Negative rounding for attaching an integrated component to a support

Abstract

Electronic module (1), comprising: a package substrate (3) arranged on a support structure, in particular a stiffening element (104); an integrated component die (2) having a top (5), a bottom (6) and an outer edge (7), wherein the bottom (6) has a first part and a recess (20) at or near the outer edge (7), wherein the integrated component die (2) is laterally at least as wide as the support structure; and a fastening compound (4) comprising a first part (4a) arranged between the first part of the integrated component die (2) and the package substrate (3) and a second part (4b) arranged along at least a part (9) of the recess (20) of the integrated component die (2), wherein the fastening compound (4) is laterally recessed with respect to the outer edge (7) of the integrated component die (2).

Description

BACKGROUND area

[0001] The present disclosure relates generally to methods and structures for attaching an integrated device die to a carrier, and more particularly to methods and structures that can constrain an attachment compound (e.g., underfill, die attach adhesive, etc.) to remain beneath the die. Description of related technology

[0002] Integrated device dies can be attached to a carrier, such as a package substrate, another integrated device die, an interposer, etc., using compounds that are typically deposited in liquid form between the die and the carrier and then cured or hardened. In some integrated device packages, the integrated device die can be flip-chip mounted to the carrier, for example, by solder balls connecting contact pads of a lower surface of the integrated device die to corresponding contact pads of the carrier. An underfill epoxy can be provided around the solder balls between the integrated device die and the carrier.In other examples, an adhesive is provided between the die and the carrier, such as an anisotropic conductive film (ACF) on the backside of the die or conventional die attach adhesives on the frontside or active side of the die. Often, the compound (e.g., the adhesive or underfill epoxy) can extend past the lateral side edges of the integrated device die, which can be undesirable in certain applications, for example, in arrangements where the die is to be placed in close proximity to another device or die is to be laterally spaced. Accordingly, there continues to be a need for improved techniques for attaching an integrated device die to a carrier with an adhesive.

[0003] US 2017 / 0186 719 A1 relates to a semiconductor device comprising a first substrate, a second substrate, a connecting portion, and resin. The second substrate faces the first substrate and has a recess at a position corresponding to an edge portion of the first substrate. The connecting portion is arranged between the first substrate and the second substrate and electrically connects the first substrate and the second substrate. Resin is arranged to remain between the first substrate and the second substrate and cover the connecting portion. A portion of the resin is located in the recess of the second substrate. The recess serves as a resin reservoir for the resin that is caused to flow during bonding and prevents the resin from flowing along a side surface of the first substrate to the back side thereof, thereby preventing contamination by the resin.

[0004] US 2014 / 0159226 A1 relates to a compact sensor module. The sensor module may comprise a stiffener and a sensor substrate having a mounting segment and a first wing segment extending from the mounting segment. The first wing segment may be folded around an edge of the stiffener. A sensor chip may be mounted on the mounting segment of the sensor substrate. A processor substrate may be connected to the sensor substrate. A processor substrate may be mounted on the processor substrate and in electrical connection with the sensor chip. US 2005 / 0051885 A1 relates to a semiconductor package structure including a semiconductor device, a substrate, solder pads, an underfill, a buffer agent, and solder balls. The substrate is located beneath the semiconductor device. A bonding region is formed between the first surface of the semiconductor and the top surface of the substrate.Several solder balls are arranged in the bonding area to electrically connect the semiconductor component and the substrate. Underfill is filled into the bonding area to coat the solder pads and tightly bond the semiconductor component and the substrate. The buffering agent is located in the bonding area to buffer the underfill, which is to be enclosed in the bonding area. Several solder balls are located on the underside of the substrate.

[0005] One resulting problem may be to at least partially overcome the disadvantages arising from the prior art. This problem is solved by the independent patent claims. Advantageous embodiments emerge from the subclaims and the figures. SUMMARY

[0006] In one aspect, an electronic module is disclosed. The electronic module comprises the features of claim 1.

[0007] In one aspect, an electronic module is disclosed. The electronic module comprises the features of claim 10.

[0008] A method for assembling an electronic module is disclosed. The method may include attaching an integrated device to a carrier with a mounting compound. The integrated device die may have a top surface, a bottom surface, and an outside edge. The integrated device die may have a first surface recessed from the bottom surface and a second surface extending between the bottom surface and the first surface, the second surface being laterally recessed from the outside edge. The mounting compound may include a first portion disposed between the bottom surface of the integrated device die and the carrier and a second portion disposed along at least a portion of the second surface of the integrated device die.

[0009] In one aspect, an electronic module is disclosed. The electronic module has the features of claim 18.

[0010] In one embodiment, the electronic module further comprises a plurality of electrical connection conductors that electrically connect first contact pads on the first portion of the integrated component die to corresponding second contact pads on the package substrate. The mounting compound comprises an underfill material disposed around the plurality of electrical connection conductors.

[0011] In one embodiment, the electronic module further comprises active circuitry at or near the bottom of the integrated device die.

[0012] In one embodiment, the electronic module further comprises active circuitry at or near the top of the integrated device die.

[0013] According to the invention, the fixing compound is laterally embedded with respect to the outer edge of the integrated component die.

[0014] In one embodiment, the fastening compound has a concave surface.

[0015] In one embodiment, the package substrate comprises a flexible substrate comprising a non-conductive material with embedded metal traces. The electronic module may further comprise a stiffening element. The flexible substrate may be wrapped around a portion of the stiffening element.

[0016] In one embodiment, the integrated device die comprises a sensor die.

[0017] In one embodiment, the recess is recessed laterally from the outer side edge in a range of 100 micrometers to 500 micrometers.

[0018] In one embodiment, the recess has an inclined wall extending between the first part and the outer side edge.

[0019] In one embodiment, the recess comprises a groove having a first wall extending vertically from the first part to the upper surface and a second wall. The first and second walls are arranged on opposite sides of the groove.

[0020] In one aspect, an electronic module is disclosed. The electronic module includes a package substrate and an integrated device die. The integrated device die has a top surface, a bottom surface, and an outside edge. The bottom surface includes a mounting surface and a groove recessed by the outside edge. The electronic module further includes a mounting compound disposed between the mounting surface of the integrated device die and the package substrate.

[0021] In one embodiment, a portion of the mounting compound is disposed in the groove of the integrated component die.

[0022] In one embodiment, the integrated component comprises a first portion having a first average thickness, a second portion having a second average thickness thinner than the first average thickness, and a third portion depending from the second portion. The groove is formed between the first portion and the third portion.

[0023] In one embodiment, the groove partially surrounds the mounting surface of the lower surface.

[0024] In one embodiment, the electronic module further comprises a lead wire electrically connecting a first contact pad on the top surface of the integrated device die to a second contact pad on the package substrate.

[0025] In one embodiment, the electronic module further comprises a plurality of solder balls that electrically connect first contact pads on the bottom surface of the integrated component die to corresponding second contact pads on the package substrate. The mounting compound comprises an underfill material disposed around the plurality of solder balls.

[0026] In one embodiment, the electronic module further comprises active circuitry at or near the bottom surface of the integrated device die.

[0027] In one embodiment, the mounting compound is laterally recessed with respect to the outer edge of the integrated component die.

[0028] In one aspect, a method of assembling an electronic module is disclosed. The method comprises attaching an integrated device to a carrier with a mounting compound. The integrated device die has a top surface, a bottom surface, and an outside edge. The integrated device die has a first surface recessed from the bottom surface and a second surface extending between the bottom surface and the first surface. The second surface is laterally recessed from the outside edge. The outside edge defines an outermost edge of the electronic module. The method further comprises the mounting compound having a first portion disposed between the bottom surface of the integrated device die and the carrier and a second portion disposed along at least a portion of the second surface of the integrated device die.

[0029] In one embodiment, the carrier comprises a flexible substrate. The method further comprises attaching the flexible substrate to a stiffening element after securing and wrapping the flexible substrate around a portion of the stiffening element.

[0030] In one embodiment, the method further comprises partially sawing through a backside of a wafer to define the first and second surfaces.

[0031] In one embodiment, the attachment compound comprises an underfill epoxy. The method may further comprise electrically connecting first contact pads on the bottom surface of the integrated device die to corresponding second contact pads on the carrier using a plurality of solder balls. The method may further comprise providing the underfill epoxy around the plurality of solder balls.

[0032] In one aspect, an electronic module is disclosed comprising: The electronic module comprises means for attaching an integrated device die to a package substrate. The integrated device die has a top surface, a bottom surface, and an outside edge. The bottom surface has a first portion and means for receiving the means for attaching at or near the outside edge. The integrated device die is laterally at least as wide as the package substrate. The means for attaching comprises a first portion disposed between the first portion of the integrated device die and the package substrate, and a second portion disposed along at least a portion of the means for receiving the means for attaching.

[0033] In one embodiment, the securing means comprises an underfill material, and the means for receiving the securing means comprises a recess. The recess prevents the securing means from moving toward the top surface of the integrated device die.

[0034] Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative dimensions of the following figures may not be to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Specific implementations of the invention will now be described with reference to the following drawings, which are provided by way of example and not by way of limitation. Fig. 1A is a schematic side view of an electronic module including an integrated device die attached to a carrier, according to various embodiments. Fig. Figure 1B is an enlarged schematic side view of an end portion of the electronic module of Fig. 1A. Fig. 1C is an enlarged schematic side view of an end portion of an electronic module according to another embodiment. Fig. Figure 1D is a schematic side view of an electronic module, with the integrated device die wire-bonded to the carrier by bond wires. Fig. Figure 1E is a schematic side view of an electronic module wherein the integrated device die is wire-bonded to the carrier by bond wires. Fig. 2 is a schematic top view of an imaging system according to an embodiment. Fig. 3 is a three-dimensional schematic perspective view of a portion of an array of electronic modules according to one embodiment. Fig. 4 is a three-dimensional schematic perspective top view of one of the Fig. 3 electronic modules shown. Fig. 5A is a schematic perspective view of a portion of the electronic module illustrating sensor dies, a sensor substrate, and a stiffening element according to some embodiments. Fig. 5B is a side cross-sectional view of the Fig. Part of the electronic module shown in Figure 5A. Fig. Figure 6A is a schematic side view of a die attached to a flexible substrate. Fig. Figure 6B is a schematic side view of the die and flexible substrate after bending the substrate around another support member. Fig. 6C is an image showing a side view of a die according to various embodiments. Fig. 6D is a diagram showing a side view of an integrated device die according to various embodiments. Fig. 7A is a schematic side view of a die and substrate after bending the substrate around a support element according to another embodiment. Fig. Figure 7B is a bottom view of an array of dies after singulation from a wafer. Fig. 7C is an image of a side view of an end portion of an exemplary die. Fig. 7D is an image of a groove shown in an exemplary die attached to a substrate bent around a stiffening element. Fig. Figure 7E is a picture showing a second portion of the adhesive disposed in a groove. Fig. 8 is a flowchart illustrating a method of assembling an electronic module according to various embodiments. Fig. 9 is a flowchart illustrating a method of assembling an electronic module according to another embodiment. DETAILED DESCRIPTION

[0036] Various embodiments disclosed herein relate to an electronic module comprising an integrated device die attached to a carrier. The integrated device die may be attached to the carrier with a compound, such as an underfill or an adhesive, between the integrated device die and the carrier. In some electronic modules, the compound may extend laterally outward past an outside edge of the integrated device die. In such arrangements, the outwardly extending adhesive may interfere with adjacent components. If the compound extends beyond the outside edge of the integrated device die, the compound may occupy excessive space or interfere with adjacent features of the module. Often, the compound is organic, such as a plastic or epoxy material applied in liquid form and then cured or otherwise hardened.

[0037] Thus, in various embodiments disclosed herein, an electronic module may include a carrier and an integrated device die having a top surface, a bottom surface, and an outside edge. The integrated device die may include a recess. The integrated device die may include a first surface recessed from the bottom surface and a second surface extending between the bottom surface and the first surface. The second surface may be laterally recessed from the outside edge. The electronic module may include a ground having a first portion disposed between the bottom surface of the integrated device die and the carrier. The ground may include a second portion disposed along at least a portion of the second surface of the integrated device die or at least a portion of the recess.Advantageously, the compound can be laterally embedded with respect to the outer edge of the integrated component die so that the adhesive does not interfere with adjacent components.

[0038] Fig. 1A is a schematic side view of an electronic module 1 comprising an integrated device die 2 attached to a carrier 3, according to various embodiments. Fig. Figure 1B is an enlarged schematic side view of an end portion of the electronic module 1 of Fig. 1A. In various embodiments, the electronic module 1 may comprise a sensor module or any other type of electronic component. In some embodiments, the electronic module 1 may comprise an integrated component package. The carrier 3 of the Fig. 1A-1B may comprise any suitable carrier. For example, in some embodiments, the carrier 3 may comprise a package substrate, such as a flexible substrate comprising a non-conductive material and a plurality of embedded metal traces, a printed circuit board (PCB), a leadframe substrate, a ceramic substrate, etc. In other embodiments, the carrier 3 may comprise another integrated device die, an interposer, or any other suitable type of carrier. The integrated device die may comprise any suitable type of integrated device die, including, for example, a sensor die, a processor die, a memory die, a microelectromechanical system (MEMS) die, etc. As shown in Fig. 1A, in some embodiments, a footprint of the carrier 3 may be smaller than a footprint of the die 2. For example, in some embodiments, the integrated device die 2 may be laterally larger than or at least as wide as (e.g., as wide as or wider than) the carrier 3. In some embodiments, such relative dimensions may help to more accurately place two or more modules 1 next to each other than a module with the carrier 3 being larger than the die 2.

[0039] The integrated device die 2 may have a top surface 5 and a bottom surface 6 opposite the top surface 5. The top surface 5 may be a surface on a top side of the integrated device die 2, and the bottom surface 6 may be a surface on a bottom side of the integrated device die 2. In some embodiments, active components (e.g., active circuitry) may be provided on or near the bottom surface 6 of the die 2. The integrated device die 2 may have one or more outer side edges 7 defining an outer perimeter of the die 2. As shown in Fig. 1B, the integrated device die 2 may be at least partially attached to the carrier 3 by a ground 4. In the illustrated embodiment, for example, a plurality of solder balls 16 may electrically connect first contact pads (not shown) on the bottom surface 6 of the integrated device die 2 to corresponding second contact pads (not shown) on the carrier 3. In such embodiments, the ground 4 may include an underfill material (e.g., an underfill epoxy) disposed around the plurality of solder balls 16. Thus, the ground 4 may be applied in liquid form, which is passed around the solder balls 16 or connection conductors, to protect and increase the reliability of the electrical connections between the die 2 and the carrier 3 and / or to improve the thermal matching between the die 2 and the carrier 3.In other embodiments, the mass 4 may comprise a die attach material that is not used as an underfill for solder ball connections. For example, the mass 4 may comprise a conventional die attach adhesive applied to the backside of the die 2, and the die 2 may be electrically connected in other ways, such as through bond wires. In another example, the mass 4 may comprise an anisotropic conductive film (ACF) or a non-conductive paste (NCP) applied to the frontside of the die 2 to perform electrical, adhesive, and / or protective sealing functions.

[0040] As in Fig. 1B, the integrated device die 2 may further include a first surface 8 recessed from the bottom surface 6 and a second surface 9 extending between the bottom surface 6 and the first surface 8, wherein the second surface 9 is laterally recessed from the outer side edge 7 of the die 2. The first surface 6 and the second surface 8 may together define at least a portion of a recess 20 formed on the bottom side of the die 2. The recess 20 may have any desired shape. The mass 4 may include a first portion 4a disposed between the bottom surface 6 of the integrated device die 2 and the carrier 3 and a second portion 4b disposed along at least a portion of the second surface 9 of the integrated device die 2.When applied in liquid form, prior to curing or hardening, capillary action may help draw the mass 4 around the solder balls 16 (or other connecting conductors) and may draw the mass 4 from between the bottom surface 6 and the carrier 3, so that the second portion 4b of the mass 4 may contact a portion of the second surface 9 between the first surface 8 and the carrier 3 or may be disposed in at least a portion of the recess 20. In some embodiments, the second portion 4b may also contact the first surface 8. As shown in FIG. Fig. 1B, the first and second parts 4a, 4b of the mass 4 may comprise a continuous material. As shown in Fig. 1B, the mass 4 (e.g., both the first and second parts 4a, 4b) may be further recessed laterally with respect to the outer side edge 7 of the die 2. In some embodiments, the second part 4b of the mass may extend inwardly at an angle from the carrier 3 to the die 2, as shown in Fig. 1B. In some embodiments, the second part 4a may have a concave or convex surface. Advantageously, by providing the negative fillet such that it is located within the contour of the outer side edge 7 of the die 2, the outer side edge 7 of the die 2 may be allowed to abut and / or be closely spaced with respect to an adjacent component, such as another integrated device die.

[0041] As in Fig. 1B, a depth D of the first surface 8 with respect to the bottom surface 6 may be selected to be large enough to accommodate the negative fillet associated with the second portion 4b of the mass, but small enough to avoid weakening the die. In some embodiments, the depth D may be in a range of 100 micrometers to 300 micrometers, or in a range of 100 micrometers to 250 micrometers for a die with a thickness of 500 micrometers, for example, in a range of 100 micrometers to 120 micrometers. In some embodiments, the depth D may be in a range of 20% to 50% of the thickness of the die 2, for example, in a range of 20% to 30% of the thickness. The second portion 4b of the attachment mass 4 may have a fillet distance S extending outside the second surface 9.The second surface 9 may be recessed from the outer side edge 7 by a width W of an overhanging region 18 of the die 2, as measured from the outer side edge 7 of the die. In some embodiments, the width W of the overhanging region 18 may be in a range from 100 micrometers to 500 micrometers. The overhanging region 18 (and the first and second surfaces 8, 9) may be defined in any suitable manner. For example, in some embodiments, the overhanging region 18 may be defined by providing a step cut (e.g., a saw cut) through a portion of the thickness of the die 2, for example, by partially sawing through the bottom surface 6. In other embodiments, the overhanging region 18 may be defined by etching, laser cutting, drilling, or any other suitable method.Therefore, in some embodiments, a relative angle between the first and second surfaces may not be 90°, as shown in FIGS. Fig. 1A and Fig. 1B. Furthermore, the first and second surfaces may not be flat, as shown in the Fig. 1A and Fig. 1B illustrates.

[0042] Fig. Figure 1C is an enlarged schematic side view of an end portion of an electronic module 1 according to another embodiment. Unless otherwise stated, Fig. 1C shown components are equal to numbered components in the Fig. 1A and Fig. 1B or be generally similar. As with the embodiment of the Fig. 1A and Fig. 1B, the die 2 may be attached to the carrier 3. The die 2 may have a top surface 5, a bottom surface 6, a first surface 8 recessed with respect to the bottom surface 6, and a second surface 9 extending between the first surface 8 and the bottom surface 6. A first part 4a of the mass 4 may be arranged around solder balls 16 between the bottom surface 6 of the die 2 and the carrier 3. A second part 4b (for example, a negative fillet) of the mass 4 may be provided along at least a part of the second surface 9 and may be laterally recessed with respect to the outer side edge 7 of the die 2.

[0043] In contrast to the Fig. 1B, a recess 20 of the die 2 may include a groove 19 partially defined by the lower surface of the die 2. The groove 19 may define the first and second surfaces 8, 9 and a third surface 17. The second and third surfaces 9, 17 may be located on opposite sides of the groove 19. The third surface 17 may extend between the first surface 8 and the lower surface 6. The groove 19 may be partially defined compared to the embodiment shown in Fig. 1B can advantageously reduce chipping and / or increase strength. As with the Fig. 1A-1B, the groove 19 may be formed by sawing, etching, laser cutting or drilling or any other suitable method.

[0044] Furthermore, the groove 19 may have a width W and a depth D defined for receiving the second part 4b of the adhesive 4. In some embodiments, the depth D may be in a range of 100 micrometers to 300 micrometers or in a range of 100 micrometers to 250 micrometers for a die with a thickness of 500 micrometers, for example, in a range of 100 micrometers to 120 micrometers. In some embodiments, the depth D may be in a range of 20% to 50% of the thickness of the die 2, for example, in a range of 20% to 30% of the thickness. A width W of the groove 19 may be greater than a fillet distance S, which represents the width of the second part 4b of the adhesive 4. In some embodiments, the width W of the groove 19 may be in a range of 100 micrometers to 500 micrometers. As further shown in Fig. 1C, the groove 19 may have fillets 38 at the corner regions of the groove 19. It should be appreciated that in some embodiments, the fillet 38 may be arranged only at one of the corner regions. The fillet 38 along the corner region of the groove 19 may improve die strength and have a sufficient radius to increase die breakout strength. In various embodiments, a radius of the fillets 38 may be in a range of 2 mm to 4 mm. Although the fillets 38 are shown in connection with the groove 19, it should also be appreciated that the fillets 38 may also be arranged in the Fig. 1A-1B shown step cut embodiment.

[0045] Fig. Figure 1D is a schematic side view of an electronic module 1, wherein the integrated component die 2 is wire-bonded to the carrier 3 by bonding wires 36. The electronic module 1 of Fig. 1D is generally similar to the electronic module 1 of Fig. 1B, except that in Fig. 1D, the die 2 is wire-bonded to the carrier by means of bonding wires 36. In the embodiment of Fig. 1D, the fixing compound 4 may comprise a die attach adhesive for attaching the die 2 to the carrier 3. As in the Fig. 1B, the die 2 may include a recess 20. Advantageously, the overhanging portion 18 of the die 2 may mitigate and / or prevent the mass 4 from reaching, touching, or moving to the surface of the die 2.

[0046] Fig. 1E is a schematic side view of an electronic module 1, wherein the integrated component die 2 is wire-bonded to the carrier 3 by bonding wires 36. The electronic module 1 of Fig. 1E is generally similar to the electronic module 1 of Fig. 1C, except that in Fig. 1E, the die 2 is wire-bonded to the carrier by means of bonding wires 36. In the embodiment of Fig. 1E, the attachment compound 4 may comprise a die-attach adhesive for attaching the die 2 to the carrier 3. Advantageously, the groove 19 of the die 2 may reduce and / or prevent the compound 4 from reaching, reaching, or moving to the surface of the die 2. Examples of electronic modules using a negative fillet adhesive for attaching a die to a carrier

[0047] The negative fillet adhesives disclosed herein can be used with any type of electronic module. Fig. Figure 2 illustrates an imaging system 10 according to one embodiment that uses such negative fillet adhesives. In some embodiments, the imaging system 10 may be a computed tomography (CT) scanner. CT scanners are useful in a wide variety of fields, including medical imaging, industrial imaging, non-destructive testing, and subsurface imaging. In the imaging system 10 of Fig. 2, a source 11 may emit radiation 12 toward an object 13 to be imaged (e.g., a patient). In one embodiment, the source 11 emits x-rays. Those skilled in the art will recognize that there are various conventional mechanisms for delivering radiation for imaging purposes. After a portion of the radiation 12 traverses the object 13, it reaches a one-dimensional (1D) or two-dimensional (2D) array of electronic modules 101 (e.g., sensor modules) positioned opposite the source 11. The electronic modules 101 may be configured to convert detected radiation (e.g., visible light) into electrical signals using a photodiode array (PDA), which may be the sensor of this imaging example.In some implementations, the electronic module 101 may also be configured to convert detected X-rays into visible light, or the system 10 may include a separate scintillator for this purpose. In other implementations, detected X-rays may be converted into electrical signals in other ways. The electronic module 101 is also configured to convert the analog signals received from the PDA into digital signals that can be transmitted through transmission elements 15 to an external control module 14. The electronic module 101 may also perform various other preprocessing and / or preconditioning operations on the detected signals before transmission to the control module 14.After the control module 14 receives the processed digital signals, the control module 14 may further process the digital signals into a readable output, such as an image on a display device or a report with various measured values ​​calculated from the received signals. To obtain a full 3D image of the object 13, the system 10 may be in the mode shown in FIG. Fig. 2 around the object 13 in the direction A shown in order to obtain images of the object 13 at different angles.

[0048] In other embodiments, the imaging system may be an ultrasound device. Although an ultrasound device is not explicitly illustrated here, it should be understood that an ultrasound device, according to some embodiments, may include a source of ultrasonic waves and a detector (or detector array) having one or more electronic modules similar to those described in more detail below. Furthermore, the electronic module(s) may be used in nuclear imaging implementations, such as PET scans, and imaging techniques using gamma rays. In still other embodiments, the electronic modules may be used in various non-imaging assemblies, for example, electrical, electronic, or optical applications that employ a compact module including both a sensor and a processor.For example, MEMS (microelectromechanical systems) devices, such as MEMS microphones and MEMS accelerometers, may include both a sensor die and a processor die near the sensor for processing signals from the sensor. In these embodiments, similar electronic modules to those illustrated here may be useful in providing a compact sensor package while simultaneously thermally isolating the sensor from the processor.

[0049] Fig. 3 is a three-dimensional schematic perspective view of a portion of an array of electronic modules 101. As in Fig. 3, each electronic module 101 may be attached to a holder 130 that is part of a larger imaging system 110. The imaging system 110 may be similar to the one described above with reference to Fig. 2 described imaging system 10 or be similar to it. For example, the imaging system may include a CT device, an X-ray device, an ultrasound device, etc. In the example of Fig. 3, four electronic modules 101 (for example, four sensor modules) are positioned in a string 117 extending along a longitudinal x-axis, but it should be understood that more or fewer than four modules 101 may be positioned side by side in the string 117 along the x-axis. Although in Fig. 3, the array of modules 101 may comprise a plurality of strands 117 arranged adjacent to one another along a direction transverse to the x-axis. In some embodiments, the strands 117 may be positioned along a curved surface, with each strand 117 representing one of the modules 1 of Fig. 2. As in Fig. For example, as shown in Figure 3, the y-axis of the illustrated strand 117 may be tangential to the curved surface along which the array of modules 101 is positioned. In various arrangements, a patient may be positioned within the curved surface of the array, and the system 110 may image portions of the patient's body.

[0050] As in Fig. 3, the electronic modules 101 may be mounted on a front side of the holder 130, and one or more heat sinks 140 may be arranged on a back side of the holder 130. Each heat sink 140 may include fins or other heat transfer elements that can effectively dissipate heat generated by the modules 101 to the atmosphere. In some embodiments, a fan may direct air over the heat sink 140 to enhance heat dissipation from the modules 101; in other embodiments, the heat sink 140 may be exposed to ambient air without the use of a fan. As shown in Fig. 3, a connector substrate 105 may also be provided from each module 101 for connection to an external control module similar to the one described above in connection with Fig. 2 may correspond to or be similar to the control module 14 described above. As shown in Fig. 3, it may also be important to arrange adjacent modules 101 along the holder 130 at a small gap from each other so that adjacent modules 101 do not touch each other.

[0051] Fig. 4 is a three-dimensional schematic perspective top view of the Fig. 3. The electronic module 101 may comprise one or more sensor dies 102 mounted on a flexible sensor substrate 103. Thus, the sensor substrate 103 may be Fig. 4 than the one in the Fig. 1A-1C. Although the substrate is referred to as a "flexible" substrate 103 for simplicity, it should be understood that during the course of assembly, including bonding the substrate 103 to other parts, the substrate may become inflexible. The sensor substrate 103 may be a flexible substrate with integrated bond pads, leads, and traces, allowing for a low profile. The sensor substrate 103 may include a plurality of leads configured for electrical coupling to external devices or substrates. In some embodiments, the sensor die 102 may be mechanically and electrically coupled to the sensor substrate 103 using a gold thermocompression bond with copper leads.In other embodiments, the sensor die 102 may be soldered to the sensor substrate 103, while in still further embodiments, the sensor die 102 may be coupled to the sensor substrate 103 using ACF or NCP technologies.

[0052] For arrangements where it is desirable for the substrate to conform to a specific geometry employed in a system, flexible substrates can be useful. Flexible substrates can be made from a flexible plastic material, such as polyimide or PEEK, and can have integrated bond pads, traces, and lines similar to those used in conventional PCB substrate technologies. The flexible substrate can be easily bent or folded to conform to a specific geometry, allowing contacting of downstream components in a wide variety of configurations. Furthermore, traces and lines can be patterned in very small dimensions on the flexible substrate. For example, in some embodiments, the traces can have line widths and pitches on the order of approximately 15 to 20 micrometers, and the lines or bond pads can have widths or diameters of approximately200-300 micrometers with a similar spacing, so the pitch is on the order of 400-600 micrometers. By using a small line pitch, it is possible for the sensor substrate to electrically communicate with a large number of pixels (e.g., corresponding to portions of the PDA), which can advantageously increase the resolution of the imaging device. In one embodiment, each of the four illustrated sensor dies 102 can be configured for a total of 1920 pixels in the array shown in . Fig. 3 may have 480 pixels electrically coupled to the sensor substrate 103. In other embodiments, each sensor die may have a fewer or higher number of pixels, including, for example, 512 pixels per sensor die. In still other embodiments, the line widths and pitches may be much smaller or larger depending on the desired line density for a particular arrangement. The dimensions of the electronic module 1 may vary depending on the desired implementation. For example, in some embodiments, the illustrated four-die electronic module may have an overall length in a range of about 60 mm to about 100 mm and a width in a range of about 20 mm to about 30 mm. The height or thickness of the electronic module 1 may be relatively small, for example, in a range of about 5 mm to about 10 mm in some embodiments.

[0053] In some embodiments, the sensor die 102 may include an x-ray scanning device, including, for example, a photodiode array (PDA) or other image sensor. As shown in Fig. 4, the module 101 may also include a collimator (not shown) and a scintillator 141 for converting the x-rays into visible light in X-ray applications. The converted visible light may then be received by the sensor die 102, which may convert the visible light into an electrical signal. Alternatively, the collimator and scintillator may be provided separately within the imaging system across the module. In still further embodiments, the sensor die may include any other suitable device configured to detect signals, including, for example, MEMS sensors and other electrical and electronic sensors. In the embodiment of Fig. 4, the electronic module 101 comprises two sensor dies 102, but in other embodiments it is possible to use only one, three, four or more than four sensor dies.

[0054] Again on Fig. 4, the sensor substrate 103 may be attached or coupled to a portion of a stiffening member 104. The stiffening member 104 may provide structural support to the electronic module 101 and may assist in thermally isolating the sensor dies 102 from the processor dies, as described in U.S. Patent Application No. 14 / 805,835, which is incorporated herein by reference. As discussed in more detail below, the sensor substrate 103 may be wrapped around the stiffening member 104. For example, a lower segment of the sensor substrate 103 may be folded or wrapped around a first lateral side 104a of the stiffening member 104 (see Fig. 5A-5B). The end of the flexible sensor substrate 103 wrapped around the stiffening member 104 may be electrically coupled to a flexible processor substrate, as illustrated and described in U.S. Patent Application No. 14 / 805,835. The stiffening member 104 may be made of any suitable material, such as a metal, for example, zinc or aluminum. In other arrangements, the stiffening member 104 may be made of a plastic or a ceramic. The stiffening member 104 and the sensor substrate 103 may be disposed over a carrier 118 configured to support the processor substrate(s).

[0055] Furthermore, a connector substrate 105 may extend from the outer surface of the electronic module 101. The connector substrate 105 may connect the processor substrate(s) (not shown) to the external controller (such as the controller 14 of Fig. 2), which may be positioned remotely from the electronic module 101. The connector substrate 105 may also be made of a flexible material, such as a pigtail, and may include embedded metallic traces and conductive contacts configured for electrical connection to the processor substrate(s).

[0056] Fig. 5A is a schematic perspective view of a portion of the electronic module 101 illustrating the sensor dies 102, the sensor substrate 103, and the stiffening element 104 according to some embodiments. Fig. 5B is a side cross-sectional view of the Fig. 5A. It may be important to provide a reliable electrical connection between the sensor dies 102 and the sensor substrate 103, while maintaining a reliable electrical connection between adjacent electronic modules 101, such as the adjacent modules 101 in a string 117 (see Fig. 3), a sufficiently small distance is maintained. In some embodiments, the sensor dies 102 may be formed using multiple solder balls (similar to the solder balls 16 of Fig. 1B-1C) or other connecting conductor to the sensor substrate 103. An adhesive similar to the adhesive 4 of Fig. 1B-1C (e.g., an underfill epoxy) may be provided between the sensor dies 102 and the sensor substrate 103 and may be routed around the solder balls or interconnect lines to protect and improve the reliability of the electrical connections between the dies 102 and the sensor substrate 103. In some arrangements, when the adhesive is routed between the sensor dies 102 and the substrate 103, the adhesive or epoxy may be squeezed out from the edges of the dies 102 and the substrate 103 and may creep upward along the sides of the dies 102. Such a positive adhesive edge fillet may extend outward relative to the outer perimeter of the electronic module 101. For example, the adhesive may protrude past the perimeter of the sensor dies 102 when viewed in a top view of the module 101.

[0057] In some embodiments, extending a positive adhesive fillet beyond the outer perimeter of the electronic module 101 may be undesirable. For example, since surrounding electronic modules or other system components may be positioned adjacent to a particular electronic module 101, it may be important to ensure that the positive adhesive fillet does not extend beyond the outer perimeter of the die 102 or the sensor substrate 103. In some arrangements, it may be desirable to ensure that the positive adhesive extends less than 50 micrometers outside the outer perimeter of the sensor die 102. If the positive epoxy fillet extends too far outside the perimeter of the die 102, it may be difficult for the end user to assemble adjacent electronic modules or other components.

[0058] Accordingly, in some embodiments, an epoxy underfill may be applied between the sensor dies 102 and the sensor substrate 103 to provide a negative epoxy edge fillet at the edges of the dies 102, as described above in connection with the Fig. 1A-1C. Such a negative fillet may be configured such that it does not extend outside the outer perimeter of the sensor dies 102 (e.g., as viewed in a top or bottom view), thereby ensuring that adjacent electronic modules can be accurately and reliably placed next to each other. In some embodiments, it may be acceptable for a fillet to extend slightly beyond the outer perimeter, for example, by less than 50 micrometers. As shown in Fig. 5A, the sensor substrate 103 may, for example, be wrapped around the first side 104a of the stiffening element 104 such that a curve 103b of the substrate 103 is positioned along the first side 104a. The electronic module 101 may have a first edge 152 arranged along the length of the first side 104a of the stiffening element 104 and a second edge 150 arranged along the length of a second side 104b of the stiffening element 104. As shown in the Fig. 5A and Fig. As shown in Figure 5B, the first edge 152 may be disposed adjacent to the curvature 103b of the substrate 103. The electronic module 101 may also have third and fourth edges 151, 153 opposite each other along the width of the stiffening element 104.

[0059] The sensor dies 102 may be connected to the sensor substrate 103 using multiple interconnects, such as solder balls, and the sensor substrate 103 may be wrapped around the stiffener 104. After wrapping the stiffener 104 with the sensor substrate 103, the underfill epoxy may be placed between the sensor dies 102 and the sensor substrate 103 along the second edge 150, for example, along the edge opposite the curvature 103b of the substrate 103. Capillary action may help draw the underfill epoxy around the solder balls (or other interconnects) and may draw the adhesive or epoxy toward the first edge 152.

[0060] Fig. Figure 6A is a schematic side view of a module 1 having a die 102 attached to a packaging substrate 103. As explained above, the substrate 103 may be the Fig. 1A-1C shown carrier 3. As in Fig. 6A, the substrate 103 may comprise a flexible substrate which may be used prior to mounting a larger electronic module 101, for example, in Fig. 4, unfolded or flat. Thus, prior to wrapping or folding, the substrate 103 may have a larger footprint than the footprint of the die(s) 102. After wrapping or folding, the integrated device die 102 may, in some embodiments, be laterally larger than or at least as wide as the substrate 103. Fig. 6B is a schematic side view of the die 102 and the substrate 103 after wrapping the substrate 103 around a support element in the form of a stiffening element 104. As in the embodiments of the Fig. 1A-1C, the die 102 may have a first surface 8 recessed from the bottom surface 6 of the die 2 and a second surface 9 between the first surface 8 and the bottom surface 6, wherein the second surface 9 is laterally recessed with respect to the outer side edge 7. As in the embodiments of the Fig. 1A-1C, the first portion 4a of the mass 4 (underfill in the illustrated embodiment) may be disposed between the bottom surface 6 and the substrate 103 (e.g., a carrier) and may surround the solder balls 16. The second portion 4b of the mass 4 may be laterally recessed relative to the outside edge 7. Furthermore, the ends of the stiffening element 104 and a curvature 103b relative to the outside edge 7 may also be laterally recessed. By recessing the stiffening element 104, the curvature 103b of the substrate 103, and the mass 4 relative to the outside edge 7, adjacent components can be placed in close proximity to one another.

[0061] Advantageously, the die 102 in the embodiment of the Fig. 6A-6C, the die 102 and substrate 103 may be attached to the die 103 by means of the mass 4 and solder balls 16 prior to incorporating the substrate 103 into a larger electronic module, such as by attaching the substrate 103 to (and wrapping the substrate 103 around) the stiffener 104. Thus, the die 102 and substrate may be inspected for voids or excessive mass leaking beyond the edge 7 of the die 102 (positive fillets) prior to assembly, thereby avoiding the increased costs associated with discarding the assembled module. Furthermore, handling the die 102 and substrate 103 assembly between the attached solder and the underfill poses the risk of damaging the solder joints prior to underfill reinforcement.

[0062] Fig. 6C is a diagram showing a side view of an exemplary die 102 attached to a substrate 103. Fig. Figure 6D is another image showing a side view of an integrated device die 2. As shown in Fig. 6D, the second part 4b of the mass 4 may, for example, have a negative fillet arranged entirely within the outer periphery of the die 2, such that the mass is laterally recessed with respect to the outer side edge 7. The negative fillet defined by the second part 4b may, in some embodiments, have a concave surface, as shown in Fig. 6D. As shown by Fig. 6D, a shape and / or a quantity of the second part 4b may differ at another part of the die 2.

[0063] Fig. Figure 7A is a schematic side view of a die 102 and substrate 103 after wrapping the substrate 103 around the stiffening element 104 according to another embodiment. Unless otherwise stated, the Fig. 7A are the same numbered components in the Fig. 1C and 6A-6D correspond to or be generally similar. As with Fig. 1C, the groove 19 may, for example, be partially defined by a thickness of the die 102. A first part 4a of the mass 4 may be formed around solder balls 16 between the bottom surface 6 of the die 102 (which may comprise a sensor die similar to the sensor die of Fig. 5A-5B) and the carrier 103. A second part 4b (for example, a negative fillet) may be provided along at least a part of the second surface 9 and may be laterally recessed with respect to the outer side edge 7 of the die 102. As in Fig. 1C, the groove 19 may reduce chipping and / or maintain the structural integrity of the die 102 compared to the embodiment of Fig. 6A-6D maintained.

[0064] Furthermore, the groove 19 may have a width W and a depth D defined to accommodate the second part 4b of the mass 4. In some embodiments, the depth D may be in a range of 100 micrometers to 300 micrometers or in a range of 100 micrometers to 250 micrometers for a die with a thickness of 500 micrometers, for example, in a range of 100 micrometers to 120 micrometers. In some embodiments, the depth D may be in a range of 20% to 50% of the thickness of the die 2, for example, in a range of 20% to 30% of the thickness. A width W of the groove 19 may be greater than a fillet distance S, which represents the width of the second part 4b of the mass 4. In some embodiments, the width W of the groove 19 may be in a range of 100 micrometers to 500 micrometers.

[0065] Fig. 7B is a bottom view of an array of dies 102 after singulation from a wafer 35. The dies 102 may be defined at the wafer level and subsequently singulated to define a plurality of singulated dies. Furthermore, the wafer-level groove 19 or slot may also be formed by performing a plurality of partial saw cuts along an edge portion of the dies 102 on a backside of the wafer 35 prior to singulation. In embodiments where two dies 102 are attached to each other on a single carrier, each die 102 of the pair may have only one groove at an end portion of the die 102. The dies 102 may be singulated from the wafer 35 by sawing through the wafer along saw streets 30. In other embodiments, depending on which sides of the die are to be protected from leaking compound beyond the die edge during application in liquid form, partial saw cuts, grooves 19 or step cuts (see Fig. 6B) along 1, 2, 3 or 4 edge regions of each die.

[0066] Fig. 7C is an image of a side view of an end portion of an exemplary die 102. Fig. 7D is an image of a groove 19 shown in an exemplary die 102. Fig. 7E is an image showing the second portion 4b of the mass 4 (e.g., the negative fillet) disposed in the groove 19. As explained above, the second portion 4b may advantageously be provided in the groove 19 and may not extend outward past the outer side edge 7 of the die 102.

[0067] Fig. 8 is a flowchart illustrating a method 80 for assembling an electronic module according to various embodiments. In a block 81, an integrated device die may be attached to a carrier with solder balls. For example, first contact pads on the bottom surface of the integrated device die may be electrically connected to corresponding second contact pads on the carrier. In some embodiments, the carrier may comprise a flexible substrate having conductive traces embedded in a non-conductive material. The integrated device die may comprise any suitable type of die, such as a photosensitive die, such as an image sensor die. The integrated device die may have a top surface, a bottom surface, and an outside edge.The integrated device die may include a first surface recessed from the bottom surface and a second surface extending between the bottom surface and the first surface. The second surface may be laterally recessed from the outer side edge. In some embodiments, the first and second surfaces may define an overhanging portion of the die, such as the portion shown in FIGS. Fig. 1B and 6A-6D. In other embodiments, a groove may be partially defined by the bottom surface of the die. The first surface, the second surface, and a third surface may at least partially define the groove. The third surface may extend between the first surface and the bottom surface. The first and third surfaces may be located on opposite sides of the groove.

[0068] Referring to block 82, an underfill compound may be provided around the plurality of solder balls. As explained above, capillary action may draw the underfill adhesive between the die and the carrier. A first portion of the compound may be disposed between the bottom surface of the integrated device die and the carrier. A second portion of the compound may be disposed along at least a portion of the second surface of the integrated device die. In various embodiments, the compound does not contact the outside edge of the integrated device die. The underfill compound may be cured using heating, exposure to radiation (e.g., ultraviolet radiation), or any other suitable curing method to harden the compound. The underfill fillet may be inspected to ensure adequate adhesion between the carrier and the die and to monitor the size and quality of the fillet.

[0069] Referring to block 83, the carrier may be attached to a support member. In embodiments where the carrier comprises a flexible substrate, the flexible substrate may be wrapped around a portion of a stiffening member. Advantageously, in various embodiments, the integrated device die may be attached to the carrier, and the underfill may be provided and cured before the carrier is attached to the stiffening member and prior to wrapping. As discussed above, by providing the compound prior to attaching the carrier to the stiffening member, the ability to inspect the underfill fillet may be improved. However, in other embodiments, the carrier may be attached to the stiffening member prior to providing the compound.

[0070] Fig.9 is a flowchart illustrating a method 90 for assembling an electronic module according to another embodiment. In a block 91, an integrated device die may be attached to a carrier with an attachment compound. The integrated device die may have a top surface, a bottom surface, and an outside edge. The integrated device die may have a first surface recessed from the bottom surface and a second surface extending between the bottom surface and the first surface. The second surface may be laterally recessed from the outside edge. The attachment compound may have a first portion disposed between the bottom surface of the integrated device die and the carrier. A second portion of the attachment compound may be disposed along at least a portion of the second surface of the integrated device die.In some embodiments, as discussed above, the die may be physically and electrically connected to the carrier with multiple solder balls, and the attachment compound may comprise an underfill epoxy that is routed around the solder balls and cured. In other embodiments, the attachment compound may comprise a die attach material or a die attach adhesive, and the die may be wire-bonded to the carrier. In various embodiments, the attachment compound may comprise ACF or NCP.

Claims

[1] Electronic module (1), comprising: a package substrate (3) arranged on a holding structure, in particular a stiffening element (104); an integrated component die (2) having a top side (5), a bottom side (6) and an outer side edge (7), the bottom side (6) having a first part and a recess (20) at or near the outer side edge (7), the integrated component die (2) being laterally at least as wide as the support structure; and a fixing compound (4) having a first part (4a) arranged between the first part of the integrated component die (2) and the package substrate (3) and a second part (4b) arranged along at least a part (9) of the recess (20) of the integrated component die (2), wherein the fixing compound (4) is laterally recessed with respect to the outer side edge (7) of the integrated component die (2). [2] The electronic module (1) of claim 1, further comprising a plurality of electrical connecting conductors electrically connecting first contact pads on the first part of the integrated component die (2) to corresponding second contact pads on the package substrate (3), wherein the mounting compound (4) comprises an underfill material arranged around the plurality of electrical connecting conductors. [3] Electronic module (1) according to claim 1 or 2, further comprising an active circuit arrangement on or near the bottom (6) of the integrated component die (2) or on or near the top (5) of the integrated component die (2). [4] Electronic module (1) according to any preceding claim, wherein the fastening mass (4) has a concave surface. [5] An electronic module (1) according to any preceding claim, wherein the package substrate (3) comprises a flexible substrate comprising a non-conductive material with embedded metal traces, and the electronic module further comprises a stiffening element (104), the flexible substrate being wrapped around a portion of the stiffening element (104). [6] Electronic module (1) according to any preceding claim, wherein the integrated component die (2) comprises a sensor die (102). [7] Electronic module (1) according to any preceding claim, wherein the recess (20) is laterally recessed from the outer side edge (7) in a range of 100 micrometers to 500 micrometers. [8] Electronic module (1) according to any preceding claim, wherein the recess (20) has an inclined wall extending between the first part and the outer side edge (7). [9] An electronic module (1) according to any preceding claim, wherein the recess (20) comprises a groove (19) having a first wall extending vertically from the first part to the upper surface and a second wall, the first and second walls being arranged on opposite sides of the groove (19). [10] Electronic module (1), comprising: a package substrate (3) having a fastening section and a curved section (103b) which is bent around a holding structure, in particular a stiffening element (104), relative to the fastening section; an integrated component die (2) having a top surface (5), a bottom surface (6) and an outer side edge (7), the bottom surface (6) having a mounting surface and a groove (19) recessed by the outer side edge (7); and a fastening mass (4) arranged between the fastening surface of the integrated component die (2) and the fastening section of the package substrate (3), wherein the fastening mass (4) is laterally recessed from the outer side edge (7). [11] Electronic module (1) according to claim 10, wherein a part of the fastening mass (4) is arranged in the groove (19) of the integrated component die (2). [12] The electronic module (1) according to claim 10 or 11, wherein the integrated device die (2) comprises a first part having a first average thickness, a second part having a second average thickness thinner than the first average thickness, and a third part depending from the second part, the groove (19) being formed between the first part and the third part. [13] Electronic module (1) according to any one of claims 10-12, wherein the groove (19) partially surrounds the mounting surface of the lower surface. [14] The electronic module (1) according to any one of claims 10-13, further comprising a lead wire electrically connecting a first contact pad on the upper surface of the integrated device die (2) to a second contact pad on the package substrate (3). [15] The electronic module (1) of any one of claims 10-14, further comprising a plurality of solder balls electrically connecting first contact pads on the bottom surface of the integrated device die (2) to corresponding second contact pads on the package substrate (3), wherein the mounting compound (4) comprises an underfill material disposed around the plurality of solder balls. [16] Electronic module (1) according to any one of claims 10-15, further comprising active circuitry on or near the bottom surface of the integrated device die (2). [17] Electronic module (1) according to one of claims 10-16, wherein the fastening mass (4) is laterally recessed with respect to the outer side edge (7) of the integrated component die (2). [18] Electronic module (1), comprising: a means for attaching an integrated component die (2) to a package substrate (3) arranged on a holding structure, in particular a stiffening element (104), wherein the integrated component die (2) has a top side (5), a bottom side (6) and an outer side edge (7), wherein the bottom side (6) has a first part and a means for receiving the fastening means at or near the outer side edge (7), wherein the integrated component die (2) is laterally at least as wide as the holding structure, in particular the stiffening element (104), and wherein the fastening means comprises a first part arranged between the first part of the integrated component die (2) and the package substrate (3), and a second part arranged along at least a part of the means for receiving the fastening means, and wherein the fastening means (4) does not extend outwards past the outer side edge (7). [19] The electronic module (1) of claim 18, wherein the fastening means comprises an underfill material and the receiving means comprises a recess (20) preventing the fastening means from moving to the top side (5) of the integrated device die (2).

Images