JPH02172266A - Lead, package and electric circuit device - Google Patents

Abstract

PURPOSE:To enable highly reliable mounting, and increase mounting density by providing an outer lead part with a bonding material protrusion protecting means, which outer lead part is bonded to a specified conductor via bonding material. CONSTITUTION:A lead 4 is constituted of an inner lead part 4a and an outer lead part 4b which is bonded to a specified conductor 2 via bonding material 3. The outer lead part 4b is provided with a penetrating hole 12, so that solder gets into the penetrating hole 12 even when the solder is inclined to protrude from the conductor pattern 2. As a result, the squeeze-out of the solder 3 can be prevented while sufficient bonding strength is kept, and the short between adjacent patterns 2 can be excluded. The distance between adjacent outer lead parts 4b can be reduced. Thereby, highly reliable mounting is enabled, and mounting density can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to leads, packages, and electric circuit devices.

BACKGROUND OF THE INVENTION Conventional techniques for semiconductor devices include those that make full use of thick film technology, thin film technology, resin encapsulation, bonding, and the like.

Therefore, for example, a semiconductor device using a surface mounting method called a so-called flat back type will be described. This is to increase the mounting density on the printed circuit board. For example, the opening of the terminal protruding from the mold resin such as epoxy resin (outer lead part 4b to be described later) is narrowed, and this terminal is placed in the mold resin. It is of a type that is exposed on the opposite sides (or four sides) and attached flat to the printed circuit board 1, as shown in FIGS. 11 and 13, which will be described later.

That is, for example, as shown in FIG. 13, the lead 4 provided in the package 5 consists of an inner lead part 4a and an outer lead part 4b. The inner lead portion 4a connects the semiconductor element 7 to a pad 8 on a semiconductor element (for example, an IC chip including a dynamic RAM, etc.) 7 mounted on a mount 10 by a bonding wire (for example, gold) 9.
The entire structure is molded with resin (for example, epoxy resin) 6 by transfer molding.

Further, the outer lead portion 4b has a thickness of, for example, 0.15 m.
, 1pJA0.35mm, soldering part length 1.0
mm, and is formed into a bent state as shown in FIGS. 11 and 12. Then, the end part is a Cu conductor pattern 2 (thickness Q, 05 mm) on the printed circuit board 1.
, width 0.4 mm), and are electrically connected and fixed, for example, by solder 3. Further, the interval between adjacent outer lead portions 4b is, for example, /1.0ma+
zJ, and although the entire Bakucage 5 is not shown,
In this example, the outer lead portion 4b (!) of the opposing side (see FIG. 12) has a total of 38 pins L each with K/19 pins I.
A J-dore 4) is provided in the package 5. Each outer lead portion 4b is fixed and electrically connected onto the semiconductor element 7 and the conductive pattern 2 on the printed circuit board 1 as described above. The width of the pattern 2 in the area where the outer lead portion 4b is fixed is, for example, 10,4rrm/I, and the distance between adjacent patterns 2 is, for example, 10.2 mmJ.

As explained above, when considering the case where the package 5 is mounted on the printed circuit board 1, the distance between the adjacent outer lead parts 4b is very narrow at 70.3 mm7.
Furthermore, the distance between the conductor patterns 2 on the printed circuit board 1 to which the respective outer lead portions 4b are fixed is also 2 mm.
1, which is very narrow.

Therefore, during soldering, for example, the solder 3 may protrude from the predetermined pattern 2, as shown in FIGS. Sim )) L, there is a problem that it gets lost. In other words, the mounting yield will be significantly reduced.

Furthermore, in order to solve this problem, it is necessary to increase the distance between adjacent outer lead portions 4b of the package 5 and the distance between adjacent conductor patterns 2 on the printed circuit board 1. This is particularly inconvenient in today's electrical circuit devices that require high-density packaging.

C. OBJECTS OF THE INVENTION An object of the present invention is to provide a lead, a package, and an electric circuit device that can be mounted with high reliability and that can also improve packaging density.

2. Structure of the invention, that is, the present invention has an inner lead portion and an outer lead portion that is bonded to a predetermined conductor via a bonding material, and the outer lead portion is provided with means for preventing the bonding material from protruding. This is related to the lead that is currently in use.

Further, the present invention includes an electrical component, an inner lead portion to which the electrical component is connected, and an outer lead portion that is bonded to a predetermined conductor via a bonding material, and prevents the bonding material from protruding into the outer lead portion. A package is also provided in which the means are provided.

Furthermore, the present invention provides a package that includes an electrical component, an inner lead portion connected to the electrical component, and an outer lead portion bonded to a predetermined conductor via a bonding material, the outer lead portion being bonded to the conductor. The present invention also provides an electric circuit device in which at least one of the outer lead portion and the conductor is provided with a means for preventing extrusion of the bonding material in the bonding region.

E, Example The present invention will be explained in detail below.

1 to 4 show a first embodiment of the present invention. However, parts similar to those in the example shown in FIGS. 11 to 13 described above are given the same reference numerals, and their explanations may be omitted.

According to this example, the configuration that is significantly different from the examples shown in FIGS. 11 to 13 is that the thickness is o, 15 cm, and the width is 0.
In each outer lead portion 4b of 35M, a vertical lO,
4trm4, horizontal 10.15mm4 rectangular through hole 12
are provided by etching. That is, although not shown, in this example, F3 El
There is a pin lead 4, and each outer lead part 4
A through hole 12 is provided in each of b. This through hole 12
may be formed by etching or punching during lead frame molding. The material of the lead 4 in this example is F.
It is an e-Ni alloy (42 alloy alloy). Also, the external dimensions of package 5 are 120 mm long, 14 liters wide, and thick! It is 2.0 Peng.

Next, to explain the printed circuit board 1, C is coated on an insulating substrate (for example, phenol resin) 1 by a known method.
r% Cu and Au are laminated in this order by vacuum evaporation, and patterning is performed to form a predetermined conductor pattern 2. Note that this conductor pattern 5-/2 has a thickness ffO, a width of 05 mm and a width fO, respectively, with respect to the outer lead portion 4b described above.
4, and the distance between adjacent patterns 2 is 1.
It is 0.2 mm1. The wiring width of conductor pattern 2 is lO, 4Mm/! It is. Then, a solder film 3 having a thickness of 10.2 ml is formed in the bonding area 20 on the conductive pattern 2 by screen printing. And the atmosphere! Temperature f250'C under nitrogen l? As shown in FIGS. 2 and 3, the outer lead portion 4b of the package 5 is bonded to the printed circuit board 1 as shown in FIGS.
Solder the upper conductor pattern 21C.

As explained above, according to the lead 4 and package 5 according to this embodiment, the through hole 1 is provided in the outer lead portion 4b.
2, as shown in Figures 2 and 3,
Even if the solder 3 tries to protrude from the conductor pattern 2, the solder 3 tries to enter the through hole 12, so that the solder 3 can be prevented from protruding while maintaining sufficient bonding strength. Therefore, highly reliable mounting can be performed without adjacent patterns 2 coming into contact with each other. Furthermore, since highly reliable mounting can be performed as described above, the distance between adjacent outer lead parts 4b (leads 4) can be reduced (that is, a desired pitch can be obtained), and the package 5 The package itself can be reduced in size (that is, the packaging density inside the package 5 can be increased). Furthermore, since the distance between adjacent conductor patterns 2 can be reduced,
It is also possible to increase the mounting density on the printed circuit board 1.

Further, since the surface area of the contact portion between the solder 3 and the lead portion 4b is sufficient, there is no problem with the bonding strength.

In addition, until now it has been difficult to visually inspect the wetting properties of solder (see Figure 11), but as shown in Figures 2 and 3 above, the solder 3 passes through the through hole 12 to the outer lead. 4
Since it is protruding from the upper side of b, it is easy to check the solder wetness etc. visually.

Note that FIG. 4 is a sectional view showing a state in which the package 5 is soldered onto the conductive pattern 2. As shown in FIG.

FIG. 5 shows another embodiment of the present invention.
Figure A is a perspective view of the outer lead portion 4b, Figure 5B) 1 Figure 5A (1) A side view on the VB-VB line, and Figure 5C is a vc-v
It is a sectional view taken along the c line.

The difference in this example from the example shown in FIG. 1 above is that the thickness e
: 0.1 tnn in the joint area 20 of the outer lead part 4b of 0.15 mm, width d:o, 55mo+
An elliptical through hole (slot) with a roundness of (longitudinal length a: 0.4 mm, Ill!
b: 0.2M) 32 is provided.

In addition, as shown in Fig. 5B, the longitudinal dimensions of the conductor pattern 2 and the solder [3 are increased by f: approximately 0.4 am on both sides in the figure, and as shown in Fig. 5C. Their widths are the same (or the width of pattern 2 is somewhat smaller than the width of outer lead portion 4b). Note that the other dimension c (length in the longitudinal direction of the outer lead portion 4b in the bonding region 20) is 1.0M.

For each of the dimensions described above, the calculated values of the surface area where the solder wets when the above-described through hole 32 is provided and when the through hole 32 is not provided are shown below.

(Hereinafter, blank space) Note that the above-mentioned bottom surface refers to the contact surface 30 with the solder film 3,
Also, the side surface is the surface 3 in the thickness direction of the outer lead s4b.
1 (including the side surface inside the through hole 32 if there is one). However, it is assumed that the solder does not come into contact with the upper surface of the lead portion 4b.

That is, as mentioned above, when comparing the total surface area, the case based on the present invention has an increase of about 12% compared to the conventional example. Therefore, in addition to having the same advantages as the above-mentioned example, a large surface area can be obtained, and soldering is advantageous in terms of strength. Here, it is generally considered that the strength of soldering increases as the number of menisci on the side surface (the surface in the thickness direction of the outer lead portion 4b) increases more than on the bottom surface (the surface in contact with the solder film 3) 30. The strength of soldering is much greater than that of the conventional method.

FIGS. 6A and 6B show other embodiments of the present invention, in which the shape and number of through holes in the outer lead portion 4b are different from 13 (rectangular) in FIG. 6B
It is modified as shown in 14 (circular) in the figure. That is,
It is clear that these cases also have the above-mentioned advantages, and the contact area between the solder 3 and the lead portion 4b can be made larger.

FIG. 7 shows another embodiment of the present invention, in which, instead of providing a through hole as in the above example, a wavy recess (or day/pull) 15 as shown in the figure is provided. Four of them are provided on the surface of the outer lead portion 4b on the conductor turn 2 side. This can also be done easily by etching, for example, by forming four recesses 15 in a stripe pattern extending perpendicular to the plane of the paper.
Can be formed into a book. Even in this case, the effect of preventing solder from extruding by the recess 15 provides the same advantages as described above, and since the surface area where the solder 3 contacts the outer lead portion 4b increases, the bonding strength also increases.

Also, although not shown, shapes similar to the example of FIG. 7 described above or other shapes (for example, FIG. 1, FIG. 6A, and FIG. 6B)
A concave portion (shaped as shown in the figure) may be provided in the conductive pattern 2 on the printed circuit board 1. This case also has the same advantages as the above example. That is, since the concave portion on the conductor pattern side has the effect of preventing solder from extruding, it is possible to provide an electric circuit device that not only allows highly reliable mounting but also realizes high-density mounting.

Alternatively, in combination with the example shown in FIG. 1, a through hole or a recess may be provided in the outer IJ-do portion and a recess may be provided in the conductor pattern 2 at the same time.

FIG. 8 shows another embodiment of the present invention, in which a wedge-shaped notch 16 as shown in the figure is provided on the side surface and tip of the outer lead portion 4b. That is, in this case as well, since the solder enters into the notch 16, there is an advantage similar to that of the above-mentioned example.

FIGS. 9 and 10 show still another example of the present invention.

In this example, in a mounting structure called a so-called pin-through-hole type, a through hole 18 is formed in a printed circuit board 1 with conductor patterns 2a2b on both sides, and a through hole 18 is formed in the printed circuit board 1, which extends in the vertical direction as shown in the figure. The outer lead portion 17 (corresponding to the above-mentioned 4bK) is inserted and soldered using the solder 3 previously formed on the conductor pattern 2 by screen printing. As shown in the figure, the outer lead portion 17 is provided with a circular through hole 14 similar to that described above in its wide portion. That is, in this example as well, by providing the through hole 14 in the outer lead portion 17, the solder 3 partially enters the through hole 14, so that the spread in the lateral direction is suppressed, and there is an advantage similar to the example described above.

Although the present invention has been illustrated above, the above-mentioned example can be further modified based on the technical idea of the present invention.

For example, the shape of the through-hole of the outer lead portion described above may be triangular, quadrangular, pentagonal, hexagonal, or any other appropriate shape, and the number thereof may be one or more. In addition to etching, a punching method can be used to form the through holes, and in this case, punching up to a diameter of 0.25 m11 is possible.

Further, the shape of the outer lead portion and the recessed portion of the conductor pattern described above may be any suitable shape, and the forming method thereof may be, for example, roughening with a sandblasting method or a cutting tool, or pressing with a punch, in addition to etching. A recessed portion may also be provided. Note that the shape patterns of the through holes and recesses described above do not necessarily have to be the same repeating pattern.

In addition to the solder described above, for example, a conductive adhesive (such as silver epoxy resin) may be used as the bonding material. Further, the solder film 3 on the conductor pattern 2 described above may be formed by, for example, dipping in addition to screen printing, and the through holes 18 in the examples of FIGS. 9 and 10 are plated. It's fine. In the above example, the conductor pattern was formed by vacuum deposition, but sputtering, for example, can also be used. The material of the conductor pattern can also be changed.

In addition, the materials of the leads (inner lead part and outer lead part) are also mentioned above! 4270 I alloy l and 1 other example!
It may be a copper alloy i.

In addition, in the above-mentioned bonding area 20, a bonding material protruding means (through hole or recess) is provided in both the outer lead portion and the conductor.
may be provided.

In addition to the above-mentioned example, the present invention can also be applied to, for example, a TAB type package and a socket for burn-in testing. Even in this case, there will be an inner lead inside the socket and an outer lead outside the socket, which is within the scope of the present invention.

F. Effects of the Invention As described above, the present invention is provided with a means for preventing the bonding material from protruding from the outer lead portion, so that when the outer lead portion is bonded to a predetermined conductor by soldering, for example, adjacent adjacent Highly reliable mounting is possible without connection to other outer leads or conductors. Furthermore, since highly reliable mounting can be performed as described above, the distance between adjacent outer lead portions and between adjacent conductors can be reduced, and the packaging density can also be improved. Therefore, it is possible to provide leads and packages with high reliability and high packaging density. Further, in the bonding area between the outer lead portion and the conductor, at least one of the outer lead portion and the conductor is provided with a means for preventing the bonding material from protruding, so that the same reliability and packaging density as described above can be achieved. We can provide electrical circuit devices.

[Brief explanation of the drawing]

1 to 10 show embodiments of the present invention; FIG. 1 is a partially cutaway perspective view showing the state before the outer lead portion of the flat hack type back cage is joined to the conductor; The figure is a partially cutaway perspective view showing the mounting state after the outer lead part of the flat hack type back cage is joined to the conductor. Figure 3 is an enlarged sectional view taken along the line 11 in Figure 2. Figure 4 is the flat hack type back cage. 5A is a perspective view showing another shape of the through hole of the outer lead portion; FIG. 5B is a side view taken along the line VB-VB of FIG. 5A; Figure 5C is the vc-V of Figure 5A (JIM view, 6th figure, and 6B
The figures are plan views of the main parts showing other shapes of the through-holes in the outer lead part, FIG. 7 is a perspective view of the outer lead part showing other jointing material extrusion prevention means, and FIG. 9 is a pin-through-hole type. 10 is a sectional view taken along the line X--X in FIG. 9. Figures 11 to 13 show conventional examples. Figure 11 is a partially cutaway perspective view showing the state of the flat back after the outer lead portion of the package is joined to the conductor, and Figure 12 is a partially cutaway perspective view of the flat back after the outer lead portion of the package is joined to the conductor. FIG. 11 is an enlarged cross-sectional view taken along the line Xfl-Xll, and FIG. 13 is a cross-sectional view showing the mounting state after the flat pack package is bonded to a conductor. In addition, in the symbols shown in the drawings, 1...... Printed circuit board 2...
・・・・・・・・・ Conductor pattern 3・・・・・・・・・
...Solder (bonding material) 4...Lead 4a...Inner lead part 4b, 17
・・・・・・Outer lead part 5・・・・・・・・・
...Package 6...Mold resin 7...IC chip (electrical component) 9...・ Ponding wire 10...Mount part 12.13.14.32...Through hole (means to prevent bonding material from extruding) 15.16...Concave part or cut Notch portion (bonding material extrusion prevention means) 20...

Claims (3)

[Claims] 1. A lead comprising an inner lead part and an outer lead part joined to a predetermined conductor via a joining material, the outer lead part being provided with a means for preventing the joining material from protruding. 2. It has an electrical component, an inner lead portion to which the electrical component is connected, and an outer lead portion that is bonded to a predetermined conductor via a bonding material, and the outer lead portion is provided with a means for preventing the bonding material from protruding. package. 3. The outer lead portion of the package has an electrical component, an inner lead portion connected to the electrical component, and an outer lead portion bonded to a predetermined conductor via a bonding material. An electric circuit device, wherein at least one of the outer lead portion and the conductor is provided with a means for preventing extrusion of a bonding material.