CN116936499A

CN116936499A - Electronic device and surface processing method thereof

Info

Publication number: CN116936499A
Application number: CN202310795064.4A
Authority: CN
Inventors: 王广平; 洪芳军; 陈杰; 赵舒然
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-10-24

Abstract

The application provides an electronic device and a surface processing method thereof, wherein the electronic device comprises a heat dissipation substrate and a heating chip connected with the heat dissipation substrate, and the method comprises the following steps: a first mask body is arranged on one side of the heat dissipation substrate far away from the heating chip, and the first mask body is provided with a first through hole; spraying metal powder on the surface of the first mask body by adopting a cold spraying process, so that the metal powder is deposited on the surface of the first mask body and the first through hole area of the first mask body; and removing the first mask body to form a pore structure on the surface of the electronic device. According to the application, the surface of the electronic device is processed by virtue of the cold spraying low-temperature process, so that the porosity of the surface of the electronic device is increased, the boiling heat exchange performance of the electronic device can be improved, and the heat dissipation of the electronic device is accelerated. In addition, the application adopts a low-temperature process, can avoid the influence of a high-temperature process on the internal chip of the electronic device, has better manufacturing stability and can be manufactured and used in a large scale.

Description

Electronic device and surface processing method thereof

Technical Field

The application relates to the technical field of material processing, in particular to an electronic device and a surface processing method thereof.

Background

With the rapid development of the emerging fields of mobile internet, cloud computing, big data, artificial intelligence and the like, the integration level of electronic devices is improved, the power consumption density of chips is also increased, and the traditional heat dissipation modes of air cooling, liquid cooling and the like cannot meet the increasing heat dissipation demands of high-power density devices (such as insulated gate bipolar transistors (insulated gate bipolar transistor, IGBT)).

Boiling phase change heat exchange is often used in a high heat flux density scene, and has a higher heat exchange coefficient compared with the technologies such as air cooling, liquid cooling and the like, so that the boiling phase change heat exchange has great significance for effectively solving the heat dissipation problem of a high-power density device. In boiling phase conversion heat, the heat exchange capacity has strong correlation with the surface treatment process, and the larger the surface porosity of the electronic device is, the stronger the boiling heat exchange capacity is, so that the improvement of the surface porosity of the electronic device is one of the main research directions at present.

Disclosure of Invention

The application provides an electronic device and a surface processing method thereof, and aims to improve the surface porosity of the electronic device so as to accelerate the heat dissipation of the electronic device.

In a first aspect, there is provided a surface processing method of an electronic device including a heat dissipation substrate and a heat generating chip connected to the heat dissipation substrate, the method including: a first mask body is arranged on one side of the heat dissipation substrate far away from the heating chip, and the first mask body is provided with a first through hole; spraying metal powder on the surface of the first mask body by adopting a cold spraying process, so that the metal powder is deposited on the surface of the first mask body and the first through hole area of the first mask body; and removing the first mask body to enable the surface of the electronic device to form a pore structure. The electronic device may be a high power density device (e.g., an IGBT device), among others.

It should be appreciated that after the first mask body is removed, the original first mask body may form an aperture at the location where the first mask body is located.

It should be further understood that the cold spraying low temperature process is used in the present application, and the material of the first mask body is not limited, and the first mask body may be made of metal or non-metal, such as glass, polymer or non-metal.

In the embodiment of the application, the surface of the electronic device is processed through the advantages of a cold spraying low-temperature process and mask etching maturity, so that the porosity of the surface of the electronic device is increased, the boiling heat exchange performance of the electronic device can be improved, and the heat dissipation of the electronic device is accelerated. In addition, the application adopts a low-temperature process, can avoid the influence of a high-temperature process on the internal chip of the electronic device, has better manufacturing stability and can be manufactured and used in a large scale.

With reference to the first aspect, in certain implementation manners of the first aspect, before removing the first mask body, the method further includes: a second mask body is arranged on the surface of the first mask body sprayed with the metal powder, and the second mask body is provided with a second through hole; spraying metal powder on the surface of the second mask body by adopting a cold spraying process, so that the metal powder is deposited on the surface of the second mask body and a second through hole area of the second mask body; wherein the method further comprises: and removing the second mask body.

The electronic device may be an IGBT device, and the first mask body may have a circular hole structure of a 4×4 matrix, where a diameter of the circular hole is 1mm; the second mask body can adopt 5 round hole structures of 2/1/2, and the diameter of the round hole is 2mm. By providing the first through-holes differently than the second through-holes, the pore structure of the deposited layer of each layer is made different.

In the embodiment of the application, the surface of a high-power density device (such as an IGBT) is subjected to secondary processing, namely, a designed mask body (comprising a first mask body and a second mask body) is arranged on the surface of a heat dissipation substrate in advance, powder spraying particles are deposited on a substrate outside the mask body, and then the mask body can be reacted by an etching process, so that the surface of the IGBT device forms a 3D hollow structure, the surface porosity of the IGBT device is increased, and the boiling heat exchange performance can be greatly increased. In addition, can set up different mask bodies, form different pore structures, satisfy the heat transfer demand of different electronic devices.

With reference to the first aspect, in certain implementation manners of the first aspect, the first mask body is made of a metal material, and metal mobility of the first mask body is higher than that of the sprayed metal powder, where removing the first mask body includes: and etching the first mask body by adopting an etching process, so that a pore structure is formed on the surface of the electronic device.

It should be noted that the second mask body may also be removed by the etching process described above.

With reference to the first aspect, in certain implementations of the first aspect, a coefficient of thermal expansion of the first mask body is greater than a coefficient of thermal expansion of the sprayed metal powder, wherein the removing the first mask body includes: and removing the first mask body through thermal expansion and cold contraction, so that a pore structure is formed on the surface of the electronic device.

It should be noted that the second mask body may also be removed by the above-mentioned thermal expansion and contraction method.

In one example, the mask body (including the first mask body and the second mask body) may be made of a metal material (e.g., aluminum, zinc, magnesium, etc.) with higher metal activity than the metal activity of the sprayed metal powder. In this case, the mask body may be removed by an etching process using a chemical method.

For example, the mask body may be made of aluminum, and when the mask body is etched by using an etching process, alkaline sodium hydroxide and aluminum can be used for alkaline reaction, and the chemical reaction formula is as follows: 2al+2h2o+2naoh=2naalo2+3h2Σ, etching the mask body made of aluminum, thereby forming a porous structure, so that the surface of the electronic device forms a pore structure.

In another example, the mask body (including the first mask body and the second mask body) may be selected from a material having a coefficient of thermal expansion greater than that of the sprayed metal powder. That is, the thermal expansion and contraction effect of the mask body is more remarkable than that of the sprayed metal powder, and in this case, the mask body can be removed by a physical method.

In yet another example, the mask body (including the first mask body and the second mask body) may be made of a metal material (e.g., aluminum, zinc, magnesium, etc.) having a higher metal mobility than the metal mobility of the sprayed powder, and a material having a higher coefficient of thermal expansion than the powder material. In this case, the mask body may be removed by either a chemical method or a physical method.

In the embodiment of the application, the mask body can be removed by selecting a proper method (a physical method or a chemical method) according to the material difference between the mask body and the sprayed metal powder, so that a pore structure is formed on the surface of the electronic device.

With reference to the first aspect, in some implementations of the first aspect, a cross section of the first mask body and a cross section of the second mask body are concave, convex or plane, and the cross section is perpendicular to a connection surface of the heat dissipation substrate and the heat generating chip.

It should be understood that, in the embodiment of the present application, the shape of the mask body may not be limited, that is, the cross section of the mask body may be concave, convex or planar, where when the cross sections of the first mask body and the second mask body are convex, the surface heat exchange capability of the electronic device obtained by processing the first mask body and the second mask body is relatively good.

With reference to the first aspect, in some implementations of the first aspect, the setting positions of the first mask body and the second mask body correspond to the hot spot positions of the heat generating chip.

In one example, the projection of the mask body (including the first mask body and the second mask body) on the first plane may cover the hot spot position (i.e., the heat source position) of the heat generating chip, where the first plane is the connection surface of the heat dissipating substrate and the heat generating chip.

In one example, the placement of the mask body (including the first mask body and the second mask body) corresponding to the hot spot position of the heat generating chip may be understood as: the center point of the mask body coincides with the projection of the hot spot of the heating chip along the first direction, and the first direction is a direction perpendicular to the connecting surface of the heat dissipation substrate and the heating chip.

In the embodiment of the application, the mask body is arranged at the hot spot position of the heating chip, so that multiple holes can be arranged at the hot spot position of the IGBT device in a targeted manner, the surface heat exchange capacity of the hot spot position is improved, and the chip overtemperature risk is small.

With reference to the first aspect, in certain implementations of the first aspect, a largest dimension of the aperture formed by the surface of the electronic device is between 0.1 and 2mm.

In the embodiment of the application, the size of the pores is limited, so that the excessive or excessively small pores formed on the surface of the electronic device are avoided, and the boiling heat exchange performance of the electronic device is influenced.

With reference to the first aspect, in certain implementation manners of the first aspect, the method further includes: and manufacturing the first mask body and the second mask body through machining, 3D printing or stamping processes. That is, the mask body in the embodiment of the present application may be manufactured by machining, 3D printing or stamping.

With reference to the first aspect, in some implementations of the first aspect, the disposing a first mask body on a side of the heat dissipation substrate away from the heat generating chip includes: and the first mask body is arranged on one side, far away from the heating chip, of the heat dissipation substrate in a positioning tool, free setting or vacuum adsorption mode. That is, the arrangement modes of the first mask body and the second mask body may include any one of the following: positioning a tool, freely setting and vacuum adsorbing.

In a second aspect, there is provided an electronic device comprising: a heat generating chip; the heat dissipation substrate is fixedly connected with the heating chip; the first porous medium layer is positioned on one side of the heat dissipation substrate far away from the heating chip, and is processed through a cold spraying process and an etching process.

The electronic device provided by the application comprises the first porous dielectric layer, and the first porous dielectric layer can be processed by a cold spraying process and an etching process. That is, the surface of the electronic device can be processed through a cold spraying process and an etching process, so that the porosity of the surface of the electronic device is increased, the boiling heat exchange performance of the electronic device can be improved, and the heat dissipation of the electronic device is accelerated. In addition, the application adopts a low-temperature process, can avoid the influence of a high-temperature process on the internal chip of the electronic device, has better manufacturing stability and can be manufactured and used in a large scale.

With reference to the second aspect, in some implementations of the second aspect, the electronic device further includes a second porous dielectric layer, where the second porous dielectric layer is located on a side of the first porous dielectric layer away from the heat dissipation substrate, and the second porous dielectric layer is processed by a cold spraying process and an etching process.

In the embodiment of the application, the surface of the electronic device can be processed to form a plurality of porous medium layers (namely a plurality of pore structure layers), so that the porosity of the surface of the electronic device can be further increased, the boiling heat exchange performance of the electronic device can be further improved, and the heat dissipation of the electronic device can be further accelerated.

With reference to the second aspect, in some implementations of the second aspect, the pores of the first porous medium layer may be disposed corresponding to the hot spot positions of the heat generating chip.

In one example, the placement of the pores of the first porous medium layer corresponding to the hot spot locations of the heat generating chip can be understood as: the aperture of the first porous medium layer coincides with the projection of the hot spot of the heating chip along the first direction, and the first direction is the direction perpendicular to the connecting surface of the heat dissipation substrate and the heating chip.

Similarly, the pores of the second porous medium layer may also be disposed corresponding to the hot spot positions of the heat generating chip.

In the embodiment of the application, the porous characteristic can be customized and formed aiming at the hot spot position of the heating chip, so that the boiling heat exchange performance at the hot spot position can be quickened, the surface heat exchange capacity at the hot spot position is improved, and the chip overtemperature risk is small.

With reference to the second aspect, in certain implementations of the second aspect, a largest dimension of the pores of the first porous medium layer is between 0.1 and 2mm.

Similarly, the largest dimension of the pores of the second porous medium layer is also between 0.1 and 2mm.

In the embodiment of the application, the pore size is limited, so that the overlarge or undersize pores formed on the surface of the electronic device are avoided, and the boiling heat exchange performance of the electronic device is influenced.

In a third aspect, there is provided an electronic device comprising: the electronic device comprises a heat dissipation substrate and a heating chip connected with the heat dissipation substrate, wherein the surface of the electronic device can be processed by the first aspect or any implementation manner of the first aspect.

The advantages of the third aspect may refer to those of the first aspect or the second aspect, and are not described herein.

Drawings

Fig. 1 is a schematic flow chart of a surface processing method of an electronic device according to an embodiment of the present application.

Fig. 2 is a schematic diagram of a mask body according to an embodiment of the present application.

Fig. 3 is a schematic flow chart of another surface processing method of an electronic device according to an embodiment of the present application.

Fig. 4 is a schematic structural diagram of an electronic device according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of another electronic device according to an embodiment of the present application.

Detailed Description

The technical scheme of the application will be described below with reference to the accompanying drawings.

In order to facilitate understanding of the embodiments of the present application, the following description is made before describing the embodiments of the present application.

In the description of the embodiments of the present application, unless otherwise indicated, "/" means or, for example, a/B may represent a or B; "and/or" herein is merely an association relationship describing an association object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist together, and B exists alone.

In embodiments of the present application, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first", "second" may include one or more features judiciously or implicitly. In addition, in the description of the embodiments of the present application, "plurality" means two or more, and "at least one" and "one or more" mean one, two or more. The singular expressions "a", "an", "the" and "the" are intended to include, for example, also "one or more" such expressions, unless the context clearly indicates the contrary. The sequence numbers of the processes below do not mean the sequence of execution, and the execution sequence of the processes should be determined by the functions and the internal logic, and should not be construed as limiting the implementation process of the embodiments of the present application. For example, in the embodiments of the present application, words "101", "102", "103" and the like are merely identifiers for convenience of description, and do not limit the order of executing steps.

Reference in the specification to "one embodiment" or "some embodiments" or the like means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless expressly specified otherwise.

In the field of boiling heat exchange, a porous structure is generally formed on the surface of an electronic device (namely, a phase change interface) to increase the porosity. The existing scheme is to increase the porosity of the surface of the electronic device through a copper/aluminum powder sintering process. However, when the copper/aluminum powder sintering process is adopted, the stability of the sintering process is poor, the process consistency is difficult to control, and the large-scale commercial use is not possible. In addition, the sintering process is subjected to high temperature, and the internal chip of the electronic device may be softened, broken and the like, which affects the normal use of the electronic device.

Therefore, the embodiment of the application provides the electronic device and the surface processing method thereof, which are used for processing the surface of the electronic device through the advantages of a cold spraying low-temperature process and the mask etching maturity, increasing the porosity of the surface of the electronic device and improving the boiling heat exchange performance of the electronic device so as to accelerate the heat dissipation of the electronic device. In addition, the application adopts a low-temperature process, can avoid the influence of a high-temperature process on the internal chip of the electronic device, has better manufacturing stability and can be manufactured and used in a large scale.

Before describing the method provided by the embodiment of the present application, the technical terms related to the present application will be explained first.

The sintering process refers to a process in which a powder or powder compact is heated to a temperature lower than the melting point of the essential components thereof and then cooled to room temperature in a certain method and speed. As a result of sintering, bonding occurs between the powder particles, and the strength of the sintered body increases, turning the aggregates of powder particles into agglomerates of grains, thereby obtaining the desired physical, mechanical properties of the article or material.

The cold spray process is a new type of surface coating technology developed in recent years. Cold spraying is a process that uses high velocity gas to accelerate micron-sized particles (-5-50 μm) at lower temperatures (-600 ℃) so that they strike the substrate at high velocity (-300-1200 m/s) in a fully solid state, and material deposition is achieved by severe plastic deformation at the particle-substrate interface. The lower gas temperature can avoid thermal effects such as oxidation, phase change, grain growth, etc. in conventional thermal spray processes of powders. At the same time, the higher particle speed is favorable for the particles to generate sufficient plastic deformation in the deposition process so as to obtain a deposition body with compact tissue. These characteristics make cold sprayed metal/metal based coatings generally excellent in terms of high electrical conductivity, high thermal conductivity, high corrosion resistance, high wear resistance, etc.

Because cold spray techniques are low temperature processes, they offer many advantages over other surface treatment methods (e.g., thermal spray), generally produce copper coatings on substrates, thereby improving boiling heat transfer properties of the evaporating surfaces.

Photomasks (also known as photomasks, reticles, photolithographic reticles, as a pattern transfer tool or master in the microelectronic manufacturing process, carry pattern design and process technology information and are considered "negatives" of the photolithographic process. The downstream enterprises use the finished product mask to print the designed circuit pattern on the downstream processing materials in a light exposure (light transmission or non-light transmission) mode. The downstream enterprises can copy the graphic design and the process technical information carried on the mask plate and realize mass production, so that the technology has important influence on the quality and the precision of downstream products. The mask is applied to the industries of semiconductor chips, flat panel displays, touch control, circuit boards and the like. The mask body is a kind of mask.

Etching techniques are techniques that use chemical reactions or physical impact to remove portions of the material. Typically, the mask body may be used in combination with an etching technique by which the mask body is removed (i.e., an etching process).

Porosity refers to the percentage of the pore volume in a bulk material to the total volume of the material in its natural state. It can be understood that in boiling phase conversion heat, the larger the porosity of the surface structure of the electronic device is, the more bubbles are generated, and more heat can be taken away, so that the heat dissipation of the electronic device is facilitated.

The coefficient of thermal expansion can be used to measure the degree of thermal expansion of a solid material. The thermal expansion coefficient is the relative change in length or volume of an object per unit length or volume when the temperature is increased by 1 ℃. It will be appreciated that the greater the coefficient of thermal expansion of the object, the more pronounced is the effect of thermal expansion and contraction.

Fig. 1 is a schematic flow chart of a surface processing method of an electronic device according to an embodiment of the present application. The method may include steps 101 to 104, each of which will be described in detail below.

101, preparing the electronic device 110 to be heat-dissipated and the mask body 120.

The electronic device 110 to be cooled may be a high-power density device (e.g., an IGBT), the electronic device 110 to be cooled may include a heat generating chip 111 and a heat dissipating substrate 112 fixed on one side of the heat generating chip 111, and the heat dissipating substrate 112 may serve as a heat sink, and is mainly used for dissipating heat of the heat generating chip 111. A heat sink is understood to mean a device in which the temperature of an object does not change with the amount of thermal energy transferred to the object, and industry may refer to a micro-heat sink for cooling an electronic chip.

In some embodiments, the heat dissipation substrate 112 may be made of a metal material, such as aluminum, copper, etc., which is not limited in the present application. The mask body 120 can be manufactured by machining, 3D printing, stamping and other machining modes.

In some embodiments, the mask body 120 may be configured as shown in fig. 2, and the mask body 120 may be provided with at least one through hole 121, where the through hole 121 may be circular, rectangular, diamond, etc., and the present application is not limited thereto. In one example, as shown in (a) of fig. 2, the through holes 121 on the mask body 120 may be circular. In another example, as shown in (b) of fig. 2, the through hole 121 on the mask body 120 may have a rectangular shape. In yet another example, as shown in fig. 2 (c), the through holes 121 on the mask body 120 may have a diamond shape.

It should be understood that the cold spraying low temperature process is used in the present application, and the material of the mask body 120 is not limited, and the mask body 120 may be made of metal or nonmetal, such as glass, polymer or nonmetal.

In some embodiments, the mask body 120 may be made of a metal material with high metal mobility (e.g., aluminum, zinc, magnesium, etc.), and the mask body 120 may have a metal mobility higher than that of the sprayed powder. In this case, the mask body 120 may be chemically removed in step 104.

In other embodiments, the mask body 120 may be made of a material having a thermal expansion coefficient greater than that of the powder sprayed on the surface of the mask body 120. That is, the thermal expansion coefficient of the mask body 120 is larger than that of the sprayed powder, that is, the thermal expansion and contraction effect of the mask body 120 is more remarkable than that of the sprayed powder, in which case the mask body 120 may be physically removed in step 104.

In still other embodiments, the mask body 120 may be made of a metal material (e.g., aluminum, zinc, magnesium, etc.) having a higher metal mobility than the metal mobility of the sprayed powder, and a material having a higher coefficient of thermal expansion than the powder material. In this case, the mask body 120 may be removed in step 104 either chemically or physically.

It should be noted that, in the embodiment of the present application, the shape of the mask body 120 is not limited, and the cross section of the mask body 120 may be concave, convex, and plane, where the cross section is perpendicular to the connection surface of the heat dissipation substrate 112 and the heat generating chip 111. It should be appreciated that when the cross-section of the mask body 120 is convex, the surface heat exchanging capability of the electronic device fabricated by disposing the mask body 120 is relatively good.

In some embodiments, the mask body 120 may be a unitary structure or a multi-body structure. It should be understood that in the embodiment of the present application, the required mask body 120 may be set according to the size of the area of the electronic device 110 to be heat-dissipated. In one example, considering that the area to be heat-dissipated of the electronic device 110 to be heat-dissipated is large, the required mask body 120 is large, in this case, the mask body 120 of a multi-body structure may be disposed, so that the mask body 120 of a multi-body structure may cover the portion to be heat-dissipated. In another example, if the area to be heat-dissipated of the electronic device 110 is smaller, the mask body 120 may be an integral structure. That is, the mask body 120 with an integral structure may cover the portion to be heat-dissipated of the electronic device 110.

102, a mask body 120 is disposed on a side of the heat dissipation substrate 112 away from the heat generating chip 111.

The mask body 120 is disposed in the following manners, but not limited to: positioning tools, free setting, vacuum adsorption and the like. That is, in this step, the mask body 120 may be disposed on the side of the heat dissipation substrate 112 away from the heat generating chip 111 by means of a positioning tool, free setting or vacuum adsorption.

It should be noted that, the position where the mask body 120 is disposed may correspond to the position where heat dissipation is required on the electronic device 110 to be dissipated, that is, the position where the mask body 120 is disposed corresponds to the hot spot position of the heat generating chip 111.

In one example, the projection of the mask body 120 on the first plane may cover the hot spot position (i.e., the heat source position) of the heat generating chip 111, where the first plane is a connection surface between the heat dissipating substrate 112 and the heat generating chip 111.

In one example, the location of the mask body 120 corresponding to the hot spot location of the heat generating chip 111 may be understood as: the center point of the mask body 120 coincides with the projection of the hot spot of the heat generating chip 111 along the first direction, which is a direction perpendicular to the connection surface of the heat dissipating substrate 112 and the heat generating chip 111.

In this example, by disposing the mask body 120 at the hot spot position of the heat generating chip 111, multiple holes can be disposed at the hot spot position of the IGBT device in a targeted manner, so that the surface heat exchange capability at the hot spot position is improved, and the risk of chip overtemperature is small. That is, the mask body 120 may be correspondingly disposed on the high heat-generating portion of the heat-generating chip 111, thereby increasing the porosity at the high heat-generating portion and further enhancing the heat dissipation effect at the hot spot position.

103, spraying powder 130 on the side of the heat dissipation substrate 112 where the mask body 120 is provided.

It should be noted that, the material of the sprayed powder 130 may be higher than the material of the heat dissipation substrate 112, so that the powder 130 may adhere to the heat dissipation substrate 112. Wherein the sprayed powder 130 may be a metal powder (e.g., copper powder) with which heat transfer may be performed.

In some embodiments, the powder 130 may be sprayed to the side of the heat sink base 112 where the mask body 120 is disposed using a cold spray process. It should be appreciated that when the powder 130 is sprayed by the cold spraying process, the material of the mask body 120 is not limited, and the mask body 120 may be made of metal or nonmetal, such as glass, polymer or nonmetal.

In other embodiments, the thermal spraying process may be used to spray the powder 130 to the side of the heat sink base 112 where the mask body 120 is disposed. It should be appreciated that when the powder 130 is sprayed using a thermal spray process, the mask body 120 may be formed of a material that is resistant to high temperatures.

It can be appreciated that when the powder 130 is sprayed onto the side of the heat dissipation substrate 112 where the mask body 120 is disposed, the sprayed powder 130 may completely cover the mask body 120, i.e., completely wrap the mask body 120; the mask body 120 may be partially covered, i.e., the mask body 120 is half-wrapped; it is also possible to cover only the through holes 121 on the mask body 120, i.e., to spray the powder 130 only to the positions corresponding to the through holes 121.

104, removing the mask body 120 after the spraying is finished, and obtaining the processed high-power density device.

The surface of the processed high-power density device has pores 140, that is, the surface of the electronic device 110 may form a pore structure.

The maximum size of the pores 140 on the surface of the electronic device is between 0.1 and 2mm. By limiting the size of the pores 140, the formation of pores on the surface of the electronic device is avoided from being too large or too small, thereby affecting the boiling heat exchange performance of the electronic device.

It should be noted that, the removing manner of the mask body 120 may include a physical method and a chemical method. The physical method mainly relies on the principle of thermal expansion and cold contraction, and the mask body 120 is taken out of the sprayed powder 130 by heating or cooling. The chemical method mainly comprises the step of reacting off the mask body 120 through an etching process, so that a 3D hollow structure is formed on the surface of the electronic device 110.

It can be appreciated that in the embodiment of the present application, the electronic device with different porosities or different pore structures on the surface can be formed by setting the size of the through holes and the density of the through holes on the mask body 120.

Through the steps 101 to 104, that is, through the advantages of the cold spraying low-temperature process and the mask etching maturity, the surface of the electronic device 110 is processed, the porosity of the surface is increased, and the boiling heat exchange performance of the electronic device 110 can be improved, so that the heat dissipation of the electronic device 110 is accelerated. In addition, the application adopts a low-temperature process, can avoid the influence of a high-temperature process on the internal chip of the electronic device 110, has better manufacturing stability and can be manufactured and used in a large scale.

Fig. 3 is a schematic flow chart of another surface processing method of an electronic device according to an embodiment of the present application. The method may include steps 301 to 308, each of which will be described in detail below.

301, preparing an electronic device 310 to be heat-dissipated, a first mask body 320 and a second mask body 330.

The electronic device 310 to be heat-dissipated may include a heat-generating chip 311 and a heat-dissipating substrate 312 fixed on one side of the heat-generating chip 311. It should be understood that the electronic device 310 to be cooled corresponds to the electronic device 110 to be cooled, the heat generating chip 311 corresponds to the heat generating chip 111, and the heat dissipating substrate 312 corresponds to the heat dissipating substrate 112, and the description of the electronic device 310 to be cooled, the heat generating chip 311 and the heat dissipating substrate 312 will be referred to the above description and will not be repeated here.

In some embodiments, the first mask body 320 is provided with a first through hole, and the second mask body 330 is provided with a second through hole, and the first through hole and the second through hole may be different.

For example, the first mask body 320 and the second mask body 330 may be manufactured by a machining process, and the first mask body 320 and the second mask body 330 may be made of metal aluminum. Wherein the plane of the first mask body 320 is a circular hole structure of a 4×4 matrix, and the diameter of the circular hole is 1mm; the plane of the second mask body 330 is a 2/1/2 of 5 round hole structure, and the diameter of the round hole is 2mm. That is, the first through hole includes a circular hole of a 4×4 matrix, the circular hole having a diameter of 1mm; the second through hole comprises 5 round hole structures of 2/1/2, and the diameter of the round hole is 2mm.

It should be understood that, in this step, reference may be made to step 101, and a detailed description thereof will not be repeated here.

302, a first mask body 320 is disposed on a side of the heat dissipation substrate 312 away from the heat generating chip 311.

It should be understood that the content of this step may refer to step 102, and the detailed description is not repeated here.

303, spraying a first layer of metal powder particles 340 on the side of the heat dissipation substrate 312 where the first mask body 320 is disposed.

In this step, a first layer of cold spraying is required until the metal powder (e.g., copper powder) sprayed from the nozzle wraps the first mask body 320, so that the first layer of metal powder particles 340 are deposited on the surface of the first mask body 320 and the first through hole area of the first mask body 320, thereby forming a first porous medium layer.

304, a second mask body 330 is disposed on the top surface of the sprayed first layer of metal powder particles 340.

305, spraying a second layer of metal powder particles 350 on the side, away from the heat dissipation substrate 312, of the second mask body 330.

In this step, a second layer of cold spraying is required until the nozzle sprays metal powder (such as copper powder) to wrap the second mask body 330, so that the second layer of metal powder particles 350 are deposited on the surface of the second mask body 330 and the second through hole region of the second mask body 330, thereby forming a second layer of porous medium layer.

306, disposing a first mask body 320 again on the top surface of the sprayed second layer of metal powder particles 350.

307, spraying third layer metal powder particles 360 on the side of the first mask body 320 away from the heat dissipation substrate 312.

In this step, a third layer of cold spraying is required until the nozzle sprays metal powder (such as copper powder) to wrap the first mask body 330, so that the third layer of metal powder particles 360 are deposited on the surface of the first mask body 320 and the first through hole region of the first mask body 320, thereby forming a third layer of porous medium layer.

It should be noted that, the other content of step 303, step 305, and step 307 may refer to step 103, and the detailed description is not repeated here.

308, after the spraying is finished, removing the first mask body 320 and the second mask body 330 to obtain the processed high-power density device.

In some embodiments, this step may employ an etching process to etch the aluminum Al mask. For example, alkaline sodium hydroxide NaOH and Al may be used to react with the formula: 2al+2h2o+2naoh=2naalo2+3h2 ∈ and etching away the Al mask body, thereby forming a porous structure and improving the surface porosity of the high-power density device.

It should be understood that, in this step, reference may be made to step 104, and a detailed description thereof will not be repeated here.

In the embodiment of the application, the surface of a high-power density device (such as an IGBT) is subjected to secondary processing, namely, a designed mask body (comprising a first mask body and a second mask body) is arranged on the surface of a heat dissipation substrate in advance, powder spraying particles are deposited on a substrate outside the mask body, and then the mask body can be reacted by an etching process, so that the surface of the IGBT device forms a 3D hollow structure, the surface porosity of the IGBT device is increased, and the boiling heat exchange performance can be greatly increased. In addition, the method can be used for setting multiple holes at the hot spot of the IGBT device in a targeted manner, so that the surface heat exchange capacity of the hot spot is improved, and the chip overtemperature risk is small.

Fig. 4 and fig. 5 are schematic structural diagrams of two electronic devices according to an embodiment of the present application. The electronic device 400 in fig. 4 may be an electronic device after the surface treatment in the above steps 101 to 104; the electronic device 500 in fig. 5 may be an electronic device after the surface treatment by the above steps 301 to 308.

As shown in fig. 4, the electronic device 400 may include: the heat-generating chip 410, the heat-dissipating substrate 420 and the first porous medium layer 430, wherein the heat-dissipating substrate 420 is fixedly connected with the heat-generating chip 410; the first porous medium layer 430 is located at a side of the heat dissipation substrate 420 away from the heat generating chip 410, the first porous medium layer 430 may be formed by a cold spraying process and an etching process, and the first porous medium layer 430 has at least one pore 431.

In some embodiments, the pores 431 of the first porous medium layer 430 may be disposed corresponding to the hot spot positions of the heat generating chip 410. The placement of the pores 431 of the first porous medium layer 430 corresponding to the hot spot locations of the heat generating chip 410 can be understood as: the apertures 431 of the first porous medium layer 430 are coincident with the projection of the hot spot of the heat generating chip 410 along the first direction, which is a direction perpendicular to the connection surface of the heat dissipating substrate 420 and the heat generating chip 410.

That is, in the embodiment of the present application, the porous feature can be customized for the hot spot position of the heat generating chip 410, so that the boiling heat exchange performance at the hot spot position can be accelerated, the surface heat exchange capability at the hot spot position can be improved, and the chip overtemperature risk is small.

In some embodiments, the pores 431 of the first porous medium layer 430 may have a maximum dimension of between 0.1 and 2mm. In the embodiment of the application, the size of the pore 431 is limited, so that the excessive or insufficient pore formed on the surface of the electronic device is avoided, and the boiling heat exchange performance of the electronic device is influenced.

As shown in fig. 5, the electronic device 500 may include: the heat-generating chip 510, the heat-dissipating substrate 520 and the multi-layer porous medium layer 530, wherein the heat-dissipating substrate 520 is fixedly connected with the heat-generating chip 510; a plurality of porous dielectric layers 530 are disposed on a side of the heat dissipation substrate 520 remote from the heat generating chip 510. The multi-layer porous medium layer 530 has at least one pore 531, and the multi-layer porous medium layer 530 may include at least a first porous medium layer and a second porous medium layer, where the second porous medium layer is located on a side of the first porous medium layer away from the heat dissipation substrate 520, and the multi-layer porous medium layer 530 may be processed by a cold spraying process and an etching process.

In some embodiments, the porous dielectric layers 530 may have different or identical pore structures.

It should be noted that the second porous medium layer in the multi-layer porous medium layer 530 has similar features to the first porous medium layer 430 in fig. 4, and the detailed description is not repeated here.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A surface processing method of an electronic device, wherein the electronic device includes a heat dissipation substrate and a heat generating chip connected to the heat dissipation substrate, the method comprising:

a first mask body is arranged on one side, far away from the heating chip, of the heat dissipation substrate, and the first mask body is provided with a first through hole;

spraying metal powder on the surface of the first mask body by adopting a cold spraying process, so that the metal powder is deposited on the surface of the first mask body and the first through hole area of the first mask body;

and removing the first mask body to enable the surface of the electronic device to form a pore structure.

2. The method of claim 1, wherein the first mask body is made of metal, the metal mobility of the first mask body is higher than the metal mobility of the sprayed metal powder,

wherein, the removing the first mask body includes:

and etching the first mask body by adopting an etching process, so that a pore structure is formed on the surface of the electronic device.

3. The method of claim 1, wherein the first mask body has a coefficient of thermal expansion greater than a coefficient of thermal expansion of the sprayed metal powder,

wherein, the removing the first mask body includes:

and removing the first mask body through thermal expansion and cold contraction, so that a pore structure is formed on the surface of the electronic device.

4. A method according to any one of claims 1 to 3, wherein the first mask body is disposed at a position corresponding to a hot spot position of the heat generating chip.

5. The method of any one of claims 1 to 4, wherein prior to removing the first mask body, the method further comprises:

a second mask body is arranged on the surface of the first mask body sprayed with the metal powder, and the second mask body is provided with a second through hole;

spraying metal powder on the surface of the second mask body by adopting a cold spraying process, so that the metal powder is deposited on the surface of the second mask body and a second through hole area of the second mask body;

wherein the method further comprises:

and removing the second mask body.

6. The method of claim 5, wherein the method further comprises:

and manufacturing the first mask body and the second mask body through machining, 3D printing or stamping processes.

7. The method of claim 5 or 6, wherein the first mask body and the second mask body have a concave, convex or planar cross-section, and the cross-section is perpendicular to a connection surface of the heat dissipation substrate and the heat-generating chip.

8. A method according to any one of claims 1 to 7, wherein the surface of the electronic device forms pores having a maximum dimension of between 0.1 and 2mm.

9. The method according to any one of claims 1 to 8, wherein the disposing a first mask body on a side of the heat dissipation substrate away from the heat generating chip includes:

and the first mask body is arranged on one side, far away from the heating chip, of the heat dissipation substrate in a positioning tool, free setting or vacuum adsorption mode.

10. An electronic device, comprising:

a heat generating chip;

the heat dissipation substrate is fixedly connected with the heating chip;

the first porous medium layer is positioned on one side of the heat dissipation substrate far away from the heating chip, and is processed through a cold spraying process and an etching process.

11. The electronic device of claim 10, wherein the pores of the first porous dielectric layer are disposed corresponding to the hot spot locations of the heat generating chip.

12. The electronic device of claim 10 or 11, further comprising a second porous dielectric layer on a side of the first porous dielectric layer remote from the heat dissipating substrate, the second porous dielectric layer being processed by a cold spray process and an etching process.

13. The electronic device according to any one of claims 10 to 12, wherein the largest dimension of the pores of the first porous dielectric layer is between 0.1 and 2mm.

14. An electronic device comprising a heat-dissipating substrate and a heat-generating chip connected to the heat-dissipating substrate, wherein a surface of the electronic device is processed by the method of any one of claims 1 to 9.