Packaging for electronics can serve several purposes. For example, packaging can prevent physical damage and corrosion, provide electrical isolation, and enable thermal dissipation for the electronics contained within the packaging. Packaging is increasingly important due to rapid advances in integrated circuit (IC) fabrication and the demands of a growing market in almost all areas of application, such as power electronics, portable electronics, consumer electronics, home electronics, computing electronics, automotive, railway, aerospace and defense, industrial drivers and motor controls, medical devices, and others. However, design and performance requirements for these electronics are demanding, for example within harsh mechanical, thermal, and electrical environments. This can be due to high intrinsic power dissipation of the electronics.
Packages in the electronics industry address the foregoing issues, but they also present challenges for incorporating multiple die with one or more different backside electrical potentials. For example, these packages may use a slug-up, surface mount technology (SMT) package that has less than desirable performance characteristics for the thermal path from the die to a heat sink. These packages may also require an external heat pad to be attached to a pad on the bottom of a printed circuit board (PCB) and may use standard lead frame material as the thermal pad, thereby potentially limiting the thermal performance to that of a large copper area on the PCB. Such configurations have several shortcomings. These shortcomings may include, but are not limited to, the failure to minimize thermal paths for dissipating heat from the internal die, lack of electrical isolation between the internal die and any external heat tab that connects to the heat sink, preventing the heat sink from being kept at a non-zero electrical potential, and preventing full power dissipation of the package. These and other shortcomings are addressed by the methods and systems described herein.
It is to be understood that both the following general description and the following detailed description are exemplary and explanatory only and are not restrictive. Provided are methods and systems for thermally conductive electronic packaging.
An apparatus comprises a circuit board with a metallic base plate, a thermally conductive dielectric, and a plurality of metallic pads. The apparatus further comprises a plurality of die, where each of the plurality of die is coupled to a respective one of the plurality of metallic pads, and the plurality of die comprises a first die and a second die.
Based on each of the plurality of die being coupled to a respective one of the plurality of metallic foil pads, the first die is configured to exhibit a first bottom-side electrical potential, and the second die is configured to exhibit a second bottom-side electrical potential. The apparatus is further configured to conduct heat from the plurality of die away from the plurality of die via at least the metallic base plate, the thermally conductive dielectric, and the plurality of metallic pads.
A method comprises manufacturing a circuit board with a metallic base plate, a thermally conductive dielectric, and a plurality of metallic pads. The method further comprises a step for including a plurality of die, wherein each of the plurality of die is coupled to a respective one of the plurality of metallic pads, and the plurality of die comprises a first die and a second die.
Based on each of the plurality of die being coupled to a respective one of the plurality of metallic foil pads, the first die is configured to exhibit a first bottom-side electrical potential, and the second die is configured to exhibit a second bottom-side electrical potential. The apparatus is further configured to conduct heat from the plurality of die away from the plurality of die via at least the metallic base plate, the thermally conductive dielectric, and the plurality of metallic pads.
Additional advantages will be set forth in part in the description which follows or may be learned by practice. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description, serve to explain the principles of the methods and systems:
Before the present methods and systems are disclosed and described, it is to be understood that the methods and systems are not limited to specific methods, specific components, or to particular implementations. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes.
Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
The present methods and systems may be understood more readily by reference to the following detailed description of preferred embodiments and the examples included therein and to the Figures and their previous and following description.
Certain attempts have been made to achieve electrical isolation of the die within the electronic packaging. One such configuration is disclosed in
Referring now to an aspect of the disclosure according to
Also according to this aspect, the circuit board 240 further comprises a metallic base plate 243, a thermally conductive dielectric 242, and a plurality of metallic pads 241, 261, 271, 281. According to this aspect, the metallic base plate 243 can comprise a layer including any type of conductive material. For example, a 1-2 mm thick layer of copper, aluminum, or other metal. The metallic base plate may be configured to be electrically isolated from the plurality of metallic pads. Also according to this aspect, the thermally conductive dielectric 242 can comprise a layer including any type of non-conductive or electrically insulating material. While described as a dielectric material, the thermally conductive layer can also comprise an insulated metal substrate.
Referring again to an aspect of the disclosure according to
Apparatus 200 may be further configured to conduct heat away from the die 220-221. According to this aspect, the heat from the die 220-221 can be conducted via, for example, at least the metallic base plate 243, the thermally conductive dielectric 242, and the plurality of metallic pads 241, 261, 271, 281. For example, heat resulting from power dissipation or otherwise from the die 220-221 may be conducted from the die 220-221 to the metallic pads 241, 261, 271, 281, through the thermally conductive dielectric 242, through the metallic base plate 243, and away from the apparatus 200 via an external heat tab 244 that may be either part of or separate from the metallic base plate 243 and which can be coupled to a heat sink (not shown).
According to another aspect of the present disclosure, apparatus 200 further comprises a plurality of leads 210-211 that may be configured to be coupled to a second apparatus, such as a separate PCB or other electronics, and to at least one of the die 220 or 221. The leads 210-211 may be electrically coupled to one or more of the die 220 or 221 via, for example, configuring the leads 210-211 to be coupled to one or more of the metallic foil pads 241, 261, 271, 281 which, in turn, are respectively coupled to one or more of the die 220 or 221 via one or more wire bonds 260-262. According to the aspect of
The plurality of metallic pads 241, 261, 271, 281 may further comprise electrically isolated pairs or sets of metallic pads. In one aspect, a first metallic pad 271 and a second metallic pad 261 are electrically isolated from each other, as well as a third pad 281 and a fourth pad 241 that are also electrically isolated from each other. According to this aspect, the first die 220 may be configured to be coupled to the first pad 271, to the second pad 261, and the third pad 281, and the second die 221 may be configured to be coupled to the second pad 261 and a fourth pad 241. For example, the die 220-221 may be configured to be coupled to the metallic pads via one or more wire bonds 260-262, as disclosed above and herein, or via conductive die attach material such as solder, sintered silver paste or silver-filled epoxy.
According to yet another aspect, each of the plurality of metallic pads 241, 261, 271, 281 of apparatus 240 may be configured to be coupled to at least one of the plurality of leads 210-211, and each of the plurality of metallic pads 241, 261, 271, 281 may be coupled to the thermally conductive dielectric 242, while the thermally conductive dielectric 242 may be coupled to the metallic base plate 244. According to another aspect, apparatus 240 may further comprise a heat sink (not shown) coupled to the die 220-221, where the apparatus 240 is further configured to conduct heat away from the die 220-221 to the heat sink. While apparatus 200 is described with reference to two die 220 and 221 for ease of explanation, a person skilled in the art would appreciate that apparatus 200 can comprise any number of die.
Referring now to
Apparatus 500 may be further configured to conduct heat away from the plurality of die 520-522. According to this aspect, heat from die 520-522 can be conducted via, for example, at least the metallic base plate 543, the thermally conductive dielectric 542, and the plurality of metallic pads 531-533. For example, heat resulting from power dissipation or otherwise from die 520-522 may be conducted from the die to the metallic pads 531-533, through the thermally conductive dielectric 542, through the metallic base plate 543, and away from the apparatus 500 via an external heat tab that may be coupled to a heat sink (not shown). Apparatus 500 may further comprise a plurality of leads 510-512 that may be configured to be coupled to a second apparatus, such as a separate PCB or other electronics and to at least one of the die 520-522.
Referring now to
In other aspects, apparatus 600 may further comprise additional die that may include one or more additional custom ICs, transistors, or other types of semiconductor devices that are respectively coupled to additional metallic pads that are electrically isolated from each other and configured to conduct heat away from each of the respective die via the thermally conductive dielectric and the metallic base plate away from the apparatus.
Any apparatus (e.g., the apparatus 100-600, etc.) described herein may be further configured for increased creepage protection between external and/or internal pins of the associated electronic package and metallic baseplate. For example, any apparatus (e.g., the apparatus 200, the apparatus 500, the apparatus 600, etc.) described herein may be further configured with voids (e.g., free space areas, etc.) within its non-conductive housing to artificially lengthen the surface distance between external and/or internal pins of the electronic package and the metallic baseplate.
Any apparatus (e.g., the apparatus 100-600, etc.), as described herein, configured for increased creepage protection between external and/or internal pins of the associated electronic package and metallic baseplate improve any existing configurations by affording two benefits to the design, for example, increased voltage isolation and increased material choices for the non-conductive housing.
For example, creepage requirements are generally more demanding than clearance requirements for high-voltage circuit applications. For increased voltage isolation, by increasing the creepage distance of any apparatus (e.g., the apparatus 100-600, etc.) as described herein greater than the clearance distance, the maximum theoretical voltage isolation may be achieved between two conductors exposed to air and provides additional voltage isolation between a conductive baseplate and the circuitry bonded to it. An increased creepage distance of any apparatus (e.g., the apparatus 100-600, etc.) as described herein places a lower threshold on the required coefficient of creepage distance for any material chosen in the non-conductive housing—providing more flexibility in the material selection of this component.
For any apparatus (e.g., the apparatus 100-700, etc.) described herein, due to the nature of creepage, creepage trenches may be included anywhere between the metallic baseplate and conductive elements that connect electrically to the plurality of die. Additionally, the trenches may be inverted. For example, rather than a void in the housing, a projected wall may be added to the housing to increase both creepage and clearance.
To maintain the positioning of the metallic baseplate for any apparatus (e.g., the apparatus 100-700, etc.) described herein, creepage trenches may be removed in “registering locations.” For example,
Referring now to an aspect according to
The method 1000 may further comprise step 1002 for coupling each of the plurality of die to a respective one of the plurality of metallic pads, wherein the plurality of die comprises a first die and a second die. For example, step 1002 can include soldering or otherwise electrically coupling the first and second die to the metallic pads of the IMS board. According to other aspects, method 1000 may include a step for configuring the plurality of metallic pads to include four pads, each of which is electrically isolated from each other by, for example, being separated by a dielectric material that can be part of the thermally conductive dielectric layer of an IMS board, or a ceramic substrate. According to this aspect, the method may include configuring the first die to be coupled to the first pad, to the second pad, and the third pad all via wire bonding and/or any other electrical coupling, and then the second die can be coupled to the second pad and the fourth pad also via wire bonding or and/or any other electrical coupling. The pads may then be coupled to at least one of the circuit board's leads through welding them or soldering them together or otherwise electrically connecting them.
Method 1000 may further include a step 1003 for configuring the first die to exhibit a first bottom-side electrical potential and configuring the second die to exhibit a second bottom-side electrical potential based on coupling each of the plurality of die to a respective one of the plurality of metallic foil pads. The metallic pad coupled to the first die may be coupled to a first lead that is coupled to a first external source for generating the first bottom-side electrical potential, and the metallic pad coupled to the second die may be coupled to a second lead that is coupled to a second external source for generating the second bottom-side electrical potential. According to one aspect, the first bottom-side electrical potential of the first die and the second bottom-side electrical potential of the second die may have different values. The circuit board can conduct heat away from the plurality of die. For example, heat dissipates away from the first die and the second die via the metallic base plate, the thermally conductive dielectric, and the plurality of metallic pads. According to this aspect, for example, layers of the circuit board may be structured or arranged such that power dissipated from the first and second die may be thermally conducted from the die to the metallic pads, through the thermally conductive dielectric and then out of the circuit board through the metallic base plate and into an external heat sink.
According to other aspects, method 1000 may further comprise a step for configuring the leads to be coupled to a second apparatus and to at least one of the die by soldering or otherwise electrically coupling them. The method may also include a step for configuring a non-conductive housing, such as plastic, to at least partially enclose the circuit board. The method may further comprise a step for configuring the metallic base plate to be electrically isolated from the plurality of metallic pads, such as by including the dielectric material between them, and for making each of the metallic pads out of foil or other conducting material.
The non-conductive housing may be configured to at least partially enclose the circuit board. The non-conductive housing may be configured with a void between the circuit board's leads (e.g., a plurality of leads) and the metallic base plate. The void may artificially lengthen the surface distance between the circuit board's leads and the metallic baseplate to increase the creepage distance (distance along the surface between two conductive parts) between the leads and the metallic baseplate. The void causes increased voltage isolation and increased material choices for the non-conductive housing.
According to yet another aspect of the present disclosure, method 1000 may further include a step for configuring a heat sink to be coupled to the die and further configuring the circuit board to conduct heat away from the die to the heat sink. For example, the heat sink can be a device or substance for absorbing excessive or unwanted heat from the die that may be fan-cooled, liquid-cooled, cold plate, Peltier cooling device, or thermal heat pipes and may be made out of aluminum, copper, or other thermally conductive materials. According to another aspect, method 1000 may further include a step for configuring a third die to exhibit a third bottom-side electrical potential that may be different or the same as the first and second die's bottom-side potential. According to this aspect, the first die may be a custom IC or other semiconductor or electronic circuit that is soldered or otherwise electrically coupled to the pads. Also according to this aspect, the second die may be an NMOS transistor or any other type of transistor or electronic circuit, and the third die may be a PMOS transistor or any other type of transistor or electronic circuit.
While the methods and systems have been described in connection with preferred embodiments and specific examples, it is not intended that the scope be limited to the particular embodiments set forth, as the embodiments herein are intended in all respects to be illustrative rather than restrictive.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; the number or type of embodiments described in the specification.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims.
This application is a continuation-in-part application of U.S. application Ser. No. 16/425,063, filed May 29, 2019, which claims the benefit of priority of U.S. Provisional Application No. 62/677,519, filed May 29, 2018, the contents of which are herein incorporated by reference in their entirety.
Number | Date | Country | |
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62677519 | May 2018 | US |
Number | Date | Country | |
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Parent | 16425063 | May 2019 | US |
Child | 17179030 | US |