JP6901196B2 - Semiconductor module and manufacturing method of semiconductor module - Google Patents

Description

The present invention relates to a semiconductor module and a method for manufacturing the semiconductor module.

Patent Document 1 describes an electronic device and a method for manufacturing the electronic device. The electronic device includes an electronic component, a mating member that mechanically connects to the electronic component, and a metal conductor that is interposed between the electronic component and the mating member and connects the electronic component and the mating member to each other. The metal conductor is composed of a precious metal such as Ag. The metal conductor has holes, and the holes are impregnated with a reinforcing resin such as polyimide that reinforces the metal conductor. The reinforcing resin fills the pores to reinforce the metal conductor.

Patent Document 2 describes that a connecting layer of a die bonding portion is formed by an adhesive layer composed of Ag and Cu powder having a maximum particle size of 15 μm or more and 200 μm or less. The connecting layer has a structure in which fine pores are evenly dispersed. With this structure, lead-free is realized, reflow resistance is improved, and the reliability of the temperature cycle is ensured.

Known semiconductor modules include a package, a metal base, and a semiconductor die, which is a high-frequency, high-power semiconductor. Eutectic solder materials such as AuSn, AuGe, and AuSi are used for mounting the semiconductor die. The eutectic solder material has good adhesive reliability, but has a problem of high cost because it contains Au. Elements other than semiconductor dies, such as matching circuits or capacitors, generally have front and back electrodes, and these components are also mounted on the base by eutectic solder.

On the other hand, a metal paste may be used for mounting the semiconductor die. As the metal paste, a conductive paste made of a metal powder such as silver, copper or nickel is used. Further, in recent years, wide bandgap semiconductors such as SiC, GaN, GaO and ZnO have been developed. Since the wide bandgap semiconductor has a high withstand voltage, it can operate at a high voltage. Wide bandgap semiconductors have high electron mobility due to a high electric field, resulting in high performance in the high frequency region.

However, when the wide bandgap semiconductor is mounted on the base with a metal paste, ion migration occurs. Ion migration is a phenomenon in which metal ions move in a high humidity or high electric field environment to cause a short circuit.

Japanese Unexamined Patent Publication No. 2012-109636 JP-A-2009-94341

As the above-mentioned metal paste, those containing Ag or Cu and further containing an organic material such as an epoxy resin are known. This metal paste has an advantage that the cost can be suppressed as compared with the one containing Au. However, the semiconductor die may have a large and thin aspect ratio in its planar shape. Therefore, when the semiconductor die is bonded with the above-mentioned metal paste, the reliability of the bonding may be lowered due to the thinness of the semiconductor die. Further, when bonding is performed in a high temperature environment, it is expected that the bonding force will decrease.

In recent years, a sintered metal paste has been developed in which fine metal particles having a diameter of about several tens of μm are sintered at a temperature of 200 ° C. or higher and 400 ° C. or lower. Since this metal paste is hard to melt even at a high temperature after being solidified, it is possible to secure high bonding strength. In this sintered type metal paste, many fine pores are formed inside by sintering the metal fine particles. When the number of pores is small, it becomes difficult to absorb the stress generated due to the difference in thermal expansion between the base and the semiconductor die, which may lead to the destruction of the bonding interface or the semiconductor die due to the thermal cycle.

In order to solve this problem, a method (potting technique) of sealing a semiconductor die with an organic material made of a resin material such as epoxy after bonding is known. In this method, the reliability is improved by the adhesive effect and the stress absorption effect of the organic material, but there may be a problem that the high frequency characteristics are deteriorated due to the dielectric loss of the organic material.

Further, when the sintered body of the metal paste has many pores, the elastic modulus of the sintered body as a whole can be increased, and the stress due to the thermal cycle can be easily absorbed. However, since the density of the sintered body is lowered, there is a concern that the thermal conductivity is lowered due to this. In order to prevent this, it is conceivable to cure the organic material after filling the pores with the organic material, but in this case, since the pores are reduced as described above, there is a problem that the thermal cycle characteristics are deteriorated. It can occur.

An object of the present invention is to provide a semiconductor module capable of suppressing deterioration of thermal cycle characteristics, and a method for manufacturing the semiconductor module.

The semiconductor module according to one embodiment of the present invention includes a metal base, a semiconductor die fixed on the base, a porous metal material interposed between the semiconductor die and the base, a base of a metal granule, and a semiconductor die. The porous metal material has pores impregnated with the organic material, and the surface portion of the organic material impregnated with the pores of the metal granule is solidified. The inside of the organic material impregnated in the pores of the porous metal material is liquid.

The method for manufacturing a semiconductor module according to one embodiment of the present invention includes a step of applying a sintered conductive paste on a metal base and a temperature of 150 ° C. or higher after placing a semiconductor die on the conductive paste. In addition, a step of solidifying the conductive paste by heat treatment at 350 ° C. or lower to form a porous metal material, fixing a semiconductor die with the porous metal material, and a step of impregnating the pores of the porous metal material with an organic material. The inside of the organic material impregnated in the pores of the porous metal material is kept liquid, and the surface portion of the organic material impregnated in the pores of the porous metal material is solidified.

According to the present invention, deterioration of thermal cycle characteristics can be suppressed.

FIG. 1 is a plan view showing a semiconductor module according to an embodiment. FIG. 2 is a diagram showing the surface of the semiconductor die. FIG. 3 is a diagram showing the back surface of the semiconductor die of FIG. FIG. 4 is a plan view showing the semiconductor die of FIG. 2 and the conductive paste. 5 (a) to 5 (f) are views showing a procedure for applying the conductive paste. 6 (a) to 6 (d) are views showing a modified example of the procedure for applying the conductive paste. FIG. 7 is a diagram showing a conductive paste and an organic material between the base and the semiconductor die. FIG. 8 is a cross-sectional view showing the bonding wire and the solidified resin. FIG. 9 is a diagram showing a procedure for forming the solidified resin of FIG. FIG. 10 is a diagram showing a procedure for forming the solidified resin of FIG. FIG. 11 is a diagram showing a procedure for forming the solidified resin of FIG. FIG. 12 is a diagram showing a procedure for forming the solidified resin of FIG. FIG. 13 is a cross-sectional view showing the bonding wire of FIG. 8 and the solidified resin.

Hereinafter, the semiconductor module according to the present invention and the embodiment of the method for manufacturing the semiconductor module will be described with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and duplicate description will be omitted as appropriate.

FIG. 1 is a plan view showing the internal structure of the semiconductor module 1 according to the embodiment. FIG. 1 shows a state in which the lid portion of the semiconductor module 1 is removed. The semiconductor module 1 includes two units U1 and U2, and the configurations of the two units U1 and U2 are the same as each other. The semiconductor module 1 includes a housing 2 on which two units U1 and U2 are mounted.

The internal space of the housing 2 includes a metal base 3 and a pair of ceramic side walls 2c arranged on the base 3. A pair of side walls 2c and a base 3 define an element mounting area A for mounting elements such as an input matching circuit 6, a semiconductor die 7 (semiconductor chip), an output matching circuit 8, and an output capacitor 9. The semiconductor module 1 can be used by covering the side wall 2c with a lid and applying a hermetic seal in a state where the internal space of the housing 2 is replaced with nitrogen.

Each of the two units U1 and U2 includes an input lead 4 fixed to the upper surface of the front wall 2a of the housing 2 and an output lead 5 fixed to the upper surface of the rear wall 2b of the housing 2. Each of the two units U1 and U2 includes an input matching circuit 6, a semiconductor die 7, an output matching circuit 8 and an output capacitor 9 in the element mounting region A surrounded by the side wall 2c. The input matching circuit 6, the semiconductor die 7, the output matching circuit 8 and the output capacitor 9 are provided in this order from the front wall 2a. The semiconductor die 7 includes, for example, a substrate such as Si, SiC, GaN, GaAs, or diamond, and the back surface of the substrate is metal-plated.

The input matching circuit 6, the semiconductor die 7, and the output matching circuit 8 are fixed on the base 3 by the conductive paste. The input matching circuit 6 is mounted on the input side of the semiconductor die 7, and the output matching circuit 8 is mounted on the output side of the semiconductor die 7. Between the input lead 4 and the input matching circuit 6, between the input matching circuit 6 and the semiconductor die 7, between the semiconductor die 7 and the output matching circuit 8, between the output matching circuit 8 and the output capacitor 9, and between the output capacitor 9 and the output. Each of the leads 5 is electrically connected by a plurality of bonding wires.

The base 3 is made of, for example, a laminate of copper, an alloy of copper and molybdenum, an alloy of copper and tungsten, or a copper plate, a molybdenum plate, a tungsten plate, an alloy plate of copper and molybdenum, and an alloy plate of copper and tungsten. The surface of the base material of the base 3 is plated with nickel chromium (dichrome) -gold, nickel-gold, nickel-palladium-gold, silver or nickel, nickel-palladium, or the like. Gold, silver and palladium are plating materials, and NiCr, Ni and the like are seed materials. Adhesion can be improved when the plating material and the seed material are included as compared with the case where the plating material is used alone.

The thickness of the base 3 is, for example, 0.5 to 1.5 mm, and the thickness of the side wall 2c is 0.5 to 1.0 mm. Further, a metal pattern is formed on a part of the upper surfaces of the front wall 2a and the rear wall 2b, and the input lead 4 and the output lead 5 are brazed to the metal pattern, respectively. The input matching circuit 6 and the output matching circuit 8 are, for example, parallel plate type capacitors in which electrodes are provided on the upper surface and the lower surface of the ceramic substrate, respectively.

FIG. 2 is a diagram showing the surface of the semiconductor die 7. FIG. 3 is a diagram showing the back surface of the semiconductor die 7. As shown in FIGS. 2 and 3, the semiconductor die 7 has an elongated rectangular shape. The semiconductor die 7 has a planar shape defined by a pair of short sides 7a and a pair of long sides 7b.

The aspect ratios of the short side 7a and the long side 7b of the semiconductor die 7 are, for example, 1 or more and 10 or less. As an example, the length of the short side 7a of the semiconductor die 7 is 0.5 mm or more and 2.0 mm or less, the length of the long side 7b is 1.0 mm or more and 7.0 mm or less, and the thickness of the semiconductor die 7 is The size is 50 μm or more and 200 μm or less.

The semiconductor die 7 includes a substrate 7c and a source electrode 7d provided on the back surface of the substrate 7c. Further, the semiconductor die 7 includes a plurality of gate electrodes 7e and source vias 7f arranged along the long side 7b, an active region 7g, and a drain electrode 7h on the surface of the substrate 7c. The source electrode 7d is, for example, gold-plated, and the thickness of the source electrode 7d is 5 μm or more and 20 μm or less.

The gate electrode 7e is provided on the opposite side of the drain electrode 7h when viewed from the active region 7g. 7 g of active region contains drain and source finger. The source finger and the back surface source electrode 7d are electrically connected by a source via 7f penetrating the semiconductor die 7. Since the maximum current value that can be passed from the drain to the source is proportional to the gate width, many drain / source fingers are provided in parallel in order to increase the gate width in a high output transistor. As a result, the semiconductor die 7 has a shape that extends elongated along the long side 7b.

The input matching circuit 6 matches the impedance between the input reed 4 and the semiconductor die 7. The output matching circuit 8 matches the impedance between the semiconductor die 7 and the output lead 5. The output matching circuit 8 performs matching so as to obtain desired output, efficiency, and frequency characteristics.

FIG. 4 is a plan view showing the semiconductor die 7 and the conductive paste 10. The conductive paste 10 contains, for example, a minute metal powder, and the metal powder is sintered and cured while being interconnected. The conductive paste 10 is obtained by impregnating a powder of silver, copper, nickel, aluminum, palladium, zinc or tin (diameter 1 nm or more and 200 nm or less) or an alloy thereof in a solvent.

That is, the conductive paste 10 is composed of, for example, the above-mentioned metal powder and a liquid containing a solvent such as a resin. The solvent or the like of the conductive paste 10 volatilizes in a relatively low temperature environment of 150 ° C. or higher and 350 ° C. or lower, whereby the metal powder of the conductive paste 10 solidifies. At this time, since the powders are bonded to each other, the sintered body of the conductive paste 10 has many pores.

The semiconductor die 7 is fixed on the base 3 by the conductive paste 10 interposed between the conductive paste 10 and the base 3. The base 3 has a first region 3a corresponding to the short side 7a of the semiconductor die 7 and a second region 3b corresponding to a region including the center of the pair of long sides 7b. The conductive paste 10 protrudes from the first region 3a in the width direction of the semiconductor die 7 (direction parallel to the short side 7a), and the conductive paste 10 protrudes from the first region 3a (short side 7a). The amount L2 is 10% or more and 50% or less of the length L1 of the short side 7a.

Conventionally, unlike the shape of the conductive paste 10 of the present embodiment, the conductive paste is applied linearly so as to extend to the long side 7b of the semiconductor die 7. When the semiconductor die 7 is placed on the conductive paste applied by this method and the semiconductor die 7 is pressed against the conductive paste until the conductive paste has a specified thickness, the conductive paste becomes the semiconductor die 7 and the base 3. It is crushed and spreads between.

At this time, since the conductive paste has a linear shape along the long side 7b, it is more likely to spread in the longitudinal direction of the semiconductor die 7 than in the width direction of the semiconductor die 7. Therefore, in the longitudinal direction, it easily spreads over the entire longitudinal direction, but in the short direction, the length of expansion is limited, so that the side surface of the short side 7a is crawled up by surface tension to form a fillet. ..

As described above, since the thickness of the semiconductor die 7 is as thin as 50 μm or more and 200 μm or less, the conductive paste crawls up the semiconductor die 7, and when the amount of the conductive paste is large, the conductive paste is conductive on the surface of the semiconductor die 7. The paste may spread. The conductive paste that crawls up the semiconductor die 7 is set to the GND potential, while a high voltage is applied to the drain electrode 7h, so that a high electric field is formed between the drain electrode 7h and the conductive paste and ions are formed. Migration may occur.

On the other hand, when the amount of the conductive paste applied is reduced, the conductive paste does not spread uniformly on the back surface of the semiconductor die 7, and a gap is formed between the semiconductor die 7 and the base 3. If this gap is formed directly below the drain or source finger of the semiconductor die 7, the heat dissipation characteristic of the finger portion is impaired. Therefore, the coating amount of the conductive paste is generally provided with a margin so that the gap is not formed.

Further, when the conductive paste is applied according to the planar shape of the semiconductor die 7, the conductive paste crawls up the side surface of the semiconductor die 7 from the short side 7a as described above. On the other hand, when the conductive paste is applied wider than the width of the semiconductor die 7, it is possible to suppress the creeping up. However, if the coating area of the conductive paste is widened in this way, there is a concern that the housing 2 may be enlarged.

Therefore, in the coating of the conductive paste 10 of the present embodiment, the conductive paste 10 to be applied to the first region 3a including the short side 7a of the semiconductor die 7 is made longer in the width direction of the semiconductor die 7 than the short side 7a. ing. As a result, when the semiconductor die 7 is mounted, the conductive paste 10 near the short side 7a tends to flow along the short side 7a in parallel with the short side 7a, so that the conductive paste 10 easily flows on the side surface of the semiconductor die 7. Crawling can be suppressed. Therefore, since the conductive paste 10 does not come close to the electrodes on the semiconductor die 7, ion migration can be prevented.

Next, the procedure for applying the conductive paste 10 on the base 3 will be described. First, as a means for applying the conductive paste 10, a case where the conductive paste 10 is applied from an air dispenser or a screw dispenser will be described.

The temperature of the conductive paste 10 and the temperature of the base 3 and the temperature of the semiconductor die 7 at the time of coating are, for example, 25 ± 5 ° C. (room temperature). When a screw dispenser is used to apply the conductive paste 10, the conductive paste 10 having a viscosity of 20 Pa · s or more and 30 Pa · s or less is applied at a pressure of 10 kPa or more and 100 kPa or less.

The inner diameter of the nozzle of the dispenser and the width of the coating line of the conductive paste 10 are, for example, 0.5 mm or more and 2.0 mm or less. The coating amount of the conductive paste 10 is adjusted so that the semiconductor die 7 is mounted on the conductive paste 10 and the thickness of the conductive paste 10 is 10 μm or more and 50 μm or less after the conductive paste 10 is cured.

As shown in FIG. 5A, the conductive paste 10 is applied to the first region 3a of the base 3 along one short side 7a of the semiconductor die 7 (conductivity to the first region). Step of applying paste, step of applying sintered conductive paste). At this time, the coating is applied from one end 3c of the first region 3a to the other end 3d at once (a step of coating from one end to the other end of the first region). Further, the coating length of the conductive paste 10 is made longer than that of the first region 3a, and the conductive paste 10 protrudes from both ends of the first region 3a within a range of 10% or more and 50% or less for coating.

As shown in FIG. 5 (b), after the conductive paste 10 is applied to the one first region 3a, the application of the conductive paste 10 is stopped, and the nozzle tip of the dispenser is set to the one first region. It moves to the central portion C1 of the region 3a. Then, as shown in FIG. 5C, the conductive paste 10 is applied along the second region 3b from the central portion C1 (step of applying the conductive paste to the second region). The coating width B is narrower than the width of the semiconductor die 7.

As shown in FIGS. 5 (c) and 5 (d), the coating is stopped (stopping step) in the middle before reaching the other first region 3a. That is, the uncoated region Z of the conductive paste 10 is formed in the second region 3b. After the coating is stopped, the tip of the nozzle of the dispenser is moved to the other first region 3a, and the conductive paste 10 is applied to the other first region 3a.

At this time, as described above, the coating is applied from one end 3e to the other end 3f of the region 3a at once (a step of applying from one end to the other end). Further, the coating length of the conductive paste 10 is made longer than that of the first region 3a, and the conductive paste 10 protrudes from both ends of the first region 3a within a range of 10% or more and 50% or less for coating.

As shown in FIG. 5 (e), after the conductive paste 10 is applied to the other first region 3a, the application of the conductive paste 10 is stopped, and the nozzle tip of the dispenser is set to the other first region 3a. Move to the central part C2 of. Then, as shown in FIG. 5 (f), the conductive paste 10 is applied to the unapplied region Z of the second region 3b from the central portion C2 (the step of applying the paste to the stopped position).

After the coating of the conductive paste 10 to the uncoated region Z is completed, the coating is stopped and the excess paste is cut. Then, the short side 7a is aligned with the first region 3a, the long side 7b is aligned with the second region 3b, and the semiconductor die 7 is mounted on the conductive paste 10 (step of mounting the semiconductor die).

By applying the conductive paste 10 as described above, it is possible to reduce the portion where the coating of the conductive paste 10 overlaps, that is, the portion where the conductive paste 10 is applied twice. Therefore, the shape of the applied conductive paste 10 can be stabilized. Further, the shape of the conductive paste 10 applied to the base 3 is symmetrical, and this makes it possible to suppress the inclination of the semiconductor die 7 when the semiconductor die 7 is mounted. That is, the central portions C1 and C2 on the short sides are all central portions to which the conductive paste 10 is applied at once, and the coating is applied when the conductive paste 10 is applied toward the central portions C2 and C1 of each other. It will be the starting point. Therefore, the coating state of the conductive paste 10 in the central portions C1 and C2 can be made the same.

Next, the method of applying the conductive paste 10 according to the modified example will be described with reference to FIGS. 6 (a) to 6 (d). 6 (a) to 6 (d) show a method of applying the conductive paste 10 in a granular manner using a jet dispenser. When the conductive paste 10 is applied by the jet dispenser, the planar shape of the applied conductive paste 10 is a shape in which the circular conductive paste 10 is continuous.

First, as shown in FIG. 6A, the conductive paste 10 is sequentially applied to one first region 3a of the base 3. Then, the application of the conductive paste 10 is stopped, the tip of the nozzle is moved to the central portion C1 of the region 3a, and as shown in FIG. 6B, the conductive paste 10 is conductive along the second region 3b from the central portion C1. The paste 10 is applied.

After the conductive paste 10 is applied along the second region 3b and reaches the other first region 3a, the application of the conductive paste 10 is stopped, and the nozzle tip is applied to the other first region 3a. Move to the end of. Then, as shown in FIG. 6C, the conductive paste 10 is applied to the other first region 3a. As shown in FIG. 6D, after the application of the conductive paste 10 is completed, the circular conductive paste 10 gradually spreads and becomes one with the adjacent conductive paste 10. The outer edge of the applied conductive paste 10 has a wavy shape.

When the conductive paste 10 is applied with the jet dispenser as described above, since the conductive paste 10 is applied by dropping the granular conductive paste 10, the order of application can be eliminated. That is, when the jet dispenser is used, the order of applying the conductive paste 10 is not limited to the order shown in FIGS. 6 (a) to 6 (d) and can be appropriately changed.

As described above, even when the conductive paste 10 is applied by the jet dispenser, the conductive paste 10 applied to the first region 3a can be made longer in the width direction of the semiconductor die 7 than the short side 7a. it can. Therefore, it is possible to prevent the conductive paste 10 from creeping up on the side surface of the semiconductor die 7, and thus it is possible to prevent ion migration.

After the conductive paste 10 is applied and the semiconductor die 7 is mounted, heat treatment is performed at 150 ° C. or higher and 350 ° C. or lower (250 ° C. as a specific example) in the air or nitrogen atmosphere for about 1 hour to make the conductive paste conductive. The paste 10 is solidified. The solidified conductive paste 10 becomes a porous metal having a large number of pores. The size of the pores is, for example, 1 μm or more and 10 μm or less, which is about the same as the diameter of the metal powder contained in the conductive paste 10 before sintering.

As shown in FIG. 7, in the present embodiment, the pores of the porous metal of the conductive paste 10 are impregnated with the liquid organic material 11 (step of impregnating the organic material). The organic material 11 covers the porous metal exposed from the base 3 and the semiconductor die 7. The organic material 11 is, for example, a solvent volatilization type curing resin.

When the organic material 11 is exposed to an environment having a temperature of 80 ° C. or higher and 120 ° C. or lower for about 1 hour, the solvent contained therein is volatilized and cured. The solvent volatilization type curing resin is, for example, a nitrile rubber-based adhesive or a cyclic polyolefin resin. When the organic material 11 is a solvent volatilization type curing resin, the surface portion 11a of the organic material 11 is cured because the solvent volatilizes, but the inside 11b of the organic material 11 is maintained in a liquid state because it does not volatilize.

By keeping the inside 11b of the organic material 11 impregnated in the pores of the porous metal material in a liquid state, the liquid portion absorbs the stress generated due to the difference in the coefficient of thermal expansion between the base 3 and the semiconductor die 7. Is possible. Therefore, it is possible to avoid a situation in which the bonding interface or the like is destroyed by the thermal cycle. Further, the thermal conductivity can be increased by interposing the organic material 11. Further, since the surface portion 11a of the organic material 11 is cured, the bonding strength of the conductive paste 10 can be increased.

Further, the organic material 11 may be a moisture-curable resin. The moisture-curable resin is a resin that cures when exposed to the atmosphere in a liquid state and undergoes a substitution reaction with moisture in the atmosphere. The moisture-curable resin is, for example, a cyanoacrylate-based resin or a silicone rubber-based resin. The moisture-curable resin existing on the surface side of the porous metal material reacts with moisture in the air and cures, but the moisture-curable resin existing on the inner side does not react with moisture and is maintained in a liquid state.

Even if the organic material 11 is a moisture-curable resin, the internal 11b of the organic material 11 is maintained in a liquid state, so that the liquid portion exerts stress caused by the difference in thermal conductivity between the base 3 and the semiconductor die 7. Absorb. Even if the organic material 11 is a moisture-type curable resin, the same effect as described above can be obtained.

Further, the organic material 11 may be an ultraviolet curable resin. The ultraviolet curable resin is a resin that is cured by irradiating with ultraviolet rays. The ultraviolet curable resin is, for example, an acrylic resin or an epoxy resin. After the pores of the porous metal material are impregnated with the liquid organic material 11, the organic material 11 is irradiated with ultraviolet rays.

By this irradiation with ultraviolet rays, the surface portion 11a of the organic material 11 is exposed to ultraviolet rays and cured, but since the ultraviolet rays do not reach the inside 11b of the organic material 11, the resin in the portion not exposed to the ultraviolet rays is not cured. It remains liquid. Therefore, even if the organic material 11 is an ultraviolet curable resin, the same effect as described above can be obtained.

The procedure for die-bonding the semiconductor die 7 onto the base 3 has been described above. In the die bonding, all the elements mounted inside the housing 2, such as the input matching circuit 6, the output matching circuit 8, and the output capacitor 9, are described. To do. Then, wire bonding is performed between the elements to the input lead 4 and the output lead 5.

FIG. 8 shows the electrical connection between the bonding wire W and the element obtained by wire bonding. In the semiconductor module 1 of the present embodiment, about 70 bonding wires W are connected between the input lead 4 and the input matching circuit 6, and about 16 bonding wires W are connected between the input matching circuit 6 and the semiconductor die 7. About 100 bonding wires W are connected between the semiconductor die 7 and the output matching circuit 8, and about 30 bonding wires W are connected between the output matching circuit 8 and the output capacitor 9, and the output capacitor 9 is connected. About 30 bonding wires W are connected between the output leads 5 and the output leads 5. In FIGS. 8 to 12, each element is appropriately omitted for simplification of the illustration.

In a semiconductor module for high frequency, the physical shape of the wire W is important. The starting position, height, length, and bending shape of the wire W are closely related to impedance matching, and when the wire W is deformed by vibration or impact, the deviation from the design impedance value becomes large, which is desired. The characteristics cannot be obtained. The semiconductor module 1 of the present embodiment has a configuration capable of suppressing deformation of the wire W.

In the semiconductor module 1, the lower portion of each bonding wire W is protected by the solidifying resin R. Since the solidifying resin R mechanically protects the bonding wire W and the connection portion between the bonding wire W and each element, the connection reliability can be improved. Further, when the solidified resin R has moisture resistance, corrosion of the bonding wire W can be suppressed.

The solidified resin R is, for example, a solvent volatilization type resin or a heat-curable resin. The solidified resin R contains 60% or more of a volatile component (organic solvent) and 10% or more and 40% or less of a curing component. The viscosity of the solidified resin R is 1 mPa · s or more and 100 mPa · s or less. Generally, the viscosity of oil (lubricating oil) is about 60 mPa · S, the viscosity of ethanol is about 1 mPa · S, and the viscosity of water is about 0.9 mPa · S, so the viscosity of the solidified resin R is about that of a normal liquid. It is in a sufficiently smooth state.

The bonding wire W is a first bonding wire W1 that connects the first electrode of the semiconductor die 7 and the input matching circuit 6, and a second bonding wire that connects the second electrode of the semiconductor die 7 and the output matching circuit 8. Including W2. The solidifying resin R includes a first solidifying resin R1 that contacts the first bonding wire W1 and a second solidifying resin R2 that contacts the second bonding wire W2.

The solidified resin R exists only in the lower part of each bonding wire W and does not straddle between the plurality of bonding wires W. Each bonding wire W is physically protected by this solidified resin R, and deformation of the wire W due to vibration or impact can be suppressed.

Since the solidified resin R exists only directly under the bonding wire W, the influence on the high frequency performance can be reduced. That is, when the resin is present in the entire cavity S, which is a space surrounded by the base 3 and the side wall 2c, the resin is present in the entire periphery of the plurality of bonding wires W, so that the electricity of the bonding wires W is electric. The effect on the signal transmission characteristics becomes large. On the other hand, in the present embodiment, since the solidified resin R exists only directly under each bonding wire W, the influence on the transmission characteristics is extremely limited.

Next, a method of forming the solidified resin R directly under the bonding wire W will be described. First, as shown in FIG. 9, each element such as the input matching circuit 6, the semiconductor die 7, and the output matching circuit 8 is mounted in the element mounting region A in the cavity S (step of mounting the element), and then each element. Is connected by a bonding wire W (step of performing wire bonding). Then, as shown in FIG. 10, the cavity S surrounded by the side wall 2c of the housing 2 and the base 3 is filled with the liquid solidified resin R.

By filling the cavity S with the solidified resin R, the solidified resin R is aggregated in each bonding wire W by the capillary phenomenon, and also spreads to the corners and gaps of the cavity S. Then, as shown in FIG. 11, the volatile component of the solidified resin R is volatilized. When the solidifying resin R is a solvent volatilization type resin, for example, it is left at room temperature to vaporize the volatile components.

When the solidified resin R is a heat-curable resin, heat treatment is performed to promote volatilization. The viscosity of the solidified resin R increases with volatilization, and as a result, as shown in FIG. 12, the solidified resin R remains only directly under each bonding wire W, and the solidified resin R becomes a solidified resin film (solidified resin). Step of forming).

FIG. 13 shows a cross section of the bonding wire W and the solidified resin R directly below the bonding wire W. As shown in FIG. 13, the solidified resin R thinly covers the bonding wire W and extends from the lower portion of the bonding wire W toward the base 3. The thickness t of the solidified resin R extending from the bonding wire W is smaller than the diameter D of the bonding wire W. As described above, since the thickness t of the solidified resin R is thin, it is possible to reduce the influence on the transmission characteristics while holding the bonding wire W by the solidified resin R.

Although the semiconductor module and the embodiment of the method for manufacturing the semiconductor module have been described above, the present invention is not limited to the above-described embodiment. That is, it is easily recognized by those skilled in the art that various modifications and changes can be made within the scope of the gist of the present invention described in the claims. For example, in the above-described embodiment, the organic material 11 and the solidified resin R have been described, but the material of the organic material 11 and the material of the solidified resin R may be the same as each other or may be different from each other.

1 ... Semiconductor module, 2 ... Housing, 2a ... Front wall, 2b ... Rear wall, 2c ... Side wall, 3 ... Base, 3a ... First region, 3b ... Second region, 3c, 3e ... One end, 3d, 3f ... other end, 4 ... input lead, 5 ... output lead, 6 ... input matching circuit, 7 ... semiconductor die, 7a ... short side, 7b ... long side, 7c ... substrate, 7d ... source electrode, 7e ... gate electrode, 7f ... Source via, 7 g ... Active region, 7h ... Drain electrode, 8 ... Output matching circuit, 9 ... Output capacitor, 10 ... Conductive paste, 11 ... Organic material, A ... Element mounting area, B ... Width, C1, C2 ... Center Part, D ... Diameter, R ... Solidified resin, R1 ... First solidified resin, R2 ... Second solidified resin, S ... Cavity, U1, U2 ... Unit, W ... Bonding wire, W1 ... First bonding wire, W2 ... Second bonding wire.

Claims (6)

With a metal base
With the semiconductor die fixed on the base,
A porous metal material interposed between the semiconductor die and the base,
An organic material that covers the base of the porous metal material and the region exposed from the semiconductor die, and
With
The porous metal material has pores impregnated with the organic material and has pores.
Wherein the surface portion of the organic material impregnated into the pores of the porous metal material is solidified, the interior of said organic material impregnated into the pores of the porous metal material Ri liquid der,
The organic material is a moisture-curable resin.
Semiconductor module. With a metal base
With the semiconductor die fixed on the base,
A porous metal material interposed between the semiconductor die and the base,
An organic material that covers the base of the porous metal material and the region exposed from the semiconductor die, and
With
The porous metal material has pores impregnated with the organic material and has pores.
The surface portion of the organic material impregnated in the pores of the porous metal material is solidified, and the inside of the organic material impregnated in the pores of the porous metal material is liquid.
The organic material is an ultraviolet curable resin.
Semiconductor module. The diameter of the metal powder of the porous metal material before sintering is 1 μm or more and 10 μm or less.
The semiconductor module according to claim 1 or 2. The process of applying a sintered conductive paste on a metal base, and
After placing the semiconductor die on the conductive paste, the conductive paste is solidified by heat treatment at 150 ° C. or higher and 350 ° C. or lower to form a porous metal material, and the semiconductor die is fixed with the porous metal material. Process and
The step of impregnating the pores of the porous metal material with an organic material and
It includes a step of keeping the inside of the organic material impregnated in the pores of the porous metal material in a liquid state and solidifying the surface portion of the organic material impregnated in the pores of the porous metal material.
The organic material is a moisture-curable resin and is
In the solidification step, the surface portion of the organic material is exposed to the atmosphere to solidify the surface portion.
Manufacturing method of semiconductor module. The process of applying a sintered conductive paste on a metal base, and
After placing the semiconductor die on the conductive paste, the conductive paste is solidified by heat treatment at 150 ° C. or higher and 350 ° C. or lower to form a porous metal material, and the semiconductor die is fixed with the porous metal material. Process and
The step of impregnating the pores of the porous metal material with an organic material and
It includes a step of keeping the inside of the organic material impregnated in the pores of the porous metal material in a liquid state and solidifying the surface portion of the organic material impregnated in the pores of the porous metal material.
The organic material is an ultraviolet curable resin and is
In the solidification step, the surface portion of the organic material is exposed to ultraviolet rays to solidify the surface portion.
Manufacturing method of semiconductor module. The process of applying a sintered conductive paste on a metal base, and
After placing the semiconductor die on the conductive paste, the conductive paste is solidified by heat treatment at 150 ° C. or higher and 350 ° C. or lower to form a porous metal material, and the semiconductor die is fixed with the porous metal material. Process and
The step of impregnating the pores of the porous metal material with an organic material and
It includes a step of keeping the inside of the organic material impregnated in the pores of the porous metal material in a liquid state and solidifying the surface portion of the organic material impregnated in the pores of the porous metal material.
The organic material is a solvent volatilization type resin, and is
In the solidification step, the surface portion of the organic material is exposed to an environment having a temperature of 80 ° C. or higher and 120 ° C. or lower to solidify the surface portion.
Manufacturing method of semiconductor module.

Images