JPH11163211A - Electronic component, printed board, and checking method for printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable circuits and parts mounted on a printed board in which electronic components such as semiconductor devices mounted thereon to be enhanced in mounting density. SOLUTION: Plural lead terminals 2 are formed on the four sides of a plate- like body 3 of a semiconductor device 1, and all the lead terminals 2 are partly arranged on the same plane as with one surface of the body 3. The one surface of the body 3 comes into contact with the printed board is to become the semiconductor device 1 mounted on a printed board. Check pads 4 are formed on both the opposite sides of the body 3, where one of the opposite sides of the body 3 comes into contact with the printed board. The semiconductor device 1 is equipped with signal wires, and the signal wires are each electrically connected to corresponding check pads 4 inside the semiconductor device 1. After the semiconductor device 1 has been mounted on the printed board, a current is made to flow through the circuit of the printed board via the check pads 4 so as to check the printed board. Since checking pads are not formed on a printed board, circuits and parts mounted on the printed board can be made high in density in mounting density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic component mounted on a printed circuit board, a printed circuit board on which the electronic component is mounted, and a method of inspecting the printed circuit board.

[0002]

2. Description of the Related Art In recent years, the opportunity to use not only the information processing field but also a personal computer has been generally widened, and personal portable terminals have now become widespread.
In particular, in the market, when a portable terminal is smaller in size than a notebook personal computer, portability such as insertion into a pocket is often emphasized. In addition, the functions and performance of the portable terminal are required to have more capabilities than conventional personal computers.

[0003] In order to meet the above-mentioned demands, the mounting of components on a printed circuit board has to be increased.
Therefore, the density of components mounted on a printed circuit board often makes a trade-off between the valuable area of the printed circuit board and its performance and function.

Conventionally, conductive test pads are formed on a printed circuit board in order to test the function and performance of the printed circuit board on which electronic components such as semiconductor devices are mounted. In the printed circuit board on which the inspection pads are formed, at the time of designing the printed circuit board, a part of wiring connecting between a plurality of electronic components mounted on the printed circuit board is extended, and the extended wiring and the inspection pad are used. Are electrically connected. In such a printed circuit board, the printed circuit board is inspected by bringing test pins into contact with the test pads of the printed circuit board and flowing current through the circuit of the printed circuit board through the test pads.

[0005]

However, on a conventional printed circuit board on which electronic components are mounted, inspection pads that are not normally used except for inspection are formed as components, and the inspection pads are printed. There is a problem that it becomes a restriction when increasing the density of components and circuits on the substrate.

In addition, since the inspection pads are arranged as components on the printed circuit board at the stage of designing the printed circuit board, when the printed circuit board is redesigned, the inspection pads must be newly arranged again, which takes time. Is a problem.

An object of the present invention is to provide an electronic component mounted on a printed circuit board so as to increase the density of circuits and components on the printed circuit board, and a printed circuit board capable of increasing the density of circuits and components. And a method of inspecting the printed circuit board.

[0008]

In order to achieve the above object, the present invention relates to an electronic component having a plurality of signal lines and mounted on a printed circuit board. A plurality of conductive test pads electrically connected to each of the plurality of signal lines are formed on the surface opposite to the surface to be formed.

As described above, by forming a plurality of test pads on the surface of the electronic component opposite to the surface on the printed circuit board side, the plurality of test pads and the signal lines of the electronic component are interposed. Then, a current is supplied to the circuit of the printed circuit board to inspect the printed circuit board. In this case, since the inspection pads are not formed on the printed circuit board, it is possible to increase the density of circuits and components on the printed circuit board as compared with the conventional case where the inspection pads are formed on the printed circuit board.

A printed board according to the present invention has the electronic component according to the above-mentioned invention mounted thereon. In such a printed board, it is not necessary to form an inspection pad on the printed board as described above, and the density of circuits and components on the printed board can be increased.

Further, the method for inspecting a printed circuit board according to the present invention has a plurality of signal lines. Forming a plurality of conductive test pads electrically connected to each of the lines; mounting the electronic component on a printed circuit board; and via the plurality of test pads of the electronic component. Applying a current to the printed circuit board and inspecting the printed circuit board.

In the above-described method of inspecting a printed board, similarly to the above, an inspection pad electrically connected to a signal line is formed on an electronic component, and the printed board is connected to a circuit via the inspection pad. Since the current flows, there is no need to form an inspection pad on the printed board, and the density of circuits and components on the printed board can be increased.

Preferably, a semiconductor device is used as the electronic component.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an electronic component according to an embodiment of the present invention. As shown in FIG. 1, a QFP (quad flat package) type semiconductor device 1 is used as an electronic component of the present embodiment. In the semiconductor device 1, a plate-shaped main body 3 in which a silicon chip is covered with a mold member is provided.
A plurality of lead terminals 2 are formed on the four side surfaces.
The plurality of lead terminals 2 are all bent in an L shape, and a part of all the lead terminals 2 is arranged in the same plane as one surface of the main body 3. One surface of the main body 3 is a surface on the printed circuit board side when the semiconductor device 1 is mounted on the printed circuit board.

A plurality of inspection pads 4 are formed on the surface of the main body 3 opposite to the surface on the printed circuit board side. The plurality of inspection pads 4 are arranged in a matrix. The semiconductor device 1 has a plurality of signal lines, and each signal line of the semiconductor device 1 and a test pad 4 corresponding to each signal line are electrically connected inside the semiconductor device 1. .

The inspection pads 4 are for inspecting the printed board when the semiconductor device 1 is mounted on the printed board. The printed circuit board is inspected by bringing the test pins 5 into contact with the test pads 4 and applying a current to the semiconductor device 1 and the printed circuit via the test pins 5 and the test pads 4.

FIG. 2 is a diagram for explaining a method of inspecting a printed circuit board on which the semiconductor device 1 is mounted. As shown in FIG. 2, the semiconductor substrate 1 is mounted on the component surface of the printed circuit board 5. In this case, the inspection pad 4 shown in FIG. 1 is located on the surface of the main body 3 opposite to the printed circuit board 5 side. Then, the test pins 6 are brought into contact with the test pads 4 from the side of the semiconductor device 1 side of the printed circuit board 5, and current is applied to the semiconductor device 1 and the circuit of the printed circuit board 5 via the test pins 6 and the test pads 4. Shed. In this way, the inspection of the semiconductor device 1 and the printed board 5 is performed. The method of inspecting the printed circuit board 5 differs from the conventional method of inspecting a printed circuit board only in that the inspection pads are not formed on the printed circuit board but on the semiconductor device 1. Not. Therefore, an apparatus used for inspection of a conventional printed circuit board can be used as it is.

FIG. 3 is a plan view showing the semiconductor device 1. FIG. 4 is a plan view showing the inspection pad 4 formed on the semiconductor device 1.
It is a figure for explaining arrangement of. Semiconductor device 1
, A total of 256 lead terminals 2 are formed, and the lead terminals 2 are arranged on the side surface of the main body 3 at a pitch of 0.4 mm. As shown in FIG.
The shape of the main body 3 is rectangular. Length A of one side of body 3
Is 27.85 mm, and the length B of the side orthogonal to that side is
Is 27.05 mm. As shown in FIG. 4, the shape of each test pad 4 is circular,
Has a diameter D of 1 mm. The pitch P of the inspection pads 4 is 1.5 mm. Thus, the body 3
By arranging the test pads 4 on the surface opposite to the surface on the side of the printed circuit board 5, 16 test pads 4 are arranged vertically and 16 horizontally, and a total of 256 test pads 4 are arranged. It can be formed in the semiconductor device 1.

In the above case, the area occupied by the plurality of test pads 4 in the semiconductor device 1 is 1.5 × 15 + 1 = 2.
This corresponds to an area of a square having 3.5 mm on one side, and the area is 23.5 × 23.5 = 552.25 mm ² . Accordingly, in this case, the area of the printed circuit board 5 is reduced by 552.25 mm ² .

As described above, in the semiconductor device 1 as an electronic component of the present embodiment, the inspection pads 4 are formed on the surface of the semiconductor device 1 opposite to the surface on the printed circuit board 5 side. Then, the printed board 5 on which the semiconductor device 1 is mounted is inspected by bringing the test pins 6 into contact with the inspection pads 4. Therefore, no test pad is formed on the printed board 5 and there is no need to provide an area for the test pad on the printed board 5, so that the density of circuits and components on the printed board 5 can be increased. Further, when designing the printed circuit board 5, it is not necessary to design such that the inspection pads are arranged on the printed circuit board as in the related art, so that the design of the printed circuit board 5 is simplified, and Time is reduced. Further, when the printed circuit board 5 is redesigned, similarly, unlike the conventional printed circuit board, it is not necessary to redesign the arrangement of the test pads, and the redesign time of the printed circuit board 5 can be reduced. Is done.

Although a QFP type semiconductor device is used as the electronic component of this embodiment, a QF type semiconductor device is used instead of the QFP type semiconductor device.
J (quad flat J-lead) type, BGA (ball grid arra)
y) type or SOP (small outline non-leaded) type may be used. In the present embodiment, the test pad is formed on the semiconductor device. However, the test pad may be formed on another electronic component instead of the semiconductor device. In that case, any electronic component may be used as long as the surface of the electronic component opposite to the surface on the printed circuit board side has an area where an inspection pad can be formed.

[0023]

As described above, according to the present invention, an electronic component mounted on a printed circuit board is provided on a surface opposite to the surface on the printed circuit board side, which is electrically connected to a signal line of the electronic component. Since the test pads are formed and the test pads are not formed on the printed circuit board, the density of circuits and components on the printed circuit board can be increased. Therefore, by using a high-density printed circuit board for an electronic device such as a portable terminal, there is an effect that an electronic device that is small and has high performance can be obtained. Further, since no inspection pad is formed on the printed circuit board, the design of the printed circuit board is simplified, and the time required for designing the printed circuit board can be shortened. Further, even when the printed circuit board is redesigned, there is no need to redesign the arrangement of the inspection pads, so that the time required for redesigning the printed circuit board can be shortened.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an electronic component according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of inspecting a printed circuit board on which the semiconductor device shown in FIG. 1 is mounted.

FIG. 3 is a plan view showing the semiconductor device shown in FIG. 1;

FIG. 4 is a diagram for explaining an arrangement of test pads formed on the semiconductor device shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Lead terminal 3 Main body 4 Inspection pad 5 Printed circuit board 6 Test pin

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/00 G01R 31/28 U

Claims (6)

[Claims] An electronic component having a plurality of signal lines and mounted on a printed circuit board, wherein the plurality of signal lines are provided on a surface opposite to a surface on the printed circuit board side when mounted on the printed circuit board. An electronic component, comprising a plurality of conductive test pads electrically connected to respective lines. 2. A printed circuit board on which the electronic component according to claim 1 is mounted. 3. The printed circuit board according to claim 2, wherein a semiconductor device is used as said electronic component. 4. An electronic component, having a plurality of signal lines, mounted on a printed circuit board, and having an electrical surface corresponding to each of the plurality of signal lines on a surface opposite to a surface on the printed circuit board side. Forming a plurality of conductive test pads connected to the printed circuit board; mounting the electronic component on the printed board; flowing a current through the printed board via the plurality of test pads of the electronic component. Inspecting the printed circuit board. 5. The printed circuit board inspection method according to claim 4, wherein the inspection pads are formed by the number of specific signal lines required for the inspection of the printed circuit board. 6. The method according to claim 4, wherein a semiconductor device is used as the electronic component.