WO2017089209A1 - Electrical device having a covering material - Google Patents

Abstract

The invention relates to an electrical device (10) comprising an electrical component (12) that is at least partially covered by a covering material (20) that comprises a cement material (22). Said covering material (20) also comprises thermal buffer particles (24) which are arranged in the cement material and comprise a particle material or consist of a particle material that has a higher thermal capacity than that of the cement of the cement material (22).

Description

 description

title

Electric device with a wrapping compound

The present invention relates to an electrical device with a

electrical component, which is at least partially enveloped by a Umhüllmasse and a method for producing such an electrical device.

State of the art

Increasing reliability and efficiency, as well as lowering the cost of power electronics modules and robust sensor systems, are of paramount importance today. The current wrapping materials (epoxy

Compounds, silicone compounds) are limited to a temperature range below 200 ° C. By exploiting the temperature range of up to 300 ° C or 350 ° C for wrapping materials, the operating range of modern power semiconductors (eg SiC) can be extended beyond 200 ° C, without the additional function of a wrapping material (eg protection from environmental influences, improved Thermal) must be waived.

From DE102013112267A1 is a semiconductor module with a a

Semiconductor device covering cladding compound of various

Cement species known. The enveloping composition in this case has an additive which has a high thermal conductivity.

DISCLOSURE OF THE INVENTION The present invention relates to an electrical device with an electrical component which has a cement compound

Enveloping compound is at least partially enveloped, wherein the enveloping mass further comprises heat buffer particles, which are arranged in the cement paste and a Have particulate material or consist of a particulate material having a higher heat capacity than the cement of the cement paste.

The present invention is further a method for producing an electrical device with an electrical component, which of a one

Cement mass comprising encasing material is at least partially enveloped, comprising the following steps:

 - Providing the cement paste;

 - Mixing of heat buffer particles in the cement paste, wherein the

 Heat buffer particles have a particulate material or consist of a particulate material having a higher heat capacity than the cement paste of the cement paste;

 - Applying the cement paste with the heat buffer particles having

 Enveloping mass on the electrical component such that the Umhüllmasse the electrical component at least partially envelops; and

 - Heat treatment of Umhüllmasse.

The subject of the present invention is also the use of a mass comprising a cement paste and heat buffer particles as encasing material for an electrical component of an electrical device, the heat buffer particles being arranged in the cement mass and having a particulate material or consisting of a particulate material having a higher heat capacity than the cement having the cement mass.

The electrical component may, for example, a semiconductor component, a sensor element, an inductance, a capacitance, a battery cell, a battery module or a

Circuitry be. Under an electrical component, however, in the context of the present invention, any active and passive component or

High performance device to be understood. The electrical device may in this case have a carrier substrate on which the electrical component is arranged.

Under a cement can be understood in the context of the present invention, an inorganic, metal-free, hydraulic binder. The cement hardens in this case hydraulically, ie it takes a chemical reaction with water instead of formation stable, insoluble compounds. Here, the cement may be formed at the beginning of the process or prior to hydration as finely ground powder, which reacts with water or addition of water with the formation of hydrates, solidifies and hardens. The hydrates can form needles and / or platelets, which interlock and thus lead to a high strength of the cement. In contrast, a phosphate cement does not harden hydraulically. An acid-base reaction takes place to form a salt gel, which later solidifies to a mostly amorphous mass. In the acid-base reaction, H + (hydrogen ions) are exchanged.

The cement may consist predominantly of calcium aluminates and form calcium aluminate hydrates during hydration. It is advantageous if the

Cement composition has alumina cement, in particular consists of alumina cement. Alumina cement (abbreviated CAC) is regulated in accordance with DIN EN 14647 European.

Alumina cement consists mainly of monocalcium aluminate (CaO * Al 2 O 3).

The alumina cement may, for example, have the following composition:

 AI203: greater than or equal to 67.8% by weight

 CaO: less than or equal to 31.0% by weight

 SiO 2: less than or equal to 0.8% by weight

 Fe203: less than or equal to 0.4% by weight

In the context of the present invention, heat-buffer particles can be understood as meaning a particulate additive. The heat buffer particles are in this case designed to withstand the requirements of the heat treatment and stable in operation. The heat buffer particles may be powdered before the step of mixing into the cement paste. The

However, heat buffer particles can also have a liquid fraction. Accordingly, the heat buffer particles may be in the form of a solution or dispersion or suspension, for example with a water content. The heat buffer particles can be mixed in a dry cement paste or cement powder mixture, ie, if necessary, before the addition of water is added. However, the heat buffer particles can also be mixed into the wet cement paste or cement powder mixture, ie if necessary, the addition of water was added. The heat buffer particles can have a Have particle diameter d50 in the range of greater than or equal to 1 μηη to less than or equal to 600 μηη.

In the context of the present invention, an encapsulation compound can be understood as any type of encapsulation (packaging). The Umhüllmasse can as

Cement composite be formed. That is, in other words, that the encapsulant may comprise a cement matrix with a filler as well as the heat buffer particles. The coating composition may have the following composition:

 Binder alumina cement: greater than or equal to 8% by weight to less than or equal to 47

% By weight (eg SECAR 71)

 Reagent Water: greater than or equal to 10 wt% to less than or equal to 28 wt%

 Heat buffer particles: greater than or equal to 1 wt% to less than or equal to 13 wt%

 Filler: greater than or equal to 25% by weight to less than or equal to 82% by weight

The filler may be selected from the group consisting of:

 - AI203: fine d50 about 1 μηη to roughly d50 about 150-200 μηη

 - Alpha-Si3N4: fine about 1 μηη to roughly 100 μηη

 - Hex. BN: fine about 15 μηη or up to about 250 μηη

 - SiC: fine about 10-50 μηη or up to about 600 μηη

 - AIN: fine about 1 μηη or up to about 100 μηη

The heat-treating step may in the context of the present invention comprise a hydration step and / or setting step and / or drying step and / or curing step. The heat treatment may comprise a tempering step in a tempering furnace. The heat treatment can be done in one

Temperature range greater than or equal to 40 ° C to the same or equal to 95 ° C.

Accordingly, it is possible according to the invention by the addition of

Wärmepufferpartikeln with a higher heat capacity or thermal capacity than that of the cement of the cement paste, the thermal properties of

To tailor Umhüllmasse depending on the requirements and in particular to significantly increase the total thermal capacity of Umhüllmasse. That is, with others Words that not the thermal conductivity of Umhüllmasse should be increased to deliver the heat from the electrical component as quickly as possible to the environment, but rather by increasing the heat capacity a high

Heat buffering and thus thermal overload capacity is achieved. The

Thermal conductivity of Umhüllmasse can thus in favor of the thermal

 Capacity can be made lower, depending on curing or load during operation, to achieve a specific optimum between the thermal conductivity and the heat capacity for the particular application and thus the

To trim or optimize the operating state. Accordingly, an electrical device can be provided which is particularly robust at high

 Power loss peaks during operation and provides protection of the electrical component against overheating.

It is also advantageous if the heat capacity of the particulate material at a temperature of RT-350 ° C in a range of greater than or equal to 900 J / kgK. The thermal capacity of alumina cement is 750-900 J / kgK. Through this

Measure, the total capacity of Umhüllmasse further increased and absorbed the amount of heat from the electrical component up to a maximum operating temperature of 350 ° C very efficiently.

It is also advantageous if the particulate material is selected from the group consisting of: forsterite, cordierite, mullite. These materials or material groups have a very high heat capacity. In addition, they are stable at the desired application temperature. However, other ceramic materials and metallic or polymeric materials are conceivable, without departing from the scope of the invention.

Furthermore, it is advantageous if the proportion of the heat buffer particles is in a range from greater than or equal to 1% by weight to less than or equal to 13% by weight, based on the total weight of the coating compound. By this measure, the

Heat capacity of Umhüllmasse be further increased.

It is also advantageous if the heat buffer particles are arranged in the cement paste. Accordingly, the heat buffer particles are enveloped by the cement paste. in this connection the heat buffer particles are preferably distributed homogeneously in the cement paste. As a result of this measure, the amount of heat emitted by the electrical component can be released very well via the cement paste to the heat buffer particles or absorbed by the heat buffer particles.

drawings

The invention will now be described by way of example with reference to the accompanying drawings. Show it:

Fig. 1 is an illustration of an electrical device according to a

Embodiment of the present invention.

In Fig. 1, an electrical device according to the invention is shown, which is provided in its entirety by the reference numeral 10.

The electrical device 10 has an electrical component 12. The

electrical component 12 is formed as a semiconductor device 12. The

electrical component 12 is arranged on a carrier substrate 14. Between the electrical component 12 and the carrier substrate 14, a copper layer 16 is arranged. The copper layer 16 in this case has several functions, namely to improve the heat connection and removal, an electrical

Provide contacting possibility for the electrical component 12 and possibly as a flow stop the Umhüllmasse during application.

The electrical component 12 is connected via bonding wires 18 with him

opposite side of the carrier substrate 14, whereby an electrical contacting of the electrical component 12 is made possible from the outside. Here, the carrier substrate 14 may, for example, as a plate

be formed, in the further conductor tracks or electrical contacts to

Contacting the electrical component 12 may be integrated. The

Conductor tracks can also be on a surface of the carrier substrate 14

be arranged. The carrier substrate 14 may be formed into a chip. The electrical device 10 also has an encasing compound 20, which has a cement compound 22. The wrapping compound 20 or the cement compound 22 is formed as a glob top. The wrapping compound 20 or the cement compound 22 is arranged on the carrier substrate 14. The cement compound 22 in this case encloses the electrical component 12 on the surfaces which are uncovered by the carrier substrate 14. Accordingly, the electrical component 12 is completely enveloped by the carrier substrate 14 and the encasing compound 20. The cement compound 22 also also covers a part of the carrier substrate 14, via which it is firmly connected to the carrier substrate 14.

The wrapping compound 20 or the cement paste 22 has a plurality of

Heat buffer particles 24 on. The heat buffer particles 24 are arranged distributed in the interior of the cement mass 22. Accordingly, the heat buffer particles 24 are enveloped by the cement paste 22. According to the invention

Heat buffer particles 24 a particulate material, which has a higher

Heat capacity than the cement 22 has the cement mass. Thus, the Umhüllmasse invention 20 due to the heat buffer particles 24 has a higher heat capacity than a wrapping compound 20 with, for example. Only the cement paste 22. One of the electrical component 12 delivered

Amount of heat 26 can thus be taken up particularly efficiently by the heat buffer particles 24. The heat buffer particles 24 can after recording slowly release the absorbed amount of heat 26 to the environment of the electrical device 10, so that prevents the

Envelope 20 and the electrical component 12 to reach a critical temperature and thereby damaged. Accordingly, it is possible according to the invention to achieve a very high thermal overload capacity and thereby to ensure safe operation and protection of the electrical component 12 from overheating, in particular during power loss peaks.

In the manufacture of the electrical device 10 is first the

Cement material 22, for example, provided in powder form. In the cement paste 22, the heat buffer particles 24, which may, for example, also be present in powder form, then mixed. Subsequently, a liquid component, for example. Water is mixed with possibly the flux Melflux. The wet encapsulant 20 comprising the cement paste 22, the heat buffer particles 24 and the water is then evacuated, applied to the electrical component 12 and brought into shape, eg. By injection molding or casting into molds. Subsequently, the Umhüllmasse 20 is heat treated or tempered, for example. At 60 ° C and 90% relative humidity, whereby a

Gelation, crystallization, needling and curing of the cement paste 22 takes place. In this case, the humidity prevents water loss (water-cement value) and the temperature causes a formation of the desired

Structures. Finally, the wrapping compound 20 is optionally treated with the heat buffer particles 24, then removed from the mold and removed, for example at 300 ° C.

Claims

claims 1) Electrical device with an electrical component (12) which is at least partially enveloped by a coating mass (20) comprising a cement compound (22), characterized in that the enveloping mass (20) furthermore  Heat buffer particles (24) which are arranged in the cement paste (22) and have a particulate material or consist of a particulate material having a higher heat capacity than the cement of the cement paste (22). 2) An electrical device (10) according to claim 1, characterized in that the cement paste (22) comprises alumina cement or consists of alumina cement. 3) Electrical device (10) according to claim 1 or 2, characterized in that the heat capacity of the particulate material is in a range of greater than or equal to 900 J / kgK. 4) Electrical device (10) according to one of the preceding claims, characterized in that the particulate material is selected from the group consisting of: forsterite, cordierite, mullite. 5) Electrical device (10) according to one of the preceding claims, characterized in that the proportion of the heat buffer particles (24) in a range of greater than or equal to 1 wt .-% to less than or equal to 13 wt .-% based on the total weight of Enveloping compound (20) is located. 6) Electrical device (10) according to any one of the preceding claims, characterized in that the heat buffer particles (24) are arranged in the cement compound (22). 7) Electrical device (10) according to one of the preceding claims, characterized in that the electrical component (12) is a semiconductor component (12), a sensor element, an inductance, a capacitance, a battery cell, a battery module or a circuit. Method for producing an electrical device (10) with a electrical component (12) which is at least partially enveloped by an encasing compound 0 having a cement compound (22), in particular according to one of the preceding claims, with the following steps:  Providing the cement paste (22);  Mixing thermal buffer particles (24) into the cementitious mass (24), wherein the thermal buffering particles (24) comprise a particulate material or consist of a particulate material having a higher heat capacity than the cementitious cementitious mass (22);  Applying the cement paste (22) with the heat buffer particles (24) having Umhüllmasse (20) on the electrical component (12); and  Heat treating the wrapping compound (20). Use of a mass comprising a cement paste (22) and A heat buffer particle (24) as an encapsulation compound (20) for an electrical component (12) of an electrical device (10), in particular according to one of claims 1 to 7 or produced according to claim 8, wherein the heat buffer particles (24) are arranged in the cement compound (22) are and have a particulate material or consist of a particle material having a higher heat capacity than the cement of the cement paste (22).