JPH06334064A - Leadless surface mounting hybrid ic - Google Patents

Abstract

PURPOSE:To provide a leadless surface mounting hybrid IC in which the characteristics can be tested highly accurately prior to mounting and the mounting operation onto the surface of a mother board can be improved significantly. CONSTITUTION:In the leadless surface mounting hybrid IC in which a connection terminal 7 coated with a solder layer 8 is led out at least to the rear side, the solder coat layer 8 is planarized. In such structure, the solder coat layer 8 on the surface of the connection terminal 7 is exposed to the surface of a resist layer formed substantially in flush therewith or projecting slightly therefrom so that the solder coat layer 8 can be formed thick.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leadless surface mount hybrid IC and a method of manufacturing the same, and more particularly to a leadless surface mount hybrid IC improved for mounting on a motherboard.

[0002]

2. Description of the Related Art In order to achieve higher density and higher functionality of electronic equipment, there is a mounting circuit device in which mounting components such as chip type and flat package type are mounted and mounted on the main surface of a so-called wiring board. Widely used for practical use. Also,
In the construction of a mounting circuit device of this type, a so-called hybrid IC in which predetermined electronic components are mounted on a wiring board surface to form a certain circuit in consideration of higher functionality and mass productivity, is used as a mother board. A configuration is also adopted in which the main wiring board is placed and mounted in a predetermined area. Further, in the multi-stage mounting configuration in which the hybrid IC is mounted on the motherboard, the efficient utilization of the motherboard surface,
In terms of mounting operability and the like, as a hybrid IC to be mounted, a leadless surface mounting type hybrid IC having a configuration shown in a sectional view in FIG. 3 has attracted attention and is often used.

In FIG. 3, reference numeral 1 is a wiring board such as a thick film wiring board, and 2 is a metal cap, for example, and required electronic components mounted on one main surface of the wiring board 1, for example, a semiconductor element. , Protects low antibodies, capacitors, etc., or acts as an electromagnetic shield. 3 is a connection terminal (electrode pad) formed of a thick film pattern led out to the back surface side of the wiring board 1, and 4 is a solder coat which is coated / disposed on the connection terminal (electrode pad) surface by, for example, printing or reflowing. It is a layer.

[0004]

However, in the case of the leadless surface mount type hybrid IC having the above configuration,
In practice, the following inconvenient problems often occur. That is, at the stage of mounting the leadless surface-mounting hybrid IC on a predetermined area surface of a mounting main wiring board (motherboard), the solder coat layer 4 on the surface of the connecting terminal 3 is mounted.
However, since it is not a uniform thickness (height) as a whole and has a projection shape, it is difficult to maintain a reliable contact state with the connected terminal (electrode) surface of the motherboard. Positional deviation and the like are likely to occur, so that it often happens that reliable soldering and joining cannot be achieved. More specifically, the solder coat layer 4 on the surface of the connection terminal 3 is generally formed by printing eutectic cream solder and solder-coating it by reflowing. The solder thus formed has a hemispherical shape having bulges due to surface tension. And the hemispherical shape having this bulge not only causes the occurrence of height variations, but also
Since the contact surface (apex) is also reduced, there is a possibility that it will hinder reliable soldering.

On the other hand, this type of leadless surface mounting type hybrid IC is subjected to individual (or extraction) characteristic inspection prior to mounting on a mother board, but the solder coat layer 4 on the surface of the connection terminal 3 is used. Due to variations in thickness (height), protrusions, and the like, poor connection with the connection terminals of the measurement jig (inspection device) is likely to occur, which complicates the characteristic inspection operation.

The present invention has been made in consideration of such circumstances, and a leadless surface which can perform characteristic inspection prior to mounting with high accuracy and can greatly improve mounting operation on a motherboard surface. The purpose is to provide a mounted hybrid IC.

[0007]

The leadless surface-mounting hybrid IC of the present invention is a leadless surface-mounting hybrid IC in which at least a connection terminal solder-coated on the back surface side is led out, and the leadless surface-mounting hybrid IC is formed on the back surface side. It is characterized in that the lead-out solder coating layer on the connection terminal surface is flattened. Further, in this configuration, if necessary, a resist layer that is flush with or lower than the surface of the solder coat layer on the surface of the connection terminal is disposed on the periphery of the solder coat layer.

In the present invention, the solder layer on the connection terminal surface is a solder used for electrical connection in this type of electronic component, such as various eutectic solders such as 63% Sn-37% Pb. In addition, it is also possible to form using solder having a solidus temperature and a liquidus temperature. When the eutectic solder is used, the features such as simple melting and solidification process and good fluidity are utilized, and when it is formed with the solder having the solidus temperature and the liquidus temperature, it is softened. Depending on the state or the gradual melting property, it is easier to perform the flattening process with a uniform thickness.

The flattening of the solder coat layer formed on the connecting terminal surface is performed, for example, by once melting and curing the printed / adhered solder, and then again from the solidus temperature to the liquidus temperature. A film (layer) is obtained by heating and softening, or by re-curing under a pressure between flat plate (surface) jigs at a temperature between the solidus temperature and the liquidus temperature, under pressure. The thickness can also be achieved in a uniform manner. Then, in flattening the solder coat layer, by providing a resist layer having a thickness that allows the solder coat layer to be formed on the adjacent peripheral surface except the connection terminal surface, relatively. It is possible to form and provide a flat and uniform solder coat layer having a uniform thickness, and it is possible to substantially eliminate or suppress solder outflow during soldering or mounting on the motherboard surface. In addition,
Here, the thickness of the solder coat layer can be made slightly higher than that of the resist layer provided in the peripheral portion (a shape protruding from the resist layer surface), and in this case, it can be easily mounted on an inspection jig or the like.

[0010]

In the structure of the leadless surface mounting type hybrid IC described above, at least the solder coat layer on the connection terminal surface led out to the back surface is flattened and the thickness thereof is substantially uniform. When surface mounting to
Since the surfaces to be connected to each other can be brought into contact with each other with high accuracy and reliability, highly reliable mounting is achieved. Further, even in the characteristic inspection of each of the leadless surface mounting type hybrid ICs, highly reliable and reliable contact with the connection terminal of the inspection jig is possible, so that the characteristic inspection with high reliability can be easily performed. .

[0011]

Embodiments of the present invention will be described below with reference to FIGS.

Embodiment 1 FIG. 1 shows a leadless surface mount type hybrid I according to the present invention.
It is a cross-sectional view showing the main part of one structural example of C. Figure 1
5 is a wiring board such as a thick film wiring board, 6
Is a required electronic component mounted on one main surface of the wiring board 5,
For example, semiconductor devices, low antibodies, capacitors, etc.
Further, 7 is a connecting terminal (electrode pad) composed of a thick film pattern led out to the back surface side of the wiring board 5, and 8 is 63% Sn-37% on the surface of the connecting terminal (electrode pad).
Printing and reflow coating of Pb solder (eutectic solder) cream
It is the arranged solder coat layer having a flat surface.

The leadless surface-mounting hybrid IC according to the present invention having the above-described structure has a conventional structure except that the solder coat layer 8 formed on the surface of the connecting terminal 7 is flattened. Since it is basically the same as the above, the manufacturing or assembling can be performed by a conventional means except that the flattening treatment (process) of the solder coat layer 8 is intentionally performed. That is, it is adhered and overlaid on the surface of the connecting terminal 7 composed of the thick film pattern led out to the back surface side of the wiring board 5 constituting the leadless surface mounting type hybrid IC by, for example, a printing method, a dipping method or a plating method. The leadless surface-mount hybrid IC is a means for re-hardening the solder once it has been melted and hardened, then heated again to the solidus temperature to soften it, and then pressed with a flat plate-shaped jig. In addition to the conventional manufacturing (assembling) means, a leadless surface-mounting hybrid IC having a solder coat layer 8 having a uniform film (layer) thickness and a flat surface on the connection terminal 7 surface is provided. can get.

More specifically, a pitch interval of 2.54 mm led out to the back surface side of the thick film printed wiring board 5 made of ceramics.
The eutectic solder layer is printed / deposited on each connecting terminal 7 surface of the connecting terminal 7 group having a diameter of about 1.0 mm through a metal mask, and then the solder layer is reflowed and cured to be shaped. After that, while being heated to the eutectic temperature again, the solder layer on the surface of each of the connecting terminals 7 is pressed almost uniformly by the flat ceramic plate, and all the solder layers are almost even. A leadless surface-mounting hybrid IC having a uniform thickness and a flat surface was finally obtained.

Further, in the above, the area surface other than the area of the connecting terminal 7 led out to the back surface side of the thick film printed wiring board 5 is adhered on the surface of the connecting terminal 7 by, for example, photoresist patterning. A leadless surface-mount hybrid IC was constructed according to the above configuration and manufacturing method except that the resist layer 9 having a thickness corresponding to the thickness of the solder coat layer 8 to be formed was selectively provided. FIG. 2 is a cross-sectional view showing the structure of a main part of this leadless surface-mount type hybrid IC. The back surface side of the thick film printed wiring board 5 includes 10 parts of other wiring except for the connection terminal 7 region. The entire surface is covered with the resist layer 9, and the solder coat layer 8 is embedded in the surface of the connecting terminal 7 so as to be substantially flush with the resist layer 9. Further, in this configuration, it is possible to form the solder coat layer 8 which is accurately positioned and easily flattened by the previously patterned resist layer 9. That is, even when the connection terminals 7 are relatively minute and arranged at a narrow pitch, the side wall surface of the resist layer 9 functions as a weir, and the connection terminal 7 portion is divided and exposed. The solder coat layer 8 having a required surface flattened with high accuracy and reliability can be provided, and highly reliable electrical connection / mounting can be achieved.

When these leadless surface-mounting hybrid ICs were mounted on a predetermined inspection jig and a characteristic inspection was performed, it was possible to easily set the corresponding connecting portions of the two without causing misalignment. In addition, the electrical connection can be surely ensured, and the characteristic inspection can be performed without any complexity. In particular, in the above case, when the solder coat layer 8 is configured to slightly project from the surface of the resist layer 9, it is easy to mount and contact with the inspection jig, so that the characteristic inspection can be performed more easily.

Further, when the leadless surface-mounting hybrid IC is mounted on a required mother board surface to form a mounting circuit device, the corresponding connecting portions of the both are easily set without causing a positional deviation or the like. In addition to being able to ensure the electrical connection, it functioned as a highly reliable mounted circuit device.

Embodiment 2 In the case of Embodiment 1, each connection terminal of the connection terminal 7 group having a pitch interval of about 2.54 mm and a diameter of about 1.0 mm led out to the back side of the thick film printed wiring board 5 made of ceramics. 7
Surface, through a metal mask, for example, 45% Sn-55% Pb
After printing and depositing a solder layer having a solidus temperature and a liquidus temperature, such as solder or 46% Sn-8% Bi-46% Pb solder, approximately 200 ° C or 165 ° C (both solid phase When the solder layer of the connecting terminals 7 group is pressed almost uniformly by a flat ceramic plate in a state of being heated to a temperature between the line temperature and the liquidus temperature and softened, all solder is Finally, a leadless surface-mount type hybrid IC in which the layers had a substantially uniform thickness and were flattened was obtained. Here, when the solder layer printed / deposited on each connection terminal 7 surface is flattened, the solder exhibits an appropriate softened state, so that a short circuit due to the outflow of solder from the adjacent connection terminal 7 surface, or Good workability and yield were exhibited without causing appearance defects.

Further, as in the case of the first embodiment, the characteristic inspection by mounting on a predetermined inspection jig and the performance evaluation of the mounted circuit device mounted on the mother board surface were carried out. It was confirmed that a reliable characteristic test can be achieved and that a reliable function is exhibited.

Further, as the solder having the solidus temperature and the liquidus temperature, for example, 90% Sn-10% Pb solder, 80
% Sn-20% Pb solder, 70% Sn-30% Pb solder, 55% Sn-45%
Pb solder, 50% Sn-50% Pb solder, 40% Sn-60% Pb solder, 35
% Sn-65% Pb solder, 30% Sn-70% Pb solder, 25% Sn-75%
Similar results were observed using Pb solder.

Further, in the case of the first embodiment, instead of using the eutectic solder as the solder for forming the solder coat layer 8, solder having a solidus temperature and a liquidus temperature is used. Of a leadless surface-mounting hybrid IC having the same configuration as that shown in FIG. 1 and is mounted on a predetermined inspection jig to perform characteristic inspection, and performance evaluation of a mounted circuit device formed by mounting on a motherboard surface. As a result, it was confirmed that a highly reliable characteristic test could be achieved and that a highly reliable function was exhibited.

In the above description, the connection terminal 7 is led out only on the back surface side of the wiring board 5. However, for example, when the leadless surface mounting type hybrid IC is mounted in a multi-layered (multi-stage) manner, etc. Similarly, the solder coat layer may be flattened on the connection terminal surface led out to the mounted electronic component group 6 side.

[0023]

As described above, in the leadless surface mounting type hybrid IC of the present invention, at least the solder coat layer on the connection terminal surface led out to the back surface is flattened and the thickness thereof is also substantially uniform. Therefore, when surface-mounting on the motherboard surface, the connecting parts that connect to each other can be accurately
In addition, since it is possible to reliably contact each other, highly reliable mounting can be achieved. Further, in the characteristic inspection of each leadless surface-mounting hybrid IC, the connection terminal portions can be surely brought into contact with each other, so that the characteristic inspection with high reliability can be easily performed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a configuration example of a leadless surface-mounting hybrid IC according to the present invention.

FIG. 2 is a sectional view showing a main part of another configuration example of the leadless surface-mounting hybrid IC according to the present invention.

FIG. 3 is a cross-sectional view showing a main part of a conventional leadless surface mount hybrid IC.

[Explanation of symbols]

1, 5 ... Wiring board 2, 6 ... Mounted electronic component group 3, 7
... Connection terminals 4, 8 ... Solder coat layer 9 ... Resist layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Sakamoto 4-3-1, Higashishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Lighting & Technology Corporation

Claims (4)

[Claims] 1. A leadless surface-mounting hybrid IC in which at least a connection terminal solder-coated on the back surface side is led out, and a solder coat layer on the connection terminal surface led out on the back surface side is flattened. Leadless surface mount hybrid IC. 2. In a leadless surface-mounting hybrid IC in which at least a back surface side of a connection terminal solder-coated is led out, a solder coat layer of the connection terminal surface led out to the back surface side has a solidus temperature. And formed of solder having a liquidus temperature,
A leadless surface-mounting hybrid IC characterized by being flattened. 3. A leadless surface mounting type hybrid IC in which at least a connection terminal solder-coated on the back surface side is led out, and a resist layer is provided in the peripheral portion of the connection terminal surface led out on the back surface side. A leadless surface-mount type hybrid IC, wherein the solder coat layer on the connection terminal surface is flattened to match the resist layer. 4. The leadless surface-mounting hybrid IC according to claim 3, wherein the flattened solder coat layer of the connection terminal surface projects from the adjacent resist layer surface.