JPS6125255Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the improvement of electronic components, mainly resin-molded semiconductor devices.

Generally, in this type of semiconductor device, as shown in FIGS. 1 to 3, for example, leads B made of lead pieces b ₁ to b ₇ are attached to a heat sink A made of a metal member.
b ₁ and b ₇ are caulked and fixed by the protruding portion C of the heat sink A, and the lead pieces b ₂ to _{b 6} are arranged so as to be spaced apart from each other on the upper surface of the heat sink A. The electrodes of the semiconductor element D fixed in the center and the lead pieces b ₂ to b ₆ are connected with a thin metal wire E, and then,
The main portion including the semiconductor element D is molded and covered with a resin material F.

By the way, the mold coating of the main parts of the heat sink A with the resin material F is done so that the non-fixed side of the semiconductor element D in the heat sink A is in close contact with the upper inner wall surface of the upper mold _G1 , as shown in FIG. 4, for example. The lead B is held between the upper mold _G1 and the lower mold _G2 , and in this state, the resin material F is injected into the cavity formed by the upper mold _G1 and the lower mold _G2 . It is done by

However, when the heat dissipation plate A and the main parts of the semiconductor element D are molded and covered with the resin material F, the lead B is held between a wide area by the upper mold G ₁ and the lower mold G ₂ . However, since the thickness of the lead B tends to vary, it is difficult to always maintain the lead B in close contact with the upper mold G ₁ and the lower mold G ₂ . For example, when the thickness of the lead B changes to a smaller value, a minute gap is formed between the lead B and the upper mold G ₁ and the lower mold G ₂ . In particular, if the resin material has excellent fluidity such as epoxy resin, if the gap is as large as 0.02 mm, it will flow out from the gap along lead B and form a thin film as shown in Figure 5. Resin burrs H are formed. This burr H not only spoils the appearance and reduces the marketability, but also becomes a major obstacle when soldering to the lead B.

Therefore, in the past, burrs were removed using brushing, sandblasting, etc., but when removing burrs, peeling or cracking occurred at the contact boundary between lead B and resin material F, resulting in moisture resistance. The disadvantage is that the character is easily damaged.

In view of these points, the purpose of this project is to provide an electronic component that can significantly improve marketability due to its simple configuration even if a thin resin burr is formed on the lead portion exposed from the resin material. An example of a semiconductor device will be described.

In FIGS. 6 and 7, reference numeral 1 denotes a heat sink made of a metal member with good thermal conductivity, and has protrusions formed at both ends of its upper surface 1a. A lead 2 is composed of a plurality of lead pieces 2 ₁ to 2 ₇ , and the lead pieces 2 ₁ and 2 ₇ are caulked and fixed to the protrusion on the upper surface 1 a of the heat sink ₁ . 2 ₆ are arranged on the upper surface 1a of the heat sink 1 so as to be spaced apart from each other. Thin film-like resin burrs 3 are formed on the parts of these lead pieces 2 ₁ to 2 ₇ that are exposed from a resin material to be described later. 4 is a lead piece 2 ₁ including a resin burr 3
A metal layer formed on the exposed surface of ~ ₂₇ by electroless plating, thermal spraying, spraying, or the like. The metal layer 4 is preferably formed of a solderable metal such as nickel or silver. 5 is the upper surface 1 of the heat sink 1
This is a semiconductor element (component main body) fixed to the center portion in a using a solder member. 6 is lead 2
These are thin metal wires connected to the lead pieces 2 ₂ to 2 ₆ and the electrodes of the semiconductor element 5 . Reference numeral 7 denotes a resin material whose main parts including the heat sink 1 and the semiconductor element 5 are coated with a mold.

As described above, since the metal layer 4 is formed on the parts of the lead pieces ₂₁ to ₂₇ exposed from the resin material 7 after resin molding, the resin burrs 3 are not formed on the surfaces of the lead pieces ₂₁ to ₂₇ . Even if the resin burr 3 is covered with the metal layer 4, the appearance characteristics can be significantly improved without removing the resin burr 3.

Moreover, since the resin burrs 3 on the lead pieces 2 ₁ to 2 ₇ do not need to be removed, deterioration in moisture resistance due to cracks in the resin material 7 can be prevented since they are not removed by sandblasting or the like as in the conventional method.

In particular, when the metal layer 4 is made of a metal with excellent solderability, the soldering process on the surfaces of the lead pieces 2 ₁ to 2 ₇ becomes easy, and the metal layer 4
In addition, since it is also covered with a solder layer, it is possible to prevent the lead pieces 2 ₁ to 2 ₇ from peeling off when they are bent, for example.

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, the electronic components can be applied to capacitors, resistors, etc. in addition to semiconductor devices, and the metal layer can also be formed only on the portion where the resin burr is formed. .
Furthermore, when applied to a semiconductor device, the shape and number of the heat sink and leads can be changed as appropriate.

As described above, according to the present invention, even if a thin resin burr is formed on the lead portion exposed from the resin material, the marketability can be significantly improved by forming the metal layer.

[Brief explanation of the drawing]

Fig. 1 is a broken plan view of the main part of the conventional example, Fig. 2 is a cross-sectional view of Fig. 1, Fig. 3 is a cross-sectional view of Fig. 1, and Fig. 4 explains the mold coating method with resin material. 5 is a bottom view of FIG. 1, FIG. 6 is a cutaway plan view of essential parts showing an embodiment of the present invention, and FIG. 7 is a cross-sectional view of FIG. 6. In the figure, 2 is a lead, 3 is a resin burr, 4 is a metal layer, 5 is a component body, and 7 is a resin material.

Claims (1)

[Scope of utility model registration request] In a product that includes a component body and a lead, and the main part including the component body is molded and covered with a resin material, a metal layer is formed on the exposed surface of the lead and the resin burr of the lead portion exposed from the resin material. Electronic components featuring: