JP2018536996A - Electrical device with coating - Google Patents

Abstract

  Disclosed is an electrical device (10) comprising an electrical component (12) that is at least partially coated with a dressing (20) comprising a cement material (22). The dressing (20) includes thermal buffer particles (24), the thermal buffer particles (24) being disposed within the cement material (22) and further the amount of heat released from the electrical component (12). The phase transition proceeds while absorbing at least part of (26).

Description

  The present invention relates to an electrical device comprising an electrical component that is at least partially coated with a coating material, and to a method for manufacturing such an electrical device.

BACKGROUND OF THE INVENTION Increased reliability and efficiency and reduced cost of power electronics modules and rugged sensor systems are of utmost importance today. Current coating materials (epoxy compounds, silicone materials) are limited to a temperature range below 200 ° C. By developing a temperature range up to 300 ° C to 350 ° C for coatings, modern power semiconductors (eg SiC) without having to give up the added functionality of the coating (eg protection against environmental conditions, thermal improvements) Can be expanded to over 200 ° C.

  From German Offenlegungsschrift 10 20 131 12267 (DE 10201131267 A1), a semiconductor module with a covering material made of various types of cement for covering semiconductor components is known. In this case, the coating material contains an additive having a high thermal conductivity.

German Patent Application Publication No. 10201131267

DISCLOSURE OF THE INVENTION The subject of the present invention is an electrical device comprising an electrical component that is at least partially coated with a dressing comprising a cement material, the dressing further comprising thermal buffer particles, the thermal buffer particles comprising cement In addition to being disposed within the material, it is further configured to undergo phase transition while absorbing at least a portion of the amount of heat released from the electrical components.

The subject of the present invention is also a method of manufacturing an electrical device comprising an electrical component that is at least partially coated with a coating material comprising a cement material,
-Preparing the cement material;
-Mixing heat buffer particles formed so that the phase transition proceeds while absorbing at least part of the amount of heat released from the electrical components into the cement material;
-Applying a covering material comprising a cement material mixed with heat buffer particles to the electrical component such that the covering material at least partially covers the electrical component;
-Heat treating the coating;
Have

  The subject of the invention is also the use of a material comprising a cement material and a heat buffer particle as a coating for an electrical component of an electrical device, in which case the heat buffer particle is arranged in the cement material In addition, the phase transition proceeds while absorbing at least a part of the amount of heat released from the electrical component.

  The electrical component may be, for example, a semiconductor component, a sensor element, an inductance, a capacitance, a battery cell, a battery module, or an entire circuit. However, an electrical component may mean any active / passive component or high power component within the framework of the present invention. In this case, the electrical device may have a support substrate on which electrical components are arranged.

  Cement may mean an inorganic, metal-free hydrobinder within the framework of the present invention. In this case, the cement hardens in water, i.e. chemically reacts with water to form a stable compound that does not decompose. In this case, the cement is formed as a finely divided powder that reacts with water or added water to condense and harden to form a hydrate at the start of the process or prior to hydration. It should be. In this case, the hydrates should form needles and / or platelets that mesh with each other and thus provide high strength of the cement. In contrast, phosphate cement does not harden in water. An acid / base reaction is performed to form a salt gel, which is subsequently condensed to a mostly amorphous material. In the acid / base reaction, H + (hydrogen ion) is exchanged.

The cement may consist primarily of calcium aluminate and may form calcium aluminate hydrate during hydration. It is advantageous if the cement material comprises alumina cement, in particular if it comprises alumina cement. Alumina cement (abbreviated CAC) is conditioned in European style according to DIN EN 14647. Alumina cement is mainly composed of monocalcium aluminate (CaO ^* Al ₂ O ₃ ).

The alumina cement has, for example, the following composition:
-Al ₂ O _3: 67.8 wt% or more -CaO: 31.0 wt% -SiO _2: 0.8 wt% or less _-Fe 2 _O 3: and those having a 0.4 wt% or less Good.

  Thermal buffer particles may mean particulate additives within the framework of the present invention. The heat buffer particles may be formed into a powder before the step of mixing in the cement material. However, the heat buffer particles may contain a liquid component. Thus, the heat buffer particles may be present as, for example, a water-containing solution or dispersion or suspension. The heat buffer particles may be incorporated into the dry cement material or cement powder mixture, i.e. optionally before the added water is added. However, the heat buffer particles may also be incorporated into the wet cement material or cement powder mixture, i.e. optionally after the added water has been added. The heat buffer particles may have a particle diameter D50 in the range of 0.1 μm to 0.4 mm.

  In this case, the heat buffer particles are formed so that the phase transition proceeds while absorbing a specific amount of heat. The phase transition may mean a change in the aggregation state within the framework of the present invention, and the temperature of the heat-buffered particles changes at this time with little or no change. In this case, the heat buffer particles are formed so as to shift from a solid state to a liquid aggregation state when absorbing the amount of heat released from the electrical component. As the material melts, i.e., transitions from the solid phase to the liquid phase, heat is consumed or absorbed, and this heat is potentially stored as long as the liquid state continues to exist, and this latent It is known that the typical heat is released again at the time of condensation, ie at the transition from the liquid phase to the solid phase.

The covering material may mean any kind of sealing means (package) within the framework of the present invention. The covering material may be formed as a cement composite material. That is, in other words, the coating material may include a cement matrix including a filler and heat buffer particles. The dressing has the following composition:
-Binder Alumina cement: 8% to 47% by weight (for example, SECAR71)
-Reactant water: 10 wt% to 28 wt%-Heat buffer particles: 4 wt% to 30 wt%-Filler: 25 wt% to 82 wt%

The filler is
-Al ₂ O ₃ : Fine d50 about 1 μm to coarse d50 about 150 to 200 μm
-Α-type Si ₃ N ₄ : thin approximately 1 μm to coarse approximately 100 μm
-Hex. BN: Fine approximately 15 μm to coarse approximately 250 μm
-SiC: Fine about 10-50 μm to coarse about 600 μm
-AlN: Fine about 1 μm to coarse about 100 μm
It may be selected from the group consisting of:

  In the frame of the present invention, the heat treatment step may include a hydration step and / or a setting step and / or a drying step and / or a curing step. The heat treatment may include a tempering step in a tempering furnace. The heat treatment is preferably performed in a temperature range of 40 ° C. to 95 ° C.

  Therefore, in the present invention, the thermal characteristics of the coating material are required based on the addition of the heat buffer particles formed so that the phase transition proceeds while absorbing at least a part of the heat released from the electrical component. It is possible to make an appropriate adjustment according to the above, and in particular, to greatly improve the heat absorption of the covering material. In other words, rather than trying to increase the thermal conductivity of the coating in order to release the heat from the electrical components to the surrounding environment as quickly as possible, it is rather based on an improvement in heat absorption by phase transition. High thermal buffering and thus thermal overload capability is achieved. In this case, the thermal buffering is performed by absorbing heat as transition energy, for example, melting heat. In this case, the present invention keeps the temperature of the thermal buffer particles substantially constant despite the heat absorption during the phase transition or during the phase transition, and thus temporarily absorbs extremely high pulse loss power by the thermal buffer particles. In this case, the coating material or the electric component is not thermally loaded.

  That is, the thermal conductivity of the dressing may be set relatively low to favor the heat capacity depending on the load during curing or operation, thereby reducing the thermal conductivity and heat capacity for the particular application. Specific optimal conditions can be achieved and thus the operating state can be adjusted or optimized. Accordingly, it is possible to provide an electric device that is particularly strong even if the loss power peak during operation is high and that protects electric components from overheating.

  Further advantageous is the case where the heat buffer particles are formed such that the phase transition of the heat buffer particles is reversible and the phase transition proceeds while releasing at least part of the amount of heat absorbed by the electrical components. . In this case, for example, the solid heat buffer particles are first melted while absorbing the amount of heat, and then the heat amount is released at a low speed to be condensed again. On the basis of this measure, the heat absorption process and the heat release process can be repeated in sequence, so that long-term overheating protection of the electrical components can be ensured.

  Furthermore, it is advantageous if the heat buffer particles comprise or consist of a material having a phase transition temperature in the range from 150 ° C. to 350 ° C., in particular about 300 ° C. Based on this measure, the heat absorption of the coating can be further improved, and the amount of heat from the electrical components up to an operating temperature of up to 350 ° C. can be absorbed and re-released very efficiently. become able to.

  It is also advantageous if the thermal buffer particles comprise or consist of a material selected from the group consisting of phase change materials, metals, metal alloys, in particular In-Bi-Sn, plastics and glasses. Each of the above materials has very good phase transition characteristics. Each of the above materials further has a phase transition temperature of about 300 ° C.

  Further, it is advantageous that the amount of the heat buffer particles is in the range of 4% by weight to 30% by weight with respect to the total weight of the coating material. Based on this means, the heat absorption of the covering material can be further improved.

  It is also advantageous if the heat buffer particles are arranged in the cement material. Thereby, the heat buffer particles are coated with the cement material. In this case, the heat buffer particles are preferably uniformly dispersed in the cement material. Based on this measure, the quantity of heat released from the electrical component can be supplied very well to the thermal buffer particles via the cement material or absorbed by the thermal buffer particles.

  In addition, it is advantageous to provide an electrical insulation layer arranged between the dressing and the electrical component. In this case, the electrical insulating layer preferably comprises or consists of alumina cement. The electrically insulating layer is preferably free of heat buffer particles, i.e. has no heat buffer particles. This measure ensures that when the thermal buffer particles are conductive, the electrical components are electrically isolated from the coating containing the conductive thermal buffer particles so that no short circuit occurs. .

  It is further advantageous to provide a shielding layer which is arranged on one surface of the cement material and which is formed so as to prevent the thermal buffer particles from leaking out of the gas phase. In particular, the gas phase generated during operation of the electrical device, i.e. when the thermal buffer particles proceed with the phase transition, can leak out of the coating. In order to prevent this, the coating material can be sealed with a shielding layer to prevent vaporization or leakage of the thermal buffer particles from the coating material. Undesirable leakage of the thermal buffer particles in the gas phase can change the stoichiometry of the alloy and thus the properties of the coating, condensing the vapor in the coating, and can additionally impact the environment.

  It is also advantageous if the shielding layer comprises or consists of a material selected from the group consisting of monomers, polymers, in particular silicone, and inorganic materials, in particular oxides, nitrides, ceramics. . Each of the above materials is particularly well suited because it has very good gas or vapor shielding properties.

  The present invention will be described in more detail with reference to the accompanying drawings exemplified below.

FIG. 2 shows an electrical device according to one embodiment of the present invention. FIG. 6 shows an electrical device according to another embodiment of the invention.

  FIG. 1 shows an electrical apparatus according to the present invention, generally designated by reference numeral 10.

  The electrical device 10 has an electrical component 12. The electrical component 12 is formed as a semiconductor component 12. The electrical component 12 is disposed on the support substrate 14. A copper layer 16 is disposed between the electrical component 12 and the support substrate 14. In this case, the copper layer 16 has a plurality of functions, i.e., a function of improving thermal connection and heat dissipation, a function of providing an electrical contact connection means to the electrical component 12, and, in some cases, of the coating material when being applied. It has a function as a flow stop.

  The electrical component 12 is connected to the side of the support substrate 14 opposite to the electrical component 12 via the bonding wire 18, and thereby makes electrical contact with the electrical component 12 from the outside. It becomes possible. In this case, for example, the support substrate 14 may be formed as a plate into which a conductor path for electrical connection of the electrical component 12 or an electrical contact can be further incorporated. The conductor path may be disposed on one surface of the support substrate 14. The support substrate 14 may be formed so as to form a chip.

  The electric device 10 further includes a covering material 20 including a cement material 22. The covering material 20 or the cement material 22 is formed as a glob-top. The covering material 20 or the cement material 22 is disposed on the support substrate 14. In this case, the cement material 22 covers the electrical component 12 on the surface not covered with the support substrate 14. Therefore, the electrical component 12 is entirely covered with the support substrate 14 and the covering material 20. The cement material 22 further covers a part of the support substrate 14, and the cement material 22 is firmly bonded to the support substrate 14 through this part.

  The covering material 20 or the cement material 22 includes a large number of heat buffer particles 24. These heat buffer particles 24 are dispersed and arranged in the cement material 22. Therefore, the heat buffer particles 24 are covered with the cement material 22. In the present invention, the heat buffer particles 24 include a particulate material that is formed so that the phase transition proceeds while absorbing at least a portion of the amount of heat 26 emitted from the electrical component 12. Therefore, the covering material 20 according to the present invention has higher heat absorption than the covering material 20 having only the cement material 22 based on the heat buffer particles 24, for example. Therefore, the heat particles 24 store the amount of heat 26 released from the electrical component 12, and the phase of the heat particles 24 changes at that time, and for example, melts starting from a solid state. Therefore, it can absorb especially efficiently. In this case, the heat buffer particles 24 may release the absorbed amount of heat 26 to the surrounding environment of the electric device 10 at a low speed after the phase transition. During the phase transition, the temperature of the thermal buffer particles 24 is kept approximately constant despite heat absorption or rises only very slightly, so that the thermal buffer particles 24 temporarily cause a very high pulse loss power. In this case, the covering 20 or the electrical component 12 is not thermally loaded. Thus, in the present invention, it is possible to achieve a very high thermal overload capability and thereby ensure reliable operation and protection of the electrical component 12 against overheating, especially during peak power losses. is there.

  The electrical device 10 further includes an electrical insulating layer 28. The electrical insulating layer 28 is disposed between the covering material 20 and the electrical component 12. The electrical insulating layer 28 is formed as a glob top. The electrical insulation layer 28 covers the electrical component 12 and thus forms an electrical insulation means for the electrical component 12. Thereby, for example, when the heat buffer particles 24 are formed to be conductive, an electrical short circuit can be prevented.

  The electrical device 10 further includes a shielding layer 30. The shielding layer 30 is disposed on one surface 32 of the covering material 20 or the cement material 22. The shielding layer 30 is formed so as to be closed, thereby forming a kind of gas shield or vapor shield for the covering material 20. Thereby, for example, the gas phase of the thermal buffer particles 24 generated at the time of phase transition can be prevented from leaking from the coating material 20.

  FIG. 2 shows another electrical device 10 'according to the present invention. The electric device 10 'is configured in the same manner as the device 10 shown in FIG. However, the electrical insulating layer 28 ′ included in the electrical device 10 ′ is formed as a thin film. The electrically insulating layer 28 ′ extends over the entire interface between the covering 20 and the electrical component 12 or the support substrate 14.

  At the time of manufacturing the electric devices 10 and 10 ′ according to the present invention, first, the cement material 22 is prepared in a powder form, for example. The cement material 22 is then mixed with heat buffer particles 24, which may also be in powder form, for example. A liquid component, such as water, is then mixed, optionally with a solvent melflux. The moist dressing 20 containing the cement material 22, the heat buffer particles 24 and water is then evacuated and applied to the electrical component 12 and molded, for example, by injection or casting into a mold. Next, the covering material 20 is heat-treated or malleable, for example, at 60 ° C. and a relative air humidity of 90%, whereby the gelation, crystallization, needling and hardening of the cement material 22 are performed. In this case, air humidity prevents moisture loss (water / cement ratio) and heat causes the formation of the desired structure. Finally, heat buffer particles 24 are optionally applied to the dressing 20 and then released from the mold, for example at 300 ° C.

  Additionally, a wet cement material that is additionally free of heat buffer particles may be prepared according to the steps described above at the start of production. In this case, the cement material can be applied as an electrical insulating layer 28 to the electrical component 12 and possibly to the support substrate 14 prior to the application of the coating 20 containing the thermal buffer particles 24. However, the electrical insulation layer 28 may be disposed between the electrical component 12 and the dressing 20 in any form well known to those skilled in the art without departing from the scope of the present invention.

  Further additionally, the shielding layer 30 is applied to the surface 32 of the dressing 20 or cement material 22 in any manner known to those skilled in the art, for example by injection or pouring of the shielding layer 30 onto the dressing 20 or by immersion water. You may adhere by immersing the coating | covering material 20 in the.

Claims (15)

In an electrical device comprising an electrical component (12) at least partially coated with a dressing (20) comprising a cement material (22),
The covering (20) includes thermal buffer particles (24), the thermal buffer particles (24) being disposed within the cement material (22) and further from the electrical component (12). An electrical device characterized in that the phase transition proceeds while absorbing at least part of the amount of heat (26) released.   The electrical device (10) according to claim 1, wherein the cement material (22) comprises or consists of alumina cement.   The phase transition of the thermal buffer particles (24) is reversible, and the thermal buffer particles undergo phase transition while releasing at least part of the amount of heat (26) absorbed by the electrical component (12). The electrical device (10) according to claim 1 or 2, wherein the electrical device (10) is formed as follows.   The heat-buffering particles (24) are formed to transition from a solid to a liquid agglomerated state upon absorption of heat (26) emitted from the electrical component (12). Electrical device (10) according to any one of the preceding claims.   5. The heat buffer particle (24) comprises or consists of a substance having a phase transition temperature in the range from 150 ° C. to 350 ° C., in particular about 300 ° C. 5. The electrical device (10) according to one paragraph.   The heat buffer particles (24) comprise or consist of a material selected from the group consisting of phase change materials, metal alloys, in particular In-Bi-Sn, plastics and glasses. The electrical device (10) according to any one of claims 5 to 10.   The amount of the heat buffer particles (24) is in the range of 4 wt% to 30 wt% with respect to the total weight of the covering material (20). Electrical device (10).   The electrical device (10) according to any one of the preceding claims, wherein the thermal buffer particles (24) are arranged in the cement material (22).   The electrical device (10) according to any one of the preceding claims, wherein an electrical insulation layer (28) is arranged between the covering (20) and the electrical component (12). .   The electrical device (10) according to claim 9, wherein the electrical insulation layer (28) comprises or consists of alumina cement.   A shielding layer (30) is provided on one surface (32) of the cement material (22), and is further formed to prevent the thermal buffer particles (24) from leaking out in the gas phase. Electrical device (10) according to any one of the preceding claims.   Said shielding layer (30) comprises or consists of a material selected from the group consisting of monomers, polymers, in particular silicone, and inorganic materials, in particular oxides, nitrides, ceramics. Item 12. The electrical device (10) according to Item 11.   The electrical device (1) according to any one of the preceding claims, wherein 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. (10). 14. Manufacturing an electrical device (10) comprising an electrical component (12) coated at least partly with a coating (20) comprising a cement material (22), in particular according to any one of claims 1 to 13. A method for
-Preparing the cement material (22);
-Mixing the cement material (22) with heat buffer particles (24) formed so that the phase transition proceeds while absorbing at least part of the amount of heat (26) released from the electrical component (12) And steps to
-Applying the covering (20) comprising the cement material (22) mixed with the heat buffer particles (24) to the electrical component (12);
-Heat treating said dressing (20);
Having a method.   The heat buffer particles arranged in the cement material (22) and formed so that the phase transition proceeds while absorbing at least part of the amount of heat (26) released from the electrical component (12). Electrical device (10) according to any one of claims 1 to 13, or an electrical device manufactured by the method according to claim 14, of a material comprising (24) and a cement material (22). Use as a covering material (20) for an electrical component (12) of (10).

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