Package with recesses for balancing creepage current paths

Abstract

The invention discloses a packaging body. Comprising a carrier, an electronic component mounted on the carrier, an encapsulation material completely encapsulating the electronic component and the carrier, conductive leads electrically coupled with the carrier and / or with the electronic component and extending from the encapsulation material at opposite sides of the encapsulation material, and a recess extending in at least one of the two opposite major surfaces of the encapsulation material and between the two opposite further sides of the encapsulation material, creepage current path length from one lead extending from the encapsulation material at one of the two opposite sides along one of the main surfaces and the recess to the other lead extending from the encapsulation material at the other of the two opposite sides and from the lead along the other of the main surfaces A difference between the other creepage current path length of the other lead does not exceed 20% of the creepage current path length.

Description

Technical Field

[0001] Various embodiments are generally directed to a package and a method of manufacturing a package. Background Art

[0002] A conventional package may include electronic components mounted on a chip carrier, may be electrically connected via connecting wires extending from the chip to the chip carrier or leads, and may be molded using a molding compound as an encapsulation material.

[0003] Electrical reliability of conventional packages can be an issue. Summary of the invention

[0004] A package having high electrical reliability and reasonable or low manufacturing effort may be desired.

[0005] According to an exemplary embodiment, a package is provided, comprising: a carrier, electronic components mounted on the carrier, an encapsulating material that completely encapsulates the electronic components and the carrier, conductive leads electrically coupled to the carrier and / or to the electronic components and extending from the encapsulating material at opposite sides of the encapsulating material, and a recess extending in at least one of two opposite main surfaces of the encapsulating material and between two other opposite sides of the encapsulating material, wherein a difference between a creepage current path length from one lead extending from the encapsulating material at one of the two opposite sides along one of the main surfaces and the recess to another lead extending from the encapsulating material at the other of the two opposite sides and a creepage current path length from the lead along the other of the main surfaces to the other lead does not exceed 20% of the creepage current path length.

[0006] According to another exemplary embodiment, a method for manufacturing a package is provided, the method comprising: mounting an electronic component on a carrier; completely encapsulating the electronic component and the carrier by an encapsulation material; electrically coupling a conductive lead to the carrier and / or to the electronic component, wherein the lead extends from the encapsulation material at two opposite sides of the encapsulation material; and forming a recess in at least one of two opposite main surfaces of the encapsulation material, the recess extending between two other opposite sides of the encapsulation material, wherein a difference between a creepage current path length of one lead extending from the encapsulation material at one of the two opposite sides along one of the main surfaces and the recess to another lead extending from the encapsulation material at the other of the two opposite sides and a creepage current path length from the lead along the other of the main surfaces to the other lead does not exceed 20% of the creepage current path length.

[0007] According to an exemplary embodiment, a package includes a carrier carrying an electronic component, wherein an encapsulating material completely encapsulates the electronic component and the carrier. In addition, leads extending to the outside of the encapsulating material at two opposite sides are electrically coupled to the carrier and / or the electronic component. One of the two opposite main surfaces of the encapsulating material or at least one recess in the two main surfaces extends completely or partially between two other opposite sides of the encapsulating material, wherein the side and the other side may be angled relative to each other. Advantageously, the difference between the creepage current path length of one lead extending from the encapsulating material at one of the two opposite sides along one of the main surfaces and the recess to another lead extending from the encapsulating material at the other of the two opposite sides and the other creepage current path length from the lead along the other of the main surfaces to the other lead does not exceed 20% of the creepage current path length. In short, the shape and size of the recess can be designed so that the minimum path lengths of the parasitic creepage current flowing between the opposite leads along the top side and the bottom side of the package, respectively, can differ from each other by a maximum of ±20%. Therefore, the creepage distances along the two opposite main surfaces of the package can be largely or even completely balanced by appropriate recess design, so that substantially uniform electrical performance can be obtained over the entire package extension scale. Advantageously, high electrical reliability can be obtained without undesirably increasing the package size. In particular, electrical weaknesses in terms of electrical reliability can be avoided. Therefore, the package can be designed for high voltage levels, such as at least 1200V. In addition to the effect of balancing and increasing the creepage current path length, the recess can also make the creepage current trajectory between the two opposite leads more complicated, which can further contribute to suppressing the creepage current.

[0008] Description of Further Exemplary Embodiments

[0009] In the following, further exemplary embodiments of the package and the method will be explained.

[0010] In the context of the present application, the term "package" may particularly denote an electronic device that may include one or more electronic components mounted on a (particularly conductive) carrier. The components of the package may be encapsulated by an encapsulation material. Optionally, one or more conductive interconnects (e.g. metal pillars, bumps, connecting wires and / or clips) may be implemented in the package, e.g. for electrically coupling and / or mechanically supporting the electronic components.

[0011] In the context of the present application, the term "carrier" may particularly refer to a support structure (which may be at least partially conductive) that serves as a mechanical support for (one or more) electronic components to be mounted thereon, and the support structure may also facilitate electrical interconnection between the (one or more) electronic components and the periphery of the package. In other words, the carrier may implement a mechanical support function and an electrical connection function. The carrier may include or consist of a single component, a plurality of components bonded via an encapsulation or other package components, or a subassembly of the carrier. When the carrier forms part of a lead frame, the carrier may be or may include a die pad. For example, such a carrier may be a lead frame plus structure (e.g., made of copper), a DAB (Direct Aluminum Bonding) substrate, a DCB (Direct Copper Bonding) substrate, etc. In addition, the carrier may also be configured as an active metal brazing (AMB: Active Metal Brazing) substrate.

[0012] In the context of the present application, the term "electronic component" may particularly include semiconductor chips (particularly power semiconductor chips), active electronic devices (such as transistors), passive electronic devices (such as capacitors or inductors or ohmic resistors), sensors (such as microphones, light sensors or gas sensors), actuators (such as speakers) and micro-electromechanical systems (MEMS). When the electronic component is a power device, it may be, for example, a switch, a gate driver or a functional combination (such as an intelligent power module (IPM: Intelligent Power Module) or an intelligent intelligent power module (intelligent IPM)). However, in other embodiments, the electronic component may also be of different types, such as electromechanical components, in particular mechanical switches, etc. In particular, the electronic component may be a semiconductor chip having at least one integrated circuit element (such as a diode or a transistor) in its surface portion. The electronic component may be a bare die or may have been packaged or encapsulated. The semiconductor chip implemented according to the exemplary embodiment may be formed in silicon technology, silicon on insulator (SOI) technology, gallium nitride technology, silicon carbide technology, etc.

[0013] In the context of the present application, the term "encapsulation material" may particularly refer to a substantially electrically insulating material surrounding an electronic component and a carrier to provide mechanical protection, electrical insulation and optionally to help dissipate heat during operation. In particular, the encapsulation material may be a molding compound. The molding compound may include a matrix of a flowable and hardenable material and filler particles embedded therein. For example, filler particles may be used to adjust the properties of the molded component, in particular to enhance thermal conductivity. As an alternative to a molding compound (e.g., based on epoxy resin), the encapsulation material may also be a potting compound (e.g., based on silicone gel).

[0014] In the context of the present application, the term "main surface" of the encapsulating material may particularly denote an encapsulating material surface of one of the largest encapsulating material surfaces, more particularly an encapsulating material surface of one of the two largest encapsulating material surfaces. For example, the encapsulating material may have two opposite main surfaces, which are separated in thickness direction by the material of the encapsulating material, the carrier and the electronic component and are connected to each other by a peripheral edge defined by a plurality of sides.

[0015] In the context of the present application, the term "side" of the encapsulating material may particularly denote a sidewall segment of the encapsulating material, which may define a periphery of the encapsulating material between its opposite main surfaces. The side may be oriented in a curved, inclined or orthogonal manner relative to the corresponding main surface. In particular, four sides of the encapsulating material may be defined, which may be divided into two groups of two opposite sides.

[0016] In the context of the present application, the term "lead" may particularly denote an electrically conductive, particularly metallic, elongated structure that extends partially into the interior of the encapsulating material and partially into the exterior of the encapsulating material for establishing an electrical connection between the encapsulated electronic component and the exterior of the package. Preferably, two leads or even two groups of leads may extend from two opposite sides of the encapsulating material, while the remaining two other opposite sides of the package may be free of leads. For example, the leads may be straight or curved (e.g., in a gull-wing shape).

[0017] In the context of the present application, the term "recess" may particularly refer to any notch, channel, groove, blind hole, groove and / or cavity extending along a partial distance between two opposite sides of the encapsulating material or preferably along the entire distance between two opposite sides of the encapsulating material in the main surface of the encapsulating material. The recess may also be formed between two parallel ridges. It is also possible to form a plurality of recesses in such a main surface, or to form one or more recesses in each of the two opposite main surfaces of the encapsulating material. Descriptively speaking, such a recess may be used to extend the creepage current path length between two opposite leads along the main surface of the encapsulating material, because the creepage current must flow along the entire path between the leads, including the additional surface portion increased by the recess. In addition to at least one recess, the corresponding main surface of the encapsulating material may optionally include at least one protrusion, which may additionally contribute to extending the creepage current path length. The main surface without a recess may also include at least one protrusion. In addition, the main surface of the encapsulating material may also be completely flat.

[0018] In the context of the present application, the term "creepage current path length between two leads along a main surface of the encapsulation material" may particularly denote the minimum length of a path along which a creepage current must flow on the surface of the encapsulation material to bridge the entire spatial extent between two opposing leads on two opposite sides of the encapsulation material. When a recess is formed in one main surface of the encapsulation material, the creepage current path length along the main surface includes an additional section defined by the surface trace of the recess.

[0019] In the context of the present application, the term "the difference between a creepage current path length (A) from a lead extending from the encapsulation material at one of the two opposite sides along one of the main surfaces and the recess to another lead extending from the encapsulation material at the other of the two opposite sides and another creepage current path length (B) from the lead along the other of the main surfaces to the other lead does not exceed 20% of the creepage current path length (A)" may specifically mean that the ratio between the absolute value of AB and A does not exceed 0.2.

[0020] In one embodiment, the sidewalls at two opposite sides of the encapsulation material are at least partially curved.The surface contour of the sidewalls, at which the leads extend out of the encapsulation material, may be defined by an encapsulation tool such as a molding tool.

[0021] In one embodiment, the exposed surface of the sidewall of the encapsulating material at two opposite sides has a protrusion formed by filler particles covered with a molded skin. For example, the encapsulating material can be a molding compound comprising a molded matrix material (e.g., including epoxy resin) filled with filler particles (e.g., for adjusting the thermal properties of the encapsulating material). When the shape of the sidewall is defined by a molding tool, the appearance of the sidewall can show a portion of the molded matrix material and a portion of the filler particles coated with a thin layer of the molded matrix material. Therefore, this surface configuration of the sidewall can be a unique point that the sidewall is defined by a molding tool.

[0022] In one embodiment, the sidewalls at the two opposite other sides of the encapsulation material are vertical. The two opposite other sides that may not have leads can be formed and defined by cutting, such as mechanical cutting or laser cutting. Therefore, the other sidewalls can be flat vertical surface portions of the encapsulation material. Defining the other sidewalls by cutting can simplify the manufacturing process. In addition, the recess defined by the curved surface can also be present at the outer surface of the other side and can be produced by previous filler particles removed from the molding matrix material by cutting, in particular by mechanical cutting.

[0023] In one embodiment, the exposed surface of the sidewall of the two opposite other sides of the encapsulating material has at least one of the following: a protrusion formed by exposed filler particles, a notch defined by a curved surface, a cut filler particle flush with the molded matrix material of the encapsulating material, and a heat-affected feature (e.g., carbide, carbon black, etc.). In particular, the protrusion formed by the exposed filler particles can be produced by laser cutting (e.g., using a nanosecond laser), when the laser beam burns the molded matrix material while keeping the external filler particles intact. Additionally or alternatively, the external surface of the other side of the encapsulating material can include cut filler particles flush with the molded matrix material of the encapsulating material. When a sharp mechanical cutting blade or a femtosecond laser cuts through the encapsulating material, a portion of the filler particles can also be cut off so that a flat external surface portion can be retained, which is partially defined by the molded matrix material and partially defined by the cut filler particles. In addition, a heat-affected feature can be present at a corresponding one of the other sides, such as a carbide generated by a laser beam when interacting with the material of the encapsulating material.

[0024] In one embodiment, the package is configured as a tie-bar-less package. In a favorable embodiment, no tie-bars may be present at all in the package, or no tie-bars may extend to the outer surface of the package. Thus, the outline of the package may be free of tie-bars. Tie-bars may be used to interconnect components of different packages during manufacturing. In many cases, the tie-bars are made of metal and may, for example, form part of a lead frame. The tie-bars may also be separated during separation of individual packages manufactured in a batch procedure. However, cutting through the metal tie-bar material may be cumbersome and may slow down the separation process. According to an exemplary embodiment, tie-bars may be omitted entirely, or at least in the areas where the packages are singulated by cutting.

[0025] In one embodiment, the recess is formed in the main surface of the encapsulating material facing the carrier and away from the electronic component. This design can increase the distance between the outer surface of the encapsulating material and the electronic component to protect the electronic component. Additionally or alternatively, the recess can be formed in the main surface of the encapsulating material away from the carrier and facing the electronic component.

[0026] In one embodiment, the package comprises a further recess in at least one of the two opposite main surfaces of the encapsulation material and extending between two other opposite sides of the encapsulation material. By providing a plurality of recesses in one or both of the main surfaces of the encapsulation material, the extension and balance of the creepage current path length can be further improved.

[0027] In one embodiment, the further recess is formed in the same main surface as the recess and extends parallel to the recess. Thus, multiple recesses can be formed in the same main surface of the encapsulation material, thereby significantly increasing the creepage current path length on this side of the encapsulation material, for example to balance the large difference in creepage current path length between the two main surfaces. For example, multiple recesses can be formed parallel to each other on the same main surface to require the creepage current to flow along a wave path for bridging the entire space between the two opposing leads. This can provide exceptionally reliable protection against undesired creepage currents.

[0028] In another embodiment, the further recess and the recess are formed in two opposite main surfaces of the encapsulation material and extend parallel to each other. Also in this configuration, the recess and the further recess can be configured to be able to adjust the above-mentioned difference between the creepage current path lengths to no more than 20% of the creepage current path length along one main surface of the encapsulation material. In addition, providing a corresponding recess on each of the two opposite main surfaces can make each corresponding creepage current path more complicated, thereby strongly suppressing the flow of creepage current between opposite leads along the two main surfaces. This can additionally improve the electrical reliability of the package.

[0029] In one embodiment, the lead is separated from the recess by a ridge of the encapsulation material, the ridge laterally delimiting the recess. When the recess extending along the entire distance between two other sides is formed in the central portion of the main surface of the encapsulation material, two ridges are formed between the sides and the recess. Descriptively speaking, such a ridge can make the creepage current flow more complicated between the leads on the two sides, which can further improve electrical reliability.

[0030] In one embodiment, at least the portion of the lead extending outside the encapsulation material is bent at least partially toward the major surface of the encapsulation material in which the recess is formed. For example, such a bent lead may be a gull-wing lead. The major surface of the package toward which the lead is bent may be more susceptible to creepage currents, so that forming a recess on the corresponding side of the encapsulation material may be preferred.

[0031] In one embodiment, the recess extends along the entire distance between two opposite further sides of the encapsulation material, i.e. from one further side all the way to the other further side. Thus, the entire lateral extent of the main surface having such a recess can be protected from creepage currents, since creepage currents cannot flow around the recess in this configuration.

[0032] In one embodiment, the recess is a groove, for example a straight groove. Such a groove may be an elongated notch, which preferably extends straight (alternatively curved, zigzag, meandering or wavy) and preferably extends along the entire extension between the further sides (alternatively only along a sub-portion). As described with reference to Figure 7 As described, such a groove can be produced in a very simple manner by a batch molding process.

[0033] In one embodiment, the ratio between the width and the depth of the recess is at least 2, such as at least 5. Thus, the recess may be wide and shallow. The length of the recess between the further sides may be greater than both the width and the depth.

[0034] In one embodiment, the difference does not exceed 10% of the creepage current path length. When the difference is a maximum of 10% or preferably a maximum of 5%, the creepage current flow characteristics along different main surfaces of the package can be almost completely balanced or equalized, thereby providing excellent electrical reliability. In a particularly preferred embodiment, the difference is zero or at least less than 1%.

[0035] In one embodiment, the vertical distance between the outer surface of the encapsulation material defined by the recess and the facing surface of the carrier is less than 400 μm, in particular in the range of 100 μm to 300 μm. As a result, the remaining isolation thickness of the encapsulation material (in particular the molding compound) below the carrier (e.g. the die pad) can be very small, thereby enabling a compact design of the package without compromising electrical reliability. By forming the encapsulation material of the respective package as part of a common strip-shaped encapsulation material body formed together for a plurality of packages, the thickness can be reduced compared to conventional methods without the risk of isolation failure. This is due to the fact that the molding flow is parallel to the recess, which allows even tiny spaces between the recess-defined molding tool and the bottom of the carrier to be reliably filled.

[0036] In one embodiment, the method includes supplying a material of a flowable encapsulating material for forming the encapsulating material along a direction corresponding to the extension dimension of the recess. When a liquid or viscous molding compound (or a material of another encapsulating material) is conveyed along a direction corresponding to the extension dimension of the recess, it is possible to reliably ensure that a creepage path extension ridge is formed laterally delimiting the recess, and that an encapsulating material isolation portion is formed under the carrier. This improves the electrical performance of the package and its overall reliability. In addition, this manufacturing process is fully compatible with the simultaneous batch formation of multiple packages based on a common encapsulating material structure, as described in further detail below. Therefore, the described measures can also improve the efficiency and yield of the package manufacturing.

[0037] In one embodiment, the method includes forming the package together with another package in a batch manufacturing process, the batch manufacturing process including: mounting a plurality of electronic components on a plurality of carriers of a common carrier structure; completely encapsulating the electronic components and the carriers by a plurality of encapsulating materials of a common strip-shaped encapsulating material structure; electrically coupling a plurality of conductive leads of a common lead structure to the carrier and / or to the electronic components, such that the lead structure extends from the encapsulating material structure at two opposite sides; and forming a plurality of recesses of a common recess structure in at least one of two opposite main surfaces of the encapsulating material structure, such that the common recess structure extends between two opposite other sides of the encapsulating material structure. Reference will be made below to Figures 5 to 7This very advantageous manufacturing process is described in more detail. In short, a plurality of electronic components can be assembled on a matrix-like arrangement structure of a carrier and can be electrically coupled to designated leads of a common lead structure. Thereafter, a pair of component carriers of a common row can be covered by a common strip-shaped encapsulation material structure, for example by molding. A plurality of parallel common strip-shaped encapsulation material structures can be formed simultaneously. Therefore, the encapsulation process can be performed on a plurality of rows simultaneously. During encapsulation, a common recess structure can be formed, with at least one common recess structure per row, thereby forming the recess described above for each package by the corresponding shape of the encapsulation tool. Thereafter, the individual packages can be separated by a separation process performed along rows and columns.

[0038] In one embodiment, the method comprises separating the packages by breaking, for example by punching, the leads of the common lead structure located outside the common encapsulating material structure. The breaking may be performed in the same direction as the direction in which the strip-shaped encapsulating material structure is formed. Preferably, punching through other components of the package, other than the leads, is not required.

[0039] In one embodiment, the method comprises separating the packages by breaking (e.g. by cutting, in particular mechanical cutting and / or laser cutting) the common encapsulating material structure along a separation direction corresponding to the extension direction of the leads. The further breaking may be performed along a direction perpendicular to another direction along which the strip-shaped encapsulating material structure is formed. Preferably, the separation process is performed without cutting through the metal tie bars, i.e. preferably only cutting through the material of the encapsulating material, which may accelerate the separation.

[0040] The combination of the two separation processes mentioned above allows for a fast, simple and precise separation of the individual packages.

[0041] In one embodiment, the package is configured as a power package. A power package may be a package that includes at least one power chip as an encapsulated electronic component. Thus, the package may be configured as a power module, such as a molded power module such as a semiconductor power package. For example, an exemplary embodiment of the package may be an intelligent power module (IPM). Intelligent IPMs are also possible (including microcontrollers). The package may also provide connectivity features such as WiFi, Bluetooth, etc. Another exemplary embodiment of the package is a dual inline package (DIP: Dual Inline Package).

[0042] Accordingly, the electronic component can be configured as a power semiconductor chip. Therefore, the electronic component (e.g., semiconductor chip) can be used for power applications in, for example, the automotive field, and can, for example, have at least one integrated insulated gate bipolar transistor (IGBT) and / or at least one transistor of another type (e.g., MOSFET, JFET, HEMT, etc.) and / or at least one integrated diode. Such an integrated circuit element can be manufactured, for example, with silicon technology or based on wide bandgap semiconductors (e.g., silicon carbide, gallium nitride). The semiconductor power chip may include one or more field effect transistors, diodes, inverter circuits, half bridges, full bridges, drivers, logic circuits, other devices, etc. The advantages of the exemplary embodiment regarding isolation are particularly evident for power bare chips. In addition, in the context of driver technologies (e.g., insulated gate drivers, level shifter gate drivers, solid-state relays, circuit breakers, etc.) that manipulate high voltages, exemplary embodiments can provide significant advantages.

[0043] In one embodiment, the carrier comprises a lead frame type die pad. The lead frame may be a metal structure inside the package that transmits signals from the electronic component to the outside and / or in the opposite direction. The lead frame may include a central die pad on which the electronic component is placed, the central die pad being surrounded by leads, i.e., electronic transmission portions from the electronic component to the package and / or metal conductors in the opposite direction.

[0044] In one embodiment, the encapsulation material encapsulates the electronic component and the carrier so that neither the front side nor the back side is exposed to the outside of the encapsulation material. Therefore, the package can have an outline defined only by the encapsulation material and one or more leads extending from the encapsulation material for electrical connection of the at least one encapsulated electronic component. Due to the circumferential dielectric encapsulation material of the package, such a package can have excellent electrical reliability.

[0045] In one embodiment, the package comprises a conductive coupling element electrically coupling the electronic component to the carrier and / or to at least one lead. Such conductive coupling element may be a clip, a connecting wire, a connecting strip and / or a flip chip interconnection element. The clip may be a bent electrical conductor that enables an electrical connection to the upper main surface of the corresponding electronic component with a high connection area. In addition to or as an alternative to such a clip, one or more other conductive interconnects may be implemented in the package, such as connecting wires and / or connecting strips that connect the electronic component to the carrier and / or leads or to different pads of the electronic component.

[0046] As a substrate or wafer forming the basis of the electronic component, a semiconductor substrate, in particular a silicon substrate, may be used. Alternatively, a silicon oxide or another insulator substrate may be provided. A germanium substrate or a III-V semiconductor material may also be implemented. For example, exemplary embodiments may be implemented in GaN or SiC technology.

[0047] The above and other objects, features and advantages will become apparent from the following description and appended claims taken in conjunction with the accompanying drawings in which like parts or elements are designated by like reference numerals. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which are included to provide a further understanding of exemplary embodiments and constitute a part of this specification, illustrate exemplary embodiments.

[0049] In the attached picture:

[0050] Figure 1 A cross-sectional view of a package according to an exemplary embodiment is shown.

[0051] Figure 2 A flow chart of a method of manufacturing a package according to an exemplary embodiment is shown.

[0052] Figure 3 A side view of a package according to an exemplary embodiment is shown.

[0053] Figure 4 Shown according to Figure 3 3D views and detailed drawings of the package.

[0054] Figure 5 A three-dimensional view of a structure for manufacturing a package according to an exemplary embodiment is shown.

[0055] Figure 6 A three-dimensional view of a structure for manufacturing a package according to an exemplary embodiment is shown.

[0056] Figure 7 A top view of a structure obtained during the manufacture of a package according to an exemplary embodiment is shown.

[0057] Figure 8 A cross-sectional view of a package according to another exemplary embodiment is shown.

[0058] Fig. 9 A cross-sectional view of a package according to yet another exemplary embodiment is shown.

[0059] Fig.10 A cross-sectional view of a package according to yet another exemplary embodiment is shown.

[0060] Fig.11 A cross-sectional view of a side wall of a package according to another exemplary embodiment is shown.

[0061] Fig.12 A cross-sectional view of a side wall of a package according to yet another exemplary embodiment is shown.

[0062] Fig.13 A cross-sectional view of a side wall of a package according to yet another exemplary embodiment is shown.

[0063] Fig.14 A top view of a structure obtained during the manufacture of a package according to another exemplary embodiment is shown. DETAILED DESCRIPTION

[0064] The illustrations in the drawings are schematic and not to scale.

[0065] Before the exemplary embodiments will be described in more detail with reference to the accompanying drawings, some general considerations will be outlined based on the exemplary embodiments that have been developed.

[0066] The technology for manufacturing leaded packages is moving into the ultra-high density realm. One reason for this is the goal of maximizing material utilization and increasing manufacturing flexibility. Further reductions in manufacturing effort can involve using encapsulation materials with higher creepage resistance.

[0067] At the same time, power semiconductors are being deployed to increase application voltages and meet increasingly challenging isolation requirements (particularly those defined by standards and regulations). This trend may result in larger packages, which, however, conflicts with the desired more efficient material utilization and the need to reduce manufacturing effort.

[0068] However, the possibility of improving the creepage resistance of the molding compound reaches the technological limit. In addition, the constant application voltage increases from 600V to 1200V, even to 1600V and 2000V. In particular, the package according to an exemplary embodiment can be compatible with application voltages up to at least 3.3kV, up to at least 10kV, up to at least 15kV or even higher. In particular, a creepage resistance relative to an external voltage (e.g. a lightning strike) can be achieved. The required gap distance can increase with increasing breakdown voltage and increasing frequency. In addition, specific applications such as welding, aerospace, aviation, medical devices, etc. may need to operate at a higher pollution level (e.g. PD3).

[0069] Additionally, conventional discrete lead packages may experience different creepage distances between the top and bottom cavities. This may make the electrical characteristics of the conventional package non-uniform.

[0070] According to one embodiment, the package is provided with a carrier (e.g. a lead frame type die pad) on which the electronic component (e.g. a semiconductor power chip) is assembled. An encapsulating material, e.g. a molding compound with filler particles, completely encapsulates the electronic component and the carrier. One or more leads may extend from the encapsulating material at opposite sides of the encapsulating material. The leads may be electrically connected to the carrier and / or to the electronic component, e.g. by one or more connecting wires and / or clips. At least one of the two opposite main surfaces of the encapsulating material may be provided with a (preferably longitudinal) recess extending between two opposite other sides of the encapsulating material, at which no leads are present. Preferably, the difference between the creepage current path length of one lead extending from the encapsulation material at one of the two opposite sides along one of the main surfaces and the recess until another lead extending from the encapsulation material at the other of the two opposite sides and the other creepage current path length from the lead along the other of the main surfaces until the other lead does not exceed 20% (preferably not more than 10% or not more than 5%) of the creepage current path length. In other words, the creepage current path length minus the other creepage current path length divided by the creepage current path length may not exceed ±20%, for example, not more than ±10%. Therefore, due to the recess, a creepage distance balance between opposite main surfaces of the package can be achieved. This promotes high electrical reliability and high electrical performance with simple measures. Therefore, electrical weak points that are prone to creepage current flow can be avoided throughout the package, which allows the package to be operated at high voltage. Advantageously, this can be achieved without increasing the volume of the package, so the package can be manufactured with a low workload.

[0071] More specifically, an exemplary embodiment can provide a high voltage discrete power package with properly balanced and increased creepage distance. In particular, an exemplary embodiment can increase the creepage distance in a discrete power package by creating a recess implemented as a mold cavity on the bottom side of the discrete power package.

[0072] In a specific embodiment, a discrete power package may be provided with gull-wing leads, the discrete power package having a recess or cavity made by molding on its bottom side. The recess or groove may be partially arranged below the die pad type carrier, which may increase the creepage distance. For example, the formation of the recess or cavity may be completed on the top side and / or the bottom side of the encapsulation material so as to achieve a balanced creepage distance between the top cavity and the bottom cavity. In addition, multiple recesses or cavities may be formed on a single side or main surface of the encapsulation material. Preferably, recesses or cavities may be formed on multiple packages by molding. The recess may be formed over the entire length of the molded structure (which may be formed in an ultra-high density manner). Advantageously, the recess or cavity may be terminated by sawing or laser cutting processes on both sides of the package. The ridge formed by the recess between the ridges may be straight without a draft angle. In addition, the formation of a creepage recess or cavity may increase the creepage distance on one side so that the creepage distance is equal to the creepage distance on the other side. Preferably, the package of an exemplary embodiment may be tie-bar free.

[0073] Example embodiments may allow for the production of smaller packages with superior electrical reliability. Thus, a more compact package may be achieved without compromising package performance. Alternatively, the package may be made more reliable over the same footprint.

[0074] In one embodiment, the discrete power package can be equipped with gull-wing leads and preferably with a molded recess or groove area on the bottom side and at least partially under the die pad type package to increase the resulting creepage distance of the package. Preferably, the balanced creepage distance can be adjusted between the top cavity and the bottom cavity by a corresponding recess design. In one embodiment, for example in the context of ultra-high density technology, the creepage cavity can be injected over the entire length of the molded structure. Therefore, the recess or groove can be formed on multiple packages by molding. In a preferred embodiment, the creepage cavity can be terminated by sawing or laser cutting processes on both package sides. The ridges formed by the recesses formed between the ridges can be terminated by singulation without generating a draft angle. The creepage recess or cavity can be configured to be able to increase the creepage distance to the level of the opposite side. In one embodiment, the creepage recess or cavity can be applied at the top and bottom cavities. It may also be advantageous to form multiple creepage recesses or cavities, for example, on one main surface of the encapsulation material.

[0075] A package according to an exemplary embodiment may be configured for high voltage applications (e.g., for voltage levels in the range from 600V to 2000V, such as 1200V or higher, at least 3.3kV, at least 10kV, or at least 15kV). Such voltage may be provided, for example, by an external impact (e.g., a lightning strike). In such a package configuration, creepage currents flowing along the outer surface of the package may generate very undesirable parasitic conductive paths, which may cause problems. In order to reliably prevent such parasitic current paths extending along the outer surface of the package, a creepage distance increasing recess may be formed at the outer surface of the encapsulation material and may be configured to balance the lengths of the creepage current paths along the top main surface and the bottom main surface so that they differ from each other by no more than ±20%, preferably no more than ±10%, more preferably no more than ±5%, and most preferably the same within unavoidable technical tolerances. By forming a recess on at least one main surface of the package, such design rules can be met without increasing the device size and without compromising electrical reliability. Advantageously, a balanced creepage distance may be adjusted by a recess between the top and bottom of the encapsulation material so that the difference between the creepage distance along the top side of the package and along the bottom side of the package is strictly limited.

[0076] An exemplary embodiment may provide a double-sided package with leads on two opposite sides, the leads being associated with different voltage domains during operation of the package. Preferably a recess or groove below the package may enable a more symmetrical and greater creepage distance between the leads on opposite sides of the package. Preferably, the depth of the recess or groove may be limited to a minimum distance requirement in order to ensure that a sufficiently thick isolation mold layer is maintained between the bottom of the recess and the facing encapsulated carrier. Preferably, the minimum distance of the isolation mold layer may be in the range of 100 μm to 300 μm.

[0077] Exemplary applications of the exemplary embodiments are gate drivers, power devices, intelligent power modules (especially gate drivers with power switches), solid-state relays, and the like.

[0078] Figure 1 A cross-sectional view of a package 100 according to an exemplary embodiment is shown. The package 100 may be a discrete power semiconductor device.

[0079] The package 100 includes a carrier 102. The carrier 102 may be implemented as a lead frame structure, for example, may form a portion of a bent and stamped metal sheet (e.g., made of copper). The carrier 102 may be implemented as a die pad carrying an electronic component 108. The electronic component 108 and / or the carrier 102 may be electrically coupled to metal leads 120, 122. The carrier 102 has a top side front side and an opposite bottom side back side facing away from the electronic component 108, on which the electronic component 108 is assembled.

[0080] As shown, the electronic component 108 is mounted on the front side of the carrier 102. For example, the electronic component 108 may be a power semiconductor chip. For example, at least one monolithic integrated circuit element (such as a diode or a transistor) may be monolithically integrated in the semiconductor substrate of the electronic component 108. Figure 1 , only a single electronic component 108 is mounted on the carrier 102, but in other embodiments it is also possible that a plurality of electronic components 108 are mounted on the front side of the carrier 102. For example, one or more electronic components 108 may be mounted on the carrier 102 by soldering, by sintering or by gluing.

[0081] The bottom side pad (not shown) of the electronic component 108 can be electrically coupled to the lead 120, which can be formed integrally with the die pad. The top side pad (not shown) of the electronic component 108 can be electrically coupled to another lead 122, which is a body separated from the die pad type carrier 102. The electrical coupling between the electronic component 108 and the another lead 122 can be achieved by a conductive connection element 182. In the embodiment shown, the conductive connection element 182 is implemented as a connecting wire. Alternatively, the conductive connection element 182 can be a clip (not shown).

[0082] Still reference Figure 1 , the encapsulation material 110 encapsulates the entire electronic component 108 and the entire die pad carrier 102. In other words, the encapsulation material 110 completely encapsulates the electronic component 108 and the carrier 102. In addition, the encapsulation material 110 encapsulates a portion of the leads 120, 122. However, another portion of the leads 120, 122 is exposed relative to the encapsulation material 110. The exposed metal surfaces of the leads 120, 122 can be used to electrically couple the encapsulated electronic component 108 with the peripheral electronic devices of the package 100. Therefore, the metal leads 120, 122 are electrically coupled to the carrier 102 and / or to the electronic component 108, and extend from the encapsulation material 110 at two opposite sides 124, 126 or sidewalls of the encapsulation material 110. The encapsulation material 110 can be a molding compound that mechanically protects the encapsulated electronic component 108 and electrically insulates the encapsulated electronic component 108.

[0083] Advantageously, perpendicular to Figure 1 A groove-shaped recess 132 extending from the plane of the paper is formed in the lower main surface 176 of the encapsulation material 110 and extends between two opposite other sides 128, 130 or sidewalls of the encapsulation material 110. In the embodiment shown, the recess 132 is formed in the main surface 176 of the encapsulation material 110 facing the carrier 102 and away from the electronic component 108. The other side 128 is located Figure 1 The other side 130 is arranged in the plane of the paper. Figure 1 Below or behind the paper plane and parallel to the other side 128. Figure 1 As shown, the leads 120, 122 are laterally spaced apart from the recess 132 by two ridges 136 of the encapsulation material 110 that laterally bound the recess 132. The portions of the gull-wing leads 120, 122 that extend outside of the encapsulation material 110 are bent toward a major surface 176 of the encapsulation material 110 in which the recess 132 is formed. Figure 1 1, but the recess 132 is implemented as a straight groove extending along the entire distance between the two opposite other sides 128, 130 of the encapsulation material 110. Such a recess 132 can be manufactured in a very simple and well-defined manner by molding, as described below with reference to Figures 5 to 7 as described.

[0084] Compared to the molded lower major surface 176, the upper major surface 178 of the encapsulation material 110 is flat, i.e., has no recesses (although one or more recesses may be formed in the upper major surface 178 in other embodiments). The shape and size of the recess 132 in the lower major surface 176 are designed to at least partially balance the difference between the creepage current path lengths A and B between the lead 120 and the lead 122. In the absence of the recess 132, the creepage current path length B would be significantly greater than the creepage current path length A. Because the recess 132 adds an additional path length contribution to the creepage current path length A, the creepage current path length A becomes more similar to or even the same as the creepage current path length B. More specifically, Figure 1 It is shown that parasitic creepage current may flow along the bottom side of encapsulation material 110 from lead 120 to lead 122 along a creepage current path length A. Figure 1 It is also shown that parasitic creepage current may flow along the top side of encapsulation material 110 from lead 120 to lead 122 along another creepage current path length B.

[0085] Due to the recess 132, the creepage current path lengths A, B are adjusted to at least approximately match. More specifically, the shape and size of the recess 132 can be designed so that the difference between the shortest creepage current path length A from the lead 120 extending from the encapsulation material 110 at one of the two opposite sides 124 along the main surface 176 and the recess 132 to the other lead 122 extending from the encapsulation material 110 at the other of the two opposite sides 126 and the shortest other creepage current path length B from the lead 120 along the other main surface 178 to the other lead 122 does not exceed 20% of the creepage current path length A, preferably does not exceed 10%, and more preferably does not exceed 5%. Most preferably, the shape and size of at least one recess 132 are designed so that the shortest bottom-side creepage current path length A between the leads 120, 122 extending from the encapsulation material 110 at the two opposite sides 124, 126 is equal to the shortest top-side other creepage current path length B. When at least one of the mentioned design rules regarding creepage current path length adjustment is observed, electrical weak points in terms of creepage current can be avoided around the entire outer surface of the encapsulation material 110, thereby achieving high electrical reliability and high electrical performance of the package 100. At the same time, providing one recess 132 extends the creepage current path length A and makes the corresponding creepage current path more complicated, thereby further suppressing the risk of creepage current along the bottom side of the package 100. It is very advantageous that these benefits can be achieved by simple measures without increasing the size of the package 100. Instead, a highly compact package 100 with excellent electrical performance can be obtained.

[0086] As shown, the sidewalls at two opposite sides 124, 126 of the encapsulation material 110 are curved. This can be seen by referring to Figures 5 to 7 The molding process described in further detail is used to define the opposite sides 124, 126. The surfaces of the sides 124, 126 may have the following characteristics: Fig.11 The appearance shown.

[0087] Compared to the sides 124, 126, the sidewalls at the two opposite further sides 128, 130 of the encapsulation material 110 are vertical. This may be a unique feature of the further sides 128, 130 defined by cutting. When formed by mechanical cutting using a cutting blade (or when using a femtosecond laser with appropriately adjusted operating parameters), the surface of the further sides 128, 130 may have a shape such as Fig.12 When formed by laser cutting (particularly using a nanosecond laser), the surface of the other sides 128, 130 may have a Fig.13 The appearance shown.

[0088] Advantageously, the package 100 shown is configured as a tie-bar-free package, i.e., no tie-bars are included to reinforce the carrier 102 during the manufacture of the package 100. This can in particular simplify the process of separating the package 100 from the bulk structure, since the separation can be achieved simply by cutting through the material of the encapsulation material. Alternatively, the package 100 can include one or more tie-bars (not shown).

[0089] For example, Figure 1 The package 100 may be implemented as a DSO type package. Figure 1 The package 100 may be suitable for operation at voltages up to 1200 V. For example, the creepage distance between the leads 120 , 122 on the top side may be 5.48 mm, and the creepage distance between the leads 120 , 122 on the bottom side may be 5.48 mm.

[0090] Figure 2 A flow chart 200 is shown of a method of manufacturing a package 100 according to an exemplary embodiment. Reference numerals used in the following description of the manufacturing method refer to Figure 1 Embodiment of the invention.

[0091] Referring to block 202 , the method includes mounting the electronic component 108 on the carrier 102 .

[0092] Referring to block 204 , the method includes completely encapsulating the electronic component 108 and the carrier 102 with the encapsulation material 110 .

[0093] Referring to block 206 , the method includes electrically coupling electrically conductive leads 120 , 122 to the carrier 102 and / or to the electronic component 108 , wherein the leads 120 , 122 extend out of the encapsulation material 110 at two opposing sides 124 , 126 of the encapsulation material 110 .

[0094] Referring to box 208, the method includes forming a recess 132 in at least one of the two opposing main surfaces 176, 178 of the encapsulation material 110, the recess 132 extending between the two opposing other sides 128, 130 of the encapsulation material 110. The difference between a creepage current path length A of one lead 120 extending from the encapsulation material 110 at one side 124 of the two opposing sides along one of the main surfaces 176 and the recess 132 to another lead 122 extending from the encapsulation material 110 at the other side 126 of the two opposing sides and another creepage current path length B from the lead 120 along the other of the main surfaces 178 to the other lead 122 does not exceed 20% of the creepage current path length A.

[0095] Figure 3A side view of package 100 is shown according to an exemplary embodiment. Figure 4 Shown according to Figure 3 A three-dimensional view and detail view 184 of package 100 . Figure 3 and Figure 4 The embodiments correspond largely to Figure 1 Embodiment of the invention.

[0096] like Figure 3 As shown, the ratio between the width W and the depth D of the recess 132 may preferably be at least 5. Therefore, the recess 132 may be wide and shallow, and thus may not significantly affect the outer contour of the package body 100. However, the recess 132 may extend the corresponding creepage current path, may make the creepage current path more complicated, and may balance the creepage current path along the upper side (see reference numeral B) and along the lower side (see reference numeral A) between the leads 120, 122. This may strongly suppress the risk of undesired creepage current inadvertently shorting the leads 120, 122.

[0097] Figure 4 The recess 132 is shown as a straight groove extending along the entire path between the two opposite other sides 128, 130 and is defined laterally between opposite straight and raised ridges 136. This extends the creepage current path length and makes the creepage current path more complex, as shown in FIG. Figure 4 The details are shown in Figure 184.

[0098] Figure 4 Also shown are two leads 120 extending from the encapsulation material 110 at side 124 , while only one lead 122 extends from the encapsulation material 110 at the opposite side 126 .

[0099] according to Figure 3 and Figure 4 The package 100 can be manufactured in an efficient manner by a batch manufacturing process, which will be referred to below. Figures 5 to 7 Describe:

[0100] Figure 5 A three-dimensional view of a structure for manufacturing a package 100 according to an exemplary embodiment is shown before dicing. Figure 6 Another three-dimensional view of a structure for manufacturing a package 100 according to an exemplary embodiment is shown after dicing. Figure 7 A top view of a structure obtained during the manufacture of the package 100 according to an exemplary embodiment is shown.

[0101] First reference Figure 7The manufacturing method includes forming a plurality of packages 100 together in a batch manufacturing process, and includes the following processes:

[0102] As shown at 186, a common carrier structure 150 is provided, which includes a plurality of die pad type carriers 102, each die pad type carrier 102 being configured for assembling a corresponding one of the electronic components 108. The common carrier structure 150 may be a structured metal plate, for example made of copper, and may be implemented as a lead frame. The plurality of leads 120, 122 may form part of a common lead structure 154, which may be integrally formed with the common carrier structure 150.

[0103] As shown by reference numeral 188, a plurality of electronic components 108 (e.g., discrete semiconductor power chips) may be mounted or assembled on a common carrier 150. Each electronic component 108 may be mounted on a designated one of the carriers 102 of the common carrier structure 150. For example, the electronic component 108 may be connected to the carrier 102 by soldering, sintering, or gluing. In addition, the electronic component 108 may be electrically connected to one or more designated leads 120, 122 by conductive connecting elements 182, such as connecting wires and / or clips.

[0104] As indicated by reference numeral 190, the electronic component 108, the carrier 102 and the conductive connection element 182 may be completely encapsulated by the plurality of encapsulating materials 110 of the common strip-shaped encapsulating material structure 152. At the same time, the leads 120, 122 are only partially encapsulated by the common strip-shaped encapsulating material structure 152. Thus, the conductive leads 120, 122 of the common lead structure 154, which are electrically coupled to the carrier 102 and the electronic component 108, respectively, are arranged such that the lead structure 154 extends out of the encapsulating material structure 152 at two opposite sides 156, 158 of the encapsulating material structure 152, see again reference numeral 190. As shown, the encapsulation process includes supplying material 142 of a flowable encapsulating material simultaneously into different flow paths for forming the encapsulating material 110 along a direction 140 corresponding to the extension dimension of the recess 132.

[0105] As shown in the figure numeral 192, the plurality of recesses 132 of the common recess structure 160 are formed in at least one of the two opposite main surfaces 176, 178 of the encapsulation material structure 152, for example, in the main surface 176, so that the common recess structure 160 extends between the two opposite other sides 162, 164 of the encapsulation material structure 152. The formation of the common recess structure 160 can be carried out simultaneously with the encapsulation process. In the embodiment shown, the encapsulation process is a molding process. In the encapsulation process, a plurality of strip-shaped encapsulation material bodies are formed into parallel common strip-shaped encapsulation material structures 152, and the common strip-shaped encapsulation material structures 152 extend parallel to each other as strips. Figure 5 The result of forming the common recess structure 160 simultaneously with the encapsulation process is also shown in FIG. The formation of the common recess structure 160 can be accomplished by a correspondingly shaped molding tool.

[0106] After encapsulation, the exposed metal surfaces of the leads 120 , 122 may be subjected to optional electroplating.

[0107] As shown by reference numeral 194, the method may be performed by breaking the individual packages 100 by punching the leads 120, 122 along the extending direction of the strip-shaped common encapsulation material structure 152, thereby separating the individual packages 100. Therefore, the individual packages 100 may be separated by cutting the leads 120, 122 of the common lead structure 154 outside the common encapsulation material structure 152 along the first direction. In short, the leads 120, 122 may be cut, for example, by punching.

[0108] As shown at reference numeral 196, the method may optionally include a testing and marking process.

[0109] As shown in the figure mark 198, the method can then continue to separate the package 100 by cutting the package 100 along a second direction perpendicular to the first direction. For example, the second disconnection process can be achieved by mechanical cutting (using a cutting blade for separation) and / or laser cutting (using a laser beam for separation). Through the second separation process, the common encapsulation material structure 152 can be separated along a separation direction parallel to the extension direction of the leads 120, 122. Advantageously, the second separation process can only cut through the material of the encapsulation material without cutting through the metal material, which can significantly accelerate the separation process. The result of the cutting separation process is also shown in FIG. Figure 6 shown.

[0110] The method may then continue with packaging the separated packages 100 , as indicated by reference numeral 199 .

[0111] Advantageously, reference Figure 7 The described manufacturing method may allow obtaining a very high number of packages 100 per lead frame area. Figure 7 Involves ultra-high density manufacturing processes.

[0112] Likewise, a design rule for manufacturing the common recess structure 160 may be that the corresponding recess 132 ensures that for each package 100, the difference between a creepage current path length A from one lead 120 extending from the encapsulation material 110 at one of the two opposite sides 124 along one of the main surfaces 176 and the recess 132 to another lead 122 extending from the encapsulation material 110 at the other of the two opposite sides 126 and another creepage current path length B from the lead 120 along the other of the main surfaces 178 to the other lead 122 does not exceed 20%, preferably not exceed 10%, and more preferably not exceed 5% of the creepage current path length A. Most preferably, a configuration may be one in which the recess 132 ensures that the creepage current path lengths A and B are the same.

[0113] Descriptively speaking, Figure 7 Embodiments allow for the formation of grooves or recessed areas for injection flow regulation. The strip-shaped common strip-shaped encapsulating material structure 152, which can be implemented as a molded strip, can be provided with a common recessed structure 160 as a cavity recess on the back side. The common recessed structure 160 can extend in the same direction as the molded strip. Advantageously, incorporating a string of molded grooves in multiple packages allows for the manufacture of an encapsulating material strip layout. The length of the package molded groove can be determined by a single-sided singulation process, in particular cutting or laser cutting. Advantageously, due to the straight ridge design without a draft angle, an increased creepage distance can be achieved. Preferably, the package 100 can be formed according to Figure 7 Manufactured in a tie-bar-free manner. Alternatively, one or more tie-bars may be provided if desired or required. Further advantageously, the described manufacturing architecture may be utilized to achieve balanced creepage distances for asymmetric mold cavities. Furthermore, the described manufacturing concept may provide advantages in terms of warping and torsion of the lead frame. In addition to this, the use and waste of molding compound may be reduced. The recess or groove direction may be the same as the molding flow direction, so that a filamentary structure may be formed. Furthermore, a simplified molding tool manufacturing process may be possible and ejector pins may be placed in the recess area.

[0114] Figure 8 A cross-sectional view of a package 100 according to another exemplary embodiment is shown.

[0115] according to Figure 8 Examples and Figure 1 The embodiments of Figure 8 , the length to height ratio of the encapsulation material 110 is Figure 8 Significantly larger.

[0116] also, Figure 8A vertical distance H is shown between the outer surface of the encapsulation material 110 defined by the recess 132 and the facing surface of the carrier 102. The vertical distance H may be less than 400 μm, and may preferably be in the range from 100 μm to 300 μm.

[0117] For example, Figure 8 The package 100 may be implemented as a DSO type package. Figure 8 The package 100 may be suitable for operation at voltages up to 1700 V. For example, the creepage distance on the top side may be 9.08 mm, and the creepage distance on the bottom side may be 9.08 mm.

[0118] Fig. 9 A cross-sectional view of a package 100 according to yet another exemplary embodiment is shown.

[0119] according to Fig. 9 Examples and Figure 1 The embodiments of Fig. 9 , another recess 134 is formed in the main surface 176 of the encapsulation material 110 and extends between the two opposite other sides 128, 130 of the encapsulation material 110. The recesses 132, 134 extend side by side and parallel to each other. Advantageously, the provision of multiple grooves or recesses 132, 134 can further extend the length of the creepage path along the bottom main surface 176 and can make the creepage path more complex for the passage of creepage current. Therefore, according to Fig. 9 In the embodiment, the creepage current flow can be strongly suppressed.

[0120] For example, Fig. 9 The package 100 may be implemented as a SOT223 type package. Fig. 9 The package 100 may be suitable for operation at voltages up to 1200 V. For example, the creepage distance on the top side may be 5.3 mm, and the creepage distance on the bottom side may be 5.3 mm.

[0121] Fig.10 A cross-sectional view of a package 100 according to yet another exemplary embodiment is shown.

[0122] according to Fig.10 Examples and Figure 1 The embodiments of Fig.10 , the length to height ratio of the encapsulation material 110 is Fig.10 In addition, according to Fig.10 Examples and Figure 1 The embodiment of the present invention is also different in that, according to Fig.10, another recess 134 is formed in the main surface 176 of the encapsulation material 110 and extends between the two opposite other sides 128, 130 of the encapsulation material 110. The recesses 132, 134 extend side by side and parallel to each other. Advantageously, the provision of a plurality of grooves or recesses 132, 134 can further extend the length of the creepage path and make the creepage path more complex for the passage of creepage current. Therefore, according to Fig.10 In the embodiment, the creepage current flow can be strongly suppressed.

[0123] For example, Fig.10 The package 100 may be implemented as a DSO type package. Fig.10 The package 100 may be suitable for operation at voltages up to 2000 V. For example, the creepage distance on the top side may be 12.58 mm, and the creepage distance on the bottom side may be 13.12 mm.

[0124] Therefore, in Figure 8 and Fig. 9 In the case of creepage current, the lengths A and B of the creepage current paths are completely balanced and the same, while according to Fig.10 , the creepage current path lengths A and B are partially balanced.

[0125] Fig.11 A cross-sectional view of a side wall of a package body 100 according to an exemplary embodiment is shown. Fig.11 The curved package sidewalls shown in FIG. 1 are defined by the molding process and correspond to sides 124 , 126 .

[0126] like Fig.11 As shown, the exposed surface of the encapsulating material 110 at the sidewall of each of the two opposite sides 124, 126 has a protrusion 178 formed by the complete filler particles 172 covered with a molded skin 177. In different embodiments, uniformly sized filler particles 172 or filler particles 172 of different sizes (e.g., two or three different sizes) can be used. For example, the encapsulating material 110 can be a molding compound that includes a molding matrix material 170 (e.g., including epoxy resin) filled with filler particles 172 (e.g., ceramic filler particles, such as silicon oxide and / or glass filler, or filler particles made of aluminum oxide for enhancing the thermal conductivity of the encapsulating material 110). When the shape of the sidewall of the side 124, 126 is defined by the molding tool, the surface of the sidewall shows a portion of the molded matrix material 170 and a portion of the filler particles 172 coated with a thin layer of the molded matrix material 170, so that the molded skin 177 coats the filler particles 172 at the exposed sidewall of the side 124, 126. For example, the molded skin 177 may have a thickness in the range of 1 μm to 10 μm, for example 5 μm.

[0127] Fig.12A cross-sectional view of a side wall of a package body 100 according to an exemplary embodiment is shown. Fig.12 The straight vertical package sidewalls shown in FIG. 1 are defined by a mechanical sawing process and correspond to the additional sides 128 , 130 mentioned above.

[0128] like Fig.12 As shown, the exposed surfaces of the encapsulating material 110 at the sidewalls of the two opposing other sides 128, 130 have cut filler particles 172 flush with the molded matrix material 170 of the encapsulating material 110. More specifically, the first surface area of ​​the sides 128, 130 is formed by the flat surface portion of the filler particles 172, while the second surface portion of the sides 128, 130 is formed by the flat surface portion of the molded matrix material 170. When a sharp mechanical cutting blade (or a femtosecond laser) cuts through the encapsulating material 110, portions of the filler particles 172 are also cut away, so that a flat outer surface can remain, which is partially defined by the molded matrix material 170 and partially defined by the cut filler particles 172.

[0129] Fig.13 A cross-sectional view of a side wall of a package body 100 according to yet another exemplary embodiment is shown. Fig.13 The straight vertical package sidewalls shown in FIG. 1 are defined by a laser cutting process and correspond to the additional sides 128 , 130 mentioned above.

[0130] according to Fig.13 , the exposed surfaces of the encapsulating material 110 at the sidewalls of the two opposing other sides 128, 130 have protrusions 180 formed by exposed filler particles 172. The protrusions 180 can be formed by exposed filler particles 172 and can be produced by laser cutting (e.g., using a nanosecond laser), where the laser beam burns away the molding matrix material 170 while leaving the outer filler particles 172 intact. In addition, recesses 174 can be formed at the exposed surfaces of the sides 128, 130, the recesses 174 being defined by curved surfaces corresponding to the curved surfaces of the particles 172 that fall off from the encapsulating material 110 during the laser separation process, see reference numeral 171. In addition, heat-affected features can be visible at the exposed sidewalls of the encapsulating material 110, such as carbides produced by the laser beam.

[0131] Fig.14 1 shows a top view of a structure obtained during the manufacture of a package 100 according to another exemplary embodiment. In short, Fig.14 The embodiment of FIG. 10 involves interdigitated leads 120 , 122 combined with laser singulation. This embodiment allows batch manufacturing of multiple packages 100 using a strip-shaped encapsulation material structure 152 provided in common for many packages 100 .

[0132] Fig.14 A top view 300 of a batch structure before being separated into individual packages 100, a detail view 302 of the top view 300, and a transparent detail view 304 of the top view 300 are shown. Fig.14 A detail image 312 of a top view of the batch structure after separation into individual packages 100 is shown, as well as a transparent detail image 314 corresponding to the detail image 312. Fig.14 , separation can be accomplished by laser processing.

[0133] Fig.14 Examples and Figure 7 The embodiments of Fig.14 , the leads 120, 122 assigned to adjacent encapsulation material structures 152 are not like Figure 7 In contrast, adjacent leads 120, 122, which are assigned to adjacent encapsulation material structures 152 and are arranged along a direction corresponding to the extension of the encapsulation material structures 152, are displaced relative to each other in an overlapping manner transversely to the direction corresponding to the extension of the encapsulation material structures 152, so as to form an interdigitated lead arrangement structure, as shown in FIG. Fig.14 This makes Fig.14 It is unnecessary to separate the common lead structure 154 into leads 120, 122, which simplifies the manufacturing process.

[0134] In order to implement Fig.14 In the manufacturing process of the present invention, a plurality of electronic components 108 are mounted on a plurality of carriers 102 of a common carrier structure 150. The electronic components 108 and the carriers 102 are encapsulated by a plurality of encapsulating materials 110 of a common parallel strip-shaped encapsulating material structure 152. A plurality of conductive leads 120, 122, which are implemented as interdigital leads here, are electrically coupled to the carriers 102 and the electronic components 108, such that the leads 120, 122 extend out of the encapsulating material structure 152 at two opposite sides 156, 158 of the encapsulating material structure 152. In addition, a plurality of recesses 132 of a common recess structure 160 may be formed in at least one of the two opposite main surfaces 176, 178 of the encapsulating material structure 152, such that the common recess structure 160 extends between two opposite other sides 162, 164 of the encapsulating material structure 152. The encapsulation material structure 152 can then be separated by laser cutting, wherein the individual cutting lines can be shifted along a direction corresponding to the extension of the encapsulation material structure 152, see detail views 312, 314. By this separation, individual packages 100 can be obtained.

[0135] It should be noted that the term "comprising" does not exclude other elements or features, and "one" or "an" does not exclude a plurality. Elements described in association with different embodiments may also be combined. It should also be noted that the reference numerals should not be interpreted as limiting the scope of the claims. In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods and steps described in the specification. Therefore, the appended claims are intended to include these processes, machines, manufactures, compositions of matter, means, methods or steps within their scope.

Claims

1. A package (100), comprising: A carrier (102); An electronic component (108) mounted on the carrier (102); An encapsulation material (110) which completely encapsulates the electronic component (108) and the carrier (102); Conductive leads (120, 122) electrically coupled to the carrier (102) and / or to the electronic component (108) and on two opposite sides (124, 126) extending from the encapsulating material (110); and A recess (132) located on two opposite major surfaces (176, 178) and extending between two opposing other sides (128, 130) of the encapsulating material (110); ·Wherein, a difference between a creepage current path length (A) of one lead (120) extending from the encapsulating material (110) at one of the two opposite sides (124) along one of the main surfaces (176) and the recess (132) to another lead (122) extending from the encapsulating material (110) at the other of the two opposite sides (126) and another creepage current path length (B) from the lead (120) along the other of the main surfaces (178) to the other lead (122) does not exceed 20% of the creepage current path length (A).

2. The package (100) according to claim 1, wherein: The package (100) comprises at least one of the following features: The side walls at the two opposite sides (124, 126) of the encapsulation material (110) are at least partially curved; The exposed surface of the encapsulating material (110) at the side walls of the two opposite sides (124, 126) has protrusions (178) formed of filler particles (172) covered with a molded skin (177).

3. The package (100) according to claim 1 or 2, wherein: The package (100) comprises at least one of the following features: The side walls at the two opposite other sides (128, 130) of the encapsulation material (110) are vertical; The exposed surface of the encapsulating material (110) at the sidewalls of the two opposite other sides (128, 130) has at least one of the following: a protrusion (180) formed by exposed filler particles (172); a recess (174) defined by a curved surface; a cut filler particle (172) flush with the molded matrix material (170) of the encapsulating material (110); and heat-affected features such as carbides.

4. The package (100) according to any one of claims 1 to 3, wherein: The package (100) is configured as a tie-bar-less package.

5. The package (100) according to any one of claims 1 to 4, wherein: The recess (132) is formed in a main surface (176) of the encapsulation material (110) that faces the carrier (102) and faces away from the electronic component (108).

6. The package (100) according to any one of claims 1 to 4, wherein: The recess (132) is formed in a main surface (178) of the encapsulation material (110) facing away from the carrier (102) and facing the electronic component (108).

7. The package (100) according to any one of claims 1 to 6, wherein: The package (100) includes a further recess (134) located in at least one of the two opposing major surfaces (176, 178) of the encapsulation material (110) and extending between the two opposing further sides (128, 130) of the encapsulation material (110).

8. The package (100) according to claim 7, wherein: The further recess (134) is formed in the same main surface (176) as the recess (132) and extends parallel to the recess (132).

9. The package (100) according to claim 7, wherein: The further recess (134) and the recess (132) are formed in two opposite main surfaces (176, 178) of the encapsulation material (110) and extend parallel to each other.

10. The package (100) according to any one of claims 1 to 9, wherein: The leads (120, 122) are spaced apart from the recess (132) by ridges (136) of the encapsulation material (110), the ridges (136) laterally bounding the recess (132).

11. The package (100) according to any one of claims 1 to 10, wherein: At least the portions of the leads (120, 122) extending outside the encapsulation material (110) are bent at least partially toward the major surface (176) of the encapsulation material (110) in which the recess (132) is formed.

12. The package (100) according to any one of claims 1 to 11, wherein: The recess (132) extends along the entire distance between the two opposing further sides (128, 130) of the encapsulation material (110).

13. The package (100) according to any one of claims 1 to 12, wherein: The recess (132) is a groove, such as a straight groove.

14. The package (100) according to any one of claims 1 to 13, wherein: The package (100) comprises at least one of the following features: The ratio between the width (W) and the depth (D) of the recess (132) is at least 2, for example at least 5; The difference does not exceed 10% of the creepage current path length (A); The difference is zero; A vertical distance (H) between an outer surface of the encapsulation material (110) defined by the recess (132) and a facing surface of the carrier (102) is less than 400 μm, in particular in the range of 100 μm to 300 μm; The leads (120, 122) are gull-wing shaped; The package (100) is configured as a power package; The electronic component (108) is a power chip; The carrier (102) includes a lead frame type die pad.

15. A method for manufacturing a package (100), the method comprising: Mounting the electronic component (108) on the carrier (102); Completely encapsulating the electronic component (108) and the carrier (102) by an encapsulation material (110); electrically coupling conductive leads (120, 122) to the carrier (102) and / or to the electronic component (108), the leads (120, 122) extending from the encapsulation material (110) at two opposite sides (124, 126) of the encapsulation material (110); and forming a recess (132) in at least one of the two opposing major surfaces (176, 178) of the encapsulating material (110), the recess (132) extending between two opposing further sides (128, 130) of the encapsulating material (110); ·Wherein, a difference between a creepage current path length (A) of one lead (120) extending from the encapsulating material (110) at one of the two opposite sides (124) along one of the main surfaces (176) and the recess (132) to another lead (122) extending from the encapsulating material (110) at the other of the two opposite sides (126) and another creepage current path length (B) from the lead (120) along the other of the main surfaces (178) to the other lead (122) does not exceed 20% of the creepage current path length (A).

16. The method according to claim 15, wherein: The method includes supplying a material (142) of a flowable encapsulating material for forming the encapsulating material (110) along a direction (140) corresponding to an extension of the recess (132).

17. The method according to claim 15 or 16, wherein: The method comprises forming the package (100) together with another package (100) in a batch manufacturing process, the batch manufacturing process comprising: · mounting a plurality of electronic components (108) on a plurality of carriers (102) of a common carrier structure (150); Completely encapsulating the electronic component (108) and the carrier (102) by a plurality of encapsulation materials (110) of a common strip-shaped encapsulation material structure (152); electrically coupling a plurality of electrically conductive leads (120, 122) of a common lead structure (154) to the carrier (102) and / or to the electronic component (108) such that the lead structure (154) extends from the encapsulation material structure (152) at two opposite sides (156, 158) of the encapsulation material structure (152); and A plurality of recesses (132) forming a common recess structure (160) in at least one of two opposing major surfaces (176, 178) of the encapsulating material structure (152) such that the common recess structure (160) extends between two opposing further sides (162, 164) of the encapsulating material structure (152).

18. The method according to claim 17, wherein: The method includes separating the packages (100) by breaking, for example by punching, the leads (120, 122) of the common lead structure (154) that are external to the common encapsulating material structure (152).

19. The method according to claim 15 or 16, wherein: The method comprises forming the package (100) together with another package (100) in a batch manufacturing process, the batch manufacturing process comprising: · mounting a plurality of electronic components (108) on a plurality of carriers (102) of a common carrier structure (150); Completely encapsulating the electronic component (108) and the carrier (102) by a plurality of encapsulation materials (110) of a common strip-shaped encapsulation material structure (152); electrically coupling a plurality of electrically conductive leads (120, 122), for example interdigitated leads, to the carrier (102) and / or to the electronic component (108), such that the leads (120, 122) extend from the encapsulation material structure (152) at two opposite sides (156, 158) of the encapsulation material structure (152); and A plurality of recesses (132) forming a common recess structure (160) in at least one of two opposing major surfaces (176, 178) of the encapsulating material structure (152) such that the common recess structure (160) extends between two opposing further sides (162, 164) of the encapsulating material structure (152).

20. The method according to any one of claims 17 to 19, wherein: The method comprises separating the packages (100) by breaking, for example by cutting, in particular mechanically and / or laser cutting, the common encapsulation material structure (152) along a separation direction corresponding to the extension direction of the leads (120, 122).

Images