JP6858657B2 - Power semiconductor device - Google Patents

Description

The present invention relates to a power semiconductor device having a main terminal and a signal terminal for a current path, and sealing a power semiconductor element and a terminal, and a wire connecting the terminals with a sealing material, and particularly applies solder paste bonding. Regarding power semiconductor devices.

Power semiconductor devices for power conversion are incorporated in various products from transportation equipment to home appliances. In addition, even in products that have not been equipped with semiconductor devices for electric power, the number of cases where they are incorporated is increasing from the viewpoint of power saving and high efficiency. Further miniaturization and improvement of durability are required for these products, and miniaturization and high durability are indispensable conditions for the power semiconductor devices to be mounted.

Power semiconductor devices can operate at higher voltages, higher currents, and higher frequencies than semiconductor devices used in home appliances or computers. On the other hand, power semiconductor devices generate remarkable heat during operation and tend to become hot.

For example, a switching power supply widely used as a power conversion device controls electric power by continuously opening and closing a large current circuit at high speed and repeatedly. By performing such control, the switching power supply generates heat due to the on-resistance of the power semiconductor used as the switching element and the power loss due to the forward voltage drop. Therefore, the solder bondability of the main terminal, which is a large current path of the power semiconductor element, is one of the factors that have a great influence on the durability and reliability of the module product.

In a power module, parts are generally connected by a reflow process, and at that time, a solder paste containing a flux component is used. When the electrode area is large as in the power module, the wett spreadability of the solder paste is not improved even if the temperature at the time of reflow is raised. Therefore, a large amount of solder paste is used to ensure solderability. However, using a large amount of solder paste causes problems such as generation of voids and scattering of flux and solder particles.

As a conventional technique for preventing a defect of a connection terminal in a power module component due to heat, there is a technique of making a hole in the center of a lead electrode surface and using the chimney effect to release gas (void) at the solder joint. (See, for example, Patent Document 1).

JP-A-2007-335767

However, this conventional technique has the following problems. In the component connection terminal for the semiconductor power module described in Patent Document 1 described above, the hole formed in the central portion of the lead electrode surface is for the purpose of discharging the gas of the solder connection portion to the outside. Therefore, the shape of this hole is a reverse taper type in which the opening on the lower surface of the terminal is wide and narrows as it goes upward. Further, in Patent Document 1, solder paste is applied in advance for connecting parts, and the parts are placed on the solder paste.

In this case, the pressing force for placing the component on the solder paste causes extrusion to the periphery of the solder paste that has been applied in advance, and scattering of flux and solder particles. Therefore, the solder paste after melting may come into contact with adjacent chips or wirings, causing an electrical short circuit. Further, there is also a problem that the amount of solder required to obtain sufficient solder meltability does not remain due to the scattering of flux and solder particles.

Further, when solid solder such as plate solder is used, the wettability at the time of solder melting becomes remarkably deteriorated due to the surface oxidation of the solder or the joining member. Therefore, it is necessary to apply a flux agent in advance or to melt the solder in a reducing atmosphere such as formic acid.

On the other hand, when the flux is applied and the solder is melted, a step of cleaning the flux residue is required after the solder is melted due to a problem in reliability. As a result, it is necessary to add work processes or workers, which leads to an increase in cost.

Furthermore, it may not be possible to completely remove the flux residue when arranging small parts or when the structure is complicated. Therefore, there remains a concern about reliability deterioration.

In the case of solder melting due to a formic acid atmosphere, handling of formic acid, management problems, and introduction of an atmosphere forming device dedicated to formic acid are required. Therefore, in the case of solder melting due to a formic acid atmosphere, there is a problem that workability is deteriorated in addition to an increase in cost.

The present invention has been made to solve such a problem, and makes it possible to control the flow of the flux component contained in the solder paste when joining by applying the solder paste, and to reduce the size and weight and to generate a large current. The purpose is to obtain a power semiconductor device that can realize high withstand voltage, low cost, and high reliability.

In the power semiconductor device according to the present invention, a power semiconductor element is mounted on a chip by an Ag sinker, a metal wiring board having a land portion for solder bonding, and a main terminal in which the land portion and one end are electrically connected by solder bonding. It is a power semiconductor device configured with a resin frame frame that covers the periphery of a metal wiring substrate on which a power semiconductor element is mounted, while being incorporated so that the other end of the main terminal protrudes to the outside. The main terminal is provided with an opening for injecting the solder paste containing the flux at one end to be solder-bonded, and a notch for allowing the solder paste to flow out to the outside is provided in a part of the periphery forming the opening. The notch is provided at a position where the solder paste injected into the opening flows out in a direction deviated from the power semiconductor element and the Ag sinker, and enables flow control of the flux component contained in the solder paste. Is.

According to the present invention, by providing an opening having a notch for flowing out the solder paste in a specific direction at one end of the main terminal, even if a large amount of solder paste is applied, the solder paste leaks from the main terminal. We have realized a configuration that can appropriately guide and discharge the solder paste. As a result, when joining with the solder paste applied, the flow of the flux component contained in the solder paste can be controlled, and compactness and weight reduction, large current and high withstand voltage, and low cost and high reliability can be realized. A power semiconductor device can be obtained.

It is a figure which shows the structure of the semiconductor device for electric power which concerns on Embodiment 1 of this invention. It is a figure which shows the specific structure of the upper surface and the cross section of the power semiconductor device which concerns on Embodiment 1 of this invention. It is a figure which showed the upper surface of the main terminal of the power semiconductor device which concerns on Embodiment 1 of this invention, and the cross section along the line III-III. It is a figure which shows typically the outflow of the solder paste in the electric power semiconductor device which concerns on Embodiment 1 of this invention. It is an enlarged view of the cross section of the main terminal of the power semiconductor device which concerns on Embodiment 1 of this invention. This is an example of the shape of the main terminal of the power semiconductor device according to the first embodiment of the present invention. It is a figure which shows the specific structure of the upper surface and the cross section of the power semiconductor device which concerns on Embodiment 2 of this invention. It is a figure which shows typically the outflow of the solder paste in the electric power semiconductor device which concerns on Embodiment 2 of this invention. It is a figure which shows the cross section when the concrete mortar-shaped jig and the jig to be mounted on the main terminal of the power semiconductor device which concerns on Embodiment 3 of this invention are mounted on the main terminal. It is a figure which shows the cross section of the frame frame integrated jig to be mounted on the main terminal of the power semiconductor device which concerns on Embodiment 3 of this invention. It is a flowchart which shows the manufacturing process of the semiconductor device for electric power in Embodiment 4 of this invention.

Hereinafter, preferred embodiments of the power semiconductor device of the present invention will be described with reference to the drawings.

Embodiment 1.
FIG. 1 is a diagram showing a configuration of a power semiconductor device according to a first embodiment of the present invention. The power semiconductor device according to the first embodiment includes a main terminal 5 and a plurality of signal terminals 6 formed so as to project from the resin frame 2 of the module.

The main terminal 5 is a power supply terminal for inputting the main power supply of the power semiconductor device. The main terminal 5 is made of metal and is formed of, for example, an alloy based on copper or stainless steel. The surface of the main terminal 5 may be exposed to the metal of the base material, or at least a part of the surface may be plated.

One end of the signal terminal 6 is formed so as to project from the frame of the module. The signal terminal 6 is a terminal for inputting a signal for controlling the operation of the power semiconductor element 3 from the outside. Like the main terminal 5, the signal terminal 6 is made of metal and is made of an alloy. Further, the signal terminal 6 may be plated on at least a part or the whole surface of the lead.

Frame The frame 2 is injection-moldable and is made of a highly heat-resistant resin. Specific examples of the highly heat-resistant resin include PPS (polyphenylene sulfide) and fluorine-based resins. The frame 2 incorporates a main terminal 5 which is a power supply terminal of a semiconductor element, a signal terminal 6 for operation control, and a terminal for wire bond connection.

The frame 2 is adhered to the substrate 1 on which the semiconductor element is mounted by an adhesive. The adhesive is generally a silicone-based or epoxy-based thermosetting adhesive.

The power semiconductor element 3 includes an upper surface electrode provided on the upper surface of the power semiconductor element 3 and a lower surface electrode provided on the lower surface of the power semiconductor element 3. The bottom electrode of the power semiconductor element 3 is mechanically and electrically connected to the wiring board by being joined to the terminals of the wiring board via a conductive member.

Further, the upper surface electrode of the power semiconductor element 3 is mechanically and electrically connected by being joined to the lower portion of the main terminal 5 via a conductive member. Further, the power semiconductor element 3 is connected to a lead which is an external terminal by a wire. The power semiconductor element 3 has a feature that a current flows in the thickness direction when it is turned on and a current is cut off when it is turned off.

As the material of the power semiconductor element 3, for example, not only Si but also compound semiconductors such as SiC, GaN, and GaAs may be used. Further, a layer capable of soldering, such as a Ni plating layer, may be provided on the surface of the upper surface electrode of the power semiconductor element 3.

A power semiconductor device is a semiconductor device that controls or supplies electric power, and is characterized by handling a large voltage and current. Power semiconductor devices are used for power conversion applications such as voltage conversion, frequency conversion, DC to AC conversion, and AC to DC conversion. Further, semiconductor devices for electric power are used for inverters of home appliances such as air conditioners, refrigerators and washing machines, drive train devices of electric / hybrid automobiles and electric railway vehicles, and illuminance control applications of lighting equipment.

The conductive member is arranged between the upper surface electrode or the wiring board of the power semiconductor element 3 and the main terminal 5, and between the lower surface electrode of the power semiconductor element 3 and the wiring board, respectively. For the conductive member, for example, silver (Ag) paste is used. Ag paste has come to be used in power semiconductor products as one of the die bond materials having excellent high temperature durability and heat dissipation.

The Ag paste is obtained by adding an organic solvent to Ag nanoparticles to form a paste. Ag nanoparticles have high conductivity among metals, and are excellent in heat resistance, high temperature durability and reliability. Further, Ag nanoparticles form a metal bonding layer by sintering the bonding material at a low temperature without melting it by atomizing the metal to nanoscale and increasing the reactivity.

The silicone gel covers the power semiconductor element 3, terminals, wires, and the like, and is used as a sealing material for modules for the purpose of protecting the power semiconductor element from external environmental factors such as light, heat, humidity, and vibration.

In addition, silicone gel has excellent heat and cold resistance peculiar to silicone, is not corrosive, has small shrinkage during curing, and has excellent adhesiveness and adhesion resulting from low crosslink density, and has excellent sealing properties and moisture resistance. It has the property of having sex. Furthermore, silicone gel also has excellent vibration absorption properties, and is widely used as a sealing / protective material and filler.

The wiring board has an insulating layer and a conductor layer, and is joined to the lower surface electrode of the power semiconductor element 3 via a conductive member. The wiring board is a ceramic material wired with copper, aluminum, or the like.

The mortar-shaped jig 12 is made of a heat-resistant material that exceeds the solder melting temperature. Similar to the frame frame 2, PPS (polyphenylene sulfide) or a fluororesin is used for the mortar-shaped jig 12, and ceramics can also be used.

The mortar-shaped jig 12, which is the jig of the present invention, is set in the terminal portion in the solder application step and is removed after the solder application. Alternatively, the mortar-shaped jig 12 can be removed after the solder is melted in the reflow step, or can be sealed with a silicone gel in the subsequent step without being removed as it is.

Further, in the manufacturing process of the frame frame 2, it is possible to integrally mold a shape corresponding to the mortar-shaped jig 12 in advance at the upper position of the main terminal 5 at the time of manufacturing the frame frame by the mold design. In this case, since the frame frame 2 and the mortar shape are integrated, it is not necessary to install the mortar-shaped jig 12 on the main terminal 5 in the process of assembling the power semiconductor element. As a result, it is possible to reduce time and cost by reducing processes and workers.

FIG. 2 is a diagram showing a specific configuration of an upper surface and a cross section of the power semiconductor device according to the first embodiment of the present invention. The substrate 1 used in the power semiconductor device shown in FIG. 2 is composed of an insulating layer such as ceramic, a front conductor layer such as Cu, and a back conductor layer. Then, two power semiconductor elements (IGBT; Integrated Gate Bipolar Transistor and two freewheel diodes) are die-bonded to the surface conductor layer of the substrate 1 by Ag paste.

Further, the back surface of the substrate 1 is joined to a heat sink having an effect of escaping heat generation during operation of a power semiconductor.

The frame frame 2 is adhered to the outer peripheral portion of the chip on the surface of the substrate using a silicone adhesive or the like, and is thermoset. In the frame frame 2, a main terminal 5 serving as a path for a large current for operating a power semiconductor and eight signal terminals 6 for power control project in the vertical direction (Z-axis direction) of the frame frame. ..

Further, in the horizontal direction (XY direction) of the frame, the main terminal 5 for soldering and joining the substrate 1 and the signal terminal 6 for connecting the electrode pad of the power semiconductor element 3 with a wire bond are respectively. It is protruding.

When the frame frame 2 is adhered to the substrate 1 with an adhesive and cured, the land on the substrate 1 and the main terminal 5 protruding from the frame frame 2 are positioned. The bonded and cured power semiconductor device for electric power is set in a jig in the solder coating process after the electrodes on the chip and the terminals on the frame are connected by aluminum wires.

The dispenser unit is moved to the opening on the main terminal 5 and the solder paste is injected. The solder paste can be adjusted so that the optimum coating amount can be obtained by using the air pressure of the dispenser unit, the moving speed of the head portion, and the distance between the dispenser tip portion and the main terminal (GAP) as variables.

By using a residue-free or low-residue type that does not require a cleaning step, the solder paste used can avoid flux coating before soldering and melting in a formic acid reduction atmosphere after soldering. Therefore, by using such a solder paste, it is possible to melt the solder paste in a low oxygen concentration atmosphere in a general-purpose nitrogen reflow device.

FIG. 3 is a view showing the upper surface of the main terminal 5 of the power semiconductor device according to the first embodiment of the present invention and the cross section along the lines III-III.

The main terminal 5 is a terminal for applying solder, which protrudes from the frame frame 2 in the XY direction. This terminal has a so-called tapered shape 10 in which the opening size of the upper surface of the terminal in the Z direction is wider than the opening size of the lower surface.

The case where the solder paste is applied from the upper part of the terminal using the dispenser unit will be described next.

According to the structure of the main terminal 5 according to the present invention, it is possible to prevent the solder paste from remaining on the upper surface of the terminal or leaking from the upper surface of the terminal to the outside of the terminal. Further, the applied solder paste flows to the land portion 15 (see FIG. 2) on the lower surface of the terminal while being melted. Therefore, it is possible to fill the land portion 15 of the substrate 1 and the lower surface and side surface portions of the terminals with an amount of solder paste necessary for forming a good fillet.

FIG. 4 is a diagram schematically showing the outflow of solder paste in the power semiconductor device according to the first embodiment of the present invention. As shown in FIG. 3, the main terminal 5 has a C-shaped cut 9 in which a part of the tip is cut off. In FIG. 4, the cut portion is located between the semiconductor chips 3 mounted side by side on the substrate 1. The solder paste 14 is injected into the main terminal 5.

When the amount of the solder paste 14 is increased when the solder paste 14 is injected by the dispenser unit, the excess solder paste 14 leaks from the opening of the main terminal 5. At this time, the C-shaped cut 9 introduced at the tip of the main terminal 5 induces the flow of the solder paste 14 in the direction perpendicular to the opening, so that the solder paste 14 flows to the semiconductor element (chip) 3 and the Ag sinker area 8. The amount of solder paste 14 to be squeezed can be reduced. That is, by having the C-shaped cut 9, the flow control of the flux component contained in the solder paste 14 can be realized.

Due to this effect, an electrical short circuit due to the leaked solder paste 14 can be prevented. Further, it is possible to avoid the occurrence of Ag ion migration caused by the flux component contained in the solder paste 14 adhering to the Ag sinker area 8, and the reliability of the product can be improved.

FIG. 5 is an enlarged cross section of the main terminal 5 of the power semiconductor device according to the first embodiment of the present invention. In FIG. 5, the cross section of the frame frame 2 is also drawn in an overlapping manner. Similar to FIG. 3, the main terminal 5 has a taper in which the opening of the upper surface of the terminal is wide and becomes narrower toward the lower surface. Further, the outside of the lower surface of the main terminal 5 has a structure having a key portion 11 bent in a key shape (L shape) toward the substrate.

When the solder paste 14 is injected from the dispenser unit, the solder paste 14 flowing on the lower surface of the terminal may be pushed out of the land as it is depending on the viscosity of the solder paste 14 or the distance between the terminal and the substrate land. Therefore, the key portion 11 is provided to serve as a breakwater for preventing the solder paste 14 from being pushed out of the land.

According to the structure of the main terminal 5 according to the first embodiment, it is possible to prevent the solder paste 14 and the flux contained therein from flowing out around the terminals and lands and electrically short-circuiting with the semiconductor element (chip) 3. it can. As a result, it is possible to reduce the size and weight of the module by narrowing the distance between the land for solder bonding and the chip and the wiring. Further, the simple configuration of the main terminal 5 makes it possible to control the flow of the flux component contained in the solder paste, reduce the number of members used, and reduce the cost.

FIG. 6 is a shape example of the main terminal 5 of the power semiconductor device according to the first embodiment of the present invention. This is an example in which a part of the terminal is cut out according to the application in order to guide and control the outflow direction of the solder paste 14.

FIG. 6A illustrates a terminal in which the terminal is cut in the lateral direction. FIG. 6B illustrates a terminal cut at an arbitrary angle. The shape of the terminal is not limited to the shape shown in FIGS. 6 (a) and 6 (b).

Depending on the distance or mutual arrangement between the terminal and the semiconductor element (chip) 3, the land size, the area required for solder bonding, the amount of solder paste applied, etc., the shape of the terminal and the breakage of the terminal are taken into consideration in consideration of the outflow direction of the solder paste. It is possible to design the position and cutting width. As a specific example, FIG. 6 (c) exemplifies a diamond-shaped terminal, and FIG. 6 (d) exemplifies a triangular terminal.

Embodiment 2.
FIG. 7 is a diagram showing a specific configuration of an upper surface and a cross section of the power semiconductor device according to the second embodiment of the present invention. In FIG. 7, one power semiconductor element (IGBT and one freewheel diode) 3 is formed by Ag paste on the surface conductor layer of the substrate 1 composed of an insulating layer such as ceramic, a front conductor layer such as Cu, and a back conductor layer. It is die-bonded. The frame frame 2 is adhered to the outer peripheral portion of the chip on the surface of the substrate using a silicone adhesive or the like, and is thermoset.

In the frame frame 2, a main terminal 5 serving as a path for a large current for operating a power semiconductor and five signal terminals 6 for power control project in the vertical direction (Z-axis direction) of the frame frame 2. There is. Further, in the horizontal direction (XY direction) of the frame frame 2, the main terminal 5 for soldering and joining with the substrate 1 and the signal terminal 6 for connecting to the electrode pad of the power semiconductor element 3 by wire bond are provided. Each is prominent.

After the frame frame 2 is adhered to the substrate 1 with an adhesive and cured, the chip electrode and the terminal on the frame are connected with an aluminum wire. Next, the solder paste 14 is injected into the terminal opening with the dispenser unit. By using a residue-free or low-residue type that does not require a cleaning step, the solder paste 14 can avoid flux coating and melting in a formic acid reduction atmosphere. Therefore, by using such a solder paste 14, it is possible to melt the solder paste 14 in a low oxygen concentration atmosphere in a general-purpose nitrogen reflow device.

FIG. 8 is a diagram schematically showing the outflow of the solder paste 14 in the power semiconductor device according to the second embodiment of the present invention. The main terminal 5 has a shape in which the lateral side on one side of the terminal is cut out. When the amount of the solder paste 14 increases, the solder paste 14 leaking from the opening of the terminal is guided to flow out in the direction perpendicular to the cut of the terminal, and heads for the semiconductor element (chip) 3 and the Ag sinker area 8. The cuts in the main terminals are arranged so that there is no such thing.

As a result, it is possible to prevent a short circuit between the solder paste that has flowed out and the chip. That is, in the Ag sinker area 8, it is possible to avoid the occurrence of Ag ion migration caused by the adhesion of the flux component contained in the solder paste and improve the reliability of the product.

Embodiment 3.
FIG. 9 is a diagram showing a cross section of a specific mortar-shaped jig 12 and a jig mounted on the main terminal 5 of the power semiconductor device according to the third embodiment of the present invention. .. The mortar-shaped jig 12 in the third embodiment is made of an injection-moldable resin such as PPS (polyphenylene sulfide) made of the same material as the frame frame 2.

Before applying the solder paste 14 from the upper part of the terminal by the dispenser unit, the solder paste 14 is applied after the mortar-shaped jig 12 is mechanically controlled or manually positioned and installed on the upper part of the terminal.

Normally, in order to inject the solder paste 14 into the terminal opening with the dispenser unit and fill the solder paste 14 in the gap between the board land portion 15 and the terminal, a number of nozzles (or needles) at the tip of the dispenser head are placed on the upper surface of the terminal. Positioning accuracy close to a distance of tens to hundreds of microns is required.

However, assuming a mass production process, the relative positions of the nozzle tip and the terminal opening of the dispenser unit vary depending on the member tolerance, assembly tolerance, and transport positioning accuracy of the power semiconductor device.

Therefore, in the second embodiment, the mortar-shaped jig 12 is used so as not to be affected by the variation in the positioning accuracy between the nozzle tip and the terminal opening in the mass production process. Specifically, the mortar-shaped jig 12 is installed on the upper surface of the terminal, and the tip of the nozzle for injecting the solder paste is arranged in the opening of the mortar-shaped jig 12. Here, as shown in FIG. 9, the mortar-shaped jig 12 is formed in a shape such that the cross-sectional area of the opening of the mortar-shaped jig 12 is larger than the cross-sectional area of the upper surface opening of the main terminal 5. ing.

By using the mortar-shaped jig 12 having such a shape, the positioning accuracy of the nozzle at the tip of the dispenser head is relaxed, sagging and leakage during solder paste injection are prevented, and the solder paste is included in the chips and wiring. It is possible to prevent electrical short-circuiting due to the flux applied.

FIG. 10 is a diagram showing a cross section of a frame-integrated jig 13 mounted on the main terminal 5 of the power semiconductor device according to the third embodiment of the present invention. Unlike FIG. 9, the frame-integrated jig 13 shown in FIG. 10 has a mortar-shaped jig 12 integrally formed with a resin frame frame due to the mold design. As a result, the alignment mechanism between the frame frame 2 and the mortar-shaped jig 13 is unnecessary.

Frame The frame 2 is made of, for example, a resin such as PPS (polyphenylene sulfide). Therefore, by designing a mold having a mortar-shaped portion and using the mold having a mortar-shaped portion in the manufacturing process of the frame frame 2, the frame-frame integrated jig 13 can be injection-molded. As a result, product quality and yield are stable, and mass production is possible without high cost.

The mortar-shaped jig 13 according to the third embodiment can relax the positioning accuracy of the dispenser unit when the solder paste is applied from the upper part of the terminal by the dispenser unit. As a result, it is possible to suppress dripping, leakage, protrusion, etc. of the solder paste due to the relative positional deviation between the terminal and the dispenser unit, and to apply the required amount of solder paste to the gap between the terminal opening, the bottom of the terminal, and the board land. It becomes.

Furthermore, in order to form sufficient fillets and ensure good meltability of the solder paste, even if a large amount of solder paste is applied, the solder paste leaks to the chips and wiring parts, and is electrically operated by the solder bridge. It is possible to prevent product quality defects due to short circuits and the like.

The heat-resistant mortar-shaped jig can be recycled by removing it after applying the solder paste or after melting the solder paste in the reflow process and re-installing it in a subsequent module. However, if it is judged that the cost will be high in consideration of manpower and equipment for removing and re-installing the heat-resistant jig, it will flow to the subsequent process with the heat-resistant jig attached, and the semiconductor element or terminal , It is also possible to fill the heat-resistant jig with silicone gel together with the wire.

Embodiment 4.
In the fourth embodiment, a series of manufacturing processes of the power semiconductor device according to the present invention will be specifically described with reference to a flowchart. FIG. 11 is a flowchart showing a manufacturing process of the power semiconductor device according to the fourth embodiment of the present invention.

First, Ag paste is printed on the ceramic substrate (board 1) (step S1101), and the power semiconductor element 3 (chip 3) is die-bonded (step S1102).

Next, an epoxy adhesive is applied to the back surface of the frame frame 2, the substrate 1 and the frame frame 2 are overlapped and assembled, and then the substrate 1 and the frame frame 2 are cured in a curing furnace (step S1103).

Next, the electrode (pad) of the chip 3 and the electrode terminal on the surface of the frame 2 are connected by a wire bond with an aluminum wire (step S1104).

Next, the solder paste 14 is applied to the soldered portion provided on the main terminal 5 where the main terminal lead 4 protrudes from the frame frame 2, and the solder is melted and cooled in a low oxygen concentration atmosphere in the reflow process. , The main terminal 5 and the substrate 1 are joined (step S1105).

In this step, as described in the first to third embodiments above, a main terminal 5 having an opening having a notch for flowing out the solder paste 14 in a specific direction is applied at one end. By applying such a main terminal 5, even if a large amount of solder paste 14 is applied, the solder paste 14 leaking from the main terminal 5 can be appropriately guided and discharged, and the flux component contained in the solder paste 14 can be appropriately induced and discharged. Flow control is possible.

Next, solder is placed on the heat sink, and a plurality of power semiconductor devices are placed on the solder. In addition, solder is placed on the electrodes on the chip of the power semiconductor device, leads (metal parts similar to terminals) are installed on the electrodes, melted and cooled in the reflow process, and the leads are assembled by solder bonding. (Step S1106).

Next, the gel is injected into the frame 2 with a silicone-based gel, and the gel is cured in a curing furnace (step S1107).

Next, the support is attached and the main terminals are TIG (Tungsten Inert Gas) welded (step S1108), and the entire inside of the support on which the power semiconductor device is mounted is gel-sealed with silicone gel (step S1109).

After gel sealing, a cooling pipe is press-fitted (step S1110) and the characteristics are inspected (step S1111).

Although not described in this assembly process flow, the quality inspection process such as visual inspection, ultrasonic flaw detection inspection (SAT / C-SAM), X-ray inspection, electrical characteristic inspection, or reduction / cleaning process is a process. It shall be carried out at a predetermined timing in the middle of the flow.

Although the preferred embodiment has been described in detail above, it is not limited to the above-described embodiment, and various modifications and substitutions are made to the above-described embodiment without departing from the scope of the claims. Can be added.

1 board, 2 frame frame, 3 power semiconductor element (semiconductor chip), 4 main terminal lead, 5 main terminal (soldered part), 6 signal terminal, 7 positioning pin, 8 Ag sinker area, 9 terminal notch, 10 Tapered part, 11 key (¬) part, 12 mortar-shaped jig, 13 frame-integrated mortar-shaped jig, 14 solder paste, 15 land part.

Claims (5)

A metal wiring board on which a power semiconductor element is mounted by an Ag sinker and has a land portion for solder bonding,
A main terminal whose land portion and one end are electrically connected by solder joining,
A power semiconductor device configured to include a resin frame frame that covers the periphery of the metal wiring board on which the power semiconductor element is mounted, while being incorporated so that the other end of the main terminal protrudes to the outside. There,
The main terminal is provided with an opening for injecting a solder paste containing a flux at one end thereof to be solder-bonded, and the solder paste is allowed to flow out to a part of the periphery forming the opening. Has a notch,
The notch is provided at a position where the solder paste injected into the opening flows out in a direction deviated from the power semiconductor element and the Ag sinker, and can control the flow of the flux component contained in the solder paste. Power semiconductor device. The main terminal has a tapered shape in which the vertical cross-sectional shape of the opening widens the upper surface side with respect to the lower surface side solder-bonded to the land portion, and the opening expands toward the upper surface. The power semiconductor device described in 1. The power semiconductor device according to claim 1 or 2, wherein the main terminal has a key shape in which the vertical cross-sectional shape of the tip end portion of one end is bent toward the lower surface side to be solder-bonded to the land portion. The power semiconductor device according to any one of claims 1 to 3, further comprising a jig having a mortar shape mounted on the upper surface of the opening and expanding the cross-sectional area of the upper surface of the opening. The power semiconductor device according to claim 4, wherein the jig is integrally molded with the frame.

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