Molded integrated circuit dies

Abstract

A method includes providing an integrated circuit (IC) die on a carrier, depositing mold material over the IC die to form a molded structure, removing a molded IC die from the carrier, thinning the molded IC die until a thickness of the IC die and a thickness of the molded structure are less than 100 pm, forming one of a fluidic channel or a sensor in the IC die of the molded IC die, and stacking the molded IC die onto a second molded IC die.

Description

MOLDED INTEGRATED CIRCUIT DIESBACKGROUND

[0001] Microfabrication and micromachining processes can refer to processes in which micrometer scale or smaller structures and devices can be formed. For example, microfluidic systems correspond to various microstructures which can be implemented in microfluidic devices. As another example, microfluidic devices, such as fluid ejection devices, can correspond to devices of a micrometer or smaller scale that convey, dispense, and / or process small amounts (e.g., microliters, picoliters, etc.) of fluid substances.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Non-limiting examples of the present disclosure are described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. Unless indicated as representing the background art, the figures represent aspects of the disclosure. For purposes of clarity, not every component can be labeled in every drawing. In the drawings:

[0003] FIG. 1 A and FIG. IB show cross-sectional views of example structures.

[0004] FIG. 2A to FIG. 2B show cross-sectional views of example structures.

[0005] FIG. 3 A to FIG. 3C show cross-sectional views of example structures.

[0006] FIG. 4 shows a flowchart of an example process.

[0007] FIG. 5 shows a flow diagram of an example process.

[0008] FIG. 6 shows a flowchart of an example process.

[0009] FIG. 7 shows a flow diagram of an example process

[0010] FIG. 8 shows a cross-sectional view of an example structure associated with the process of FIG. 4.DETAILED DESCRIPTION

[0011] A microfluidic structure can include a molded structure and an integrated circuit (IC) die (e.g., a fluid ejection die). For example, the microfluidic structure can be a molded IC die, in which the IC die is molded by the molded structure. The IC die can be or include a fluidic device, such as a fluid ejection device, a fluid ejection die, a sensor of a fluid process device, etc., to control fluid contained therein. In some examples, the molded IC die can include fluidic channels and various types of devices to control fluid (e.g., actuators for ejecting, pumping, etc.).

[0012] The performance of the molded IC die can be improved with thinner structures. For example, the thinner the molded IC die, the shorter distance the fluid (e.g., printing fluid, analytes, etc.) flows, thereby enabling faster delivery of the fluid. In such fluidic packages as sensing devices for biomaterial, cells, chemical, etc., the molded IC die with the reduced thickness can facilitate sensing and / or processing of analytes. The reduced thickness allows for room for stacking of multiple IC dies and / or various micro-electro-mechanical systems (MEMS) components. For example, the molded IC die with the reduced thickness can enable three-dimensional stacking of microfluidic structures (e.g., MEMS, a sensor, an applicationspecific IC (ASIC), etc.) to perform various fluidic functions.

[0013] However, achieving the desired thinness presents challenges. Throughout manufacturing and operational phases, IC dies are subjected to high temperatures, exacerbating bowing issues caused by thermal expansion coefficient mismatches between the IC die (e.g., silicon) and surrounding layers (e.g., SU8). This phenomenon becomes particularly acute in thin dies, leading to pronounced bowing that severely impacts the performance of the IC die. Print uniformity suffers in the case of fluid ejection dies, while process uniformity is compromised in fluid process dies. Additionally, the susceptibility of thin IC dies to bowing underscores the complexity of integrating these components into larger systems. Achieving precise alignment becomes a daunting challenge, as even slight deviations can lead to performance degradation. Furthermore, the fragility of thin IC dies complicates handling during manufacturing processes. The structural delicacy of these dies, especially when reduced to a few hundred micrometers in thickness, poses significant challenges. Moreover, while a wafer (e.g., a silicon substrate) is delicate by itself, as the IC die includes various components (e.g., fluidic channels, etc.) which could make the IC die more structurally fragile, manufacturing processes may become even more complicated . Forexample, thinning, which involves an aggressive process, can affect both the components and the structural rigidity of the die. Thinning processes that do not use the thinning techniques disclosed herein can rely on a support carrier and / or a temporary bonding, leading to increased manufacturing costs and complexity, as well as potential deformation of the IC die (e.g., a wafer bowing, etc.). Additionally, such thinning processes often involve the use of a stability-enhancing component (e.g., strengthening pillars), consuming the device area and thus reducing the yield.

[0014] It should be appreciated, therefore, that techniques for an IC die with thin profiles, while maintaining structural rigidity and simplifying manufacturing processes, may be of interest, such as to reduce cost and / or complexity of devices. As should be apparent from the foregoing, the present application proposes molded IC dies (e.g., an IC die molded into a molded structure) with a reduced thickness and methods of forming the same, such as compared with current devices and methods. According to the present application, the thinning of molded IC dies can be achieved without an additional support carrier or a stability-enhancing component. Since the molded IC dies disclosed herein can be thinned without such additional components and / or processes, the thinning process can be achieved cost-effectively with a simpler process. In addition, the molded IC dies disclosed herein can be thinned without (or with a reduced amount of) deformation of the IC die (e.g., a wafer bowing, etc.). In some examples, the thinning process can include flattening a surface of the molded IC die, which can improve processability of the molded IC die. For example, this can facilitate stacking of the molded IC dies.

[0015] An aspect of the present disclosure is directed to thinning an IC die that is molded into a molded structure (e.g., epoxy molding compound). In some examples, the molded IC die (e.g., the IC die that is molded into the molded structure) can be thinned until its thickness is 100 pm. For example, the molded IC die can be ground until the thickness is 35 pm or less. According to the disclosure, the molded IC die with the reduced thickness can be achieved while the IC die can be exposed to fluidics at both sides (e.g., top and bottom surfaces of the molded IC die). This exposure, along with the reduced thickness and lack of deformation (e.g., without the bowing issues), allows for multilayer stacking of molded IC dies. In some examples, a thickness of stacked molded IC dies can be 100 pm or less, while each of the molded IC die can be as thin as 35 pm. The stacking of fluidic IC dies can enable animproved operating frequency (e.g., a faster frequency, a tuned frequency, etc.) while achieving complex fluidic functions, with a low-profile package.

[0016] Reference is now made to the figures. Although the figures and aspects of the disclosure can show or describe structures herein as having a particular shape, it should be understood that such shapes are merely illustrative and should not be considered limiting to the scope of the techniques described herein. For example, the techniques described herein can be implemented in any shape or geometry for any material or layer to achieve desired results.

[0017] FIG. 1 A shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 1 A is an example microfluidic structure 10A that has been thinned through a thinning process 150. In some examples, the microfluidic structure 10A can be referred to as a “molded IC die” (e.g., an IC die 120A molded into a molded structure 110A). As shown, the microfluidic structure 10A can be formed with thin profiles through the thinning process 150, while maintaining structural rigidity. The thinning process 150, including thinning of the IC die 120 A molded in the molded structure 110A, can be performed to thin down the microfluidic structure 10A to a desired thickness (e.g., 100 pm, 35 pm, etc.), with the molded structure 110A serving as a support carrier. As the thinning process 150 does not involve the use of an additional support carrier or a stability-enhancing component, the thinning process 150 can be achieved cost-effectively, such as by way of a simpler process. In addition, the microfluidic structure 10A can be thinned through the thinning process 150 without (or with a reduced amount of) deformation of the IC die 120A (e.g., a wafer bowing, etc.). This can thereby improve the performance of the IC die 120A without sacrificing the die yield or structural stability. It is noted that the description with respect to FIG. 1 A, FIG. IB, FIG. 2A, FIG. 2B, FIG. 3 A, FIG. 3B, and FIG 3C is directed to example structures that can be formed based on a thinning process (e.g., the thinning process 150) of the present disclosure, while the description with respect to FIG. 4 to FIG. 8 is directed to examples of the thinning process. Shown in FIG. 1 A is a non-limiting example of the microfluidic structure 10 A. In some examples, the microfluidic structure 10A can include more, fewer, or different components than shown in or described with respect to FIG. 1 A.

[0018] In some examples, the molded structure 110A can be or include a support for the IC die 120 A. The molded structure 110A can include material for protecting the IC die 120 A. For example, the molded structure 110A can be or include an epoxy molding compound(EMC) to encapsulate the IC die 120 A. The molded structure 110A can be thinned along with the IC die 120A through the thinning process 150.

[0019] In some examples, the IC die 120 A can be of a fluidic device. The IC die 120 A can be or include a fluid ejection device, a fluid process device, a fluid ejection die, a fluid process die, etc. to control fluid contained therein. For example, the IC die 120A can be a fluidic ejection die to eject fluid in a fluidic device, a fluidic processing die to process (e.g., sense) fluid in a fluid process device, etc. In some examples, the IC die 120 A can include a plurality of fluidic channels. In some examples, the IC die 120A can include fluidic ejection / process devices, including but not limited to, a fluidic pump, a valve, a reaction chamber, a sensor, a fluid ejection circuit, a fluid process circuit, etc. In some examples, the IC die 120 A can be molded into the molded structure 110A.

[0020] In some examples, the IC die 120 A can be exposed to fluidics at an exposed surface (e.g., a top surface, a bottom surface, etc.), which can facilitate stacking of the microfluidic structure 10A (and the IC die 120A). For example, the IC die 120A can be fluidically or electrically connected to a second IC die (e.g., as shown in FIG. IB) through the exposed surface. Along with the thin profiles formed through the thinning process 150 and the microfluidic structure 10A with a reduced amount of deformation (e.g., bowing issues), the surface exposure discussed herein enables stacking of multiple IC dies and / or various MEMS components, thereby integrating various fluidic functional devices.

[0021] In some examples, although depicted as including one IC die 120 A, the microfluidic structure 10A can include a plurality of IC dies 120A (e.g., as shown in FIG. 3C). For example, the microfluidic structure 10A can include a first IC die 120 A and a second IC die 120 A. In some examples, the first IC die 120 A and the second IC die 120 A can be arranged in parallel in the microfluidic structure 10 A. In some examples, the first IC die 120 A and the second IC die 120 A can be stacked on each other within the microfluidic structure 10 A. In some examples, the first IC die 120A and the second IC die 120A can be fluidically and / or electrically connected to each other.

[0022] In some examples, the IC die 120A can be or include one of a sensor (e.g., an optical sensor), a fluidic channel, an ASIC, etc. For example, the first IC die 120A can be or include a fluidic device (e.g., a fluid ejection device, a fluid process device, etc.), and the second ICdie 120A can be or include an ASIC. In some examples, the IC die 120A can be or include a sensor to detect a characteristic of fluid associated with the microfluidic structure 10A.

[0023] In some examples, a thickness 102 A of the microfluidic structure 10A can be less than 100 pm. For example, a thickness of the IC die 120A and / or a thickness of the molded structure 110A can be less than 100 pm. In some examples, the thickness 102A of the microfluidic structure 10A can be less than 35 pm. For example, a thickness of the IC die 120A and / or a thickness of the molded structure 110A can be less than 35 pm. As disclosed herein, a “thickness” (e.g., the thickness 102A as shown in FIG. 1 A) of a microfluidic structure (e.g., the microfluidic structure 10A) can refer to a thickness of a molded structure (e.g., the molded structure 110A) and / or a thickness of an IC die (e.g., the IC die 120A). In some examples, the molded structure 110A and the IC die 120 A can form a co-planar surface. The microfluidic structures (or the molded IC dies) disclosed herein with the thin profiles, such as the thickness 102 A, can be formed without or with a reduced amount of deformation (e.g., the bowing issues), as discussed above, while not sacrificing the die yield, structural stability, or manufacturing simplicity. For example, the thinning process 150 can be performed to achieve the thickness 102 A without involving an additional component (e.g., an additional carrier, a stability enhancing-component, etc.).

[0024] With the foregoing in mind, including the thinning process 150 for the microfluidic structure 10A and associated benefits, the figures and description below illustrate various examples of the microfluidic structures and processes of forming the same (e.g., including the thinning process 150). It should be noted that the figures and description below are nonlimiting examples and can be implemented as any of various other configurations while remaining within the scope of the present disclosure.

[0025] FIG. IB shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. IB is an example microfluidic structure 10S. The microfluidic structure 10S includes the microfluidic structure 10A and a microfluidic structure 10B. The microfluidic structure 10B can include a molded structure HOB and an IC die 120B. The microfluidic structure 10B can be substantially similar to and / or incorporate features of the microfluidic structure 10 A. For example, the molded structures 110A, HOB can be thinned through the thinning process 150, and then can be stacked on each other (e.g., as shown in FIG. IB). Shown in FIG. IB is a non-limiting example of the microfluidic structure 10S. Insome examples, the microfluidic structure IOS can include more, fewer, or different components than shown in or described with respect to FIG. IB.

[0026] In some examples, as shown, the microfluidic structure 10A and the microfluidic structure 10B can be stacked on each other. In some examples, the first IC die 120 A in the microfluidic structure 10A and the second IC die 120B in the microfluidic structure 10A can be fluidically and / or electrically connected to each other. In some examples, the first IC die 120 A in the microfluidic structure 10A can include a fluidic channel, and the second IC die 120B in the microfluidic structure 10B can include a sensor to detect a characteristic of fluid provided through the fluidic channel in the first IC die 120A and / or in the microfluidic structure 10 A.

[0027] In some examples, a thickness 102B of the microfluidic structure 10B can be less than 100 pm. For example, a thickness of the IC die 120B and / or a thickness of the molded structure HOB can be less than 100 pm. In some examples, the thickness 102B of the microfluidic structure 10B can be less than 35 pm. For example, a thickness of the IC die 120B and / or a thickness of the molded structure HOB can be less than 35 pm. In some examples, the molded structure 110B and the IC die 120B can form a co-planar surface.

[0028] In some examples, a thickness 102S (a sum of the thickness 102A and the thickness 102B) can be less than 100 pm. For example, one of the thickness 102A or the thickness 102B can be less than 35 pm. In some examples, each of the thickness 102 A and the thickness 102B can be less than 35 pm. In some examples, the molded structure 110A and the IC die 120A can form a co-planar (and / or flat) surface at a surface (e.g., a top surface), and the molded structure 110B and the IC die 120B can form a co-planar (and / or flat) surface at a surface (e.g., a bottom surface). The co-planar (and / or flat) surfaces of the microfluidic structure 10A and the microfluidic structure 10B can facilitate stacking of the microfluidic structure 10A and the microfluidic structure 10B and fluidic and / or electrical connecting of the IC die 120 A and 120B.

[0029] By stacking the thinned microfluidic structures 10 A, 10B, the microfluidic structure 10S can be formed in a way that allows for faster delivery and / or process of the fluid contained therein and various fluidic functions, while also providing the benefits discussed with respect to FIG. 1 A. It should be appreciated, therefore, that microfluidic structures, such as the microfluidic structures 10A, 10B, that are thinned down to a desired thickness and / orinclude stacked layers, may be of interest. The figures and description illustrated with respect to FIG. 3A, FIG. 3B, FIG. 3C, etc. provide various examples of the microfluidic structures. It should be noted that the figures and description below are non-limiting examples and can be implemented as any of various other configurations while remaining within the scope of the present disclosure.

[0030] FIG. 2A shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 2A is an example microfluidic structure 20A. In some examples, the microfluidic structure 20A can be substantially similar to and / or incorporate features of the microfluidic structures 10A, 10S, etc. For example, the microfluidic structure 20A can be a molded IC die (e.g., a fluid ejection device) that has been thinned through a thinning process (e.g., the thinning process 150). The microfluidic structure 20A can include a molded structure 210A and an IC die 220A. Shown in FIG. 2A is a non-limiting example of the microfluidic structure 20A. In some examples, the microfluidic structure 20A can include more, fewer, or different components than shown in or described with respect to FIG. 2A.

[0031] The IC die 220A can include a fluidic device 222A and a fluidic channel 224A. In some examples, the fluidic device 222A can be a fluidic IC circuit, including but not limited to, a fluid ejection device, a fluid process device (e.g., a sensor), etc. For example, the fluidic device 222A can be or include a silicon-based fluidic IC circuit. In some examples, the fluidic channel 224A can be a fluidic channel network that is fluidically connected to the fluidic device 222A. The fluidic channel 224A can receive fluid from the fluidic device 222A and / or provide fluid to the fluidic device 222A. For example, the fluidic channel 224A can be or include an SU8-based microfluidic channel.

[0032] In some examples, as shown in FIG. 2A, the microfluidic structure 20A can be exposed to fluidics both at a top surface and a bottom surface. For example, the microfluidic structure 20A can be fluidically connected to a second microfluidic structure at the top surface of the microfluidic structure 20A and connected to a third microfluidic structure at the bottom surface of the microfluidic structure 20A. In some examples, the microfluidic structure 20A can be directly attached to a chiplet or a pen body for fluidic fan-out.

[0033] In some examples, a thickness 202 A of the fluidic device 222 A can be less than 100 pm. For example, the thickness 202A can be 35 pm or less. In some examples, a thickness 203 A of the fluidic channel 224A can be less than 35 pm. In some examples, a thickness ofthe microfluidic structure 20A can be less than 100 pm. The microfluidic structure 20A can be thinned to a thickness (e.g., a sum of the thickness 202A and the thickness 203 A) through the thinning process disclosed herein (e.g., the thinning process 150), thereby forming a molded IC die with thin profiles while maintaining structural stability. As shown, the IC die may include various components (e.g., fluidic channels, etc.) which could make the IC die structurally fragile. The thinning process of the microfluidic structure 20A with the molded structure 210A serving as a support for the fluidic device 222 A allows the microfluidic structure 20A to be thinned while maintaining structural rigidity and avoiding structural deformation (e.g., the bowing of the fluidic device 222A).

[0034] FIG. 2B shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 2B is an example microfluidic structure 20B. In some examples, the microfluidic structure 20B can be substantially similar to and / or incorporate features of the microfluidic structures 10A, 10S, etc. For example, the microfluidic structure 20B can be a molded IC die (e.g., a fluid process device) that has been thinned through a thinning process (e.g., the thinning process 150). The microfluidic structure 20B can include a molded structure 210B and an IC die 220B. Shown in FIG. 2B is a non-limiting example of the microfluidic structure 20B. In some examples, the microfluidic structure 20B can include more, fewer, or different components than shown in or described with respect to FIG. 2B.

[0035] In some examples, the microfluidic structure 20B can include a microchannel structure 212B, which includes a fluidic channel 222B. For example, the fluidic channel 222B can be a fluidic channel embedded within the microchannel structure 212B. In some examples, the microfluidic structure 20B can be a stacked structure of the microchannel structure 212B and the molded structure 210B.

[0036] The microchannel structure 212B can be fluidically connected to the molded structure 210B and / or the IC die 220B. In some examples, the fluidic channel 222B of the microchannel structure 212B can be fluidically connected to a fluidic channel of the molded structure 210B. For example, as shown, fluid can enter through a fluidic channel 215B of the molded structure 210B, flow through the fluidic channel 222B, and exits the microfluidic structure 20B through a fluidic channel 216B of the molded structure 210B.

[0037] The IC die 220B can be or include a fluidic IC circuit, including but not limited to, a fluid ejection device, a fluid process device (e.g., a sensor), etc. For example, the IC die 220Bcan be a sensor to detect a characteristic of fluid (e.g., a biomaterial, a cell, a chemical, etc.). In some examples, the fluidic channel 222B of the microchannel structure 212B can be fluidically connected to the IC die 220B. For example, the IC die 220B can include a sensing surface fluidically connected to the fluidic channel 222B, and the IC die 220B can detect or sense a characteristic of fluid passing through the sensing surface and / or the fluidic channel 222B.

[0038] In some examples, a thickness of the IC die 220B can be less than 100 pm. For example, the thickness of the IC die 220B can be 35 pm or less. In some examples, a thickness 202B of the microfluidic structure 20B can be less than 100 pm. The microfluidic structure 20B can be thinned to a thickness (e.g., the thickness 202B) through the thinning process disclosed herein (e.g., the thinning process 150). While providing the benefits discussed above, the microfluidic structure 20B with the thin profiles can achieve improved performance, for example, by providing a shorter distance that the fluid flows, thereby enabling faster delivery and / or process of the fluid.

[0039] As discussed above, the reduced thickness of the molded IC die allows for room for stacking of multiple IC dies, which in turn enables integrating various fluidic functions. The description below, with respect to FIG. 3 A, FIG. 3B, and FIG. 3C, illustrate various examples of the stacked microfluidic structures. It should be noted that the figures and description below are non-limiting examples and can be implemented as any of various other configurations while remaining within the scope of the present disclosure.

[0040] FIG. 3A shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 3A is an example microfluidic structure 30A mounted on a printed circuit board (PCB) 330A. In some examples, the microfluidic structure 30A can be substantially similar to and / or incorporate features of the microfluidic structures 10A, 10S, etc. For example, the microfluidic structure 30A can include a first microfluidic structure 31 A and a second microfluidic structure 32A, each of which can be a molded IC die that is thinned through the thinning process disclosed herein. In some examples, a thickness 302A of the microfluidic structure 30A can be less than 100 pm. For example, a thickness of the microfluidic structure 32A can be 35 pm or less, and a thickness of the microfluidic structure 31 A can be 35 pm or less. Shown in FIG. 3 A is a non-limiting example of the microfluidic structure 30A. In some examples, the microfluidic structure 30A can include more, fewer, or different components than shown in or described with respect to FIG. 3 A.

[0041] In some examples, the microfluidic structure 31A and the microfluidic structure 32A can be electrically connected to each other. In some examples, the microfluidic structure 30A can include a trace 311 A. The trace 311 A can electrically connect the microfluidic structure 31A and the microfluidic structure 32A. In some examples, the microfluidic structure 30A can include a trace 312 A. The trace 312A can electrically connect the microfluidic structure 31 A and the PCB 330A. Although not depicted, the microfluidic structure 30A can include a trace that electrically connects the microfluidic structure 32A and the PCB 330A. In some examples, the microfluidic structure 31 A and the microfluidic structure 32A can be fluidically connected to each other. The microfluidic structure 30 A, for example, each of the microfluidic structure 31A and the microfluidic structure 32A, can be controlled (e.g., for fluidic control) through the traces 311 A, 312 A, etc.

[0042] FIG. 3B shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 3B is an example microfluidic structure 30B mounted on a PCB 330B. In some examples, the microfluidic structure 30B can be substantially similar to and / or incorporate features of the microfluidic structure 30A, etc. For example, the microfluidic structure 30B can include a first microfluidic structure 3 IB and a second microfluidic structure 32B, each of which can be a molded IC die that is thinned through the thinning process disclosed herein. In some examples, a thickness 302B of the microfluidic structure 30B can be less than 100 pm. For example, a thickness of the microfluidic structure 32B can be 35 pm or less, and a thickness of the microfluidic structure 3 IB can be 35 pm or less. Shown in FIG. 3B is a non-limiting example of the microfluidic structure 30B. In some examples, the microfluidic structure 30B can include more, fewer, or different components than shown in or described with respect to FIG. 3B.

[0043] As opposed to the microfluidic structure 32A of the microfluidic structure 30A, the microfluidic structure 30B can alternatively include an optical sensor 340B in the microfluidic structure 32B. The optical sensor 340B can detect a characteristic of fluid provided through the fluidic channel in the microfluidic structure 3 IB. Although depicted with the microfluidic structure 32B stacked on the microfluidic structure 3 IB, in some examples, the microfluidic structure 3 IB can be stacked on the microfluidic structure 32B, and the optical sensor 340B of the microfluidic structure 32B can detect fluid in the microfluidic structure 3 IB.

[0044] FIG. 3C shows a cross-sectional view of an example structure. More specifically, the structure shown in FIG. 3C is an example microfluidic structure 30C mounted on a PCB 330C. In some examples, the microfluidic structure 30C can be substantially similar to and / or incorporate features of the microfluidic structures 10A, 10S, etc. For example, the microfluidic structure 30C can be or include a molded IC die that is thinned through the thinning process disclosed herein. In some examples, a thickness 302C of the microfluidic structure 30C can be less than 100 pm. For example, the thickness 302C can be 35 pm or less. Shown in FIG. 3C is a non-limiting example of the microfluidic structure 30C. In some examples, the microfluidic structure 30C can include more, fewer, or different components than shown in or described with respect to FIG. 3C.

[0045] In some examples, the microfluidic structure 30C can include a plurality of IC dies including different types. In some examples, the microfluidic structure 30C can include a fluidic die (e.g., the IC die in FIG. 2A, FIG. 2B, FIG. 3A, FIG. 3B, etc.) and an ASIC. For example, as shown, the microfluidic structure 30C can include a first fluidic IC die 31C, a second fluidic IC die 32C, and an ASIC die 33C. By incorporating different types of IC dies, the microfluidic structure 30C can be integrated with multiple ICs and / or fluidic components, such as ASICs, fluid ejection devices (e.g., thermal inkjet (TH) dies, piezo inkjet (PIJ) dies, etc.), optical sensor, light emitting diodes (LEDs), cell / chemical sensing dies, etc. to achieve different fluidic functions. In some examples, a thickness 302C of the microfluidic structure 30C can be less than 35 pm. In some examples, the microfluidic structure 30C can be mounted on the PCB 330C through a layer of traces. For example, the microfluidic structure 30C can be mounted on the PCB 330C through a redistributed layer (RDL) and / or a ball grid array (BGA).

[0046] In the description below with respect to FIG. 4 to FIG. 8, example methods of forming a molded IC die based on the thinning process (e.g., the thinning process 150) are discussed. The methods of forming molded IC dies, as discussed herein, can achieve the molded IC dies (e g., as shown in FIG. 1 A, FIG. IB, FIG. 2A, FIG. 2B, FIG. 3A, FIG. 3B, FIG. 3C, etc.) with thin profiles (e.g., a reduced thickness such as compared with current devices and methods), without an additional support carrier or a stability-enhancing component, allowing for cost-effective and simpler processes. Moreover, the thinning processes of the methods can be performed without (or with a reduced amount of) deformation of the IC die (e.g., a wafer bowing, etc.). In some examples, the thinning process can include flattening a surface of themolded IC die, which can improve processability of the molded IC die while facilitating stacking of the molded IC dies.

[0047] FIG. 4 shows a flow chart of an example process 40. FIG. 5 shows a flow diagram of an example process (e.g., the process 40). The process 40 can be associated with an example structure at various fabrication stages shown in FIG. 5. It is noted that the process 40 and the flow diagram of FIG. 5 are non-limiting examples. Accordingly, it should be understood that additional operations and / or flows can be provided before, during, or after any of the process 40 of FIG. 4, and / or any of the flow diagram of FIG. 5, that any of the process 40 of FIG. 4, and / or any of the flow diagram of FIG. 5 can be omitted, and that some other operations or flow diagrams can be briefly described herein.

[0048] In a brief overview, the process 40 can start with operation 410 of providing an integrated circuit (IC) die on a carrier. The process 40 can continue to operation 420 of depositing mold material over the IC die to form a molded structure. The process 40 can continue to operation 430 of thinning the molded IC die. The process 40 can continue to operation 440 of forming one of a fluidic channel or a sensor in the IC die of the molded IC die. The process 40 can continue to operation 450 of stacking the molded IC die onto a second molded IC die.

[0049] At operation 410 of FIG. 4, a structure 51 of FIG. 5 is formed, in which an IC die 520 is provided on a carrier 580. In some examples, the IC die 520 can be provided on the carrier 580 by pick and placement. In some examples, as shown, a plurality of IC dies 520 can be provided on the carrier 580. In some examples, a plurality of IC dies 520 including different types of fluidic devices (e.g., a fluidic channel, a fluid ejection device, a fluid process device, an ASIC, a sensor, etc.) can be provided on the carrier 580.

[0050] In some examples, the carrier 580 can be a substrate, a frame, or any platform onto which the IC die 520 can be attached (e.g., by pick and placement). For example, the carrier 580 can be or include a wafer level packaging, a panel level packaging, etc. In some examples, the carrier 580 can include a temporary film 581 onto which the IC die 520 can be attached. The temporary film 581 can be or include a double-side tape, a thermal release film, an ultra-violet film, a light to heat conversion adhesive (LTHC), etc.

[0051] At operation 420 of FIG. 4, a structure 52 of FIG. 5 is formed, in which mold material is deposited over the IC die 520 to form a molded structure 510. The molded structure 510can be formed by overmolding or encapsulating the IC die 520. After forming the molded structure 510 at operation 420, a structure 53 of FIG. 5 can be removed from the carrier 580. In some examples, the structure 53 of FIG. 5 can be released from the temporary film 581 of the carrier 580. The structure 53 can be referred to as a “molded IC die” 530.

[0052] At operation 430 of FIG. 4, a structure 54 of FIG. 5 is formed, in which the molded IC die 530 is thinned. That is, the IC die 520 can be thinned with the molded structure 510 serving as a support, which provide additional structural rigidity and stability, thereby allowing for thin profiles (e.g., a reduced thickness such as compared with current devices and methods). In addition, as discussed above, the thinning process discussed herein can prevent the deformation of the IC die 520 so as to improve the performance of the IC die 520 without sacrificing the die area or yield. In some examples, the molded IC die 530 can be thinned until a thickness of the IC die 520 and / or a thickness of the molded structure 510 are less than 100 pm. For example, the molded IC die 530 can be thinned down until a thickness of the IC die 520 and a thickness of the molded structure 510 are less than 35 pm.

[0053] In some examples, the molded IC die 530 can be ground until the thickness of the IC die 520 and / or the thickness of the molded structure 510 are less than 100 pm. For example, the molded IC die 530 can be ground until the thickness of the IC die 520 and / or the thickness of the molded structure 510 are less than 35 pm. In some examples, a bottom surface of the structure 53 can be thinned or ground to reduce the thickness of the molded IC die 530. In some examples, both the top surface and the bottom surface of the structure 53 can be thinned or ground. In some examples, the molded IC die 530 can be thinned with the molded structure 510 serving as a support, which allows for processing of the molded IC die 530 without additional carriers to reduce the thickness. In some examples, the molded IC die 530 can be thinned without an additional component (e.g., an additional carrier as discussed above, a stability enhancing component, etc.). In some examples, at operation 430, the molded IC die 530 can be ground. In some examples, a top surface, a bottom surface, or both of the molded IC die 530 can be ground. In some examples, the grinding can be limited to one side (e.g., the bottom surface). The thinning and / or grinding of the molded IC die 530 can be or include mechanical grinding, chemical mechanical planarization (CMP), etc. In some examples, the thinning and / or grinding can include multiple processes. For example, a coarse grinding can be performed, followed by a fine grinding process and a polishing (e.g., polygrind) process. Although such a thinning process as grinding can involve aggressiveprocesses and the IC die 520 may have fragile structures (e.g., fluidic channels), by thinning the molded IC dies (e.g., the IC die 520 with the molded structure 510 serving as a support), the IC die 520 can be thinned to a desired thickness (e.g., a reduced thickness such as compared with current devices and methods).

[0054] In some examples, at operation 430, a surface manipulation can be performed. For example, a dry etch, a wet etch, a laser drilling, polishing, etc. can be performed on the molded IC die 530 after and / or before the thinning of the molded IC die 530. In some examples, at operation 420, the molded IC die 530 can be flattened or planarized. In some examples, the thinning and / or grinding, including the CMP, can be performed until a predetermined uniformity (e.g., 1 nm roughness, etc.) is achieved.

[0055] At operation 440 of FIG. 4, a structure 55 of FIG. 5 is formed, in which a fluidic device 540 (e.g., a fluidic channel, a fluid ejection device, a fluid process device, a sensor, etc.) can be formed in the IC die 520 of the molded IC die 530. In some examples, any of fluidic devices, such as a fluidic pump, a valve, a reaction chamber, a sensor, a fluid ejection circuit, a fluid process circuit, MEMS, etc., can be formed in the IC die 520. In some examples, various techniques can be used to form the fluidic device. For example, a fabrication process to form the fluidic device can be performed, including but not limited to, etching, lithography, depositing, etc.

[0056] At operation 450 of FIG. 4, a structure 56A of FIG. 5 is formed, in which the molded IC die 530 is stacked onto another molded IC die 532. As the thinning process disclosed herein allows for a reduced thickness, such as compared with current devices and methods, while providing flexible processability (e.g., by flattening the surface) as well as maintaining structural stability, multiple dies (e.g., the molded IC die 530 and the molded IC die 532) can be stacked with maintaining thin profiles and improved alignment between the multiple dies.

[0057] In some examples, referring to a structure 56B, prior to stacking the molded IC die 530, the molded IC die 530 can be cut such that each of the IC dies 520 in the molded IC die 530 can be separately processed (e.g., stacked on different dies or different portions of a die). In some examples, referring to the structure 56A, after stacking the molded IC die 530, the molded IC die 530 and the molded IC die 532 can be connected fluidically or electrically. For example, fluidic channels of the molded IC die 530 and the molded IC die 532 can beconnected. For example, the molded IC die 530 and the molded IC die 532 can be electrically connected through a trace (e.g., the trace 311 A).

[0058] The process 40 of FIG. 4 can be modified in various manners, for example, by incorporating different operations and / or by performing the operations in different orders. In the description below, with respect to FIG. 6 to FIG. 8, non-limiting example variations of the process 40 is discussed. FIG. 6 shows a flow chart of an example process 60. FIG. 7 shows a flow diagram of an example process (e.g., the process 60). The process 60 can be associated with an example structure at various fabrication stages shown in FIG. 7. It should be understood that additional operations and / or flows can be provided before, during, or after any of the process 60 of FIG. 6, and / or any of the flow diagram of FIG. 7, that any of the process 60 of FIG. 6, and / or any of the flow diagram of FIG. 7 can be omitted, and that some other operations or flow diagrams can be briefly described herein.

[0059] Referring to FIG. 6, operation 610 and operation 620 can be performed along with the process 40 of FIG. 4. In some examples, operation 610 can be performed prior to operation 420. At operation 610, a structure 71 of FIG. 7 is formed, in which a temporary structure 710 is formed in the IC die 520, prior to forming the molded structure 510. The temporary structure 710 can be associated with a fluidic device (e.g., a fluidic channel, a fluid ejection device, a fluid process device, a sensor, etc.) to be formed in the IC die 520. In some examples, the temporary structure 710 can be formed within the IC die 520, after the IC die 520 is provided onto the carrier 580. In some examples, the temporary structure 710 can be formed within the IC die 520, before the IC die 520 is provided onto the carrier 580. That is, the IC die 520 including the temporary structure 710 can be provided onto the carrier 580 (e.g., prior to operation 410).

[0060] Referring to FIG. 7, structures 72, 73, 74, 75, 76A, and 76B can be formed similar to the corresponding structures discussed with respect to FIG. 4 and FIG. 5. In some examples, operation 620 can be performed after operation 430. At operation 620, the structure 75 of FIG. 7 is formed, in which the temporary structure 710 is removed, after thinning the molded IC die 530. In some examples, the temporary structure 710 can be removed by selectively etching the temporary structure 710. For example, at operation 620, a wet etching can be performed to selectively strip the temporary structure 710 without affecting the IC die 520 or the molded IC die 530. In some examples, after removing the temporary structure 710, a fluidic device (e.g., a fluidic channel, a fluid ejection device, a fluid process device, a sensor,etc.) can be formed in a space left by the temporary structure 710. In some examples, an additional process (e.g., etching, lithography, depositing, etc.) can be performed to form the fluidic device.

[0061] In some examples, the thinning process disclosed herein can include flattening a surface of the molded IC die, as shown in FIG. 8. FIG. 8 shows a cross-sectional view of an example structure associated with the process 40 of FIG. 4. In some examples, shown in FIG. 8 is the structure 53 of FIG. 5 and can be associated with operation 420 of FIG. 4. In some examples, at operation 420, the structure 53 can be flattened or planarized. As shown in FIG. 8, the structure 53 can include a protruding portion 810, which can be removed by thinning, flattening, grinding, planarizing, or otherwise forming a co-planar surface 820. For example, at operation 420, the thinning of the structure 53 can be performed selectively on the protruding portion 810. Once the co-planar surface 820 is formed, the thinning of the structure 53 can continue on the co-planar surface 820. By forming the co-planar surface 820 (or otherwise flattened surfaces), the molded IC dies can be stacked on each other with improved alignment, leading to improved performance of the various fluidic functions of the stacked IC dies.

[0062] It should be understood that examples described herein should be considered in a descriptive sense and not for purposes of limitation. Descriptions of features or aspects within each example should be considered as available for other similar features or aspects in other examples. While examples have been described with reference to the figures, it should be understood that various changes in form and details can be made therein without departing from the spirit and scope as defined by the following claims.

[0063] The preceding description has been presented to illustrate and describe examples of the principles described. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in light of the description. Therefore, the foregoing examples provided in the figures and described herein should not be construed as limiting of the scope of the disclosure, which is defined in the Claims.

[0064] The disclosure has been described above with reference to the various examples.However, it is to be understood by those of ordinary skill in the art that various modificationscan be made in form and detail without departing from the scope of the disclosure as defined by the appended claims and their equivalents.

[0065] Conditional language used herein, such as, among others, "can," "could," "might," "may," “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain examples include, while other examples do not include, certain features, elements, etc. Thus, such conditional language is not generally intended to imply that an example include logic for deciding, with or without other input or prompting, whether these features, elements, etc. are included or are to be performed in any particular example. The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list.

[0066] While the above detailed description has shown, described, and pointed out novel features as applied to various examples, it can be understood that various omissions, substitutions, and changes in the form and details of the structures or processes illustrated can be made without departing from the spirit of the disclosure. As can be recognized, certain examples described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.

[0067] The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components.

[0068] With respect to the use of substantially any plural and / or singular terms herein, those having skill in the art can translate from the plural to the singular and / or from the singular tothe plural as is appropriate to the context and / or application. The various singular / plural permutations can be expressly set forth herein for sake of clarity.

[0069] It should be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "includes" should be interpreted as "includes but is not limited to," etc.). It should be understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent should be explicitly recited in the claim, and in the absence of such recitation no such intent is present. In those instances where a convention analogous to "one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In those instances, where a convention analogous to "one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It should be understood by those within the art that virtually any disjunctive word and / or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" should be understood to include the possibilities of "A" or "B" or "A and B." Unless otherwise noted, the use of the words “approximate,” “about,” “around,” “substantially,” etc., mean plus or minus ten percent.

Claims

WHAT IS CLAIMED:

1. A method, comprising: providing an integrated circuit (IC) die on a carrier; depositing mold material over the IC die to form a molded structure; removing a molded IC die from the carrier; thinning the molded IC die until a thickness of the IC die and a thickness of the molded structure are less than 100 pm; forming one of a fluidic channel or a sensor in the IC die of the molded IC die; and stacking the molded IC die onto a second molded IC die.

2. The method of claim 1, comprising: prior to depositing the mold material, forming a temporary structure associated with the one of the fluidic channel or the sensor.

3. The method of claim 1, comprising: connecting the molded IC die and the second molded IC die fluidically or electrically.

4. The method of claim 1, wherein the thinning of the molded IC die includes flattening the molded IC die.

5. The method of claim 1, comprising: thinning the molded IC die until the thickness of the IC die is less than 35 pm.

6. A method, comprising: providing an integrated circuit (IC) die on a carrier; depositing mold material over the IC die to form a molded structure; grinding a molded IC die until a thickness of the IC die is less than 100 pm; forming one of a fluidic channel or a sensor in the IC die of the molded IC die; and stacking the molded IC die onto a second molded IC die.

7. The method of claim 6, comprising:grinding the molded IC die until the thickness of the IC die and a thickness of the molded structure are less than 100 gm.

8. The method of claim 6, comprising: prior to grinding the molded IC die, removing the molded IC die from the carrier.

9. The method of claim 6, wherein one of the thickness of the IC die or a thickness of the second molded IC die is less than 35 pm.

10. A structure, comprising: a first molded IC die including a first integrated circuit (IC) die and a first molded structure, the first IC die including a fluidic channel; and a second molded IC die including a second IC die and a second molded structure, the second IC die including one of a fluidic channel or a sensor, wherein the second molded IC die and the first molded IC die are stacked on each other, and wherein a sum of a first thickness of the first molded IC die and a second thickness of the second molded IC die is less than 100 pm.

11. The structure of claim 10, wherein one of the first thickness or the second thickness is less than 35 pm.

12. The structure of claim 10, the first IC die and the second IC die are connected fluidically or electrically.

13. The structure of claim 10, wherein one of the first molded IC die or the second molded IC die includes a plurality of IC dies.

14. The structure of claim 10, wherein the second IC die includes a sensor to detect a characteristic of fluid provided through the fluidic channel in the first molded IC die.

15. The structure of claim 10, wherein the first molded structure and the first IC die form a co-planar surface.

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