Semiconductor package with carrier support structure

Abstract

The invention relates to a semiconductor package with a carrier support structure. A method of forming a semiconductor package includes providing a lead frame including a plurality of leads connected to a peripheral structure; providing a plurality of tube core bonding pads, wherein each tube core bonding pad is provided with a power switch device; providing a first circuit carrier on which a controller device is mounted, the controller device being configured to control a switching operation of the power switching device; forming a mechanical connection between the first circuit carrier and the lead frame; and performing an encapsulation process to form an electrically insulating enclosure that encapsulates the power switching device and the controller device, where the first circuit carrier is physically supported by a mechanical connection prior to performing the encapsulation process, and where forming the mechanical connection includes an electrical interconnect process operation.

Description

Technical Field

[0001] This disclosure relates to semiconductor packaging with a carrier support structure. Background Technology

[0002] Many different applications, such as automotive and industrial applications, utilize power modules that include multiple power devices in a single package or housing. Power modules can include power conversion circuitry such as single-phase and multi-phase half-wave rectifiers, single-phase and multi-phase full-wave rectifiers, voltage regulators, inverters, etc. Modern power modules are designed to achieve minimal power loss and can improve the energy efficiency of power systems. Power modules can form part of power-efficient solutions to reduce or prevent anthropogenic greenhouse gas emissions. For example, hybrid electric vehicles (HEVs) or electric vehicles (EVs) utilize power modules to perform power conversion, inversion, switching, etc., in a power-efficient manner. Integrated power modules (IPMs), also known as intelligent power modules, include power electronics and logic circuitry for controlling the operation of the power electronics. The goal is to produce integrated power modules with lower cost and higher reliability. Summary of the Invention

[0003] Those skilled in the art will recognize the additional features and advantages after reading the following detailed description and reviewing the accompanying drawings.

[0004] A method for forming a semiconductor package is disclosed. According to one embodiment, the method includes: providing a lead frame including a plurality of leads connected to a peripheral structure; providing a plurality of die pads, each die pad mounting a power switching device; providing a first circuit carrier mounting a controller device configured to control switching operations of the power switching devices; forming a mechanical connection between the first circuit carrier and the lead frame; and performing an encapsulation process to form an electrically insulating encapsulation encapsulating the power switching devices and the controller device, wherein the first circuit carrier is physically supported by the mechanical connection prior to performing the encapsulation process, and wherein forming the mechanical connection includes electrical interconnection processing operations.

[0005] A semiconductor package is disclosed. According to one embodiment, the semiconductor package includes: a lead frame including a plurality of leads; a plurality of die pads, each die pad having a power switching device mounted thereon; a first circuit carrier having a controller device mounted thereon, the controller device being configured to control the switching operation of the power switching device; a mechanical connection to the first circuit carrier; and an electrically insulating encapsulation encapsulating the power switching device and the controller device, wherein the mechanical connection is non-electrically active, and wherein the mechanical connection includes one or more of an attachable metal element and a conductive adhesive. Attached Figure Description

[0006] The elements in the accompanying drawings are not necessarily drawn to scale relative to each other. The same reference numerals denote corresponding similar parts. Features of the various illustrated embodiments can be combined unless they are mutually exclusive. Embodiments are depicted in the accompanying drawings and described in detail below.

[0007] Figure 1 A component for forming a semiconductor package according to one embodiment is shown.

[0008] Figure 2 An encapsulation step for forming a semiconductor package is shown according to one embodiment.

[0009] Figure 3 A semiconductor package after encapsulation and lead trimming is shown according to one embodiment.

[0010] Figure 4A , Figure 4B , Figure 4C , Figure 4D and Figure 4E Various operations for forming a mechanical connection between a semiconductor package and a lead frame, according to one embodiment, are illustrated.

[0011] Figure 5 A component for forming a semiconductor package according to one embodiment is shown.

[0012] Figure 6 A component for forming a semiconductor package according to one embodiment is shown. Detailed Implementation

[0013] This document describes embodiments of semiconductor packaging and corresponding methods for forming semiconductor packages. The semiconductor package is configured as an integrated power module having power switching devices and controller devices, the controller devices being configured to control the switching of the power switching devices. The semiconductor package is formed from a packaging assembly having a dedicated circuit carrier that houses the controller devices and electrical interconnects for the controller devices. The semiconductor package is formed by an encapsulation process, whereby the lead frame and circuit carrier are placed within a mold injection tool. This operation requires physical support of the circuit carrier prior to the encapsulation process until the encapsulation material hardens. The embodiments disclosed herein advantageously utilize electrical interconnect processing operations to form a mechanical connection between the circuit carrier and the lead frame, thereby providing mechanical support for the circuit carrier before and during the encapsulation process. These electrical interconnect processing operations are the same operations commonly used to form electrical connections. As a result, no special processing steps and / or machining are required to create mechanical support between the circuit carrier and the lead frame. Furthermore, the electrical interconnect processing operations form stable mechanical connections with low cost and high reliability.

[0014] refer to Figure 1 This illustration shows an assembly 100 for forming a semiconductor package 200 according to one embodiment. The semiconductor package 200 includes a lead frame 102, which includes a plurality of leads 104 connected to a peripheral structure 106. The peripheral structure 106 forms a closed shape surrounding a central region of the lead frame 102. Each lead 104 extends away from the central region of the lead frame 102 and is connected to the peripheral structure 106. The lead frame 102 is formed of a conductive metal (e.g., copper, nickel, aluminum, palladium, gold, and alloys or combinations thereof). The lead frame 102 may be provided as a sheet of metal of substantially uniform thickness, and the geometry of the lead frame 102 may be produced by metal processing operations (e.g., stamping, punching, etching, etc.). The lead frame 102 may include a core metal region having one or more layers or coatings (e.g., an adhesion-promoting layer, an anti-corrosion layer, etc.).

[0015] Component 100 includes a plurality of die pads 108 for receiving power switching devices 110 mounted thereon. In the depicted embodiment, the plurality of die pads 108 are provided by a lead frame 102. That is, the lead frame 102 itself is used to receive the power switching devices 110 mounted thereon. The lead frame 102 is configured such that each die pad 108 is connected to a peripheral structure 106. Specifically, each die pad 108 is connected to one of leads 104, which in turn are connected to the peripheral structure 106. In the depicted embodiment, the connection between the die pads 108 and the leads 104 is provided by a recessed portion of the lead frame 102 that is vertically offset relative to the die pads 108 and the leads 104.

[0016] Power switching device 110 is a discrete transistor die rated to control large voltages and currents, such as at least 100V (volts), and more typically 600V, 1200V, or greater, and / or at least 1A of current, and more typically 10A, 50A, 100A, or greater. Examples of such devices include MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBTs (Insulated-Gate Bipolar Transistors), and HEMTs (High Electron Mobility Transistors). As shown, power switching device 110 is configured as a vertical device having a main surface and a rear surface, wherein the main surface includes a first load terminal 112 (e.g., source, drain, collector, emitter, etc.) and a gate terminal 114 facing away from the corresponding die pad 108, and the rear surface includes a second load terminal (e.g., one of the opposite of the source, drain, collector, emitter, etc.) facing the corresponding die pad 108. In a manner generally known, the power switching device 110 is configured to control the conductive connection between the first load terminal 112 and the second load terminal via the gate terminal 114.

[0017] Component 100 also includes a first circuit carrier 116 disposed within a central opening of the peripheral structure 106. The first circuit carrier 116 is a separate structure from the structure providing die pads 108 for accommodating power switching devices 110 mounted thereon. Generally, the first circuit carrier 116 can be any type of electronic carrier. According to one embodiment, the first circuit carrier 116 is a PCB.

[0018] A controller device 118 is mounted on a first circuit carrier 116. The controller device 118 is configured to control the switching operation of a power switching device 110. The controller device 118 may be a logic device. For example, the controller device 118 may be a silicon-based logic die. The controller device 118 may be a so-called surface mount device, wherein the leads of the controller device 118 are mounted on the first circuit carrier 116 and form a direct electrical connection with the first circuit carrier 116. Alternatively, the controller device 118 may be connected to the circuit carrier at its upper side using interconnecting elements (e.g., bond wires) connected to a circuit board, wherein the lower side of the controller device 118 is fixed, for example, using adhesive.

[0019] Component 100 includes the following electrical connections: A set of leads 104 are electrically connected to the input terminals of controller device 118. The output terminals of controller device 118 are electrically connected to the gate terminal 114 of power switching device 110. In each case, these electrical connections are achieved by conductive tracks and electrical interconnecting elements (e.g., bonding wires) in the first circuit carrier 116. The first load terminal 112 of power switching device 110 is electrically connected to a corresponding die pad, for example, by a conductive adhesive such as solder, sinter, etc. Each of the die pads 108 is in turn electrically connected to one of the leads 104 via a recessed portion of lead frame 102, as described above. The first load terminal 112 of power switching device 110 is electrically connected to a landing pad section of lead frame 102, which in turn is electrically connected to one of the leads 104. These electrical connections can be achieved by electrical interconnecting elements (e.g., bonding wires) as shown.

[0020] The semiconductor package 200 formed by component 100 (in) Figure 3 The image shown is a so-called Integrated Power Module (IPM), which refers to a type of package that includes both power electronic circuitry and logic circuitry for controlling the operation of the power electronic circuitry. Examples of power circuitry used in these modules include single-phase and multi-phase half-wave rectifiers, single-phase and multi-phase full-wave rectifiers, voltage regulators, etc. In the depicted embodiment, power switching device 110 is implemented in a half-bridge circuit configuration. A half-bridge circuit refers to a type of circuit topology used in power conversion circuits such as DC-to-DC converters, DC-to-AC converters, etc. The half-bridge circuit includes a high-side switch connected in series with a low-side switch. The control terminals (e.g., gate terminal 114) of the high-side and low-side switches can be switched by controller device 118 according to a power control scheme (e.g., pulse width modulation) to produce a desired voltage and frequency at the output of the half-bridge circuit. In the depicted embodiment, the leftmost three leads 104 connected to the first load terminals 112 of the three power switching devices 110 on the left side of the figure can be used to provide a fixed high voltage connection for the high-side switch, and the rightmost lead 104 connected to the second load terminals of the three power switching devices 110 on the right side of the figure can be used to provide a second fixed voltage connection for the low-side switch. The three central leads 104 between the leftmost three leads 104 and the rightmost lead 104 can form a phase connection of a half-bridge circuit. The three central leads 104 are each connected to the first load terminal 112 of one power switching device 110 and the second load terminal of another power switching device 110.

[0021] Prior to the encapsulation process, assembly 100, including lead frame 102 and first circuit carrier 116, can be mounted on a temporary carrier (such as a panel). The first circuit carrier 116 may initially have a controller device 118 mounted thereon. Alternatively, the first circuit carrier 116 may be mounted on a temporary carrier, and subsequently the controller device 118 may be mounted on the first circuit carrier 116. Power switching devices 110 may be mounted on each die pad 108. Mounting the power switching devices 110 may include providing a conductive adhesive, such as solder, between a second load terminal of the power switching device 110 and the die pad 108, and performing an annealing step, such as solder reflow, as needed. Electrical interconnects of the semiconductor package 200 can then be performed. Electrical interconnects can be formed by electrical interconnect processing operations (e.g., wire bonding, soldering, etc.). In the depicted embodiment, each electrical interconnect is implemented using a bonding wire. Alternatively, other types of electrical interconnect elements, such as metal clamps and strips, may be used.

[0022] refer to Figure 2 The diagram shows component 100 after an encapsulation process. The encapsulation process forms an electrically insulating encapsulation 202 encapsulating power switching device 110 and controller device 118. The encapsulation process may include injection molding or compression molding operations, wherein component 100 is disposed within the volume of a molding chamber, and a liquefied molding compound flows into the molding chamber and is subsequently cured by a curing process. Encapsulation materials may include molding compounds, epoxy resins, polyimides, etc.

[0023] refer to Figure 3 The figure illustrates a monolithic semiconductor package 200 according to one embodiment. A lead trimming process is performed to separate each of the leads 104 from the peripheral structure 106, for example by mechanical cutting, laser cutting, etching, etc., to produce the monolithic semiconductor package 200, thereby creating individual leads 104. Although the figures depict a single semiconductor package 200, multiple semiconductor packages 200 can be produced simultaneously, wherein the lead frame 102 represents a unit cell repeated multiple times.

[0024] Refer again Figure 1Component 100 includes a plurality of mechanical connections 120 between the first circuit carrier 116 and the peripheral structure 106. These mechanical connections 120 are used to hold the first circuit carrier 116 in position during the encapsulation process. More specifically, after die mounting and the formation of electrical interconnects, the semiconductor package 200 is transferred from a temporary carrier to a molding tool, thereby performing a molding process. At this time, the first circuit carrier 116 must be suspended in place until the encapsulation material (which forms the encapsulation body 202) is formed and hardened, at which point the encapsulated features are held in place by the encapsulation material. Prior to the encapsulation process, the first circuit carrier 116 is physically supported by the mechanical connections 120. At this time, the mechanical connections 120 can support substantially all the weight of the first circuit carrier 116. In the depicted embodiment, a bonding wire connection between a set of leads 104 electrically connected to the input terminals of the controller device 118 can provide a small degree of mechanical support. However, these bonding wires cannot support the full weight of the first circuit carrier 116, and therefore the mechanical connections 120 need to provide a considerable degree of mechanical support.

[0025] According to one embodiment, the mechanical connection 120 is formed via an electrical interconnection processing operation. As used herein, the term "electrical interconnection processing operation" refers to an operation for forming an electrical connection between components of a semiconductor package 200, such as an electrical connection between two bonding pads from, for example, a semiconductor device, a passive device, a circuit carrier, a lead frame, etc. Examples of electrical interconnection processing operations include operations for securing an attachable metal element between two conductive bonding pads, such as wire bonding, tape forming, clamp attachment, etc. Additional examples of electrical interconnection processing operations include operations for forming a conductive adhesive, such as soldering, sintering, gluing, etc.

[0026] According to one embodiment, at least some of the mechanical connections 120 are electrically inactive. That is, during operation of the semiconductor package 200, these mechanical connections 120 do not conduct any current and do not form signal connections. In this case, even if the mechanical connections 120 can be formed by electrical interconnection processing operations, the features forming the mechanical connections are electrically suspended. For this purpose, the first circuit carrier 116 may include electrically isolated bonding pads 122 disposed on the upper side of the first circuit carrier 116. These electrically isolated bonding pads 122 are isolated from other signal connections by insulating portions of the first circuit carrier 116.

[0027] In the depicted embodiment, some of the mechanical connections 120 are provided by mechanical support posts 124 connected to the peripheral structure 106 of the lead frame 102. According to one embodiment, the lead frame 102 includes mechanical support posts 124. That is, the mechanical support posts 124 form part of the lead frame 102 itself. The lead frame 102 is configured such that when the lead frame 102 is placed on a temporary carrier, the mechanical support posts 124 extend above the outer edge side of the first circuit carrier 116. The mechanical support posts 124 thus provide a surface through which the first circuit carrier 116 can be physically coupled to the peripheral structure 106 of the lead frame 102. The mechanical support posts 124 can be directly attached to the first circuit carrier 116 using electrical interconnection processing operations. As shown, the mechanical support posts 124 are directly attached to the first circuit carrier 116 via a bonding wire connection. Reference is made below. Figure 5 Various specific embodiments of the connection between the mechanical support post 124 and the first circuit carrier 116 are described in further detail. After encapsulation, the mechanical support post 124 may be trimmed, for example, in a manner similar to or with the lead trimming process, such that the outer side of the encapsulation 202 includes the outer surface, wherein the cut end of the mechanical support post 124 is coplanar or nearly coplanar with the outer surface.

[0028] In the depicted embodiment, some of the mechanical connections 120 are provided via direct connections between the die pads 108 from the lead frame 102 and the first circuit carrier 116. These direct connections are also provided using electrical interconnection processing operations. In the depicted embodiment, the mechanical connections 120 directly connecting the die pads 108 and the first circuit carrier 116 are provided via bonding wires. That is, the electrical interconnection processing operation for forming the mechanical connections 120 between the first circuit carrier 116 and the lead frame 102 is a wire bonding operation. These mechanical connections 120 between the die pads 108 from the lead frame 102 and the first circuit carrier 116 can be used to supplement the mechanical connections 120 provided by the mechanical support posts 124, thereby providing greater mechanical stability and distributing the weight of the first circuit carrier 116 across multiple support points.

[0029] In addition to the depicted embodiments, the mechanical connections 120 can be implemented in various ways using electrical interconnection processing operations. For example, instead of the mechanical support posts 124 formed as a dedicated part of the lead frame 102, individual interconnecting elements such as metal clamps can be attached to the peripheral structure 106, for example, by welding, soldering, etc. Alone or in combination, instead of bonding wires, different types of interconnecting elements such as metal clamps and strips can be used to form the mechanical connections 120. Alone or in combination, conductive adhesives can be used, either in place of or in combination with interconnecting elements, to form at least some of the mechanical connections 120.

[0030] According to one embodiment, at least some of the electrical interconnect processing operations used to form the mechanical connection 120 are performed as part of a common process also used to form the active electrical interconnects of the device. That is, the same processing tools and / or electrical interconnect elements can be used to perform a single processing step to form the active electrical interconnects and the mechanical connection 120. In one particular example, the mechanical connection 120 is formed by a wire bonding process, which is also used to form the active electrical interconnects of the device. In particular, the wire bonding process for the active electrical interconnects requires the thickest and therefore mechanically strongest bonding wires. For example, relatively thick bonding wires (e.g., bonding wires having a thickness of at least 50 μm, at least 100 μm, at least 150 μm, at least 200 μm, at least 250 μm, etc.) can be used to form the bonding wire connection between the first load terminal 112 of the power switching device 110 and the lead frame 102. For example, these bonding wires have a thickness between 200 μm and 300 μm; in one particular embodiment, these bonding wires have a thickness of, for example, 250 μm.

[0031] Generally, the number, location, and characteristics of the mechanical connections 120 formed by the electrical interconnection processing operations can be selected to meet the necessary structural requirements for supporting the first circuit carrier 116. For example, different numbers of mechanical support pillars 124 (e.g., three, four, six, eight, etc.) and corresponding connections can be used. Different numbers of electrical interconnection elements can be used individually or in combination.

[0032] refer to Figures 4A-4E Various embodiments of the electrical interconnection processing operations for forming the mechanical connection 120 are illustrated. In each case, a lead frame 102 including two mechanical support posts 124 is shown, extending above the outer edge of the first circuit carrier 116. For ease of illustration, other components of the assembly 100, including the peripheral structure 106 and the controller device 118, are omitted.

[0033] The first electrical interconnection processing operation for forming a mechanical connection Figure 4AAs shown in the figure. In the first step of this operation, a first circuit carrier 116 is provided, and a lead frame 102 is arranged such that a mechanical support post 124 extends above the outer edge side of the first circuit carrier 116. The lead frame 102 is configured such that there is a vertical offset between the upper surface of the first circuit carrier 116 and the mechanical support post, wherein there is a sufficient gap between them (e.g., between about 25 μm and 200 μm) to form a bonding wire connection. In the second step of this operation, a wire bonding process is performed to form a bonding wire between the upper side of the first circuit carrier 116 and the mechanical support post 124. The wire bonding process can be performed according to any of a variety of operations that utilize mechanical pressure and / or heat to form a strong mechanical connection. For example, the wire bonding process can include a wedge-wedge process, a wedge-ball process (as shown), etc.

[0034] The second electrical interconnection processing operation used to form a mechanical connection Figure 4B As shown in the diagram. In the first step of this operation, a first circuit carrier 116 is provided, and the lead frame 102 is arranged such that the mechanical support post 124 extends above the outer edge of the first circuit carrier 116 in a manner similar to that described above. In the second step of this operation, an attachment material is provided. The attachment material may include any material that forms an adhesive bond, such as solder, sinter, adhesive, etc. In the third step of this operation, an attachment process is performed to directly attach the first circuit carrier 116 to the mechanical support post 124 using the attachment material. Depending on the circumstances, the attachment process may include applying pressure, time, etc., to induce reflow, curing, etc. As a result, the attachment material forms a stable mechanical connection.

[0035] Third electrical interconnection processing operations used to form mechanical connections Figure 4C As shown in the diagram. In the first step of this operation, a first circuit carrier 116 is provided, and a lead frame 102 is arranged such that a mechanical support post 124 extends above the outer edge of the first circuit carrier 116 in a manner similar to that described above. In this case, the mechanical support post 124 includes perforations, i.e., openings through the thickness of the lead frame 102. The lead frame 102 is arranged such that these perforations extend above the upper side of the first circuit carrier 116. In the second step of this operation, a wire bonding process is performed to form a bonding wire between the upper side of the first circuit carrier 116 and the mechanical support post 124. In this case, the bonding wire extends through the perforation. In the third step of this operation, a conductive adhesive is provided within the perforation. The conductive adhesive provides additional mechanisms for attaching the bonding wire to the mechanical support post, thereby enhancing the mechanical strength of the connection.

[0036] The fourth electrical interconnection processing operation used to form mechanical connections Figure 4DAs shown in the diagram. In the first step of this operation, a vertical line is formed on the upper surface of the first circuit carrier 116. This vertical line can be a conductive post or other type of metal structure formed as a separate structure. In the second step of this operation, the lead frame 102 is arranged such that the mechanical support post 124 extends above the outer edge side of the first circuit carrier 116, and the vertical line extends through a perforation in the mechanical support post 124. In the third step of this operation, conductive adhesive is provided within the perforation. The conductive adhesive securely attaches the vertical line to the mechanical support post.

[0037] The fifth electrical interconnection processing operation used to form mechanical connections Figure 4E As shown in the diagram. In the first step of this operation, a first circuit carrier 116 is provided, and a lead frame 102 is arranged such that a mechanical support post 124 extends above the outer edge of the first circuit carrier 116. In this case, the mechanical support post 124 includes perforations. The lead frame 102 is arranged such that these perforations extend above the upper side of the first circuit carrier 116. In the second step of this operation, an attachment material is provided. In the third step of this operation, the attachment material is applied within the perforations, and an attachment process is performed to directly attach the first circuit carrier 116 to the mechanical support post using the attachment material. Depending on the circumstances, the attachment process may include applying pressure, time, etc., to induce backflow, curing, etc. As a result, the attachment material forms a stable mechanical connection.

[0038] refer to Figure 5 The image shows a component 100 for forming a semiconductor package 200 according to another embodiment. Figure 5 Component 100 and Figure 1 The components are the same, except that the mechanical support post 124 attached to the peripheral structure 106 is omitted. In this case, the mechanical connection between the circuit carrier and the lead frame 102 is provided by a direct connection (i.e., a non-electrically active bonding wire connection that serves only as a mechanical support) between the die pad 108 of the lead frame 102 and the first circuit carrier 116. Similar to the reference... Figure 1 The described embodiment can provide some additional mechanical support through a small bonding wire connected between the first circuit carrier 116 and a set of leads 104 providing input connections to the controller device 118. However, the bonding wire connected between the die pad 108 and the first circuit carrier 116 can be configured to physically support most of the mechanical load. The thickness and number of bonding wires can be selected to produce sufficient mechanical stability.

[0039] refer to Figure 6The figure illustrates an assembly 100 for forming a semiconductor package 200 according to another embodiment. In this case, the assembly 100 additionally includes a second circuit carrier 126 adjacent to and spaced apart from the first circuit carrier 116. A plurality of die pads 108 housing power switching devices 110 mounted thereon are provided by the second circuit carrier 126. That is, the second circuit carrier 126 replaces the die pad portion of the lead frame 102 from the previous embodiment. The second circuit carrier 126 may be a PCB or a power electronics carrier, such as a DCB substrate, a DAB substrate, or an AMB substrate, etc. As shown, Figure 6 The component 100 includes multiple pairs of power switching devices 110, each pair of power switching devices 110 being mounted adjacent to each other on a common die pad 108. Each pair of power switching devices 110 may correspond to the high-side switch and the low-side switch of a half-bridge circuit.

[0040] exist Figure 6 In this embodiment, each of the first circuit carrier 116 and the second circuit carrier 126 is mechanically connected to the peripheral structure 106 of the lead frame 102 via a mechanical connection 120 formed by an electrical interconnection process. Specifically, the mechanical connection between the second circuit carrier 126 and the lead frame 102 is provided by a set of bonding wires connected between the load terminals and output leads 104 of multiple pairs of power switching devices 110. This set of bonding wires also provides electrical connections between the leads 104 and the power switching devices 110, i.e., phase connections for each half-bridge circuit. The first circuit carrier 116 is physically supported by a set of bonding wires connected between the second circuit carrier 126 and the first circuit carrier 116. This set of bonding wires provides physical support through their connection to the second circuit carrier 126. The first circuit carrier 116 is physically coupled to the lead frame 102 via the second circuit carrier 126. As shown, the second circuit carrier 126 may include electrically isolated bonding pads 122 (which accommodate the bonding wires forming the mechanical connections), thereby keeping these connections non-electrically active.

[0041] The embodiments disclosed herein describe semiconductor devices, which may be referred to as semiconductor chips or semiconductor dies. These semiconductor devices may include any of a wide variety of semiconductor materials, including but not limited to elemental semiconductor materials such as silicon (Si) or germanium (Ge), group IV compound semiconductor materials such as silicon carbide (SiC) or silicon germanium (SiGe), and binary, ternary, or quaternary group III-V semiconductor materials such as gallium nitride (GaN), gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), indium gallium phosphide (InGaPa), aluminum gallium nitride (AlGaN), aluminum indium nitride (AlInN), and indium gallium nitride (InGaN). These semiconductor devices may have a wide variety of device configurations, including integrated device configurations and discrete device configurations. These semiconductor devices may be configured as vertical devices, meaning devices that conduct load current between opposing main and rear surfaces of the die. Alternatively, these semiconductor devices may be configured as lateral devices, meaning devices that conduct load current parallel to the main surface of the die.

[0042] As used herein, the term "circuit carrier" is intended to describe an electronic board configured to house electronic devices (e.g., semiconductor dies, passive devices, etc.) mounted thereon. A circuit carrier includes an electrically insulating substrate region and one or more metallization layers. The metallization layers may be structured as die pads 108, bonding pads, and conductive tracks to facilitate electrical interconnections between various devices mounted thereon and / or between devices mounted thereon and external devices. Examples of circuit carriers include PCBs (printed circuit boards) and power electronics carriers, such as DCB (direct copper bonding) substrates, DAB (direct aluminum bonding) substrates, and AMB (active metal bonding) substrates. In the case of a PCB, the electrically insulating substrate portion of the circuit carrier may include a laminate material, including prepreg materials (e.g., FR-4, FR-5, CEM-4, etc.) and resin materials (such as bismaleimide triazine (BT) resin). In the case of a power electronics carrier, the electrically insulating substrate portion of the circuit carrier may include ceramic materials such as Al2O3 (alumina), AlN (aluminum nitride), etc. In any example, one or more metallization layers of the circuit carrier may be formed of a conductive metal, such as copper (Cu), aluminum (Al), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), and their alloys or combinations.

[0043] As used herein, the term "electrical interconnect element" encompasses any conductive element that can be connected between two conductive regions to complete an electrical interconnection between them. Examples of electrical interconnect elements include bonding wires, tapes, and metal clamps. In any embodiment, each electrical connection may be provided by a single electrical interconnect element or by multiple electrical interconnect elements forming a parallel connection.

[0044] Terms such as "first," "second," etc., are used to describe various components, areas, parts, etc., and are not intended to be limiting. Throughout the specification, the same term refers to the same component.

[0045] As used herein, the terms “having,” “containing,” “including,” “comprising,” etc., are open-ended terms that indicate the presence of the stated element or feature but do not exclude additional elements or features. The articles “a,” “an,” and “the” are intended to include both plural and singular forms unless the context clearly indicates otherwise.

[0046] It should be understood that, unless otherwise specifically stated, the features of the various embodiments described herein can be combined with each other.

[0047] Although this disclosure is not limited thereto, the examples numbered below illustrate one or more aspects of this disclosure.

[0048] Example 1: A method of forming a semiconductor package, the method comprising: providing a lead frame including a plurality of leads connected to a peripheral structure; providing a plurality of die pads, each die pad having a power switching device mounted thereon; providing a first circuit carrier having a controller device mounted thereon, the controller device being configured to control switching operations of the power switching devices; forming a mechanical connection between the first circuit carrier and the lead frame; and performing an encapsulation process to form an electrically insulating encapsulation encapsulating the power switching devices and the controller device, wherein the first circuit carrier is physically supported by the mechanical connection prior to performing the encapsulation process, and wherein forming the mechanical connection includes an electrical interconnection processing operation.

[0049] Example 2: The method described in Example 1, wherein the mechanical connection is non-electrically active.

[0050] Example 3: According to the method of Example 1, wherein the first circuit carrier is a printed circuit board, and wherein the mechanical connection is fixed to an electrically isolated bonding pad disposed on the upper side of the first circuit carrier.

[0051] Example 4: According to the method of Example 1, wherein the electrical interconnection processing operation includes one or more of the following: attaching an attachable metal element to one or both of the first circuit carrier and the lead frame; and applying a conductive adhesive to one or both of the first circuit carrier and the lead frame.

[0052] Example 5: According to the method of Example 4, wherein the electrical interconnection processing operation includes securing the attachable metal element to one or both of the first circuit carrier and the lead frame, and wherein the attachable metal element is a bonding wire.

[0053] Example 6: According to the method of Example 4, wherein the electrical interconnection processing operation includes applying the conductive adhesive to one or both of the first circuit carrier and the lead frame, and wherein the conductive adhesive is a solder material.

[0054] Example 7: According to the method of Example 4, wherein the lead frame includes mechanical support posts, wherein the method includes arranging the mechanical support posts to extend above the outer edge side of the first circuit carrier, and wherein forming the mechanical connection includes directly attaching the mechanical support posts to the upper side of the first circuit carrier using the electrical interconnection processing operation.

[0055] Example 8: According to the method of Example 7, wherein directly attaching the mechanical support column to the upper side of the first circuit carrier includes attaching a bonding line to the upper side of the first circuit carrier and the mechanical support column.

[0056] Example 9: According to the method of Example 8, the method of directly attaching the mechanical support column to the upper side of the first circuit carrier further includes welding the bonding wire to the upper side of the first circuit carrier and the mechanical support column.

[0057] Example 10: According to the method of Example 7, the method of directly attaching the mechanical support column to the upper side of the first circuit carrier further includes applying a conductive adhesive between the upper side of the first circuit carrier and the mechanical support column.

[0058] Example 11: According to the method of Example 7, wherein the mechanical support column includes a perforation, and wherein the mechanical support column is arranged such that the perforation extends above the upper side of the first circuit carrier.

[0059] Example 12: According to the method of Example 11, forming the mechanical connection includes attaching a bonding wire to the upper side of the first circuit carrier and the mechanical support post, the bonding wire being wired through the perforation.

[0060] Example 13: According to the method of Example 11, forming the mechanical connection includes: forming a vertical line on the upper side of the first circuit carrier; arranging the vertical line within the perforation; and attaching the vertical line to the mechanical support column by means of a conductive adhesive.

[0061] Example 14: According to the method of Example 11, forming the mechanical connection includes providing a conductive adhesive within the perforation, the conductive adhesive directly attaching the mechanical support post to the first circuit carrier.

[0062] Example 15: According to the method of Example 1, wherein the plurality of die pads are provided by the lead frame, wherein the lead frame is configured such that each die pad in the die pads is connected to the peripheral structure.

[0063] Example 16: According to the method of Example 15, forming the mechanical connection between the first circuit carrier and the lead frame includes attaching at least some of the die pads in the die pads to the first circuit carrier using the electrical interconnection processing operation.

[0064] Example 17: According to the method of Example 1, wherein the plurality of die pads are provided by a second circuit carrier, wherein the method includes forming a second mechanical connection between the second circuit carrier and the lead frame.

[0065] Example 18: According to the method of Example 17, forming the mechanical connection between the first circuit carrier and the lead frame includes attaching the second circuit carrier to the first circuit carrier using the electrical interconnection processing operation.

[0066] Example 19: A semiconductor package comprising: a lead frame including a plurality of leads; a plurality of die pads, each die pad having a power switching device mounted thereon; a first circuit carrier having a controller device mounted thereon, the controller device being configured to control switching operation of the power switching device; a mechanical connection to the first circuit carrier; and an electrically insulating encapsulation encapsulating the power switching device and the controller device, wherein the mechanical connection is non-electrically active, and wherein the mechanical connection includes one or more of an attachable metal element and a conductive adhesive.

[0067] Example 20: A semiconductor package according to Example 19, wherein the first circuit carrier is a printed circuit board, and wherein the mechanical connection is fixed to an electrically isolated bonding pad disposed on the upper side of the first circuit carrier.

[0068] Example 21: A semiconductor package according to Example 19, wherein the lead frame further includes cleaved mechanical posts, and wherein the cleaved mechanical posts form part of the mechanical connection.

[0069] Example 22: A semiconductor package according to Example 21, wherein the attachable metal element is a junction line attached to the upper side of the first circuit carrier and the cut mechanical post.

[0070] Example 23: A semiconductor package according to Example 19, wherein the plurality of die pads are provided by the lead frame, and wherein at least some of the die pads are attached to the first circuit carrier via the mechanical connection.

[0071] Example 24: A semiconductor package according to Example 19, wherein the plurality of die pads are provided by a second circuit carrier, and wherein the second circuit carrier is attached to the first circuit carrier via the mechanical connection.

[0072] Although specific embodiments have been shown and described herein, those skilled in the art will understand that various alternatives and / or equivalent embodiments can be used instead of the shown and described embodiments without departing from the scope of the invention. This application is intended to cover any variations or modifications of the specific embodiments discussed herein. Therefore, the invention is intended to be limited only by the claims and their equivalents.

Claims

1. A method for forming a semiconductor package, comprising: A lead frame is provided, the lead frame including multiple leads connected to an external structure; Multiple die pads are provided, and each die pad is equipped with a power switching device; A first circuit carrier is provided, on which a controller device is mounted, the controller device being configured to control the switching operation of the power switching device; A mechanical connection is formed between the first circuit carrier and the lead frame; as well as An encapsulation process is performed to form an electrically insulating encapsulation for the power switching device and the controller device. Wherein, the first circuit carrier is physically supported by the mechanical connection before the encapsulation process is performed, and The formation of the mechanical connection includes electrical interconnection processing operations.

2. The method according to claim 1, wherein, The mechanical connection is non-electrically active.

3. The method according to claim 1, wherein, The first circuit carrier is a printed circuit board, and the mechanical connection is fixed to an electrically isolated bonding pad disposed on the upper side of the first circuit carrier.

4. The method according to claim 1, wherein, The electrical interconnection processing operation includes one or more of the following: Attachable metal components to one or both of the first circuit carrier and the lead frame; and A conductive adhesive is applied to one or both of the first circuit carrier and the lead frame.

5. The method according to claim 4, wherein, The electrical interconnection process includes attaching the attachable metal element to one or both of the first circuit carrier and the lead frame, wherein the attachable metal element is a bonding wire.

6. The method according to claim 4, wherein, The electrical interconnection process includes applying the conductive adhesive to one or both of the first circuit carrier and the lead frame, wherein the conductive adhesive is a solder material.

7. The method according to claim 4, wherein, The lead frame includes mechanical support posts, wherein the method includes arranging the mechanical support posts to extend above the outer edge side of the first circuit carrier, and wherein forming the mechanical connection includes directly attaching the mechanical support posts to the upper side of the first circuit carrier using the electrical interconnection processing operation.

8. The method according to claim 7, wherein, Attaching the mechanical support column directly to the upper side of the first circuit carrier includes attaching a bonding line to the upper side of the first circuit carrier and the mechanical support column.

9. The method according to claim 8, wherein, Attaching the mechanical support column directly to the upper side of the first circuit carrier also includes welding the bonding wire to the upper side of the first circuit carrier and the mechanical support column.

10. The method according to claim 7, wherein, Attaching the mechanical support column directly to the upper side of the first circuit carrier also includes applying a conductive adhesive between the upper side of the first circuit carrier and the mechanical support column.

11. The method according to claim 7, wherein, The mechanical support column includes a perforation, and wherein the mechanical support column is arranged such that the perforation extends above the upper side of the first circuit carrier.

12. The method according to claim 11, wherein, Forming the mechanical connection includes attaching a bonding wire to the upper side of the first circuit carrier and the mechanical support post, the bonding wire being wired through the perforation.

13. The method according to claim 11, wherein, Forming the mechanical connection includes: A vertical line is formed on the upper side of the first circuit carrier; Arrange the vertical line within the perforation; and The vertical line is attached to the mechanical support column using a conductive adhesive.

14. The method according to claim 11, wherein, Forming the mechanical connection includes providing a conductive adhesive within the perforation, the conductive adhesive directly attaching the mechanical support post to the first circuit carrier.

15. The method according to claim 1, wherein, The plurality of die pads are provided by the lead frame, wherein the lead frame is configured such that each die pad in the die pads is connected to the peripheral structure.

16. The method according to claim 15, wherein, Forming the mechanical connection between the first circuit carrier and the lead frame includes attaching at least some of the die pads to the first circuit carrier using the electrical interconnection processing operation.

17. The method according to claim 1, wherein, The plurality of die pads are provided by a second circuit carrier, wherein the method includes forming a second mechanical connection between the second circuit carrier and the lead frame.

18. The method according to claim 17, wherein, Forming the mechanical connection between the first circuit carrier and the lead frame includes attaching the second circuit carrier to the first circuit carrier using the electrical interconnection processing operation.

19. A semiconductor package, comprising: A lead frame, the lead frame comprising a plurality of leads; Multiple die pads, each with a power switching device mounted on it; A first circuit carrier, on which a controller device is mounted, the controller device being configured to control the switching operation of the power switching device; Mechanical connection with the first circuit carrier; as well as An electrically insulating enclosure that encapsulates the power switching device and the controller device. The mechanical connection is non-electrically active, and The mechanical connection includes one or more of an attachable metal element and a conductive adhesive.

20. The semiconductor package of claim 19, wherein, The first circuit carrier is a printed circuit board, and the mechanical connection is fixed to an electrically isolated bonding pad disposed on the upper side of the first circuit carrier.

21. The semiconductor package of claim 19, wherein, The lead frame also includes a cut mechanical post, wherein the cut mechanical post forms part of the mechanical connection.

22. The semiconductor package of claim 21, wherein, The attachable metal element is attached to the upper side of the first circuit carrier and the junction line of the cut mechanical post.

23. The semiconductor package of claim 19, wherein, The plurality of die pads are provided by the lead frame, and wherein at least some of the die pads are attached to the first circuit carrier via the mechanical connection.

24. The semiconductor package of claim 19, wherein, The plurality of die pads are provided by a second circuit carrier, wherein the second circuit carrier is attached to the first circuit carrier via the mechanical connection.

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