The present disclosure relates to electronics packaging, and more particularly, to an electronic device package (e.g., surface-mount device (SMD) package) including a gel.
An electronic device packaged for direct mounting to the surface of a printed circuit board (PCB) is commonly referred to as a Surface Mount Device (SMD) package. An SMD package may include various integrated circuit components and/or discrete electronic components. The process for mounting an SMD to a PCB is referred to as Surface Mount Technology (SMT). SMD packaging is often expensive to implement, for example for packaging certain power module devices (SMD power packages).
SMD power packages are typically over-molded using a transfer molding machine. For example, a conventional transfer molded SMD power package may be formed by arranging an electronic device (e.g., substrate with die(s) or other circuitry mounted there) in a reusable mold tool (e.g., a metal mold), dispersing a mold compound in the mold tool to encapsulate the electronic device, and removing the mold-encapsulated electronic device from the reusable mold tool. One drawback of this packaging technique is that a new mold tool may be needed for each different or unique package geometry or design, which may be very expensive.
There is a need for improved and electronics packages and packaging techniques, including SMD packages and packaging techniques.
Some examples provide an electronic device package, e.g., an SMD package, including an electronic device mounted to a frame and filled with a gel. For example, an SMD package (e.g., an SMD power module package) may include an electronic device including electronic circuitry provided on an electronic device substrate (e.g., one or more IC dies wire bonded to metal lines or other circuitry formed on a ceramic substrate or PCB), and surface-mount leads (e.g., leadframe leads) affixed to the substrate and electrically connected to the electronic circuitry. The electronic device (with the affixed surface-mount leads) may be mounted to the frame, with a gel formed in a cavity between the electronic device and the frame, for example between the electronic device substrate and interior surfaces of the frame. The gel may cover the electronic circuitry of the electronic device, while the surface-mount leads may extend outwardly from an outer perimeter of the gel-filled frame in respective lateral directions.
One aspect provides an electronic device package including a frame, an electronic device mounted to the frame, the electronic device including electronic circuitry provided on an electronic device substrate, surface-mount leads electrically connected to the electronic circuitry and extending laterally and outwardly from an outer perimeter of the frame, and a gel at least partially filling a cavity between the electronic device and the frame, the gel covering the electronic circuitry.
In some examples, the gel fully fills the cavity. In other examples, the gel partially fills the cavity. For example, the gel may fill at least 50% of the cavity, at least 75% of the cavity, at least 90% of the cavity, or at least 95% of the cavity, depending on the particular example.
In some examples, the gel comprises an elastomer gel. For example, the gel may comprise silicone.
In some examples, the electronic device package comprises a surface-mount device (SMD) package.
In some examples, the electronic circuitry comprises at least one integrated circuit (IC) die mounted on the electronic device substrate.
In some examples, a first side of the electronic device substrate is exposed through an opening defined by the frame.
In some examples, a first side of the electronic device substrate is exposed through an opening at a first side of the electronic device package, and the surface-mount leads extend outwardly from the outer perimeter of the frame at a second side of the electronic device package.
In some examples, the surface-mount leads comprise leadframe leads affixed to the electronic device substrate.
In some examples, the frame is formed from a ceramic filled plastic or silicon nitride (SiN).
In some examples, the frame comprises multiple frame components assembled together.
In some examples, the frame comprises a frame base and a frame lid securable to the frame base.
In some examples, the frame base comprises a closed-loop rectangular structure, and the electronic device is mounted in an opening defined by the closed-loop rectangular structure of the frame base.
In some examples, the frame base includes multiple frame base components securable to each other by mechanical connection.
In some examples, the frame lid includes (a) a frame lid plate portion spaced apart from the electronic device and (b) at least one frame lid structural support member projecting perpendicular to the frame lid plate portion, the at least one frame lid structural support member contacting the electronic device to provide structural support for the electronic device package.
In some examples, the electronic device is secured to the frame base, wherein a first side of the electronic device substrate is exposed through an opening defined by the frame base, the frame lid is secured over a second side of the electronic device substrate, and the gel is formed between the second side of the electronic device substrate and the frame lid.
Some examples provide a method of assembling an electronic device package, including (a) affixing surface-mount leads to an electronic device comprising electronic circuitry provided on an electronic device substrate, wherein the surface-mount leads are electrically connected to the electronic circuitry, (b) mounting the electronic device to a frame base, wherein the surface-mount leads extend outwardly from an outer perimeter of the frame base, (c) depositing a gel over the mounted electronic device, and (d) securing a frame lid to the frame base, wherein the gel at least partially fills a cavity between the mounted electronic device and the frame lid.
In some examples, affixing surface-mount leads to the electronic device includes providing a leadframe including leadframe leads extending from a leadframe lead carrier structure, and affixing the leadframe leads to the electronic device substrate of the electronic device.
In some examples, the method includes comprising cutting away the leadframe lead carrier structure after securing the frame lid to the frame base.
In some examples, the method includes mounting the electronic device to the frame base such that a first side of the electronic device substrate is exposed through an opening defined by the frame.
In some examples, mounting the electronic device to a frame base includes securing the electronic device to a first frame base component, and securing a second frame base component to the first frame base component.
In some examples, the method includes using a vacuum dispensing process to fill the cavity with the gel.
In some examples, the method includes performing a curing process to cure the gel.
In some examples, the method includes securing the frame lid to the frame base using mechanical connection elements.
In one example, an electronic device package includes a frame base having a closed-loop rectangular structure defining a frame base opening, an electronic device mounted to the frame base, a frame lid secured to the frame base, and a gel at least partially filling a cavity between the electronic device and the frame lid. The electronic device includes electronic circuitry provided on an electronic device substrate, wherein a first side of the electronic device substrate is exposed through the frame base opening.
In some examples, the frame base includes multiple frame base components securable to each other by mechanical connection.
In some examples, the electronic device package includes surface-mount leads affixed to the electronic device and extending laterally and outwardly from an outer perimeter of the frame base.
Example aspects of the present disclosure are described below in conjunction with the figures, in which:
It should be understood the reference number for any illustrated element that appears in multiple different figures has the same meaning across the multiple figures, and the mention or discussion herein of any illustrated element in the context of any particular figure also applies to each other figure, if any, in which that same illustrated element is shown.
As shown in
In the illustrated example, the surface-mount leads 116 comprise leadframe leads affixed to the electronic device substrate 114, e.g., bonded to conductive pathways (e.g., traces) formed on the electronic device substrate 114. As discussed below, leadframe leads may be provided on a leadframe including a leadframe lead carrier structure supporting the leadframe leads; the leadframe leads may be affixed to the electronic device substrate 114 (e.g., by solder or adhesive bonds), and the leadframe lead carrier structure may subsequently be cut away (e.g., after securing the frame lid 122 over the electronic device 104 and gel 106), leaving the leadframe leads affixed to the electronic device substrate 114, e.g., as shown in
The frame 102 at least partially encloses the electronic device 104. For example, as shown in
In some examples, the frame base 120 includes multiple frame base components securable to each other, e.g., by mechanical connection and/or adhesive. For example, the frame base 120 may include a first frame base component 130 and a second frame base component 132 securable to the first frame base component 130, e.g., by mechanical connection (e.g., using clip elements formed in the first frame base component 130 and/or second frame base component 132) or by an adhesive. In the illustrated example, the first frame base component 130 has a “C” shape defining three sides of a closed-loop rectangular shape, and the second frame base component 132 defines the fourth side of the closed-loop rectangular shape. In some examples, the multi-component frame base 120 allows the electronic device 104 to be mounted to the frame base 120 after affixing the surface-mount leads 116 to the electronic device substrate 114, by securing the first and second frame base components 130 and 132 around the perimeter of the electronic device substrate 114, e.g., as shown in
In other examples, the frame base 120 is formed as a single component, e.g., defining a closed-loop rectangular shape.
The electronic device 104 may be supported in and/or affixed to the frame base 120. In the illustrated example, e.g., as shown in
The frame lid 122 may be secured to the frame base 120 in any suitable manner, e.g., by mechanical connection and/or adhesive. In the illustrated example, the frame lid 122 includes clip elements 136 (also shown in
The gel 106 at least partially fills a cavity 140 defined between the electronic device 104 and at least by the frame 102, and covers the electronic circuitry 112 of the electronic device 104. In the assembled state of the electronic device package 100, as more clearly shown in
In some examples, the gel 106 fully fills the cavity 140. In other examples, the gel 106 partially fills the cavity 140. For example, in some examples the gel 106 fills at least 50% of the cavity 140, at least 75% of the cavity 140, at least 90% of the cavity 140, or at least 95% of the cavity 140, depending on the particular example or implementation. References herein to the amount of the cavity 140 filled by the gel 106 (e.g., fully filled, at least 50% filled, at least 75% filled, at least 90% filled, or at least 95% filled) do not account for any internal voids in the gel 106. In some examples, internal voids have a total volume of less than 50%, or less than 10%, or less than 1% of the total volume of the gel 106 in the assembled electronic device package 100.
In some examples, internal voids and/or other non-filled portions of the cavity 140 may correlate with a reduced lifespan of certain electronic circuitry 112 in the electronic device package 100. Accordingly, in some examples, the electronic device package 100 is assembled such that gel 106 fully fills the cavity 140 and includes internal voids having a total volume of less than 1% of the total volume of the gel 106. In some examples, internal voids in the gel 106 may have a bubble size less than or equal to 20 μm.
In some examples, the gel 106 comprises an elastomer or elastomeric material, for example a silicone gel or a silicone-based gel. In some examples, gel 106 may comprise any of the following:
In some examples, the gel 106 comprises a multi-component gel, e.g., including two components mixed together in liquid form (prior to depositing in the cavity 140), and then subsequently cured (e.g., after securing the frame lid 122 to the frame base 120, or otherwise after depositing in the cavity 140) to convert the liquid mixture to a more viscous, gel-like substance. Example gels A, B, D, and E listed above comprise two-component gels.
In other examples, the gel 106 may comprise a single component, e.g., example gel C listed above.
In some examples, the gel 106 may exhibit certain material properties. For example, the gel 106 may exhibit any one or more of the following properties:
In some examples, the consistency of the cured gel 106 (e.g., having a consistency providing a penetration of 3-10 mm using the ASTM D5 penetration test, as listed above) allows bond wires and/or other relatively fragile components of the electronic device 104 to travel through the gel 106, e.g., during thermal expansion or contraction of various components of the electronic device package 100, without damaging the bond wires and/or other fragile or delicate components.
As discussed below with reference to
As shown in
In some examples, the first frame base component 130, the second frame base component 132, and/or the frame lid 122 may be formed using a rapid prototype process or additive printing process (e.g., a 3D additive printing process) from a ceramic-filled plastic resin (e.g., Somos® PerFORM from Koninklijke DSM N.V. based in Heerlen, Netherlands (also known as DSM or Royal DSM)), silicon nitride, or other non-conductive material. Forming some or all of the frame components (e.g., first frame base component 130, the second frame base component 132, and/or the frame lid 122) using a rapid prototype process or additive printing process (e.g., 3D printing) may provide a substantial reduction in manufacturing costs (e.g., by reducing or eliminating non-recurring engineering (NRE) costs), as compared with conventional processes that use an expensive reusable mold tool to form a mold encapsulation on an electronic device, e.g., as discussed in the Background section.
In other examples, the first frame base component 130, the second frame base component 132, and/or the frame lid 122 may be formed by injection molding, casting, or other suitable manufacturing process. In some examples, the first frame base component 130, the second frame base component 132, and/or the frame lid 122 may be formed using a simpler and less expensive mold tool as compared with conventional processes.
In the assembled state of the electronic device package 100, the frame lid plate portion 162 is spaced apart from the electronic device 104 (with gel 106 between the frame lid plate portion 162 and electronic device 104), and the frame lid structural support members 164 may contact the electronic device 104 to provide additional structural support for the electronic device package 100, e.g., to support the weight of structure(s) mounted on the assembled electronic device package 100 (e.g., a heat sink (not shown) mounted on the exposed first side 114a (see
The electronic device 104 may be mounted to the frame base 120 as shown in
As shown in
As discussed above, in other examples the frame base 120 may be formed as a single-piece component, and the electronic device 104 may be mounted to the frame base 120 in a single step.
The electronic device 104 and the assembled frame base 120 partially define the cavity 140 for receiving the gel 106. As shown in
In some examples, the deposited gel 106 completely fills a full height of the cavity 140, e.g., up to a top surface 120a of the frame base 120. In other examples, e.g., as shown in
As shown in
As shown in
As shown in
In some examples the gel 106 may be cured to convert the gel from a liquid state to a semi-solid gel state. For example, a curing process may be performed in a temperature range of 100-150° C. for a duration in the range of 45-120 minutes. The cured gel 106 may exhibit any of the properties listed above. For example, in some examples the cured gel 106 may exhibit (a) a hardness in the range of 50-130 g (for example in the range of 70-110 g) and/or (b) a consistency characterized by 3-10 mm penetration using the ASTM D5 penetration test.
As shown, the gel 106 fills the cavity 140 defined between the second side 114b of the electronic device substrate 114, the interior side 122a of the frame lid 122, and interior sides 120a of the frame base 120, which cavity 140 may be fully enclosed of may include one or more openings.
In some examples, the surface-mount leads comprise leadframe leads carried by a leadframe lead carrier structure, wherein the leadframe lead carrier structure may be cut away at some point after affixing the leadframe leads to the electronic device (e.g., after securing the frame lid to the frame base, or after mounting the electronic device to the frame base but before depositing the gel).
At 612, a gel is deposited on the mounted electronic device (e.g., using a vacuum dispensing process), the deposited gel covering electronic circuitry of the electronic device. At 614, a frame lid is secured to the frame base and over the electronic device, such that the gel at least partially fills a cavity defined between the electronic device substrate and the frame lid, and such that the conductive surface-mount leads extend outwardly from an outer perimeter of the frame in respective lateral directions. At 616, a curing process is performed to cure the deposited gel, e.g., to convert the gel from a liquid state to a semi-solid gel state, as discussed above. At 618, the leadframe lead carrier structure may be cut away and removed, leaving the leadframe leads extending outwardly from the outer perimeter of the frame.
This application claims priority to commonly owned U.S. Provisional Patent Application No. 63/400,431 filed Aug. 24, 2022, the entire contents of which are hereby incorporated by reference for all purposes.
Number | Date | Country | |
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63400431 | Aug 2022 | US |