JP2021177517A - Semiconductor device - Google Patents

Abstract

To provide a semiconductor device in which heat dissipation is improved.SOLUTION: A semiconductor device 150 comprises: a semiconductor element 121; a circuit layer 112 that has the semiconductor element; an insulating substrate 111 on which the circuit layer is provided; a heat dissipation layer 113 that is provided on a surface being opposite to a surface on which the circuit layer of the insulating substrate is provided; fins 115 that are provided on the heat dissipation layer; and resin 114 that covers a junction part between the fins and the heat dissipation layer. The heat dissipation layer has a heat radiation layer 113b that radiates heat as an electromagnetic wave, and the fins are immersed in a coolant 162.SELECTED DRAWING: Figure 2

Description

The present invention relates to a semiconductor device.

In recent years, the electrification and electronic control of power sources for industrial machines and vehicles (for example, automobiles and railroad vehicles) have been progressing more and more in recent years, and the power sources are required to have high output and miniaturization. Along with this, there is an increasing demand for higher power and smaller size for power modules and semiconductor devices.

Since the amount of heat generated during operation increases as the power of the semiconductor device increases, it is necessary to efficiently dissipate and cool the heat generated by the semiconductor elements constituting the semiconductor device. As a method for radiating and cooling a semiconductor element, conventionally, a method in which a heat radiating member such as a heat sink is arranged in the vicinity of the semiconductor element and the radiating member is brought into contact with a refrigerant to radiate and cool the semiconductor element has been generally used. Examples of the refrigerant include water and oil.

Further, with the demand for miniaturization of the entire power source mechanism, close arrangement of the power source and the semiconductor device is required. An example of close placement is integration. The integration of the power source and the semiconductor device puts the semiconductor device in a more severe temperature environment. Therefore, in order to satisfy high heat countermeasures and electrical insulation, it is conceivable to use an oil cooling mechanism for the cooling mechanism of the semiconductor device and the power source main body. This is because the oil can have an insulating property, and the heat generating portion can be directly cooled by using the oil cooling mechanism.

As described above, heat must be efficiently released in order to meet the demand for miniaturization and high power consumption of the entire power source mechanism. It is known that a wavelength-selective heat radiant material is used as a means for efficiently releasing heat from a heat source of an electronic device.

In Patent Document 1, heat radiation in which a large number of microcavities forming a periodic surface fine uneven pattern are two-dimensionally arranged in an electronic device in which a heat generation source is covered with a resin member having a specific infrared transmission wavelength range. It is disclosed that a wavelength-selective thermal radiation material having a surface is arranged between a heat source and a resin member.

Further, Patent Document 2 discloses that the heat sink has a base portion for preventing the opening of the housing and heat radiating fins for efficiently releasing heat inside the housing to the outside of the space.

Japanese Unexamined Patent Publication No. 2010-27831 Japanese Unexamined Patent Publication No. 2019-75415

In Patent Document 1, a wavelength-selective thermal radiation material is used in an electronic device in order to improve the heat dissipation efficiency of the electronic device. However, other heat dissipation forms such as heat convection are not considered, and further improvement in heat dissipation is desired.

In Patent Document 2, heat generated from an electronic component mounted on a substrate is conducted from the substrate to a metal plate via a heat radiating member, and heat conducted to the metal plate is conducted to a heat sink via a screw. , Letting the heat escape. However, other heat dissipation forms such as heat radiation are not considered, and further improvement in heat dissipation is desired.

In Patent Document 1 and Patent Document 2, in order to further improve the heat dissipation property, it is conceivable to directly cool the heat radiating body by using a refrigerant. However, if the material used for the heat-dissipating base material such as Cu continues to be in direct contact with a refrigerant such as oil or water, corrosion occurs due to oxidation of the surface of the base material and impurities such as water contained in the oil. When the base material is corroded, the precipitates generated by the corrosion are mixed with the refrigerant, and the fluidity of the refrigerant such as viscosity changes. As a result, heat dissipation may decrease.

Therefore, an object of the present invention is to provide a semiconductor device having improved heat dissipation.

The semiconductor device according to the present invention for solving the above problems is a semiconductor element, a circuit layer having the semiconductor element, an insulating substrate on which the circuit layer is installed, and a side opposite to the surface on which the circuit layer of the insulating substrate is installed. The heat-dissipating layer includes a heat-dissipating layer, fins provided on the heat-dissipating layer, and a resin that covers a joint between the fins and the heat-dissipating layer. The fins are characterized in that they are immersed in a refrigerant.

According to the present invention, it is possible to provide a semiconductor device having improved heat dissipation.

Circuit body according to the first embodiment Semiconductor device of the first embodiment Surface area of heat dissipation layer Micro uneven structure of thermal radiant zone Infrared absorption spectrum Circuit body according to the second embodiment Semiconductor device of the second embodiment Heat radiator sample used in Experiment 1 Schematic cross-sectional view of the radiator sample in FIG. 8 in the AA'direction.

[First Embodiment]
FIG. 1 is a schematic view of the circuit body 100 according to the first embodiment.

As shown in FIG. 1, the circuit body 100 includes a semiconductor element 121, a circuit layer 112 having the semiconductor element 121, an insulating substrate 111 on which the circuit layer 112 is installed, and the semiconductor element 121 and electricity via the circuit layer 112. First input / output terminal 131 electrically connected, a conductive wire 134 electrically connecting the circuit layer 112 and the semiconductor element, and a second electrically connected to the semiconductor element 121 via the conductive wire 134 and the circuit layer 112. It has an input / output terminal 132 and a gate signal terminal 133 that transmits a gate signal for controlling the semiconductor element 121 via the conductive wire 134 and the circuit layer 112.

As the semiconductor element 121, the conventional semiconductor element may be applied. For example, a rectifying diode, an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Power MOSFET Semiconductor Field Effect Transistor), a MOSGTO thyristor (MOS Gate Turn Off), etc. can be used as appropriate.

The insulating substrate 111 only needs to satisfy the properties required for the power module for power control, and conventional insulating substrates such as ceramic substrates and resin substrates can be appropriately used. It is preferable to select an insulating substrate from the viewpoint of withstand voltage, relative permittivity, and mechanical strength. Further, the thickness of the insulating substrate 111 can be appropriately selected within the range of, for example, 0.1 mm or more and 5 mm or less.

Examples of the ceramic substrate include an alumina (Al ₂ O ₃ ) substrate, an alumina zirconia (Al ₂ O ₃ / ZrO ₂ ) substrate, an aluminum nitride (AlN) substrate, a silicon nitride (SiN) substrate, and the like. Examples of the resin substrate include a phenol resin substrate, an epoxy resin substrate, a polyimide resin substrate, a fluororesin substrate, a bismaleimide triazine resin substrate, and the like on a paper, glass cloth, or composite material as a base material.

Further, as a method for forming the circuit layer 112 and the heat radiating layer 113 on the insulating substrate 111, the conventional method can be appropriately used. For example, it can be integrated by sticking joint or molten metal joining via a joining material 261 such as a metal paste.

The circuit layer 112 may also satisfy the properties required for the power module for power control. The circuit layer configuration is selected from the viewpoints of conductivity, energizing current amount, cost, and the like. For example, an aluminum (Al) circuit layer, a copper (Cu) circuit layer, and a Cu alloy circuit layer can be appropriately used. The thickness of the circuit layer 112 is preferably selected as appropriate within the range of, for example, 0.01 mm or more and 3 mm or less. Further, from the viewpoint of the bondability between the circuit layer 112 and the conductive component, a bonded metal layer may be formed by plating on a part of the surface of the circuit layer 112. Examples of the conductive component include a semiconductor element, an input / output terminal, a gate signal terminal, and the like. Examples of the bonded metal layer include a gold (Au) layer, a silver (Ag) layer, and a nickel (Ni) layer.

The conductive wire 134 may also satisfy the properties required for the power module for power control. The material of the conductive wire 134 is selected from the viewpoints of conductivity, energizing current amount, and cost. For example, Al wire and Cu wire can be appropriately used.

FIG. 2 is a schematic view showing a cross section of the semiconductor device 150 using the circuit body of FIG.

As shown in FIG. 2, the semiconductor device 150 dissipates heat from the circuit body 100 shown in FIG. 1, the heat radiating layer 113 provided on the insulating substrate 111 of the circuit body, the fins 115 joined to the heat radiating layer 113, and heat dissipation. The resin layer 114 that covers the joint between the layer 113 and the fin 115, the refrigerant 162 that immerses the fin, the semiconductor element 121, and the joint between the semiconductor element 121 and the circuit layer 112 are sealed. It has an electric insulating material 141 and a sealing case 142 that covers the electric insulating material 141. The heat radiating layer 113 is provided on a surface opposite to the surface on which the circuit layer of the insulating substrate 111 is formed. Further, the heat radiating layer 113 has a heat radiating base material 113a and a heat radiating layer 113b formed on the surface of the heat radiating base material 113a.

The refrigerant 162 of the present embodiment is, for example, oil or water. Oil has the advantage that it can have electrical insulation and can directly cool the heat dissipation part. As the properties of oil that can be used as a refrigerant, it is sufficient that the properties required for use in electrical and electronic devices such as electrical insulation, heat resistance, flame retardancy, and oxidation resistance can be satisfied. Specific examples thereof include mineral oil, alkylbenzene, polybuden, alkylnaphthalene, alkyldiphenylalkane, ester oil, and silicone oil.

As described above, by covering the joint portion between the heat radiation layer 113 and the fin 115 with the resin layer 114, oxidation and corrosion of the heat radiation base material 113a and the heat radiation layer 113b due to contact with the refrigerant can be suppressed. Further, the protection of the joint portion between the heat radiating layer and the fin by the resin layer also has an effect of suppressing cracks that are likely to occur at the joint portion between the heat radiating base material 113a and the fin 115.

Examples of the material constituting the resin layer 114 include phenol resin, alkyd resin, aminoalkyd resin, urea resin, silicone resin, melamine urea resin, epoxy resin, polyamide resin, polyimide resin, polyamideimide resin, polyurethane resin, polyester resin, and non-polycarbonate resin. Examples thereof include saturated polyester resin, polyesterimide resin, vinyl acetate resin, acrylic resin, rubber chloride resin, vinyl chloride resin, and fluororesin. A combination of two or more of these resin materials may be used. From the viewpoint of heat resistance and oil resistance, epoxy resin, polyamide-imide resin and the like are preferable as the material constituting the resin layer.

From the viewpoint of preventing corrosion of the heat radiating plate and suppressing cracks, the thickness of the resin layer is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

However, since the resin layer 114 has a lower thermal conductivity than the metal material constituting the heat radiating base material 113a and the fin 115, even if the resin layer 114 can suppress the occurrence of oxidation, corrosion, and cracks, the heat radiating property May decrease.

Therefore, in the semiconductor device according to the embodiment of the present invention, a heat radiating layer 113 having a heat radiating layer 113b that radiates heat as an electromagnetic wave transmitted through the resin layer 114 is provided on the surface of the circuit body 100.

It is important that the heat radiating base material 113a has good thermal conductivity, and a material similar to that of the circuit layer 112 can be preferably used. For example, Al, Cu, and Cu alloys are preferable. The thickness of the heat radiating base material 113a, which is an important parameter for suppressing the warp of the circuit body, is preferably the same as or more than the thickness of the circuit layer, and is within the range of 0.01 or more and 3 mm or less. Is preferable. For example, when the thickness of the circuit layer is 0.2 mm, the thickness of the heat radiating base material 113a may be 0.3 mm.

FIG. 3 is a perspective view showing the heat radiating layer 113. Further, FIG. 4 is a diagram showing a microconcavo-convex structure 116 of the heat radiating zone 113b. As shown in FIG. 3, a heat radiating layer 113b having a predetermined microconcavo-convex structure 116 is formed on the surface of the heat radiating base material 113a. It is radiated by adjusting the pitch 118 (the length obtained by combining the length of the convex portion and the length of the concave portion) and the gap 119 (the height of the convex portion or the depth of the concave portion) of the microconcavo-convex structure 116 shown in FIG. It is possible to control the wavelength range of electromagnetic waves. This is because the surface plasmon resonates from the surface of the thermal radiating zone 113b at a specific frequency and emits an electromagnetic wave at the specific frequency, that is, a specific wavelength. When the recess is a cylindrical cavity, the diameter 117 of the cylinder may be adjusted.

Since the resin layer 114 easily transmits infrared rays having a wavelength of 1 μm or more and 8 μm or less, the thermal radiation layer according to the present embodiment preferably emits infrared rays having a wavelength of 1 μm or more and 8 μm or less. FIG. 5 shows an infrared absorption spectrum at each wavelength of the thermal radiant zone according to the embodiment of the present invention. As shown in FIG. 5, it can be seen that the thermal radiation zone absorbs infrared rays having a wavelength of 1 μm or more and 8 μm or less. According to Kirchhoff's law, the emissivity and absorptivity of electromagnetic waves are equal to each other in the local thermal equilibrium state. Therefore, it can be seen from FIG. 5 that the thermal radiation layer emits infrared rays having a wavelength of 1 μm or more and 8 μm or less.

The pitch of the microconcavo-convex structure of the thermal radiation layer is preferably 0.5 μm or more and 10 μm or less, and the gap 119 is preferably in the range of 0.25 μm or more and 10 μm or less. By setting the pitch of the microconcavo-convex structure to 0.5 μm or less and 10 μm or less and the gap of the microconcavo-convex structure to 0.25 μm or more and 10 μm or less, thermal energy can be converted into infrared rays having a wavelength of 1 μm or more and 8 μm or less and radiated. It is more desirable that the thermal radiant zone converts heat energy into infrared rays having a wavelength of 2 μm or more and 6 μm or less and radiates them.

When the microconcavo-convex structure is cylindrical, the diameter 117 of the cylinder is preferably formed smaller than the gap. Further, the diameter 117 is preferably in the range of 0.2 μm or more and 4 μm or less.

Examples of the microconcavo-convex structure 116 include a structure having a columnar or prismatic convex or concave portion. The upper part of the convex portion or the concave portion may have a rounded shape. Specifically, as a structure having a concave portion, a structure in which a cavity is processed on the surface of a metal body, and as a structure having a convex portion, a convex structure such as a pillar is formed on a surface other than the joint portion after joining wires. There is something.

From the viewpoint of heat dissipation, the microconcavo-convex structure 116 is preferably formed on 70% or more of the entire surface of the thermal radiation layer 113b, and more preferably formed on the entire surface of the thermal radiation layer 113b.

When the thermal radiation zone is irradiated with infrared rays having a wavelength of 1 μm or more and 8 μm or less, the radiation spectrum integrated amount is preferably 0.4 or more with respect to the radiation spectrum integrated amount of infrared rays having a wavelength of 1 μm or more and 20 μm or less. Since the infrared radiation spectrum integrated amount of infrared rays having a wavelength of 1 μm or more and 8 μm or less is 0.4 or more with respect to the radiation spectrum integrated amount of infrared rays having a wavelength of 1 μm or more and 20 μm or less, infrared rays having a wavelength of 1 μm or more and 8 μm or less are selectively emitted. can do. As a result, heat can be more transmitted through the resin layer as electromagnetic waves, and the heat dissipation of the semiconductor device can be further improved. Further, the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 8 μm or less with respect to the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 20 μm or less is more preferably 0.6 or more, and particularly preferably 0.8 or more. ..

For example, in the case of a blackbody that does not have a spectrum selection function, the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 8 μm or less is 0.35 with respect to the integrated amount of infrared radiation with a wavelength of 1 μm or more and 20 μm or less, and the spectrum selection function. In the case of a resin having no such effect, the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 8 μm or less is about 0.2 with respect to the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 20 μm or less. Therefore, it is difficult for electromagnetic waves to pass through the resin layer 114, and heat stays in the semiconductor device 150.

The total radiant energy from the heating element surface can be determined by integrating the emission spectrum. This radiation spectrum distribution can be calculated from the emissivity and absorption rate of electromagnetic waves on the surface of a substance measured by a simulation by an electromagnetic field analysis method or a Fourier transform infrared spectrophotometer or the like.

The infrared emission spectrum can be measured by, for example, the following method. The transmittance and reflectance of each wavelength when an electromagnetic wave is incident on the thermal radiant zone are measured by a Fourier transform infrared spectrophotometer (FT-IR). From the obtained transmittance and reflectance, the emissivity of each wavelength is calculated according to Kirchhoff's law (Equation 1).

Emissivity = Absorption rate = 1-Transmittance-Reflectance ... (Equation 1)
The amount of integrated radiation spectrum is calculated from the calculated emissivity.

For the thermal radiation layer 113b, for example, a material such as copper, aluminum, nickel, iron, silver, or gold can be used. From the viewpoint of ease of micromachining in semiconductors, the thermal radiation zone is preferably composed of copper, aluminum, and nickel, among other metals.

As a method for forming the thermal radiation layer 113b, a conventional method can be appropriately used. For example, the microconcavo-convex structure 116 may be formed as a heat radiating layer on the surface of the heat radiating base material 113a by a photolithography method. Further, the microconcavo-convex structure 116 may be formed by a vapor phase film forming method such as vapor deposition, or the microconcavo-convex structure 116 may be formed by adhering metal particles having an average particle size of 1 to 4 μm.

Further, in order to improve heat dissipation, fins 115 are bonded to the heat dissipation base material 113a. By providing the fins 115, not only the surface area of the heat radiating member can be increased to improve the heat radiating efficiency, but also the generation of turbulent flow of the refrigerant can be promoted and the heat radiating efficiency can be improved.

As a method of joining the fins 115 to the heat radiating layer 113, there are a method of joining the fins 115 after forming the microconcavo-convex structure 116, a method of joining the fins 115 to the heat radiating base material 113a, and then forming a microconcavo-convex structure.

Examples of the method for joining the fin 115 to the heat radiating layer include ultrasonic metal joining and solder joining. An ultrasonic bonding method capable of bonding at room temperature after the circuit body 100 is constructed is preferable.

As the material of the fin 115, for example, aluminum (Al), copper (Cu), an alloy containing Al or Cu, or the like can be used. The shape of the fin 115 is preferably, for example, a wire having a diameter of 0.1 mm or more and 1 mm or less, or a ribbon having a width of 0.5 mm or more and 5 mm or less and a thickness of 0.1 mm or more and 0.5 mm or less. Wires and ribbons are generally bonded by ultrasonic bonding. When bonding by ultrasonic bonding, the generation of cracks becomes a problem, so when wire or ribbon-shaped fins are used, the effect of coating the fin bonding portion with a resin layer becomes large.

The electric insulating material 141 may satisfy the properties required for the power module for power control. From the viewpoints of electrical insulation, withstand voltage, arc discharge resistance, and heat resistance, conventional electrical insulating materials can be appropriately used. For example, acrylic resin, unsaturated polyester resin, epoxy resin, silicone gel, electrically insulating gas and the like can be mentioned. When the electrical insulating material 141 has high fluidity, it is better to dispose the sealing case 142. This not only maintains the electrical insulation of the portion where the circuit layer 112 and the semiconductor element 121 are joined by solder bonding or the like, but also has the effect of reinforcing the joint portion and preventing the inflow of the refrigerant.

[Second Embodiment]
FIG. 6 is a schematic view of the circuit body 200 according to the second embodiment. FIG. 7 is a schematic view showing a cross section of a semiconductor device using the power module of FIG.

As shown in FIG. 6, the circuit body 200 is electrically connected to the semiconductor element 221 and the first input / output terminal 231 electrically connected to one surface of the semiconductor element 221 and the other surface of the semiconductor element 221. It has a second input / output terminal 232 connected to. The joint portion between one surface of the semiconductor element 221 and the first input / output terminal 231 and the joint portion between the other surface of the semiconductor element 221 and the second input / output terminal 232 are bonded by a bonding material 261.

A gate signal terminal 233 is electrically connected to the semiconductor element 221 mounted on the circuit body via a conductive wire 234.

As shown in FIG. 7, the semiconductor device 250 is joined to the circuit body 200 shown in FIG. 6, the thermal radiation layer 213b provided with the first input / output terminal 231 and the second input / output terminal 232, and the thermal radiation layer. The fins 215, the resin layer 214 that covers the joints of the fins, the refrigerant 262 in which the fins are immersed, the semiconductor element 221 and the conductive wire 234, and the electrical insulating material 241 that seals the gate signal terminal 233. Be prepared. The thermal radiation layer 213b is provided on a surface opposite to the surface on which the semiconductor elements of the first input terminal and the second input terminal are mounted.

As a structure different from the first embodiment, the first input / output terminal 231 and the second input / output terminal 232 are joined so as to sandwich the semiconductor element 221 from both sides. The first input terminal and the second input terminal also function as a heat radiating base material according to the first embodiment.

As the bonding material 261, solder and metal paste are preferable. A suitable material may be selected according to the joining method.

As the constituent members of the circuit body 200 and the semiconductor device 250 of the second embodiment, the same components as those of the power module 100 and the semiconductor device 150 of the first embodiment can be used.

Hereinafter, the present invention will be described in more detail by various experiments.
[Experiment 1]
Two types of radiator samples 300 were prepared in order to evaluate the effect of the heat radiating base material 312 and the resin layer provided to physically protect the joint portion between the heat radiating base material 312 and the fin 315. FIG. 8 is a schematic view showing an example of the radiator sample, and FIG. 9 is a cross-sectional view of the radiator sample of FIG. 8 when cut at AA'.

The radiator sample 300 uses a SiN substrate having a length of 32 mm, a width of 22 mm, and a thickness of 0.635 mm as the insulating substrate 311. A metal plate 312 is attached, and a Cu metal plate 313 having a length of 30 mm, a width of 22 mm, and a thickness of 0.3 mm is attached on the other surface. Fins 315 having P1 = 2 mm, P2 = 2 mm, and H = 3 mm were formed on a Cu metal plate 312 with an Al wire having a diameter of 0.4 mm by an ultrasonic joining method.

Sample A was prepared by forming a resin layer 314 with a polyamide-imide resin at the joints between the Cu metal plate 312 and the Cu metal plate 312 and the fins 315 of the prepared radiator sample. In sample A, the resin layer 314 was formed so that the maximum thickness was 50 μm. Further, the Cu metal plate 312 of the prepared radiator sample and the sample B in which the resin layer 314 was not formed at the joint between the Cu metal plate 312 and the fin 315 were used as sample B.

The prepared two types of samples A and B were used for two types of tests. In Test 1, two types of samples A and B were immersed in oil at a temperature of 150 ° C. for 240 hours. In Test 2, 5000 cycles of Samples A and B were put into a temperature cycle tank at −40 ° C. × 15 minutes to 175 ° C. × 15 minutes. After the completion of each test, the appearance of the surfaces of the Cu metal plate 312 and the resin layer 314 was observed, and the tensile strength test of the wire was carried out. In the tensile strength test of the wire, 10 joints were arbitrarily selected, the wire was pulled up by a load cell, and the load at the time of breakage was read.

The test results are shown in Table 1.

When the surface of the Cu plate was observed through the resin layer of the sample A on which the resin layer was formed, no discoloration of the surface of the Cu plate was observed before and after the immersion test in oil of Test 1. Further, in the wire tensile strength test, the same strength as the tensile strength of the wire itself before the test was obtained, and the fractured portion was also in the middle of the wire. On the other hand, in the sample B in which the resin layer was not formed, the surface of the Cu plate after the immersion test in oil of Test 1 was oxidized and darkened. Further, in the wire tensile strength test, the joint portion between the Cu plate and the wire broke, and the tensile strength also decreased.

In the temperature cycle test of Test 2, the appearance of Sample A did not change, and the tensile strength was maintained at the same level as before the test. On the other hand, in sample B, the surface of the Cu plate was slightly darkened, and the tensile strength was also lowered.

From the above results, by covering the metal plate and the joint portion between the metal plate and the fin with a resin, it was possible to suppress oxidation and corrosion of the metal plate and suppress breakage of the fin joint portion.

A semiconductor device according to the first embodiment as shown in FIG. 2 was manufactured. As the insulating substrate, an AIN substrate having a length of 50 mm, a width of 50 mm, and a thickness of 0.635 mm was used. A Cu plate of JISC 1020, length 48 mm x width 48 mm x thickness 0.3 mm is attached on one surface of the insulating substrate, and JISC 1020, length 48 mm x width 48 mm x thickness is used as a heat dissipation base material on the other surface. A 0.2 mm Cu plate was prepared.

On the surface of the Cu plate, a thermal radiation layer 113b having a microconcavo-convex structure 116 in which recesses were formed in a columnar shape was formed by using a photolithography method. The size of the microconcavo-convex structure 116 is a diameter of 2 μm × a gap of 2 μm, and an in-plane pitch of the columnar recesses of 4.2 μm. When the emission spectrum emitted from the formed heat radiation layer was calculated by the RCWA (Rigorous Coupled Wave Analysis) method, the integrated amount of infrared radiation spectrum with a wavelength of 1 μm or more and 8 μm or less was integrated with the infrared radiation spectrum with a wavelength of 1 μm or more and 20 μm or less. It was 0.6 relative to the amount.

For the calculation of the emission spectrum, DiffractMOD of RSOFT, which is a commercially available simulation software, was used. For the input data, the conditions of the incident wave, the structural profile, the state of the optical constants of the material, and the mesh width were input. Specifically, the setting of the incident wave was set to give a plane wave in the direction perpendicular to the in-plane. The optical constants were calculated using the database built into the simulation software, assuming that the mesh width in the in-plane direction was 0.05 μm. Since the diameter of the circular opening is 2 μm, it is divided into 40 in the radial direction.

IGBTs and diode elements were prepared as semiconductor elements, and they were bonded onto the circuit layer 112 using a sintered Cu bonding paste. As the conductive wire 314, an Al wire having a diameter of 0.4 mm was used. The semiconductor element 121, the conductive wire 314, and the circuit layer 112 were joined by an ultrasonic joining method. Then, a resin case was attached, and the inside of the case was sealed with a commercially available silicone gel.

Fins 115 were formed on the surface of the Cu plate on which the heat dissipation layer was formed with an Al alloy wire having a diameter of 0.4 mm. The fins 115 were arranged using the symbols defined in FIGS. 8 and 9, and fins having P1 = 2 mm, P2 = 2 mm, and H = 2 mm were formed by an ultrasonic joining method.

After forming the fins 115, the heat radiating base material 113a, the heat radiating layer 113b, and the wire joint were coated with a polyamide-imide resin so that the thickest portion was 50 μm, and a resin layer 114 was formed to manufacture a semiconductor device.

The manufactured semiconductor device was mounted on a temperature control device filled with a commercially available ester-based oil (not shown), and an operation test of the semiconductor device was performed. The oil was circulated at a flow rate of 2 L / min while adjusting the temperature so that the temperature of the oil was 60 ± 5 ° C. Then, the input power was adjusted so that the temperature of the simulated semiconductor element was 150 ± 1 ° C.

In order to compare with the semiconductor device 150 manufactured in Example 1, a semiconductor device in which a heat radiating layer is not formed on the surface of the heat radiating base material was manufactured. Then, the same operation test as in Example 1 was performed.

The effect of improving heat dissipation in the operation test is described by replacing it with the amount of semiconductor power. As a result, the power semiconductor power amount of Example 1 was about 1.3 times the power input amount of the semiconductor device of the comparative example. Since infrared rays with a wavelength of 1 μm or more and 8 μm or less are radiated from the heat radiating layer formed on the surface of the radiation base material of the power semiconductor electric energy, the radiated electromagnetic wave energy is transmitted through the resin coating layer to improve the heat radiating property and reduce the electric energy. I was able to increase it.

The power module and the semiconductor device 250 (see FIGS. 6 and 7) according to the second embodiment were manufactured. An IGBT and a diode element were prepared as the semiconductor element 221 and a Cu plate of JIS C 1020 was prepared as the first input / output terminal 231 and the second input / output terminal 232. The size of the Cu plate is 80 mm in length, 40 mm in width, and 1 mm to 1.5 mm in thickness. A JISC 1020 Cu plate was prepared as the gate signal terminal 233. The size of the Cu plate is 35 mm in length, 5 mm in width, and 0.5 mm in thickness. As the conductive wire 234, JISA 1050 and an Al wire having a diameter of 0.3 mm were prepared.

A thermal radiant zone 213b having a microconcavo-convex structure 116 was formed on the outer surface region of the Cu plate as in Example 1. The formed microconcavo-convex structure 116 had a columnar recess, and had a diameter of 117 of 1.5 μm, a gap of 119 of 1.5 μm, and a pitch of 118 of 3 μm. The radiation spectrum emitted from the formed heat-dissipating layer 213b was calculated by the RCWA (Rigorous Coupled Wave Analysis) method and found to be 0.8 with respect to the integral amount of the infrared radiation spectrum having a wavelength of 1 μm or more and 20 μm or less. The radiation spectrum was calculated in the same manner as in Example 1 except that the structural profile was changed to that described above.

When the semiconductor element is sandwiched between the first input / output terminal 231 and the second input / output terminal 232 so as to be sandwiched from both sides, the surface of the first input / output terminal 231 not forming the heat radiation layer 213b and the semiconductor element 221 The joining method and the joining method between the surface of the second input / output terminal 232 on which the heat radiation layer 213b was not formed and the semiconductor element 221 were performed using a sintered Cu joining paste. The semiconductor element 221, the conductive wire 234, and the gate signal terminal 233 were joined by an ultrasonic joining method.

After that, the first input / output terminal 231, the semiconductor element 221 and the conductive wire 234, the gate signal terminal 233, and the second input / output terminal 232 were sealed with an epoxy resin by a transfer molding method. At this time, the surface of the surface of the first input / output terminal 231 and the second input / output terminal 232 opposite to the surface joined to the semiconductor element 221 was exposed without resin sealing.

Fins 215 were formed from Al alloy wires having a diameter of 0.4 mm on the surfaces of the first input / output terminals 231 and the second input / output terminals 232 on which the heat radiation layer 213b was formed and which were not resin-sealed. The fins 215 were arranged using the symbols defined in FIGS. 8 and 9, and fins having P1 = 2 mm, P2 = 2 mm, and H = 2 mm were formed by an ultrasonic joining method.

After forming the fins 215, the Cu plate, the heat radiating zone 213b, and the wire joint of the first input / output terminal 231 and the second input / output terminal 232 that were not resin-sealed were coated with a polyamide-imide resin (the thickest part was 50 μm). The resin layer 214 was formed, and the semiconductor device 250 was manufactured.

Next, the manufactured semiconductor device 250 was mounted on a container filled with a commercially available ester-based oil (not shown), and an operation test of the semiconductor device was performed. The oil was circulated at a flow rate of 2 L / min while adjusting the temperature so that the temperature of the oil was 60 ± 5 ° C., and the input power was measured while adjusting the temperature of the simulated semiconductor element to be 150 ± 1 ° C.

In order to compare with the semiconductor device 250 manufactured in Example 2, a semiconductor device in which a thermal radiation layer is not formed on the surface of the Cu plate of the first input / output terminal 231 and the second input / output terminal 232 that is not resin-sealed is manufactured. bottom. Then, the same operation test as in Example 1 was performed.

The effect of improving heat dissipation in the operation test is described by replacing it with the amount of semiconductor power. As a result, the amount of semiconductor power of Example 1 was about 1.5 times that of the amount of power input of the semiconductor device of Comparative Example. By radiating infrared rays with a wavelength of 1 μm or more and 8 μm or less from the thermal radiation layer formed on the surface of the radiant base material, the radiated electromagnetic wave energy is transmitted through the resin coating layer, which improves heat dissipation and increases the amount of power. did it.

The present invention is not limited to the above-described examples, and includes various modifications. The above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

100, 200 ... Circuit body 111, 311 ... Insulation substrate 112 ... Circuit layer 113 ... Heat dissipation layer 113a, 312 ... Heat dissipation base material 113b, 213b ... Thermal radiation layers 114, 214, 314 ... Resin layer 115, 215, 315 ... Fin 116 ... Micro concavo-convex structure 117 ... Diameter 118 ... Pitch 119 ... Gap 121, 221 ... Semiconductor element 131, 231 ... 1st input / output terminal 132, 232 ... 2nd input / output terminal 133, 233 ... Gate signal terminal 134, 234 ... Conductive wire 141 ... Electrical insulation 142 ... Sealing case 150, 250 ... Semiconductor device 261 ... Bonding material 162, 262 ... Refrigerator 300 ... Dissipator sample

Claims (6)

With semiconductor elements
The circuit layer having the semiconductor element and
The insulating substrate on which the circuit layer is installed and
A heat radiating layer installed on a surface of the insulating substrate opposite to the surface on which the circuit layer is installed,
The fins provided on the heat dissipation layer and
A resin that covers the joint portion between the fin and the heat radiation layer is provided.
The heat radiation layer has a heat radiation layer that radiates heat as electromagnetic waves.
The fin is a semiconductor device characterized in that it is immersed in a refrigerant. In the semiconductor device according to claim 1,
The heat radiation layer is a semiconductor device characterized in that it emits infrared rays having a wavelength of 1 μm or more and 8 μm or less. In the semiconductor device according to claim 1 or 2.
The thermal radiant zone has a concave structure on the surface and has a concave structure.
A semiconductor device characterized in that the pitch of the concave structure is 0.5 μm or more and 10 μm or less, and the gap of the concave structure is 0.25 μm or more and 10 μm or less. In the semiconductor device according to claim 1 or 2.
The thermal radiant zone has a convex structure on the surface and has a convex structure.
A semiconductor device characterized in that the pitch of the convex structure is 0.5 μm or more and 10 μm or less, and the gap of the convex structure is 0.25 μm or more and 10 μm or less. In the semiconductor device according to claim 1,
A semiconductor device characterized in that the refrigerant is oil. In the semiconductor device according to any one of claims 1 to 5.
With the semiconductor element
A semiconductor device comprising an electrical insulating material that seals a joint portion between the semiconductor element and the circuit layer.

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