JPH06201793A - Inspecting method for electronic part and circuit substrate mounted with it - Google Patents

Abstract

PURPOSE:To simply and surely detect the open defect of a solder joint part between the lead wire of an electronic part and a wiring pattern on a substrate in a circuit substrate mounted with a plurality of resin package type electronic parts. CONSTITUTION:An electronic part 1 has such characteristics, in the shape of the electronic component having a lead 3 extending from the side of a resin package 2, as a part of the upper face of the inner lead part 3b of the lead 3 is exposed inward from the side edge of a resin package 2. In the case of the inspection of the defect of connection between the lead 3 and a wiring pattern 8 on a substrate 4, measuring probes 11, 11 are severally put between the exposedly shaped inner lead part 3b of the lead 3 and the pattern 8 on the substrate to be connected with the lead 3, and the defect of connection can be easily and surely inspected by carrying electric current between the probes 11, 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component and a method of inspecting a circuit board on which the electronic component is mounted. The circuit board formed by mounting a plurality of electronic components by soldering has an open / short test or a function test. The present invention relates to a device that can be performed more simply and efficiently.

[0002]

2. Description of the Related Art For example, a hybrid IC is formed by mounting a plurality of electronic components on a substrate having a predetermined wiring pattern. Such a hybrid IC constitutes a specific circuit so as to achieve a certain function as a whole. The circuit board that constitutes such a hybrid IC is subjected to an open / short test or a function test before shipment. The open / short inspection is to inspect whether or not the solder joint between the lead of the electronic component mounted on the board by the soldering process and the wiring pattern on the circuit board to which this is soldered is properly performed. It is a thing. The function test is to check whether or not a circuit composed of a plurality of electronic components functions properly.

By the way, as a typical electronic component mounted on a substrate to form a hybrid IC or the like, there is a resin package type semiconductor device such as IC or LSI.

A conventional general form of this type of resin package type semiconductor device a is as shown in FIG. What is shown in FIG. 9 is a so-called surface mount type resin package type semiconductor device. In this semiconductor device a, a predetermined number of leads c bent in a crank shape are extended from both side surfaces of a resin package b having a predetermined thickness and a rectangular shape in plan view. Such a form of the crank-shaped lead is formed so as to be suitable for surface mounting on the board d, and a horizontal portion c ′ in contact with the board d is formed at the end portion of each lead c. Has been done.

The semiconductor device a is mounted on the substrate d by a so-called reflow soldering method.
That is, cream solder is printed and applied to a predetermined portion on the wiring pattern e of the substrate d, and the semiconductor device a is printed and applied to a predetermined portion on the substrate, that is, the lower end horizontal portion c ′ of the lead c. It is placed on the cream solder so that the whole substrate is passed through a heating furnace and cooled. Then, the solder component f in the cream solder melts and cools and solidifies, so that the lead c and the wiring pattern e on the substrate d are electrically joined.

When a large number of electronic components a mounted on the substrate d are provided as described above and a hybrid IC is formed so as to achieve a certain function as a whole, the electronic components a of each electronic component a are formed. It is extremely difficult to inspect whether the lead c is properly electrically connected to the wiring pattern e on the substrate d. Such an open / short inspection is generally performed by bringing the two measuring probes g, g into contact with conductor portions sandwiching the solder joint. However, the method of bringing the measurement probe g into contact with the lower end horizontal portion c ′ of the lead c as shown in FIG. 10 is not suitable. This is because, even if the lead c is lifted from the pattern e of the substrate d and correct electrical connection is not made, when the lead c is pressed from above by the probe g, the lead c and the pattern e on the substrate This is because the connection is made and eventually the open state cannot be detected. Therefore, in the conventional electronic component such as a semiconductor device having a general configuration as shown in FIG. 9, the open / short test by bringing the probe g into contact with the lead c cannot be established.

Therefore, in order to inspect the circuit board d on which a large number of conventional electronic components a are mounted, a predetermined check point is provided on the wiring pattern e formed on the circuit board d, and a measurement probe is provided on this. There is no choice but to use the measurement method of contacting with.

In this case, there are mainly the following two problems. The first is to analyze the circuit inside the semiconductor device a such as an IC, and then contact the measurement probes g, g between the wiring patterns to which the leads connected to both poles of the specific element are connected,
It is unavoidable to perform the open test of the lead depending on whether the parasitic diode of the internal element works, but in this case, even if the open state is detected, whether the positive electrode or the negative electrode for inspecting the internal element is used. It is not possible to determine whether the connected leads are open or not, and further inspection such as visual inspection is required, which ultimately makes the inspection very complicated.

Secondly, as described above, the lead c of the electronic component is used.
Since the measurement probe cannot be directly brought into contact with the circuit board, it is necessary to provide check points on the pattern on the circuit board, which increases the amount of wasted space on the circuit board and hinders downsizing of the entire board.

Further, when the circuit becomes complicated and the number of elements in the semiconductor device is large and the number of leads extending from one semiconductor device is large, the parasitic diode of the internal element as described above functions. In some cases, the inspection cannot be performed for all the leads depending on whether or not it is possible, and in this case, a very complicated operation such as an inspection by an expensive and large-scale optical inspection manual becomes necessary.

The present invention has been devised under the above circumstances, and in a circuit board on which a plurality of resin package type electronic parts are mounted, the connection between the electronic parts and the circuit board is made. Its purpose is to make the check easier and more efficient.

[0012]

In order to solve the above problems, the present invention takes the following technical means.

That is, the invention described in claim 1 of the present application is an electronic component to be mounted on a certain substrate to form a hybrid IC, in which leads are extended from the side surface of the resin package. And a part of the upper surface of the inner lead portion of the lead is exposed inward from the side edge of the resin package.

The invention according to claim 2 of the present application is a method for inspecting a circuit board configured by mounting the electronic component according to claim 1 by soldering. It is characterized in that a measurement probe is brought into contact with the exposed inner lead portion and the exposed inner lead portion of the wiring pattern or other electronic component on the circuit board.

[0015]

The electronic component of the present invention has a form in which the leads are extended from the side surface of the resin package, and a part of the upper surface of the inner lead portion of the lead is more than the side edge of the resin package. It is exposed inward. The measurement probe is brought into contact with the exposed upper surface of the inner lead. This inner lead
Since it is exposed inward from the side edge of the resin package, even if the measuring probe is brought into contact with this inner lead, external force does not act on this particular lead to bend it. In other words, in the past, when the measurement probe was brought into contact with the lead itself, even if the lead had an open defect that floated from the substrate,
This lead is forcibly pressed onto the substrate by the contact of the measurement probe, so to speak, there is a problem that the open defect is cured at the time of contacting the probe, but in the case of the electronic component of the present invention Has
Although the measurement probe can be directly contacted with the lead,
Since the contact is made at an inner portion of the side edge of the resin package, an external force unlike the conventional case does not act on the lead portion extending from the resin package.

Therefore, in the circuit board on which the electronic component of the present invention is mounted, the exposed inner lead of each lead and the wiring pattern on the board to which each lead is to be soldered are brought into contact with the measurement probe. Therefore, it is possible to reliably detect the open defect between the lead and the wiring pattern on the substrate.

In the prior art, it was not possible to directly contact the measuring probe with the leads. Therefore, by analyzing the circuit in the electronic component, a pair of leads that conduct to both electrodes of the internal element should be soldered. There was no choice but to detect the open defect of the lead depending on whether the parasitic diode of the element can function by contacting the measurement probe on the above, but according to the present invention, the circuit analysis as described above is completely unnecessary, Moreover, it has become possible to inspect all the leads for open defects on the circuit board reliably and easily.

In some cases, when the leads of the two electronic components having the embodiment of the present invention should be conducted through the wiring pattern on the substrate, the measuring probe should be brought into contact with the inner leads of the leads. Thus, the open defect of each lead can be detected without providing a measurement point on the wiring pattern on the substrate.

As described above, according to the present invention, in a circuit board such as a hybrid IC formed by mounting a plurality of resin package type electronic parts, a connection failure between the lead and the wiring pattern on the board is surely ensured. In addition, it becomes possible to perform an inspection easily.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an overall perspective view of an embodiment of an electronic component 1 of the present invention, and FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

This electronic component 1 is a resin package type I
C, which has an oblong rectangular shape in plan view and has a plurality of leads 3 from both sides of the resin package 2 having a predetermined thickness
Is extended. The lead 3 is formed in the electronic component 1 as a so-called internal mounting type. That is, each lead 3 is bent downward after reaching the package side edge in the inside of the resin package 2 in the horizontal direction, and is bent outward in the horizontal direction at the lower end of the downward bent portion. The horizontal bent portion 3a is a portion to be connected to the board 4 by solder. Then, the position of the horizontal bent portion 3a is substantially the same height as the lower surface of the resin package 2.

As shown in FIGS. 1 and 2, in the electronic component 1 of the present invention, the upper surface of the inner lead portion 3b of each lead 3 (the portion located inside the side edge of the resin package 2). However, it is exposed. In the example of FIGS. 1 and 2, the resin package in the conventional resin package type electronic component is formed by removing the upper portion of the lead 3 from the side in a L-shaped cross section over a predetermined width. The upper surface of the portion 3b is exposed.

The electronic component having the structure shown in FIG. 2 can be manufactured by following the conventional method of manufacturing a semiconductor device. That is, the semiconductor chip 5 is bonded to a predetermined portion of the lead frame, the upper surface pad of the semiconductor chip and each inner lead portion 3b are connected by wire bonding, and the bonding chip, the bonding wire 6 or the inner lead 3 is thus connected. The portion 3b is wrapped with a thermosetting resin to form the resin package 2. Then, the lead and the lead frame are separated and each lead is formed into a predetermined shape.

Conventionally, in the molding process for forming the resin package described above, cavities which are substantially equal to each other are formed in the upper mold and the lower mold, but when forming the resin package 2 as shown in FIG. The upper mold cavity is slightly modified as compared with the conventional one. That is, the electronic component of the present invention can be easily implemented only by modifying the cavity shape of the upper mold used in the resin molding process.

The method of exposing the upper surface of the inner lead portion 3b of each lead 3 is as shown in FIGS. 1 and 2, and as shown in FIG. 5, the inner lead portion 3b is formed on the upper surface of the resin package. The hole 7a reaching the upper surface is provided,
As shown in FIG. 4, a groove 7a can be provided,
The method for exposing the inner lead portion 3b does not matter at all. Of course, since the resin package 2 is for protecting the chip or the wire bonding portion inside the resin package 2, as long as such a protection function is achieved, the inner lead portions 3 are different from those of the conventional package form.
The part of the package 2 may be removed so that the upper surface of b is exposed.

Then, such a thing can be easily carried out only by changing the cavity shape of the upper mold used in the resin molding process.

The surface mount type resin package type electronic component as shown in FIG. 1 or FIGS. 4 and 5 is mounted on the circuit board 4 by so-called solder reflow. A wiring pattern 8 is previously formed on the substrate 4 so as to form a predetermined hybrid circuit by combining a plurality of electronic components. Then, cream solder is applied by printing onto a predetermined portion of the wiring pattern, and the electronic components 1 are mounted on the board 4 in such a manner that the leads 3 are mounted on the cream solder. 4 is introduced into the heating furnace. Then, the solder component in the cream solder is melted and then solidified, and the lead 3 a and the wiring pattern 8 corresponding thereto are joined by the solder 10.

When the electronic component 1 is mounted on the substrate 4, it is preformed so that all the leads 3 come into contact with the wiring pattern to be connected, but the leads 3 due to a forming error or an external force.
Due to the deformation, some of the leads 3 may float up as shown by the phantom line in FIG. Then, even after the above-described solder reflow process, the soldering between the lead 3 and the wiring pattern 8 cannot be properly performed. Such a solder connection failure is difficult to visually detect when the number of electronic components mounted on the substrate is large, and the number of leads extending from one electronic component is large, and it is also difficult to detect it visually. However, even if it is detected, it requires an extremely expensive device and complicated operation.

In order to detect such a connection failure (open failure), the simplest and surest method is to pass an electric current between two points sandwiching this connection part, and the present invention is such a simple and reliable method. I was able to actually do.

For example, to detect an open defect between the lead 3 and the wiring pattern 8 on the substrate shown in FIG.
The inner lead portion 3b exposing the upper portion of the lead 3
And the wiring pattern 8 to which the lead is to be soldered
It suffices to bring the measurement probes 11 and 11 into contact with and check whether or not a current flows between them. In the electronic component 1 of the present invention, the inner lead portion 3b is a resin package 2
Since it is exposed from the side edge of the inner side of the inner lead portion 3b, even if the measuring probe 11 is applied to the inner lead portion 3b from above, it does not apply an external force to the entire lead 3.

That is, assuming that the measurement probe 11 is brought into contact with the lead 3 which is lifted as described above, the lifted lead is pressed against the wiring pattern of the substrate 4 due to the pressing force of the probe 11, and at this point an open defect occurs. Will be healed,
After all, the open failure cannot be detected, but according to the present invention, even if the measurement probe 11 is brought into contact with the inner lead portion 3b as described above, the external force does not act on the floating lead, so that the open lead can be reliably performed. It becomes possible to detect the open defect of the lead.

Further, by the above-mentioned method, the simplification is remarkably simplified as compared with the open / short inspection method which has been inevitably adopted. As described above, in the past, as it was not possible to apply the measurement probe to the lead itself as described above, the wiring pattern on the circuit board was selected based on the circuit analysis of electronic parts, and the parasitic of internal elements was selected. In order to confirm whether or not the diode is functioning, the method of contacting the measurement probe between two points on the wiring pattern to which the two selected leads are to be connected has been unavoidable. Compared with such a conventional method, the present invention does not require a complicated circuit analysis and is simply provided between the inner lead portion 3b of the lead to be inspected and the wiring pattern 8 to which the lead to be inspected is to be soldered. If the measuring probes 11 and 11 are brought into contact with each other, it is possible to reliably inspect all the leads.

Further, for example, as shown in FIG. 3, the lead 3 of one electronic component and the lead of another electronic component to be electrically connected to this via the wiring pattern 8 are provided without using the wiring pattern. A simple open inspection can also be performed by bringing the measurement probes 11 and 11 into contact with the inner lead portions 3b and 3b. According to this method, conventionally, it was necessary to select all wiring patterns on the circuit board and provide measurement points therefor. Compared with the conventional method, unnecessary parts of the circuit board were saved and the entire circuit board was downsized. It is also possible to plan.

Of course, the scope of the present invention is not limited to the above embodiments. The shape of the deletion portion to be provided in the resin package in order to expose the inner lead portion of each lead upward can be variously changed other than the illustrated example.

The above embodiment is an example in which the lead 3 is bent in a crank shape and the horizontal bent portion 3a which should come into contact with the substrate is extended outward. As shown, the present invention can also be applied to a case where a horizontal portion that should come into contact with the substrate wraps around the back side of the resin package 2 and is bent inward. Conventionally, in such an electronic component in which the lead is bent inward, since most of the soldered portion is wrapped around the back surface of the resin package 2, it is difficult to perform visual inspection, but according to the present invention, In this respect, it is very effective. In this case, on the back surface of the resin package 2, as shown in FIG.
And the rail or girder portion 2 as shown in FIG.
Even if a is provided and the measurement probe 11 is pressed against the inner inner lead portion 3b of the lead 3, the force is received by the substrate 4 by the rail or the girder portion 2a, and the lead 3 is caused by the pressure of the measurement probe 11. It is necessary to keep the external force from

[Brief description of drawings]

FIG. 1 is an overall perspective view of an embodiment of an electronic component of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an explanatory diagram of an example of an inspection method of the present invention.

FIG. 4 is an overall perspective view of another embodiment of the electronic component of the present invention.

FIG. 5 is an overall perspective view of still another embodiment of the electronic component of the present invention.

6 is a sectional view taken along line VI-VI in FIGS. 4 and 5. FIG.

FIG. 7 is a partial side view of still another embodiment of the electronic component of the present invention.

FIG. 8 is a view on arrow VIII in FIG.

FIG. 9 is an overall perspective view of a conventional example.

FIG. 10 is a cross-sectional view for explaining the problem of the conventional example.

[Explanation of symbols]

 1 Electronic Component 2 Resin Package 3 Lead 3b Inner Lead Part 4 Board 8 Wiring Pattern 11 Measurement Probe

Claims (2)

[Claims] 1. An electronic component comprising a lead extending from a side surface of a resin package, wherein a part of an upper surface of an inner lead portion of the lead is exposed inside a side edge of the resin package. The characteristic electronic component. 2. The device according to claim 1, which is mounted by soldering.
A method of inspecting a circuit board including an electronic component, comprising: the exposed inner lead portion of the electronic component;
A method of inspecting a circuit board, which comprises inspecting the wiring pattern on the circuit board or the exposed inner lead portion of another electronic component by contacting the measuring probe.