JPH0821670B2 - Synthetic resin sealed electronic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a so-called synthetic resin-sealed electronic component obtained by encapsulating a portion such as a semiconductor chip with a thermosetting synthetic resin mold body. The present invention relates to a synthetic resin-sealed electronic component configured to be suitable for surface mounting.

[Conventional technology]

Conventionally, in a synthetic resin-sealed electronic component configured to be suitable for surface mounting, each lead terminal is projected from a side surface of a synthetic resin mold body, and a portion of each lead terminal projecting from the mold body is Since the lead body is configured to bend so as to be substantially flush with the bottom surface of the mold body, the area occupied by each lead terminal from the mold body is large, and the mounting density (per unit area of the printed board per printed board) on the printed board is large. There are problems such as hindering the improvement of the number of electronic components that can be mounted and reducing the strength of each lead terminal.

Therefore, JP-A-57-176751 as a prior art discloses that, as shown in FIGS. 25 to 28, a plurality of lead terminals 2, 3, 4 in one electronic component are made of synthetic resin. In the molded body 1, the internal lead terminal portions 2a, 3a, 4a connected to the semiconductor chip 5 and the external lead terminal portions 2b, 3b, 4b to the outside of the molded body 1 are configured, and each external lead terminal portion 2
b, 3b, 4b in the mold body 1, the lower surface 2b ', 3b', 4b 'and the tip end surface of the external lead terminal portions 2b, 3b, 4b.
Only 2b ″, 3b ″ and 4b ″ are the bottom surfaces of the mold body 1.
It is proposed to eliminate the above-mentioned inconveniences by embedding so as to be exposed to the side surface 1a and the side surfaces 1b and 1c.

[Problems to be Solved by the Invention]

Then, in the electronic component in this prior art, the molding of the mold body 1 is performed by connecting the lead terminals 2, 3, 4 with a pair of upper and lower molding dies A, B as shown in FIG. The inner lead terminal portions 2a, 3a, 4a of the terminals 2, 3, 4 and the outer lead terminal portions 2b, 3b, 4b are sandwiched so as to project into the cavity C for molding the body of both molding dies A, B. After that, it is performed by injecting a thermosetting synthetic resin in a molten state into the molding cavitator 1-C at a high pressure.

However, when molding the molded body 1, each of the external lead terminal portions 2b, 3b, 4b of the lead terminals 2, 3, 4 must be in close contact with the inner bottom surface C1 of the molding cavity C. Where it must be, each lead terminal
Since the lead wires 2, 3, 4 are only pressed by the portion outside the molding cavity C, the lead terminals 2, 3, 4,
Lower surface 2b ', 3b', 4 of the external lead terminal portions 2b, 3b, 4b at 4
Between b'and the inner bottom surface C1 of the cavity C,
The molten synthetic resin injected at a high pressure enters the cavity C.

That is, among the external lead terminal portions 2b, 3b, 4b,
The lower surfaces 2b ', 3b', which are exposed from the bottom surface 1a of the mold body 1,
A thin film of synthetic resin is formed on 4b 'when the molded body 1 is formed. In other words, the lower surfaces 2b', 3b ', 4b' of the external lead terminal portions 2b, 3b, 4b are made of synthetic resin. Of the external lead terminal portions 2b, 3b, 4b exposed to the bottom surface 1a of the molded body 1 among the external lead terminal portions 2b, 3b, 4b. On the other hand, in the case of soldering, there is a problem that soldering failure frequently occurs and the solder joint performance is deteriorated.

Moreover, in the electronic component of the prior art, the tip end faces 2b ″, 3b ″, 4b ″ of the external lead terminals 2b, 3b, 4b are made substantially flush with the left and right side faces 1b, 1c of the mold body 1. However, after the molding of the molding body 1, each of the lead terminals 2, 3, 4 is connected to the tip end surface 2b ″, 3b ″, 4 of the external lead terminal 2b, 3b, 4b.
Since it is extremely difficult to cut so that b ″ is substantially flush with the left and right side surfaces 1b, 1c of the mold body 1, the tip end surface 2b ″ of each external lead terminal 2b, 3b, 4b is cut at the time of cutting. Since 3b ″ and 4b ″ are inevitably projected from the side surfaces 1b and 1b of the molded body 1 by a slight dimension, the commercial value is lowered.

Moreover, the tip end surfaces 2b ″, 3b ″, 4b ″ of the external lead terminals 2b, 3b, 4b are made to be substantially flush with the left and right side surfaces 1b, 1c of the mold body 1 as in the prior art. It is difficult to confirm whether or not each external lead terminal portion 2b, 3b, 4b is soldered securely after it is soldered to the printed circuit board. there were.

An object of the present invention is to provide a synthetic resin-sealed electronic component that can solve these problems.

[Means for solving the problem]

In order to achieve this object, the present invention provides that “a plurality of lead terminals are provided in a synthetic resin mold body, the lower surface of the tip of each lead terminal is exposed on the back surface of the mold body, and the tip of each lead terminal is In the electronic component embedded so that the end surface is exposed to the side surface of the mold body, the mold body is provided with a recess means for exposing a part of the upper surface of the tip of each lead terminal. I made it up.

[Functions and effects of the invention]

As described above, when the mold body is provided with the recess means for exposing a part of the upper surface of the tip of each lead terminal, when the mold body is molded by a pair of molding dies, the molding die A protrusion for molding the recess means can be molded in the molding cavity so as to project toward the molding cavity, and each lead terminal is sandwiched by the pair of molds. When attached, each of the lead terminals can be pressed by the protrusion so as to be strongly in close contact with the inner bottom surface of the molding cavity in the molding cavity. Ensure that molten synthetic resin injected at high pressure enters the molding cavity between the lower surface of each lead terminal and the inner bottom surface of the molding cavity. It can be reduced.

That is, it is possible to reduce the formation of a thin film of synthetic resin on the lower surface of each lead terminal during the molding of the mold body, so that it is possible to reliably reduce the occurrence of soldering failure on the printed circuit board. The solder joining performance to the board can be greatly improved.

In addition, as described above, since the mold body is provided with the recess means that exposes a part of the upper surface of the tip of each lead terminal, each lead terminal is When cutting so that the tip end face is substantially flush with the side surface of the mold body, the cutting blade can be inserted into the recessed means, so that each lead terminal is molded by the tip end face. It is extremely easy to cut so that it is flush with the side surface of the body, or it is possible to cut so that the tip end surface is recessed from the side surface of the mold body by a slight dimension, in other words, It is extremely easy to configure the tip end surface of each lead terminal so that it does not protrude from at least the side surface of the mold body, and the commercial value of the electronic component can be reduced. It can be significantly improved without causing a flop.

Furthermore, as described above, since the mold body is provided with the recess means that exposes a part of the upper surface of the tip of each lead terminal, when soldering to the printed circuit board, a part of the solder is , Because it will also adhere to the upper surface of the tip portion of the lead terminal exposed in the recess means, it is extremely easy to confirm whether or not the soldering in each of the lead terminals has been completed, And it will definitely be possible.

In this case, the recess means may be configured by "forming a groove extending from the upper surface of the mold body to a part of the upper surface of the tip portion of the lead terminal" as described in "Claim 2". Or, as described in “Claim 3”,
A molding region defined by a surface parallel to the side surface of the molded body and a surface including the upper surface of the tip portion of the lead terminal is cut out. "
Alternatively, as described in “Claim 4”, “a molding region defined by a surface parallel to the side surface of the mold body and a surface including the upper surface of the tip of the lead terminal is cut off, and , A groove extending from the upper surface of the mold body that remains uncut to a part of the upper surface of the tip of the lead terminal that has not been exposed yet. In the mold,
Molding can be performed in a state where the mold can be easily removed from the mold, in other words, it is possible to prevent the structure of the mold for molding from being complicated due to the mold being removed from the mold.

〔Example〕

Hereinafter, the drawings (FIGS. 1 to 5) when the embodiment of the present invention is applied to a transistor having three lead terminals among various electronic components will be described.

In the figure, reference numeral 10 indicates a synthetic resin-sealed transistor configured to be suitable for surface mounting, and the transistor 10 includes a thermosetting synthetic resin mold body 11 encapsulating a semiconductor chip 15 and the semiconductor. It consists of three lead terminals 12, 13, 14 for the chip 15, and each of the lead terminals 1
2, 13, 14 are internal lead terminal portions 12a electrically connected to the semiconductor chip 15 in the mold body 11,
13a, 14a and the external lead terminal portion 1 outside the molded body 11
It is composed of 2b, 13b and 14b.

Further, the external lead terminal portions 12b, 13b, 14b are provided inside the molded body 11 respectively.
The lower surface 12b ', 13b', 14b 'and the tip end surfaces 12b ", 13b", 14b "at the tip portions of b, 14b are substantially the same as the bottom surface 11a and the left and right side surfaces 11b, 11c of the mold body 11, respectively. It is buried so as to be exposed in a plane.

Then, the left and right side surfaces 11b, 11 of the mold body 11
In c, the grooves 16, 17, and 18, which are the first embodiment of the "recessed means" in the present invention, are provided with the external lead terminal portions 12 described above.
Only at the locations of b, 13b, 14b, the respective grooves 16, 17, 18 are partially provided so as to extend toward the upper surface of the mold body 11, and in the respective grooves 16, 17, 18, the respective External lead terminal part 12b,
The upper surfaces of the tips of 13b and 14b are partially exposed.

The molded body 11 of the transistor 10 thus configured is molded by the transfer method as described below.

That is, as shown in FIG. 6, a lead frame 19 configured so that a plurality of pairs of lead terminals 12, 13, 14 constituting one transistor 10 are formed at a constant interval P is used. As shown in FIGS. 7 and 8, the inner lead terminal portions 12a, 13a, 14 of the lead terminals 12, 13, 14 are formed by a pair of upper and lower molding dies A, B, respectively.
a and the external lead terminal portions 12b, 13b, 14b are
After being sandwiched so as to project into the molding cavity C of the molded body 11 formed on the mating surface of B, the molten synthetic resin is injected into the molding cavity C at a high pressure.

In this case, protrusions C4, C5, C6 for forming the grooves 16, 17, 18 are formed on the inner side surfaces C2, C3 on both the left and right sides of the molding cavity C in the molding cavity C. It is integrally molded so that it projects.

Then, when the lead frame 19 is sandwiched between the molding dies A and B, each of the external lead terminal portions 12b, 13b, and 14b in the lead terminals 12, 13, and 14 is provided with the protrusion C4,
C5 and C6 can press the inner cavity C1 of the molding cavity C so as to come into close contact with the inner bottom surface C1 of the molding cavity C. Therefore, when molding the molding body 11, the external lead terminals are formed. Lower surfaces 12b ', 13b', 14b 'of the parts 12b, 13b, 14b and the inner bottom surface C of the molding cavity C
While the molten synthetic resin injected at a high pressure into the molding cavity C can be surely prevented from entering between the groove 1 and 1, the grooves 16, 17, 18 extend to the upper surface of the mold body 11. To form each groove 16,17,18
By simply molding C4, C5, C6 in the cavity C of one molding die B, the mold body 11 having the grooves 16, 17, 18 can be easily removed from the mold body 11. It is possible to reliably mold in a ready state.

Further, by providing the grooves 16, 17, 18 at the positions of the external lead terminal portions 12b, 13b, 14b on the left and right side surfaces 11b, 11c of the molded body 11, the leads after the molding are formed. When cutting the terminals 12, 13 and 14, the cutting blade can be inserted into the grooves 16, 17 and 18, so that the lead terminals 12, 13 and 14 are external lead terminals. The tip end surfaces 12b ″, 13b ″, 14b ″ of the portions 12b, 13b, 14b are cut so as to be flush with the left and right side surfaces 11b, 11c of the mold body 11, or the external lead terminal portions 12b, As shown in FIGS. 9 and 10, the tip end surfaces 12b ″, 13b ″, 14b ″ of 13b, 14b are recessed from the left and right side surfaces 11b, 11c of the mold body 11 by a slight dimension (δ). It can be reliably and easily cut.

Furthermore, a part of the upper surface of the tip of each of the external lead terminal portions 12b, 13b, 14b is exposed in each of the grooves 16, 17, 18, so that when soldering to a printed circuit board, molten solder is used. Part of the external lead terminal portions 12b, 13b, 14b will also adhere to the upper surface of the tip portion, so that each of the external lead terminal portions 12b, 13b, 14b can be reliably soldered. It will be easier to confirm whether or not it is present.

The groove for the lead terminals 13, 14 adjacent to the corners of the molded body 11 in plan view among the lead terminals 12, 13, 14 is, as shown in FIGS. 11 to 13, in plan view. Groove with a notched corner in mold body 11
It may be formed into 17a and 18a.

Then, FIGS. 14 to 18 show a second embodiment of the "recess means" in the present invention.

That is, this embodiment is a part of the left and right side surfaces 11b, 11c of the mold body 11 above the upper surface of the external lead terminal portions 12b, 13b, 14b of the respective lead terminals 12, 13, 14; By cutting out the mold area defined by the surfaces 11b ′, 11c ′ parallel to the left and right side surfaces 11b, 11c and the surfaces 20, 21 including the upper surfaces of the tip portions of the external lead terminal portions 12b, 13b, 14b, Each external lead terminal part 12b,
It is configured such that a part of the upper surfaces of the tip portions of 13b and 14b are exposed.

Also in this case, when molding the molded body 11,
As shown in FIG. 19, the surfaces 20, 21 including the upper surfaces of the tip portions of the external lead terminal portions 12b, 13b, 14b are provided in the cavity C for molding the molded body in the pair of molding dies A, B, respectively. The protruding surfaces C7, C8 for forming are formed so as to protrude into the molding cavity C, and the external lead terminal portions 12b, 13b, 14b are formed by the protruding surfaces C7, C8, respectively. Since it is possible to press the inner bottom surface C1 of the molding cavity C strongly in C, the lower surface 12b 'of each of the external lead terminal portions 12b, 13b, 14b at the time of molding the molding body 11. , 13b ', 14b' and the inner bottom surface C1 of the molding cavity C can be surely prevented from invading the molten synthetic resin injected into the molding cavity C at a high pressure, but after the molding. The mold body 11 can be easily demolded.

Further, the "recess means" in the present invention is the grooves 16, 17, 18 and 17a, 18a as in the first embodiment, and the left and right sides of the mold body 11 as in the second embodiment. Surfaces 11b ', 11c' parallel to surfaces 11b, 11c and external lead terminal parts
It is not limited to formation by cutting out the molding region defined by the surfaces 20 and 21 including the upper surfaces of the tip portions of 12b, 13b and 14b, and it is possible to obtain the same as in the third embodiment shown in FIGS. To
The first embodiment and the second embodiment may be combined.

That is, the left and right side surfaces 11b, 11c of the molded body 11
11b ′, 11c ′ parallel to the external lead terminals 12b, 13b, 1
In addition to cutting off the mold area defined by the surfaces 20 and 21 including the upper surface of the tip of 4b, the external lead terminal portions 12b, 13b, 14 are cut off from the upper surface of the mold body 11 that remains uncut.
Groove 16 to part of the top surface of b that is not exposed yet,
It consists of forming 17,18.

Also in this case, when molding the molded body 11, the lower surfaces 12b ', 1 of the external lead terminal portions 12b, 13b, 14b are formed.
It is possible to reliably prevent the molten synthetic resin injected at a high pressure from entering the molding cavity C between the 3b ′ and 14b ′ and the inner bottom surface C1 of the molding cavity C, while the mold after molding is performed. The body 11 can be easily demolded.

Incidentally, each of the above-mentioned embodiments, three lead terminals 12, 13,
Although the case where it is applied to the transistor 10 having 14 is shown, the present invention is not limited to this transistor 10 and other diodes such as a diode having two lead terminals, an IC having four or more lead terminals, a capacitor, etc. It goes without saying that it can also be applied to electronic parts.

[Brief description of drawings]

1 to 24 show an embodiment of the present invention, and FIG.
2 is a plan view of the transistor according to the embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. 1, and FIG. 4 is taken along line IV-IV of FIG. A side view, FIG. 5 is a side view taken along line VV of FIG. 1, and FIG. 6 is a plan view of a lead frame.
FIG. 7 is a vertical sectional front view showing a state in which a molded body of the transistor of the first embodiment is being molded, and FIG.
FIG. 9 is a cross-sectional view taken along line VIII-VIII, FIG. 9 is a plan view of the transistor according to the second embodiment, FIG. 10 is a side view taken along line XX of FIG. 9, and FIG. 11 is a view of the transistor according to the third embodiment. Fig. 12 is a plan view, Fig. 12 is a side view taken along the line XII-XII in Fig. 11, and Fig. 13 is a side view.
FIG. 11 is a side view as seen from XIII-XIII, FIG. 14 is a plan view of the transistor according to the fourth embodiment, and FIG. 15 is XV-XV of FIG.
16 is a sectional view taken along the line X VI-X VI in FIG.
Fig. 14 is a side view taken along the line XVII-XVII in Fig. 14, and Fig. 18 is shown in Fig. 14.
XVIII-XVIII side view, FIG. 19 is a vertical sectional front view showing a state in which a molded body of the transistor of the fourth embodiment is being molded, and FIG. 20 is a plan view of the transistor according to the fifth embodiment, FIG. Fig. 20 is a sectional view taken along line XXI-XXI of Fig. 20,
Fig. 22 is a sectional view taken along the line XX II-XX II in Fig. 20, and Fig. 23 is shown in Fig. 20.
Figure XX III-XX III side view, Figure 24 is XX of Figure 20
IV-XX IV side view, FIGS. 25 to 29 show a conventional example,
Figure 25 is a plan view of the transistor, Figure 26 is X in Figure 25.
X VI-XX VI sectional view, FIG. 27 shows XX VII-XX in FIG. 25
FIG. VII is a cross-sectional view taken along line VII, FIG. 28 is a bottom view of FIG. 25, and FIG. 29 is a vertical cross-sectional front view showing a state where a molded body is being molded. 10 …… transistor, 11 …… mold body, 11a …… bottom surface of mold body, 11b, 11c …… side surface of mold body, 11
b ′, 11c ′ …… A plane parallel to the side surface of the mold body, 12,13,14
...... Lead terminals, 12a, 13a, 14a ...... Internal lead terminal part, 1
2b, 13b, 14b ... External lead terminals, 12b ', 13b', 14b '...
… Underside of tip of external lead terminal, 12b ″, 13b ″, 14b ″
...... External lead terminal end face, 15 …… Semiconductor chip,
16,17,18,17a, 18a …… Groove, 20,21 …… A surface including the upper surface of the tip of the external lead terminal.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Koji Tai 1-7-4 Konan, Minato-ku, Tokyo Inside the Shibaura Technology Center, Sony Corporation (72) Teruyasu Sakurai 1-7-4 Konan, Minato-ku, Tokyo Sony Stock Company Shibaura Technology Center

Claims (4)

[Claims] 1. A plurality of lead terminals in a synthetic resin mold body, the lower surface of the tip of each lead terminal is exposed on the back surface of the mold body, and the tip end surface of each lead terminal is a side surface of the mold body. In the electronic component embedded so as to be exposed to the outside, the mold body is provided with a recess means for exposing a part of the upper surface of the tip portion of each lead terminal. Mold electronic components. 2. The synthetic resin-sealed electronic device according to claim 1, wherein the recess means is formed by forming a groove from the upper surface of the mold body to a part of the upper surface of the tip portion of the lead terminal. parts. 3. The recess means according to claim 1, wherein a mold region defined by a surface parallel to a side surface of the mold body and a surface including an upper surface of a tip portion of the lead terminal is cut out. Synthetic resin encapsulation type electronic component. 4. A mold region defined by a surface parallel to a side surface of a mold body and a surface including an upper surface of a tip portion of a lead terminal according to claim 1, and further, a mold region left uncut. The synthetic resin-sealed electronic component is characterized in that the recess means is formed by forming a groove extending from the upper surface to a part of the upper surface of the lead terminal which is not exposed.