Power semiconductor module and power unit

Technical Field

The invention relates to embedded to the power of the electronic device mounting structure of the power semiconductor module.

Background Art

Power semiconductor module through the 1 power semiconductor element to dispose of the few kW of power, so because the power semiconductor element generating heat of the power semiconductor element on the power semiconductor element and the joint to the repeatedly applied under excessive thermal stress, in the joint that is formed by a solder such as cracks are generated. In order to increase the power and power semiconductor element on the semiconductor element of the reliability of the joint, the use of the thermoplastic or thermosetting resin to the module integral mold seal technical. As the use of the power semiconductor module mold seal one way, as shown in Figure 14, has the following power semiconductor module: in the high heat conductivity of the ceramic plate 1 is formed on the surface electrode 2a and the back electrode 2b of the insulating substrate 10 of the surface electrode 2a engages the power semiconductor element 3 and wiring, in order to include the use of the insulating substrate in the form of mold resin 60 to carry out molding.

In such includes an insulating substrate is carried out in the molding of the power semiconductor module, through the structure that carries the 2 group in the inverter circuit usually employ the diode and the switch element of the group of 2in1 structure, can be in the husking wiring, so can reduce inductance, improve electrical characteristics. However, as shown in Figure 15, the insulating substrate 10 of the power semiconductor element is connected with the surface of the surface electrode 2a is divided is patterned at least 2 or more, on the other hand, the back side of the back electrode 2b is not divided, the back side of the surface of the stress balance is destroyed, so the insulating substrate 10 of the warp becomes larger. If the insulating base plate 10 the warping of the large, in lubricating oil for connecting the radiator and the power semiconductor module, in order to ensure the adhesion, the need to have a large load pressing the power semiconductor module and the heat sink. When such excessive load to the radiator through the pressing power semiconductor module, the paired resin 60 with the ceramic plate 1 and the surface electrode 2a is applied between the shear stress, to cause the cracks mold resin, stripping problem.

Against such 2in1 mold seal in the structure of the problem, it is proposed to the insulating substrate is divided into 2 to inhibit warping of a method (Patent document 1).

Patent document 1: Japanese opens especially 2012 - 119618 Bulletin

Content of the invention

With respect to the Patent document 1 of the power semiconductor module, although can inhibit warping of the insulating substrate, but in the power semiconductor element by heating caused by the repeated thermal stress, the stress concentration to the in-mold arranged between the insulating substrate, the insulating base plate in the vicinity of between, produce mold resin and stripping of the ceramic plate. As a result, the presence of the deterioration of the insulation of the creeping of the ceramic plate, the withstand voltage of the power semiconductor module to reduce such problems.

The present invention is to solve the problems as mentioned above of the completed, its purpose is to get a to repeated thermal stress resistance is strong and the high reliability of the power semiconductor module.

The invention relates to a power semiconductor module, in the same configuration on one side of the insulator has a plurality of single-side of the base plate is formed with a surface electrode and in one face forming the back electrode of the insulating substrate and adhered to surface electrodes of the power semiconductor element of the surface of the semiconductor element substrate, and has a pair of abutment of the base plate between the semiconductor element is electrically connected to the wiring member, in order to make the at least one configuration of the plurality of the back electrode all exposed mode, to the semiconductor element substrate through the mold resin and wiring member has molded, wherein die resin between the adjacent insulating substrate, from the back electrode side to the predetermined depth of the resin mold resin not filled in the recess.

According to the present invention, the insulating base plate has a concave recess between, thereby can reduce the opposite polarity stress of the insulating base plate between the mold resin shear stress, damps the pattern making resin and the stripping of the insulating substrate such that had not previously been significant effect.

Description of drawings

Figure 1 is the side cutaway view of shown embodiments of the present invention 1 of the structure of the power semiconductor module.

Figure 2 is the bottom view of in view of the embodiments of the present invention 1 of the bottom surface of the power semiconductor module to observe.

Figure 3 is the side cutaway view of shown embodiments of the present invention 2 of the structure of the power semiconductor module.

Figure 4 is the side cutaway view of shown embodiments of the present invention 3 of the structure of the power semiconductor module.

Figure 5 is the side cutaway view of shown embodiments of the present invention 4 of the structure of the power semiconductor module.

Figure 6 is the side cutaway view of a description of the embodiments of the present invention 4 the effect of the power semiconductor module.

Figure 7 is the side cutaway view of shown embodiments of the present invention 4 of the other structure of the power semiconductor module.

Figure 8 is the bottom view and cutaway view of the observation of the embodiments of the present invention 5 of the bottom surface of the power semiconductor module.

Figure 9 is the bottom view of the observation of the embodiments of the present invention 6 of the bottom surface of the power semiconductor module.

Figure 10 is the bottom view of the observation of the embodiments of the present invention 6 of the bottom surface of the other of the power semiconductor module.

Figure 11 is the bottom view of the observation of the embodiments of the present invention 7 of the bottom surface of the power semiconductor module.

Figure 12 is the side cutaway view of shown embodiments of the present invention 8 of the structure of the power component.

Figure 13 is the chart of describing the function of this invention.

Figure 14 is the side cutaway view of the power semiconductor module shown in the past of the example of a structure.

Figure 15 is the side cutaway view of the power semiconductor module shown in the past to other structures of an example.

Description of the symbols

1: insulator substrate; 2a: surface electrode; 2b: the back electrode; 3: power semiconductor element; 5: wiring member; 6: analog resin; 7: recess; 10: the insulating base plate; 20: semiconductor element substrate; 30: radiator; 70: 2nd recess; 77, 707: fireplace; 100: the power semiconductor module.

Mode of execution

Embodiment 1.

Figure 1 is the cutaway view of shown embodiments of the present invention 1 of the structure of the power semiconductor module. The insulating base plate 10 in, from aluminum nitride formed on the ceramic plate and the base plate of the insulator 1 both sides of the joint formed by copper surface electrode 2a and the back electrode 2b. The insulating substrate 10 is according to the 2 sheet 1 group prepared, each insulating substrate 10 of the surface electrode 2a of the joint as the surface of the Si power semiconductor element 3 of the IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) and FWD (Free Wheeling Diode, the fly-wheel diode). The engaging a power semiconductor element 3 of the insulating substrate 10 known as the semiconductor element substrate 20. As shown in Figure 1, each semiconductor element substrate 20 is disposed on the same surface. Figure 1 is a cutaway view, so as the power semiconductor element 3 only diagram shows a IGBT. In addition, in this embodiment 1 in, in order to Si semiconductor as an example show the power semiconductor element, but the power semiconductor element in the SiC (silicon carbide), GaN (gallium nitride) series material, diamond and other materials also can be applied in a wide band gap semiconductor, the power semiconductor element of the kind without constraints. The wide band gap semiconductor compared with the Si semiconductor, at high temperature action, so if the specialized application of the invention, an effect is large. Through the wiring member 5, to an insulating substrate 10 of the surface electrode 2a and another insulating substrate 10 on the wiring of the IGBT, namely to the semiconductor element substrate is formed by the connection between the electrically inverter 1 phasor of the circuit.

In order to ensure that the insulator substrate 1 of surface, the surface electrode 2a with the wiring member 5 and the insulation between the, through the heat hardening resin or thermoplastic resin such mold resin 6, the semiconductor component to the base plate 20 and the wiring member 5 mold seal carried out together. However, the back electrode 2b from mold resin 6 is exposed. Molding method is filling and sealing molding, transfer molding and the like can be, not restricted to the method. mold seal role of improving the environmental pressure resistance and insulating effect, and also play a role in reducing the thermal stress caused by the repeated power semiconductor element of the upper and lower joint damage to improve the power semiconductor module of the role of the reliability of the action. In this way, form the inverter 1 phasor of the circuit structure is known as the 2in1-type power semiconductor module 100.

In the molded into the 2in1-type power semiconductor module 100 in, mold resin 6 expansion and the insulator of the substrate 1 or the surface electrode 2a of different thermal expansion, so the following problems: when subjected to thermal shock, because of the thermal expansion caused by heat stress, mold resin 6 from the insulator of the substrate 1, the surface electrode 2a stripping. In a typical example, mold resin 6 expansion is of 14 ppm, the insulator of the substrate 1 is 5 ppm, the surface electrode 2a and the back electrode 2b is 17 ppm the left and the right, if the temperature generating Δ 70K changes, then when the insulating substrate with the insulating substrate is filled between the resin of the tractors, in mold resin 6 with the insulator of the substrate 1 or the surface electrode 2a such as between 100 mpa shear stress, cause mold resin 6 stripping or crack the bad state.

Therefore, in the present invention, at the stress concentration of the insulating substrate of the insulating base plate between the mold resin 6 in, forming a filling resin 6 of the recess 7. Figure 2 is the bottom view of observing Figure 1 of the bottom surface of the power semiconductor module. As shown in Figure 2, and the recess is formed by a slit 7. Typically, the recess 7 is formed on the insulating substrate to the ratio of the power semiconductor element engaging the same plane as one deep depth. Figure 13 is the diagram of the invention used for description of the role of the profile of the recess, is shown according to the until the power semiconductor element is connected with the surface until the depth of the standard of a part with the depth of the pair of insulating substrates in the vicinity of the stress that is applied to the relationship between the mold resin. As shown in Figure 13, standardization in the depth of the concave part than 1 small, that the depth of the concave part than the power semiconductor element engaging shallow circumstances, in the ceramic substrate with the recess between the bottom surface of the stress concentration, compared with the not forming the concave recess (depth of the concave part is the standardization of 0) situation, stress increases. If the depth of the concave part is the standardization of 1 or more, with the power semiconductor element is engaging the surface of the same or more than the depth of the concave part, and the recess is formed not to be compared with the situation, can reduce the stress. Namely, at least if the recess 7 not to the depth of the power semiconductor element is connected with the surface of surface electrode 2a on the upper surface of the position, cannot have the effect of stress relaxation. In this way, the recess 7 of the depth required for the back electrode 2b, the insulator of the substrate 1, the surface electrode 2a together of the thickness, i.e. the insulating base plate 10 the depth of more than the thickness of the whole. The recess 7 in the form of method, also can be used by the design of the molds, or on the recess part is provided with metal, fluororesin section without filling mold resin. Although there is still in the resin after a filling through laser processing to form the concave recess of the method, but preferably not in productivity.

According to such structure, the insulating substrate 10 with the and the insulating substrate 10 adjacent to the insulating substrate 10 is formed between the resin not with a filling 6 of the recess 7, thus can reduce the thermal shock of the insulator under the base plate 1 of surface and the surface electrode 2a and mold resin 6 shear stress, inhibiting mold resin 6 stripping. In a typical example, the temperature change is 70K of the cases, the insulating base plate 10 and the adjacent insulating substrate 10 mold resin between 6 with the insulator of the substrate 1 or the surface electrode 2a of the shear stress between the relative to the not forming the concave recess 7 under the condition of 100 mpa, reduced to for example 20 mpa. In this case, mold resin 6 bonding strength exceeds the shear stress, so does not mold resin 6 and insulator of the substrate 1 or the surface electrode 2a of stripping.

Power semiconductor module with the requirement of miniaturization, so a slit-like recess 7 preferably of a narrower width. The recess 7 and the insulating substrate 10 b also in accordance with the miniaturization of the interval of the point of view of the preferably is relatively narrow. Typically, the recess 7 a is the width of the 10 μm - 5 mm, the recess 7 with the insulator of the substrate 1 b is the interval of 10 μm - 5 mm. However, in the interval b is 0 μm, namely the insulator of the substrate 1 in the recess 7 in the case of exposed, also will not damage the effect of the present invention. In order to be removed from the mold after molding of the power semiconductor module, the recess 7 of the side can also be inclined.

In addition, the recess 7 can be a 1 in the slit shape, can also be a 2 row above the slit shape. The recess 7 can be both in the atmosphere, can also be filled in mold resin 6 gel such as resin other than depending resin 6 is made of soft materials. If the recess 7 is filled with the gel and the like, in case of generating mold resin crack, can by gel insulation to reduce the deterioration of the insulating resistance.

By taking into account the stress state is suitably set up the recess 7, and also to obtain the power semiconductor module can reduce the effect of warping. By reducing the warping of the power semiconductor module, the heat radiator and the power of the semiconductor module becomes good adhesion, cooling performance is improved, to improve the reliability of the action.

In addition, by forming the concave recess 7, can reduce the amount of usage of the mold resin. Through the consumption of reduces the mold resin, to obtain low-cost, weight-lightening effect.

Embodiment 2.

Figure 3 is the cutaway view of shown embodiments of the present invention 2 of the structure of the power semiconductor module. As shown in Figure 3, can also become mold resin 6 of the wiring member 5 is arranged in the upper part of the recess portion of the 2nd 70. If such as embodiment 1 only as the adjacent insulating substrate 10 is formed between the recess 7, the existence of the wiring member and the lower part is the stress becomes unbalanced, the power semiconductor module is the warping of the concern. According to the embodiment 2 of the structure, can be through forming a wiring member 5 of the upper part of the recess portion of the 2nd 70, correction formed adjoining the insulating substrate 10 of the recess between the 7 caused by the wiring member 5 in the vicinity of the imbalance of the stress, and can reduce power semiconductor module 100 of the warping.

2nd recess 70 need not be a with the recess 7 of the same shape. In order to eliminate the imbalance of the stress, also can make the 2nd recess 70 the width of the concave recess 7 the width of the. 2nd recess 70 can be a method of forming with the recess 7 the same method can also be different method, a method of forming a pair of concave without constraints.

Embodiment 3.

Figure 4 is the cutaway view of shown embodiments of the present invention 3 of the structure of the power semiconductor module. In the embodiment 1 in, in the power semiconductor is applied to the module under the stress of the situation, because the bottom of the recess is square shaped, so there is stress concentration to the corners other than the mold resin 6 from the bottom surface of the crack generation. In this case, if the form the wiring member 5 from mold resin 6 exposed crack and the surface electrode 2a is exposed out of the crack, is via the recess in the wiring member 5 with the surface of the electrode 2a is formed between the area of the not mold resin, this place into a electric leakage path, the power semiconductor module of the deterioration of the insulating resistance.

In order to avoid this problem, as shown in Figure 4 as, recess 7, 2nd recess 70 also can be the bottom surface of the curved surface shape. If not of the entire bottom surface is a curved surface shape, as long as it is in the bottom surface of the recess and the side of the connecting part is formed with R of the shape of the curved surface of the can. According to such structure, can avoid the side and bottom of the recess of the connecting part generate stress concentration, so can inhibit mold resin cracks of the bottom surface. In addition, the bottom surface of the recess and the side of the connecting part is curved shape of course also can be applied to the structure of the embodiment 1, the following embodiments 4 to 7 of the recess.

Embodiment 4.

Figure 5 is the cutaway view of shown embodiments of the present invention 4 of the structure of the power semiconductor module. In the embodiment 3 in, in the power semiconductor module impose very large stress of circumstances, even in the form of a mold resin of the corner of the bottom surface not stress concentration, the bottom surface of the recess the mold also crack, form the connection wiring member and the surface electrode of the leakage path, the presence of the insulation of the power semiconductor module to reduce the concern.

In order to avoid such problems, as shown in Figure 5, recess 7, 2nd recess 70 also can be the bottom surface of the recess of the fireplace has the further recess 77, fireplace 707 of the wedge shape. According to such structure, even in the mold resin crack of the bottom surface, the bottom surface of the recess as shown in Figure 6, the crack 13 from the fireplace 77 produce, can limit the vertical direction to the insulating substrate that the wiring member 5 surface in the direction. Therefore, will not be from the bottom surface to the surface electrode 2a of the periphery of the crack, can ensure that the wiring member 5 with the surface of the electrode 2a insulation performance between the, avoid the power semiconductor module of the fatal fault.

The bottom surface of the wedge shape can also have a plurality of wedges. In addition, the bottom surface can also be not as a wedge shape, but as shown in Figure 7, in the flat recess in the bottom of the fireplace as a needle-shaped recess 77, as long as they can be fixed from the beginning of the concave bottom of the mold resin crack direction can be the same effect. In addition, with the recess 7 is arranged separately from the 2nd the recess 70 of the case, in order to prevent the insulating substrate extending to the side of the crack, at least in the recess 7 can be set up the fireplace.

Embodiment 5.

Figure 8 (A) is to observe the embodiments of the present invention 5 of the bottom surface of the power semiconductor module of bottom view, Figure 8 (B) Figure 8 (A) of the Department of A - A cutaway view. In embodiment 1 of the power in the semiconductor module, as shown in Figure 2, according to 1 are formed by the slit shape in the recess 7, but in so forming 1 are the concave shape of the slit 7 of the cases, the recess 7 of the part is only provided with the thin mold resin and wiring member of the structure, the bending rigidity of the becomes, exists because of the recess 7 of the bending part of the warping of the power semiconductor module large problems.

Aiming at the problem, as shown in Figure 8, the recess 7 can also be along the periphery of the insulating base plate a plurality of slits configured to the shape of a row. Through the structure of such a structure, not through the slit formed between the recess of the part as the fixer (anchor) function, can inhibit the wiring member bending, reduce the warping of the power semiconductor module. The configuration of the interval also may not be equi-spaced. In addition, as shown in Figure 8 the right A - A profile shown, is not the recess 7 become the anchor of the part 61 is preferably not wiring member 5 position. If it is not in the wiring member 5 of the lower part, even if the anchor parts of the crackle mold resin, also will not form the wiring member 5 and the surface electrode 2a the leakage path, it is not easy to cause the power semiconductor module of the deterioration of the insulating resistance.

In addition, such as embodiment 1 as is the recess 7 is set as 1 are under the condition that the shape of the slit, in the molded, between the mold and the insulating substrate, the mobility of the mold resin variation, so it is easy to form the cavity in the mold (void). If formed in the mould cavity, the damage of the insulating resistance of the power semiconductor module. Aiming at the problem, as shown in Figure 8 into the recess 7 is set as a plurality of slits are configured into a row of the shape of the, mold and the insulating base plate between the improved mold resin filling, not easy to form in the mold cavity. Namely, can realize high insulation resistance of the power semiconductor module.

Embodiment 6.

Figure 9 is the bottom view of the observation of the embodiments of the present invention 6 of the bottom surface of the power semiconductor module. As shown in Figure 9, section can also be a plurality of holes is circular configuration into a row to form the recess 7. Then, as shown in Figure 10, the recess can also be slit 7 end part side face of the circular-arc-shaped. In addition, in the embodiment can also be 5 described in Figure 8 of the side of the end of the slit is set to be circular-arc-shaped. The cross sectional shape of the hole, the end of the circular arc shape of the slit also may not be close to the normal round, hole, slit the side of the end of the shape of the curved surface is not angle can be.

Through such a curved surface or not for the corner of the plane and the curved surface to form the side surface of the recess, the recess is not the side of the corner, so even if the set up the concave recess, the stress can not be centralized whereafter the resin, can inhibit crack in the mold resin.

In addition, through the as shown in Figure 9, Figure 10 pursue to the recessed parts of the side surfaces are not at the corner of the surface, the insulating base plate and the die between the filling mold resin becomes high, can produce the cavity damps the pattern making.

Embodiment 7.

Figure 11 is the bottom view of the observation of the embodiments of the present invention 7 of the bottom surface of the power semiconductor module. The insulating substrate is not limited to 2 sheet, also can be 3 or more cards. For example, also can be formed as shown in Figure 11, in order to 6in1-type power semiconductor module arranging the 6 piece of the insulating substrate, the insulating substrate is formed between a recess 7. The recess 7 and the size of the can also be non-uniform or is not a straight linear, if each of the insulating substrate is different from the shape, is adjacent to the insulating substrate in accordance with the shape of the recess formed between the 7 by way of the mold design.

Through the structure of such a structure, with UVW can output terminal of the three-phase inverter of the power device to carry out the molding part together. Through to having three-phase terminal of the power component together to carry out molding, utilized in-mold wiring reduce the parasitic inductance to improve the electrical characteristics of effect, the use of assembly process can be reduced to reduce the manufacturing cost of the effect.

Embodiment 8.

Figure 12 is the cutaway view of shown embodiments of the present invention 8 of the structure of the power component. The power semiconductor module of the present invention 100 can be as shown in Figure 12, in the back electrode 2b side to separate the contact member 40 and a radiator is set 30 for use as a power component, in order to make the power semiconductor module 100 produced in the hot radiation. Can use a plurality of such power component to apply to railway vehicle, the hybrid vehicle such as the inverter device.

Here, in the power semiconductor module 100 with the radiator 30 between the contact parts of the 40 not by lubricating oil and by the solder and the like under the condition that the rigid body is formed, in the prior art in the power semiconductor module, because the power semiconductor module and the difference between the expansion of the radiator, the power semiconductor module exerts in a big way thermal stress, the insulating substrate and the stripping of the mold resin substantial development.

By aiming at the problem application the structure of this invention, can inhibit the insulating substrate 10 with the insulating substrate 10 between the stripping of the mold resin, crack, can improve the reliability of the power component.

In addition, the adoption of the solder and the like rigid body to engage the power semiconductor module 100 of the back electrode 2b and radiator 30 under the condition of, through the application of the structure, the power semiconductor module to reduce the overall bending rigidity. Therefore, when the switch board to the impact of the power semiconductor module with the radiator at the connection part between the stress load as compared with the past without the concave recess of the structure is reduced. Therefore, by the connecting portion of the damage to the increase of the thermal resistance is suppressed, so that the movements of the power component and also to obtain the effect of improving the reliability.

In addition, the invention can be within the range of its invention freely combined each embodiment, or make each embodiment deform properly, or by slightly its structure element.