JP2020102504A - Power module - Google Patents

Abstract

To provide a power module capable of improving reliability.SOLUTION: According to the present invention, a power module (M) includes a power device (1) having at least a first electrode (11) and a second electrode (12), a first spreader (31) bonded to the first electrode through a first bonding material (41), and a terminal (2) bonded to the second electrode having a bonding area smaller than the first electrode through a second bonding material (42). The first spreader and the terminal are made of copper. The second electrode includes an AlSi layer made of an Al-Si alloy. In the first bonding material, the absolute value of 0.2% proof stress difference between 30°C and 175°C is 10 MPa or less. In the second bonding material, the absolute value of the 0.2% proof stress difference is 20 MPa or less, and the 0.2% proof stress difference is smaller than in the Al-Si alloy in the whole area of 30 to 175°C. According to the power module of the present invention, a crack does not occur in the AlSi layer or the like even under a power cycle of a higher temperature range.SELECTED DRAWING: Figure 2A

Description

The present invention relates to power modules.

A power module having a power device (semiconductor element) such as an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), or a diode is used for a motor driving inverter or the like.

In order to ensure the reliability of the power module, first, it is necessary to efficiently radiate the heat generated during the operation of the power device (also simply referred to as “element”). The following patent documents describe the heat dissipation structure.

JP, 2008-42039, A JP, 2008-103623, A

By the way, in order to further enhance the reliability of the power module, in addition to ensuring the heat dissipation, it is also important to ensure the heat resistance and the durability in the joint portion of the element electrodes that become high temperature. Therefore, conventionally, a joining material having a high melting point and high heat resistance (for example, lead-free solder such as SnAgCu, SnSb) has been used.

However, the power module using such a bonding material has sufficient durability under a cooling/heating cycle (temperature cycle), but has not necessarily sufficient durability under a power cycle. In the cooling/heating cycle, the power module is repeatedly exposed to a high temperature environment and a low temperature environment where the temperature distribution is substantially uniform. In the power cycle, turning on and off the power to the power device is repeated within a short time, and the power module is repeatedly exposed to an environment in which an uneven temperature distribution is generated.

In order to secure durability under a power cycle, a low Young's modulus or low proof stress (normal temperature range) bonding material has also been used. However, in the power module using such a joining material, the upper limit guaranteed temperature of the joining portion temperature (Tj) is limited to a low temperature range (eg, 150° C. or lower).

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power module capable of ensuring reliability under a power cycle even in a high temperature range.

As a result of earnest studies to solve this problem, the present inventor has found that the mechanical characteristics (eg, proof stress) of the first bonding material for bonding the electrodes on the first surface side (back surface side/lower surface side) of the power device depend on temperature. Property and the temperature dependence of the mechanical properties (for example, proof stress) of the second bonding material for bonding the electrodes on the second surface side (front surface side/upper surface side) within a predetermined range. It was newly found that the reliability (durability) in the can be secured up to a higher temperature range. The present invention described below has been completed by developing this discovery.

《Power module》
(1) The present invention provides a power device which is made of a semiconductor and has at least a first electrode on the first surface side and a second electrode on the second surface side, and a first bonding material on the first electrode. A first spreader to be joined, and a terminal joined to the second electrode via a second joining material, the semiconductor being made of silicon or silicon carbide, and the first electrode being more than the second electrode. The second electrode has an AlSi layer made of an aluminum alloy containing silicon (referred to as “Al—Si alloy”), and the first spreader and the terminal are made of copper or a copper alloy. And the absolute value (|Δσ ₁ |) of the difference between the 0.2% proof stress at 30° C. and the 0.2% proof stress at 175° C. is 10 MPa or less. The second bonding material has a 0.2% proof stress lower than that of the Al-Si alloy in the entire range of 30 to 175°C, and has a 0.2% proof stress at 30°C and a 0.2% proof stress at 175°C. The absolute value (|Δσ ₂ |) of the difference is 20 MPa or less.

(2) The power module of the present invention has high durability (reliability) even under a power cycle in a high temperature range (for example, a temperature range in which the upper limit of the element center temperature or the junction temperature is more than 150°C to 175°C or less). ) Can be demonstrated. For example, even in such an environment, cracking of the AlSi layer that constitutes the second electrode is suppressed.

The reason and mechanism for such excellent effects are not always clear. However, the presence or absence of cracks on the second electrode side (particularly the AlSi layer) influences the temperature dependence of the mechanical characteristics (for example, proof stress) of the bonding material, and the first electrode side opposite to the second electrode side. It is an unprecedented finding that it is effective to make the temperature dependence of the mechanical properties of the first bonding material smaller than that of the second bonding material on the second electrode side. The present invention is based on such findings and is epoch-making.

《Others》
Unless otherwise specified, “x to y” in the present specification includes a lower limit value x and an upper limit value y. A range such as “a to b” may be newly established by setting any numerical value included in various numerical values or numerical ranges described in the present specification as a new lower limit value or upper limit value.

It is sectional drawing which shows typically the principal part of the power module of a double-sided cooling structure type. It is an ultrasonic microscope image which observed the 1st electrode surface vicinity after the power cycle test concerning each sample. It is an electricity distribution pattern figure for 1 cycle concerning a power cycle test. It is an optical microscope image which observed the cross section near the 1st joining material after the power cycle test concerning each sample. It is a graph which shows the temperature dependence of the yield strength of each metal used for the joining material.

One or more components arbitrarily selected from the specification may be added to the components of the present invention. The contents described in this specification can be applied not only to the power module of the present invention but also to its manufacturing method. The component relating to “method” can also be the component relating to “object”.

《Power device》
The power device may be a diode, but is mainly a transistor. The transistor includes a first electrode, a second electrode, and a control electrode (third electrode). In the case of the present invention, the first electrode has a larger electrode area (or junction area) than the second electrode, the first electrode is on the first surface side of the transistor, and the second electrode is on the second surface side (first surface). On the opposite side of the side). The transistor may be any of IGBT, MOSFET, thyristor and the like as long as such a condition is satisfied. In the case of an IGBT, for example, the first electrode serves as a collector electrode and the second electrode serves as an emitter electrode. In the case of a MOSFET, for example, the first electrode is a drain electrode and the second electrode is a source electrode. In the case of a thyristor, for example, the first electrode is an anode electrode and the second electrode is a cathode electrode. In any case, the control electrode is usually a gate electrode. Incidentally, the power module of the present invention may include devices (diodes, etc.) other than transistors and control circuits.

The power device is made of a semiconductor (Si or SiC). The p region and the n region in the semiconductor substrate (chip) are formed by, for example, ion implantation. The first electrode and the second electrode are formed by, for example, metal vapor deposition (metallization), heat treatment (annealing), or the like. The control electrode is formed of, for example, an insulating film (oxide film), a polysilicon film, or the like.

The coefficient of thermal expansion (CTE) of such a semiconductor is about 2 to 5, more preferably about 3 to 6 ppm/K. By the way, Si has a CTE of about 3 ppm/K, and SiC has a CTE of about 3.7 ppm/K.

The first electrode and the second electrode (particularly the second electrode) include an AlSi layer made of an aluminum alloy containing silicon (referred to as “Al—Si alloy”). The AlSi layer is generally provided in order to secure the adhesion between the semiconductor and the Ni electrode and to obtain good electrical contact characteristics. Cracks are likely to occur in the AlSi layer due to the non-uniform temperature distribution, CTE mismatch, and the like that occur under the power cycle environment.

The first electrode and the second electrode may have an extremely thin Al layer or Ti layer (about 50 nm to 500 nm) formed under the AlSi layer (on the semiconductor). Further, a Ni layer or the like may be formed on the AlSi layer. The lower Al layer, Ti layer, and the like are provided, for example, to ensure ohmic contact and adhesion. The upper Ni layer or the like is provided, for example, in order to secure the bondability with the bonding material.

《Terminal and spreader》
The first spreader joined to the first electrode and the terminal joined to the second electrode are made of copper (pure copper such as oxygen-free copper) or copper alloy having excellent electrical conductivity and thermal conductivity. These CTEs are usually about 15 to 19 ppm/K. However, a copper alloy having a small CTE (for example, a Cu—W alloy or a Cu—Mo alloy having a CTE of about 4 to 10 ppm/K) may be used. It should be noted that these may be appropriately applied to the second spreader described later.

When the power device is a transistor having a control electrode on the second surface side, the terminal serves as a spacer that secures a space for a bonding wire bonded to the control electrode, for example. The thickness is, for example, about 0.1 mm to 2 mm, and further about 0.5 mm to 1.5 mm. The second spreader is bonded to the second surface side of the terminal via a third bonding material, for example.

The spreader is a heat conducting member that receives heat generated by the power device and radiates the heat to the outside. The spreader is, for example, a lead frame that also serves as a conductive member, a circuit layer of a DBC (Direct Copper Bond) substrate, or the like.

《Bonding material》
(1) A first bonding material used for a bonding portion between the first electrode and the first spreader (referred to as “first bonding portion”) and a bonding portion between the second electrode and the terminal (referred to as “second bonding portion”). Any of the second bonding materials used for is preferably one in which mechanical characteristics (strength, creep resistance, ductility, Young's modulus, etc.) change little with temperature.

The temperature dependence of the mechanical properties of each bonding material is, for example, the difference between the 0.2% proof stress at 30° C. (σ _L ) and the 0.2% proof stress at 175° C. (σ _H ) (Δσ= σ _L −σ _H ) or its absolute value (|Δσ|). In the case of the first bonding material, for example, the absolute value of the 0.2% proof stress difference (|Δσ ₁ |) is preferably 10 MPa or less, more preferably 6 MPa or less. In the case of the second bonding material, for example, the absolute value (|Δσ ₂ |) of the 0.2% proof stress difference may be 20 MPa or less, and further 12 MPa or less. In any case, the 0.2% proof stress difference (absolute value) of the second bonding material on the second electrode (especially AlSi layer) side where cracks are likely to occur is larger than that of the first bonding material on the opposite surface side. It is advisable to reduce the 0.2% proof stress difference (absolute value).

(2) The first joining material may be made of, for example, a composite material in which an aluminum layer and an intermetallic compound layer are laminated. For the aluminum layer, for example, aluminum foil can be used. This aluminum foil may be made of pure aluminum in which the total amount of impurity elements other than Al is 1 mass% or less (less than), for example. Specifically, its purity is preferably 2N to 4N. 2N means a purity of 99%, 3N means a purity of 99.9%, and 4N means a purity of 99.99%. Excessively high-purity aluminum foil is expensive and can have large temperature changes in mechanical properties. If the amount of impurities is excessive, the aluminum layer may have high strength or low ductility, and its stress relaxation property may decrease.

The thickness of the aluminum layer may be, for example, 60 to 95%, or even 75 to 90% of the total thickness of the composite material. Specifically, the aluminum layer has a thickness of, for example, 10 to 500 μm, further 20 to 200 μm. If the thickness is too small, the thermal strain generated in the second electrode (particularly the AlSi layer) is insufficiently reduced. Further, the stress relaxation property and heat fatigue resistance due to the aluminum layer are also insufficient. When the thickness of the aluminum layer is excessively large, it is difficult to reduce the thickness of the power module.

The intermetallic compound layer is, for example, a metal having a melting point higher than that of the low melting point metal (layer) formed by vapor deposition or the like reacting with the high melting point metal (layer) on at least one surface to be joined. An intermetallic compound (IMC) is produced. Such joining by IMC is called solid-liquid interdiffusion joining or simply "SLID (Solid Liquid Interdiffusion) joining". In the present specification, a bonding material (composite material) in which an aluminum layer (Al layer) and an intermetallic compound layer (IMC layer) formed on at least one surface side (usually both surface sides of the aluminum layer) thereof are stacked. ) Is simply referred to as “Al-SLID”.

The combination of the low melting point metal and the high melting point metal that forms the intermetallic compound layer (and thus the composition of the intermetallic compound) is selected in consideration of the heat resistance temperature of the power module, the heating temperature during the bonding process, the thermal expansion coefficient, and the like. It Examples of the low melting point metal include Sn, In, Ga, Pb, Bi, Zn and the like, and alloys thereof. As refractory metals, there are Ni, Cu, Ti, Mo, W, Si, Cr, Mn, Co, Zr, Nb, Ta, Ag, Au, Pt, etc., and alloys thereof.

As an example, Sn (melting point: about 230° C.) may be combined with Ni (melting point: about 1450° C.) or Cu (melting point: about 1085° C.). For example, when the Sn layer and the Ni layer are brought into contact with each other and heated at about 350° C. for about 5 minutes, an intermetallic compound layer made of nickel tin (NiSn/melting point: about 795° C.) is obtained. In this way, a high melting point composite bonding layer can be obtained while suppressing the bonding temperature. Other combinations of high melting point metal/low melting point metal may be Cu/Sn, Ag/Sn, Pt/Sn/, Au/Sn and the like.

The intermetallic compound layer is usually much thinner than the aluminum layer. The thickness of the intermetallic compound layer (one layer) on one side of the aluminum layer is, for example, about 1 to 15 μm, and further about 3 to 10 μm. The total thickness of the intermetallic compound layer with respect to the total thickness of the composite material is, for example, about 5 to 40%, further about 10 to 25%.

Such Al-SLID has stable mechanical properties (0.2% proof stress, etc.) within the above-mentioned temperature range (30 to 175° C.), and its temperature dependence is sufficiently small. Therefore, Al-SLID (composite material) may be used as the first bonding material or the second bonding material. It can be considered that the mechanical properties of Al-SLID substantially depend on the mechanical properties of the aluminum layer that occupies most of them.

(3) As the second bonding material, various materials having relatively low temperature dependence of mechanical properties can be used. For example, in addition to using the Al-SLID described above, a tin-copper solder that has been conventionally used (simply referred to as "SnCu solder") can be used. The SnCu solder is made of, for example, a tin alloy containing Cu: 0.4 to 1.5 mass% and further 0.5 to 1 mass% with the whole being 100 mass%, and the balance being a tin alloy containing Sn and impurities. In addition, as long as the absolute value of the 0.2% proof stress difference (|Δσ ₂ |) described above is within a predetermined range, solder made of an alloy such as Ag or Ni may be used.

(4) Various solders, Al-SLID, or the like can be used for the third joining material that joins the second surface side of the terminal and the second spreader. The temperature distribution between the terminal and the second spreader is lower and the temperature distribution is substantially uniform than that between the power device and the terminal or the first spreader. Therefore, the temperature dependency of the mechanical properties of the third bonding material does not necessarily matter.

Various power modules were manufactured by changing the combination of the first bonding material and the second bonding material. They were subjected to a power cycle test, and it was observed whether or not cracks were generated in the second joint portion (in particular, the AlSi layer of the second electrode), and the durability (reliability) of the power module was evaluated. The present invention will be described in more detail with reference to such specific examples.

<<Outline of power module>>
FIG. 1 is a sectional view schematically showing a double-sided cooling structure type power module M which is an embodiment of the present invention. The power module M includes a transistor 1 which is an IGBT, a terminal 2 which is a spacer, and a first spreader 31 and a second spreader 32 which are lead frames.

The transistor 1 includes an IGBT substrate 10, a first electrode 11 that is a collector electrode thereof, a second electrode 12 that is an emitter electrode thereof, and a control electrode 13 (third electrode) that is a gate electrode thereof.

The first electrode 11 is bonded to the first spreader 31 via the first bonding material 41. The second electrode 12 is bonded to the first surface side of the terminal 2 via the second bonding material 42. The control electrode 13 is joined to the signal terminal 52 by a bonding wire 51. The second surface side of the terminal 2 is joined to the second spreader 32 via the third joining material 43.

Note that FIG. 1 shows, as an example, a case where the first bonding material 41 is an Al-SLID (composite material) including an aluminum layer 413 and intermetallic compound layers 411 and 412 formed on both surface sides thereof. It was

<Power cycle test>
(1) Samples Various power modules M (samples) to be used in the power cycle test were manufactured. First, the substrate 10 of the transistor 1 is composed of a silicon (Si single crystal) chip (12.4 mm×12.4 mm×thickness 135 μm). The electrode surface (bonding surface) of the first electrode 11 is 12.4 mm×12.4 mm (area: 154 mm ² ), and the electrode surface (bonding surface) of the second electrode 12 is 11 mm×10 mm (area: 110 mm ² ).

The first electrode of the transistor 1 is formed by sequentially stacking an AlSi layer (thickness 5 μm), a Ti layer (thickness 250 nm), and a Ni layer (thickness 3 μm) on the silicon lower surface of the substrate 10. The second electrode of the transistor 1 is formed by sequentially stacking an AlSi layer (thickness 5 μm) and a Ni layer (thickness 3 to 5 μm) on the silicon upper surface of the substrate 10. Each layer is formed by sputtering a source metal (target). In the AlSi layer, Si: 1 mass% and Al: the balance of an aluminum alloy (referred to as "Al-1% Si") were used as the raw metal.

An oxygen-free copper (pure copper) foil was used for the terminal 2 (thickness: 1.15 mm) and the spreaders 31, 32 (thickness: 2 mm).

Various bonding materials shown in FIG. 2A were used for the first bonding material 41 and the second bonding material 42. SnCu is composed of Cu: 0.7% by mass, Sn: the balance of tin alloy solder (thickness: 100 μm). SnSb is composed of Sb: 5 mass% and Sn: tin alloy solder (thickness 100 μm) which is the balance. Note that the alloy composition referred to in the present specification is a mass ratio (mass %) to the entire alloy unless otherwise specified.

The Al-SLID is formed by laminating an aluminum layer 413 made of pure aluminum (2N) foil (thickness 100 μm) and intermetallic compound layers 411, 412 (each thickness 5 μm) made of Sn and Ni. The thickness of the aluminum layer is 91% with respect to the entire Al-SLID.

The Al-SLID is a SLID reaction by heating (270° C.) a joining sheet in which Ni and Sn are metallized on both sides of a pure aluminum foil in order and interposed between the surfaces to be joined in which Ni is metallized. Is formed. The above-mentioned SnCu (Sn-0.7 mass% Cu) solder (thickness 150 μm) was used as the third bonding material.

(2) Test The power cycle test was performed by applying the energization pattern shown in FIG. 2B to each sample (power module M) for 50,000 cycles. The energization was turned on and off so that the element center temperature changed within the range of 30° C. (Tj _min ) and 150° C. or 175° C. (Tj _max ). The element center temperature was measured by a temperature sensor using a diode.

<<Observation>>
(1) For each sample, the second bonding portion (near the second bonding material 42) where the second electrode 12 and the terminal 2 (first surface side) are bonded was observed with an ultrasonic microscope. The observed image and the presence/absence of cracks in the second bonding portion (in particular, the AlSi layer of the second electrode 12) are also shown in FIG. 2A.

(2) The cross section of the second joint portion of each sample was observed with an optical microscope. The observed images are shown together in FIG.

<<Evaluation>>
The following can be seen from FIG. 2A. When SnCu solder is used for the first bonding material 41 and the second bonding material 42 as in Sample 11, cracks are observed in the second bonding portion if the upper limit value (Tj _max ) of the element center temperature is up to 150°C. There wasn't. However, even when SnCu solder is used for the first bonding material 41 and the second bonding material 42 as in the sample 12, when the upper limit value (Tj _max ) of the element center temperature reaches 175° C., the second bonding portion is cracked. There has occurred.

Further, as in Sample 2, even when SnSb solder having higher strength (higher melting point) than SnCu solder was used for the first bonding material 41 and the second bonding material 42, cracks occurred in the second bonding portion. Furthermore, as in Sample 4, when the first bonding material 41 was Al-SLID and the second bonding material 42 was SnSb, cracks occurred in the second bonding portion.

On the other hand, when the first bonding material 41 is Al-SLID and the second bonding material 42 is SnCu solder or Al-SLID like Sample 3 or Sample 5, cracks do not occur in the second bonding portion. It was

Further, as can be seen from FIG. 3, in the case of the sample having a crack, it was also found that the AlSi layer of the second electrode 12 had a crack. In addition, when there is no crack in the second bonding portion as in Sample 3, no crack or waviness was observed in the second electrode 12 (particularly the AlSi layer).

<Consideration>
Based on the above results, the presence or absence of cracks (and thus the durability/reliability of the power module) generated in the AlSi layer or the like of the second electrode depends on the difference (combination) between the materials of the first bonding material and the second bonding material. The different reasons are currently inferred as follows.

(1) FIG. 4 shows the temperature dependence of the 0.2% proof stress of each metal material used for the first bonding material 41 and the second bonding material 42. This temperature dependence is data obtained by tensile testing each metal material under the condition of strain rate: 0.01 to 0.06%/sec using a tensile tester having a constant temperature bath. In addition, about Al-SLID, the temperature dependence of 0.2 yield strength concerning Al (2N) which occupies most of it was shown. Incidentally, the 0.2% proof stress is the stress value when the plastic strain after unloading becomes 0.2% on the stress-strain diagram obtained by the tensile test conducted at each temperature.

As is clear from FIG. 4, the 0.2% proof stress of SnSb solder is considerably large at low temperature (25° C.), but sharply decreases at high temperature (200° C.). That is, the mechanical characteristics of SnSb solder are likely to change greatly with temperature (the temperature dependence is large).

On the other hand, the 0.2% proof stress of SnCu solder is not so large at low temperature (25° C.), but its change with temperature is small (temperature dependency is small). Further, Al-SLID (Al(2N)) has a 0.2% proof stress almost unchanged in the range of 25 to 200° C. and has very small temperature dependence.

Further, as is apparent from FIG. 4, when the absolute value (|Δσ|) of the 0.2% proof stress difference between at 30° C. and at 175° C. is seen, |Δσ|=24 MPa (>20 MPa) for SnSb solder. )Met. On the other hand, SnCu solder was |Δσ|=13 MPa (10 MPa<|Δσ|<20 MPa), and Al-SLID was |Δσ|=3 MPa (|Δσ|<10 MPa). Furthermore, SnCu solder and Al-SLID had a 0.2% proof stress smaller than that of Al-1%Si in the entire range of 30 to 175°C.

(2) Under a power cycle, the temperature of the transistor 1 (particularly the substrate 10) becomes nonuniform, and due to this, the thermal stress, deformation, and strain generated in each electrode and each joint are also likely to become nonuniform. Such non-uniformity is considered to be a major factor causing cracks in each electrode (in particular, the AlSi layer of the second electrode). Such a tendency tends to become more prominent as the element temperature (upper limit value) increases.

However, as in the present invention, a bonding material having small temperature dependence of mechanical properties is used for the bonding portion of the power device, and the bonding material on the opposite surface side to the second bonding material on the second electrode side, which is likely to cause cracks. If the temperature dependency of the first bonding material on the side of the first electrode is further reduced, the reason is not clear, but the above-mentioned uneven strain occurring in each bonding portion or each electrode is significantly suppressed. It is thought that

The detailed mechanism is a rabbit, and by adopting the power module of the present invention, it is certain that the durability and reliability thereof can be secured or improved.

M power module 1 transistor 10 substrate 11 first electrode 12 second electrode 13 control electrode 2 terminal 31 first spreader 32 second spreader 41 first bonding material 42 second bonding material 43 third bonding material

Claims (7)

A power device made of a semiconductor, having at least a first electrode on the first surface side and a second electrode on the second surface side;
A first spreader joined to the first electrode via a first joining material;
A terminal joined to the second electrode via a second joining material,
The semiconductor comprises silicon or silicon carbide,
The first electrode has a larger electrode area to be joined than the second electrode,
The second electrode includes an AlSi layer made of an aluminum alloy containing silicon (referred to as “Al—Si alloy”),
The first spreader and the terminal are made of copper or a copper alloy,
The absolute value (|Δσ ₁ |) of the difference between the 0.2% proof stress at 30° C. and the 0.2% proof stress at 175° C. of the first bonding material is 10 MPa or less,
The second bonding material has a 0.2% proof stress lower than that of the Al-Si alloy in the entire range of 30 to 175°C, and has a 0.2% proof stress at 30°C and a 0.2% proof stress at 175°C. A power module whose absolute value (|Δσ ₂ |) is 20 MPa or less. The first bonding material is made of a composite material in which an aluminum layer and an intermetallic compound layer are laminated,
The power module according to claim 1, wherein the second bonding material is made of a tin alloy solder containing copper. The power module according to claim 1, wherein the first bonding material and the second bonding material are made of a composite material in which an aluminum layer and an intermetallic compound layer are laminated. The power module according to claim 2 or 3, wherein the aluminum layer is made of an aluminum foil having a purity of 2N to 4N. The thickness of the said aluminum layer is 60 to 95% with respect to the thickness of the said composite material whole, The power module in any one of Claims 2-4. The power module according to claim 2, wherein the intermetallic compound layer is made of tin and nickel. The power device is a transistor further having a control electrode on the second surface side,
The terminal is a spacer that secures a space for a bonding wire bonded to the control electrode,
The power module according to claim 1, further comprising a second spreader joined to the second surface side of the spacer.