DE102016015883B3 - Spatially selective roughening of encapsulant to promote adhesion with a functional structure - Google Patents

Abstract

Electronic component (100), wherein the electronic component (100) comprises:• an electrically conductive carrier (102);• an electronic chip (104) on the carrier (102);• an encapsulation compound (106) comprising at least a part of at least one of the carrier (102) and the electronic chip (104);• a functional structure (108) covering a surface section of the encapsulation compound (106);• wherein at least part of the covered surface section of the encapsulation compound (106) is spatially selectively roughened • wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic chip (104) is exposed from the encapsulant (106) or wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic chip (104) is in direct contact with at least part of the functional structure (108),• wherein the electronic component (100) further comprises a discontinuity (120) a ufweise formed in the surface portion of the encapsulation compound (106) covered by the functional structure (108), wherein at least a portion of the selectively roughened surface (130) is adjacent to the discontinuity (120).

Description

General state of the art

technical field

Various embodiments relate generally to electronic components and methods of manufacturing an electronic component.

Description of the prior art

Conventional packages, such as molded structures, for electronic chips have evolved to a level where the package no longer significantly impedes the performance of the electronic chips. Such electronic chips may be mounted on a leadframe, and an opposite major surface of the electronic chips may be connected to the leadframe by a bonding wire. Such a conventional electronic chip can be compromised by its thermal insulation within the package.

For certain applications, packages are provided with two different encapsulants to provide two different properties (such as compressibility, softness, toughness, mechanical decoupling, magnetic properties, color, etc.). Ensuring a reliable connection between the different encapsulants can be challenging.

the DE 10 2013 220 880 A1 discloses an electronic assembly including an electronic chip on a carrier, an encapsulation structure with a discontinuity, a thermal interface structure, and a heat sink. the US 2014/0027891 A1 discloses a semiconductor device with a packaged chip. Semiconductor devices having a chip encapsulated by an encapsulant are also disclosed in US Pat US 2009/0039486 A1 and the US 2014/0197552 A1 described.

Thus, there is still room to improve electronic components in terms of reliability.

short version

There may be a need to provide a way to manufacture electronic devices with a simple processing architecture and with high reliability.

According to one embodiment, an electronic component (such as a semiconductor package) is provided, an electrically conductive carrier (such as a leadframe), an electronic chip (such as a semiconductor chip) on the carrier, an encapsulation compound (such as a molding compound), the encapsulates at least a portion of at least one of the carrier and the electronic chip, and a functional structure (e.g., functionalization for thermal conductivity, electrical insulation, optical transmittance, magnetic properties, stress decoupling, coloring, etc.) covering a surface portion of the encapsulant wherein at least part of the covered surface portion of the encapsulant is spatially selectively roughened, wherein at least part of a surface of the carrier that is opposite to the electronic chip is exposed from the encapsulant sse is or wherein at least a part of a surface of the carrier, which is opposite to the electronic chip, has direct contact to at least part of the functional structure, wherein the electronic component further has a discontinuity formed in the surface portion of the encapsulation compound through the functional structure is covered, with at least part of the selectively roughened surface being adjacent to the discontinuity.

According to another embodiment, a method of manufacturing an electronic component is provided, the method comprising mounting an electronic chip on an electrically conductive carrier, encapsulating at least a part of at least one of the carrier and the electronic chip by an encapsulant, forming a discontinuity in a surface portion of the encapsulant, spatially selectively roughening a surface portion of the encapsulant to thereby form a spatially selectively roughened surface, at least a portion of the selectively roughened surface being adjacent to the discontinuity, and covering at least a portion of the roughened surface of the encapsulant with a functional structure wherein at least a portion of a surface of the carrier that is opposite to the electronic chip is exposed from the encapsulant, or wherein at least a portion is a r surface of the carrier, which is opposite to the electronic chip, is in direct contact with at least a part of the functional structure, the discontinuity being formed in the surface portion of the encapsulation compound that is covered by the functional structure.

Furthermore, an electronic component is described, which includes an electronic chip, an encapsulation compound (for example a molding compound) and a functional structure (for example another molding compound, a thermal interface material, a film, a printing material) that covers a surface section of the encapsulation compound wherein at least a part of the covered surface portion of the encapsulation compound is selectively roughened, and wherein the electronic chip is at least partially encapsulated by at least one of the encapsulation compound and the functional structure.

Furthermore, a method for producing a component (in particular an electronic component) is described, the method comprising forming an encapsulation compound (in particular a molding compound) and covering a surface section of the encapsulation compound with a functional structure (in particular a thermal interface material), with only or exclusively a Section of the covered surface section is selectively and locally roughened (where an electronic chip is optionally at least partially encapsulated by at least one of the encapsulation compound and the functional structure).

In addition, a device for producing an electronic component with an encapsulation compound, which has a spatially selectively roughened surface, is described, the device comprising an encapsulation tool with a receiving space which is designed for forming an encapsulation compound, the encapsulation tool having a relation to the roughened surface of the encapsulant to be formed has inverse delimitation part of the roughened surface of the receiving space, so that in the case that a preform (e.g. in viscous, liquid or granular form) of the encapsulating compound is filled into the receiving space and solidified (or cured), the encapsulating compound is formed with the roughened surface in a region corresponding to the inverse roughened surface.

An exemplary embodiment has the advantage that a reliability of the mechanical coupling between an encapsulation compound and a functional structure formed thereon can be significantly improved by roughening at least part of a connecting surface of the encapsulating compound to which the functional structure is to be connected in a delamination-protected manner. Roughening a bonding surface of the encapsulant increases mutual bonding surface area and also provides additional support such that a clamping effect between encapsulant and functional structure can further suppress the tendency to delaminate under stress. This allows the reliability of the electronic device to be increased as a whole. It can thus be ensured that the function provided by the functional structure as part of the functionality of the electronic component can be reliably maintained for a long time without the risk of a loss of adhesion between the encapsulation compound and the functional structure. Adhesion is important for achieving sufficiently reliable maintenance of device function over the life of the electronic component (e.g. adhesion is important to ensure sufficient electrical insulation over the life of the package). A locally higher roughness can also increase a length of an isolation path.

Description of further exemplary embodiments

Further exemplary embodiments of the electronic components, the device and the methods are explained below.

In the context of the present application, the term "roughness" or "surface roughness" can refer in particular to a parameter that indicates or quantifies structural deviations of an actual surface from its ideal flat or planar shape in a direction of the normal vector. If these deviations are larger, the surface is rougher, if they are smaller, the surface is smoother. When these deviations are specifically increased by a certain treatment, the surface becomes roughened. A "roughness" of a surface can be defined and measured as the average roughness (Ra), which is the arithmetic mean of all distances of the profile from the center line (e.g. the measurement can be carried out according to DIN 4768). A roughness of the roughened surface against a surrounding non-roughened surface can be compared based on the average roughness (Ra). On a microscopic scale, a roughened surface can have microprotrusions spaced by microindentations. The protrusions mentioned may have a convex shape, a concave shape or a mixture thereof, depending on the roughening procedure for creating the roughened surface.

In one embodiment, the roughened surface of the encapsulant has a uniform or uniform roughness profile. A uniform and sufficiently pronounced roughness profile (such as in 11 shown) has the advantage of a significant and homogeneous Improving the adhesion reliability between the encapsulant and the structure.

In one embodiment, the roughened surface of the encapsulation compound has a roughness (Ra) of at least 1 μm, in particular in a range between 1 μm and 10 μm, more particularly in a range between 2 μm and 4 μm. The selection of these parameters is the result of a trade-off between adhesion reliability on the one hand and detachability on the other. After the electronic component has been molded (eg, by transfer molding or compression molding), it is necessary to remove the manufactured electronic component from the mold. Excessive roughness makes such extraction difficult (without additional effort). High roughness can cause problems, especially at the side edges, as well as at positions where two mold tools abut. At such positions, it is technically preferable to avoid excessive roughness. In addition, the chip carrier (chip contact element, heat sink, etc.) should preferably remain free of encapsulation compound (mold burrs), which can be achieved by a small degree of roughness at such positions. However, in order to obtain adequate reliability of the electronic components with regard to reliable adhesion of the functional structure and the encapsulation compound, a sufficiently pronounced roughness is desired. The roughness of the roughened surface can be significantly greater than a natural or inherent degree of roughness of an encapsulant resulting from a common manufacturing procedure such as molding. However, those skilled in the art will understand that such natural or non-specific roughness, which may range between 0.4 µm and 0.8 µm when using molding (such as compression molding or transfer molding), is not to be considered a roughened surface , since the latter term implies a defined roughening procedure. In other words, a roughened surface can be formed by performing a roughening procedure applied to a surface portion of the encapsulant to be roughened.

The electronic component includes a discontinuity formed in that surface portion of the encapsulation compound that is covered by the functional structure. For example, such a discontinuity may be one or more cuts and/or one or more indentations. However, a discontinuity can also be formed by a step. The discontinuity may be arranged as an annular structure extending along the encapsulant, particularly extending around an entire exposed surface of a carrier. However, it is also possible that the discontinuity extends only partially around the carrier in a circumferential direction. Multiple separate discontinuities may be formed around the support, for example unconnected portions of a circle or multiple annular structures around the support. While the roughened surface may provide a large number of (particularly ordered or random) micropits, the discontinuity may form a single or a small number of macroscopic pits. In other words, dimensions of one or more substructures of a discontinuity in a surface plane of the encapsulation mass and perpendicular to this surface plane can be significantly larger than (in particular at least three times as large, more precisely at least 10 times as large as) corresponding dimensions of one or more substructures of the roughened surface in the surface plane of the encapsulant and perpendicular to that surface plane. By providing a discontinuity in addition to the roughened surface, the tendency for the functional structure (particularly a thermal interface structure) to delaminate from the encapsulant can be effectively reduced. Delamination can lead to separation between the two materials and degrade performance (e.g., insulation, corrosion, contamination, moisture, optical artifacts, mechanical integrity).

In one embodiment, the discontinuity is in the form of an annular depression in that surface section of the encapsulation compound that is covered by the functional structure. Correspondingly, the method can further comprise forming a discontinuity, in particular an annular depression, in the encapsulation compound adjacent to, in particular surrounding, the roughened surface portion of the encapsulation compound. Thus, in particular the path length along which a leakage current must propagate for short-circuiting the electronic component can be significantly increased by a ring-like depression that surrounds the entire carrier. Thus, the electrical breakdown voltage of the electronic component or package can be made very high.

In one embodiment, the roughened surface of the encapsulant is located adjacent to, in particular surrounding, at least a portion of the discontinuity. More specifically, the roughened surface may selectively surround only the discontinuity, ie it may be provided alone in a direct vicinity of the discontinuity, whereas more distant surface portions of the encapsulant will have a smaller roughness may have unity or may be smoother than the locally roughened surface. This has proven to be a highly effective means of increasing the adhesive strength between the encapsulant and the functional structure attached or formed thereon. A higher roughness increases the surface area between the two structures. This can also lead to an increase in a length of an electrical path and ultimately to a higher breakdown voltage or a smaller package size.

In one embodiment, the roughened surface of the encapsulant has a locally higher roughness than another lower roughness on a remaining (e.g., the entire remaining) surface of the encapsulant. In other words, the roughened surface can have a roughness value (in particular a value Ra) that is greater than a roughness value in other adjacent or neighboring surface sections of the encapsulation compound.

In one embodiment, the method includes treating the previously roughened surface of the encapsulant (i.e., post-roughening treatment) with a plasma (e.g., a chemical plasma). Examples of suitable plasma treatments are treatment by an argon plasma, an oxygen plasma, a hydrogen plasma, etc. and mixtures thereof additional submicron roughness of all exposed encapsulant surfaces can be achieved. Treating the roughened surface with a plasma prior to bonding the roughened surface of the encapsulant to the functional structure has been found to be able to activate the roughened surface, further increasing surface adhesion and further promoting secure bonding between the encapsulant and the structure. For example, surface activation can generate active OH groups on the roughened surface (and preferably also on adjacent surface sections), which further promotes delamination-free behavior of the encapsulation compound/functional structure arrangement even under mechanical and/or thermal stress. While roughening can be a localized treatment of only a portion of the surface of the encapsulant, a plasma treatment can be spatially non-specific and performed on the entire surface of the encapsulant.

In addition or as an alternative to the plasma treatment described, it is possible to clean the roughened surface of the encapsulation compound after roughening and before connecting to the functional structure. This additionally promotes delamination-free adhesion of the functional structure to the encapsulation compound.

Both plasma treatment and cleaning, in addition to roughening, are considered to reduce the tendency for the functional structure to delaminate from the encapsulant under stress applied to the electronic component. Such stress may be the result of autoclaving (as a stress test), high temperature storage (as a stress test), and/or heat generation of the packaged electronic chip during operation. In all three cases, a strain can result. Environmental stress accelerates aging of the interface surface.

With regard to a particularly advantageous process sequence, forming the encapsulation mass (in particular by molding) with a roughened surface can be followed by pre-annealing to remove moisture. A plasma activation and/or a cleaning process can then be carried out. The functional structure can then be formed, for example by a further molding process.

In one embodiment, the roughening is performed during (and thus simultaneously with) the encapsulation by using an encapsulation tool having a roughened inner tool surface with a shape inverse to the shape of the roughened surface of the encapsulant produced with the encapsulation tool. This is highly preferred since forming the roughened surface simultaneously with the encapsulation process eliminates the need for a separate roughening process. Thus, the manufacturing process can be accelerated. In a preferred embodiment, the encapsulation is achieved by molding using a mold tool as the encapsulation. In such a scenario, a portion of an interior surface of the mold tool that defines the shape of the electronic component to be manufactured may be fabricated with a pattern that is negative or inverse to the pattern or shape that defines the roughened surface of the encapsulant. Such a procedure also allows a precise definition of the surface topology of the roughened surface.

Correspondingly, the discontinuity can be eliminated by encapsulation with an encapsulation tool be formed, which has an inverse discontinuity compared to the discontinuity of the encapsulant produced with the encapsulation tool.

In another embodiment, the roughening after the encapsulation is carried out in particular by laser machining or a mechanical treatment. Accordingly, the discontinuity can be formed by laser processing or mechanical treatment. Laser processing can roughen one or more selective surface portions of the encapsulant simply by moving a laser device across appropriate surface portions of the encapsulant. As an alternative process of roughening after encapsulation without laser processing, mechanical roughening is possible. In such an embodiment, a surface of the encapsulant may be roughened by a mechanical treatment such as gouging or grinding.

In a particular embodiment, only a surface portion of the encapsulant adjacent to (particularly surrounding) a discontinuity is selectively roughened, since such a surface portion is considered to have the most significant impact on the lamination strength between the encapsulant and the functional structure. In order to further increase the protection against undesired delamination of the functional structure from the encapsulation mass, optionally also a whole or a partial surface of the discontinuity can be roughened, for example a bottom surface of a cut-type discontinuity. Roughening of at least a portion of the surface of a discontinuity can be accomplished in the same procedure by which surface roughening of the encapsulant outside the discontinuity is accomplished. For example, a mold may be provided correspondingly with an inverse structure with respect to a roughening surface of the encapsulant next to the position of the mold having a shape inverse to the discontinuity.

In one embodiment, at least part of the surface section of the carrier that is covered by the functional structure is roughened. Additional roughening of a connection surface of the carrier, which is to be covered by the functional structure, can further improve protection against delamination of the functional structure.

In one embodiment, the functional structure is an electrically insulating and thermally conductive interface structure, i. H. it is constructed of thermal interface material (TIM). A thermal interface material can help dissipate heat from the electronic die during operation of the electronic component. Such an embodiment has the advantage that the reliability of the thermal coupling between an encapsulation compound and an electrically conductive carrier on the one hand and an electrically insulating and thermally conductive interface structure on the other hand can be significantly improved by the surface roughening of the encapsulation compound in a surface section surrounding the carrier. This measure can reliably prevent an undesired mechanical delamination of the thermal interface structure from the encapsulation compound due to the enlarged and more complex contact surface between these two elements. The formation of electrical leakage currents from an outside of the electronic component or package to the encapsulated and surface-covered carrier via a gap between the encapsulant and the thermal interface structure can thereby also be made highly improbable, improving the electrical performance of the electronic component. In addition, a reliable connection between the encapsulation compound and the carrier on the one hand and the thermal interface structure on the other hand significantly improves the thermal performance of the electronic component or package, since heat generated by the encapsulated electronic chip during operation of the electronic component can be effectively dissipated via the thermal interface structure , for example to a heat dissipation body that can be attached externally to the thermal interface structure.

In one embodiment, a through hole extends at least through the encapsulation compound and the functional structure, so that a fastener (such as a screw or bolt) for fastening the electronic component, for example in the case of a TIM-type functional structure to a heat dissipation body, through the through hole can be led. In one embodiment, the fastener may form part of the electronic component. Mounting the electronic component to a heat-dissipating body or any other body by a fastener such as a screw is easy and inexpensive.

In one embodiment, the electronic component includes a clip used to connect the electronic component to another body, such as a heat waste body, is designed. Such a clamp can be designed so that the packaged thermal interface coating chip carrier assembly can be clamped against the heat dissipation body without having to form a through hole. Although the effort of connecting a heat dissipation body to the rest of the electronic component by a clip is somewhat higher than by a fastener such as a screw, it is nevertheless advantageous, particularly for high power applications. In an embodiment in which a clamp is used, it has proven to be advantageous to design the functional structure with a convex surface facing the heat dissipation body. With such a configuration, when pressure is applied by the clip, the convex surface deforms to a substantially planar surface, thereby ensuring full surface contact between the interface structure and the discharge body with no air gaps.

The functional structure can be a foil to be connected to the rest of the electronic component by lamination. As an alternative to this, it is possible to form the functional structure by encapsulation, printing, application, deposition.

For example, the functional structure can have a thickness in a range between 10 μm and 1000 μm, in particular in a range between 50 μm and 500 μm. For example, the thermal conductivity of the material of the functional structure can be in a range between 1 W m −1 K −1 and 30 W m ⁻¹ K ⁻¹ , in particular in a range between 2 W m ⁻¹ K ⁻¹ and 8 W m ⁻¹ K ^-1 lie. The thermal conductivity of the material of the thermal interface structure (as an embodiment of the functional structure) can be higher than the thermal conductivity of the material of the encapsulation compound. For example, the thermal conductivity of the material of the encapsulation mass can be in a range between 0.2 W m ^-1 K ^-1 and 6 W m ^-1 K ^-1 , in particular in a range between 0.8 W m ^-1 K ^-1 and 2 W m ^-1 K ^-1 . For example, the thermal interface structure material may be a silicone-based material (or may be based on any other resin-based material and/or combinations thereof), which may include filler particles to improve thermal conductivity. For example, such filler particles may comprise or consist of alumina (and/or silicon nitride, boron nitride, aluminum nitride, diamond, etc.).

In one embodiment, the material of the encapsulation mass and/or the functional structure can be based on flat structures, pellets, granules and/or liquid.

In another embodiment, the functional structure is an optically transparent structure. Accordingly, the electronic chip can be designed to emit and/or receive electromagnetic radiation, and the functional structure can be transparent to the transmitted electromagnetic radiation. Such an embodiment is in 15 shown. In order to promote reliable adhesion between the optically transparent structure and the encapsulation compound, it can be advantageous to selectively roughen at least part of a bonding surface of the encapsulation compound to be bonded to the optically transparent structure.

In yet another embodiment, the functional structure is a magnetic structure, in particular a permanent magnetic structure, more precisely a ferromagnetic structure. For example, the electronic chip can be a sensor chip and the functional structure can be magnetic to generate a magnetic field acting on the sensor chip. Such an embodiment is in 15 shown. In order to promote reliable adhesion between the magnetic structure and the encapsulation compound, it can be advantageous to selectively roughen at least part of a bonding surface of the encapsulation compound to be bonded to the magnetic structure.

In yet another embodiment, the functional structure is designed to provide mechanical decoupling of a microelectromechanical structure (MEMS). In such a MEMS, which may include a moveable element, it may be necessary to mechanically decouple a particular element from another element. Advantageously, this can be achieved with a low modulus of elasticity.

In one embodiment, the encapsulation compound is a first molding compound, and the functional structure is a second molding compound that differs from the first molding compound in at least one material and/or physical property. By roughening a surface section of a molding compound, the adhesion of another molding compound to it can be improved.

In one embodiment, the localized formation of the roughened surface can be achieved in only a portion of the surface of the encapsulant by using a roughening process applied only to that portion of the surface of the encapsulant Encapsulation works. For example, laser processing can be performed in which the roughening laser beam impinges only on the portion of the surface of the encapsulant to be roughened, but not on other surface portions of the encapsulant. In another example, a mechanical roughening process may be performed, in which the roughening mechanical treatment is performed only on the portion of the surface of the encapsulant to be roughened, but not on other surface portions of the encapsulant. In yet another example, a chemical roughening process can be performed, in which the roughening chemical treatment is performed only on the portion of the surface of the encapsulant to be roughened, but not on other surface portions of the encapsulant (which may be protected from the chemical roughening by a protective layer , which protects certain surface regions of the encapsulant from roughening and which can be removed after the roughening process).

In one embodiment, the device further comprises a functional structure formation tool configured to form a functional structure covering a surface portion, including the roughened surface, of the formed encapsulant. Such an embodiment is in 6 shown. For example, a compression molding tool can be implemented as a functional structure formation tool. After the encapsulation compound has been produced with the exclusively partial and thus spatially selectively roughened surface section compared to a smoother adjoining remaining surface of the encapsulation compound in the encapsulation tool, a preform of the functional structure can be placed in the functional structure training tool in order to also cover the roughened surface of the encapsulation compound, so that adequate adhesion is obtained as a result of the increased bonding surface thanks to the roughening.

In the foregoing description, three examples (TIM, optically transparent material, magnetic material) have been presented to reliably connect structures to the encapsulant to increase the functionality of the manufactured electronic components or package while ensuring reliability. However, embodiments of the invention are not limited to these three examples, but also cover other applications in which a functional structure (e.g. thermally functional, electrically functional, optically functional, magnetically functional, etc.) with the encapsulation mass with reliable protection against undesired delamination is to be connected. This applies in particular to a scenario in which two molding compounds with different properties are to be combined, with the encapsulation compound being implemented as a first molding compound in such an embodiment and the functional structure being implemented as a second molding compound. A main point of such embodiments can then be seen in the roughening of a surface of the first molding compound before it is connected to the second molding compound. Dual molding may be performed to combine two different material properties provided by the first molding compound and the second molding compound. Examples of the two different material properties are the property pairs "magnetic - non-magnetic", "transparent - opaque", "expensive - cheap", "thermally conductive - poorly thermally conductive", "hard - soft".

Alternatively, however, it is also possible for the second encapsulation compound to be a different encapsulation compound and not a molding compound. For example, it is possible for the second encapsulant to be coated, cast, printed, molded, and so on. The same applies to the first encapsulation compound. In an exemplary further application, the separation between the first encapsulant and the second encapsulant (particularly when a second encapsulant is applied, cast, printed, etc. and not formed by molding) is for mechanical decoupling. For example, this may be beneficial in a pressure sensor or in a microelectromechanical system (MEMS) (such as a microphone or an accelerometer).

In one embodiment, the carrier comprises or consists of a leadframe. A leadframe can be a metal structure within a chip package designed to carry signals to the outside of the electronic chip and/or vice versa. The in-package electronic chip or electronic component may be attached to the leadframe, and then bonding wires for electronic chip attachment pads may be provided to terminals of the leadframe. The leadframe can then be molded into a plastic housing or other encapsulation compound. Outside of the leadframe, a corresponding section of the leadframe can be cut out, separating the corresponding terminals. Prior to such a cut, other procedures such as coating, final inspection, packaging, etc. may be performed as known to those skilled in the art. Alternative chip carriers that can be used for other embodiments can be any interposer, such as a substrate, a ceramic substrate, a laminar substrate, a DCB (Direct Copper Bonded Substrate), an IMS (Insulated Metal Substrate), a PCB (printed circuit board), and so on. Chip embedding is also an option.

In one embodiment, the electronic component further comprises the aforementioned heat dissipation body attached or to be attached to the interface structure for dissipating heat generated by the electronic chip during operation of the electronic component. For example, the heat dissipation body can be a plate of a suitably thermally conductive body, such as copper or aluminum or graphite, diamond, composite material and/or combinations of the mentioned and/or other materials, which can have cooling fins or the like Continue to promote dissipation of heat that can be conducted thermally from the electronic chip on the chip carrier and the interface structure for heat dissipation body. The dissipation of heat via the heat dissipation body can be further promoted by a cooling fluid, such as air or water (more generally a gas and/or a liquid), which can flow along the heat dissipation body outside of the electronic component.

In one embodiment, the electronic component is designed for double-sided cooling. For example, a first interface structure may thermally couple the encapsulated die and carrier to a first heat dissipation body, while a second interface structure may thermally couple the encapsulated die and carrier to a second heat dissipation body. In this case, two roughened surface portions of the encapsulant can be provided.

In one embodiment, the electronic chip is designed as a power semiconductor chip. Thus, the electronic chip (such as a semiconductor chip) can be used for power applications, for example in the automotive field, and can contain, for example, at least one insulated-gate bipolar transistor (IGBT) and/or at least one transistor of another type ( such as MOSFET, JFET, etc.) and/or have at least one integrated diode. Such integrated circuit elements can be constructed, for example, using silicon technology or based on semiconductors with a wide band gap (such as silicon carbide, gallium nitride or gallium nitride on silicon). A power semiconductor chip may include one or more field effect transistors, one or more diodes, inverter circuits, half bridges, full bridges, drivers, logic circuits, other devices, and so on.

In one embodiment, the electronic chip experiences a vertical current flow. The packaging architecture according to embodiments of the invention is particularly suitable for high power applications where vertical current flow is desired, i. H. a current flow in a direction perpendicular to the two opposite main surfaces of the electronic chip, one of which is used for mounting the electronic chip on the carrier.

In embodiments, the electronic component may be configured as a half bridge, a cascode circuit, a circuit formed by a field effect transistor and a bipolar transistor connected in parallel, or a power semiconductor circuit. The packaging architecture according to exemplary embodiments is therefore compatible with the requirements of very different circuit concepts.

In one embodiment, the electronic component is configured as one of the group consisting of a power module connected to a leadframe, a Transistor Outline (TO) electronic component, a Quad Flat No Leads Package (QFN) electronic component ), a Small Outline Electronic (SO) component, a Small Outline Transistor (SOT) electronic component, and a Thin More Outline Package (TSOP) electronic component. Therefore, the electronic component according to an embodiment is fully compatible with standard packaging concepts (particularly fully compatible with standard TO packaging concepts) and outwardly appears like a conventional electronic component that is highly user-friendly. In one embodiment, the electronic component is configured as a power module, e.g. B. a molded power module designed. For example, one embodiment of the electronic component may be an intelligent power module (IPM).

A semiconductor substrate, preferably a silicon substrate, can be used as the substrate or wafer that forms the basis of the electronic chip. Alternatively, a silicon oxide or other insulator substrate may be provided. It is also possible to implement a germanium substrate or III-V semiconductor material. For example, embodiments can be implemented in GaN or SiC technology.

A plastic material or a ceramic material can be used for the encapsulation. The encapsulant may include an epoxy material. Filler particles (e.g. SiO ₂ , Al ₂ O ₃ , Si ₃ N ₄ , BN, AlN, diamond etc.), for example to improve thermal conductivity, can be embedded in an epoxy-based matrix of the encapsulant.

Furthermore, embodiments may use standard semiconductor processing techniques, such as appropriate etching technologies (including isotropic and anisotropic etching technologies, in particular plasma etching, dry etching, wet etching), patterning technologies (which may involve lithographic masks), deposition techniques (such as chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), sputtering, etc.).

In one embodiment, the interface structure can be provided with an adhesive layer for adhering to the electronic component and/or the discharge body. It is possible to provide such an interface structure with a removable protective film that can be removed before the interface structure is adhered.

The above and other objects, features and advantages will be apparent from the following description and appended claims when read in conjunction with the accompanying drawings, in which like parts or elements are designated by like reference numerals.

character list

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

• veranschaulicht 1 gemäß einem Ausführungsbeispiel der Erfindung eine Querschnittsansicht einer elektronischen Komponente, die als eine Leistungshalbleiterpackung mit einer thermischen Grenzflächenstruktur ausgeführt ist, die eine Fähigkeit zur Wärmeabfuhr bereitstellt.
• Veranschaulicht 2 eine dreidimensionale Vorderansicht und Rückansicht der elektronischen Komponente gemäß 1.
• Veranschaulicht 3 gemäß einem Ausführungsbeispiel der Erfindung ein Verkapselungswerkzeug einer Herstellungseinrichtung und einen Teil einer elektronischen Komponente vor Anbringen einer thermischen Grenzflächenstruktur.
• Veranschaulicht 4 eine detaillierte Ansicht eines Oberflächenabschnitts einer Verkapselungsmasse mit einer lokal begrenzten aufgerauten Oberfläche, die eine gemäß 3 hergestellte Diskontinuität umgibt.
• Veranschaulichen 5 und 6 gemäß einem Ausführungsbeispiel der Erfindung eine Prozedur zum Verbinden einer thermischen Grenzflächenstruktur mit einem Rest einer elektronischen Komponente unter Verwendung einer Herstellungseinrichtung.
• Veranschaulicht 7 gemäß einem Ausführungsbeispiel der Erfindung eine Laservorrichtung und einen Teil einer elektronischen Komponente vor Anbringen einer thermischen Grenzflächenstruktur.
• Veranschaulicht 8 eine detaillierte Ansicht eines Oberflächenabschnitts einer Verkapselungsmasse mit einer aufgerauten Oberfläche, die eine gemäß 7 hergestellte Diskontinuität umgibt. Veranschaulicht 8A eine detaillierte Ansicht eines Oberflächenabschnitts einer Verkapselungsmasse mit einer aufgerauten Oberfläche, die eine Diskontinuität umgibt, und an der Bodenoberfläche der Diskontinuität, die gemäß 3 oder gemäß 7 hergestellt werden kann.
• Zeigen 9 bis 11 Charakteristika von Oberflächentopologien einer Verkapselungsmasse gemäß unterschiedlichen Herstellungsverfahren.
• Veranschaulichen 12 und 13 Querschnittsansichten von elektronischen Komponenten mit Wärmeabfuhrkörpern an einer thermischen Grenzflächenstruktur.
• Veranschaulicht 14 eine Querschnittsansicht einer elektronischen Komponente, die als eine Packung einer lichtemittierenden Diode mit einer optisch transparenten Formstruktur ausgeführt ist, die eine Fähigkeit zu optischer Transmission bereitstellt.
• Veranschaulicht 15 eine Querschnittsansicht einer elektronischen Komponente, die als eine Sensorpackung mit einer magnetischen Formstruktur ausgeführt ist, die eine Fähigkeit zur Erzeugung eines Magnetfeldes bereitstellt.

In the drawings:

• illustrated 1 10 is a cross-sectional view of an electronic component embodied as a power semiconductor package with a thermal interface structure that provides heat dissipation capability, according to an embodiment of the invention.
• illustrated 2 a three-dimensional front view and rear view of the electronic component according to FIG 1 .
• illustrated 3 according to an embodiment of the invention, an encapsulation tool of a manufacturing facility and a portion of an electronic component prior to attachment of a thermal interface structure.
• illustrated 4 a detailed view of a surface portion of an encapsulant with a localized roughened surface, the one according to 3 manufactured discontinuity surrounds.
• Illustrate 5 and 6 According to an embodiment of the invention, a procedure for connecting a thermal interface structure to a remainder of an electronic component using a manufacturing facility.
• illustrated 7 according to an embodiment of the invention, a laser device and part of an electronic component before attachment of a thermal interface structure.
• illustrated 8th a detailed view of a surface portion of an encapsulant with a roughened surface, the one according to 7 manufactured discontinuity surrounds. illustrated 8A FIG. 12 is a detailed view of a surface portion of an encapsulant with a roughened surface surrounding a discontinuity and at the bottom surface of the discontinuity shown in FIG 3 or according to 7 can be made.
• Demonstrate 9 until 11 Characteristics of surface topologies of an encapsulant according to different manufacturing processes.
• Illustrate 12 and 13 Cross-sectional views of electronic components with heat dissipation bodies at a thermal interface structure.
• illustrated 14 Figure 12 is a cross-sectional view of an electronic component embodied as a light emitting diode package with an optically transparent molded structure that provides optical transmission capability.
• illustrated 15 Figure 12 is a cross-sectional view of an electronic component embodied as a sensor package with a magnetic mold structure that provides a magnetic field generation capability.

Detailed description

The illustration in the drawing is schematic and not to scale.

Before embodiments are described in more detail with reference to the figures den, some general considerations are briefly summarized, on the basis of which the exemplary embodiments were developed.

According to an embodiment of the invention, selective package roughening may be performed for improved adhesion and/or for reliably providing another function (such as insulation, thermal coupling, etc.) of a functional structure to an encapsulant. For this purpose, specifically a bonding surface (or part thereof) of the encapsulation compound can be selectively roughened during and/or after its manufacture.

The provision of a thermally conductive insulation or thermally conductive interface material (TIM) as an example of a functional structure of electronic components or packaging, such as molded power devices, is often done by an end customer. Such an approach is expensive and limits the performance of the package or application. External isolation performs this function using a packing feature. The TIM layer should be delamination free throughout the life of the pack to ensure the pack meets the requirements of an appropriate security rating. For example, the dielectric strength of the manufactured electronic component should be at least 2.5 kV in certain power applications. A TIM structure can also provide the function of being compressible in addition to its heat dissipation function.

Lateral direction isolation can be conventionally realized by a fan-out approach, i. H. the insulating layer may be larger than the package or chip contact element. Insulation according to a fan-in approach means that it must be ensured by adequate adhesion between a molding compound (or other encapsulating compound) and the TIM layer (or other structure).

According to one embodiment of the invention, there is provided a selectively roughened molded package (more generally an electronic component with a roughened surface of a (preferably spatially limited) surface region of an encapsulant that is covered by a functional structure such as a thermal interface structure), preferably, although not necessarily, in combination with post-roughening plasma surface activation to obtain adequate adhesion between package and TIM material. Such an embodiment has the advantage of providing the possibility of parallel processing, which also results in low manufacturing costs. Compared to another embodiment in which the roughening is achieved by laser roughening or mechanical roughening, roughening during encapsulation allows for the omission of a certain separate process step. Advantageously, such an embodiment does not entail any risk of undesired carbonization of a transfer molding compound.

A key aspect of an embodiment of the invention is the provision of a molded power package (or module) with selective roughening of the mold surface to achieve improved adhesion (resulting in a delamination-free electronic component or package) between the insulating layer and the molding compound Performance can be combined with a high insulation security and thus a high dielectric strength of a power device or any other electronic component package.

An advantageous aspect of an embodiment of the invention is therefore the provision of a molded power device with selective roughening of the molding compound as the encapsulant for improved adhesion (i.e. a substantially delamination-free characteristic) between the attached structure (such as an insulating layer, more specifically a thermally conductive and electrically insulating one thermal interface material) and the molding compound (or more generally an encapsulation compound, which can also be a laminate, for example) in order to achieve robust electrical insulation realized by molding. Studies have shown that the described surface roughening of at least one connecting surface of the encapsulation compound with the functional structure to be applied (in particular a TIM layer) significantly prevents unwanted delamination of the applied structure from the encapsulation compound.

An embodiment of the invention therefore advantageously combines the integration of molded packaging and advanced insulating performance after a downstream process. Embodiments may improve the adhesion between an encapsulation compound, such as a molding compound (in the molded package scenario), and insulating material, thereby overcoming traditional problems with delamination.

Those skilled in the art understand that an intrinsic mold roughness produced by conventional manufacturing of a package without performing a selective, specific, and intentional roughening process can range between 0.4 μm and 0.8 μm (spatially non-specific). Such an intrinsic mold surface roughness due to manufacturability restrictions (in particular with regard to mold compound sticking and cleaning frequency) is less than 1 μm. However, a package roughness of less than 1 µm results in a package that tends to delaminate a functional structure, such as a TIM layer, from an encapsulant.

In contrast, one embodiment provides selective and spatially defined package roughening that is limited to an interface of the encapsulant with a functional structure. In particular, a molded package is provided with selective surface roughening which has been found to provide better adhesion between encapsulant and functional structure (e.g. TIM material) formed thereon. This can have the advantage of providing the possibility of parallel processing and therefore lower manufacturing costs. Furthermore, such an architecture allows the omission of a separate roughening step when roughening is integrated into the encapsulation procedure by a roughening forming mold of an encapsulation tool. Furthermore, with such an architecture, there is no undesired effect of carbonization of a transfer molding compound.

1 12 illustrates a cross-sectional view of an electronic component 100 implemented as a transistor outline (TO) electronic component according to an embodiment of the invention.

The electronic component 100, which can also be referred to as a semiconductor package, comprises an electrically conductive chip carrier 102, which is embodied here as a leadframe. In addition, an electronic chip 104, which is embodied here as a power semiconductor chip, is mounted on the carrier 102, for example via an adhesive 140. One or more die pads of the electronic die 104 may be electrically coupled to the die carrier 102 via one or more bond wires 150 . An encapsulation compound 106, for example a molding compound, which may be composed of an epoxy-based material with silica-based filler particles, encapsulates a portion of the carrier 102. The material of the encapsulation compound 106 may have a thermal conductivity of approximately 1 W m ^-1 K ^-1 and has electrically insulating properties. However, another portion of the carrier 102 extends beyond the encapsulant 106 and is therefore exposed to an environment. In addition, the electronic chip 104 is encapsulated by the encapsulation compound 106 .

Additionally, an electrically insulating and thermally conductive interface structure is provided, which may be referred to as a functional structure 108, covering an exposed surface portion of the carrier 102 and a bonded surface portion of the encapsulation compound 106 to electrically decouple the covered surface of the carrier 102 from an environment.

A through hole 114 (see FIG 2 ) be formed such that it extends through the encapsulation compound 106 and the functional structure 108, so that a fastening element 116 (see 12 ), here a screw, can be passed through the through hole 114 and into the heat dissipation body 112 to attach the heat dissipation body 112 to the rest of the electronic component 100 . Consequently, the heat dissipation body 112 is connected to the functional structure 108 with direct contact. As a result, heat generated by the electronic chip 104 during the operation of the electronic component 100 can be dissipated via the carrier 102 and the encapsulation compound 106 and via the functional structure 108 to the heat dissipation body 112 and from there to the environment. In the embodiment shown, the heat dissipation body 112 is an integral body of high thermal conductivity that includes a base structure 182 that is in direct contact with the functional structure 108 and includes a plurality of cold fingers or fins 184 that extend from the base structure 182 extend from.

The functional structure 108 can have a vertical thickness of approximately 300 μm (for example it can have a thickness in a range between 50 μm and 1000 μm, in particular in a range between 100 μm and 500 μm) and can be composed of a silicon-based matrix , which is filled with aluminum oxide-based filler particles. It can have a thermal conductivity of approximately 5 W m ^-1 K ^-1 and electrically insulating properties. The functional structure 108 fulfills different functions at the same time: On the one hand, it covers an exposed surface section of the carrier 102 and adjacent sections of the encapsulation compound 106 and therefore serves as electrical insulation that prevents an electric current from flowing between an interior and an exterior of the encapsulation compound 106 flows. On the other hand, the functional structure 108 is thermally conductive and allows thermal energy to be conducted from an interior of the encapsulation compound 106, ie from the electronic chip 104 to an environment. Therefore, the functional structure 108 also has a cooling function.

A discontinuity 120 embodied as an annular groove in the encapsulation compound 106 is formed in the surface portion of the encapsulation compound 106 that is covered by the functional structure 108 . The discontinuity 120 may be formed during the encapsulation process by appropriate shaping of an encapsulation tool (such as a mold tool) or alternatively by laser machining. As a particular 180 in 1 As can be seen, a portion of the bonded surface portion of encapsulant 106 surrounding discontinuity 120 is roughened to thereby form a spatially selective roughened surface 130 of encapsulant 106 . Thus, the discontinuity 120 is formed as a macroscopic ring-shaped depression in the surface portion of the encapsulation compound 106 that is covered by the functional structure 108 . The roughened surface 130 forms a microscopic, ring-shaped vicinity of the discontinuity 120. Thus, manufacturing the electronic component 100 includes FIG 1 described method includes forming the discontinuity 120, embodied here as an annular depression, in the encapsulant 106 adjacent to and surrounded by the roughened surface 130 of the encapsulant 106. More specifically, two annular surface portions of encapsulant 106 surrounding an interior and an exterior of annular discontinuity 120 are selectively roughened to thereby form roughened surface 130, while other surface portions of encapsulant 106 are not roughened. More specifically, the surface roughness of the roughened surface 130 of the encapsulant 106 surrounding the discontinuity 120 is higher (e.g., Ra = 2.5 µm) than the surface roughness (e.g., Ra = 0.4 µm) of the smoother, remaining surface of the encapsulant 106 As will be described in more detail below, the surface roughening of the encapsulant 106 around the discontinuity 120 to form the roughened surface 130 may be produced by a corresponding localized roughening of an interior surface portion of a mold tool through which the encapsulant 106 is formed. This inner surface portion of the mold tool may define the roughened surface 130 of the encapsulation compound 106 during molding and therefore imprint an inverse topology of the roughened, inner surface portion of the mold tool into the encapsulation compound 130 than the roughened surface 130 into the thereby roughened surface 130 of the encapsulation compound 106 . As a result of this manufacturing process, the roughened surface 130 has a uniform or uniform and substantially periodic roughness profile (see FIG 11 ) on.

In view of the manufacturing process described, the roughened surface 130 of the encapsulation compound 106 has a locally limited higher roughness than another roughness in a remaining surface of the encapsulation compound 130 . This combines two advantages: On the one hand, the roughened surface 130 of the encapsulation compound 106 increases adhesion to the functional structure 108 by increasing the effective connection area between the encapsulation compound 106 and the functional structure 108. On the other hand, by spatially confining the roughened surface 130 to the two rings on the inner and outer Excessive roughening of the encapsulant 106 from an encapsulation tool can be prevented from being complicated by removal of the electronic component 100 from an encapsulation tool in view of excessive adhesion between the encapsulant 106 and the encapsulation tool. If the latter adhesion becomes too pronounced, the removal of the electronic component 100 from the encapsulation tool may require additional measures such as auxiliary tools and/or auxiliary treatment. Additionally, while significant or even total surface roughening of encapsulant 106 is possible in accordance with certain embodiments of the invention, selective, localized roughening of a small portion of the surface area of encapsulant 106 is preferred (e.g., no more than 10% of the surface area of encapsulant 106 ). Locally roughening simultaneously with the formation of the encapsulant 106 is highly advantageous since it eliminates the need for a separate roughening procedure.

In order to further improve the adhesion of the functional structure 108, it is optionally also possible for at least part of the surface section of the carrier 102, which is covered by the encapsulation compound 106, to also be roughened.

In addition, to further significantly improve the adhesion between the functional structure 108 and the encapsulation compound 106, the roughened surface 130 of the encapsulation compound 106 can optionally be treated by a plasma after the roughening procedure. If if desired, cleaning of the roughened surface 130 can be carried out in addition to or as an alternative to plasma activation before the roughened surface 130 is covered by the functional structure 108 . This further suppresses an undesired delamination of the functional structure 108 from the encapsulation compound 106.

2 12 illustrates a three-dimensional front view 200 and a three-dimensional rear view 250 of the electronic component 100 according to FIG 1 . How out 2 As can be seen, a through hole 114 can be provided, which extends through the encapsulation compound 106 and the functional structure 108, so that a fastening element (see reference number 116 in 12 ), for example a screw, can be passed through the through hole 114 to fix the electronic component 100 to the heat dissipation body 112 .

3 illustrates part of the encapsulation tool 300, designed here as an upper mold tool, whereas a lower mold tool of the encapsulation tool 300 in 3 is not shown. 3 10 further shows a portion of an electronic component 100 prior to attachment of a thermal interface structure or any other functional structure 108 according to an embodiment of the invention 3 Roughening is performed during encapsulation using the encapsulation tool 300 with an inverse roughened surface 302 . Correspondingly, the discontinuity 120 is also implemented with an inverse discontinuity 304 by and during the encapsulation with the encapsulation tool 300 . Thus, according to the manufacturing procedure 3 no separate manufacturing procedures are necessary either for forming the discontinuity 120 or for forming the localized, selectively roughened surface 130 in the encapsulant 106. In contrast, the noted features (see reference numerals 120, 130) are formed simultaneously with molding. It's over as well 3 it can be seen that all other surface areas (other than the roughened surface 130) of the encapsulant 106 are smooth, or more precisely, smoother than the roughened surface 130. The package roughness on the roughened surface 130 is controlled by appropriate design of the mold - or encapsulation tool 300 defined. The roughened surface 130 of the encapsulation compound 106 is thus already finished after molding. Thus shows 3 a selective surface roughening of a molded packing for better adhesion. Optionally, an in-line plasma process may be performed to further activate the roughened surface 130 to further promote adhesion of the functional structure 108 thereto. In this plasma process, either the roughened surface 130 of the encapsulation compound 106 or the entire exposed surface of the encapsulation compound 106 can be surface-activated selectively. The plasma or plasma batch process can be integrated into a compression molding machine to activate the roughened surface 130 (e.g. to remove impurities) for further improved adhesion of the here electrically insulating functional structure 108 . A delamination-free concept is realized by this measure.

4 FIG. 4 illustrates detail 400 of the surface portion of encapsulant 106 with roughened surface 130 surrounding discontinuity 120 and FIG 3 is made. The roughened surface 130 provides adequate adhesion, while the remaining, smoother surface region of the encapsulant 160 ensures that the molded electronic component 100 can be easily removed from the encapsulation tool 300 after the encapsulant 106 is formed.

5 and 6 illustrate a process for bonding a thermal interface material (TIM) as a functional structure 108 to a remainder of an electronic component 100, according to an embodiment of the invention.

As 5 can be seen, an insulating material, which later forms the functional structure 108, can be applied by an application device 500. Subsequently, the insulating material is shaped and connected to exposed surface portions of the chip carrier 102 and the encapsulation compound 106 (particularly including its roughened surface 130) by compression molding, ie using a compression molding tool 600.

7 12 illustrates a laser device 700 and a portion of an electronic component 100 prior to attachment of a functional structure 108 according to an embodiment of the invention 7 For example, roughening a surface portion of the encapsulant 106 to thereby form the roughened surface 130 after encapsulation can be performed by subsequent localized laser processing. As an alternative to laser machining, it is also possible to create the discontinuity 120 and/or the roughened surface 130 by mechanical drilling and/or gouging.

8th illustrates a detail 800 of a surface portion of an encapsulant 106 having a roughened surface 130, the one according to 7 manufactured discontinuity 120 surrounds. 8th differs from 4 essentially relating to the shape of the projections that define the roughened surface 130, which is a consequence of the different manufacturing processes (forming of the roughened surface 130 by appropriate shaping of an encapsulation tool 300 according to 3 as compared to forming the roughened surface 130 by laser processing according to FIG 7 ), see below 10 and 11 .

8A Figure 8 illustrates a detail 850 of a surface portion of an encapsulant 106 having a roughened surface 130 surrounding a discontinuity 120 and at the bottom surface of the discontinuity 120 shown in FIG 3 or according to 7 can be made. 8A differs from 3 and 7 in that according to 8A the roughened surface 130 is formed not only around the discontinuity 120 but also within the discontinuity 120 . More specifically, a portion of the roughened surface 130 is formed on the bottom surface of the discontinuity 120 . Alternatively, it is also possible for the roughened surface 130 to be formed only within the discontinuity 120 and not around the discontinuity 120 .

9 , 10 and 11 show characteristics of surface topologies according to different manufacturing procedures.

9 shows a relatively smooth surface 930 of an encapsulation compound 106, as is produced with a molding tool without a specifically roughened inner surface. The resulting surface topology shows small protrusions ("matt finish"). Thus shows 9 a uniform or uniform roughness profile intrinsically produced by molding with a very shallow depth (Ra significantly below 1 µm, typically between 0.4 µm and 0.8 µm) due to manufacturability effects (mold separation and cleaning frequency).

10 FIG. 13 shows a selectively roughened surface 130 of the encapsulant 106, the roughened surface 130 being formed by laser machining. Like a comparison of 10 With 9 As can be seen, the protrusions of the roughened surface 130 are significantly deeper than the smaller protrusions of the relatively smooth surface 930. The topology of FIG 10 relates to roughening by laser furrows. Different to 9 indicates 10 an uneven roughness profile. For example, the roughness shown may range between 5 µm and 20 µm.

11 13 shows a selectively roughened surface 130 of the encapsulation compound 106, the roughened surface 130 being formed by correspondingly roughening an inner surface of an encapsulation tool 300. FIG. Like a comparison of 11 With 9 As can be seen, the protrusions of the roughened surface 130 are significantly deeper than the much smaller protrusions of the relatively smooth surface 930. As compared to FIG 11 With 10 As can be seen, the protrusions of the roughened surface 130 are shown in FIG 11 uniform and substantially periodic, whereas the protrusions of the roughened surface 130 according to 10 show an unordered, random distribution. The topology according to 11 relates to mold tool roughening. Thus concerned 11 a selective pack roughening. The topology according to 11 shows a uniform or uniform roughness profile with a deeper roughness (Ra can range between 2 µm and 4 µm) than according to FIG 9 . Advantageously, the mentioned roughness values in the selectively roughened area do not pose any problems for the ejection of a preform of the packing from the mold tool.

12 12 illustrates a cross-sectional view of an electronic component 100 that includes a fastener 116, embodied here as a screw, for attaching the package and the heat dissipation body 112. FIG.

13 12 illustrates a cross-sectional view of an electronic component 100. The electronic component 130 of FIG 13 includes a clip 118 (rather than a screw) configured to connect the electronic component 100 to the heat dissipation body 112 .

14 12 illustrates a cross-sectional view of an electronic component 100 embodied as a light emitting diode (LED) package in the form of functional structure 108 that provides optical transmission capability.

The electronic chip 104, which is designed here as an LED, is mounted on a chip carrier 102, which can be designed as a leadframe. The upper main surface of the electronic chip 104 is electrically contact-connected to the chip carrier 102 via one or more bonding wires 150 . A silicone reflector is designed as a preformed body and in 14 shown as the encapsulant 106 . The functional structure 108 is embodied here as a further molding compound, which is formed by compression molding, and can be an optically transparent material, such as silicone. As 14 can be seen, side walls and a central wall section of the encapsulation compound 106 are designed as locally roughened surfaces 130, so that adhesion between the encapsulation compound 106 on the one hand and the functional structure 108 on the other hand is improved. A lens body 1510 is also made of an optically transparent material and can be configured as a preformed silicone lens.

According to 14 For example, the encapsulant 106 (which may be referred to as a first encapsulant) may be formed by transfer molding, whereas the functional structure 108 (which may be referred to as a second encapsulant) may be formed by compression molding.

15 12 illustrates a cross-sectional view of an electronic component 100 embodied as a sensor package with a magnetic molded structure in the form of functional structure 108 that provides a magnetic field generation capability.

According to 15 an electronic chip (not shown) is encapsulated in the encapsulant 106 in an interior of the package. A stamped grid, which in the embodiment shown has two electrical contacts, serves as the chip carrier 102. The sensor package shown requires a permanent magnetic field to function properly. In the embodiment shown, this is achieved by a permanent magnetic molding compound in the form of functional structure 108 . In order to promote adhesion between the encapsulation compound 106 on the one hand and the functional structure 108 on the other hand, a surface section of the encapsulation compound 106 can be provided with a roughened surface (in 15 Not shown).

It should be noted that the term "comprising" does not exclude other elements or features, and that "a" or "an" and their declensions do not exclude a plural. Elements that are described in connection with different embodiments can also be combined. It should also be noted that any reference signs should not be construed as limiting the scope of the claims. Furthermore, the scope of the present application should not be limited to the particular embodiments of the process, machine, manner of manufacture, composition of matter, means, method, 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.

Claims (26)

Electronic component (100), the electronic component (100) comprising: • an electrically conductive carrier (102); • an electronic chip (104) on the carrier (102); • an encapsulant (106) encapsulating at least a portion of at least one of the carrier (102) and the electronic chip (104); • a functional structure (108) covering a surface section of the encapsulation compound (106); • wherein at least part of the covered surface portion of the encapsulation compound (106) is spatially selectively roughened, • wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic chip (104) is exposed from the encapsulant (106) or wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic Chip (104) is in direct contact with at least part of the functional structure (108), • wherein the electronic component (100) further comprises a discontinuity (120) formed in the surface portion of the encapsulation compound (106) covered by the functional structure (108), at least a portion of the selectively roughened surface (130). the discontinuity (120) is adjacent. Electronic component (100) after claim 1 , wherein the roughened surface (130) of the encapsulation compound (106) has a uniform roughness profile. Electronic component (100) after claim 1 or 2 , wherein the roughened surface (130) of the encapsulation compound (106) has a roughness of at least 1 micron. Electronic component (100) according to any one of Claims 1 until 3 , wherein the roughened surface (130) of the encapsulation compound (106) has a roughness in a range between 1 micron and 10 microns. Electronic component (100) according to any one of Claims 1 until 4 , wherein the roughened surface (130) of the encapsulation compound (106) has a roughness in a range between 2 microns and 4 microns. Electronic component (100) according to any one of Claims 1 until 5 wherein at least a portion of the selectively roughened surface (130) is formed within the discontinuity (120). Electronic component (100) according to any one of Claims 1 until 6 , wherein the discontinuity (120) has a greater roughness than the selectively roughened surface (130). Electronic component (100) according to any one of Claims 1 until 7 wherein the selectively roughened surface (130) adjacent the discontinuity (120) has a greater roughness than the covered surface portion of the encapsulant (106) farther from the discontinuity (120). Electronic component (100) according to any one of Claims 1 until 8th , wherein the discontinuity (120) is formed as an annular depression in the surface portion of the encapsulation compound (106) that is covered by the functional structure (108). Electronic component (100) according to any one of Claims 1 until 9 , wherein the roughened surface (130) of the encapsulation compound (106) has a locally limited higher roughness than another lower roughness in a remaining surface of the encapsulation compound (106). Electronic component (100) according to any one of Claims 1 until 10 , wherein the selectively roughened surface (130) of the encapsulation compound (106) covered by the functional structure (108) has a greater roughness than the surface portion of the encapsulation compound (106) that is not covered by the functional structure (108). Electronic component (100) according to any one of Claims 1 until 11 , wherein the at least part of the surface of the carrier (102) opposite to the electronic chip (104), which is exposed from the encapsulation compound (106) or has direct contact with at least part of the functional structure (108), and the covered surface section of the encapsulant (106) are on the same level. Electronic component (100) according to any one of Claims 1 until 12 , wherein the at least part of the surface of the carrier (102) opposite to the electronic chip (104), which is exposed from the encapsulation compound (106) or has direct contact with at least part of the functional structure (108), and the covered surface section of the encapsulation compound (106) are arranged adjacent to one another and form a common surface. Electronic component (100) after claim 12 or 13 , wherein from the at least part of the surface of the carrier (102) opposite to the electronic chip (104), which is exposed from the encapsulation compound (106) or has direct contact with at least part of the functional structure (108), and the covered Surface portion of the encapsulation compound (106) only the covered surface portion of the encapsulation compound (106) is selectively roughened. Electronic component (100) according to any one of Claims 1 until 13 , wherein at least a portion of at least a portion of the surface of the carrier (102) opposite the electronic chip (104) that is exposed from the encapsulation compound (106) or that is in direct contact with at least a portion of the functional structure (108) is roughened is. Electronic component (100) according to any one of Claims 1 until 15 , wherein the functional structure (108) is an electrically insulating and thermally conductive interface structure. Electronic component (100) after Claim 16 wherein the electronic component (100) for dissipating heat generated by the electronic chip (104) during operation of the electronic component (100) further comprises a heat dissipation body (112) attached or to be attached to the interface structure (108). Electronic component (100) according to any one of Claims 1 until 17 wherein the electronic chip (104) is configured as at least one of the group consisting of: • a power semiconductor chip (104); and • an electronic chip (104) with vertical current flow. Electronic component (100) according to any one of Claims 1 until 18 , wherein the functional structure (108) is an optically transparent structure. Electronic component (100) according to any one of Claims 1 until 19 , wherein the functional structure (108) is a magnetic structure. Electronic component (100) according to any one of Claims 1 until 20 , wherein the functional structure (108) is designed to provide mechanical decoupling of a microelectromechanical structure. Electronic component (100) according to any one of Claims 1 until 21 , wherein the encapsulation compound (106) comprises a first molding compound and the functional structure (108) comprises a second molding compound. A method of manufacturing an electronic component (100), the method comprising: • mounting an electronic chip (104) to an electrically conductive carrier (102); • encapsulating at least a portion of at least one of the carrier (102) and the electronic chip (104) by an encapsulant (106); • forming a discontinuity (120) in a surface portion of the encapsulant (106); • spatially selectively roughening a surface portion of the encapsulant (106) to thereby form a spatially selectively roughened surface (130), at least a portion of the selectively roughened surface (130) being adjacent to the discontinuity (120); • Covering at least part of the roughened surface (130) of the encapsulation compound (106) with a functional structure (108), • wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic chip (104) is exposed from the encapsulant (106) or wherein at least a portion of a surface of the carrier (102) that is opposite to the electronic Chip (104) is in direct contact with at least part of the functional structure (108), • wherein the discontinuity (120) is formed in the surface portion of the encapsulation compound (106) that is covered by the functional structure (108). procedure after Claim 23 , wherein after the spatially selective roughening, the method comprises at least one of the group consisting of plasma treating and cleaning the roughened surface (130) of the encapsulant (106). procedure after Claim 23 or 24 wherein the roughening during encapsulation is performed using an encapsulation tool (300) having an inverse roughened surface (302) with respect to the roughened surface (130). procedure after Claim 25 , wherein the encapsulation tool (300) is a mold tool, and wherein the roughening is carried out during the molding of the encapsulation compound in the mold tool.

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