Package with concave wettability and / or metallization layers

Abstract

A component (102) for a package (100) wherein the component (102) comprises a functional body (108) and a wettability layer (110) arranged on a major surface of the functional body (108) and configured to promote wetting of a connection medium (112) to be applied on the wettability layer (110), the wettability layer (110) has a connection medium (112) for connecting the component (102) to a further component (104) of the package (100), the wettability layer (110) having a lateral periphery, at least a portion of which has a concave edge (114).

Description

Technical Field

[0001] Various embodiments generally relate to a component for a package, a package, and a method of manufacturing a package. Background Art

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

[0003] In conventional packages, a rectangular wettability layer on a lead frame structure for carrying a semiconductor chip may define an area in which a solder material for connecting the lead frame structure to the semiconductor chip may be formed. However, undesirable phenomena such as solder seeping out at the edge of the chip and / or solder not completely covering the chip corners may occur. Therefore, the reliability of conventional packages may be an issue due to inaccurate soldering or adhesion during chip assembly. Summary of the invention

[0004] A package having high reliability may be desired.

[0005] According to an exemplary embodiment, a component for a package is provided, wherein the component comprises a functional body and a wettability layer, wherein the wettability layer is arranged on a main surface of the functional body and is configured to promote wetting of a connecting medium to be applied on the wettability layer, wherein the connecting medium is used to connect the component to another component of the package, wherein the wettability layer has a lateral periphery, at least a portion of which has a concave edge.

[0006] According to another exemplary embodiment, a package is provided, comprising a component having the above features, another component and a connecting medium, wherein the another component is connected to the component via the connecting medium on the wettability layer.

[0007] According to an exemplary embodiment, a method for manufacturing a package is provided, wherein the method comprises: arranging a wettability layer on a main surface of a functional body of a component for promoting wetting of a connecting medium to be applied on the wettability layer; forming the wettability layer having a lateral periphery, at least a portion of the lateral periphery having a concave edge; applying the connecting medium on the wettability layer; and connecting the component to another component via the connecting medium.

[0008] According to another exemplary embodiment, a package is provided, comprising a carrier, a semiconductor chip having a conductive connection layer, and a connection medium connecting the conductive connection layer to the carrier, wherein the conductive connection layer has a lateral periphery, at least a portion of which has a concave edge.

[0009] According to an exemplary embodiment, a package manufacturing architecture can be provided, wherein a component (e.g., a lead frame structure) and another component (e.g., a semiconductor chip) are connected by a connecting medium (e.g., solder or assembly adhesive) attached to a wettability layer of the component. Descriptively, the wettability layer should define an area in which a connecting medium can be provided and retained, while substantially no connecting medium should be retained outside or around the wettability layer. Advantageously, the wettability layer can be formed with a lateral periphery, at least a portion of which has a concave edge. It has been surprisingly found that by promoting the wetting of the connecting medium along at least a portion of the periphery of the wettability layer, at least partially concave edges or edge portions can achieve beneficial and well-defined target properties of the obtained component-component connection structure. More specifically, by forming the edge of the wettability layer in a concave manner, unintentional seepage of the connecting medium at the edge of the component can be reliably prevented. In addition, the concave edge can improve the coverage of the corners of the component by the connecting medium. These benefits have been confirmed by simulations and experiments. Therefore, the correspondingly manufactured package can exhibit excellent mechanical and electrical reliability. For example, the concave shape may be a stepped profile or a smooth (or continuously curved) profile. Additionally or alternatively, the metallization layer of the semiconductor chip may have a concave shape.

[0010] Description of Further Exemplary Embodiments

[0011] In the following, further exemplary embodiments of a component, a package and a method will be explained.

[0012] 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 optionally be at least partially 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.

[0013] In the context of the present application, the term "component" may particularly denote any member, component or element of a package (e.g. a chip package). For example, the component (and / or the further component) may be a chip carrier such as a lead frame structure, a conductive connection element such as a clip and / or an electronic component such as a semiconductor die.

[0014] In an embodiment, the component is configured as one of: a leadframe structure (or another carrier for electronic components such as semiconductor chips); a clip; and an electronic component, such as a semiconductor chip.

[0015] 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 (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 material 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 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. In addition, at least a portion of the carrier may be encapsulated with the electronic components by an encapsulation material.

[0016] In the context of the present application, the term "lead frame" may particularly denote a sheet metal structure which may be bent, stamped and / or patterned so as to form a lead frame body as a mounting section for mounting a chip and connecting leads for electrically connecting the package to an electronic environment. In one embodiment, the lead frame may be a metal plate (in particular made of copper) which may be patterned, for example, by stamping or etching. Forming the chip carrier as a lead frame is cost-effective and a mechanically and electrically highly advantageous configuration in which a low-ohmic connection of the chip may be combined with the solid supporting capabilities of the lead frame. In addition, the lead frame may contribute to the thermal conductivity of the package and may remove heat generated during operation of the chip due to the high thermal conductivity of the metal (in particular copper) material of the lead frame.

[0017] 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 loudspeakers) and micro-electromechanical systems (MEMS). However, in other embodiments, the electronic components 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 with silicon technology, gallium nitride technology, silicon carbide technology, etc.

[0018] In the context of the present application, the term “clip” may particularly denote a three-dimensionally bent connecting element comprising an electrically conductive material such as copper and being an integral body having sections to be connected to chip terminals and / or chip carrier and / or leads.

[0019] In the context of the present application, the term "functional body" may particularly refer to the physical structure of the component that provides at least a portion of the target function of the component. For example, when the component is a lead frame structure, the functional body may be a die pad of the lead frame structure for accommodating an electronic component such as a semiconductor die or chip. When the component is a clip, the functional body may be a patterned and / or curved conductive plate having a coupling interface for coupling an electronic component such as a semiconductor die. In an embodiment in which the component is an electronic component such as a semiconductor chip, the functional body may be a semiconductor substrate having a monolithic integrated circuit element in an active region and having a metal connection structure (e.g., a pad or terminal) thereon. The functional body of a component may be configured to be connected to another component.

[0020] In the context of the present application, the term "wetting layer" may particularly denote, for example, a flat or planar film, sheet or plate having surface properties that promote wetting of a connecting medium (e.g., solder or adhesive) thereon (e.g., flowable during processing). In particular, wetting may denote the ability of the connecting medium to maintain contact with the solid surface of the wettability layer, in particular the ability resulting from intermolecular interactions when the two are combined together. The degree of wetting may be expressed as wettability and may be determined by the force balance between adhesion and cohesion.

[0021] In the context of the present application, the term "connecting medium" may particularly denote a material that can be configured to preferably mechanically and electrically connect a component to another component. Such a connecting medium may be flowable during processing and may be (particularly permanently) solid by hardening, curing or the like. Examples of connecting media are solders, glues or assembly adhesives, or even sinterable or semi-sinterable materials.

[0022] In the context of the present application, the term "lateral periphery of the wettability layer" may particularly denote the closed periphery of the wettability layer between two opposite main surfaces of the wettability layer. Thus, the lateral periphery of the wettability layer may relate to the thin side walls of the wettability layer rather than to its larger top and bottom main surfaces. Preferably, the entire lateral periphery of the wettability layer may lie in a common plane.

[0023] In the context of the present application, the term "at least partially concave edge of the wettability layer" may particularly denote at least a portion of the circumference of the edge of the wettability layer (e.g. a side edge or a segment of a side edge or the entire circumferential side edge) which has a profile that curves inwards at least in one segment. In particular, concave may mean curving inwards, e.g. curving inwards towards the center of the wettability layer. Thus, the at least partially concave edge of the wettability layer may produce at least one notch or recess in the edge region between two adjacent corners. Such an inwardly curved profile or profile portion of the edge may be defined by a continuously curved or smooth profile segment (e.g. see Figure 6 ), or by contour segments defined by a stepped sequence of contour segment parts (see, for example Figure 1 or Figure 7 In other embodiments, combinations between continuously curved, stepped and / or straight profile sections along the outer periphery of the wettability layer are also possible.

[0024] In the context of the present application, the term "main surface" of a body may particularly denote one of the largest body surfaces. For example, a body (e.g. a clip or a carrier or a chip or a wettability layer or a part thereof) may be plate-shaped or substantially plate-shaped and may here have two opposite main surfaces separated in the thickness direction by body material and connected to each other by a circumferential edge.

[0025] In one embodiment, the wettability layer is a plated layer. The plated layer may be a layer formed at least in part by plating, for example by depositing a metal on a surface (e.g. by chemical plating or sputtering). Concave plating may be performed directly on components such as lead frames, clips or chips. A sputtering mask may be used in the process to define the partially or fully concave perimeter of the wettability layer, as such a mask may be provided with any desired shape.

[0026] In one embodiment, when the component is configured as a lead frame structure or a clip, the coating includes or consists of silver. Silver can have excellent wetting properties so that the solder can be evenly distributed on the silver surface of the coating, rather than being separated or split into multiple separate solder islands on the wettability layer. Advantageously, the silver coating can provide better wetting than other materials (such as copper). Therefore, the silver material can actively control the seepage characteristics. In particular, it has been found that the silver coating can help to confine the solder under the chip, that is, to inhibit the seepage of the solder. Silver materials and other types of materials can be particularly preferably used on lead frames (especially for bare die pads) or clips.

[0027] In one embodiment, when the component is configured as an electronic component, such as a semiconductor chip, the plating layer includes or consists of one of the following group, the group including palladium, gold, titanium, nickel and NiNiP. The material shows very good wetting properties on the semiconductor chip. Therefore, the appropriate plating material on the chip can be palladium, gold, titanium or others.

[0028] Although the plating materials mentioned in the previous paragraphs may be preferred choices, the plating material can be any material that has an affinity for the connection medium to be achieved (particularly solder). For example, silicon does not have such an affinity (i.e., solder cannot properly wet silicon). Therefore, plating can be performed in order to make silicon wettable. On the die pad, the main purpose of plating can be to guide the diffusion and / or distribution of the solder.

[0029] In one embodiment, the wettability layer has a concave edge along its entire lateral periphery. This ensures excellent properties in terms of preventing seepage and proper corner coverage with the connecting medium over the entire extension of the wettability layer.

[0030] However, it is also possible that only a portion of the circumferential edge of the wettability layer is concave, while another portion of the circumferential wettability layer is non-concave (e.g. comprising one or more straight and / or convex edge segments). For example, a concave edge may be formed where the gap distance of a further component (e.g. a semiconductor chip) on a component (e.g. a lead frame structure) is small. If there are areas of large gap resistance, the concavity of the edge may be locally omitted in such areas. For example, when a small gap distance exists everywhere around the further component, the wettability layer may have a concave edge along each of the four sides of its substantially rectangular lateral periphery.

[0031] In one embodiment, the concave edge is a stepped concave edge having a plurality of steps. For example, when (eg, inner or outer) stepped corners are connected to each other by an imaginary curve, the line may be concave (see Figure 1 166 in the figure). Advantageously, the stepped profile can be useful for controlling the so-called Marangoni effect when applied to the behavior of the connecting medium on the wettability layer. The Marangoni effect is related to the concentration dependence of the surface tension. The Marangoni effect can represent the mass transfer that occurs along the interface between two phases due to the gradient of the surface tension. In short, since the surface tension depends on the concentration, the stepped concave edge can particularly reliably prevent the connecting medium (e.g., flowable solder) from excessively seeping out beyond the limits of the stepped concave edge. The mentioned steps of the concave edge may also have an impact on the local evaporation rate. More specifically, the evaporation rate may be locally higher where there are steps and locally lower between adjacent steps. This phenomenon can contribute to an appropriate meniscus structure geometry of the connecting medium on the wettability layer.

[0032] In one embodiment, the steps are formed by step angles in the range of 45° to 135°, for example in the range of 60° to 120°, more particularly in the range of 80° to 100° (see Figure 1 The step angle may be defined by the "β" in the step. Such a step angle may be present at the outer step and / or the inner step. Preferably, the step angle of the step may be 90° or may be approximately 90°. In view of the Marangoni effect, the mentioned angle range is particularly suitable for adjusting the desired properties of the wettability layer.

[0033] In one embodiment, at least a portion of the concave edge is formed at one side of the lateral periphery between two corners, wherein the concave portion of the concave edge leads to an innermost central edge portion between the two corners. Descriptively speaking, this geometry of the wettability layer can pull the connecting medium inwardly in the innermost central portion of the concave edge, while the connecting medium can be pulled outwardly at or around the corners between adjacent concave edges. Thus, the described geometry can simultaneously promote improved component (e.g., chip) corner coverage and strong suppression of oozing out at the edge of the component (e.g., chip).

[0034] In one embodiment, the corner at the interface between two adjacent edges of the wettability layer may have an angle in the range of 45° to 135°, for example in the range of 60° to 120°, preferably 90° or at least about 90° (which may be expressed as a corner angle, see Figure 3 In the mentioned angle range, advantageous corner coverage can be achieved by the connecting medium.

[0035] In one embodiment, the concave edge has at least two steps along the one side, for example at least four or at least six steps. As already mentioned, a stepped concave edge may be advantageous, in particular in view of the Marangoni effect. The number of steps along one edge between two adjacent corners may be even, for obtaining uniform properties in terms of oozing suppression and corner coverage along the entire perimeter. The number of steps per edge is in the range from 2 to 6, preferably an even number of steps per edge within said range, which may be a highly appropriate compromise between simplicity and efficiency, in particular in view of the Marangoni effect.

[0036] In one embodiment, the connection medium comprises solder. In the context of the present application, the term "solder" may be a solderable material that can be subjected to soldering to establish a conductive solder connection between a component and another component. For example, such a solder structure may be a solder film or solder layer, or may be a solder bump. For example, a solder paste having a lead-based or bismuth-based solder material may be used. A solder structure comprising tin may also be used.

[0037] In one embodiment, the connection medium includes an assembly adhesive. In one embodiment, the assembly adhesive can be an adhesive, such as a conductive adhesive. It is also possible that this assembly adhesive can be a die attach paste. The assembly adhesive can also be any resin-based assembly adhesive, including semi-sintered materials. With regard to mixed and semi-sintered materials, the corresponding paste can be a partially adhered and partially sintered paste, such as a silver-filled adhesive. Therefore, the assembly adhesive can be resin-based, and the pure sintered product can be solvent-based. They can be manipulated with the same or similar process as other die attach adhesives. Therefore, all resin-based die attach or assembly materials can be used as connection media. For example, the assembly adhesive can be epoxy-based, or based on acrylic acid, silicone, bismaleimide (BMI) and / or mixed materials.

[0038] In one embodiment, the component is a chip carrier, such as a lead frame structure, and the additional component is an electronic component, such as a semiconductor chip. When the semiconductor chip is assembled on the chip carrier by soldering or using an assembly adhesive, the wettability layer with concave edges on the chip carrier can allow the semiconductor chip to be assembled without excessive solder oozing out and / or with rectangular corners that exhibit adequate solder coverage.

[0039] In another embodiment, the component is a clip (e.g. a bent and patterned metal structure) and the further component is an electronic component, such as a semiconductor chip (e.g. a power semiconductor chip). When the semiconductor chip is assembled on the clip by soldering or using an assembly adhesive, or vice versa, a wettability layer with concave edges on the clip and / or the chip can allow to build a package with advantageous properties in terms of solder oozing out and covering corners with solder material.

[0040] In one embodiment, the package comprises a third component (e.g. a carrier (such as a lead frame structure), a clip or an electronic component) and an additional connection medium (e.g. an additional solder or an additional assembly adhesive), wherein the third component is connected to the additional component via the additional connection medium located on the additional component and / or on an additional wettability layer of the third component, the additional wettability layer having a lateral periphery, at least a portion of which has a concave edge (and more generally, the additional wettability layer can be implemented as the above-mentioned wettability layer). In short, the package can be formed as a component stack comprising at least three stacked components, wherein a concave wettability layer on one or two of the connected components can be used to establish a connection between each adjacent pair of components.

[0041] Still referring to the previously described embodiments, the package comprises a fourth component (e.g. a carrier (such as a lead frame structure), a clip or an electronic component) and a third connecting medium (e.g. a further solder or a further assembly adhesive), wherein the fourth component is connected to the third component via the third connecting medium located on the third component and / or on a third wettability layer of the fourth component, the third wettability layer having a lateral periphery, at least a portion of which has a concave edge (and more generally, the third wettability layer can be implemented as the above-mentioned wettability layer). For example, the component can be a chip carrier, the further component can be a semiconductor chip, and the third component can be a clip. For example, the fourth component can be a further semiconductor chip. Thus, complex component stacks can be created with multiple wettability layers with concave edges. Fig. 9 An example is shown in , which shows a stack of a lead frame type carrier, a semiconductor chip on the lead frame type carrier, a clip on the semiconductor chip, and another semiconductor chip on top of the clip. Many other combinations of three, four, five or more stacked components are possible.

[0042] In one embodiment, the package is configured as a power package. The power package may be a package including at least one power chip as an 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 Power Module). Another exemplary embodiment of the package is a dual inline package (DIP: Dual Inline Package).

[0043] Accordingly, the electronic component can be configured as a power semiconductor chip. Therefore, the electronic component (e.g., a 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 can include one or more field effect transistors, diodes, inverter circuits, half bridges, full bridges, drivers, logic circuits, other devices, etc.

[0044] In one embodiment, the package includes an encapsulation material that encapsulates at least a portion of the components, such as at least a portion of the carrier and at least a portion of the electronic components. In the context of the present application, the term "encapsulation material" can particularly represent a substantially electrically insulating material that surrounds at least a portion of the electronic components and at least a portion of the carrier, to provide mechanical protection, electrical insulation, and optionally a contribution to heat dissipation during operation. In particular, the encapsulation material can be a molding compound. The molding compound can include a matrix of a flowable and hardenable material and filler particles embedded therein. For example, filler particles can be used to adjust the characteristics of the molded component, particularly to enhance thermal conductivity. As an alternative to a molding compound (e.g., based on epoxy resin), the encapsulation material can also be a potting compound (e.g., based on silicone gel).

[0045] In one embodiment, the package comprises a conductive coupling element electrically coupling the component to the further component, for example a conductive coupling element electrically coupling the electronic component to a carrier and / or to at least one lead structure. Such a conductive coupling element may be a clip, a connecting wire or a connecting ribbon.

[0046] In one embodiment, at least one side of the lateral periphery of the wettability layer has a concave edge, and the concave edge has at least two concave notches in the corresponding side. It has been found that forming two, three or more concave notches in one (e.g. straight) side of a (e.g. roughly rectangular) wettability layer can form a favorable solder pattern on such a wettability layer. In addition, forming a plurality of notches with concave features in such a wettability layer can allow solder to be avoided in a specific area corresponding to a concave portion of a material where the wettability layer is not present. For example, in the case where a specific surface area should be prevented from being covered by solder, a plurality of concave portions can allow this purpose to be achieved. For example, such recessed areas can be those recessed areas where active devices (e.g., other components connected to the wettability layer and the functional body, such as semiconductor chips) are located, and these areas should not be electrically connected to the solder material.

[0047] In one embodiment, the functional body has a lateral periphery, at least a portion of which has a concave edge that follows the concave contour of the concave edge of the wettability layer. Advantageously, the functional body itself, and not just the wettability layer on the functional body, may also have concave properties along at least a portion of the periphery of the functional body. At least in the concave section of the contour of the wettability layer, the functional body may also have a corresponding concave section that follows the shape of the concave section of the wettability layer.

[0048] Still referring to the previously described embodiments, the functional body (which may have a lateral periphery, at least a portion of which has a concave edge that follows the concave contour of the concave edge of the wettability layer) comprises or consists of a die pad. For example, such a die pad may be a conductive chip carrier (e.g. a lead frame structure) or a portion of the conductive chip carrier on which further components (e.g. a semiconductor chip) may be mounted. This may allow the functional body to be manufactured with a small amount of material without compromising its functionality. Furthermore, this may support the function of the concave edge of the wettability layer to keep active devices or the like, for example further components of the connection, free of conductive material.

[0049] In one embodiment, the entire lateral periphery of the wettability layer is located inside the entire lateral periphery of the functional body, so that the area of ​​the main surface of the functional body is larger than the area of ​​the wettability layer. In particular, when the functional body approximately (e.g., at least in the corresponding concave area) follows the contour of the wettability layer, the slightly larger main surface area of ​​the functional body compared to the wettability layer area can promote better support for connected further components, such as semiconductor chips.

[0050] In one embodiment, the further component (e.g. a semiconductor chip) has an exposed conductive connection layer for connection to the wettability layer via the connection medium, the exposed conductive connection layer (e.g. a chip metallization, which may be a front metallization and / or a back metallization) having a lateral periphery, at least a portion of which has a concave edge. Thus, with respect to the exposed conductive connection layer of the further component, there may also be an at least partially concave profile of the wettability layer. This may facilitate automatic alignment between the functional body and the further component during assembly.

[0051] In one embodiment, the concave edge of the exposed conductive connection layer follows the contour of the concave edge of the wettability layer. In particular, the exposed conductive connection layer facing the wettability layer and having a connecting medium between the wettability layer and the exposed conductive connection layer can have one or more concave edge sections where the wettability layer has one or more concave edge sections. In addition, when the functional body and the other component are assembled using the connecting medium between the functional body and the other component, this can promote automatic alignment between the functional body and the other component.

[0052] In one embodiment, at least a portion of the concave edge of the exposed conductive connection layer is laterally bounded by an electrically insulating and / or non-weldable bounding structure of the further component. For example, such an electrically insulating and / or non-weldable bounding structure may be arranged along a portion of the exposed conductive connection layer or even along the entire periphery of the exposed conductive connection layer. An example of the electrically insulating and / or non-weldable bounding structure is an epoxy material. Descriptively, such an electrically insulating and / or non-weldable bounding structure may define or delimit a weldable area of ​​the exposed conductive connection layer.

[0053] In one embodiment, in addition to the exposed electrically conductive connection layer, the delimiting structure also covers the functionally active structure of the further component. Such a functionally active structure can be, for example, an active area of ​​a further component of the semiconductor chip type, which should be covered by the electrically insulating and / or non-solderable delimiting structure and can therefore be decoupled from the connecting medium, for example solder.

[0054] In one embodiment, the exposed conductive connection layer is made of a solderable material, which can be a material that can form a mating structure in a solder connection, such as a copper metallization layer.

[0055] In one embodiment, the further component is a semiconductor chip (eg a power semiconductor chip) and its exposed electrically conductive connection layer is a chip metallization layer (eg a front side metallization and / or a back side metallization).

[0056] In one embodiment, the semiconductor chip is subjected to vertical current flow during operation of the package. For example, the semiconductor chip may be a chip having both a front side metallization and a back side metallization for forming terminals or pads for establishing electrical connections, such that during operation of the package, current flows between the front side metallization and the back side metallization. For example, the semiconductor chip may be a transistor chip having a source terminal, a drain terminal and a gate terminal, such as having the source terminal and the drain terminal on opposite main surfaces of the semiconductor chip.

[0057] In one embodiment, the package is configured as one of the group consisting of a lead frame connected power module, a control integrated power system (CIPOS) package, a transistor outline (TO) package, a quad flat no-lead package (QFN) package, a small outline (SO) package, a small outline transistor (SOT) package and a thin small outline package (TSOP) package.

[0058] As a substrate or wafer forming the basis for one or more electronic components, 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.

[0059] 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

[0060] The accompanying drawings, which are included to provide a further understanding of exemplary embodiments and constitute a part of this specification, illustrate exemplary embodiments.

[0061] In the attached picture:

[0062] Figure 1 A three-dimensional view of a package according to an exemplary embodiment is shown.

[0063] Figure 2 A top view of a conventional package according to a simulation is shown.

[0064] Figure 3 A top view of a simulated package according to an exemplary embodiment is shown.

[0065] Figure 4 An image of a conventional package is shown.

[0066] Figure 5 An image showing a package according to an exemplary embodiment is shown.

[0067] Figure 6 A top view of components for a package according to an exemplary embodiment is shown.

[0068] Figure 7 A top view of components for a package according to another exemplary embodiment is shown.

[0069] Figure 8 A top view of a package according to another exemplary embodiment is shown.

[0070] Fig. 9 A cross-sectional view of a package according to yet another exemplary embodiment is shown.

[0071] Fig.10 Different views of components of a package according to an exemplary embodiment are shown.

[0072] Fig.11 Shown by Fig.10A top view of a package body formed by components.

[0073] Fig.12 Shown is the Fig.10 and Fig.11 A detailed 3D view of the components of the package.

[0074] Fig.13 Shows about Fig.11 Simulation results of the solder coverage of the package.

[0075] Fig.14 A top view of a package is shown with different commonly occurring assembly problems.

[0076] Fig.15 A top view of a package according to an exemplary embodiment is shown, wherein assembly issues are overcome by the self-alignment functionality of features of the exemplary embodiment.

[0077] Fig.16 Shows about Fig.15 Simulation results of the solder coverage of the package. DETAILED DESCRIPTION

[0078] The illustrations in the drawings are schematic and not to scale.

[0079] 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.

[0080] In conventional methods, when soldering large chips on lead frames, there is a risk of oozing out or solder overflow, i.e. solder flowing into areas where solder is not required. Especially in the presence of large chips, it can happen that the solder overflows significantly into the gap areas of the package. In addition, chip corners and chip edges can show inadequate properties with regard to the formation of the meniscus structure and oozing out control. The parasitic phenomena described can also lead to further undesirable effects, such as delamination of the molding compound.

[0081] According to an exemplary embodiment, a component for a package and a package formed based on such a component are provided, which show favorable characteristics in the formation of a meniscus structure, exudation control and corner coverage. When connecting components of the package (such as a lead frame structure and a semiconductor chip), a connecting medium (such as solder or assembly adhesive) applied to the surface of a wettability layer of at least one of the components can be used. The wettability layer (also represented as a wetting layer) can be made of a material that promotes the wetting of the wettability layer by a connecting medium. At the same time, the spatial limit of the wettability layer should define the spatial limit that the connecting medium should not (at least should not excessively) flow beyond. Beneficially, the wettability layer of the component and the package according to the exemplary embodiment may include a lateral periphery that may be at least partially concave. Advantageously, the concave edge of such a wettability layer can reliably prevent the connecting medium from undesirably penetrating into an unwanted area, and can enhance appropriate component corner coverage by the connecting medium during the connection process. Simulations and experiments show that the measures can provide a package with excellent reliability.

[0082] Descriptively speaking, the concave edge (which may be curved smoothly or continuously in a stepless manner, or even more preferably, bend discontinuously in steps along the entire concave edge trajectory) may pull the connecting medium inwardly, particularly in the retracted central edge portion between the corners. Further advantageously, the corners defined between adjacent concave edges may pull the connecting medium outwardly into the corner region. Beneficially, this may result in less seepage of the connecting medium beyond the edges while ensuring coverage of the corners with the connecting medium. Covering the corners with the connecting medium may prevent local overheating and burning due to incomplete coverage of the corners by the connecting medium.

[0083] More specifically, a concave silver plating can be applied to a lead frame (as an example of a component) below a chip (as an example of an additional component). Preferably, but not necessarily, the concave edge shape of the wettability layer can be formed to have a stepped profile. Advantageously, forming a concave wettability layer (preferably by silver plating) can allow (1) forming a stable meniscus structure and (2) reliably preventing seepage both at the chip corners and at the chip edges. In a preferred embodiment, forming a concave wettability layer (e.g., by silver plating) can be performed to prevent solder seepage. For example, such an embodiment can be applied to solder-based die attachment, i.e., an application in which the additional component is a semiconductor chip. In particular, exemplary embodiments can allow large chips to be soldered to a lead frame without excessive solder seepage, while ensuring appropriate corner coverage using a solder-type connection medium.

[0084] As mentioned, the silver plated wettability layer on the lead frame can have a concave edge shape. The silver plated layer can preferably be shaped into a stepped concave profile, rather than a smooth concave curve (which may be possible in other embodiments). This has three purposes: First, this can promote complete wetting of the chip corners by controlling seepage around the chip corners. Second, this can prevent seepage at the chip edge due to changes in wettability (because silver has a higher wettability than many other materials such as copper). Third, taking the above measures can promote degassing. Because the stepped profile locally increases the surface tension, easier degassing can be achieved.

[0085] The exemplary embodiments can be particularly advantageously applied to large chips (particularly chips with a size greater than 15 mm). 2 surface area) and / or a power package with a small gap to the edge of the lead frame.

[0086] Figure 1 1 shows a three-dimensional view of a package 100 according to an exemplary embodiment. Figure 1 The package 100 may be implemented as a semiconductor power package.

[0087] The package 100 shown includes a component 102, which is implemented here as a lead frame structure. The lead frame structure includes a die pad 150, which provides a mounting area for mounting an exposed die thereon. The die pad 150 forms a functional body 108 of the component 102, because the die pad 150 provides the function of mounting an exposed die thereon. In addition, the lead frame structure may include one or more lead structures 152, 154 separated from the die pad 150, and each lead structure 152, 154 includes one or more leads for contacting the die terminal after encapsulating the package 100. The die pad 150 may also include integrally formed leads 156. For example, the lead frame structure may be implemented as a patterned copper plate.

[0088] As shown, a wetting layer 110 (which may also be denoted as a wetting layer) is disposed on the upper major surface of the functional body 108. The wetting layer 110 may be implemented as a patterned silver plating. The wetting layer 110 is configured to facilitate solder-type (or alternatively assembly-type) connection media ( Figure 1 Not shown, see Figure 3 Such a connecting medium 112 is to be applied on the wettability layer 110 for connecting the bottom side lead frame type component 102 of the package 100 with the top side semiconductor chip type further component 104 .

[0089] As mentioned, the further component 104, which is implemented here as a power semiconductor transistor chip, also forms part of the package 100. In the example shown, the further component 104 is implemented as a field effect transistor chip having a source pad 158, a drain pad (not shown) and a gate pad 160. As shown, the source pad 158 and the gate pad 160 are both arranged on the upper main surface of the further component 104. The drain pad is arranged on the lower main surface of the further component 104, so that Figure 1 During operation the transistor chip is configured for vertical current flow.

[0090] The bottom major surface of the further component 104 is connected to the top major surface of the component 102 via the connection medium 112 on the wettability layer 110. Thus, the drain pad becomes electrically accessible via one or more leads 156. The source pad 160 may also be electrically coupled to a designated lead structure 152, for example, by a connecting wire (not shown).

[0091] In addition, according to Figure 1 The package 100 comprises a third component 106, which is implemented as a metal clip. The bottom main surface of the third component 106 is connected to the metal clip by another connecting medium ( Figure 1 The lead structure 154 is connected to the source pad 158 at the top main surface of the further component 104 by a lead structure (not shown in the figure), such as solder. The connection can be supported, for example, by providing an additional wettability layer (not shown) on the bottom main surface of the third component 106. Since the end section of the further component 106 is connected to the lead structure 154, the source pad 158 can be powered from the outside of the package 100 through the lead structure 154 after encapsulation.

[0092] although Figure 1 1, but a portion of component 102, the entire additional component 104, the entire third component 106, and a portion of lead structures 152, 154 may be encapsulated by an encapsulation material (not shown). After encapsulation, leads electrically coupled to source pad 158, drain pad 160 may be connected from outside of the encapsulation material for connection with peripheral electronic devices of package 100. For example, the encapsulation material may be a molding compound.

[0093] In order to obtain a package 100 with high reliability, a specific design of the wettability layer 110 between the components 102, 104 (and / or between the components 104, 106) may be very advantageous, as described below: Figure 1 As shown partially in FIG. 1 , the wettability layer 110 has a lateral periphery with a completely concave edge 114. This design Figure 1114 is shown in full for two edges 114 and partially for the third edge 114, but according to Figure 1 , may also be present at each of the four edges 114 of the wettability layer 110 on the component 102. Thus, the wettability layer 110 shown has a concave edge 114 along its entire lateral perimeter. In addition, Figure 1 Detail 164 is shown showing an edge 114 having a stepped concave design according to a preferred embodiment. More specifically, the wettability layer 110 is shown having a concave edge 114 along each of the four sides of its generally but not completely rectangular lateral perimeter with a stepped concave notch in each edge 114.

[0094] In the preferred embodiment shown, each concave edge 114 can be implemented as a stepped concave edge having a plurality of steps 116. Referring again to detail 164, a virtual curved track 166 connecting the corners 118 between adjacent edges 114 and the inner step corners defined by the steps 116 is shown compared to a hypothetical rectangular wettability layer profile 168. In addition, the stepped concave edge 114 forms a Figure 1 164. Referring now to another detail 172, the step 116 is defined by an inner step angle β and an outer step angle β, which may be in the range of 45° to 135°, and in the illustrated embodiment employs a preferred value of 90°. The inner step angle and the outer step angle may have the same or different angle values. Different inner step angles may have the same or different angle values. Different outer step angles may have the same or different angle values. The concave edge 114 shown in detail 164 is formed at one side of the lateral periphery between two corners 118 having adjacent edges 114. As shown, the recess of the concave edge 114 leads to an innermost central edge portion 120 between two corners 118 forming an outermost edge region. In the illustrated embodiment, the concave edge 114 has four steps 116. Alternatively, each edge 114 may have any other—preferably even—number of steps 116 , such as two or six steps 116 at the respective edge 114 .

[0095] The described design of the wettability layer 110 with the concave step edge 114 has the following advantages: On the one hand, this can inhibit the undesired penetration of the connection medium 112 into undesired areas that significantly exceed the limits of the wettability layer 110. In addition, the described design of the wettability layer 110 can facilitate the proper covering of the corners 118 with the connection medium 112 during the connection process. Therefore, the described edge design of the wettability layer 110 can allow the manufacture of the package 100 with high mechanical and electrical reliability. Figure 1The stepped concave silver plating of the leadframe-type component 102 can result in a stable meniscus structure. In addition, a reliable protection against leakage of the connection medium 112 can be achieved, in particular in the innermost central edge portion 120 of the edge 114. Thus, significant advantages can be achieved both at the chip corners and at the chip edges of the semiconductor chip shown as a further component 104. The design shown and described can allow even large chips to be reliably soldered to the leadframe. This can achieve the use of a solder-type connection medium 112 without excessive solder leakage and with significant coverage of the corners.

[0096] Figure 2 A top view of a conventional package 200 having a connection medium 204 thereon is shown according to a simulation.

[0097] in short, Figure 2 A lead frame 202 is shown covered with a rectangular wettability layer 206 on which a solder type connection medium 204 is applied for connecting a semiconductor chip 208 on top of the lead frame 202. On top of the semiconductor chip 208, a metal clip 214 is attached.

[0098] More specifically, Figure 2 A simulation of the soldering process of a package 200 with a conventional rectangular plating is shown. In some areas, a large amount of solder overflow occurs, see reference numeral 210. As a result, severe oozing of the connection medium 204 may occur at the chip edge. Incomplete chip corner coverage may also occur, as shown by reference numeral 212 (see details 216 in particular).

[0099] Figure 3 A top view of a simulated package 100 according to an exemplary embodiment is shown.

[0100] like Figure 3 As shown by arrow 176 in FIG. 1 , the stepped concave edge 114 can pull the connecting medium 112 inward and focus on the retracted central edge portion between the corners 118 (see Figure 1 120 in the figure). Advantageously, this can effectively suppress the connection medium 112 from seeping out of the edge 114. The corners 118 between the stepped concave edges 114 preferably have a corner angle α in the range of 80° to 100°, preferably 90°, which can pull the connection medium 112 outward in the area adjacent to the corners 118, see arrow 178 (especially in detail 180). As a result, excessive heating due to the corners 118 not being completely covered by the connection medium 112 can also be prevented, because the described corner design can achieve a significant coverage of the corners with the connection medium 112.

[0101] therefore, Figure 31 shows simulation results of manufacturing a package 100 according to an exemplary embodiment that implements a concave stepped silver plating for forming a wettability layer 110. More specifically, a soldering process is simulated during which a solder-type connecting medium 112 is applied to the wettability layer 110 for connecting a semiconductor die-type additional component 104 to a lead frame structure-type component 102. Figure 3 As shown, improved chip corner coverage can be achieved. In addition, no excessive oozing out occurs at the chip edge. Descriptively speaking, the wettability layer design has the effect of pulling back the solder to prevent oozing out. In addition to significantly reduced oozing out, greatly improved corner coverage can also be achieved.

[0102] Figure 4 An image of a conventional package 200 as manufactured is shown.

[0103] The obtained package 200 is the result of experimental tests following a conventional manufacturing method. In particular, a rectangular wettability layer 206 is formed on a lead frame 202. As shown at 220, solder oozing out following the contour of the plating shape of the wettability layer 206 occurs after solder reflow.

[0104] Figure 5 An image of a package 100 fabricated according to an exemplary embodiment is shown.

[0105] according to Figure 5 The package 100 obtained by experiment is based on the formation of a wettability layer 110 having a stepped concave circumferential edge 114 and formed by a silver plating layer. Figure 5 The silver plating design with the concave stepped edge 114 helps to significantly reduce solder oozing out compared to conventional designs.

[0106] Figure 6 A top view of a component 102 for a package 100 according to an exemplary embodiment is shown.

[0107] according to Figure 6 Examples and Figure 1 The embodiment of the invention is different in that, according to Figure 6 The concave edges 114 extending along the entire periphery of the planar plated wettability layer 110 are completely smooth, stepless and continuous except for four corners 118 between adjacent edges 114. Therefore, the four concave edges 114 have no steps 116.

[0108] Although Figure 1 The embodiment has certain advantages with respect to the Marangoni effect, but Figure 6 The embodiment of is simple to manufacture because it can be formed with a very simple plating mask.

[0109] Figure 7 Shows a top view of the component 102 of the package 100 according to another exemplary embodiment.

[0110] According to Figure 7 the embodiment of Figure 1 differs from the embodiment of Figure 7 in that, according to Figure 7 , only three concave edges 114 are formed along a part of the periphery of the planar plating wettability layer 110. According to Figure 7 , the fourth edge 184 defining the wettability layer 110 is straight. Such a straight edge 184 may be sufficient when the gap distance D between the corresponding edge 184 and the outer edge of the component 102 is large enough. As described above, when the gap distance between the corresponding edge 114 and the outer edge of the component 102 is small (d < D), it may be advantageous to form the corresponding edge 114 with a stepped concave profile.

[0111] Figure 8 Shows a top view of the package 100 according to another exemplary embodiment.

[0112] In Figure 8 the embodiment, the shown package 100 includes a plurality of additional components 104 (e.g., semiconductor chips of different sizes) attached to the same component 102, e.g., on the same lead frame type die pad. In the region where the gap distance is small (d), the edge 114 of the corresponding wettability layer 110 can be formed to have a concave shape. In one or more other regions where the gap distance is large (D > d), one or more edges 184 of the corresponding wettability layer 110 can be formed to have a straight shape.

[0113] Fig. 9 Shows a cross-sectional view of the package 100 according to yet another exemplary embodiment. Briefly, according to Fig. 9 the package 100 involves a stack of components 102, 104, 106, 122, wherein every two adjacent components 102, 104, 106, 122 can be connected by a connection medium 112 and a wettability layer 110 that can have a concave profile. The number of stacked components 102, 104, 106, 122 can be greater than or less than four. The wettability layer 110 can be a plating, e.g., made of silver when formed on a lead frame type component, or made of palladium when formed on a chip type component. For example, the connection medium 112 can be a metal or alloy type solder or a resin-based assembly adhesive.

[0114] More specifically, according to Fig. 9The package 100 includes a bottom side component 102 covered by a wettability layer 110 and configured as a lead frame structure including a die pad 190 and a lead structure 192 .

[0115] The further component 104, which may be a semiconductor power chip, comprises a wettability layer 110 on both its bottom side and top side. The further component 104 is connected to the die pad 190 of the component 102 via a connecting medium 112 therebetween, which wets the connected wettability layer 110. The further component 104 may also be coupled to the lead structure 192 via a connecting wire 194.

[0116] The third component 106, which may be a metal clip, may be connected to the further component 104 via a further connecting medium 112 on the further concave wettability layer 110, as described above. The clip-type component 106 may also be connected directly to the component 102, for example also by welding.

[0117] The fourth component 122, which may be a further semiconductor die, may be connected to the third component 106 via an additional connection medium 112. For this purpose, the third component 106 and / or the fourth component 122 may be provided with a concave wettability layer 110, as described above.

[0118] Fig.10 Different views of components of package 100 are shown according to an exemplary embodiment. Fig.11 Shown by Fig.10 A top view of a package body 100 formed of components. Fig.12 Shown is the Fig.10 and Fig.11 A three-dimensional view of a detail of a component 102 of the package 100 .

[0119] The package 100 shown comprises a patterned metal plate as a leadframe structure constituting a component 102. The leadframe structure comprises a die pad which forms a functional body 108 of the component 102, in that the functional body 108 is designed for mounting thereon a further component 104 in the form of a semiconductor chip (which may be of the type that experiences a vertical current flow during operation of the package 100). The leadframe structure type component 102 has connected or connectable leads 156 (which are only schematically shown and may have any desired configuration). The further component 104 may cooperate with other package sections 191, 193 such as further semiconductor chips or the like.

[0120] The wettability layer 110 is formed on the upper main surface of the functional body 108 and can be implemented as a patterned silver plating. During the soldering process, the wettability layer 110 promotes wetting of the solder as the connecting medium 112 (see Fig.13 ). The connecting medium 112 can be sandwiched between the wettability layer 110 of the semiconductor chip-type additional component 104 and the exposed conductive connection layer 135. The exposed conductive connection layer 135 forms the metallization layer of the additional component 104. In particular, the conductive connection layer 135 can form the front side metallization of the semiconductor chip. For example, there can be an entire source pad on the exposed conductive connection layer 135, and the gate pad can be invisible, because in SFET9 technology, there can be wiring inside the silicon chip so that the gate and sense pads can be relocated to the back side. More generally, the conductive connection layer 135 should not be limited to the front side metallization or the back side metallization. The conductive connection layer 135 can be on the side of the semiconductor chip-type additional component 104 to be attached to the lead frame or carrier-type component 102.

[0121] In addition, according to Fig.11 The package 100 may include a third component 106 such as a metal clip (see Fig.14 and Fig.15 ). The third component 106 can electrically connect a further metallization layer of the further component 104 on a main surface of the further component 104 facing away from the wettability layer 110 of the carrier component 102 .

[0122] although Figure 1 Not shown, but a portion of component 102, at least a portion of further component 104, at least a portion of third component 106, and a portion of lead 156 may be encapsulated by an encapsulation material such as a molding compound (not shown).

[0123] according to Figures 10 to 12 , the lateral periphery has a concave edge 114 on two opposite sides of the wettability layer 110. One of the two opposite sides having the concave edge 114 has one concave notch 131, while the other side has three concave notches 131. In the example shown, the other two remaining sides of the generally rectangular wettability layer 110 do not have concave notches 131, but are straight.

[0124] Furthermore, optionally, the die pad type functional body 108 on which the wettability layer 110 is formed may also have a lateral periphery having a concave edge 133 following the concave contour of the concave edge 114 of the wettability layer 110 .

[0125] For the sake of clarity, it should be said that the mentioned shape of the die pad is optional and can be omitted to further reduce the workload of manufacturing the die pad. In the case where the shape of the die pad is omitted, the silver plating with the concave shape may be sufficient.

[0126] More specifically, the lateral periphery on two opposite sides of the functional body 108 may have a concave edge 133. One of the two opposite sides having the concave edge 133 has one concave notch, while the other side has three concave notches. As shown, the entire lateral periphery of the wettability layer 110 is located inside the entire lateral periphery of the functional body 108. Therefore, the area of ​​the main surface of the functional body 108 is greater than the area of ​​the wettability layer 110. This allows for appropriate mechanical support of the chip-type additional component 104.

[0127] Likewise Fig.10 As shown, the further component 104 implemented as a semiconductor chip has an exposed conductive connection layer 135 as a (e.g. front side) metallization for connection to the wettability layer 110 via a connection medium 112 such as solder. The conductive connection layer 135 may refer to a metallization layer of the chip-type further component 104, which will be attached to the die pad-type component 102. Whether the conductive connection layer 135 is made by a front side metallization process or by a back side metallization process may depend on the manufacturing process of the chip and how the chip is used, i.e. may depend on the desired application. Therefore, the configuration of the conductive connection layer 135 as a front side or back side metallization may be interchangeable depending on the application requirements. In the embodiment shown, flip chip attachment is implemented, but chip attachment may also be selected without flip chip. The exposed conductive connection layer 135 has a lateral periphery with a concave edge 137. According to Fig.10 , the lateral periphery on two opposite sides of the exposed conductive connection layer 135 has a concave edge 137. One of the two opposite sides having the concave edge 137 has one concave notch, while the other side has three concave notches. In the example shown, the other two remaining sides of the exposed conductive connection layer 135 do not have a concave notch, but are straight. Therefore, the concave edge 137 of the exposed conductive connection layer 135 follows the contour of the concave edge 114 of the wettability layer 110. This can promote self-alignment between the functional body 108 and the further component 104 during assembly, see Fig.14 and Fig.15 .

[0128] Furthermore, the concave edge 137 of the exposed electrically conductive connection layer 135 is laterally delimited by an electrically insulating and non-weldable delimiting structure 139 of the further component 104, which is implemented here as an epoxy resin material. For example, the delimiting structure 139 can be arranged along the entire periphery of the exposed electrically conductive connection layer 135 or only along a portion of the exposed electrically conductive connection layer 135. Advantageously, the delimiting structure 139 covers the functionally active structures 141 of the further component 104. These functionally active structures 141 can be electrically active components of the further component 104, which should not be in electrically conductive contact with the connection medium 112. The delimiting structure 139 electrically decouples the functionally active structures 141 from the connection medium 112.

[0129] The exposed conductive connection layer 135 is made of a solderable material such as copper. When the functional body 108 is connected to the other component 104 using the solder type connection medium 112 between the functional body 108 and the other component 104, the connection medium 112 connects the wettability layer 110 to the exposed conductive connection layer 135 but not to the functional active structure 141.

[0130] In conclusion, Figures 10 to 12A package 100 is shown, which comprises a carrier and a semiconductor chip with an electrically conductive connection layer 135. A connection medium 112 may be provided for connecting the electrically conductive connection layer 135 to the carrier. The electrically conductive connection layer 135 may have a lateral periphery, at least a portion of which has a concave edge 137. The package 100 may also include a wettability layer 110, which is arranged on a main surface of the carrier and is configured to promote wetting of a connection medium 112 to be applied on the wettability layer 110, the connection medium 112 being used to connect the electrically conductive connection layer 135 of the semiconductor chip to the carrier. The wettability layer 110 may have a lateral periphery, at least a portion of which has a concave edge 114. At least one side of the lateral periphery of the wettability layer 110 may have a concave edge 114, the concave edge 114 having at least two concave notches 131 in the respective side. The concave edge 137 of the conductive connection layer 135 can follow the contour of the concave edge 114 of the wettability layer 110. At least one side of the lateral periphery of the conductive connection layer 135 can have a concave edge 137, and the concave edge 137 has at least two concave notches in the corresponding side. Therefore, the package 100 can have a semiconductor chip inside, and the bottom side of the semiconductor chip can have a metallization 135, and the metallization 135 has the described special shape. Therefore, the package 100 can include a carrier, a semiconductor chip with the described special shape on the bottom side, and between the carrier and the semiconductor chip can be an adhesive layer or directly a solder layer. In addition, a wettability layer with the characteristics described above can be provided. Therefore, a semiconductor package with the described special pattern metallization 135 on the bottom side can be provided.

[0131] Descriptively speaking, Figures 10 to 12 The embodiments provide irregular matching solderable structures for effective soldering (see reference numerals 110, 135). These features can be applied in lead frame type components 102 and semiconductor chip type additional components 104, specifically, on die pads and corresponding flip-chip low-side chips.

[0132] The additional component 104 may be An SFET type field effect transistor chip having a functional active structure 141 on the top side which needs to be covered by an electrically insulating and non-solderable delimiting structure 139 (e.g. epoxy, glue or mixture). Therefore, the solderable opening is not a regular rectangle or even a square, but an irregular shape in the embodiment shown. shown The design advantageously prevents the solder type connection medium 112 from overlapping with active features covered by epoxy to prevent reliability risks. At the same time, appropriate support for the chip is provided to prevent chip cracking.

[0133] The illustrated embodiment shows The die pad is designed so that the silver plated surface of the die pad matches the pattern of the front-side solderable openings of the chip. The die pad itself follows the contour of the silver plated surface, but can be slightly larger, which also provides better support for the chip to avoid chip cracking.

[0134] One advantageous aspect of the illustrated embodiment can be seen from the following: two similar irregular solderable structures (see reference numerals 110, 135) are provided so that the two can be matched together for effective soldering. The two structures are the silver-plated surface on the island-shaped die pad and the front-side solderable area of ​​the chip with similar contours.

[0135] Figures 10 to 12 The assembly and flip-chip attach configuration of a low-side field effect transistor (LS-FET) and the corresponding solder effective coverage are shown.

[0136] Fig.13 Shows about Fig.11 Simulation results of solder coverage of package 100 .

[0137] The simulated image shows effective solder coverage due to the two similar profiles of the wettability layer 110 and the exposed conductive connection layer 135 .

[0138] Fig.14 A top view of a package 100 ′ (comprising a component 102 ′, a further component 104 ′ and a third component 106 ′) is shown having various commonly occurring assembly problems. Fig.15 A top view of a package 100 according to an exemplary embodiment is shown, wherein the assembly issues are overcome by the automatic alignment functionality of features of the exemplary embodiments. Fig.16 Shows about Fig.15 Simulation results of solder coverage of package 100 .

[0139] In addition to the epoxy of the chip, the exemplary embodiment also ensures that the active features of the chip (see reference numeral 141 as described above) are free from any risk of solder bridging and / or leakage.

[0140] As mentioned above, the irregular shapes of some features also serve as automatic aligners for the chip.

[0141] When flip-chip bonding, the chip may be biased relative to the machine's capabilities ( Fig.14 left and center) and / or rotated ( Fig.14 Right). During reflow, the silver plating and front-side metallization of the chip may have a pulling effect, reducing the amount of bias. Therefore, the active features can be further protected. Fig.15 As shown, undesirable phenomena can be strongly suppressed by the exemplary embodiments.

[0142] Fig.16 It is shown that at only a 5° rotation there is a certain risk of active features overlapping the solder. However, according to the specification, a 5° rotation is already beyond the connection limit.

[0143] 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 component (102) for a package (100), wherein: The component (102) comprises: Function (108); and a wettability layer (110) arranged on a main surface of the functional body (108) and configured to promote wetting of a connecting medium (112) to be applied on the wettability layer (110), the connecting medium (112) being used to connect the component (102) to a further component (104) of the package (100); · wherein the wettability layer (110) has a lateral periphery, and at least a portion of the lateral periphery has a concave edge (114).

2. The component (102) according to claim 1, wherein The component (102) is configured as one of: a lead frame structure; a clip; and an electronic component, such as a semiconductor chip.

3. The component (102) according to claim 1 or 2, wherein: The wettability layer (110) is a plating layer.

4. The component (102) according to claim 3, wherein The component (102) includes one of the following features: When the component (102) is configured as a lead frame structure or a clip, the plating includes or consists of silver; When the component (102) is configured as an electronic component, such as a semiconductor chip, the plating layer includes or consists of one of the following group, the group consisting of: palladium, gold, titanium, nickel and NiNiP.

5. The component (102) according to any one of claims 1 to 4, wherein: The wettability layer (110) has the concave edge (114) along its entire lateral periphery.

6. The component (102) according to any one of claims 1 to 5, wherein: The wettability layer (110) has the concave edge (114) along each of the four sides of its generally rectangular lateral periphery.

7. The component (102) according to any one of claims 1 to 6, wherein: The concave edge (114) is a stepped concave edge (114) having a plurality of steps (116).

8. The component (102) according to claim 7, wherein The step (116) is defined by a step angle (β) in the range of 45° to 135°, for example in the range of 60° to 120°, preferably in the range of 80° to 100°.

9. The component (102) according to any one of claims 1 to 8, wherein: At least a portion of the concave edge (114) is formed at one side of the lateral periphery between two corners (118), the concave portion of the concave edge (114) leading to an innermost central edge portion (120) between the two corners (118).

10. The component (102) according to claim 9, wherein The concave edge (114) has at least two steps (116), such as at least four or at least six steps (116), along the one side.

11. The component (102) according to any one of claims 1 to 10, wherein: At least one side of the lateral periphery of the wettability layer (110) has a concave edge (114), and the concave edge (114) has at least two concave notches (131) in the corresponding side.

12. The component (102) according to any one of claims 1 to 11, wherein: The functional body (108) has a lateral periphery, at least a portion of which has a concave edge (133) that follows the concave contour of the concave edge (114) of the wettability layer (110).

13. The component (102) according to claim 12, wherein The functional body (108) includes a die pad or consists of a die pad.

14. The component (102) according to claim 12 or 13, wherein: The entire lateral periphery of the wettability layer (110) is located inside the entire lateral periphery of the functional body (108), so that the area of ​​the main surface of the functional body (108) is larger than the area of ​​the wettability layer (110).

15. A package (100), wherein: The package (100) comprises: · a component (102) according to any one of claims 1 to 14; Additional components (104); and · connection medium (112); The further component (104) is connected to the component (102) via the connecting medium (112) on the wettability layer (110).

16. The package (100) according to claim 15, wherein: The connecting medium (112) includes solder.

17. The package (100) according to claim 15 or 16, wherein: The connecting medium (112) includes an assembly adhesive.

18. The package (100) according to any one of claims 15 to 17, wherein: The component (102) is a chip carrier, for example a lead frame structure, and the further component (104) is an electronic component, for example a semiconductor chip.

19. The package (100) according to any one of claims 15 to 17, wherein: The component (102) is a clip and the further component (104) is an electronic component, such as a semiconductor chip.

20. The package (100) according to any one of claims 15 to 19, wherein: The package (100) comprises a third component (106) and a further connecting medium (112), wherein the third component (106) is connected to the further component (104) via the further connecting medium (112) located on the further component (104) and / or on a further wettability layer (110) of the third component (106), the further wettability layer (110) having a lateral periphery, at least a portion of which has a concave edge (114).

21. The package (100) according to claim 20, wherein: The package (100) comprises a fourth component (122) and a third connecting medium (112), wherein the fourth component (122) is connected to the third component (106) via the third connecting medium (112) located on the third component (106) and / or on a third wettability layer (110) of the fourth component (122), wherein the third wettability layer (110) has a lateral periphery, and at least a portion of the lateral periphery has a concave edge (114).

22. The package (100) according to claim 20 or 21, wherein: The component (102) is a chip carrier, the further component (104) is a semiconductor chip, and the third component (106) is a clip.

23. The package (100) according to claim 22, wherein: The fourth component (122) is another semiconductor chip.

24. The package (100) according to any one of claims 15 to 23, wherein: The further component (104) has an exposed electrically conductive connecting layer (135) for connecting to the wettability layer (110) via the connecting medium (112), the exposed electrically conductive connecting layer (135) having a lateral periphery, at least a portion of which has a concave edge (137).

25. The package (100) according to claim 24, wherein: The concave edge (137) of the exposed conductive connection layer (135) follows the contour of the concave edge (114) of the wettability layer (110).

26. The package (100) according to claim 24 or 25, wherein: At least a portion of the concave edge (137) of the exposed electrically conductive connecting layer (135) is laterally delimited by an electrically insulating and / or non-solderable delimiting structure (139) of the further component (104).

27. The package (100) according to claim 26, wherein: The delimiting structure (139) covers, in addition to the exposed electrically conductive connection layer (135), also the functionally active structure (141) of the further component (104).

28. The package (100) according to any one of claims 24 to 27, wherein: The exposed conductive connection layer (135) is made of a solderable material.

29. The package (100) according to any one of claims 24 to 28, wherein: The further component (104) is a semiconductor chip, and its exposed electrically conductive connection layer (135) is a chip metallization layer.

30. The package (100) according to claim 29, wherein: The semiconductor chip experiences vertical current flow during operation of the package (100).

31. The package (100) according to claim 29 or 30, wherein: The chip metallization layer is a front-side metallization or a back-side metallization.

32. A method for manufacturing a package (100), wherein: The method comprises: arranging a wettability layer (110) on a major surface of a functional body (108) of a component (102), for promoting the wetting of a connecting medium (112) to be applied on the wettability layer (110); forming the wettability layer (110) with a lateral perimeter, at least a portion of the lateral perimeter having a concave edge (114); Applying the connecting medium (112) on the wettability layer (110); and The component (102) is connected to another component (104) via the connecting medium (112).

33. A package (100), comprising: ·Carrier; A semiconductor chip having an electrically conductive connection layer (135); as well as A connecting medium (112) connecting the electrically conductive connecting layer (135) to the carrier; ·Wherein, the conductive connection layer (135) has a lateral periphery, and at least a portion of the lateral periphery has a concave edge (137).

34. The package (100) according to claim 33, wherein: The package (100) comprises: a wettability layer (110) arranged on a major surface of the carrier, and is configured to promote wetting of a connecting medium (112) to be applied on the wettability layer (110), the connecting medium (112) being used to connect an electrically conductive connecting layer (135) of the semiconductor chip to the carrier; · wherein the wettability layer (110) has a lateral periphery, and at least a portion of the lateral periphery has a concave edge (114).

35. The package (100) according to claim 34, wherein: At least one side of the lateral periphery of the wettability layer (110) has a concave edge (114), and the concave edge (114) has at least two concave notches (131) in the corresponding side.

36. The package (100) according to claim 34 or 35, wherein: The concave edge (137) of the conductive connection layer (135) follows the contour of the concave edge (114) of the wettability layer (110).

37. The package (100) according to any one of claims 33 to 36, wherein: At least one side of the lateral periphery of the conductive connection layer (135) has a concave edge (137), and the concave edge (137) has at least two concave notches in the corresponding side.

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