded structure. Thus, for example, channels on the order of tens to hundreds of μm may be formed within a molded component. In some cases, it may be possible to achieve channels of less than ten μm using a sacrificial material.
In some cases, this approach for creating channels within a molded component may also allow creation of other structures within the molded component. For instance, embedded traces of sacrificial material may be used in addition to thermo-electric traces and both may be encapsulated within a molding compound. The sacrificial material may be removed (e.g., etched away) while leaving the thermo-electric traces (e.g., by protecting the thermo-electric traces using a layer of photoresist while removing the sacrificial material). Thus, the resulting molded device may be suitable for propagation of fluidics (through the channels) and thermal energy and/or electrical signals (through the electrical traces; in some cases, the thermal energy may propagate through channels, as well).
As shall be apparent, such an approach may be desirable for yielding molding components with channels having desired dimensions.
In the context of a biomedical microfluidic device, fluidic die 104 may correspond to a microfluidic die, and molded structure 102 may correspond to a molded support component through which fluids may flow to and/or from the microfluidic die. Similar to the case of the fluidic die for ejection of printing fluids, the molded device in this example may enable operation of the biomedical microfluidic die due in part to the channels (e.g., channels 108) within molded structure 102. It will be appreciated that such fluidic dies may be used in a number of other cases, such as molded devices supporting chips with light emitting diodes (LEDs) and through which electrical signals and/or EMR may propagate; molded devices supporting sensor devices through which electrical signals, gasses and/or liquids may propagate for sensing by the sensor devices, etc.
Molded structure 102 may be composed of materials having a low coefficient of thermal expansion (low CTE). Example materials include (but are not limited to) epoxy molding compounds (EMC) and thermoplastic materials (e.g., polyphenylene sulfide (PPS), polyethylene (PE), polyethylene terephthalate (PET), polysulfones (PSU), liquid-crystal polymer (LCP), etc.). In one implementation, molded structure 102 may comprise a material (such as one of the foregoing) having a low CTE, such as in the range of 20 ppm/C or less. For instance, in one case, a material (such as one of the foregoing) may be selected having a low CTE, such as a CTE of 12 ppm/C or less.
As shall be discussed in further detail hereinafter, the material of molded structure 102 may be applied on or over a structure having sacrificial materials and/or thermo-electric traces. For example, sacrificial materials may be in the form of traces of a desired material (e.g., copper (Cu), nickel (Ni), etc.). In one case, for example, sacrificial structures may be applied to a support structure. In another case, a lead frame structure having portions with sacrificial materials may be used. A molding compound may then be applied on or over the structure.
Molded structure 102 may be unitary in form. As used herein, a unitary structure refers to a component that cannot be broken into parts without breaking an adhesive bond, cutting a material, or otherwise destroying that component. For example, an EMC may be used to form a unitary molded structure 102 having thermo-electric traces 106 and channels 108 formed therein as part of a molding process.
Returning to
As noted, in one implementation, both thermo-electric traces 106 and channels 108 may be embedded within molded structure 102. However, in other cases, channels 108 may be embedded within molded structure 102 while thermo-electric contacts 110 may be in communication with thermo-electric traces external to molded structure 102 (not shown).
Furthermore, as noted above, in some implementations, thermo-electric traces 106 may correspond to electrically and/or thermally conductive traces that may be used for purposes other than carrying signals to thermo-electric contacts 110. For example, traces 106 may be capable of dissipating thermal energy away from fluidic die 104.
Because channels 108 may be formed within molded structure 102 using a sacrificial material that is subsequently removed, channels 108 may be between ten μm and two hundred μm, or less, in one dimension.
With the foregoing in mind, whether molded structure 102 is used in conjunction with a fluidic die for ejecting printing fluid or something else, as noted above, there may be a desire to have channels having a dimension of between ten μm and two hundred μm, or less. Such channel dimensions may be beneficial, such as by allowing apertures 112 of fluidic die 104 to be more densely arranged within fluidic die 104, such as than might otherwise be the case.
Thus, an example device (e.g., device 100) may comprise a molded structure (e.g., molded structure 102) connected to a fluidic die (e.g., fluidic die 104). The molded structure may comprise thermo-electric traces (e.g., thermo-electric traces 106) and channels (e.g., channels 108). The channels are to be between ten μm and two hundred μm, or less, in one dimension. The fluidic die may comprise apertures (e.g., apertures 112) corresponding to the channels and through which fluids, electromagnetic radiation, or a combination thereof is to travel. The fluidic die may also comprise contacts (e.g., electrical contacts 110) corresponding to the thermo-electrical traces of the molded structure. As noted above, the fluidic die may include a fluid ejection die, such as to eject printing fluid via ejection nozzles.
To illustrate with the example of a printing fluid ejection device, printing fluid may be caused to flow toward fluidic die 104 (for ejection onto a substrate) through fluid through holes 152 of fluidic fan-out structure 150, channels 108 of molded structure 102, and through apertures 112 of fluidic die. In some cases, printing fluid may flow away from fluidic die 104 (such as to recirculate the printing fluid to keep colorants of the printing fluid mixed) through apertures 112, channels 108, and back out fluid through holes 152.
Example device 100 may also be used for thermal control and dissipation, as noted above. For instance, fluidic die 104 may comprise a semiconductor device that may generate thermal energy (e.g., heat) through normal operation (e.g., as electrical current travels through traces and components of the semiconductor device). Fluidic die 104 may have microfluidic channels within its structure through which fluid may flow in order to remove thermal energy from the device. The thermal energy dissipating fluid may enter and leave fluidic die 104 via apertures 112. For example, cooling fluid may travel through fluid through holes 152, channels 108, and enter apertures 112. The cooling fluid may extract thermal energy from fluidic die 104 and may carry the extracted thermal energy through apertures 112, channels 108, and fluid through holes 152.
With the foregoing in mind, an example fluidic device (e.g., device 100 in
Turning to
Fluid ejection device 200 of
As should be apparent, fluidic die 204, molded structure 202, and fluidic fan-out structure 250 may be arranged such that a fan-out fluid through hole 252 is in fluid communication with one extremity of channel 208 (e.g., the lower dotted portion of molded fluid feed slot 254), and further that an aperture 212 is in fluid communication with another extremity of channel 208 (e.g., the upper portion of molded fluid feed slot 254 within the oval of aperture 212).
In operation, a fluid, such as a printing fluid, may be transmitted through a fan-out fluid through hole 252 (e.g., the left through hole 252 in
Residual fluids may recirculate through the system by exiting fluidic die 204 through another aperture 212 (e.g., the right aperture 212), another molded fluid feed slot 254 (e.g., the right fluid feed slot 254), and another fluid through hole 252 (e.g., the right through hole 252) and on to other components of the apparatus.
In the next drawings,
As shown in
Fluidic die 304 includes a number of elements that are similar to those already discussed in relation to
Turning, for instance, to
With the foregoing in mind, it should be apparent that in one implementation, an example fluidic ejection device (e.g., device 300) may be such that the fluidic die (e.g., fluidic die 304) comprises ejection chambers (e.g., ejection chamber 315) in fluid communication with fluidic channels (e.g., channels 308) of the molded structure (e.g., molded structure 302) and ejection nozzles (e.g., nozzles 316) of the fluidic die. The fluidic die, the molded structure, and the fluidic fan-out structure (e.g., fluidic fan-out structure 250 of
In another implementation, an example fluidic ejection device (e.g., device 300) may comprise a fluidic die (e.g., fluidic die 304) attached to an epoxy molding compound (EMC) fluidic and electrical chiclet (e.g., molded structure 302). A fluidic circulation path (e.g., fluid circulation path defined by arrow A) defined through microfluidic channels (e.g., channels 308) of the EMC fluidic and electrical chiclet and apertures of the fluidic die. The device may also comprise a thin adhesive compound layer (e.g., adhesive layer 356) between the fluidic die and the EMC fluidic and electrical chiclet. An electrical communication path may also be defined between electrical contacts (thermo-electric contacts 310) of the fluidic die and electrical traces (e.g., thermo-electric traces 306) of the EMC fluidic and electrical chiclet. The microfluidic channels may have a width of between ten μm and fifty μm and a height of between one hundred μm and four hundred μm.
Turning to
Starting with
Channels 408 may be separated by a number of separation structures 414. Channels 408 may be arranged within molded structure 402 to correspond to (e.g., be in fluid communication with) apertures of a fluidic die (e.g., apertures 112 of fluidic die 104).
In some cases, there may be a correspondence between the width of channels 408 (e.g., D1) and a height of channels 408 (e.g., D3, see also,
Another dimension of channels may be a width of separation structures 414, represented as D2. Similar to the dimensions, D1 and D3, the width of separation structures 414 may depend on the context in which molded structure 402 is to be used, the materials used to form molded structure 402, etc. In one example, D2 may comprise between fifty μm and one hundred μm. For instance, in the context of a fluid ejection device, there may be a desire to provide a denser arrangement of fluid ejection nozzles. Thus, achieving a width D2 of approximately ninety μm, may be of interest in one case. In other examples, different dimensions for D2 may be of interest, such as greater or smaller than ninety μm. For example, a different molded structure 402 may have D2 of approximately thirty μm.
Next, D4 represents a channel-to-channel dimension and may be between one hundred μm and five hundred μm in one implementation. Of course, D4 will depend on dimensions D1 and D2. Indeed, in some cases, D4 will be the sum of D1 and D2. Therefore, in an implementation in which D1 is approximately 20 μm and D2 is approximately 90 μm, D4 will be approximately 110 μm.
In the context of an example fluid ejection device, D4 may correspond to a nozzle-to-nozzle spacing. Of course, there may be differences between D4 and nozzle-to-nozzle spacing based, for instance, on nozzle placement with relation to a firing chamber, a particular nozzle architecture (e.g., in some cases, nozzles may be offset with respect to neighboring nozzles), etc. For example, as was described in relation to
D5 is yet another dimension of example molded structure 402 that is shown in both
As should be apparent, the different dimensions of different portions of molded structure 402 may vary according to different needs. However, as already discussed, the process of achieving small dimensions—particularly, D1, D2, and D4—within a molded structure may present challenges and complexities that traditional fabrication and machining approaches may not be able to overcome. Consequently, the approaches and methods described herein—such as using sacrificial traces to be removed from molded structures—may be of interest in a variety of different contexts.
Turning back to
At 505, a molding compound is applied on or over a structure with sacrificial traces. The resulting structure may correspond to a molded package.
Returning to method 500, at 510, a portion of the molding compound is removed.
With sacrificial traces exposed, at 515 of method 500, the sacrificial traces may be removed from within the molding compound. For example, an etching process may be used, such as using a chemical etch to remove the sacrificial traces 622.
Thus, in one implementation, an example method (e.g., method 500) of forming a fluidic device may comprise applying a molding compound (e.g., molding compound 626) on a structure (e.g., structure 624) comprising sacrificial traces (e.g., sacrificial traces 622) to form a molded package. As noted, in some cases, the sacrificial traces may comprise copper (Cu). The method may also comprise removing a portion of the molded package (e.g., portion 628). At times, the removing the portion of the molded package may comprise surface grinding a surface of the molded package. And the method may also comprise removing the sacrificial traces to form embedded fluidic channels (e.g., fluid channels 608) within the molded package. In some implementations, removing the sacrificial traces may comprise etching the Cu-based sacrificial traces.
Moving on to
At 705, a structure comprising sacrificial traces (e.g., sacrificial traces 822 in
At 710, a molding compound (e.g., molding compound 826 in
At 715, a portion of the molding compound is removed. Removal of a portion of the molding compound is not shown in
At 720, photoresist (e.g., photoresist layer 832 in
At 725, a portion of the support layer is etched.
At 730, the sacrificial traces are removed from the molding compound. The photoresist layer 832 may also be removed, leaving a finished molded structure 802, as illustrated in
At 735, a fluidic die (e.g., fluidic die 804) may be attached to the molded package, as illustrated in
At 740, a fluidic fan-out structure (e.g., fluidic fan-out structure 850) may be attached to the molded package, as illustrated in
With the foregoing in mind, another example method may include parts of example methods discussed, above. Additionally, it may include applying a photoresist layer (e.g., photoresist layer 832) on the molded package and leaving a photoresist window in the photoresist layer in relation to the support layer. Subsequently, a portion of the support layer corresponding to the photoresist window may be etched away. The example method may also include attaching a fluidic die (e.g., fluidic die 804 having an example nozzle 816) to a first surface 836b of the molded package using a thin adhesive compound layer such that apertures of the fluidic die correspond to embedded fluidic channels of the molded package. The method may also include attaching a fluidic fan-out structure (e.g., fluidic fan-out structure 850) to a second surface (e.g., surface 836a) of the molded package such that fluidic fan-out through holes (e.g., fan-out fluid through holes) of the fluidic fan-out structure correspond to the embedded fluidic channels of the molded package, and further such that fluid paths are defined through the fan-out fluid through holes, embedded fluidic channels, and apertures.
As noted, in some cases, the example method of applying the molding compound on the structure comprising sacrificial traces may also comprise applying the molding compound on a structure comprising electrical traces. And it may also include applying a photoresist layer to protect the electrical traces while the sacrificial traces are removed.
As should be apparent from the above, the present description provides an approach for forming channels within a molded structure using sacrificial materials, such as to enable recirculation of fluids between a fluidic die and channels of the molded structure.
In the present description, in a particular context of usage, such as a situation in which tangible components (and/or similarly, tangible materials) are being discussed, a distinction exists between being “on” and being “over.” As an example, deposition of a substance “on” a substrate refers to a deposition involving direct physical and tangible contact without an intermediary, such as an intermediary substance (e.g., an intermediary substance formed during an intervening process operation), between the substance deposited and the substrate in this latter example; nonetheless, deposition “over” a substrate, while understood to potentially include deposition “on” a substrate (since being “on” may also accurately be described as being “over”), is understood to include a situation in which intermediaries, such as intermediary substances, are present between the substance deposited and the substrate so that the substance deposited is not necessarily in direct physical and tangible contact with the substrate.
A similar distinction is made in an appropriate particular context of usage, such as in which tangible materials and/or tangible components are discussed, between being “beneath” and being “under.” While “beneath,” in such a particular context of usage, is intended to necessarily imply physical and tangible contact (similar to “on,” as just described), “under” potentially includes a situation in which there is direct physical and tangible contact but does not necessarily imply direct physical and tangible contact, such as if intermediaries, such as intermediary substances, are present. Thus, “on” is understood to mean “immediately over” and “beneath” is understood to mean “immediately under.”
It is likewise appreciated that terms such as “over” and “under” are understood in a similar manner, as previously mentioned. These terms may be used to facilitate discussion but are not intended to necessarily restrict scope of claimed subject matter. For example, the term “over,” as an example, is not meant to suggest that claim scope is limited to situations in which an implementation is right side up, such as in comparison with the implementation being upside down, for example. An example includes a molded structure (e.g., molded structure 202 in
Unless otherwise indicated, in the context of the present disclosure, the term “or” if used to associate a list, such as A. B, or C, is intended to mean A, B, and C, here used in the inclusive sense, as well as A, B, or C, here used in the exclusive sense. With this understanding, “and” is used in the inclusive sense and intended to mean A, B, and C; whereas “and/or” can be used in an abundance of caution to make clear that all of the foregoing meanings are intended, although such usage is not required. Furthermore, the terms “first,” “second” “third,” and the like are used to distinguish different aspects, such as different components, as one example, rather than supplying a numerical limit or suggesting a particular order, unless expressly indicated otherwise. Likewise, the term “based on” and/or similar terms are understood as not necessarily intending to convey an exhaustive list of factors, but to allow for existence of additional factors not necessarily expressly described.
In the preceding description, various aspects of claimed subject matter have been described. For purposes of explanation, specifics, such as amounts, systems and/or configurations, as examples, were set forth. In other instances, well-known features were omitted and/or simplified so as not to obscure claimed subject matter. While certain features have been illustrated and/or described herein, many modifications, substitutions, changes and/or equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all modifications and/or changes as fall within claimed subject matter.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/039078 | 6/25/2019 | WO | 00 |