JPH077152U - Semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the environmental resistance of semiconductor devices. [Structure] A structure is provided in which a header portion (3a) of a lead (3) is fixed to one main surface of a diode chip (1), and a metal laminate is fixed to the other main surface of the diode chip (1). The metal laminate is composed of a main metal layer (8) (11) made of a metal having a smaller linear expansion coefficient than copper, and a main metal layer (8) (1).
1) The first copper layer (7) (10) fixed between one main surface of the diode chip (1) and the other main surface of the diode chip (1) and the other main surface of the main metal layer (8). Affixed second copper layer (9) (1
2) and are provided. Since the main metal layer (8) of the metal laminate has a small linear expansion coefficient, the thermal stress of the diode chip (1) caused by the difference in linear expansion coefficient between the bowl-shaped electrode (2) and the diode chip (1) is alleviated. It is possible to prevent the diode chip (1) from being damaged. Further, since the thickness of the solder (6) interposed between the header portion (3a) and the diode chip (1) is ⅔ or more of the thickness of the diode chip (1), the difference in linear expansion coefficient between them. The thermal stress caused by is also relaxed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a semiconductor device, and particularly to a semiconductor device having high environmental resistance.

[0002]

[Prior art]

 As shown in FIG. 4, the diode chip (1) is fixed between the bowl-shaped electrode (2) also serving as a plate-shaped copper heat sink and the header part (3a) of the lead (3), and the diode chip (1) is fixed. An output rectifier diode for an automobile alternator in which the inside of the lead (3) and the lead (3) are sealed by a protective resin (4) filled in a bowl-shaped electrode (2) which also serves as a heat sink is known. The diode chip (1) and the heat sink (2) are fixed by solder (5), and the diode chip (1) and the header (3a) of the lead (3) are fixed by solder (6). To be done.

[0003]

[Problems to be solved by the device]

 By the way, it was confirmed that the electrical characteristics of the diode chip (1) deteriorated when the diode of Fig. 4 was used in a severe environment in which heat cycles were repeated many times. This is due to the large linear expansion coefficient of the diode chip (1) and the bowl-shaped electrode (2) and the lead (3) when the heat cycle is repeatedly applied to the diode. This is considered to be due to the application of dynamic stress.

Therefore, an object of the present invention is to provide a semiconductor device in which electrical characteristics are not deteriorated for a long period of time even in a severe environment in which thermal shock is repeatedly applied many times.

[0005]

[Means for Solving the Problems]

 A semiconductor device according to the present invention includes a semiconductor chip, a lead having a header portion fixed to one main surface of the semiconductor chip by a solder, a bowl-shaped electrode fixed to the other main surface of the semiconductor chip, and a bowl. A protective resin filled in the shaped electrode and sealing the inside of the semiconductor chip and the lead. The bowl-shaped electrode is composed of a metal laminate. The metal laminate is a first metal layer which is fixed between a main metal layer formed of a metal having a smaller linear expansion coefficient than copper and one main surface of the main metal layer and the other main surface of the semiconductor chip. And a second copper layer fixed to the other main surface of the main metal layer. The average thickness of the solder for fixing the semiconductor chip and the header is 2/3 or more of the thickness of the semiconductor chip.

In another example of the present invention, the metal laminated body is fixed between the semiconductor chip and the bowl-shaped electrode instead of forming the bowl-shaped electrode.

[0007]

[Action]

 Since the main metal layer of the metal laminate has a small linear expansion coefficient, the thermal stress caused by the difference in linear expansion coefficient between the bowl-shaped electrode and the semiconductor chip is relieved. Further, since the average thickness of the solder interposed between the semiconductor chip and the header portion is ⅔ or more of the thickness of the semiconductor chip, the thermal stress caused by the difference in linear expansion coefficient between the lead and the semiconductor chip is Is alleviated.

[0008]

【Example】

 An embodiment of a semiconductor device according to the present invention applied to an output rectifying diode of an automobile alternator will be described below with reference to FIGS. In these drawings, the same parts as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

As is apparent from FIG. 1 showing the first embodiment of the present invention, the bowl-shaped electrode (2) which also functions as a heat sink is composed of a metal laminated body (copper clad iron) consisting of three layers. This metal laminate has a main metal layer (8) made of iron having a smaller linear expansion coefficient than copper, one main surface of the main metal layer (8) and the other side of the diode chip (semiconductor chip) (1). A first copper layer (7) fixed to the main surface of the solder by a solder (5) and a second copper layer (9) fixed to the other main surface of the main metal layer (8). To be done.

Further, the thickness of the pad (6) for fixing the diode chip (1) and the header portion (3a) of the lead (3) to each other is ⅔ or more of the thickness of the diode chip (1). For example, the thickness of the diode chip (1) is 185 μm, and the thickness of the solder (6) is 150 μm. The main metal layer (8) may be an iron-based alloy layer called Invar or Kovar. The lead (3) is a rod-shaped copper lead plated with Ni (nickel).

In this embodiment, since the main metal layer (8) has a small coefficient of linear expansion, the coefficient of linear expansion of the bowl-shaped electrode (2) and the diode chip (1) is larger than that of a conventional heat sink made of only copper. The thermal stress of the diode chip (1) caused by the difference is relieved, and the damage of the diode chip (1) can be prevented.

As is apparent from FIG. 2 showing the second embodiment of the present invention, a copper clad iron tab (metal) composed of three layers between the copper bowl-shaped electrode (2) and the diode chip (1). The laminate (13) is fixed. The tab (13) includes a first copper layer (10) fixed to the diode chip (1) by solder (5), a main metal layer (11) fixed to the first copper layer (10), A second copper layer (12) fixed to the main metal layer (11) and fixed to the bowl-shaped electrode (2) by solder (5) is provided.

The thickness of the pad (6) for fixing the header portion (3a) of the lead (3) and the diode chip (1) is ⅔ or more of the thickness of the diode chip (1). In this embodiment, the diode chip (1) has a thickness of 185 μm and the solder (6) has a thickness of 150 μm.

In this embodiment, a tab (13) having a linear expansion coefficient close to that of the diode chip (1) is fixed between the bowl-shaped electrode (2) and the diode chip (1). Therefore, the thermal response given to the diode chip (1) by the bowl-shaped electrode (2) due to the difference in linear expansion coefficient is mitigated by the tab (13). Further, since the thickness of the solder (6) is 2/3 or more of the thickness of the diode chip (1), the thermal stress caused by the difference in linear expansion coefficient between the lead (3) and the diode chip (1) is relaxed. To be done.

The embodiment of the present invention is not limited to the above-mentioned embodiment, and can be modified. For example, as shown in FIG. 3, an annular protrusion may be provided on the header portion inside the outer edge of the semiconductor chip to secure the solder thickness.

[0016]

[Effect of device]

 According to the present invention, the thermal stress caused by the difference in linear expansion coefficient between the bowl-shaped electrode and the lead and the semiconductor chip can be relaxed, and the semiconductor chip can be prevented from being damaged by the thermal stress. It is possible to significantly extend the life of the device.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention applied to a rectifying diode.

FIG. 2 is a sectional view showing a second embodiment of the present invention applied to a rectifying diode.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view of a conventional rectifying diode.

[Explanation of symbols]

(1). ． ． Diode chip (semiconductor chip),
(2). ． ． Bowl-shaped electrode, (3). ． ． Reed,
(Four). ． ． Protective resin, (5) (6). ． ． solder,
(7) (10). ． ． First copper layer, (8) (11). ． ． Main metal layer, (9) (12). ． ． Second copper layer, (1
3). ． ． Tab (metal laminate),

Claims (2)

[Scope of utility model registration request] 1. A semiconductor chip, a lead having a header portion fixed to one main surface of the semiconductor chip by soldering, a bowl-shaped electrode fixed to the other main surface of the semiconductor chip, and the bowl shape. In a semiconductor device provided with a protective resin filled in an electrode and sealing the inside of the semiconductor chip and the lead, the bowl-shaped electrode is composed of a metal laminated body, and the metal laminated body has a linear expansion coefficient of copper. Of the main metal layer, a first copper layer fixed between one main surface of the main metal layer and the other main surface of the semiconductor chip, and the other of the main metal layers A second copper layer adhered to the main surface of the semiconductor chip, and the average thickness of the solder for adhering the semiconductor chip and the header is 2/3 or more of the thickness of the semiconductor chip. Semiconductor device. 2. A semiconductor chip, a lead having a header portion fixed to one main surface of the semiconductor chip by soldering, and the other main surface side of the semiconductor chip are electrically connected via a metal laminate. In a semiconductor device comprising a bowl-shaped electrode, and a protective resin filled in the bowl-shaped electrode and sealing the inside of the semiconductor chip and the lead, the other main surface of the semiconductor chip and the bowl-shaped electrode The metal laminated body fixed between the main metal layer formed of a metal having a smaller linear expansion coefficient than copper, and one main surface of the main metal layer and the other main surface of the semiconductor chip. A first copper layer adhered to the first metal layer and a second copper layer adhered between the other main surface of the main metal layer and the bowl-shaped electrode, and between the semiconductor chip and the header. The average thickness of the intervening solder is equal to the thickness of the semiconductor chip. / Wherein a 3 or more.