JP6279860B2 - Semiconductor device - Google Patents

Description

  The present invention relates to a semiconductor device.

  The power semiconductor device is a semiconductor device used for controlling and rectifying relatively large power in, for example, a railway vehicle, a vehicle such as a hybrid car or an electric vehicle, a home appliance, or an industrial device. Since this power semiconductor device is used in a high temperature region, the bonding between the metal terminal and the semiconductor pattern is switched from the conventional solder bonding to the ultrasonic bonding.

  In general, the metal terminal has an L-shape, and is bonded to the metal pattern by ultrasonic bonding as follows. First, the flat tip is brought into contact with the metal pattern on the insulating substrate. A semiconductor chip or the like is mounted on the insulating substrate. Next, the metal terminal is pressed using the tool of the ultrasonic generator, ultrasonic vibration is applied to the tool, and the metal terminal and the tool are operated integrally. In this way, friction is generated between the metal terminal and the metal pattern on the insulating substrate, thereby joining the metal terminal and the metal pattern (for example, see Patent Document 1).

JP 2006-278913 A

  In the conventional semiconductor device, it is difficult to stably bond the metal terminal and the metal pattern on the insulating substrate, and there is a problem in the reliability of the device. Accordingly, an object of the present invention is to provide a semiconductor device capable of stably joining a metal terminal to a metal pattern on a substrate.

A semiconductor device according to a first aspect of the present invention includes a substrate including a metal pattern and a metal terminal connected to the metal pattern. The metal terminal extends along the surface of the metal pattern, and is connected to the metal pattern, a support portion extending in a direction different from the direction in which the joint portion extends, and the joint portion And a first bent portion extending linearly in a direction different from each of a direction in which the joint portion extends and a direction in which the support portion extends. Only the joint portion is brought into contact with the metal pattern, and the first bent portion and the support portion are configured to be separated from the metal pattern. The metal terminal is connected to the metal pattern by ultrasonic bonding, and the width of the bonding portion is the same as the width of the ultrasonic tool used for ultrasonic bonding.

A semiconductor device according to a second aspect of the present invention includes a substrate including a metal pattern and a metal terminal connected to the metal pattern. The metal terminal extends along the surface of the metal pattern, and is connected to the metal pattern, a support portion extending in a direction different from the direction in which the joint portion extends, and the joint portion And a bent portion having a radius of curvature equal to or greater than the thickness of the metal terminal. Only the joint portion is brought into contact with the metal pattern, and the bent portion and the support portion are configured to be separated from the metal pattern. The metal terminal is connected to the metal pattern by ultrasonic bonding, and the width of the bonding portion is the same as the width of the ultrasonic tool used for ultrasonic bonding.

A semiconductor device according to a third aspect of the present invention includes a substrate including a metal pattern and a metal terminal connected to the metal pattern. The metal terminal extends along the surface of the metal pattern, and has a joint having a convex portion connected to the metal pattern on the surface facing the metal pattern, and is connected to the joint. And a support portion extending in a direction different from the extending direction. Only a convex part is made to contact a metal pattern, and it comprises so that a support part may leave | separate from a metal pattern. The metal terminal is connected to the metal pattern by ultrasonic bonding, and the width of the bonding portion is the same as the width of the ultrasonic tool used for ultrasonic bonding.

  According to the semiconductor device according to the present invention, it is possible to provide a semiconductor device capable of stably bonding a metal terminal to a metal pattern of a substrate.

It is a schematic sectional drawing which shows the structure of the semiconductor device which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the semiconductor device which concerns on the modification of Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the semiconductor device which concerns on Embodiment 2 of this invention. It is the schematic which expands and shows the structure of the semiconductor device which concerns on Embodiment 2 of this invention. It is a schematic sectional drawing which shows the structure of the semiconductor device which concerns on Embodiment 3 of this invention. It is a schematic sectional drawing which shows the structure of the semiconductor device of a comparative example. It is a schematic sectional drawing which shows the structure of the semiconductor device of a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
First, Embodiment 1 which is the first embodiment of the present invention will be described. First, the structure of the semiconductor device according to this embodiment will be described. Referring to FIG. 1, semiconductor device 1 according to the present embodiment is a power semiconductor device, and includes substrate 10 including base plate 11, solder layer 12, ceramic plate 13 and metal pattern 14, and metal pattern 14. It mainly includes a metal terminal 15 to be connected.

  The ceramic plate 13 is fixed to the base plate 11 via the solder layer 12. The metal pattern 14 is formed on one surface (surface opposite to the solder layer 12 side) of the ceramic plate 13. The metal pattern 14 is made of a metal material such as copper (Cu) or aluminum (Al).

  The metal terminal 15 is connected to a joint portion 15a connected to the metal pattern 14, a terminal bent portion 15b (first bent portion) connected to the joint portion 15a so as to be separated from the metal pattern 14, and a terminal bent portion 15b. And a support portion 15c. The metal terminal 15 is made of a metal material such as copper (Cu), for example.

  The joint portion 15a (metal terminal 15) extends along the surface 14a of the metal pattern 14, and is connected to the metal pattern 14 by ultrasonic joining. More specifically, the bonding portion 15a transmits ultrasonic vibration to the bonding portion 15a by bringing the ultrasonic tool 50 into contact with the surface 15a2, and causes friction between the bonding surface 15a1 and the surface 14a. Thus, the metal pattern 14 is bonded. The width W1 of the joining portion 15a is ± 20% or less (80% or more and 120% or less) of the width W2 of the ultrasonic tool 50 used for the ultrasonic bonding, and is preferably the same size. For example, when the width W2 of the ultrasonic tool 50 is 5 mm, the width W1 of the joint portion 15a is 6 mm or 4 mm.

  The support portion 15c extends in a direction different from the direction in which the joint portion 15a extends. More specifically, the support portion 15 c extends along a direction perpendicular to the direction along the surface 14 a of the metal pattern 14.

  The terminal bent portion 15b extends linearly so as to connect one end of the joint 15a and one end of the support 15c. The terminal bent portion 15b extends linearly in a direction different from the direction in which the joint portion 15a extends and the direction in which the support portion 15c extends. More specifically, the terminal bending part 15b is extended in the direction which cross | intersects the extension direction of the junction part 15a, and the extension direction of the support part 15c.

  As shown in FIG. 1, the metal terminal 15 has a structure in which a joint portion 15a, a terminal bent portion 15b, and a support portion 15c are integrally formed. More specifically, the metal terminal 15 is formed by pressing a single flat metal member (not shown) or the like to provide a plurality of bending points.

  In the metal terminal 15, the bending angle at the bending point is not particularly limited. For example, the angle formed by the extending direction of the joint portion 15a and the extending direction of the terminal bent portion 15b and the angle formed by the extending direction of the terminal bent portion 15b and the extending direction of the support portion 15c are 0 °. And less than 90 °, and the sum of the angles is 90 °. As a result, as shown in FIG. 1, the joint 15a extends along the surface 14a of the metal pattern 14, and the support 15c extends along a direction perpendicular to the surface 14a.

  Next, a method for manufacturing a semiconductor device according to the present embodiment will be described. In this method of manufacturing a semiconductor device, first, a step of preparing a substrate and a metal terminal is performed. In this step, a substrate 10 including a base plate 11, a solder layer 12, a ceramic plate 13, and a metal pattern 14 is prepared with reference to FIG. A metal terminal 15 made of a material such as copper is also prepared separately.

  Next, a step of ultrasonic bonding is performed. In this step, referring to FIG. 1, first, the metal terminal 15 is arranged on the substrate 10 so that the joint portion 15 a contacts the metal pattern 14. Next, the ultrasonic tool 50 is brought into contact with the metal terminal 15 from the surface 15a2 side, and ultrasonic vibration is transmitted to the joint portion 15a. As a result, friction is generated between the metal terminal 15 (joining portion 15 a) and the metal pattern 14, and the metal terminal 15 is joined to the metal pattern 14. The semiconductor device 1 is manufactured as described above.

  Next, functions and effects of the semiconductor device according to the present embodiment will be described with reference to a semiconductor device of a comparative example. 6 and 7, a semiconductor device 100 of a comparative example includes a base plate 110, a solder layer 120, a ceramic plate 130, a substrate including a metal pattern 140, and a metal terminal 150 connected to the metal pattern 140. And a case 200 are mainly provided. As shown in FIG. 7, the metal terminal 150 is branched into a plurality of pieces, and each metal terminal 150 has an L-shape including a joint 150a and a support 150c (see FIG. 6). The number of branches of the metal terminal 150 differs depending on the product, for example, 2 to 10 (three in FIG. 7).

  In the semiconductor device 100, the ultrasonic tool 500 is used to press the joint 150 a of the metal terminal 150 to apply ultrasonic vibration and a load to the joint 150 a, thereby generating friction between the metal terminal 150 and the metal pattern 140. These are joined together. In this case, as shown in FIG. 6, the width of the joint 150 a is larger than the width of the ultrasonic tool 500. That is, the bonding part 150 a includes a bonding region 151 a bonded to the metal pattern 140 and a non-bonding region 152 a that is not bonded, and both the bonding region 151 a and the non-bonding region 152 a are in contact with the metal pattern 140. doing. When the metal terminal 150 is pressed by the ultrasonic tool 500 in this state, not only the bonding region 151 a but also the non-bonding region 152 a may be bonded to the metal pattern 140. In this case, the bonding load applied by the ultrasonic tool 500 is dispersed, and unnecessary frictional resistance or the like is generated to cause variation in bonding strength. As a result, the reliability of bonding of the metal terminal 150 to the metal pattern 140 is lowered. There are concerns.

  More specifically, even when the bonding portion 150a has a flat surface, depending on the processing conditions of ultrasonic bonding, only the end portion may be bonded and the central portion may not be bonded. For example, when the metal terminal 150 is made of copper, the thickness is 1.5 mm, the width is 5 mm, the length is 7 mm, and ultrasonic bonding is performed under the conditions of a frequency of 20 kHz, an amplitude of 25 μm, and a load of 1000 N, only the end of the terminal is In some cases, the central part is not joined. On the other hand, when the load is reduced from 1000 N to 500 N and the amplitude is reduced from 25 μm to 20 μm, the central portion of the terminal can be joined. Thus, in the semiconductor device 100 of the comparative example, it is difficult to ensure stable bonding between the metal terminal 150 and the metal pattern 140 unless the ultrasonic bonding conditions such as load and amplitude are set in detail.

  On the other hand, in the semiconductor device 1 according to the present embodiment, the metal terminal 15 further includes a terminal bent portion 15b in addition to the joint portion 15a and the support portion 15c. Thereby, only the part (joining part 15a) joined to the metal pattern 14 in the metal terminal 15 is made to contact with the said metal pattern 14, and other parts (terminal bending part 15b and support part 15c) are separated from the metal pattern 14. It becomes easy to constitute. As a result, a load is uniformly applied to the entire bonding surface by the ultrasonic tool 50 during ultrasonic bonding, and a stable bonding between the metal terminal 15 and the metal pattern 14 can be obtained. Furthermore, by providing a plurality of bending points on the metal terminal 15, it is possible to further alleviate distortion at the joint between the metal terminal 15 and the metal pattern 14 due to expansion and contraction due to heat when the semiconductor device is used. As described above, in the semiconductor device 1 according to the present embodiment, stable bonding between the metal terminal 15 and the metal pattern 14 is achieved, and the reliability is further improved.

(Modification)
Next, a modification of the present embodiment will be described. The semiconductor device according to the present modification basically has the same configuration as that of the semiconductor device 1 according to the present embodiment and has the same effects. However, the semiconductor device according to the present modification is different from the semiconductor device 1 according to the present embodiment in the structure of the metal terminal.

  Referring to FIG. 2, the semiconductor device 2 according to the present modification includes a base plate 21, a solder layer 22, a ceramic plate 23, and a metal pattern 24 as well as the semiconductor device 1, and metal terminals 25. Mainly prepared. The metal terminal 25 further includes a distal end side terminal bent portion 25d (second bent portion) in addition to the joint portion 25a, the terminal bent portion 25b (first bent portion), and the support portion 25c.

  The distal end side terminal bent portion 25d is connected to the joint portion 25a on the side opposite to the terminal bent portion 25b. The distal-end-side terminal bent portion 25b extends in a direction different from the direction in which the joint portion 25a extends (the direction along the surface 24a of the metal pattern 24). With the above configuration, as in the case of the semiconductor device 1, the metal terminal 25 and the metal pattern 24 can be stably joined, and the degree of freedom in designing the metal terminal 15 can be further improved.

(Embodiment 2)
Next, a second embodiment which is a second embodiment of the present invention will be described. The semiconductor device according to the second embodiment basically has the same configuration as that of the semiconductor device 1 according to the first embodiment and has the same effects. However, the semiconductor device according to the second embodiment is different from the semiconductor device 1 according to the first embodiment in the structure of the metal terminal.

  With reference to FIG. 3, the semiconductor device 3 according to the present embodiment, like the semiconductor device 1, includes a base plate 31, a solder layer 32, a ceramic plate 33 and a metal pattern 34, and the metal pattern 34. And a metal terminal 35 connected to the main body. In addition to the joint portion 35a and the support portion 35c, the metal terminal 35 further includes a bent portion 35b that bends so as to connect the joint portion 35a and the support portion 35c.

  The joining portion 35a extends along the surface 34a of the metal pattern 34 and is connected to the metal pattern 34 by ultrasonic joining. The width W1 of the bonding portion 35a is a size of ± 20% or less (80% or more and 120% or less) of the width W2 of the ultrasonic tool 50 used for the ultrasonic bonding. The support part 35c extends along a direction (a direction perpendicular to the surface 34a of the metal pattern 34) different from the direction in which the joint part 34 extends.

  With reference to FIG. 4, the curvature radius of the bent portion 35 b is larger than the thickness of the metal terminal 35. More specifically, the curvature radius R (the radius of the curvature circle C) of the curve 35b1 included in the bent portion 35b is greater than or equal to the thickness T1 of the metal terminal 35. For example, when the thickness T1 of the metal terminal 35 is 1.5 mm, the curvature radius R is 1.5 mm or more.

  With the above configuration, in the semiconductor device 3 according to the present embodiment, only the portion (joint portion 35a) to be joined to the metal pattern 34 is provided even when the metal terminal 35 is small in size and it is difficult to provide a plurality of bending points. Can be easily configured so as to be in contact with the metal pattern 34 and other portions away from the metal pattern 34. As a result, a stable bonding between the metal terminal 35 and the metal pattern 34 can be obtained as in the semiconductor device 1.

(Embodiment 3)
Next, Embodiment 3 which is the third embodiment of the present invention will be described. The semiconductor device according to the third embodiment basically has the same configuration as that of the semiconductor device 1 according to the first embodiment and has the same effects. However, the semiconductor device according to the third embodiment is different from the semiconductor device 1 according to the first embodiment in the structure of the metal terminal.

  Referring to FIG. 5, the semiconductor device 4 according to the present embodiment, like the semiconductor device 1, includes a base plate 41, a solder layer 42, a ceramic plate 43, and a metal pattern 44, and the metal pattern 44. And a metal terminal 45 connected to the main body. The metal terminal 45 includes a joint portion 45a and a support portion 45c. The metal pattern 44 and the metal terminal 45 are made of a metal material such as copper (Cu), for example.

  The joint portion 45a extends along the surface 44a of the metal pattern 44 and is connected to the metal pattern 44 by ultrasonic joining. More specifically, the joint portion 45 a has a convex portion 45 d on the surface facing the metal pattern 44, and is connected to the metal pattern 44 at the convex portion 45 d. The width W3 of the convex portion 45d is ± 20% or less (80% or more and 120% or less) of the width W2 of the ultrasonic tool 50 used for the ultrasonic bonding, and is preferably the same size. For example, when the width W2 of the ultrasonic tool 50 is 5 mm, the width W3 of the convex portion 45d is 4 to 6 mm.

  Further, when the metal terminal 45 and the metal pattern 44 are made of copper, the width of the joint portion 45a is 5 mm, and the thickness of the metal terminal 45 is 1.5 mm, the metal terminal 45 and the metal pattern 44 are joined by ultrasonic joining. The amount of deformation due to surface scraping and compression is about 10 to 100 μm. For this reason, the step H of the convex portion 45d is appropriately set according to the conditions of ultrasonic bonding, but is at least 10 μm or more.

  The support part 45c is connected to one end of the joint part 45a. The support portion 45c extends along a direction (a direction perpendicular to the surface 44a) different from a direction (a direction along the surface 44a of the metal pattern 44) in which the joint portion 45a extends.

  With the above configuration, in the semiconductor device 4 according to the present embodiment, it is possible to avoid contact with the metal pattern 44 on either the tip side or the base side (side connected to the support portion 45c) of the joint portion 45a. it can. Thereby, only the part (convex part 45d) joined to the metal pattern 44 can be made to contact the metal pattern 44, and another part can be easily separated from the metal pattern 44. As a result, it is possible to obtain a stable joint between the metal terminal 45 and the metal pattern 44 as in the semiconductor device 1.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The semiconductor device of the present invention can be particularly advantageously applied to a semiconductor device in which a metal terminal is required to be stably bonded to a metal pattern of a substrate.

  1, 2, 3, 4 Semiconductor device 10, 20, 30, 40 Substrate, 11, 21, 31, 41 Base plate, 12, 22, 32, 42 Solder layer, 13, 23, 33, 43 Ceramic plate, 14 , 24, 34, 44 Metal pattern, 14a, 15a2, 24a, 34a, 44a Surface, 15, 25, 35, 45 Metal terminal, 15a, 25a, 35a, 45a Joint part, 15a1 Joint surface, 15b, 25b Terminal bending part , 25d distal end side terminal bent portion, 15c, 25c, 35c, 45c support portion, 35b bent portion, 35b1 curve, 45d convex portion, 50 ultrasonic tool.

Claims (4)

A substrate including a metal pattern;
A metal terminal connected to the metal pattern,
The metal terminal is
A joint extending along the surface of the metal pattern and connected to the metal pattern;
A support portion extending in a direction different from a direction in which the joint portion extends;
Connecting the joint and the support, and includes a first bent portion extending linearly in a direction different from each of a direction in which the joint extends and a direction in which the support extends.
Only the joint portion is brought into contact with the metal pattern, and the first bent portion and the support portion are configured to be separated from the metal pattern ,
The metal terminal is connected to the metal pattern by ultrasonic bonding,
The width | variety of the said junction part is a semiconductor device which is the same magnitude | size as the width | variety of the ultrasonic tool used for the said ultrasonic bonding .   The metal terminal further includes a second bent portion that is connected to the joint portion on a side opposite to the first bent portion side and extends in a direction different from a direction in which the joint portion extends. The semiconductor device described. A substrate including a metal pattern;
A metal terminal connected to the metal pattern,
The metal terminal is
A joint extending along the surface of the metal pattern and connected to the metal pattern;
A support portion extending in a direction different from a direction in which the joint portion extends;
Bending to connect the joint and the support, and a bent portion having a radius of curvature equal to or greater than the thickness of the metal terminal,
Only the joint portion is brought into contact with the metal pattern, and the bent portion and the support portion are configured to be separated from the metal pattern ,
The metal terminal is connected to the metal pattern by ultrasonic bonding,
The width | variety of the said junction part is a semiconductor device which is the same magnitude | size as the width | variety of the ultrasonic tool used for the said ultrasonic bonding . A substrate including a metal pattern;
A metal terminal connected to the metal pattern,
The metal terminal is
A joint that extends along the surface of the metal pattern and has a convex portion connected to the metal pattern on the surface facing the metal pattern;
A support portion connected to the joint portion and extending in a direction different from a direction in which the joint portion extends;
Only the convex part is brought into contact with the metal pattern, and the support part is configured to be separated from the metal pattern,
The metal terminal is connected to the metal pattern by ultrasonic bonding,
The width | variety of the said junction part is a semiconductor device which is the same magnitude | size as the width | variety of the ultrasonic tool used for the said ultrasonic bonding .

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