EP3271942A1

EP3271942A1 - Electronics module comprising alpha-radiation protection for a transmission control unit and transmission control unit

Info

Publication number: EP3271942A1
Application number: EP16700986.9A
Authority: EP
Inventors: Uwe Liskow
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-03-20
Filing date: 2016-01-19
Publication date: 2018-01-24
Also published as: WO2016150582A1; CN107637186A; DE102015205051A1; TW201707183A

Abstract

Disclosed is an electronics module (12) for a transmission control unit (10) and a corresponding transmission control unit (10). The electronics module (12) comprises a printed circuit board element (14) comprising an electronic circuit (18), which is arranged on a mounting surface (16) of the printed circuit board element (14) and has at least one unhoused semi-conductor element (20) which is arranged with a contact surface (22) on the mounting surface (16). The electronic circuit (18) is fully covered by a protective compound (26). The electronics module (12) is characterised in particular in that on a surface (28) of the semi-conductor element (20), which surface is arranged opposite the contact surface (22), a protective layer (30) is arranged for protecting the semi-conductor element (20) from ionising radiation, wherein the protective layer (30) has a surface emission rate of alpha radiation which is lower than a surface emission rate of alpha radiation of the protective compound (26). In this way, the semi-conductor element (20) can be protected from radiation-induced damage.

Description

description

Electronic module with alpha radiation protection for a transmission control unit and transmission control unit

Field of the invention

The invention relates to an electronic module for a transmission control unit of a motor vehicle. In particular, the invention relates to an electronic module with a protected against ionizing radiation semiconductor device and a transmission control unit with such an electronic module.

State of the art

For controlling transmissions, in particular automatic transmissions, in a motor vehicle, electronic transmission control units or

Transmission control modules used either inside a

Gear housing are arranged as integrated transmission control units or mounted from the outside as add-on modules to the transmission housing.

Integrated transmission control units generally have an electronic module with an electronic circuit (so-called transmission control unit, TCU), at least one sensor, at least one plug connection for connection to a vehicle wiring harness and electrical interfaces for actuating actuators.

The electronic circuits of the electronic modules can have various components, in particular capacitors, memory,

Power amplifiers, resistors and / or semiconductor chips or

Semiconductor devices. Due in part to space limitations, so-called "bare-die components", ie unhoused silicon components or unhoused semiconductor components, are used for semiconductor components. In order to protect the electronic circuits and / or the electronic modules of the integrated transmission control units, for example, against these at least partially circulating transmission fluid, the electronic circuits and / or the electronic modules are protected by a protective compound or molding compound.

Such a transmission control module is disclosed in DE 10 2011 088 969 AI.

Disclosure of the Invention Advantages of the Invention

Embodiments of the present invention can advantageously make it possible to provide a reliable, robust and / or cost-producible electronic module for a transmission control unit of a motor vehicle and a transmission control unit with such an electronic module.

According to a first aspect of the invention, an electronic module for a transmission control unit is proposed. The electronics module has a

Printed circuit board element with an electronic circuit, wherein the electronic circuit is arranged on a mounting surface of the printed circuit board element and has at least one ungehäustes semiconductor device, which is arranged with a contact surface on the mounting surface. The electronic circuit is completely covered by a protective compound. The electronic module according to the invention is characterized in particular in that on one of the contact surface oppositely arranged surface of the

Semiconductor device, a protective layer for protecting the

Semiconductor device is disposed against ionizing radiation, wherein the protective layer has a surface emission rate of alpha radiation, which is less than a surface emission rate of alpha radiation of the protective composition. The protective layer can cover the surface of the semiconductor device over the entire surface or only partially.

The protective compound may be provided for protecting the electronic circuit against transmission fluid. In the protective composition, however, unstable nuclides and / or unstable isotopes, such as ²³⁸ U and / or ²³⁴ U, may be included, which can decay in a decay series under emission of ionizing radiation into stable isotopes. In particular, alpha particles or

Alpha radiation, ie helium nuclei, are emitted. Hits an alpha particle The unhoused semiconductor component may be due to deposition of the energy of the alpha particle in the semiconductor component, for example, to a local, hardware damage, such as for separating a conductor pattern of the semiconductor device (so-called single event effects). Also, about capacitive storage bits in the semiconductor device can be set from 0 to 1 or vice versa. Such software damage is often referred to as a radiation-induced "soft error".

A way of avoiding the aforementioned radiation-induced

Damage to the semiconductor device can be about a use of a

High purity protective composition, i. a protective compound with little unstable and alpha particles emitting isotopes per volume or

Mass unit of the protective mass. As a measure of a purity of the protective composition, the surface emission rate of alpha particles can be used, which in units of counts or decay per unit time and area (eg counts / (h cm ² ) or l / (h cm ² ) or counts per hora / cm ² or cph / cm ² ). However, such protective compounds can be associated with considerable material costs. Furthermore, the electronic circuit usually also has electronic components which, for example, are insensitive to radiation due to sufficiently large conductor path structures of the component and / or which have their own housing, as may be the case, for example, in so-called "surface mounted devices" or SMD components. Therefore, such components do not necessarily have to be protected against costly radiation by a costly protective compound.

For example, for about 90 nm large interconnect structures, a purity or quality of the protective composition of about 0.01 cts / (h cm ² ) may be sufficient. By contrast, it is possible for a circuit pattern of around 40 nm to have a thickness of less than 0.01 cts / (h cm ² ) (so-called low-alpha protection mass) and even around 0.001 cts / (h cm ² ).

(so-called ultra-low-alpha or super-low-alpha protection mass) are assumed. The cost of such high purity protective compositions, if available at all, may sometimes be, e.g. be twice as high. Furthermore, such high-purity protective compounds are usually not in combination with others

Properties or other requirements placed on the protective composition available, such as a specific coefficient of thermal expansion (CTE) and / or a required

Resistance to eg transmission oil. According to the invention, a direct mechanical contact of the protective compound with the surface of the semiconductor component is avoided by the protective layer. Furthermore, alpha particles emitted by unstable isotopes of the protective mass are absorbed in the protective layer, causing a radiation-induced

Damage to the semiconductor device can be avoided. By shielding the invention or the protection of the unhoused

Semiconductor device using the protective layer, which has a smaller

Area emission rate of alpha particles as the protective mass, so targeted and locally limited comprehensive protection of the semiconductor device can be provided without, for example, the entire electronic circuit would need to be protected with a costly high-purity protective ground. Overall, therefore, a reliable working and robust

Electronic module can be provided and production and material costs of the electronic module can be saved or kept low by the local limited use of high purity protective compound.

Ideas for embodiments of the present invention may be considered, inter alia, as being based on the thoughts and findings described below. Increasing miniaturization of the electronic circuit and / or the components of the electronic circuit may result in finer structures in the silicon of the components or in the unhoused semiconductor component, which may have, for example, a microcontroller, a logic module and / or a current regulator ASIC. At present, microcontroller silicon wafers or unhoused semiconductor components or chips have one

Circuit trace structure of about 90 nm. New generations of these devices may have structures in a range of about 40 nm. The detached from the wafer and in the form of unhoused semiconductor devices isolated circuits are often called Bare- Dies. These are e.g. connected to pin rows by bonding wires and in a mold tool with

Duroplast ummoldet or surrounded. The result is so-called "integrated circuits" (ICs), ie, packaged semiconductor devices, such as SMD devices. Particularly for the fabrication of small electronic circuits or for the manufacture of compact electronic modules, the bare dies are also provided without housing on the circuit board element, such as a printed circuit board circuit board "

(PCB), a high-density interconnect printed circuit board (HDI-PCB), a "low-temperature cofired ceramics" (LTCC) substrate or a "high-temperature cofired ceramics" (HTCC) substrate glued, bonded and / or soldered , These components can be protected for use in a transmission control unit with the protective compound and optionally with a lid against the environment such as air, oil and / or fuel. The complete electronic circuit and / or the electronic module as a transmission control unit or

Transmission control unit may e.g. ummoldet or potted with Duroplast as a protective mass. In a new generation of integrated

Transmission control units, the Molden be replaced by dispensing or spraying, for example, an epoxy resin-based protective compound. In any case, the thermosets used as a protective composition and / or

epoxy resin-based materials contain unstable mineral fillers that can emit alpha radiation. Alpha radiation arises spontaneously in a statistical process. In a typical electronic module material, alpha particles may have an average range of e.g. around 1 mm. However, they can be stopped by thin layers such as 80 μηη thick paper and / or thin plastics and / or metals.

If an alpha particle strikes a semiconductor component with a conductor track structure of approximately 40 nm, as described above, hardware-related and / or software-related damage to the semiconductor component may occur. Such damage can in turn have a malfunction of the electronic module result.

By the inventive shielding of the unhoused

Semiconductor device through the protective layer can be kept low in an advantageous manner, an amount used of a costly, high-purity protective composition. The electronic circuit can thus be comprehensively protected with a protective compound having a surface emission rate of, for example, greater than or equal to 0.1 cts / (h cm ² ), which can be associated with considerable cost savings. According to one embodiment of the invention, the protective layer covers one

Central region of the surface of the semiconductor device, wherein the

Central region is bounded by a contacted with at least one exposed bonding wire edge region of the surface. In other words, the protective layer is disposed in a region of the surface or covers an area which, within the outer bonding wire as

Verbindungsbond may lie to the circuit board element, so that the

Protective layer can not be in mechanical contact with the bonding wire. This may cause a risk of air bubbles and / or lifting the Bonding wire can be avoided for example by the so-called Kirkendall effect. Overall, such a robust and reliable electronic module can be provided. In contrast, if the semiconductor device, for example by means of solder balls on the

Contact surface electrically connected to the circuit board element, the protective layer over the entire surface can cover the surface of the semiconductor device. Even in this case, however, a covering of a flank of the

Semiconductor device with the protective layer can be avoided, for.

To avoid air pockets between the contact surface and the mounting surface and / or a failure of the electronic module caused by solder corrosion.

According to one embodiment of the invention, the protective layer has a thickness of at least 20 μm and at most 2.5 mm. The thickness of the protective layer may be, for example, about 1 mm. The thickness of the protective layer should have at least a value of mean range of alpha particles in the material of the protective layer, so that alpha particles can be reliably absorbed in the protective layer. According to one embodiment of the invention, the surface emission rate of

Alpha radiation of the protective layer is less than or equal to 0.01 cph / cm ² . As a result, damage to the semiconductor device due to decomposition of unstable isotopes contained in the material of the protective layer can be avoided. According to one embodiment of the invention, the protective layer is light-curing, for example UV-light-curing, and / or thermosetting, for example by infrared radiation.

As a result, the protective layer can be precrosslinked and / or at least partially cured during manufacture of the electronic module quickly and reliably, so that mixing of the protective compound with the material of the protective layer and direct mechanical contact of the protective compound with the

Surface of the semiconductor device can be avoided.

According to one embodiment of the invention, the protective layer comprises epoxy resin-based material, polyacrylate-based material, epoxy adhesive, acrylate adhesive, and / or acrylic adhesive. Such materials can

be advantageous in particular with a view to rapid curing, which can be about manufacturing costs saved. Also, bare-die adhesive, by means of which about the contact surface of the semiconductor device on the Mounting surface of the printed circuit board element can be fixed, as

Protective layer are applied to the surface of the semiconductor device. Such adhesives are often referred to as "Anisotropy Conductive Film (ACF)" or "Anisotropy Conductive Adhesive" (ACA) and can be characterized by a high purity with respect to alpha-emitting isotopes.

According to one embodiment of the invention, the electronic module further comprises a protective plate for protecting the semiconductor device against ionizing radiation, wherein the protective plate on the on the surface of the

Semiconductor component arranged protective layer is arranged. In other words, the protective layer for fixing the protective plate on the

Serve semiconductor device. The protective plate can advantageously provide comprehensive protection of the semiconductor component against ionizing radiation and / or further increase the protection.

According to one embodiment of the invention, the protective plate has a

Ceramic material, metal, a plastic, a duroplastbasiertes material, an epoxy resin-based material, polyacrylate-based material, epoxy adhesive, acrylate adhesive and / or acrylic adhesive on. The protective plate should be made of one

Material to be made, which has a high purity with respect to alpha emitting isotopes. The protective layer itself can be made relatively thin in this case and essentially serve for fixing the protective plate. For example, the protective sheet of the material of the protective layer can be prefabricated by molding and curing and fixed on the surface during manufacture of the electronic module.

As a result, a hardening time of the protective layer can be reduced or eliminated altogether, since mixing of the material of the protective layer and the protective compound by the protective plate can be avoided.

Another aspect of the invention relates to a transmission control unit. The

Transmission control unit has an electronic module, as described above and below, and a carrier plate. The printed circuit board element of the electronic module is arranged with a surface arranged opposite to the mounting surface on the carrier plate, wherein the

Transmission control unit is designed to be lapped by a transmission fluid. In other words, the transmission control unit may be an integrated transmission control unit or an integrated transmission control unit act, which can be installed within a transmission housing, for example in a motor vehicle.

According to one embodiment of the invention, the transmission control unit has a printed circuit board element annularly enclosing printed circuit board and / or a flex foil, wherein the circuit board element is electrically contacted with the printed circuit board and / or the flex foil.

Another aspect of the invention relates to a method for manufacturing an electronic module and / or a transmission control unit, as described above and below.

Brief description of the drawings

Embodiments of the invention will now be described with reference to the accompanying drawings, in which neither the drawings nor the description are to be construed as limiting the invention.

1 shows a transmission control unit 10 with an electronic module 12 according to an embodiment of the invention.

FIGS. 2A to 5 each show an electronic module according to embodiments of the invention.

The figures are only schematic and not to scale. Like reference numerals in the figures designate the same or equivalent

Characteristics.

Embodiments of the invention

The transmission control unit 10 has a carrier plate 11, on which a printed circuit board 13 with a recess or recess 15 is attached. In the recess 15, the electronic module 12 is arranged so that the circuit board 13, the electronic module 12 encloses substantially annular. The

Circuit board 13 may include, for example, a PCB board and / or a flex foil for electrically contacting components of the transmission control unit 10 and / or for electrically contacting the electronics module 12. On the circuit board 13 also electronic / electrical components 17 of the transmission control unit 10 are arranged. The components 17 can

For example, sensors, connectors, interfaces for driving actuators and / or other components, which may be electrically connected to the circuit board 13.

The circuit board 13 is arranged with one side 19 on the support plate 11 and fixed. For example, the printed circuit board 13 may be soldered, glued and / or welded to the carrier plate 11. In the area of the recess 15, the electronic module 12 lies with its entire surface 21 on the carrier plate 11.

The surface 21 of the electronic module 12 can be a surface 21 of a

Designate printed circuit board element 14 of the electronic module 12. The carrier plate 11 can in particular serve as a heat sink for the electronic module 12 and / or the transmission control unit 10 and serve to dissipate heat. Also, the electronic module 12 may be soldered, glued and / or welded with the surface 21 on the support plate 11.

The circuit board element 14 may include, for example, a PCB board element, an HDI board element, an LTCC substrate, and / or an HTCC substrate.

On an area 21 of the printed circuit board element 14 of the electronic module 12 opposite arranged mounting surface 16 of the printed circuit board element 14, an electronic circuit 18 is arranged. The electronic circuit 18 may e.g. an S MD device, a capacitor, a resistor and / or other electronic components. Furthermore, the electronic

Circuit 18 at least one ungehäustes semiconductor device 20 which is arranged and fixed with a contact surface 22 on the mounting surface 16, e.g. glued and / or soldered. The semiconductor device 20 is with

exposed bonding wires 24 electrically contacted with the printed circuit board element 14. The bonding wires 24 protrude from an outer surface of the

Semiconductor device 20 and / or from the mounting surface 16, which is why the bonding wires 24 can be regarded as "exposed." Alternatively or additionally, the semiconductor device 20 may, for example, as a "ball grid array" (BGA) device and / or "system in package" ( SiP) and the

Contact surface 22 may be electrically contacted via solder balls with the printed circuit board element 14 (eg wafer level package or flip chips). The electronic module 12 is further electrically contacted via bonding wires 23 with the circuit board 13 of the transmission control unit 10. However, the electronic module 12 may also be connected to the printed circuit board 13 with a suitable other electrical connection, for example via a flex foil. Furthermore, the

PCB element 14 of the electronic module 12 be part of the circuit board 13. In other words, the transmission control unit 10 may comprise a continuous, common printed circuit board 13, on which the components of the electronic module 12 may be arranged. The electronic circuit 18 is completely covered by a protective mass 26 for

Protection against external influences and / or transmission fluid covered. The bonding wires 23 and / or a region of the printed circuit board 13 adjacent to the electronic module 12 or the electronic components arranged in this region can also be completely covered by the protective compound 26. The

Protective material 26 can be, for example, a silicone gel, an epoxy resin-based

Material and / or a protective varnish included. The protective compound 26 may have a surface emission rate of alpha particles of greater than or equal to 0.01 cph / cm ² . The protective compound 26 can be applied by dispensing, spraying, die-casting, transfer molding and / or pouring, for example. Also, the protective compound 26 can be applied in a Dam & Fill process with two different viscous materials.

On a surface 28 of the semiconductor component 20 arranged opposite to the contact surface 20, a protective layer 30 is provided for protecting the surface

Semiconductor device 20 against ionizing radiation, in particular against

Alpha radiation or alpha particles, arranged. The ionizing radiation can be released or emitted by decomposition of unstable isotopes contained in the protective compound 26. In this case, the protective layer 30 covers a central region 32 of the surface 28, which is delimited by an edge region 34, in which the bonding wires 24 contact or are arranged on the semiconductor component 20. In other words, that covers

Protective layer 30 is not the bonding wires 24 and is only within the

outside bonding wires 24 applied to the surface 28, so that air pockets on the bonding wires 24 and / or about a failure of the

Electronic module 12 can be avoided by the Kirkendall effect.

The protective layer 30 or the material of the protective layer 30 has a

Area emission rate of alpha particles smaller than that Area emission rate of alpha particles of the protective mass 26 is. For example, the surface emission rate of the protective layer may be less than or equal to 0.01 cph / cm ² . The protective layer 30 may contain, for example, epoxy resin-based material, polyacrylate-based material, epoxy adhesive, acrylate adhesive and / or acrylic adhesive.

To be able to provide complete protection against alpha particles, should

Alpha particles are absorbed within the protective layer 30. A thickness of the protective layer 30 should therefore be at least in a range of mean free path of alpha particles in the material of the protective layer 30. The thickness of the protective layer 30 may be e.g. at least 20 μηη and not more than 2.5 mm. Typically, the thickness of the protective layer 30 may be about 1 mm.

FIGS. 2A to 2C show an electronic module 12 according to an embodiment of the invention. In particular, FIGS. 2A to 2C illustrate process steps for manufacturing the electronics module 12. Unless otherwise described, the electronics module 12 of FIGS. 2A to 2C may have the same elements and features as the electronics module 12 of FIG. 1.

In the central region 32 between the bonding wires 24 and the edge region 34, in which the bonding wires 24 contact the semiconductor device 20, the material of the protective layer 30 is applied to the surface 28 in flowable form with a suitable applicator 29, for example, sprayed and / or poured, as shown in Fig. 2A. The applicator 29 can be moved relative to the semiconductor device 20.

The protective layer 30 or the material protective layer 30 may be light-curing and / or thermosetting. After the application of the protective layer 30, it is treated with a suitable curing device 31, e.g. with UV light, with

Infrared radiation and / or at least partially cured in a heating furnace, as shown in Fig. 2B. Curing with UV light is z. B. in polyacrylate-based material as a protective layer 30 possible. Epoxy-based material as

On the other hand, protective layer 30 can be cured by heat,

for example in a heating oven. A curing time may e.g. around 1

Hour at 120 ° C for typical epoxy resins amount. Alternatively, fast-curing materials can be used as protective layer 30, such as epoxy, acrylate and / or acrylic adhesive with a heat lamp (Infrared radiation) can be cured as a curing device 31 between 120 and 200 ° C for example, about 5 to 50 seconds. As material for the

Protective layer 30 is also a bare-the-adhesive suitable, as he also for

Attaching the semiconductor device 20 may be used on the mounting surface 16. Advantageously, on the one hand, the contact surface 22 of the

Semiconductor device 20 are bonded with the bare die adhesive to the mounting surface 16 and on the other hand, the same bare die adhesive than

Protective layer 30 on the surface 28 of the semiconductor device 20th

be applied. Such bare-die adhesives are often referred to as "Anisotropy Conductive Film" (ACF) or "Anisotropy Conductive Adhesive" (ACA).

The material of the protective layer 30 should in any case be low-alpha or ultra-low-alpha material with a surface emission rate of less than or equal to 0.01 eph / cm ² .

A thermal expansion coefficient (CTE) of the protection layer 30 should be between a CTE of the semiconductor device 20 and a CTE of the CTE

Protective mass 26 are. Since the CTE of the protective ground 26 may already be adapted to other components of the electronic circuit 18, due to

Insensitivity to alpha rays does not necessarily require an extra

Protective layer, the CTE of the protective layer 30 can be optimized, e.g. with regard to adhesion of the protective layer 30 to the semiconductor device 20 or adhesion to the protective ground 26. If the protective layer 30 has poorer adhesion to the semiconductor device 20 than to the protection ground 26, the CTE of the protection layer 30 should be closer to the CTE of the semiconductor device 20, to minimize shearing forces and / or to maximize adhesion. When using one ACF or ACA as the protective layer, the associated CTE may already be optimally matched to the CTE of the semiconductor device 20.

After the at least partial curing of the protective layer 30, as shown in FIG. 2C, the protective compound 26 can be applied to the electronic module 12 or to the electronic circuit 18. The protective compound 26 can be applied by dispensing, spraying, die-casting, transfer molding and / or pouring, for example. Also, the protective compound 26 in a Dam &

Fill method with two different viscous materials are applied. 3 shows an electronic module 12 according to a further embodiment of the invention. Unless otherwise described, the electronic module 12 of FIG. 3 may have the same elements and features as the electronic modules 12 of FIGS. 1 to 2C.

In the embodiment shown in FIG. 3, the electronic module 12 is completely encapsulated with protective compound 26. The electronic module 12 is z: B. Duroplast material encapsulated as protective compound 26 under pressure, wherein the electronic module 12 is completely enclosed by the protective compound.

Via connecting wires 36, the electronic module 12 with further

Components of a transmission control unit 10 to be contacted. Also, the entire transmission control unit 10 may be potted in protective compound 26, as shown in FIG. The electronic module 12 shown in FIG. 3 can have all the components of the transmission control unit 10 or it can

Electronic module 12 of FIG. 3 denote a transmission control unit 10.

4 shows an electronic module 12 according to a further embodiment of the invention. Unless otherwise described, the electronic module 12 of FIG. 4 may have the same elements and features as the electronic modules 12 of the preceding figures.

The protective layer 30 of the embodiment shown in FIG. 4 has a small thickness of, for example, a few tens of μηη and acts as an adhesive layer, by means of which a protective plate 38 is fixed and / or fixed on the surface 28 of the semiconductor device 20 for protection against ionizing radiation. The protective layer 30 may include, for example, bare die adhesives. The protective plate 38 covers at least the central region 32 of the surface 28 of the

Semiconductor device 20 from.

In order to provide sufficient protection against ionizing radiation and in particular against alpha particles, the protective plate may have a thickness of about 20 μm to a few mm, typically 1-2 mm. The protective plate 38 may be a ceramic material, metal, a plastic, a duroplastic-based material, an epoxy resin-based material,

polyacrylate-based material, epoxy adhesive, acrylate adhesive and / or acrylic adhesive have. For example, the ceramic protection plate 38 may be similar to an LTCC Substrate, a low alpha (0.01 cts / (h cm ² )), an ultra-low alpha (0.001 cts / (h cm ² )) material, e.g. As thermoset material, and / or be made of printed circuit board material.

Preferably, the protective plate 38 and / or the protective layer 30 has a thermal expansion coefficient (CTE) in a direction parallel to a normal vector of the surface 28 and the mounting surface 16, which is approximately identical to a CTE of the protective compound 26, so that

thermomechanical stresses at an interface to the surface 28 of the semiconductor device 20 can be kept low.

5 shows an electronic module 12 according to a further embodiment of the invention. Unless otherwise described, the electronic module 12 of FIG. 5 may have the same elements and features as the electronic modules 12 of the preceding figures.

In the embodiment shown in FIG. 5, the semiconductor device 20 is embodied as a "ball grid array" (BGA) device and / or "system in package" (SiP) and the contact surface 22 is connected via solder balls 40 with the

Printed circuit board element 14 electrically contacted.

The protective layer 30 covers the entire surface 28 of the

Semiconductor device 20, i. it can reach up to an outer edge 42 of the

Semiconductor device 20 range. To avoid air bubbles and / or failure of the electronic module 12 by solder corrosion, the

However, protective layer 30 may not be disposed on flanks of the semiconductor device 20. A region between contact surface 22 and mounting surface can be encapsulated with protective compound 26, for example. Finally, it should be noted that terms such as 'having',

"Include", etc., and do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality, and reference signs in the claims are not intended to be limiting.

Claims

claims

An electronic module (12) for a transmission control unit (10), comprising:

a printed circuit board element (14) having an electronic circuit (18), wherein the electronic circuit (18) is mounted on a mounting surface (16) of the

Printed circuit board element (14) is arranged and at least one ungehäustes semiconductor device (20), which is arranged with a contact surface (22) on the mounting surface (16);

the electronic circuit (18) being completely covered by a protective compound (26),

characterized in that

a protective layer (30) for protecting the semiconductor device (20) against ionizing radiation is arranged on a surface (28) of the semiconductor component (20) arranged opposite the contact surface (22), the protective layer (30) having a surface emission rate of alpha radiation which is lower is an area emission rate of alpha radiation of the protective mass (26).

2. Electronic module (12) according to claim 1,

wherein the protective layer (30) covers a central region (32) of the surface (28) of the semiconductor device (20),

wherein the central region (32) is bounded by an edge region (34) of the surface (28) which is in contact with at least one exposed bonding wire (24).

3. electronic module (12) according to claim 1 or 2,

wherein the protective layer (30) has a thickness of at least 20 μm and at most 2.5 mm.

4. Electronic module (12) according to one of the preceding claims,

wherein the area emission rate of alpha radiation of the protective layer (30) is less than or equal to 0.01 cph / cm ² .

5. Electronic module (12) according to one of the preceding claims,

wherein the protective layer (30) is light-curing and / or thermosetting.

6. electronics module (12) according to one of the preceding claims,

wherein the protective layer (30) is epoxy resin-based material, polyacrylate-based material, epoxy adhesive, acrylate adhesive, and / or

Contains acrylic adhesive.

7. The electronic module (12) according to one of the preceding claims, further comprising:

a protective plate (38) for protecting the semiconductor device (20) against ionizing radiation,

wherein the protective plate (38) on the surface (28) of the

Semiconductor device (20) arranged protective layer (30) is arranged.

8. electronics module (12) according to claim 7,

the protective plate (38) being a ceramic material, metal, a plastic, a thermoset-based material, an epoxy resin-based material,

polyacrylate-based material, epoxy adhesive, acrylate adhesive and / or

Acrylic adhesive has.

9. Transmission control unit (10), comprising:

an electronic module (12) according to one of the preceding claims, and a carrier plate (11),

the printed circuit board element (14) of the electronic module (12) being arranged on the carrier plate (11) with a surface (21) arranged opposite the mounting surface (16),

wherein the transmission control unit (10) is adapted to a

Transmission fluid to be lapped.

10. Transmission control unit (10) according to claim 9,

wherein the transmission control unit (10) comprises a circuit board element (14) annularly enclosing printed circuit board (13) and / or a flex foil, wherein the circuit board element (14) is electrically contacted with the circuit board (13) and / or the flex foil.