Inorganic encapsulant for electronic component with adhesion promoter

Abstract

A package includes an electronic component, an inorganic encapsulant encapsulating at least part of the electronic component, and an adhesion promoter between at least part of the electronic component and the encapsulant.

Claims

1. A package, comprising: an electronic component; an inorganic encapsulant encapsulating at least part of the electronic component; and an adhesion promoter that enhances adhesion between at least part of the electronic component and the encapsulant, wherein the adhesion promoter is a morphological adhesion promoter comprising a morphological structure having a plurality of openings.

2. The package of claim 1, wherein the encapsulant is a ceramic-based encapsulant or an inorganic polymer-based encapsulant.

3. The package of claim 1, wherein the encapsulant comprises at least one selected from the group consisting of: cement, concrete, gypsum, mortar, a silicon polymer, and an aluminum polymer.

4. The package claim 1, wherein the morphological adhesion promoter comprises at least one selected from the group consisting of: a metallic structure, an alloy structure, an alloy oxide structure, a chromium structure, a vanadium structure, a molybdenum structure, a zinc structure, a manganese structure, a cobalt structure, a nickel structure, a copper structure, a flame deposited structure, a roughened metal structure, and any alloy, alloy oxide, oxide, nitride, carbide, and selenide of said structures.

5. The package claim 1, wherein the plurality of openings comprises at least one selected from the group consisting of: pores, dendrites, and gaps between islands of a patterned structure.

6. The package of claim 1, wherein a material of the adhesion promoter is adapted for at least partially compensating a mismatch between the coefficients of thermal expansion of a material of the electronic component and a material of the encapsulant.

7. The package of claim 1, wherein the adhesion promoter forms an interlayer in an interface region between the encapsulant and the electronic component.

8. The package of claim 7, wherein at least one of: the interlayer provides a transition of porosity between the encapsulant and the electronic component; at least part of pores of the interlayer are at least partially filled with material of the encapsulant; and the interlayer has a thickness in a range between 30 nm and 500 nm.

9. The package of claim 1, further comprising a carrier on which the electronic component is mounted, wherein the carrier is at least partially encapsulated in the encapsulant, and wherein the carrier is at least partially covered by an adhesion promoter.

10. The package of claim 9, further comprising an electrically conductive contact element electrically coupling the electronic component with the carrier, wherein the electrically conductive contact element is at least partially encapsulated in the encapsulant, and wherein the electrically conductive contact element is at least partially covered by an adhesion promoter.

11. The package of claim 1, wherein the electronic component comprises at least one selected from the group consisting of: a semiconductor chip, a power semiconductor chip, an active electronic device, a passive electronic device, a sensor, an actuator, and a microelectromechanical system.

12. The package of claim 9, wherein the carrier is a leadframe made of copper.

13. The package of claim 10, wherein the electrically conductive contact element is a bond wire.

14. The package of claim 1, wherein the electronic component is a semiconductor chip having a metal pad.

15. The package of claim 14, wherein the metal pad is an aluminum or copper pad.

16. The package of claim 14, wherein along a vertical direction perpendicular to the metal pad, a coefficient of thermal expansion of the package is dominated by the encapsulant at a first vertical level, dominated by the metal pad at a second level, and dominated by the adhesion promoter at a third level between the first level and the second level.

17. The package of claim 14, wherein along a vertical direction perpendicular to the metal pad, an amount of material provided by the encapsulant continuously decreases and an amount of material provided by the adhesion promoter continuously increases between a first vertical level and a second vertical level, the second vertical level being closer to the metal pad than the first vertical level.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, which are included to provide a further understanding of exemplary embodiments and constitute a part of the specification, illustrate exemplary embodiments.

(2) In the drawings:

(3) FIG. 1 illustrates a cross-sectional view of a package according to an exemplary embodiment to be mounted on a mounting structure.

(4) FIG. 2 schematically illustrates an interface region with a morphological adhesion promoter between an electronic component and an inorganic ceramic-based encapsulant according to an exemplary embodiment.

(5) FIG. 3 is a plan view of a morphological adhesion promoter according to an exemplary embodiment comprising manganate.

(6) FIG. 4 is a plan view of a morphological adhesion promoter according to an exemplary embodiment comprising zinc-chromium alloy.

(7) FIG. 5 is a cross-sectional view of the morphological adhesion promoter according to FIG. 4.

(8) FIG. 6 is a plan view of a morphological adhesion promoter according to an exemplary embodiment comprising zinc vanadium alloy and oxide.

(9) FIG. 7 is a cross-sectional view of the morphological adhesion promoter according to FIG. 6.

(10) FIG. 8 is a plan view of a morphological adhesion promoter according to an exemplary embodiment comprising zinc molybdenum alloy and oxide.

(11) FIG. 9 is a plan view of a morphological adhesion promoter according to an exemplary embodiment comprising zinc-vanadium.

(12) FIG. 10 is a cross-sectional view of the morphological adhesion promoter according to FIG. 9.

(13) FIG. 11 shows a detail of the cross-sectional view of FIG. 10.

(14) FIG. 12 shows a detail of the cross-sectional view of FIG. 11.

(15) FIG. 13 shows a further detail of the morphological adhesion promoter according to FIG. 9 to FIG. 12 which shows a zinc vanadium seed layer as a starting layer for the final porous adhesion promoter layer.

(16) FIG. 14 illustrates a model of a porous morphological adhesion promoter according to an exemplary embodiment.

(17) FIG. 15 is a diagram illustrating a stress mean value along the vertical direction of the porous morphological adhesion promoter according to FIG. 14.

(18) FIG. 16 is a diagram illustrating a stress mean value along the vertical direction without porous morphological adhesion promoter, for comparison with FIG. 15.

DETAILED DESCRIPTION

(19) The illustration in the drawing is schematically and not to scale.

(20) Before exemplary embodiments will be described in more detail referring to the figures, some general considerations will be summarized based on which exemplary embodiments have been developed.

(21) According to exemplary embodiments, an encapsulant is provided comprising or consisting of an inorganic material—in particular ceramics (for example concrete)—combined with a—preferably morphological—adhesion promoter.

(22) Existing epoxy-based molding compounds have very high coefficients of thermal expansion (CTE) with limited yield strength. In addition, these thermosets may tend to crack along interfaces and in bulk. Furthermore, delamination at the interface may happen in such conventional approaches.

(23) Moreover, besides mechanical and thermomechanical limitations, existing polymer based encapsulation may have a limitation regarding thermal degradation and may start to degrade already at very low temperature of 200° C. Specific semiconductor materials (such as GaN, SiC or modern MOSFET generations) may however require much higher temperature stability of the respective package of up to 300° C. which cannot be achieved with conventional encapsulation materials, for example epoxy-based polymeric encapsulants.

(24) Conventional epoxy mold compounds may have inorganic fillers (for example SiO.sub.2) with high filler contents to reduce the CTE value of the bulk material. To increase the adhesion of the mold compound towards a semiconductor chip, leadframe and other interfaces, various adhesion promoter molecules may be added. In addition to the adhesion promoters, these mold compounds may comprise various different chemicals, such as flame-retardants. However, possible reactions between the different components at higher temperatures may lead to additional chemical species that may be dangerous for the package.

(25) Limitations of conventional encapsulants based on hydrocarbon-based encapsulation materials (epoxy, etc.) include their limited yield strength, high CTE and low temperature resistance, as such materials may decompose quickly at higher temperature.

(26) In order to overcome at least part of the above-mentioned and/or other shortcomings, an exemplary embodiment uses an inorganic encapsulation material, in particular a ceramic encapsulation material. Using ceramic-based inorganic materials (for example concrete) may offer a much lower CTE at much higher yield strength. Since concrete materials may be non-flammable non-polymers, additives such as flame retardants can be omitted, thus reducing the complexity of the encapsulation material. Additionally, concrete offers a far broader stability when it comes to higher temperatures of more than 300° C. Conventional mold compounds already show stability weakness at 200° C. Details of ceramic formulations of encapsulants used according to an exemplary embodiments and their solidification mechanism are shown in Table 1 below.

(27) TABLE-US-00001 TABLE 1 Table 1: Overview of ceramic formulations and inorganic polymer formulations and their different phases to interact with any of the adhesion promoters described in Table 3 Solid phase Liquid matrix Solidification Material phase in bulk of liquid phase Additives Concrete Soluble Al.sub.2O.sub.3, Formation of Concrete Ca-oxide SiO.sub.2, hydrates of 23iquefier, and Si-oxde Fe.sub.2O.sub.3 Ca-oxide, Super- phases Ca- plasticizer, (for example Aluminates, Stabilizer, Ca(OH).sub.2; Ca-Silicates Airtrap maximum former, concentration Accelerator 1.7 g/L in for water at solidifica- 20° C.) (*1) tion: CaCl.sub.2, carbonate, Na.sub.2CO.sub.3, aluminate, Tricalcium- aluminate, Inhibitor, Sealing agents Gypsum Soluble Ca- Formation of Ca-sulfate sulfate Ca-sulfate and its hydrates hydrates hydrates (for example CaSO.sub.4; maximum concentration 2 g/L in water) (*1) Mortar Soluble CaCO.sub.3, Formation of Ca-oxide CaOH hydrates of and Si-oxide and Ca-oxide, phases its further (for example hydrides solidifycation Ca (OH) .sub.2; with absorption maximum of CO.sub.2: concentration Ca(OH).sub.2 + 1.7 g/L in CO.sub.2 −> CaCO.sub.3 + water at H.sub.2O 20° C.) (*1) Silicon Silicate polymer Aluminum Aluminate polymer ((*1): Solvents: Besides water also alcohols and/or other solvents may be used)

(28) Table 2 shows different types of cements which may be used as ceramic-based encapsulant of a package of an exemplary embodiment.

(29) TABLE-US-00002 TABLE 2 Table 2: Examples for cement components used for concrete formulations Portland Siliceous Calcareous Slag Silica Property cement fly ash fly ash cement fume Silicon 21.9 52 35 35 85 to 97 oxide content (%) Aluminum 6.9 23 18 12 oxide (%) Iron 3 11 6 1 oxide (%) Calcium 63 5 21 40 <1 oxide (%) Magnesium 2.5 oxide (%) SO.sub.3 (%) 1.7

(30) Using a morphological adhesion promoter as a base for the ceramic encapsulation material may allow for efficiently improving intra-package adhesion within a package according to an exemplary embodiment.

(31) In embodiments, the ceramic based materials may be manufactured and processed as a mixture of solution and particles to encapsulate the electronic component(s). To ensure a proper interaction between the encapsulation material and a morphological adhesion promoter, the morphological adhesion promoter may be preferably applied before the application of the encapsulation material.

(32) At the time when the liquid encapsulation material is getting contact to the morphological adhesion promoter, the liquid part of the mixture, during application on the electronic component, may be able to penetrate into pores of the adhesion promoter layer. Possible morphological adhesion promoters which may be used according to exemplary embodiments are shown in Table 3. For all these morphological adhesion promoters the given pore sizes and layer thickness can be adapted to the respective encapsulation material by correspondingly adjusting deposition process parameters.

(33) Again referring to Table 3, the chromium, vanadium and molybdenum-based adhesion promoters may be formed by galvanic deposition of the corresponding inorganic material. Thus, the three mentioned adhesion promoters are all an inorganic morphological adhesion promoters with a sponge-like pore structure. A flame deposited adhesion promoter may be a porous silicon oxide layer deposited from a gas phase, for instance using a flame, and is also a morphological adhesion promoter. Rough copper can be created by a corresponding copper etching procedure of a copper layer which causes porosity of the surface of the etched copper layer, thereby producing this morphological copper-based adhesion promoter. In a similar way, aluminum oxide may be roughened. Such an aluminum oxide material may be formed by thermal oxidation of aluminum or by ALD (atomic layer deposition). What concerns a wet chemical etching process for an ALD layer, it should be mentioned that this is only an exemplary way of getting the layer porous. For instance, water vapor can be already enough to get the porous layer. In addition, aluminium oxide may be formed porous by Chemical Vapor Deposition (CVD) with specific gas composition of aluminium organyl in the chamber. Apart from this, also silicon nitride can be deposited porous with a specific ratio between TEOS (tetraethylsilane) and ammonia (NH.sub.3) and specific deposition conditions regarding concentration and temperature. By a subsequent wet etching procedure, the created aluminum oxide may be rendered porous, wherein the pores may for instance have a substantially columnar and/or substantially spherical shape.

(34) As an alternative to the mentioned inorganic morphological adhesion promoters, it is also possible to use an organic adhesion promoter, for instance silane.

(35) A liquid precursor or a liquid part of the encapsulation material may crystalize in a sponge layer or in pores of a morphological adhesion promoter through formation of a solid phase, for example for concrete formation of crystalline hydrates.

(36) During this solidification of the liquid phase in the porous morphological adhesion promoter sponge, the morphological adhesion promoter and the encapsulation material may form a mixture of fiber/encapsulation interlayer. Besides a strong adhesion, this interlayer enables a CTE adaption from the electronic component, carrier or substrate to the encapsulation material. The ratio between adhesion promoter volume fraction and encapsulation material volume fraction may continuously change within the formed interlayer. The average CTE of the nano-structured layer may change from CTE (electronic component, carrier or substrate) to CTE (encapsulation material) continuously, depending on the pore size and the porosity. Therefore, the formed interlayer (which may be composed of material of the morphological adhesion promoter and material of the encapsulant, with spatially varying percentages) may form a layer with a continuous change of the CTE value from the electronic component or device substrate to the encapsulation material. A CTE mismatch between electronic component or device substrate on the one hand and encapsulation material on the other hand, which may generate stress (in particular thermomechanical stress), may be partially or even entirely compensated. Together with the advantageously low-CTE characteristic of a ceramic encapsulation, this may lead to stress reduction or even minimization in the package.

(37) Besides adhesion promotion and stress reduction, the morphological adhesion promoter may also act as a corrosion barrier. Especially together with the ceramic encapsulation, the formed interlayer may act as a protection from water and oxygen.

(38) In particular in case of a morphological adhesion promoter using Cr, V, or Mo, the adhesion to the device surface can be made also via a seed layer of the actual adhesion promoter layer as a metallurgical contact. Such a seed layer may also act as a corrosion barrier.

(39) Table 3 shows an overview of morphological adhesion promoters which may be used according to exemplary embodiments:

(40) TABLE-US-00003 TABLE 3 Table 3: Overview of morphological adhesion promoters that may interact with liquid-phase encapsulation materials (other materials are possible in other embodiments, in particular: a metallic structure, an alloy structure, a chromium structure, a vanadium structure, a molybdenum structure, a zinc structure, a manganese structure, a cobalt structure, a nickel structure, a copper structure, a flame deposited structure, a roughened metal structure, in particular a roughened copper structure or a roughened aluminum oxide structure, and any oxide, nitride, carbide, and selenide of said structures) Adhesion Material Pore Layer Preparation/deposition promoter of layer size thickness process Cr ZnCr-oxide 1-500 nm 1-500 nm Galvanic and and ZnCr- electroless alloy deposition with including pulse plating and seed layer plating, or V ZnV-oxide 1-500 nm 1-500 nm constant current and ZnV- alloy including seed layer Mo ZnMo-oxide 1-500 nm 1-500 nm and ZnMo- alloy including seed layer Flame SiO.sub.2, 1-500 nm 1-500 nm Flame or plasma deposited Si—O—C deposition with precursors (*1) Rough Cu Etched Cu 1-500 nm 1-500 nm Anisotropic etching surface of Cu or its alloys at from grain boundaries (*2) various Cu alloys Al.sub.2O.sub.3 Al.sub.2O.sub.3 1-500 nm 1-500 nm Thermal oxidation rough of aluminum or deposition of Al.sub.2O.sub.3 from, gas phase (atom layer deposition); treatment with aqueous solutions to form sponge and dendrites (*1): Precursors: Tetraethylsilane, Hexamethyldisiloxane, Hexamethyldisilane, Ti-organyls (*2): Example Cu roughening with H.sub.2SO.sub.4/H.sub.2O.sub.2 etching with benzotriazole additive to enhance selectivity of etching to grain boundaries

(41) FIG. 1 illustrates a cross-sectional view of a package 100, which is embodied as a Transistor Outline (TO) package, according to an exemplary embodiment. The package 100 is mounted on a mounting structure 132, here embodied as printed circuit board, for establishing an arrangement 130.

(42) The mounting structure 132 comprises an electric contact 134 embodied as a plating in a through hole of the mounting structure 132. When the package 100 is mounted on the mounting structure 132, an electronic component 104 of the package 100 is electrically connected to the electric contact 134 via an electrically conductive carrier 102, here embodied as a leadframe made of copper, of the package 100.

(43) The package 100 thus comprises the electrically conductive carrier 102, the electronic component 104 (which is here embodied as a power semiconductor chip) adhesively (see reference numeral 136) mounted on the carrier 102, and an encapsulant 106 encapsulating part of the carrier 102 and part of the electronic component 104. As can be taken from FIG. 1, a pad on an upper main surface of the electronic component 104 is electrically coupled to the carrier 102 via a bond wire as electrically conductive contact element 110.

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

(45) For ensuring electrical insulation of the electronic component 104 and removing heat from an interior of the electronic component 104 towards an environment, an electrically insulating and thermally conductive interface structure 108 may be provided which covers an exposed surface portion of the carrier 102 and a connected surface portion of the encapsulant 106 at the bottom of the package 100. The electrically insulating property of the interface structure 108 prevents undesired current flow even in the presence of high voltages between an interior and an exterior of the package 100. The thermally conductive property of the interface structure 108 promotes a removal of heat from the electronic component 104, via the electrically conductive carrier 102 (of thermally properly conductive copper), through the interface structure 108 and towards a heat dissipation body 112. The heat dissipation body 112, which may be made of a highly thermally conductive material such as copper or aluminum, has a base body 114 directly connected to the interface structure 108 and has a plurality of cooling fins 116 extending from the base body 114 and in parallel to one another so as to remove the heat towards the environment.

(46) Although FIG. 1 shows a very specific packaging architecture, the use of the encapsulant 106 which will be described below in further detail is advantageous also for any other packaging architectures of packages 100, etc.

(47) As will be described below referring to FIG. 2, the encapsulant 106 may be a ceramic-based inorganic encapsulant material, for instance cement. Moreover, a morphological adhesion promoter 150 may be arranged between the electronic component 104 and the ceramic encapsulant 106, as will be described below referring to FIG. 2 as well.

(48) As indicated schematically by reference numeral 150′ in FIG. 1, it is possible that also at least part of the carrier 102 (in particular a portion of the carrier 102 in contact with the encapsulant 106) is covered by an adhesion promoter such as the adhesion promoter 150 covering at least part of the electronic component 104. Additionally or alternatively and as indicated schematically by reference numeral 150″ in FIG. 1, it is also possible that also at least part of the electrically conductive contact element 110 is covered by an adhesion promoter such as the adhesion promoter 150 covering at least part of the electronic component 104. By taking this measure, the stability of the package 100 may be further increased and the tendency of delamination within package 100 may be further suppressed.

(49) FIG. 2 schematically illustrates an interface region with morphological adhesion promoter 150 between electronic component 104 (for instance, the shown part of the electronic component 104 in FIG. 2 may be a pad, such as an aluminum or copper pad, on a semiconductor body) and inorganic ceramic-based encapsulant 106 according to an exemplary embodiment.

(50) As already mentioned above, the encapsulant 106 may comprise cement, concrete, or alternatively gypsum or mortar. Such a ceramic-based inorganic encapsulant 106 may have inherently non-flammable properties, so that the addition of non-flammable additives may be dispensable. This renders the encapsulant 106 simple in manufacture. In particular, the combination of a morphological adhesion promoter 150 and a ceramic encapsulant 106 may be highly advantageous. This ensures proper adhesion, keeps thermomechanical stress small, enables efficient heat removal, prevents corrosion, and ensures thermal stability in the presence of very high temperatures.

(51) For instance, the schematically illustrated morphological adhesion promoter 150 may be a roughened copper structure or a porous Zn/Cr layer having pores into which material of the encapsulant 106 (which may be at least partially liquid or flowable during manufacture) may penetrate. Roughening of a copper material may be accomplished for instance by a plasma treatment, by wet etching, and/or by a mechanical treatment.

(52) As shown in FIG. 2, the adhesion promoter 150 has a plurality of openings 160 in the form of pores with varying diameter. The material of the adhesion promoter 150 may be selected for partially or entirely compensating a mismatch of the coefficient of thermal expansion between the material of the electronic component 104 and the material of the encapsulant 106.

(53) Adhesion promoting interlayer 152 forms an interface between the encapsulant 106 and the adhesion promoter 150. For instance, a vertical thickness, d, of the interlayer 152 can be 100 nm. The interlayer 152 constitutes a continuous transient between material of the encapsulant 106 and material of the adhesion promoter 150, as will be described in the following in further detail: For manufacturing the structure shown in FIG. 2, it may be possible to form the encapsulant 106 on and in the adhesion promoter 150 by providing a mixture of a solution and particles in the solution, as a precursor of the encapsulant 106. During manufacture of the encapsulant 106, the solution may flow inside the pore type openings 160 of the morphological adhesion promoter 150. This liquid phase or flowable matrix may then be cured or solidified (for instance by hydration or polymerization) and may thus remain in a solid phase permanently within the pores of the morphological adhesion promoter 150. This results in an encapsulant 106 comprising a solid matrix 182 (formed on the basis of the previously liquid precursor) and filler particles 184 embedded in the matrix 182. When the morphological adhesion promoter 150 has been formed on the electronic component 104 before the encapsulating, it may be possible to contact the morphological adhesion promoter 150 with the solution as one of precursors of the encapsulant 106 in such a way that the solution penetrates into the openings 160 in the morphological adhesion promoter 150.

(54) With the structure shown in FIG. 2, it may be possible to combine proper adhesion promotion, reliable stress suppression, and provision of a strong corrosion barrier.

(55) Still referring to FIG. 2, the morphological adhesion promoter 150 defining interlayer 152 is arranged to increase the adhesion between encapsulant 106 and electronic component 104, reduce or smoothen a CTE mismatch between encapsulant 106 and chip 102 and suppress undesired corrosion. For this purpose, the morphological adhesion promoter 150 comprises the openings 160 with decreasing diameter from a region in which the package 100 purely consists of encapsulant material up to the electronic component 104. Thus, a liquid precursor used for manufacturing the ceramic-based encapsulant 106 may flow into the openings 160 during the manufacturing process and may contribute to a smooth transition of the coefficient of thermal expansion (CTE) along a vertical or z-axis direction which is indicated with reference numeral 190 in FIG. 2. At a vertical level 192, the CTE value is defined by material of the encapsulant 106 only. At a level 194, the CTE value is defined by material (in particular aluminum of a pad or silicon material of a semiconductor body) of the electronic component 104 only. However, from a vertical level of layer 198 up to another vertical level of layer 196, the amount of material provided by the encapsulant 106 continuously decreases while an amount of material of the adhesion promoter 150 continuously increases. While at vertical level 198, the CTE value is dominated by material of encapsulant 106, the CTE value is dominated by material of the adhesion promoter 150 at level 196. For instance, the porosity (i.e. a ratio between pore volume on the one hand and the sum of pore volume and solid adhesion promoter material volume on the other hand) of the interlayer 152 may be 10% at layer 196, whereas the porosity may be 90% at layer 198. In particular, variation and adjustment of porosity of morphological adhesion promoter 150 by tuning its morphology allows for a smooth CTE transition, compared to thermal mechanically disadvantageous jump functions of CTE at an abrupt interface between encapsulant 106 and electronic component 104. As a result, the CTE mismatch is smoothly changed along direction 190, which reduces thermal load inside of the package 100. Additionally, the morphology of the morphological adhesion promoter 150 promotes mechanical interlocking between encapsulant material and adhesion promoter material and increases the interior surface so as to enhance adhesion between material of encapsulant 106 and material of electronic component 104. By properly selecting the material of the adhesion promoter 150 and of the encapsulant 106, also the tendency of the package 100 of corroding during use in humid environment can be strongly suppressed. Therefore, a highly reliably package 100 can be obtained by an exemplary embodiment.

(56) The cement of the ceramic-based encapsulant 106 may reduce thermomechanical stress due to its highly advantageous CTE properties. Furthermore, the cement material with its crystalline structure may enhance mechanical stability of the package 100. Even more important, thermal stability of cement increases manufacturing and operation temperatures of the package 100 compared to conventional approaches. Moreover, cement material has an excellent thermal conductivity, as compared to other encapsulation materials.

(57) In particular in combination with the morphological adhesion promoter 150, an improved adhesion and a reduced tendency of delamination, as well as an increased tensile strength of the package 100 may be obtained.

(58) A skilled person will understand that the illustration of the pore structure in FIG. 2 is merely schematic and for illustrative purposes. The geometry of such a pore structure may broadly vary depending on the used materials and used processes.

(59) In the following, different embodiments of deposition layer porosity will be compared:

(60) FIG. 3 is a plan view of a morphological adhesion promoter 150 according to an exemplary embodiment comprising manganite. A flat structure is obtained, no pores.

(61) FIG. 4 is a plan view of a morphological adhesion promoter 150 according to an exemplary embodiment comprising zinc-chromium alloy and oxide on NiP. FIG. 5 is a cross-sectional view of the morphological adhesion promoter 150 according to FIG. 4. The shown embodiment corresponds to a porous structure on NiP. A sponge-like structure is obtained with features of characteristic size larger than 30 nm.

(62) FIG. 6 is a plan view of a morphological adhesion promoter 150 according to an exemplary embodiment comprising zinc vanadium alloy and oxide. The shown embodiment corresponds to ZnV on NiP. FIG. 7 is a cross-sectional view of the morphological adhesion promoter 150 according to FIG. 6. A structure with porous plates is obtained with features of characteristic size in a range between 5 nm and 50 nm.

(63) FIG. 8 is a plan view of a morphological adhesion promoter 150 according to an exemplary embodiment comprising zinc molybdenum alloy and oxide. The shown embodiment corresponds to ZnMo on NiP. A crystal structure is obtained with features of characteristic size much smaller than 30 nm

(64) FIG. 9 is a plan view of a morphological adhesion promoter 150 according to an exemplary embodiment comprising zinc-vanadium (Zn—V) on NiP. FIG. 10 is a cross-sectional view of the morphological adhesion promoter 150 according to FIG. 9. FIG. 11 shows a detail of the cross-sectional view of FIG. 10. FIG. 12 shows a detail of the cross-sectional view of FIG. 11. FIG. 13 shows a further detail of the morphological adhesion promoter 150 according to FIG. 9 to FIG. 12. The thickness of the morphological adhesion promoter 150 is about 200 nm. Zn dendrites or crystallites with typical dimensions in the range between 10 nm and 20 mm are obtained. A porous shell of vanadium oxide with zinc traces may have typical dimensions in a range between 10 nm and 20 nm. A shell pore size may be smaller than 10 nm. A seed layer of vanadium oxide with zinc traces may have dimensions of 20 nm.

(65) FIG. 14 illustrates a model of a porous morphological adhesion promoter 150 according to an exemplary embodiment. FIG. 15 is a diagram illustrating a stress mean value (vertical axis of the diagram) along the vertical direction (horizontal axis of the diagram) of the porous morphological adhesion promoter 150 according to FIG. 14. FIG. 16 is a diagram illustrating a stress mean value along the vertical direction without porous morphological adhesion promoter, for comparison with FIG. 15. Thus, FIG. 15 shows the stress minimized with porous adhesion promoter, and FIG. 16 is the reference of non-stress minimized without the porous adhesion promoter. FIG. 14 and FIG. 15 prove the compensation of the CTE (coefficient of thermal expansion) mismatch and the stress reduction obtained by exemplary embodiments.

(66) The simulated morphological adhesion promoter 150 shows that the configuration of FIG. 15 may result in a stress reduction and an adaptation of the coefficient of thermal expansion. More specifically, the illustrated simulation shows that the porous morphological adhesion promoter 150 acts as stress reduction at an interface between a mold compound and an electronic component. For instance, the stress may be reduced from 0.3 GPa to about 0.1 GPa, i.e. a factor of three of stress reduction at the interface between copper and mold compound may be achieved.

(67) It should be noted that the term “comprising” does not exclude other elements or features and the “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined. It should also be noted that reference signs shall not be construed 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 process, machine, manufacture, composition of matter, means, methods and steps described in the specification. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.