An intermediate layer comprising protrusions and filler particles in the recesses between the protrusions

Abstract

A structure (150) includes: a first substructure (152); and a second substructure (154), which is coupled to the first substructure (152) and is a composite material containing filler particles (156) in a matrix (158); wherein a surface of the first substructure (152) has a surface profile including a first protrusion (160) and a first recess (162), and the first recess (162) is configured to enable at least a portion of the filler particles (156) to at least partially enter the first recess (162), thereby forming an intermediate layer (164), wherein the intermediate layer (164) includes the first protrusion (160) of the first substructure (152) and the filler particles (156) in the matrix (158) of the second substructure (154).

Description

Technical Field

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

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

[0003] Delamination of the components of the package can be a problem. Summary of the invention

[0004] It may be necessary to form a material interface with the encapsulant to achieve proper adhesion.

[0005] According to an exemplary embodiment, a structure is provided, comprising: a first substructure; and a second substructure, which is coupled to the first substructure and is a composite material containing filler particles in a matrix; wherein a surface of the first substructure has a surface profile comprising a first protrusion and a first recess, the first recess being configured to enable at least a portion of the filler particles to at least partially enter the first recess, thereby forming an intermediate layer, the intermediate layer comprising the first protrusions of the first substructure and the filler particles in the matrix of the second substructure.

[0006] According to another exemplary embodiment, a package is provided, comprising: at least one functional package body; an encapsulant that encapsulates at least a portion of the at least one functional package body; and a structure having the above-mentioned characteristics that serves as an interface between the encapsulant and at least a portion of the at least one functional package body, wherein a first substructure forms a portion of the at least one functional package body and a second substructure forms at least a portion of the encapsulant.

[0007] According to another exemplary embodiment, a method for manufacturing a structure is provided, wherein the method includes: coupling a first substructure with a second substructure; configuring the second substructure as a composite material comprising filler particles in a matrix; configuring a surface of the first substructure to have a surface profile comprising a first protrusion and a first recess; and at least partially embedding at least a portion of the filler particles in the first recess so as to form an intermediate layer comprising first protrusions of the first substructure and filler particles in the matrix of the second substructure.

[0008] According to an exemplary embodiment, a structure is provided, the structure comprising a first substructure connected to a second substructure, the second substructure having filler particles in a matrix. Traditionally, this arrangement has a mechanical weakness at the interface between the first substructure and the second substructure. According to an exemplary embodiment, by providing a sequence of a first protrusion and a first recess for the first substructure, the size of the first recess is determined so that filler particles can enter the first recess, and improved flexural strength can be obtained in the intermediate layer in the transition region between the first substructure and the second substructure. Therefore, due to the presence of the first protrusion, filler particles and matrix material, an intermediate layer of mixed material properties can be obtained, which unexpectedly shows enhanced flexural strength in the intermediate layer. Therefore, conventional mechanical weaknesses in the interface region between the first substructure and the second substructure can be overcome, and the mechanical integrity of the structure as a whole can be improved. In particular, the intermediate layer significantly promotes adhesion between the first substructure and the second substructure. Crack formation in the intermediate layer can be strongly suppressed.

[0009] Highly advantageously, the structure according to an exemplary embodiment can be implemented as an interface between an encapsulant and a functional package body of a package (e.g., a package for encapsulating an encapsulated electronic component). For example, such a functional package body can be the electronic component, a carrier thereunder and / or another conductive element (e.g., a clip or bonding wire). With the above-described structure in the interface region between the encapsulant and the functional package body, delamination of the components of the package, loss of electrical reliability, deterioration of mechanical integrity, and reduction of package performance can be reliably prevented.

[0010] Description of further exemplary embodiments

[0011] In the following, other exemplary embodiments of the method, structure and package will be described.

[0012] In the context of the present application, the term "package" may particularly denote an electronic device comprising one or more electronic components encapsulated using an encapsulant. Optionally, a carrier and / or one or more conductive contact elements (e.g. bonding wires or clips) for the electronic components may also be implemented in the package.

[0013] In the context of the present application, the term "functional package body" may particularly denote any component or piece of the package that contributes to the function of the package. Such a functional package body may, for example, be a packaged electronic component, such as a semiconductor chip. Another example of a functional package body is a carrier carrying the electronic component, such as a lead frame type carrier. Yet another example of a functional package body is a conductive connection structure, such as a clip or bonding wire for connecting the electronic component to the carrier.

[0014] In the context of the present application, the term "encapsulant" may particularly denote an electrically insulating material surrounding at least a portion of the electronic component and / or at least a portion of the carrier to provide mechanical protection, electrical insulation and optionally to facilitate heat dissipation during operation. In particular, the encapsulant may be a molding compound.

[0015] In the context of the present application, the term "matrix" may particularly refer to a curable liquid or flowable medium and / or slurry. After curing, the matrix may become solid. For example, the matrix may contain a resin, such as an epoxy resin.

[0016] In the context of the present application, the term "filler particles" can particularly refer to (particularly powdered or granular) substances that fill the internal volume in the matrix. By selecting fillers, the physical and / or chemical properties of the encapsulation can be adjusted. Such properties can include thermal expansion coefficient, thermal conductivity, dielectric properties, etc. Therefore, filler particles can be added to fine-tune the physical, chemical, etc. properties of the encapsulation. For example, filler particles can increase the thermal conductivity of the encapsulation so that heat is efficiently removed from the inside of the package (this heat can be generated by electronic components, such as when embodied as power semiconductor chips). Filler particles can also provide improved dielectric decoupling between electronic components and the surrounding environment of the package.

[0017] In one embodiment, a large number of first protrusions and a large number of first recesses may be provided, in particular at least 10, more particularly at least 100, preferably at least 1000 each.

[0018] In one embodiment, the first protrusions and the first recesses define a first roughness.The significant surface roughness between the first substructure and the second substructure may increase the connection surface between the first substructure and the second substructure, and thus may also improve the mechanical strength of the entire structure.

[0019] In one embodiment, the depth of the first protrusion and the first recess is in the range of 0.1 μm to 50 μm, in particular in the range of 0.1 μm to 10 μm, more particularly in the range of 0.6 μm to 5 μm. The depth may represent the vertical distance between the bottom of the first recess and the top of the adjacent first protrusion. Therefore, the first protrusion and the first recess may cooperate to form a microstructure, i.e. a microstructure with a size in the order of micrometers. This may allow filler particles having a size particularly suitable for the molding compound of the semiconductor package to enter the first recess in the intermediate layer to increase the mechanical strength.

[0020] In one embodiment, the diameter of the filler particles (e.g., all or at least 80% or at least 90% of the filler particles) is in the range of 10 nm to 10 μm, particularly in the range of 20 nm to 2 μm, more particularly in the range of 50 nm to 1 μm. Therefore, the size of the filler particles can be adjusted according to the size of the first protrusion and the first recess to enhance the flexural strength of the intermediate layer. In one embodiment, even larger filler particles can be in the molding compound, but for example not in the intermediate layer. Therefore, the filler particles in the molding compound can be even larger, for example up to 100 μm. Therefore, larger filler particles can be present in the resin. However, a mixture of filler particles having less than the above-listed values ​​can be used.

[0021] In one embodiment, the ratio between the vertical depth of the first protrusions (i.e., the vertical distance between the bottom of the first recess and the top of the adjacent first protrusions) and the lateral distance between the peaks of the adjacent first protrusions is at least 0.2, in particular in the range of 0.2 to 5. In other words, the first protrusions can have a significant vertical height and a relatively small horizontal spacing between them. By taking such measures, the protection capability of preventing the destruction and delamination of the intermediate layer under mechanical stress can be significantly improved.

[0022] In one embodiment, the surface of the first substructure has a second protrusion and a second recess formed on the first protrusion and / or the first recess. The second protrusion and the second recess may be provided with a size smaller than the first protrusion and the first recess. Highly advantageously, the first protrusion and the first recess may be modulated by the second protrusion and the second recess, thereby improving the adhesion properties of the intermediate layer. Descriptively, the first protrusion and the first recess may increase the flexural strength at the interface between the first substructure and the second substructure by the introduction of filler. Collaboratively, the second protrusion and the second recess may increase adhesion by promoting mechanical anchoring. In particular, the combination of the first and second recesses and the protrusion may significantly improve the mechanical properties of the entire structure or package.

[0023] In one embodiment, a large number of second protrusions and a large number of second recesses may be provided, in particular at least 10, more particularly at least 100, preferably at least 1000 of each.

[0024] In one embodiment, the second protrusions and the second recesses define a second roughness, which is smaller than the first roughness. Advantageously, the second protrusions and the second recesses also provide additional roughness to the surface of the first substructure, but of smaller size.

[0025] In one embodiment, the depth of the second protrusion and the second recess is in the range of 1 nm to 100 nm, in particular in the range of 10 nm to 50 nm. Therefore, the second protrusion and the second recess cooperate to form a nanostructure, i.e., a nanostructure with a size in the nanometer range. This can promote adhesion between the first substructure and the second substructure to increase the mechanical strength of the structure and the entire package.

[0026] In one embodiment, the second projection and the second recess are configured to enable at least a portion of the matrix to at least partially enter the second recess. However, the second recess may also be configured to prevent filler particles from entering the second recess. Therefore, considering the size restriction, host material rather than filler particles may enter the second recess. The host material in the second recess may improve the adhesion between the first substructure and the second substructure, and may also contribute to mechanical interlocking. Larger filler particles may improve flexural strength when positioned in the first recess.

[0027] In one embodiment, the filler particles have a uniform diameter. In other words, different filler particles can all have substantially the same size. However, alternatively and preferably, the filler particles can have a distributed diameter. When having a distributed diameter rather than a uniform diameter, the filler particles can show even better adhesion between the first substructure and the second substructure.

[0028] In one embodiment, the first portion of the first substructure defining the first protrusion and the second portion of the first substructure defining the second protrusion are made of the same material. By integrally forming the first protrusion and the second protrusion from a common body of the same material, the mechanical integrity of the structure as a whole can be improved.

[0029] In another embodiment, the first part of the first substructure defining the first protrusion and the second part of the first substructure defining the second protrusion are made of different materials. By taking this measure, the properties of the first protrusion and the properties of the second protrusion can be adjusted separately to fine-tune the desired properties to improve adhesion.

[0030] In one embodiment, the first substructure comprises a substrate on which the first protrusions are formed. Such a substrate or support may be subjected to a special treatment, such as electroplating, to form a sequence of first protrusions and first recesses thereon.

[0031] In one embodiment, the base and the first protrusion are made of the same material, which can enhance the stability of the entire structure.

[0032] In another embodiment, the substrate and the first protrusion are made of different materials. This can allow the substrate material and the material of the first protrusion to be adjusted separately. For example, the first protrusion can be deposited on the substrate.

[0033] In one embodiment, the base and the first protrusion are in direct physical contact with each other. This may facilitate proper adhesion or cohesion.

[0034] In one embodiment, the structure includes an intermediate layer, in particular a seed layer, between the substrate and the first protrusion. Sandwiching the seed layer between the substrate and the protrusion can simplify the formation of the first protrusion and can also promote adhesion. Moreover, such a seed layer can also be used as a corrosion barrier. Therefore, the seed layer can be a corrosion barrier or a diffusion barrier. It can be formed of the same material as the first protrusion or a different material.

[0035] In a preferred embodiment, at least one undercut is formed between the substrate and the first projection. In the context of the present application, the term "undercut" may particularly denote a hollow space defined by the substrate and the first projection, such that in the undercut region, the angle between the side wall of the corresponding first projection and the substrate is less than 90°, i.e., an acute angle. The undercut may be a cutout formed in the lower portion of the corresponding first projection to produce an overhang. The undercut may define a concave surface that is inaccessible using a straight element. It has been shown that the formation of the undercut significantly improves the flexural strength of the intermediate layer, particularly when filler particles are also present in one or more undercuts.

[0036] In one embodiment, the at least one undercut is formed to promote mechanical interlocking and thereby promote adhesion within the intermediate layer. This can further improve the mechanical strength of the structure and the package. For example, the at least one undercut corresponds to a hole geometry having a side angle of less than 90°.

[0037] In one embodiment, the filler particles have a selected coefficient of thermal expansion (CTE) value such that the presence of the filler particles in the intermediate layer reduces the mismatch in the coefficient of thermal expansion between the first substructure and the second substructure compared to the absence of the filler particles in the intermediate layer. In other words, the CTE mismatch between the first structure and the matrix material can be reduced in the intermediate layer. Therefore, thermal stress caused by the different thermal expansion of the first protrusion and the matrix material when the temperature changes can be reduced.

[0038] In one embodiment, the thickness of the intermediate layer is in the range of 0.1 μm to 10 μm, in particular in the range of 0.6 μm to 5 μm. With these dimensions, an increased flexural strength can be achieved well.

[0039] In one embodiment, the first substructure comprises or consists of copper. However, the first substructure may also be made of other metals, such as aluminum. The interface between the metal and the encapsulant may be a mechanical weak point in conventional packages.

[0040] In one embodiment, the second substructure is a molding compound. The molding compound may include a matrix of flowable and hardenable material and filler particles embedded therein. For example, the filler particles may be used to adjust the properties of the molded part. In particular, the adjustment may be performed to enhance thermal conductivity, adapt the coefficient of thermal expansion (CTE) and / or increase flexural strength.

[0041] In one embodiment, the structure includes additional adhesion promoting materials between the second protrusion, the second recess and the second substructure. For example, such additional adhesion promoting materials may include fibers, films and / or nanoparticles. From the description, a triple adhesion promoting structure, i.e., a coarser roughness (provided by the first protrusion and the first recess) and a finer roughness (provided by the second protrusion and the second recess) and additional adhesion promoters thereon, can be provided. This can further improve the mechanical strength of the intermediate layer.

[0042] In one embodiment, at least a portion of the first protrusion tapers toward the second substructure. This can form a sufficiently large opening, thereby simplifying the entry of filler particles into the first recess.

[0043] In one embodiment, the first protrusions and / or the second protrusions are arranged in a two-dimensional random manner. In other words, the first protrusions and / or the second protrusions can be arranged in a random manner over a continuous surface area. It turns out that this continuous adhesion-promoting blanket structure with an irregular pattern of protrusions and recesses is a particularly powerful profile for improving adhesion and enhancing flexural strength.

[0044] In one embodiment, the at least one functional package body includes a carrier. In the context of the present application, the term "carrier" can particularly represent a support structure (which can be at least partially conductive), which is used as a mechanical support structure for the electronic components to be mounted thereon, and can also contribute to the electrical interconnection between the electronic components and the periphery of the package. In other words, the carrier can realize mechanical support functions and electrical connection functions. The carrier can include or be composed of a single component, a plurality of components or a subassembly of the carrier engaged via encapsulation or other package components. When the carrier forms a part for a lead frame, it can be or can include a bare die pad.

[0045] In one embodiment, the at least one functional package body includes electronic components. In the context of the present application, the term "electronic components" may particularly include semiconductor chips (particularly power semiconductor chips), active electronic devices (e.g. transistors), passive electronic devices (e.g. capacitors or inductors or ohmic resistors), sensors (e.g. microphones, light sensors or gas sensors), actuators (e.g. loudspeakers) and micro-electromechanical systems (MEMS). However, in other embodiments, the encapsulated devices may also be of different types, such as electromechanical components, particularly mechanical switches, etc.

[0046] The electronic components can be mounted on a carrier, so that the carrier can fulfill a mechanical support function as well as an electrical coupling function.

[0047] In one embodiment, the at least one functional package body includes a conductive contact element that electrically couples the electronic component to the carrier. Such a conductive contact element can be a clip, a bonding wire or a bonding tape. The clip can be a curved conductor that realizes electrical connection to the upper main surface of the corresponding electronic component with a high connection area. As a supplement or replacement of this clip, one or more other conductive interconnects can also be implemented in the package, for example, bonding wires and / or bonding tapes that connect the electronic component to the carrier or connect different pads of the electronic component.

[0048] In one embodiment, the first protrusion and the second protrusion are formed by electroplating. The term "electroplating" can represent the process of using electric current to reduce dissolved metal cations so that they form a thin bonding metal coating on the electrode. The term electroplating can also represent the electro-oxidation of anions on a solid substrate. Electroplating can be used to change the surface properties of the substrate to promote adhesion. By adjusting the electroplating parameters in the electric reactor, the characteristics of the first protrusion and the first recess (and optionally also the second protrusion and the second recess) can be adjusted. For example, it can be used to adjust the electrolyte composition of the protrusion and recess characteristic parameters that are appropriately selected during electroplating, the current density, temperature, plating time (for example, in the range of 3 seconds to 7 seconds, for example 5 seconds) etc. It can be applied to pulse plating. By making such adjustments, needle-shaped and / or sponge-shaped protrusions and recess arrays can be obtained. This can allow the formation of the above-mentioned microstructure and nanostructure. Laser roughening can also be performed to form (particularly the second) microstructure.

[0049] In one embodiment, the method comprises forming the first protrusion and the second protrusion in a common process, in particular simultaneously. By forming the first and second protrusions and the first and second recesses simultaneously, simple manufacturing is possible. For example, this can be done by electroplating.

[0050] In one embodiment, an adhesion promoter may be provided in the intermediate layer, preferably in at least two dimensions (particularly by the first protrusion and recess and the second protrusion and recess). A larger-sized adhesion promoter may be provided in the form of a first protrusion and a first recess, while a smaller-sized adhesion promoter may be provided in the form of a second protrusion and a second recess. In the context of the present application, the term "adhesion promoter" may particularly represent any material and / or measure that enhances the adhesion between the first substructure and the second substructure. More specifically, this adhesion promoter (or coupling agent or bonding agent) may serve as an interface between the first substructure and the second substructure to enhance the adhesion between the two substructures.

[0051] In particular, a morphological adhesion promoter, i.e., an adhesion promoter with a morphological structure, can be provided. Accordingly, the manufacturing method can include forming an adhesion promoter, particularly a morphological adhesion promoter, on the corresponding functional encapsulation body before encapsulation. In the context of the present application, the term "morphological structure" can particularly refer to a structure having a topological structure and / or a porous structure and / or shaped in a manner to increase the connection surface of the connection material with the encapsulation and / or the functional encapsulation body so as to promote adhesion. In addition, the morphology of the morphological adhesion promoter can cause a favorable mechanical interlock between the material of the encapsulation and / or the functional encapsulation body and the material of the morphological adhesion promoter. In other words, the morphological structure promotes adhesion due to its shape, rather than promoting adhesion only due to its chemical properties. However, the morphological structure can also be made synergistically by a material that promotes adhesion in view of the inherent characteristics attached to the shape. In particular, the morphological adhesion promoter can be a porous material. The specific shaping of the inner surface of the adhesion promoter, particularly the increase of the inner surface, can enhance the adhesion between the first substructure and the second substructure (e.g., encapsulation and chip) facilitated by the morphological adhesion promoter.

[0052] In one embodiment, the morphological adhesion promoter includes at least one of the group consisting of metal structures, alloy structures, chromium structures, vanadium structures, molybdenum structures, zinc structures, manganese structures, cobalt structures, nickel structures, copper structures, flame-deposited structures, roughened metal structures (especially roughened copper structures or roughened aluminum oxide structures), and any oxides, nitrides, carbides, and selenides of any of the above structures. All structures may contain or consist of these metals and / or their alloys. In addition, these structures may contain or consist of these metal and alloy oxides thereof. In particular, in different embodiments, single oxides and mixed oxides are possible. Whether the alloy is oxidized may depend on the thermal budget in production. However, other materials and structures may also be used for morphological adhesion promoters. The flame-deposited structures mentioned above may contain silicon dioxide, any titanium oxide (e.g., TiO2, TiO ... x O y Any organometallic precursor that can be mixed with a combustion gas, such as propane or butane, and combust to form a specific metal oxide can be used.

[0053] In particular, the morphological adhesion promoter may be formed using atomic layer deposition (ALD), chemical vapor deposition (CVD), or the like.

[0054] In another embodiment, the adhesion promoter is an organic adhesion promoter, such as silane. Such an organic adhesion promoter can promote adhesion due to its chemical properties.

[0055] In one embodiment, the first and / or second recesses include at least one of the group consisting of holes, dendrites, and gaps between islands of the patterned structure. However, other kinds of openings may be formed as long as they increase the surface of the morphological adhesion promoter and promote mechanical interlocking.

[0056] In one embodiment, filler particles are selected from the group consisting of crystalline silica, fused silica, spherical silica, titanium oxide, aluminum hydroxide, magnesium hydroxide, zirconium dioxide, calcium carbonate, calcium silicate, talc, clay, carbon fiber, glass fiber and mixtures thereof. However, other filling materials are also possible according to the requirements of specific applications. For example, filler particles (such as SiO2, Al2O3, Si3N4, BN, AlN, diamond, etc.) for improving thermal conductivity can be embedded in the encapsulation. However, in addition to or instead of the mentioned filler particles, other filler particles can also be implemented in the encapsulation. In particular, organic particles can be used as fillers (for example, fillers can also include polymers or polymer mixtures or be composed of them, such as: epoxy resins, polyethylene, polypropylene, etc.). In addition, it should be mentioned that the filler can be treated in a manner to improve the adhesion between the filler and the encapsulation comprising the filler. The filler coating can be selected from the group of silane, thiol or porous structure. Similarly, porous fillers can be used. In particular, filler particles can be provided in the form of nanoparticles or microparticles. The filler particles can have the same size or can be provided with a certain distribution of particle sizes. Such a distribution of particle sizes may be preferred because it can improve the filling of the gaps in the interior of the encapsulate. For example, the shape of the filler particles can be random, spherical, cuboid, flaky and film-like. The filler particles can be modified, coated and / or treated to improve adhesion and / or chemical bonding with the surrounding matrix. An example is silane. The coating can also change the surface energy of the filler, thereby improving and achieving the wetting of the solution / matrix.

[0057] In one embodiment, the package includes a carrier on which the electronic components are mounted. For example, such a carrier may be a lead frame (e.g., made of copper), a DAB (direct aluminum bonding), a DCB (direct copper bonding) substrate, etc. In addition, at least a portion of the carrier together with the electronic components may be encapsulated by an encapsulant.

[0058] Preferably, before the encapsulant is at least partially encapsulated, the surface of the electronic component (preferably, the entire metal surface of the electronic component) may at least partially have protrusions and recesses as described herein. Also preferably, before the encapsulant is at least partially encapsulated, the surface of the carrier (preferably, the entire metal surface of the carrier) may at least partially be provided with protrusions and recesses as described herein. This can further improve the mechanical reliability of the package.

[0059] In one embodiment, the package includes a conductive contact element that electrically couples the electronic component to the carrier. Preferably, before the encapsulated object is at least partially encapsulated, the surface of the conductive contact element (preferably, the entire metal surface of the conductive contact element) may be at least partially provided with protrusions and recesses as described herein. For example, the conductive contact element may include a clip, a wire bonding structure and / or a strip bonding structure. The clip may be a three-dimensionally curved plate-type connecting element having two planar sections to be connected to the upper main surface of the corresponding electronic component and the upper main surface of the chip carrier, wherein the two planar sections are interconnected by an inclined connecting section. As an alternative to such a clip, a wire bonding structure or a strip bonding structure may also be used, which is a flexible conductive wire or a strip-shaped body, one end of which is connected to the upper main surface of the corresponding chip and the other opposite end is electrically connected to the chip carrier.

[0060] In one embodiment, the method comprises pre-treating at least a portion of the electronic component, the carrier and / or the conductive contact element to promote adhesion between the encapsulant and at least a portion of the electronic component, the carrier and / or the conductive contact element. Thus, the adhesion between the above-mentioned encapsulant and the functional package body can be improved by applying an additional device-level treatment that promotes adhesion. Highly advantageously, the encapsulant or a portion thereof (e.g., a metal surface thereof) can be pre-treated to improve its adhesion to the above-mentioned encapsulant. For example, the surface of the encapsulant or a portion thereof to be encapsulated by the encapsulant can be surface activated. Such surface activation can be achieved, for example, by plasma treatment of the corresponding surface, in particular the corresponding metal surface.

[0061] In one embodiment, the package is configured as one of the group consisting of a power module connected by a lead frame, 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. The package of the sensor and / or electromechanical device is also a possible embodiment. In addition, the exemplary embodiment may also be related to a package used as a nanobattery or a nanofuel cell or other devices with chemical, mechanical, optical and / or magnetic actuators. Therefore, the package according to an exemplary embodiment is fully compatible with the standard packaging concept (especially fully compatible with the standard TO packaging concept), and is presented as a conventional package in appearance, which is very convenient for users to use.

[0062] In one embodiment, the package is configured as a power module, such as a molded power module. For example, one exemplary embodiment of the package may be an intelligent power module (IPM). Another exemplary embodiment of the package is a dual in-line package (DIP).

[0063] In one embodiment, the electronic component is 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 other type of transistor (e.g., MOSFET, JFET, etc.) and / or at least one integrated diode. Such integrated circuit elements can, for example, be made with silicon technology or based on wide bandgap semiconductors (such as silicon carbide). The semiconductor power chip may include one or more field effect transistors, diodes, inverter circuits, half bridges, full bridges, drivers, logic circuits, other devices, etc.

[0064] In one embodiment, the electronic component is subjected to vertical current flow. The package structure according to the exemplary embodiment is particularly suitable for high power applications requiring vertical current flow, i.e., current flow in a direction perpendicular to two opposite major surfaces of the electronic component, wherein one major surface is used to mount the electronic component on a carrier.

[0065] As a substrate or wafer forming the basis of the 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 with GaN or SiC technology.

[0066] In addition, exemplary embodiments can utilize standard semiconductor processing techniques, such as appropriate etching techniques (including isotropic and anisotropic etching techniques, in particular plasma etching, dry etching, wet etching), patterning techniques (which may involve photolithography masks), deposition techniques (such as chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), sputtering, etc.).

[0067] 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

[0068] The accompanying drawings illustrate exemplary embodiments and are included to provide a further understanding of exemplary embodiments and constitute a part of this specification.

[0069] In the attached picture:

[0070] Figure 1A A structure according to an exemplary embodiment is shown.

[0071] Figure 1B A package according to an exemplary embodiment is shown.

[0072] Figure 2 A flow chart of a method according to an exemplary embodiment is shown.

[0073] Figure 3 A cross-sectional view of a package to be mounted on a mounting structure is shown according to an exemplary embodiment.

[0074] Figure 4 An intermediate layer of a structure for a package according to an exemplary embodiment is shown.

[0075] Figure 5 An intermediate layer of a structure for a package according to another exemplary embodiment is shown.

[0076] Figures 6 to 9 is an image of a structure of a package according to an exemplary embodiment.

[0077] Fig.10 An undercut portion of a first protrusion of a structure for a package according to an exemplary embodiment is shown.

[0078] Fig.11 The relationship between the vertical depth of a first protrusion and the distance between adjacent first protrusions of a structure for a package according to an exemplary embodiment is shown.

[0079] Fig.12 The relationship between the vertical depth of a first protrusion derived from an image of a structure of a package and the distance between adjacent first protrusions according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0080] The illustrations in the figures are schematic and not drawn to scale.

[0081] Before the exemplary embodiments will be described in more detail with reference to the accompanying drawings, some general considerations will be summarized based on the context of the exemplary embodiments that have been developed.

[0082] In many applications, adhesion between different materials is critical for device safety. In the semiconductor industry, adhesion between mold compounds and other package components is especially critical.

[0083] Recent research by the inventors shows that, despite conventional solutions that aim to significantly improve adhesion by mechanical anchoring, there is still a weak point at the interface between the molding compound and other package materials such as the lead frame (or in fact slightly above the interface). The weak point is located at the first layer of the molding compound. Without wishing to be bound by a particular theory, it is currently believed that the weak point is caused by a reduction in flexural strength in the region, which is due to the fact that there is no filler directly at the interface. Therefore, there is actually a layer of pure resin just above the adhesion-promoting layer on the substrate. Compared with the bulk properties of the molding material, the layer has a very low flexural strength. This weak point is where delamination occurs, which may actually be a cohesive failure rather than an adhesive failure. Since the flexural strength of the molding compound may be greatly reduced at higher temperatures, the risk of cohesive failure occurring above the interface may be greatly increased. Therefore, improving the flexural strength at the interface may greatly improve the reliability of the device, especially at higher temperatures.

[0084] Morphological adhesion promoters can be used for good adhesion. Mechanical anchoring can improve adhesion. However, this does not improve the flexural strength of the interface. Therefore, especially at higher temperatures, there is a risk of cohesive failure in the unfilled areas in the first layer of the molding compound.

[0085] The inventors surprisingly found that, although conventional adhesion promoters can increase adhesion to the molding compound by mechanical interlocking, the adhesion and mechanical interlocking between the morphological adhesion promoter layer and the molding compound are so good that the delamination mechanism (e.g., during shear testing) is converted from an adhesive mode to a cohesive mode. Therefore, in the filler-free areas of the molding residues in the morphological adhesion promoter layer, the molding may be destroyed. This has been demonstrated by TOF SIMS (time of flight-secondary ion mass spectrometry) analysis.

[0086] Additionally, it has been found that the unfilled layer between the functional package body and the molding compound has very high coefficient of thermal expansion (CTE) values, which may lead to high stresses if the temperature varies.

[0087] The inventors have also discovered that since the weakest point is not the interface itself, but the flexural strength in the molded material near the interface, the material system can be further improved by improving the interface flexural strength. However, the flexural strength of the molded material near the interface may be lower because there is no filler directly at the interface (similar to the reduced flexural strength in unfilled epoxy).

[0088] According to exemplary embodiments, it may be advantageous to combine mechanical anchoring from morphological adhesion promoters with a roughened surface. For example, it may be advantageous to plate a mixture of micro and macro protrusions as a dual adhesion promoter. This may improve the flexural strength of the interface because the filler particles of the encapsulant may be partially incorporated into an intermediate layer that may be formed from the porous adhesion promoter and the matrix or resin of the molding compound.

[0089] In conventional methods, the unfilled area of ​​the mold compound interface described above may constitute a weak point because the CTE of pure epoxy is much higher than the CTE of the bulk mold compound and also much higher than the CTE of the copper layer. This CTE mismatch may cause thermomechanical stress.

[0090] Exemplary embodiments may also reduce this CTE mismatch because fillers to be incorporated into the intermediate layer may lower the CTE value of the molding compound, thereby reducing thermomechanical stress.

[0091] In particular, example embodiments may improve the connection between the mold compound and other package materials (also referred to as the functional package body) by improving the flexural strength at the interface.

[0092] For example, it has been found that at room temperature, the adhesion of the molding material can be increased by about 30%. At higher temperatures, the effect is expected to be even greater due to the reduction in the flexural strength of the resin at higher temperatures. There is also available data showing the correlation between shear force at key material interfaces and temperature-dependent flexural strength at high shear temperatures. In particular, data are available for several molding compounds including TOF-SIMS measurements that show that cohesive failure occurs in the less-filled molding compound layer above the morphological adhesion layer (polymer is still present in the morphological adhesion layer after shearing).

[0093] In view of the foregoing, an exemplary embodiment provides an intermediate layer with improved flexural strength at the interface between the first substructure and the second substructure. More specifically, an exemplary embodiment provides a first substructure (e.g., a first material) in contact with a second substructure (e.g., a second material), wherein the second material is a composite material consisting of fillers of different sizes and a matrix system that holds the fillers together. The first substructure can be provided with a specific roughness that allows at least a portion of the filler particles to enter at least a portion of the rough layer during the application of the second substructure to the first substructure. By taking the measures, an intermediate layer can be formed at the interface between the first substructure and the second substructure. The intermediate layer can be composed of the first substructure, the matrix of the second substructure, and the filler particles of the second substructure.

[0094] Alternatively and preferably, the first substructure may have nanostructures which can be infiltrated by the matrix system of the second substructure when the second substructure is applied onto the first substructure (eg, a base structure with morphological adhesion promoters).

[0095] Optionally and preferably, the intermediate layer may be provided with an additional sealing layer below the nanostructured layer (eg a seed layer of morphological adhesion promoters).Such an additional layer may also be realized by very fine filler particles.

[0096] Regarding the size or pore size of the recess, for example, a first protrusion and a first recess having a size or pore size in the range of 0.1 μm to 10 μm, for example, 1 μm, can be provided. Accordingly, for example, a second protrusion and a second recess having a size or pore size in the range of 1 nm to 100 nm, for example, 30 nm, can be provided.

[0097] In particular, the combination of macroporosity (provided by the first protrusions and the first recesses) and microporosity (provided by the second protrusions and the second recesses) may be highly advantageous for the following reasons: Microporosity may increase adhesion by mechanical anchoring, but flexural strength may be limited when microporosity is provided without macroporosity. Macroporosity may increase flexural strength at the interface by incorporating fillers. However, adhesion may be limited when macroporosity is provided without microporosity. By combining microporosity and macroporosity, a highly advantageous synergistic bond may be obtained.

[0098] Advantageously, the fibers may be applied to the surface after treatment with the morphological adhesion promoter to improve flexural strength during encapsulation, in particular during molding.

[0099] In another advantageous embodiment, a thin film of an active ingredient (e.g., an epoxy crosslinker) can be applied on top of the morphological adhesion layer by impregnation prior to the molding process, which can result in a stronger linkage of the epoxy resin near the interface. Thus, taking such measures can further increase the flexural strength near the morphological adhesion promoter layer, while the flexural strength in the molding compound can remain unchanged.

[0100] In yet another embodiment, the morphological adhesion promoter layer (i.e., the first substructure comprising first protrusions and first recesses and optionally second protrusions and second recesses) can be immersed in a pool containing nanoparticles so that the nanoparticles can attach to the morphological adhesion layer before encapsulation, in particular molding.

[0101] Advantageously, the first substructure according to an exemplary embodiment is characterized by a non-directional but uniform roughness.

[0102] In one embodiment, the first substructure with the porous layer can be implemented as a ZnV morphological adhesion promoter. In one embodiment, the first substructure can be processed by copper etching at the grain boundaries. In a further embodiment, the first substructure can be processed by laser surface structuring.

[0103] Figure 1A A structure 150 is shown according to one exemplary embodiment.

[0104] Figure 1A The cross-sectional view of FIG. 1 shows a structure 150, which includes a first substructure 152 and a second substructure 154 in contact with the first substructure 152. The second substructure 154 is a composite material including filler particles 156 in a matrix 158. The surface of the first substructure 152 has a surface profile including first protrusions 160 and first recesses 162, each first recess 162 being arranged between two adjacent first protrusions 160 and configured to allow the filler particles 156 to enter the first recesses 162. Thus, an intermediate layer 164 is formed, which includes the first protrusions 160 of the first substructure 152 and the filler particles 156 in the matrix 158 of the second substructure 154.

[0105] Figure 1B A package 100 according to an exemplary embodiment is shown.

[0106] Figure 1B The cross-sectional view of the package 100 shown in FIG. 1 shows a functional package body 102 , 104 in the form of a carrier 102 and an electronic component 104 mounted on the carrier 102 . An encapsulant 106 encapsulates the functional package body 102 , 104 .

[0107] As shown in the partial enlargement 111, a structure 150 (such as Figure 1A ) as the interface between the encapsulant 106 and the corresponding functional package body 102, 104 ( Figure 1B This is only shown for the carrier 102 .) The first part structure 152 forms part of the respective functional encapsulation body 102 , 104 . The second part structure 154 corresponds to the encapsulation 106 .

[0108] Figure 2 A flow chart 200 is shown of a method of manufacturing a structure 150 according to an exemplary embodiment.

[0109] As shown in block 202, the method includes contacting the first substructure 152 with the second substructure 154. Corresponding to block 204, the method also includes configuring the second substructure 154 as a composite material including filler particles 156 in a matrix 158. As shown in block 206, the method includes configuring the surface of the first substructure 152 to have a surface profile including first protrusions 160 and first recesses 162. In addition, the method includes at least partially embedding at least a portion of the filler particles 156 in the first recesses 162 to form an intermediate layer 164, the intermediate layer 164 including the first protrusions 160 of the first substructure 152 and the filler particles 156 in the matrix 158 of the second substructure 154 (see block 208).

[0110] Figure 3 A cross-sectional view of a package 100 implemented as a transistor outline (TO) package according to an exemplary embodiment is shown. The package 100 is mounted on a mounting structure 132, which is implemented here as a printed circuit board.

[0111] The mounting structure 132 includes electrical contacts 134 implemented as plating in through holes of the mounting structure 132. When the package 100 is mounted on the mounting structure 132, the electronic components 104 of the package 100 are electrically connected to the electrical contacts 134 via the conductive base 102 of the package 100 (here implemented as a lead frame made of copper).

[0112] The package 100 therefore comprises an electrically conductive carrier 102 , an electronic component 104 (embodied here as a power semiconductor chip) adhesively mounted (see reference numeral 136 ) on the carrier 102 , and an encapsulation 106 encapsulating a part of the carrier 102 and the electronic component 104 .

[0113] As shown in detail enlargements 113, 115, and 117, encapsulant 106 is a molding compound that includes a matrix (epoxy) 158 and filler particles 156 (eg, made of aluminum oxide) in matrix 158. Filler particles 156 have a diameter D.

[0114] from Figure 3 It can be seen that pads on the upper main surface of the electronic component 104 are electrically coupled to the carrier 102 via bonding wires as electrically conductive contact elements 110 .

[0115] During operation of the power package 100, the power semiconductor chip in the form of the electronic component 104 generates a considerable amount of heat. At the same time, it should be ensured that any undesired current flow between the bottom surface of the package 100 and the environment is reliably avoided.

[0116] In order to ensure electrical insulation of the electronic component 104 and to dissipate heat from the interior of the electronic component 104 to the environment, an electrically insulating and thermally conductive interface structure 108 may be provided at the bottom of the package 100, covering the exposed surface portion of the carrier 102 and the connection surface portion of the encapsulant 106. The electrically insulating properties of the interface structure 108 may prevent undesired current flow even if there is a high voltage between the interior and the exterior of the package 100. The thermally conductive properties of the interface structure 108 may facilitate heat dissipation from the electronic component 104 via the conductive carrier 102 (made of thermally conductive copper), through the interface structure 108, and toward the heat sink 112. The heat sink 112, which may be made of a highly thermally conductive material such as copper or aluminum, has a base 114 directly connected to the interface structure 108, and has a plurality of heat sinks 116 extending parallel to each other from the base 114 to dissipate heat to the environment.

[0117] Referring again to the local enlargement 117, corresponding to Figure 1A The structure 150 is provided as an interface between the encapsulant 106 (corresponding to the second substructure 154) and the metal surface of the electronic component 104 as the functional package body (corresponding to the first substructure 152). Figure 1A The structure 150 is also provided as an interface between the encapsulant 106 (corresponding to the second substructure 154) and the metal surface of the carrier 102 (corresponding to the first substructure 152) as another functional package body. Figure 1A The structure 150 is also provided as an interface between the encapsulant 106 (corresponding to the second substructure 154) and the metal surface (on each of the two opposite surfaces shown, corresponding to the first substructure 152) of the conductive contact element 110 as another functional package body. Preferably, all metal surfaces of the functional package bodies 102, 104, 110 can be configured as the first substructure 152 for forming the following Figure 1A and below (see Figure 4 and Figure 5 ) The intermediate layer 164 described in more detail in ). By taking the measures described, the flexural strength of the package 100 can be increased and thus its mechanical stability can be improved, and the tendency of delamination within the package 100 can be suppressed.

[0118] Figure 4 An intermediate layer 164 of the structure 150 for the package 100 is shown according to an exemplary embodiment.

[0119] As shown, the structure 150 includes a first substructure 152 and a second substructure 154 in contact with the first substructure 152 .

[0120] The first substructure 152 includes a base 176 on which a first protrusion 160 is formed. Figure 4 , the first protrusion 160 tapers toward the second substructure 154. The base body 176 and the first protrusion 160 may be made of the same material, such as copper. Figure 4 , the substrate 176 and the first protrusion 160 are in direct physical contact with each other. More specifically, the substrate 176 and the first protrusion 160 can be formed integrally. The surface of the first substructure 152 has a second protrusion 168 and a second recess 170 formed on the first protrusion 160 and the first recess 162. For example, the sequence of the second protrusion 168 can be formed by a porous ZnV layer (or ZnMo layer). Therefore, the first part 172 of the first substructure 152 defining the first protrusion 160 and the second part 174 of the first substructure 152 defining the second protrusion 168 are made of different materials.

[0121] The second substructure 154 is implemented as a composite material including filler particles 156 (eg, made of an inorganic material such as metal oxide spheres) in a matrix 158 (eg, epoxy resin).

[0122] As shown, the surface of the first substructure 152 has a surface profile or topology including first protrusions 160 and first recesses 162, which are configured to allow some filler particles 156 to partially or fully enter the first recesses 162, thereby forming an intermediate layer 164. The intermediate layer includes the first protrusions 160 of the first substructure 152 and the filler particles 156 in the matrix 158 of the second substructure 154.

[0123] As shown, the first protrusion 160 and the first recess 162 define a rough first roughness. For example, the first protrusion 160 and the first recess 162 have a depth Rz of about 1 μm. The vertical thickness of the intermediate layer 164 corresponds to the vertical thickness Rz of the first protrusion 160, and therefore can also be, for example, 1 μm. The filler particles 156 may have a distribution characteristic of different diameters D in the range of 50 nm to 1 μm, wherein at least a portion of the filler particles 156 has a larger size. In other words, the filler particles 156 have an uneven diameter distribution. Considering this size characteristic of the filler particles 156, they can be located in the intermediate layer 164. For example, the filler particles 156 can account for at least 1% of the volume of the intermediate layer 164, in particular at least 5% of the volume, and more particularly at least 10% of the volume. The distance L between adjacent peaks 166 of the first protrusion 160 can be, for example, 2 μm. Therefore, the ratio between the depth Rz and the distance L can be 0.5. This relatively large value ensures that the material of the intermediate layer 164 is a suitable and highly heterogeneous mixture of the materials of the matrix 158 , the filler particles 156 , and the first protrusions 152 .

[0124] from Figure 4 It can also be seen that the second protrusions 168 and the second recesses 170 define a finer second roughness that is less than the coarser first roughness. Descriptively, the second protrusions 168 are modulated on the corresponding first protrusions 152. The second protrusions 168 and the second recesses 170 have nanoporous properties, thereby increasing the contact surface between the first substructure 152 and the second substructure 154, which can further enhance adhesion. For example, the second protrusions 168 and the second recesses 170 have a depth B of about 30 nm. Given their smaller size, the second protrusions 168 and the second recesses 170 are configured to enable the material of the matrix 158 to enter the second recesses 170, while larger filler particles 156 may not be able to enter the second recesses 170. Descriptively, the second protrusions 168 increase the contact surface with the material of the matrix 158, thereby acting as porous morphology adhesion promoters.

[0125] Advantageously, filler particles 156 can be provided with a value for a coefficient of thermal expansion selected as a result of material selection, such that the presence of filler particles 156 in intermediate layer 164 reduces the mismatch between the coefficients of thermal expansion between the material of the first substructure 152 and the material of the second substructure 154, compared to a situation in which no filler particles 156 are present in intermediate layer 164, i.e. a situation in which the first recess 162 is completely filled with material of the matrix 158.

[0126] Optionally and as shown in detail enlargement 119, structure 150 may include additional adhesion promoting material 180 between second protrusion 168, second recess 170 and second substructure 154. Such additional adhesion promoting material 180 is implemented as an adhesion promoting film, for example.

[0127] By following Figure 4 Configuration, can make the interface between first substructure 152 and second substructure 154 have improved flexural strength by forming intermediate layer 164. The interface with improved flexural strength can be obtained by intermediate layer 164 that relies on the combination of microscopic and macroscopic adhesion promoting structures in the form of larger first protrusion 160 and smaller second protrusion 168, wherein each group of second protrusions 168 is formed on a first protrusion 160 or on a first recess 162. Therefore, an improved interface region adjacent to the copper surface can be obtained. Morphological adhesion promoter can be formed as second protrusion 168 (e.g., by electroplating or by atomic layer deposition, ALD). Then, first substructure 152 can be connected to second substructure 154 in a firmly adhered manner, and second substructure 154 includes matrix 158 (e.g., implemented as (e.g., polymer) resin) and filler particles 156.

[0128] Advantageously, the intermediate layer 164 has a lower CTE value than the pure epoxy material according to the matrix 158. By making it possible for the filler particles 156 to enter the first recesses 162, CTE compensation occurs, which results in lower stresses.

[0129] As Figure 4 As an alternative to the embodiment shown in FIG. 1 , the hole in the form of the first recess 162 may have a side wall angle of less than 90° (rather than Figure 4 The side wall angle is less than 90°. Fig.10 , and may result in the formation of an undercut 151 which further promotes adhesion.

[0130] Figure 4 Reference numeral 121 in the figure schematically shows a possible crack path, along which cracks in the structure 150 may occur if an excessive mechanical load (e.g., shear force) is applied to the structure 150. As shown in the figure, by ensuring that a large number of filler particles 156 are located in the first recess 162, the crack path 121 is greatly extended and complicated. From the description, the possibility of cracks or cracks in the intermediate layer 164 can be reduced, and the mechanical stability of the structure 150 as a whole can be improved.

[0131] Figure 5 An intermediate layer 164 for the structure 150 of the package 100 is shown according to another exemplary embodiment.

[0132] Figure 5 Examples and Figure 4 The embodiment of the invention is different in that, according to Figure 5 , the first portion 172 of the first substructure 152 defining the first protrusion 160 and the second portion 174 of the first substructure 152 defining the second protrusion 168 are made of the same material and can be formed integrally. This configuration makes it possible to preferably form the first protrusion 160 and the second protrusion 168 in a common simultaneous process by electroplating.

[0133] In addition, according to Figure 5 , the substrate 176 and the first protrusion 160 are made of different materials. For example, the substrate 176 can be made of copper, and the first protrusion 160 and the second protrusion 168 can be formed integrally (for example, formed of ZnV). In addition, Figure 5 An optional intermediate layer 178, such as a seed layer, is shown between the substrate 176 and the first protrusions 160 (see detail enlargement 123). The intermediate layer 178 can promote adhesion between the material of the substrate 176 and the material of the first and second protrusions 160, 168.

[0134] Figures 6 to 9is an image of a structure 150 of a package 100 according to an exemplary embodiment.

[0135] Figure 6 A front view of the first substructure 152 is shown, particularly showing the carpet-like arrangement of the first protrusions 160 . Figure 6 SEM (scanning electron microscope) images are shown.

[0136] Figure 7 is corresponding to Figure 6 , particularly showing the first protrusion 160 on the base 176. Figure 7 (and correspondingly, Figure 8 and Fig. 9 ) shows a TEM (transmission electron microscope) image.

[0137] Figure 8 Shows Figure 7 The details defined in 125.

[0138] Fig. 9 Shows Figure 8 Thus, the second protrusion 168 on the first protrusion 160 is also visible.

[0139] Combined, Figures 6 to 9 It is shown that the first protrusion 160 and the second protrusion 168 are arranged in a random manner over a continuous surface area. The dual-morphology adhesion promoter in the form of the first protrusion 160, the second protrusion 168 is implemented here as a ZnV layer with a total layer thickness of 0.2 μm. The second protrusion 168 can be implemented as Zn dendrites or crystallites and can have a size in the range of 10nm to 20nm. More specifically, the first protrusion 160, the second protrusion 168 is implemented here as a porous shell composed of vanadium oxide with traces of zinc.

[0140] More generally, exemplary embodiments may combine first protrusions 160 having macro-roughness with second protrusions 168 having nano-roughness. Typical dimensions of the macro-first protrusions 160 may be in the range of 100 nm to 1 μm, wherein the nano-roughness of the second protrusions 168 may correspond to typical dimensions in the range of 1 nm to 30 nm.

[0141] Fig.10 An undercut 151 of a first protrusion 160 of a structure 150 for a package 100 is shown according to an exemplary embodiment.

[0142] When one or more undercuts 151 are formed between the base 176 and the first protrusion 160, a very significant mechanical interlock can be obtained, thereby achieving very significant adhesion within the intermediate layer 164 (see Fig.10 on the right side of the ). Fig.10 The region with the undercut 151 is shown (see Fig.10 on the right side) and the area without the undercut 151 (see Fig.10 The presence of the undercut 151 corresponds to a hole geometry having a side angle of less than 90° (ie, forming the undercut 151).

[0143] Fig.11 The relationship between the vertical depth Rz of the first protrusions 160 of the structure 150 for the package 100 and the distance L between adjacent first protrusions 160 is schematically shown according to an exemplary embodiment. Fig.12 The corresponding experimentally captured images are shown.

[0144] The first substructure 152 according to an exemplary embodiment may be characterized in that the geometric factor Rz / L is greater than 0.2 (particularly in the range of 0.2 to 5). In this context, Rz may denote the height of the first protrusion 160, and L may denote the distance between adjacent peaks of the first protrusion 160. For example, the absolute value of Rz may be in the range of 0.1 μm to 10 μm, for example 1 μm.

[0145] It should be noted that the term "comprising" does not exclude other elements or features, and "one" or "an" does not exclude a plurality. Likewise, elements described in connection with different embodiments may be combined. It should also be noted that the reference numerals should not be interpreted as limiting the scope of the claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the processes, machines, manufactures, compositions of matter, devices, methods and steps described in the specification. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, devices, methods or steps within their scope.

Claims

1. A structure (150) for a package (100), the structure (150) comprising: · first substructure (152); and a second substructure (154) coupled to the first substructure (152) and being a composite material comprising filler particles (156) in a matrix (158); wherein the surface of the first substructure (152) has a surface profile including first protrusions (160) and first recesses (162), the first recesses (162) being configured to allow at least a portion of the filler particles (156) to at least partially enter the first recesses (162), thereby forming an intermediate layer (164), the intermediate layer (164) comprising the first protrusions (160) of the first substructure (152) and the filler particles (156) in the matrix (158) of the second substructure (154); Wherein, the surface of the first substructure (152) has a second protrusion (168) and a second recess (170) formed on the first protrusion (160) and the first recess (162); wherein the second recess (170) is sized such that at least a portion of the matrix (158) can at least partially enter the second recess (170) and is sized such that the filler particles (156) cannot enter the second recess (170).

2. The structure (150) of claim 1, wherein: The depths of the first protrusion (160) and the first recess (162) are in the range of 0.1 μm to 50 μm.

3. The structure (150) of claim 1, wherein: The depths of the first protrusion (160) and the first recess (162) are in the range of 0.1 μm to 10 μm.

4. The structure (150) of claim 1, wherein: The depths of the first protrusion (160) and the first recess (162) are in the range of 0.6 μm to 5 μm.

5. The structure (150) according to any one of claims 1 to 4, wherein: At least a portion of the filler particles (156) have a diameter (D) in a range of 10 nm to 10 μm.

6. The structure (150) according to any one of claims 1 to 4, wherein: At least a portion of the filler particles (156) have a diameter (D) in the range of 20 nm to 2 μm.

7. The structure (150) according to any one of claims 1 to 4, wherein: At least a portion of the filler particles (156) have a diameter (D) in a range of 50 nm to 1 μm.

8. The structure (150) according to any one of claims 1 to 4, wherein: The ratio between the depth of the first protrusions (160) and the distance (L) between the peaks (166) of adjacent first protrusions (160) is at least 0.

2.

9. The structure (150) according to any one of claims 1 to 4, wherein: A ratio between the depth of the first protrusions (160) and the distance (L) between the peaks (166) of adjacent first protrusions (160) is in the range of 0.2 to 5.

10. The structure (150) of claim 1, wherein: The second protrusions (168) and the second recesses (170) have a depth in the range of 1 nm to 100 nm.

11. The structure (150) of claim 1, wherein: The second protrusions (168) and the second recesses (170) have a depth in the range of 10 nm to 50 nm.

12. The structure (150) of claim 1, wherein: The second protrusions (168) and the second recesses (170) have a depth in the range of 10 nm to 30 nm.

13. The structure (150) according to any one of claims 1-4, 10-12, wherein: The first substructure (152) includes a base (176) on which a first protrusion (160) is formed.

14. The structure (150) of claim 13, wherein: The structure (150) includes at least one of the following features: The base (176) and the first protrusion (160) are made of the same material; The base (176) and the first protrusion (160) are made of different materials; The base (176) and the first protrusion (160) are in direct physical contact with each other; including an additional intermediate layer between the substrate (176) and the first protrusion (160); At least one undercut portion (151) is formed between the base body (176) and the first protrusion (160).

15. The structure (150) of claim 14, wherein: The additional intermediate layer is a seed layer; and / or The at least one undercut (151) is formed to improve mechanical interlocking and thereby adhesion within the intermediate layer (164), and / or the at least one undercut (151) corresponds to a hole geometry having a side angle less than 90°.

16. The structure (150) according to any one of claims 1-4, 10-12, 14-15, wherein: The filler particles (156) have a coefficient of thermal expansion value selected such that the presence of the filler particles (156) in the intermediate layer (164) reduces a mismatch between the coefficients of thermal expansion between the first substructure (152) and the second substructure (154).

17. The structure (150) according to any one of claims 1-4, 10-12, 14-15, wherein: The second protrusion (168) and the second recess (170) are configured as adhesion promoters.

18. The structure (150) of claim 17, wherein: The adhesion promoter is a morphological adhesion promoter.

19. The structure (150) of claim 18, wherein: The morphological adhesion promoter is a porous adhesion promoter.

20. The structure (150) according to any one of claims 1-4, 10-12, 14-15, 18-19, wherein: At least one of the first protrusions (160) and the second protrusions (168) are arranged in a random manner over a continuous surface area.

21. A package (100), comprising: At least one functional package body (102, 104, 110); An encapsulant (106) encapsulating at least a portion of the at least one functional package body (102, 104, 110); and ·The structure (150) according to any one of claims 1-20, which serves as an interface between the encapsulant (106) and at least a portion of the at least one functional package body (102, 104, 110), wherein the first substructure (152) forms a portion of the at least one functional package body (102, 104, 110) and the second substructure (154) forms at least a portion of the encapsulant (106).

22. The package (100) according to claim 21, wherein: The at least one functional package body (102, 104, 110) comprises at least one of the group consisting of a carrier (102) for carrying an electronic component (104), an electronic component (104), and a conductive contact element (110) for electrically coupling the electronic component (104) to the carrier (102).

23. The package (100) according to claim 21 or 22, wherein: The package (100) comprises at least one of the following features: The structure (150) is formed as an interface between the encapsulant (106) and a metal surface of the at least one functional package body (102, 104, 110); The package (100) is a power module.

24. A method of manufacturing a structure (150) for a package (100), wherein: The method comprises: · coupling the first substructure (152) to the second substructure (154); · configuring the second substructure (154) as a composite material comprising filler particles (156) in a matrix (158); · configuring the surface of the first substructure (152) to have a surface profile including first protrusions (160) and first recesses (162); and at least partially embedding at least a portion of the filler particles (156) in the first recesses (162) to form an intermediate layer (164) of filler particles (156) in the matrix (158) of the second substructure (154) and the first protrusions (160) of the first substructure (152); A second protrusion (168) and a second recess (170) are formed on the first protrusion (160) and the first recess (162), wherein the size of the second protrusion (168) and the second recess (170) is smaller than the size of the first protrusion (160) and the first recess (162); wherein the second recess (170) is sized such that at least a portion of the matrix (158) can at least partially enter the second recess (170) and is sized such that the filler particles (156) cannot enter the second recess (170).

25. The method according to claim 24, wherein: The method includes using the structure (150) as an interface between a second substructure (154) and at least a portion of a first substructure (152), thereby forming a package (100).

26. The method according to claim 25, wherein: The second substructure (154) is an encapsulation (106); and / or The at least a portion of the first substructure (152) is at least one of a carrier (102) and an electronic component (104).

27. The method according to any one of claims 24 to 26, wherein: The method includes forming at least one of a first protrusion (160) and a second protrusion (168) by electroplating.

28. The method according to any one of claims 24 to 26, wherein: The method includes forming a first protrusion (160) and a second protrusion (168) in a common process.

29. The method according to any one of claims 24 to 26, wherein: The method includes simultaneously forming a first protrusion (160) and a second protrusion (168).

Images