JP2011228604A - Manufacturing method of circuit board and circuit board - Google Patents

Manufacturing method of circuit board and circuit board Download PDF

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Publication number
JP2011228604A
JP2011228604A JP2010099442A JP2010099442A JP2011228604A JP 2011228604 A JP2011228604 A JP 2011228604A JP 2010099442 A JP2010099442 A JP 2010099442A JP 2010099442 A JP2010099442 A JP 2010099442A JP 2011228604 A JP2011228604 A JP 2011228604A
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JP
Japan
Prior art keywords
solder
insulating substrate
circuit
circuit board
semiconductor
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JP2010099442A
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Japanese (ja)
Inventor
Tsugio Masuda
Masami Ogura
Tomoko Yamada
次男 増田
正巳 小倉
友子 山田
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Honda Motor Co Ltd
本田技研工業株式会社
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Priority to JP2010099442A priority Critical patent/JP2011228604A/en
Publication of JP2011228604A publication Critical patent/JP2011228604A/en
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/10Bump connectors; Manufacturing methods related thereto
    • H01L2224/15Structure, shape, material or disposition of the bump connectors after the connecting process
    • H01L2224/16Structure, shape, material or disposition of the bump connectors after the connecting process of an individual bump connector
    • H01L2224/161Disposition
    • H01L2224/16151Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/16221Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/16225Disposition the bump connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321Disposition
    • H01L2224/32151Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32225Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732Location after the connecting process
    • H01L2224/73201Location after the connecting process on the same surface
    • H01L2224/73203Bump and layer connectors
    • H01L2224/73204Bump and layer connectors the bump connector being embedded into the layer connector
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2224/00Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/83Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector
    • H01L2224/831Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector the layer connector being supplied to the parts to be connected in the bonding apparatus
    • H01L2224/83101Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a layer connector the layer connector being supplied to the parts to be connected in the bonding apparatus as prepeg comprising a layer connector, e.g. provided in an insulating plate member
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10Details of semiconductor or other solid state devices to be connected
    • H01L2924/11Device type
    • H01L2924/13Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304Transistor
    • H01L2924/1305Bipolar Junction Transistor [BJT]
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L2924/00Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10Details of semiconductor or other solid state devices to be connected
    • H01L2924/11Device type
    • H01L2924/13Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304Transistor
    • H01L2924/1305Bipolar Junction Transistor [BJT]
    • H01L2924/13055Insulated gate bipolar transistor [IGBT]

Abstract

To provide a circuit board manufacturing method capable of ensuring a certain level of durability reliability and thermal characteristics.
A method of manufacturing a circuit board, comprising: an insulating substrate having a conductive layer; and a circuit element, wherein the conductive layer of the insulating substrate and the circuit element are joined together by solder. A disposing step (step ST1) of disposing a restricting member for restricting a distance between the conductive layer of the insulating substrate and the circuit element on the solder sheet; and the solder on which the insulating substrate and the restricting member are disposed. A lamination step (step ST2) of laminating the sheet and the circuit element in that order, and the laminated insulating substrate, the solder sheet, and the circuit element are heated in a reducing atmosphere to melt the solder sheet. In this way, the circuit board manufacturing method includes a bonding step (step ST3) for bonding the insulating substrate and the circuit element.
[Selection] Figure 5

Description

  The present invention relates to a method for manufacturing a circuit board in which a circuit element and an insulating substrate are bonded using a solder sheet, and a circuit board. Specifically, the present invention relates to a circuit board manufacturing method and a circuit board capable of ensuring a certain level of durability reliability and thermal characteristics.

  Conventionally, solder having good heat conduction and electric conduction and low cost has been used for bonding circuit elements such as power module semiconductor elements to an insulating substrate. In general, the solder often contains an activator having the role of preventing oxidation and improving the bondability. This activator also contributes to the bonding of the circuit element to the insulating substrate. The joining of the circuit element with the solder containing the activator induces a decrease in the adhesion of wire bonding, insufficient resin encapsulation, and the like in a later manufacturing process. For this reason, it is necessary to clean and remove the activator from the solder, but there are many cases in which a residue is generated due to insufficient cleaning management or insufficient cleaning. Therefore, a circuit board manufacturing method using a solder that does not contain an activator and a reducing gas such as hydrogen or formic acid is also provided.

In such a manufacturing method, in order to obtain adhesion at the joint surface between the circuit element and the insulating substrate, a weight load is applied to the circuit element, and the circuit element and the insulating substrate are soldered. Be joined. Hereinafter, such solder bonding is referred to as “solder bonding”.
As a technique applicable to such a manufacturing method, for example, Patent Document 1 discloses a technique in which wire bumps are applied to the back surface of a ceramic circuit board (insulating substrate) and the back surface and the heat sink are joined by solder. . Such a technique is hereinafter referred to as “a technique described in Patent Document 1”. By applying the method described in Patent Document 1, it is possible to suppress the tilt of the ceramic circuit board that occurs during solder bonding.
Further, Patent Document 2 discloses a technique for providing a circuit board provided with outflow suppressing means that improves solder wettability and prevents the solder from flowing out beyond an unexpected region. Such a technique is hereinafter referred to as “a technique described in Patent Document 2”.

JP 2002-158328 A JP 2004-119944 A

  However, although the technique described in Patent Document 1 suppresses the tilt of the ceramic circuit board, the tilt of the circuit element is not taken into consideration. For this reason, if a tilt of the circuit element occurs during solder joining, distortion occurs in the thin part of the solder joint due to the difference in linear expansion coefficient between the circuit element and the solder, and the crack progress of the solder part on the element side is accelerated. There is a risk of deteriorating thermal characteristics (heat dissipation) and lowering durability reliability.

  Moreover, although the technique of the said patent document 2 is not provided with the means to suppress the inclination of a circuit element, although a solder does not flow out exceeding the area | region beyond assumption. Therefore, as in the case of the technique described in Patent Document 1, when the inclination of the circuit element occurs at the time of soldering, the crack progress of the solder portion on the element side is accelerated, which deteriorates the thermal characteristics and the durability reliability. There was a risk of inviting.

  Therefore, there is a recent demand for a circuit board capable of ensuring a certain level of durability reliability and thermal characteristics.

  The present invention has been made in view of such a situation, and is a circuit board manufacturing method and a circuit board in which a circuit element and an insulating substrate are bonded using a solder sheet, and includes durability reliability and thermal characteristics. It is an object of the present invention to provide a circuit board manufacturing method and a circuit board capable of ensuring a certain level or more.

  In the present invention, an insulating substrate (for example, an insulating substrate 2 to be described later) having a conductive layer (for example, a surface side conductive layer 3 and a back surface side conductive layer 4 to be described later) and a circuit element (for example, a semiconductor element 5 to be described later) are provided. And a manufacturing method of a circuit board (for example, a semiconductor substrate 1 described later) in which the conductive layer of the insulating substrate and the circuit element are joined by solder, and a solder sheet (for example, described later) made of the solder A disposing step of disposing a regulating member (for example, a protruding member 8 described later) for controlling a distance (for example, a space d described later) between the conductive layer of the insulating substrate and the circuit element on the solder sheet 7). (E.g., an arrangement process in step ST <b> 1 described later), and a lamination process (e.g., step ST <b> 2 described later) in which the insulating substrate, the solder sheet on which the regulating member is disposed, and the circuit element are stacked in that order. Product of Step) and heating the laminated insulating substrate, the solder sheet, and the circuit element under a reducing atmosphere (for example, a reducing gas 12 described later) to melt the solder sheet, A bonding step of bonding the circuit elements (for example, a bonding step in step ST3 described later).

  According to this invention, by providing the restriction member on the solder sheet, a gap corresponding to the height of the restriction member is formed between the solder sheet and the circuit element. Therefore, a reducing atmosphere is sufficiently supplied to the gap, so that the wettability of the solder on the joint surface can be improved, and the reliability of the joint can be improved. Moreover, it can suppress that a circuit element inclines and is joined with respect to an insulated substrate, and can make thickness of solder uniform. That is, it is possible to suppress the generation and progress of cracks based on the unevenness of the solder thickness, and it is possible to suppress deterioration in heat dissipation (decrease in reliability of thermal characteristics). Therefore, the durability reliability and thermal characteristics of the circuit board can be ensured to a certain level or more.

  In this case, it is preferable that the regulating member (for example, a protruding member 8 described later) is made of a metal material having a higher melting point and lower solder wettability than the solder.

According to the present invention, when the solder sheet is heated at a predetermined temperature higher than the melting point of the solder and lower than the melting point of the regulating member, only the solder sheet is melted, and the regulating member is not melted. It remains in a solid state in the solder. Further, since the regulating member has lower solder wettability than solder, the melted solder easily flows around the regulating member.
Therefore, an interval corresponding to the height of the regulating member is reliably set between the conductive layer of the insulating substrate and the circuit element, and the thickness of the solder can be made uniform.

  In this case, a metal material (for example, an aluminum alloy described later) containing aluminum as a main component can be used for the regulating member (for example, a protruding member 8 described later).

  According to this invention, the manufacturing cost can be reduced by using a versatile metal material for the regulating member.

  In this case, it is preferable that the restriction member (for example, a protruding member 8 described later) is made of a bonding wire.

  According to the present invention, since the regulating member is a bonding wire, a new device for wire bonding is unnecessary, and an existing device can be used. Further, by performing wire bonding, the regulating member can be easily and quickly disposed on the solder sheet. In particular, the regulation member can be automatically supplied to the mass production process by wire bonding to the solder sheet in advance.

  In this case, the solder sheet (for example, a later-described solder sheet 7) is formed in a rectangular shape in a plan view, and the regulation member (for example, a later-described projecting member 8) is formed on two opposite sides (for example, the solder sheet, for example). It is preferable to be disposed along the sides 7c and 7d) described later.

  According to the present invention, in the laminating step, the circuit element can be stably placed on the restriction member of the solder sheet, and the circuit is also provided by the restriction member even when the solder sheet is melted in the joining step. The element can be supported. Thereby, generation | occurrence | production of the inclination of the circuit element with respect to an insulated substrate can be suppressed, and the thickness of solder can be equalize | homogenized. Therefore, it is possible to suppress the occurrence of cracks in the joint portion made of solder, and it is possible to improve the durability reliability of the circuit board.

  In this case, the solder sheet (for example, a solder sheet 7 described later) is preferably made of lead-free solder.

  According to the present invention, a solder joint that does not contain lead can be formed in a circuit board, and an environment-friendly circuit board can be provided.

  A circuit board (for example, a semiconductor substrate 1 described later) of the present invention is an insulating substrate (for example, an insulating substrate 2 described later) having a conductive layer (for example, a front surface side conductive layer 3 and a back surface side conductive layer 4 described later). And a circuit element (for example, a semiconductor element 5 described later), and a joint (for example, a joint 6 described later) for joining the conductive layer of the insulating substrate and the circuit element by solder, The joint is provided with a regulating member (for example, a projection member 8 to be described later) that regulates an interval (for example, a distance d to be described later) between the conductive layer of the insulating substrate and the circuit element. And

  According to this invention, by providing the regulating member, it is possible to suppress the circuit element from being inclined and joined to the insulating substrate, and the thickness of the joint (solder) can be made uniform. Therefore, it is possible to suppress the generation and progress of cracks based on the unevenness of the solder thickness, and it is possible to suppress the deterioration of heat dissipation (reduction in the reliability of the thermal characteristics). Therefore, durability reliability and thermal characteristics can be secured above a certain level.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and circuit board of a circuit board which can ensure durability reliability and thermal characteristics more than fixed can be provided.

It is sectional drawing which shows the semiconductor substrate of embodiment of this invention. It is sectional drawing which decomposes | disassembles and shows the laminated structure of a semiconductor substrate. It is a top view which shows the protrusion member arrange | positioned on the surface of a solder sheet. It is a figure which shows the relationship between the arrangement | positioning position of a protrusion member, and solder distortion. It is a flowchart which shows the manufacturing method of the semiconductor substrate of embodiment of this invention. It is a figure which shows a mode that a reducing gas is supplied between an insulated substrate and a semiconductor element in the joining process in the manufacturing method of FIG.

  Hereinafter, a semiconductor substrate according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a semiconductor substrate according to an embodiment of the present invention, and shows a completed semiconductor substrate. FIG. 2 is an exploded cross-sectional view showing the laminated structure of the semiconductor substrate, and shows the semiconductor substrate before completion. FIG. 3 is a plan view showing a protruding member disposed on the surface of the solder sheet. FIG. 4 is a diagram illustrating the relationship between the position where the protruding member is disposed and the solder strain.

As a circuit board of this embodiment, a semiconductor substrate 1 used for a power module (semiconductor device) of a power supply device (for example, a power supply device for driving a motor) in an automobile or the like will be described as an example.
The semiconductor substrate 1 is formed by joining an insulating substrate 2 having a front-side conductive layer 3 and a back-side conductive layer 4 as conductive layers, a semiconductor element 5 as a circuit element, and the insulating substrate 2 and the semiconductor element 5 with solder. And a protruding member 8 as a restricting member provided at the joint 6.

The insulating substrate 2 is a substrate having electrical insulation, and is made of, for example, ceramics. For example, the insulating substrate 2 is formed in a rectangular shape in plan view.
The surface side conductive layer 3 is provided on the surface 2 a of the insulating substrate 2. Here, the surface 2 a of the insulating substrate 2 is an outer surface of the insulating substrate 2 and is a surface facing the semiconductor element 5. 1 and 2 correspond to the upper surface of the insulating substrate 2. The surface side conductive layer 3 is configured as a conductive pattern (metal circuit layer) such as copper or aluminum.

  The back surface side conductive layer 4 is provided on the back surface 2 b of the insulating substrate 2. Here, the back surface 2b of the insulating substrate 2 is an outer surface of the insulating substrate 2 and is a surface opposite to the front surface 2a. 1 and 2 correspond to the lower surface of the insulating substrate 2. The back side conductive layer 4 is also configured as a conductive pattern such as copper or aluminum.

  The semiconductor element 5 includes, for example, an element group constituting an inverter circuit, specifically, an IGBT (Insulated Gate Bipolar Transistor) that is a switching element, and an FWD (Free Wheeling Diode): a commutation diode. ).

  Although the semiconductor element 5 may be physically separated for each element, in the present embodiment, for convenience of explanation, the semiconductor element 5 is formed in a rectangular shape in plan view. The back surface 5a of the semiconductor element 5 has a predetermined conductive pattern (not shown) that can be bonded to the front surface side conductive layer 3 of the insulating substrate 2 by solder. Here, the back surface 5 a of the semiconductor element 5 refers to the outer surface of the semiconductor element 5 and the surface facing the insulating substrate 2. 1 and 2, the back surface 5 a of the semiconductor element 5 corresponds to the lower surface of the semiconductor element 5. The surface (upper surface) of the semiconductor element 5 is denoted by reference numeral 5b.

As shown in FIG. 1, the joint portion 6 is a portion where the surface-side conductive layer 3 of the insulating substrate 2 and the back surface 5 a of the semiconductor element 5 are joined by solder.
Two protruding members 8 are provided in the joint portion 6. The protruding member 8 will be described later.

Here, with reference to FIG.2 and FIG.3, the outline of the manufacturing method of the junction part 6 is demonstrated.
In the joining process described later (see step ST3 in FIG. 5), the joining portion 6 is formed by solidifying after the solder sheet 7 is melted, as shown in FIG.
As shown in FIG.2 and FIG.3, the solder sheet 7 is the solder comprised in the sheet form. The solder sheet 7 is made of, for example, lead-free solder that does not contain lead. As shown in FIG. 3, the solder sheet 7 is formed in a rectangular shape in plan view, and has almost the same size (area) as the semiconductor element 5 in plan view.

  As shown in FIGS. 2 and 3, two protruding members 8 are disposed on the surface 7 a of the solder sheet 7. Here, the surface 7 a of the solder sheet 7 refers to the outer surface of the solder sheet 7 and the surface facing the semiconductor element 5. In FIG. 2, the surface 7 a of the solder sheet 7 corresponds to the upper surface of the solder sheet 7. Reference numeral 7 b is attached to the back surface (lower surface) of the solder sheet 7.

  When the solder sheet 7 is melted in a joining step (see step ST3 in FIG. 4) described later, the protruding member 8 has an interval d (see FIG. 4) between the front surface side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5. 1) is disposed in the joint portion 6 so as to regulate. This distance d, that is, the height of the protruding member 8 is defined as a minimum dimension that can ensure the reliability of solder joints, and at the same time, is defined as a dimension that can ensure heat dissipation from the semiconductor element 5 to the insulating substrate 2. . For example, the protruding member 8 has a substantially circular cross-sectional shape. The height (diameter) of the two protruding members 8 is substantially the same.

  As shown in FIGS. 2 and 3, the two protruding members 8 are disposed substantially in parallel along two opposing sides (two sides) 7 c and 7 d of the rectangular solder sheet 7. That is, the two protruding members 8 are respectively arranged corresponding to both end portions on the back surface 5 a of the semiconductor element 5.

  Specifically, the protruding member 8 is preferably disposed in the solder sheet 7 at a position that is at least 1.5 mm or more inward from the side 7c or the side 7d. The reason for this is that, as shown in FIG. 4, the protruding member 8 is disposed at an inner position of at least 1.5 mm or more from the side 7c or the side 7d (corresponding to a position of 0 mm on the horizontal axis in FIG. 4). This is because solder distortion is less likely to occur in the joint 6 and the occurrence of cracks due to this distortion can be suppressed. Here, when the numerical value of the solder strain shown on the vertical axis in FIG. 4 is larger than 1, solder strain is generated in a predetermined direction, and when the numerical value is 1, no solder strain is generated. Means.

  The protruding member 8 is made of, for example, a metal material whose main component is aluminum. Here, the metal material mainly composed of aluminum refers to a metal material having a large aluminum component ratio (content), that is, an aluminum alloy. Hereinafter, such an aluminum alloy is simply referred to as aluminum. Aluminum is a metal material having a higher melting point and lower solder wettability (the degree to which the melted solder spreads wet) than the solder that is the material of the solder sheet 7.

  Specifically, the protruding member 8 is made of an aluminum bonding wire. This aluminum bonding wire is generally used for electrically bonding (wire bonding) a surface side electrode (not shown) of the semiconductor element 5 and an external terminal provided on a resin case (not shown). It is a wire used as wiring. That is, in the present embodiment, a bonding wire for wiring is used as the protruding member 8.

  In addition, in order to improve the heat dissipation from the semiconductor element 5, a metal heat sink (not shown) is fixed to the back surface side conductive layer 4 of the insulating substrate 2 using solder or the like. This heat sink is thicker than the insulating substrate 2 and is made of copper, aluminum, or the like.

Next, a method for manufacturing the semiconductor substrate 1 will be described with reference to FIGS. FIG. 5 is a flowchart showing a method for manufacturing the semiconductor substrate 1 according to the embodiment of the present invention. FIG. 6 is a diagram illustrating a state in which a reducing gas is supplied between the insulating substrate and the semiconductor element in the bonding step in the manufacturing method of FIG.
Hereinafter, for convenience of explanation, it is assumed that an operation subject for manufacturing the semiconductor substrate 1 is an apparatus (including a robot) (not shown). However, an operating entity other than the apparatus, for example, a natural person such as an operator, may execute at least a part of the following steps.

  As shown in FIG. 5, in step ST <b> 1, the apparatus performs an operation of an arrangement process. This arrangement | positioning process is a process in which the apparatus arrange | positions the protrusion member 8 in the predetermined location of the solder sheet 7 (refer FIG.2 and FIG.3). For example, the apparatus disposes the protruding member 8 on the solder sheet 7 by wire bonding an aluminum bonding wire to be the protruding member 8. As a result, as shown in FIG. 6, the surface 7 a of the solder sheet 7 corresponds to the height (interval d) of the protruding member 8 in the portion where the protruding member 8 is disposed and the portion where the protruding member 8 is not disposed. Height difference is possible.

Next, in step ST2, the apparatus performs an operation of a stacking process. As shown in FIG. 6, this stacking process is a process in which the apparatus stacks the insulating substrate 2, the solder sheet 7 provided with the protruding members 8, and the semiconductor element 5 in the order in the upward direction in the figure. is there. At this time, the apparatus places a predetermined weight 10 on the surface 5 b (upper surface) of the semiconductor element 5 in order to obtain adhesion between the stacked members.
Since the protruding member 8 is disposed on the front surface 7 a of the solder sheet 7, a gap d is formed between the front surface 7 a of the solder sheet 7 and the back surface 5 a of the semiconductor element 5.

  Next, in step ST3, the apparatus performs an operation of a bonding process. As shown in FIG. 6, in this joining process, the apparatus puts the insulating substrate 2, the solder sheet 7, the semiconductor element 5 and the weight 10 laminated in step ST2 into a reflow furnace (not shown), and a reducing gas. In this process, the insulating substrate 2 and the semiconductor element 5 are soldered together by melting the solder sheet 7 by heating at a predetermined temperature while supplying 12.

  As the reducing gas 12, for example, hydrogen gas is used. According to the reduction reaction using hydrogen gas, pollutants are not generated and only water (water vapor) is generated, which is preferable for the environment.

  By disposing the protruding member 8 on the surface 7 a of the solder sheet 7, the gap d is formed between the surface 7 a of the solder sheet 7 and the back surface 5 a of the semiconductor element 5. Therefore, the flow path of hydrogen gas can be secured by this gap, and hydrogen gas can be sufficiently supplied to this gap.

  When hydrogen gas is supplied to the gap, the oxide contained in the molten solder is removed by the reducing action of the hydrogen gas, and is formed on the surface side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5. The oxidized film and the like that have been removed are also removed. Therefore, the wettability of the solder is improved and the reliability of the solder joint is improved.

  The predetermined temperature at the time of heating is a temperature at which the solder sheet 7 melts but the protruding member 8 does not melt. By heating at this temperature, only the solder sheet 7 is melted. Then, due to the action of the weight 10, the semiconductor element 5 and the protruding member 8 sink toward the surface-side conductive layer 3 side of the insulating substrate 2, and the protruding member 8 contacts the surface-side conductive layer 3. Thereafter, the melted solder is cooled and solidified. That is, the front surface side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5 are bonded to each other by solder, thereby forming the bonding portion 6 (see FIG. 1). In addition, since the protruding member 8 is disposed in the bonding portion 6, the thickness of the bonding portion 6 does not partially become lower than the height of the protruding member 8.

As described above, in the method for manufacturing the semiconductor substrate 1 according to the present embodiment, the distance d between the surface-side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5 is regulated on the solder sheet 7 made of solder. A disposing step (step ST1) for disposing the protruding member 8, and a laminating step (step ST2) for laminating the insulating substrate 2, the solder sheet 7 on which the protruding member 8 is disposed, and the semiconductor element 5 in that order. A bonding step (step for bonding the insulating substrate 2 and the semiconductor element 5 by heating the laminated insulating substrate 2, the solder sheet 7 and the semiconductor element 5 under the reducing gas 12 to melt the solder sheet 7. ST3).
Thereby, each effect shown as the following (1) thru / or (6) is produced.

  (1) Since the protruding member 8 is disposed on the solder sheet 7, a gap having a distance d corresponding to the height of the protruding member 8 is provided between the front surface 7 a of the solder sheet 7 and the back surface 5 a of the semiconductor element 5. Is formed. Therefore, the reducing gas 12 is sufficiently supplied to this gap, so that the wettability of the solder on the joint surface can be improved, and the reliability of the solder joint can be improved. Moreover, it can suppress that the semiconductor element 5 inclines with respect to the insulated substrate 2 and is soldered, and can make the thickness of the junction part 6 (solder) uniform. That is, since it can suppress that the junction part 6 becomes thin partially, generation | occurrence | production and progress of the crack based on nonuniformity of solder thickness can be suppressed, and heat dissipation deteriorates (reliability of thermal characteristics). Reduction) can be suppressed. Therefore, the durability reliability and thermal characteristics of the circuit board 1 can be ensured to a certain level or more.

(2) The protruding member 8 is made of an aluminum bonding wire. Aluminum is a versatile metal material, and the production cost can be reduced by using aluminum. Aluminum is a metal material having a higher melting point and lower solder wettability than the solder that is the material of the solder sheet 7. Therefore, by heating the solder sheet 7 at a predetermined temperature, it is possible to melt only the solder sheet 7 and leave the protruding member 8 in a solid state in the melted solder. Further, since the protruding member 8 has lower solder wettability than the solder, the molten solder easily flows around the protruding member 8.
Accordingly, a distance d corresponding to the height (diameter) of the protruding member 8 is reliably set between the front surface side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5, and the bonding portion 6 (solder) is fixed. The thickness can be made uniform.

  (3) Since the protruding member 8 is made of an aluminum bonding wire, a new device for wire bonding is unnecessary, and an existing device can be used. Moreover, the protruding member 8 can be easily and quickly disposed on the solder sheet 7 by wire bonding. In particular, the protruding member 8 can be automatically supplied to the mass production process by wire bonding to the solder sheet 7 in advance.

  (4) Further, the solder sheet 7 is formed in a rectangular shape in plan view, and the protruding member 8 is disposed along two opposing sides 7 c and 7 d in the solder sheet 7. Therefore, the semiconductor element 5 can be stably placed on the two protruding members 8 of the solder sheet 7 during the stacking step, and the protrusion is also generated when the solder sheet 7 is melted during the bonding step. The semiconductor element 5 can be supported by the member 8. Thereby, generation | occurrence | production of the inclination of the semiconductor element 5 with respect to the insulated substrate 2 can be suppressed, and the thickness of solder (joining part 6) can be equalize | homogenized. Therefore, it is possible to suppress the occurrence of cracks in the joint 6 and improve the durability reliability of the semiconductor substrate 1.

  (5) The solder sheet 7 is made of lead-free solder. Therefore, in the semiconductor substrate 1, the junction part 6 which does not contain lead can be comprised, and the environmentally friendly semiconductor substrate 1 can be provided. This lead-free solder is known to be harder than lead-based solder or tin-lead solder. Therefore, when the thickness of the joining portion 6 (solder) of the semiconductor substrate 1 is not formed uniformly, distortion occurs in a portion where the solder thickness is thin due to the difference in linear expansion coefficient between the semiconductor element 5 and the solder, and the crack progresses. There is a risk of getting early. However, in the present embodiment, as described above, since the thickness of the joint portion 6 can be formed uniformly, there is no possibility that the progress of cracks is accelerated, and lead-free solder can be used.

  (6) Moreover, in order to ensure the solder wettability in a joining surface, conventionally, processing a solder material into a columnar shape with a thickness thicker than a sheet | seat was performed. For this reason, the number of molds used has been drastically reduced, and the processing cost has been greatly increased. However, in the present embodiment, for the reasons described above, even if a sheet-like lead-free solder is used, solder wettability can be easily ensured, so that it is not necessary to process the solder material into a cylindrical shape. Therefore, the manufacturing cost can be reduced.

  Further, the semiconductor substrate 1 manufactured by the manufacturing method includes an insulating substrate 2 having a front surface side conductive layer 3 and a back surface side conductive layer 4, a semiconductor element 5, a front surface side conductive layer 3 of the insulating substrate 2, and the semiconductor element 5. A projecting member that regulates the distance d between the surface-side conductive layer 3 of the insulating substrate 2 and the back surface 5a of the semiconductor element 5. 8 is provided.

  Therefore, by providing the protruding member 8, it is possible to suppress the semiconductor element 5 from being tilted and soldered to the insulating substrate 2, and to make the thickness of the joint 6 (solder) uniform. . Therefore, it is possible to suppress the occurrence and development of cracks based on the unevenness of the solder thickness, and to ensure the durability reliability and thermal characteristics of the circuit board 1 to a certain level or more.

As mentioned above, although one Embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above, It can change suitably.
For example, in the above-described embodiment, the protruding member 8 has been described as being disposed along the two opposing sides 7c and 7d of the solder sheet 7, but is not limited thereto. If the flow path of the reducing gas 12 can be secured and the semiconductor element 5 can be stably placed, one or three or more projecting members 8 may be disposed, The arrangement position is also arbitrary.

  Moreover, in the said embodiment, although the semiconductor element 5 used for a power module was demonstrated as an example as a circuit element, it is not restrict | limited to this. For example, the circuit element may be other electrical components instead of the semiconductor element.

  Moreover, in the said embodiment, although the solder sheet 7 demonstrated as what consists of lead-free solder which does not contain lead, it is not restrict | limited to this. For example, the solder sheet 7 may be made of lead solder, tin-lead eutectic solder, or the like. In addition to the solder used for joining the semiconductor element 5, the solder is joined to a heat sink made of metal such as aluminum or copper and subjected to a surface treatment such as nickel plating. It can also be used.

  Moreover, in the said embodiment, although demonstrated as what uses hydrogen as the reducing gas 12 in a joining process, it is not restrict | limited to this. For example, formic acid may be used as the reducing gas 12.

  In the above-described embodiment, the semiconductor substrate 1 used in the power module of the power supply device in an automobile or the like has been described as an example. However, the present invention is not limited to this. For example, any circuit board may be used as long as it is a solder-bonded circuit board, and electrical parts other than the circuit board may be used.

1 Semiconductor substrate (circuit board)
2 Insulating substrate 3 Surface side conductive layer (conductive layer)
4 Back side conductive layer (conductive layer)
5 Semiconductor elements (circuit elements)
6 Joint 7 Solder sheet 7c, 7d Side 8 Projection member (regulation member)
12 Reducing gas (reducing atmosphere)
d interval

Claims (7)

  1. A method of manufacturing a circuit board comprising an insulating substrate having a conductive layer and a circuit element, wherein the conductive layer of the insulating substrate and the circuit element are joined by solder,
    A disposing step of disposing a restricting member for restricting a distance between the conductive layer of the insulating substrate and the circuit element on the solder sheet composed of the solder;
    A laminating step of laminating the insulating substrate, the solder sheet on which the regulating member is disposed, and the circuit element;
    Bonding the insulating substrate and the circuit element by heating the laminated insulating substrate, the solder sheet and the circuit element in a reducing atmosphere to melt the solder sheet;
    A method of manufacturing a circuit board including:
  2.   The method of manufacturing a circuit board according to claim 1, wherein the regulating member is made of a metal material having a higher melting point and lower solder wettability than the solder.
  3.   The circuit board manufacturing method according to claim 2, wherein the regulating member is made of a metal material mainly composed of aluminum.
  4.   The circuit board manufacturing method according to claim 3, wherein the regulating member is made of a bonding wire.
  5. The solder sheet is formed in a rectangular shape in plan view,
    The circuit board manufacturing method according to claim 1, wherein the regulating member is disposed along two opposing sides of the solder sheet.
  6.   The circuit board manufacturing method according to claim 1, wherein the solder sheet is made of lead-free solder.
  7. An insulating substrate having a conductive layer;
    Circuit elements;
    A joint that joins the conductive layer of the insulating substrate and the circuit element with solder;
    With
    A circuit board provided with a restricting member for restricting a distance between the conductive layer of the insulating substrate and the circuit element at the joint.
JP2010099442A 2010-04-23 2010-04-23 Manufacturing method of circuit board and circuit board Pending JP2011228604A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016219565A1 (en) * 2016-10-07 2018-04-12 Continental Automotive Gmbh Power electronics circuit

Citations (6)

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Publication number Priority date Publication date Assignee Title
JPH03218030A (en) * 1990-01-23 1991-09-25 Hitachi Ltd Semiconductor integrated circuit device and preform bonding material used in the same
JPH05343446A (en) * 1992-06-11 1993-12-24 Toshiba Corp Manufacture of semiconductor device
JPH11186331A (en) * 1997-12-19 1999-07-09 Mitsubishi Electric Corp Semiconductor device and its manufacture
JP2001168252A (en) * 1999-12-07 2001-06-22 Shibafu Engineering Kk Semiconductor device and manufacturing method thereof
JP2003260586A (en) * 2002-03-08 2003-09-16 富士電機株式会社 Reduction-type solder joining apparatus
JP2008227189A (en) * 2007-03-13 2008-09-25 Toyota Motor Corp Solder joining method and apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03218030A (en) * 1990-01-23 1991-09-25 Hitachi Ltd Semiconductor integrated circuit device and preform bonding material used in the same
JPH05343446A (en) * 1992-06-11 1993-12-24 Toshiba Corp Manufacture of semiconductor device
JPH11186331A (en) * 1997-12-19 1999-07-09 Mitsubishi Electric Corp Semiconductor device and its manufacture
JP2001168252A (en) * 1999-12-07 2001-06-22 Shibafu Engineering Kk Semiconductor device and manufacturing method thereof
JP2003260586A (en) * 2002-03-08 2003-09-16 富士電機株式会社 Reduction-type solder joining apparatus
JP2008227189A (en) * 2007-03-13 2008-09-25 Toyota Motor Corp Solder joining method and apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102016219565A1 (en) * 2016-10-07 2018-04-12 Continental Automotive Gmbh Power electronics circuit

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