Manufacturing a package using a solderable or sinterable metallic interconnect structure applied to a sacrificial substrate and package

Abstract

A method for producing a package (100), wherein the method comprises: • Applying a metallic interconnect structure (102) comprising a solder or sinter material to a sacrificial support (108); • Mounting an electronic component (104) onto the metallic connecting structure (102); • Encapsulating at least part of the electronic component (104) and the metallic interconnect structure (102) with an encapsulation (106); • then removal of the sacrificial support (108) in order to expose at least part of the metallic connection structure (102); and • Formation of an intermetallic compound (112) in the metallic compound structure (102) at an interface with the sacrificial carrier (108) by means of diffusion or migration of material from the sacrificial carrier (108) into the metallic compound structure (102).

Description

Background Technical field

[0001] Different embodiments generally relate to a package and a method for manufacturing a package. Description of the state of the art

[0002] A conventional electronic system may have an electronic component which is soldered onto a chip carrier, for example a conductor frame, and may optionally be encapsulated using a molding compound.

[0003] US 2020 / 0203243A1 describes a microelectronic device. The microelectronic device comprises a chip 203 mounted on an electrically insulating layer 227 made of silicon dioxide, silicon nitride, or polyimide (see paragraph 47). In addition to the chip 203 and the electrically insulating layer 227, intermediate pads 207 made of metal are arranged (see paragraph 40). These intermediate pads 207 contain a base layer, for example, of copper, and a barrier layer designed to reduce the diffusion of copper and tin into the intermediate pads 207 during a subsequent soldering step (see paragraph 40). Fig. 2J shows the intermediate pads 207 and the solder joints 230 mentioned above with package leads 221 (see also paragraph 50). Summary

[0004] There may be a need to manufacture a package in a simple and efficient manner with high performance.

[0005] According to an exemplary embodiment, a method for manufacturing a package is provided, wherein the method comprises applying a metallic interconnect structure comprising a solder or sintering material to a sacrificial carrier, mounting an electronic component on the metallic interconnect structure, encapsulating at least a part of the electronic component and the metallic interconnect structure with an encapsulation, then removing the sacrificial carrier to expose at least a part of the metallic interconnect structure, and forming an intermetallic connection in the metallic interconnect structure at an interface with the sacrificial carrier by means of diffusion or migration of material from the sacrificial carrier into the metallic interconnect structure.

[0006] According to another exemplary embodiment, a package is provided which has a metallic interconnect structure, an electronic component mounted on the metallic interconnect structure, and an encapsulation which encapsulates at least part of the electronic component and the metallic interconnect structure, wherein an exposed part of the metallic interconnect structure has an intermetallic connection.

[0007] According to an exemplary embodiment, simple and efficient package fabrication can be achieved by depositing a solderable or sinterable metallic interconnect structure onto a sacrificial or temporary support, which is subsequently removed before the completion of the fabrication process. After mounting an electronic component onto the deposited metallic interconnect structure and subsequent encapsulation to securely hold the parts together, the sacrificial support can be removed to expose the metallic interconnect structure, at least partially. This exposure process can simplify the subsequent electrical and mechanical coupling of the package to electronic peripherals. The aforementioned fabrication process can ensure a compact design of the manufactured package, since the sacrificial support can be removed, resulting in a supportless package with small dimensions.

[0008] Advantageously, an intermetallic connection can be formed as an interface between the sacrificial substrate and the solderable or sinterable metallic connection structure if the sacrificial substrate comprises or consists of a metallic material. Such an intermetallic connection can be exposed in the finished package and can facilitate an electrical and mechanical connection of the package to an electronic peripheral, for example, a printed circuit board. Intuitively, the presence of the intermetallic connection can be a hallmark of embodiments of the manufacturing process described above, provided a suitable metallic sacrificial substrate is implemented. Description of further exemplary embodiments

[0009] Further exemplary embodiments of the method and the package are explained below.

[0010] In the context of the present application, the term "package" can, in particular, refer to an electronic device comprising one or more electronic components which are at least partially encapsulated. For example, such a package can be a module.

[0011] In the context of the present application, the term "metallic interconnection structure" may, in particular, refer to any metallic structure capable of directly or indirectly establishing a mechanical and / or electrical connection between the package and an electronic peripheral, for example, a mounting base (e.g., a printed circuit board). For example, a metallic interconnection structure may comprise a solder material, a sintered material, an electrically conductive adhesive, or any other metallic medium with interconnectivity capabilities.

[0012] In the context of the present application, the term "metallic connection structure comprising a solder or sintering material" may, in particular, refer to a metallic connection structure capable of producing a soldered or sintered joint. A soldering material may be a fusible metal alloy used to create a permanent connection between metallic elements. The soldering material can be melted so that, after cooling, it adheres to and joins the metallic elements. Thus, a soldering material may be an alloy suitable for soldering and may have a lower melting point than the metallic elements being joined. A sintering material may refer to a material suitable for producing a connection between metallic elements by means of sintering.Sintering can refer to the process of compacting and forming a solid mass of material using heat and / or pressure without melting it to its liquefaction point. During sintering, atoms in the material can diffuse across particle boundaries, fusing the particles together to form a solid piece. A soldering material may consist of granules.

[0013] In the context of the present application, the term "sacrificial support" can, in particular, refer to a temporary support structure on which a metallic interconnect structure and at least one electronic component can be assembled prior to encapsulation. After encapsulation, the sacrificial support can be partially or completely removed or sacrificed, so that no material or not all of the material of the sacrificial support forms part of the finished package.

[0014] In the context of the present application, the term "electronic component" may include, in particular, a semiconductor chip (especially a power semiconductor chip), an active electronic device (for example, a transistor), a passive electronic device (for example, a capacitance, an inductor, or a resistor), a sensor (for example, a microphone, a light sensor, or a gas sensor), an actuator (for example, a loudspeaker), and a microelectromechanical system (MEMS). However, in other embodiments, the electronic component may also be of a different type, for example, a mechatronic element, in particular a mechanical switch, etc.

[0015] In the context of the present application, the term "encapsulation" can, in particular, refer to a substantially electrically insulating and preferably thermally conductive material that surrounds at least part of an electronic component, at least part of a metallic interconnect structure, and / or at least part of a sacrificial substrate. For example, the encapsulation can be a molding compound and can be produced, for example, by injection molding. Alternatively, the encapsulation can be a potting compound formed by casting.

[0016] In the context of the present application, the term "intermetallic compound" can, in particular, refer to a composite material that reliably joins the component and the support and comprises a plurality of different metallic constituents. For example, such an intermetallic compound may be formed from a solderable or sinterable material (which, for example, contains tin) and at least one additional metal (for example, copper) originating from a metallic sacrificial support. For example, an intermetallic compound may be a mixture of at least two different intermetallic materials, for example, tin, palladium, gold, silver, nickel, and / or copper. For example, the intermetallic compound may form an intermetallic network structure, i.e., a network of metallic structures made of different metallic materials in a metallic matrix.

[0017] In one embodiment, the method includes the provision of a sacrificial carrier that is temperature-stable up to at least 300 °C. This can ensure that the sacrificial carrier can withstand a reflow process for treating the solder or sintered material of the metallic connection structure and / or an injection molding process.

[0018] In one embodiment, the method includes providing the sacrificial support as one of the group comprising a strip, a plate, and a frame. The sacrificial support can be planar. Providing a planar strip, plate, or frame as the sacrificial support can simplify the manufacturing process.

[0019] In one embodiment, the method includes the provision of a sacrificial substrate, which comprises a metal (particularly copper) and / or a ceramic. For example, the substrate has a conductor frame structure (for example, made of copper). Thus, the sacrificial substrate can be embodied as a structured metal plate and consequently in a simple and easily processable manner. However, the sacrificial substrate can alternatively be embodied in a different way, for example, as a central electrically insulating and thermally conductive layer (for example, made of a ceramic) which is covered on one or both of its opposing main surfaces with an electrically conductive layer (for example, a copper or aluminum layer). For example, a sacrificial substrate can be embodied as a DAB (Direct Aluminum Bonding), DCB (Direct Copper Bonding) substrate, etc. Furthermore, the sacrificial substrate can also be configured as an Active Metal Brazing (AMB) substrate.

[0020] In one embodiment, the method comprises the application of the metallic interconnect structure by means of at least one of the group, comprising deposition and printing, in particular screen printing, screen printing, or inkjet printing. Preferably, the metallic interconnect structure can be printed as one or more pads onto the sacrificial substrate. Screen printing can refer to a process of depositing a metallic interconnect structure, for example, a solder paste or a sintering paste, onto the sacrificial substrate to establish an electrical connection with one or more subsequently mounted electronic components. Stencil printing can refer to a printing technique in which a mesh is used to transfer a metallic interconnect structure onto the sacrificial substrate, except in areas that are made opaque to the metallic interconnect structure by means of a barrier screen.A blade or squeegee can be moved across the stencil to fill the open mesh openings with the metallic compound during printing. Inkjet printing can refer to a printing process that creates an image from the printed material by propelling droplets of an ink-like metallic compound onto the substrate.

[0021] In one embodiment, the method involves mounting the electronic component onto the metallic connection structure by means of at least one component contact. Such a component contact can be an electrically conductive structure that serves as a component interface for sending and / or receiving signals or electrical energy. For example, such component contacts can comprise at least one metal column (for example, a copper column), at least one metal protrusion or a metal sphere, and / or at least one metal pad (in particular with a circular or rectangular geometry).

[0022] In one embodiment, the method involves inserting the at least one component contact into the metallic connection structure. In particular, the at least one component contact can be pressed or immersed into the metallic connection structure, which is still in a deformable state, for example, as a paste. This can make it possible to establish a reliable, large-area electrical connection between the electronic component and the metallic connection structure.

[0023] In one embodiment, the method involves readjusting the profile of the metallic connection structure after assembly. Following the deposition or printing process for applying the metallic connection structure to the sacrificial substrate, at least one physical property of the metallic connection structure can be adjusted by a specific treatment of the metallic connection structure. For example, the readjustment can involve reshaping the metallic connection structure.

[0024] In one embodiment, the method comprises readjusting the profile of the metallic connection structure by means of at least one process from the group, comprising a curing process, a reflow process, and diffusion bonding. In particular, the process of readjusting the profile of the metallic connection structure may involve heating to an elevated temperature, for example, above 200 °C. For example, the reflow process may be reflow soldering if the metallic connection structure is a solder structure. In particular, reflow soldering may refer to a process in which a solder paste (i.e., an adhesive mixture of a powdered solder material and a flux) is used to form a connection with the at least one electronic component. By subjecting the preform of the package to controlled heat, the solder paste remelts to a molten state, producing permanent solder joints.Diffusion bonding can refer to a solid-state welding technique for joining different metallic structures. Diffusion bonding can be based on solid-state diffusion, whereby the atoms of two solid metallic surfaces permeate each other at an elevated temperature below the melting point of the materials involved.

[0025] In one embodiment, the method involves readjusting the profile of the metallic interconnect structure by selectively thickening it locally in a connection area to the at least one electronic component. Specifically, the readjustment can involve adjusting the profile so that there is a thicker metallic interconnect section between the sacrificial carrier and an electrically conductive component contact of the electronic component, compared to a thinner metallic interconnect elsewhere. This can improve the electrical reliability of the manufactured package. Consequently, the metallic interconnect structure can be locally thickened in a connection area to the electronic component. For example, in a cross-sectional view, the metallic interconnect structure is essentially triangular in shape (see, for example, Figure 1). Fig. 1 or Fig. 7).

[0026] In one embodiment, the method involves the formation of an intermetallic compound within the metallic connection structure at an interface with the sacrificial substrate, particularly by means of diffusion or migration of material from the sacrificial substrate into the metallic connection structure. The formation of an intermetallic compound, which includes metallic materials from both the sacrificial substrate and the metallic connection structure, can further improve the reliability of the electrical connection to which the intermetallic compound contributes.

[0027] In one embodiment, the method involves the formation of a dielectric film in an exposed surface region of the metallic compound structure prior to encapsulation. Accordingly, the package can have a dielectric film in a surface region of the metallic compound structure that is covered by the encapsulation. For example, the dielectric film can be a metal oxide layer that forms on an exposed surface of the metallic compound structure during the resetting process described above, particularly when this process is carried out at an elevated temperature in an oxygen atmosphere. Advantageously, such a dielectric film can limit and thereby control the material flow of the heated metallic compound structure during the resetting process.

[0028] In one embodiment, the method involves removing the sacrificial carrier by at least one of the following processes: selective etching, grinding, peeling, and peeling. For example, a copper sacrificial carrier can be removed by selective copper etching. A selective etching process ensures that only material from the sacrificial carrier is removed, and substantially no other materials from the package preform are removed. It is also possible to mechanically remove the sacrificial carrier from the back side of the package preform by back-grinding. Alternatively, the sacrificial carrier can be peeled from the back side in a triggered manner, for example, by pressure and / or elevated temperature. Finally, the sacrificial carrier can be peeled off the rest of the package.

[0029] In one embodiment, the method involves removing the sacrificial support using an intermetallic compound of the metallic connection structure at an interface with the sacrificial support as a stop layer. Advantageously, the intermetallic compound, which contains metallic material from both the sacrificial support and the metallic connection structure, can have a greater hardness than the individual metallic structures involved. Consequently, the intermetallic compound can be highly suitable for functioning as a stop layer to define a stop position where the sacrificial support material removal process halts. This makes process control more precise and simpler.

[0030] In one embodiment, the method involves selectively applying a surface finish to an exposed surface area of ​​the metallic compound structure after removal. For example, a surface finish can be an electrically conductive material configured to protect the metallic compound structure or the intermetallic compound from oxidation. Furthermore, a surface finish can enhance solderability and electrical reliability and performance. For example, such a surface finish can be made of tin or nickel-palladium-gold.

[0031] In one embodiment, the method includes the formation of a structured dielectric protective layer, in particular a solder resist, to expose at least a defined surface area of ​​the metallic connection structure or a surface finish on the metallic connection structure. Advantageously, such a solder resist can be embodied as a lacquer-like polymer film, which is applied to a section of the exposed metallic connection structure or the intermetallic connection to prevent unwanted solder bridges between closely spaced solder pads.

[0032] In one embodiment, the metallic connection structure comprises or consists of a connected granular material, preferably a sinterable granular material. Such an embodiment is described in Fig. 2 shown. In particular, the use of a bonded granular material to form the metallic bonding structure can make it possible to form more square pads and can reduce the risk of short circuits.

[0033] In one embodiment, the package has an electrical connection protrusion, in particular a solder protrusion, which is formed on the intermetallic connection. Such electrical connection protrusions can make it possible to electrically mount the package on a mounting base, for example a printed circuit board, by means of a solder connection or similar intermediate element.

[0034] In one embodiment, the package comprises a plurality of electronic components, each mounted on at least one associated of a plurality of metallic connecting structures. Thus, more than one electronic component can be encapsulated within the package. For example, different electronic components of a common package can be electrically coupled to each other for functional interaction.

[0035] In one embodiment, the electronic component is mounted on a plurality of spatially separated metallic connection structures. Such a configuration allows the electronic components to be electrically connected to a plurality of pads or other types of component contacts in a suitable manner.

[0036] In one embodiment, an active region of the electronic component faces either towards or away from the metallic interconnect structures. An active region of an electronic component can be a region of a semiconductor substrate in which at least one integrated circuit is monolithically integrated. If an active region faces the metallic interconnect structure (see, for example, the flip-chip configuration of Fig. 1) The electrically conductive connection paths can be very short. However, it is also possible that an active area faces away from the metallic connection structure (as in Fig. 16) In such a scenario, an electrical connection between an active area and the metallic connection structure can be formed by means of one or more bond wires or by means of one or more clips.

[0037] In one embodiment, the vertical thickness of the intermetallic compound is in the range of 5 µm to 50 µm, particularly in the range of 10 µm to 30 µm, and further, particularly in the range of 10 µm to 20 µm. Advantageously, the intermetallic compound can be provided with a very small thickness. This keeps the electronic system compact in the vertical direction and ensures the high mechanical, thermal, and electrical reliability of the electronic system.

[0038] In one embodiment, at least one of the at least one electronic component is a bare chip. By embodying the at least one electronic component as an unencapsulated chip, i.e., a pure semiconductor chip without additional dielectric encapsulation, the compactness of the package can be further increased.

[0039] In one embodiment, the electronic system comprises a plurality of (in particular electronic) components mounted on the metallic interconnect structure or on different metallic interconnect structures. Thus, the package can include one or more electronic components (for example, at least one passive component, such as a capacitor, and at least one active component, such as a semiconductor chip).

[0040] In one embodiment, an electronic device is provided which includes the aforementioned package and a mounting base (for example, a printed circuit board, PCB) onto which the package is mounted and electrically coupled. Such a mounting base can be an electronic board that serves as a mechanical base for the package.

[0041] In one embodiment, the package is configured as a power module, for example, an encapsulated power module. For instance, an exemplary embodiment of the electronic system could be an intelligent power module (IPM). Another exemplary embodiment of the package is a dual inline electronic system (DIP).

[0042] In one embodiment, the electronic component is configured as a power semiconductor chip. Thus, the electronic component (for example, a semiconductor chip) can be used for power applications, such as in the automotive sector, and can, for example, include at least one integrated insulated-gate bipolar transistor (IGBT) and / or at least one transistor of another type (for example, a MOSFET, a JFET, etc.) and / or at least one integrated diode. Such integrated circuit elements can be manufactured, for example, using silicon technology or based on wide-bandgap semiconductors (for example, silicon carbide). A semiconductor power chip can include one or more field-effect transistors, diodes, inverter circuits, half-bridges, full-bridges, drivers, logic circuits, other devices, etc.

[0043] A semiconductor substrate, particularly a silicon substrate, can be used as the substrate or wafer that forms the basis of the electronic components. Alternatively, a silicon oxide or other insulator substrate can be provided. It is also possible to implement a germanium substrate or a III-V semiconductor material. For example, exemplary embodiments can be implemented using GaN or SiC technology. Brief description of the drawings

[0044] The accompanying drawings, which are included to provide a deeper understanding of exemplary embodiments and form part of the description, show exemplary embodiments.

[0045] In the drawings: Fig. Figure 1 shows a cross-sectional view of a package according to an exemplary embodiment. Fig. Figure 2 shows a cross-sectional view of a package according to another exemplary embodiment. Fig. 3 to Fig. Figure 10 shows cross-sectional views of structures obtained during the creation of a package, as in Fig. 1 shown, according to an exemplary embodiment. Fig. Figure 11 shows a cross-sectional view of a package according to yet another exemplary embodiment. Fig. 12 to Fig. Figure 14 are top views of structures obtained during the manufacture of packages according to an exemplary embodiment. Fig. Figure 15 shows a cross-sectional view of a package according to yet another exemplary embodiment. Fig. Figure 16 shows a cross-sectional view of a package according to yet another exemplary embodiment. Detailed description

[0046] The representation in the drawing is schematic and not to scale.

[0047] Fig. Figure 1 shows a cross-sectional view of a Package 100 according to an exemplary embodiment.

[0048] Package 100 includes an electronic component 104. For example, the electronic component 104 is a semiconductor chip, for example a semiconductor power chip (in the example a MOSFET chip for power applications).

[0049] The electronic component 104 has component contacts 110 (for example, electrically conductive columns or pads) for providing an electrical contact to integrated circuit elements inside the electronic component 104.

[0050] Each component contact 110 is mounted on and electrically coupled to one of the respective metallic connection structures 102. Thus, various component contacts 110 of the electronic component 104 are mounted on and electrically coupled to an associated plurality of spatially separated metallic connection structures 102. Each metallic connection structure 102 can have a solder material, for example, tin. In the illustrated embodiment, each metallic connection structure 102 has, in the cross-sectional view shown, Fig. 1 essentially a triangular shape. More precisely, each of the metallic connection structures 102 is locally thickened in a connection area to one of the respective component contacts 110 of the electronic component 104. This can improve the reliability of the electrical connection between the connection contacts 110 and the metallic connection structures 102.

[0051] The electronic component 104 is in Fig. 1 is mounted in a flip-chip configuration. Consequently, an active area of ​​the electronic component 104 is located on a lower main surface of the electronic component 104 and is therefore facing the metallic interconnect structures 102. This keeps the electrical connection paths short and contributes to a compact design of the package 100.

[0052] An encapsulation 106 encapsulates the electronic component 104, including its component contacts 110, and encapsulates part of the metallic connection structures 102. For example, the encapsulation 106 can be a molding compound.

[0053] A section of the metallic compound structures 102, which extends beyond the encapsulation 106, exhibits an intermetallic compound 112, embodied as a metal film. The intermetallic compound 112 comprises a solderable material, for example, tin, which forms the remainder of the metallic compound structure 102. Furthermore, the intermetallic compound 112 comprises another metallic material, for example, copper, which is a residue of a temporary copper support (see reference numeral 108 in [reference number]). Fig. 3) is, which was removed from the package 100 before its manufacture was completed. The intermetallic compound 112 has a high hardness, which improves the mechanical reliability of the package 100, promotes the reliable electrical connectivity of the package 100, and additionally facilitates the removal of the sacrificial carrier 108 during a selective etching process (see Fig. 8) can act as a stop layer.

[0054] As in detail 124 in Fig. As shown in Figure 1, the package 100 has a dielectric film 114 in a surface region of each corresponding metallic connection structure 102, which is covered by the encapsulation 106. Advantageously, the dielectric film 114, which may be an oxidized metallic material of the metallic connection structure 102, can limit the solder material flow during the forming of the substantially triangular metallic connection structures 102 during a manufacturing process, as described in more detail below.

[0055] Furthermore, part of the outer surface of the metallic interconnect structures 102 is covered by a surface finish 116, for example nickel-palladium-gold, to protect the electrically conductive surface of the package 100 from oxidation or corrosion. In addition, the package 100 has a structured dielectric protective layer 118, which can be implemented as a solder resist, and which can be used to expose only a defined surface area of ​​the surface finish 116 on the metallic interconnect structures 102. The structured dielectric protective layer 118 prevents unwanted solder bridges and the like. More precisely, the structured dielectric protective layer 118 can define a desired pitch and can eliminate imperfections at the boundary with the pads.

[0056] Due to the removal of the sacrificial carrier 108 before the completion of the fabrication of the package 100, the package 100 is a carrierless package, i.e., it has no carrier. Advantageously, this leads to a compact design of the package 100.

[0057] A method for producing package 100 of Fig. 1 is below with reference to Fig. 3 to Fig. 10 described.

[0058] Fig. Figure 2 shows a cross-sectional view of a Package 100 according to another exemplary embodiment.

[0059] Package 100 according to Fig. 2 differs from Package 100 according to Fig. 1 in particular in that according to Fig. 2 the metallic compound structures 102 are formed from a bonded granular material 122. In other words, the metallic compound structures 102 are of Fig. 2 formed from connected electrically conductive granular particles 126 (which are formed, for example, from sintered material). Advantageously, this can lead to a more square pad shape than in Fig. 1 and can reduce or even minimize the risk of an electrical short circuit during the operation of Package 100.

[0060] Fig. 3 to Fig. Figure 10 shows cross-sectional views of structures obtained during the creation of a package 100, as described in Fig. 1 shown, according to an exemplary embodiment.

[0061] With reference to Fig. 3 A sacrificial carrier 108 is provided as a planar, electrically conductive body, for example as a copper strip. Advantageously, the sacrificial carrier 108 can be made of a material that is temperature-stable at least up to 300 °C to withstand a reflow process (see Fig. 6) and an injection molding process (see Fig. 7) to withstand.

[0062] Thus, it is possible to use a bare copper strip as the sacrificial carrier 108, which keeps manufacturing costs low. The sacrificial carrier 108 can be punched to form index openings (not shown).

[0063] With reference to Fig. 4 A plurality of metallic connection structures 102 are applied to the sacrificial support 108. In Fig. 4. The metallic connection structures 104 have a substantially rectangular cross-sectional shape. For example, the metallic connection structures 102 can comprise a solder or sintering material, such as a solder paste or sintering paste. Such a deformable material for the metallic connection structures 102 can be applied to the sacrificial carrier 108 by deposition or printing. Preferably, the metallic connection structures 102 can be applied by screen printing. Screen printing can be suitable for creating a pitch and size corresponding to an electronic component 104 that is subsequently to be mounted. Thus, the metallic connection structures 102 can be applied by stencil printing of soft materials, such as solder or sintering pads.

[0064] With reference to Fig. In step 5, an electronic component 104, for example a bare chip, is mounted onto the metallic connection structures 102. This allows a chip bonding process to be carried out. More precisely, each of a plurality of component contacts 110 of the electronic component 104 can be inserted into an associated, still deformable, metallic connection structure 102, with direct physical contact between the side walls of the component contacts 110 and the associated metallic connection structure 102. By inserting the component contacts 110 into the metallic connection structures 102, such that contact is established not only on a bottom surface but also on the side wall surfaces of the component contacts 110, a reliable electrical connection between each metallic connection structure 102 and each component contact 110 can be promoted.This can ensure high electrical reliability of the manufactured package 100. For example, each component contact 110 can be a copper column. To illustrate, a respective metal column can be used to contact a respective printed pad.

[0065] With reference to Fig. Figure 6 shows that the profile of the previously rectangular metallic connection structures 102 has been redefined to a substantially triangular shape. Such a redefinition process allows the profile of the metallic connection structure 102 to be modified according to the requirements of a specific application. For example, the redefinition can be performed by carrying out a reflow process (e.g., reflow soldering) or by diffusion bonding. In the present example, the redefinition results in a local thickening of each of the metallic connection structures 102 selectively in a connection area to the respective component contact 110 of the electronic component 104.Thus, the contact area between a respective metallic connection structure 102 and its associated component contact 110 can be increased by readjustment, thereby improving the reliability of the electrical and mechanical connection between them.

[0066] Like a detail 160 in Fig. Due to the increased temperature (e.g., 230 °C or more) during the reflow process, an intermetallic compound 112 can form in an interface area between the metallic compound structure 102 and the sacrificial carrier 108. This can be caused by a phenomenon such as diffusion and / or migration of material from the sacrificial carrier 108 into the metallic compound structure 102 and vice versa. Advantageously, the intermetallic compound 112 can have a pronounced hardness and can be extremely suitable for establishing an electrical connection with an electronic peripheral.

[0067] As also shown in Detail 160, the elevated temperature can form a dielectric film 114 in an exposed surface region of the metallic compound structures 102 by means of oxidizing the exposed metallic material. Thus, a metal oxide film can be formed on the outer surface of the metallic compound structure 102. Advantageously, the dielectric film 114 can limit the flow of the material of the metallic compound structures 102, which can become flowable during the reflow process.

[0068] In particular, the aforementioned reflow process (for profile setting) can be adjusted to achieve a desired internal pad appearance, for example, smooth or granular. For instance, the reflow process can be performed to adjust the profile of the metallic interconnect structures 102 in order to have a thicker layer of an intermetallic compound 112 between the copper sacrificial carrier 108 and the printed pads representing the metallic interconnect structures 102.

[0069] Back on Fig. 2. Referring to, by setting a corresponding reflow profile and / or by changing materials (for example, by using a sintered material), the structures 102 can also be formed in a granular way.

[0070] With reference to Fig. 7. The electronic component 104, including its component contacts 110 and part of the metallic connection structure 102, can be encapsulated by an encapsulation 106. The encapsulation 106 can be formed by injection molding.

[0071] With reference to Fig. 8. The sacrificial carrier 108 can then be removed from the rest of the preform of the package 100 to expose part of the intermetallic compound 112 of the metallic compound structures 102. Advantageously, the sacrificial carrier 108 can be removed by selective copper etching using the very hard intermetallic compound 112 on the underside of the metallic compound structures 102 at an interface with the sacrificial carrier 108 as a stop layer. Thus, a selective copper etching process stops (or is at least extremely delayed) when the very hard intermetallic compound 112 is reached. This simplifies the process control for removing the sacrificial carrier 108.

[0072] Alternatively, the sacrificial carrier 108 can be removed by mechanical grinding, temperature- or pressure-triggered detachment, or by peeling.

[0073] With reference to Fig. 9 An optional electrically conductive surface finish 116 can be selectively formed on an exposed surface area of ​​the intermetallic compound 112 of the metallic compound structures 102. For example, the surface finish 116 can be formed by a nickel-palladium-gold coating. The surface finish 116 can protect the metallic surfaces, in particular from oxidation.

[0074] With reference to Fig. 10. A structured dielectric protective layer 118 in the form of a solder resist can be formed to expose only defined surface areas of the surface finish 116 on the intermetallic connection 112 of the metallic connection structures 102. This can prevent the formation of unwanted solder bridges. Thus, the final pads of the package 100 can be defined by means of the solder mask. For example, the solder mask can be applied by jet printing.

[0075] After the solder mask is formed, a curing process can be performed. Additionally, array cutting and package singulation can be performed (not shown).

[0076] Fig. Figure 11 shows a cross-sectional view of a package 100 according to yet another exemplary embodiment.

[0077] In the embodiment of Fig. In the embodiment of 11, the surface finish 116 is omitted (although it may be present). Thus, the nickel-palladium-gold coating can be omitted. Fig. 11 have been saved. Furthermore, the package shows 100 according to Fig. 11 a plurality of electrical connection protrusions 120, which are embodied here as solder protrusions, formed on the intermetallic connection 112 of each metallic connection structure 102. In short, it may be possible to add additional solder material to the exposed pads (for example, to have more solder mass for probing purposes).

[0078] Fig. 12 to Fig. Figure 14 shows top views of structures obtained during the fabrication of package 100 according to an exemplary embodiment. This embodiment shows a printed pad grid as a base for chip bonding. The pad grid shown provides a user with a high degree of flexibility with regard to package scalability.

[0079] With reference to Fig. Figure 12 shows a matrix-like structure of metallic interconnect structures 102 (which can be referred to as pads) printed onto a (for example, frame-like) sacrificial support 108. As shown, the pads can be printed with defined grids, size, and pitch.

[0080] With reference to Fig. 13 A plurality of electronic components 104 can be mounted on groups of metallic interconnect structures 102. Thus, the array of pads is simplified according to Fig. 12 a subsequent chip-bonding process and increases its flexibility. In particular, the array of pads according to Fig. 12 suitable to accommodate electronic components 104 of different dimensions, especially different chip sizes. Fig. Figure 13 shows examples of electronic components 104 which are connected to 6, 9 or 12 metallic connection structures 102.

[0081] With reference to Fig. Figure 14 shows different preforms of packages 100 after encapsulation with an encapsulation 106.

[0082] This allows processes such as injection molding, carrier removal, coating, and solder mask printing to be performed simultaneously for the various Package 100 preforms. By using different solder mask stencils, different footprints can be created. Cutting areas of varying sizes result in different package sizes.

[0083] Thus, a common sacrificial carrier 108 with a plurality of metallic connection structures 102 on it can be used to manufacture packages 100 with different properties.

[0084] Fig. Figure 15 shows a cross-sectional view of a package 100 according to an exemplary embodiment.

[0085] Package 100 according to Fig. 15 is of type package 100 according to Fig. 1. Fig. Section 15 shows some advantageous properties and parameters of package 100.

[0086] In areas 140, the solder-lift-like metallic connection structures 102 are connected to column-like (or pad-like) component contacts 110 to achieve good mechanical integrity and a reliable electrical connection. Furthermore, this can avoid any problems with oxidation.

[0087] As also in Fig. As shown in Figure 15, the exposed diameter, D, of a window in the structured dielectric protective layer 118 can be, for example, 200 µm. The maximum vertical extent, B, of a substantially triangular metallic interconnect structure 102 can be, for example, 30 µm. The extent, L, of any metallic interconnect structure 102 extending beyond the window defined in the structured electrical protective layer 118 can be, for example, 100 µm.

[0088] Fig. Figure 16 shows a cross-sectional view of a package 100 according to yet another exemplary embodiment.

[0089] Package 100 according to Fig. 16 has a plurality of electronic components 104, each of which is mounted on an associated plurality of metallic connecting structures 102. According to Fig. 16 is an active area of ​​each of the electronic components 104 facing away from the associated metallic connection structure 102. More precisely, the active area of ​​each electronic component 104 is positioned on its upper main surface. To electrically connect the active areas of the electronic components 104, bond wires 142 (or clips, not shown) can connect the component contacts 110 (pads in the illustrated embodiment) at the active areas to the metallic connection structures 102 without an electronic component mounted thereon.

[0090] The lower main surfaces of the electronic components 104 may or may not have active regions. If active regions are provided on both the lower main surface and the upper main surface of an electronic component 104, a device with a vertical current flow can be encapsulated in the package 100.

[0091] For example, the package can be 100 according to Fig. 16 act as a (for example, stencil-printed) high-voltage driver. Still on Fig. 16. Referring to this, it may be possible to create potential-free pads and to cover pads with a solder mask.

[0092] The embodiment of Fig. 16 differs, for example, from the embodiment of Fig. 1 also in that the component contacts 110 can be embodied as metal pads instead of metal columns.

Claims

[1] A method for producing a package (100), wherein the method comprises: • Applying a metallic interconnect structure (102) comprising a solder or sinter material to a sacrificial support (108); • Mounting an electronic component (104) onto the metallic connecting structure (102); • Encapsulating at least part of the electronic component (104) and the metallic interconnect structure (102) with an encapsulation (106); • then removal of the sacrificial support (108) in order to expose at least part of the metallic connection structure (102); and • Formation of an intermetallic compound (112) in the metallic compound structure (102) at an interface with the sacrificial carrier (108) by means of diffusion or migration of material from the sacrificial carrier (108) into the metallic compound structure (102). [2] The method according to claim 1, wherein the method comprises providing the sacrificial carrier (108) which is temperature stable at least up to 300 °C. [3] The method according to claim 1 or 2, wherein the method comprises providing the sacrificial carrier (108) as one of the group comprising a strip, a plate and a frame. [4] The method according to any one of claims 1 to 3, wherein the method comprises providing the sacrificial carrier (108) which comprises a metal and / or a ceramic. [5] The method according to any one of claims 1 to 4, wherein the method comprises applying the metallic compound structure (102) by means of at least one from the group comprising deposition and printing, in particular screen printing, stencil printing or inkjet printing. [6] The method according to any one of claims 1 to 5, wherein the method comprises mounting the electronic component (104) on the metallic connection structure (102) by means of at least one component contact (110), in particular at least one from the group comprising at least one metal column, at least one metal protrusion, at least one metal sphere and at least one metal pad. [7] The method according to claim 6, wherein the method comprises inserting the at least one component contact (110) into the metallic connection structure (102), in particular with a direct physical contact between at least a part of a side wall of a respective component contact (110) and the metallic connection structure (102). [8] The method according to any one of claims 1 to 7, wherein the method comprises readjusting a profile, in particular a shape, of the metallic connection structure (102) after assembly. [9] The method according to claim 8, wherein the method comprises readjusting the profile of the metallic connection structure (102) by means of at least one from the group comprising a curing process, a reflow process and diffusion bonding. [10] The method according to claim 8 or 9, wherein the method comprises readjusting the profile of the metallic connection structure (102) by locally thickening the metallic connection structure (102) selectively in a connection area to the at least one electronic component (104), in particular selectively in a connection area to at least one component contact (110) of the at least one electronic component (104). [11] The method according to any one of claims 1 to 10, wherein the method comprises forming a dielectric film (114) in an exposed surface area of ​​the metallic compound structure (102) prior to encapsulation. [12] The method according to any one of claims 1 to 11, wherein the method comprises removing the sacrificial carrier (108) by means of at least one of the group comprising selective etching, grinding, peeling and peeling. [13] The method according to any one of claims 1 to 12, wherein the method comprises removing the sacrificial carrier (108) using an intermetallic compound (112) of the metallic compound structure (102) at an interface to the sacrificial carrier (108) as a stop layer. [14] The method according to any one of claims 1 to 13, wherein the method comprises applying a surface finish (116) selectively to an exposed surface area of ​​the metallic compound structure (102) after removal. [15] The method according to any one of claims 1 to 14, wherein the method comprises forming a structured dielectric protective layer (118), in particular a solder resist, to expose at least a defined surface area of ​​the connection structure (102) or a surface finish (116) on the metallic connection structure (102). [16] A package (100) which contains: • a metallic compound structure (102); • an electronic component (104) mounted on the metallic connecting structure (102); and • an encapsulation (106) which encapsulates at least part of the electronic component (104) and the metallic interconnect structure (102); • wherein an exposed part of the metallic compound structure (102) has an intermetallic compound (112). [17] The package (100) according to claim 16, wherein the metallic connection structure (102) is locally thickened in a connection area to the electronic component (104). [18] The package (100) according to claim 16 or 17, wherein the metallic connecting structure (102) is triangular in cross-sectional view. [19] The package (100) according to any one of claims 16 to 18, comprising at least one of the following features: wherein the metallic compound structure (102) comprises or consists of a connected granular material (122); comprising a dielectric film (114) in a surface region of the metallic compound structure (102) which is covered by the encapsulation (106); having an electrical connection protrusion (120), in particular a solder protrusion, which is formed on the intermetallic connection (112); comprising a plurality of electronic components (104), each of which is mounted on at least one associated component of a plurality of metallic connecting structures (102); wherein the electronic component (104) is mounted on a plurality of spatially separated metallic connecting structures (102); wherein an active area of ​​the electronic component (104) faces the metallic connection structure (102) or faces away from the metallic connection structure (102); wherein the metallic connection structure (102) comprises a solder or sintered material; where package (100) is a carrierless package.

Images