JPH07162106A - Wiring board - Google Patents

Abstract

PURPOSE:To heat a specified solder part, with no external heating device, for mounting/dismounting a part by providing an electrical connection part on the surface and, near the electrical connection part, a heat generating body and a power feeding wire connected to it as well. CONSTITUTION:A heat generating areas 41 and 42, wherein LSI connection bumps 210 and 220 and power feeding points 300, 310 and 320 on the first layer and a heat generating body on the second layer are provided, and power feeding wire 529 for them are provided. In addition, wiring patterns 520, 521 and 522 which are power-fed by the first layer, a via hole 931 of a logic LSI, a wiring 953 on the third layer, via holes 941 and 942 which connect the third of the fourth and fifth layers, and a wiring 594 on the fourth layer, are provided. To heat a metalized part at a solder-connection point, a heat generating body and a power feeding part for it are provided on a substrate, and by heating only a specified solder part, module-assembly is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board for attaching and detaching components by utilizing a heating element provided on the board.

[0002]

2. Description of the Related Art There is a strong market need for high performance and miniaturization of electronic equipment, and research and development of high integration and miniaturization of components and high density packaging of these components have been continued. Further, in recent years, environmental measures, energy saving, and consideration of recyclability have been required for products and their manufacturing processes. In the manufacturing process of electronic devices, there is a heating process like the soldering process, and energy saving at this stage is desired. Further, in order to improve recyclability, it is desired to develop an efficient disassembling method and separating method for the components mounted on the board.

In the technique of connecting components to a wiring board according to the prior art, from the viewpoint of the order of supplying components and solder to the substrate, the solder is supplied first, which is the reverse of the method in which the components are supplied before the solder is supplied. It is roughly divided into methods (reflow method). Both require a step of melting the solder. In the method of supplying components first, the immersion method of immersing the substrate in a molten solder bath after mounting the components is used in mass production, but the melting of this solder depends on the heating of the bath. 61-273256). The heating method by the reflow method is divided into a method of heating the whole substrate and a method of heating a part of the substrate. As the heating means, a hot plate, a hot-air stove, an infrared furnace, and heating steam are filled as the whole heating. For local heating of the bath, a method utilizing a trowel, a laser beam, a high frequency, and an electric current has been developed. Even when parts are removed for repairs, the solder at the connection point is melted by the above heating method (Osawa Nao, "Soldering Technology for Electronic Materials" Industrial Research Committee, 1983, page 149-
170).

[0004]

In the method of immersing and connecting a board in a solder bath and the method of connecting the whole board by heating with a hot plate, a furnace, etc., when the board is enlarged, The hot plate and furnace must be enlarged. In these methods, the energy input cannot be improved because the energy input is consumed not only for melting the solder but also for increasing the temperature of the inner wall of the tank, hot plate, furnace, etc. Further, when the components are removed from the mounting board, the solder connection points of all the components are heated, so that it is not possible to remove only the specific components, which is unsuitable for repair, separate collection of the components, and the like.

In the method of locally heating the solder portion,
It took a long time to align the heating device with the corresponding solder portion, and required a device for alignment. Also, when attempting to mount components at high density, it may not be possible to align the heating device with the solder part depending on the spatial arrangement of the components, which is not suitable for mass production of high-density mounted electronic circuits. It was

An object of the present invention is to provide a wiring board capable of heating a specific solder portion and attaching / detaching a component without using an external heating device.

[0007]

In order to solve the above-mentioned problems, the present invention has an electric connection part on the surface, a heating element near the electric connection part, and a power supply for connecting to the heating element. Provided is a wiring board provided with wiring.

There is provided the above-mentioned wiring board in which the electrically connected portions are divided into one or a plurality of groups, and each of the groups is provided with a dedicated heating element and a power supply wiring connected thereto.

There is provided the above wiring board in which a heating element is provided in a layer different from a layer having an electrical connection portion.

The above wiring board having therein a wiring electrically connected to an electrical connection portion, a heating element electrically insulated from the wiring, and a layer provided with a wiring electrically connected to the heating element provide.

There is provided the above wiring board using a resistance heating element as a heating element and glass, ceramics or an organic polymer as a base material of the substrate.

There is provided the above wiring board in which a heating element is formed of a metal or semiconductor plate, a sintered body, a plating product, or a vapor deposition material.

There is provided the above wiring board in which an electrical connection portion is formed of a metal or semiconductor plate, a sintered body, a plating product, or a vapor deposition material.

There is provided the above wiring board in which a metal or an alloy is melted or solidified in an electrical connection portion.

A component attaching / detaching method of connecting or detaching a component to / from the wiring substrate by melting and solidifying a metal or an alloy in an electrically connecting portion by a heating element provided on the wiring substrate is provided. provide.

[0016]

When the component is connected to the wiring board according to the present invention, the heating element provided on the wiring board is heated by externally feeding power to the feeding point so that the temperature of the predetermined metallized portion is equal to or higher than the melting point of the solder. To melt the solder and wet the component and the metallized portion with the molten solder, and then lower the power supply to reduce the amount of heat generation to solidify the solder and connect the component and the metallized portion.

When a component soldered to the wiring board according to the present invention is removed, the heating element provided on the wiring board is heated by externally feeding power to the feeding point.
The temperature of the prescribed metallized portion is raised to above the melting point of the solder to melt the solder, the above component is externally removed from the metallized portion, and if necessary, the solder remaining on the substrate metallized portion is removed, and then the removed component In order to prevent re-connection of the metallized part and to prevent the temperature of other metallized parts from becoming higher than the melting temperature of the solder, the power supply is lowered to reduce the heat generation amount.

[0018]

EXAMPLE 1 An example in which the present invention is applied to a substrate for a ceramic thick film module for an electronic computer is shown in FIG. FIG. 1A shows a perspective view of the LSI mounting surface of the multilayer wiring board 100. Multilayer wiring board 1
00 is a connection bump 210 for the logic LSI 610,
Connection bumps 220 for the memory LSI 620, the logic, and feeding points 300, 310, 32 to the heating elements 410, 420 provided on the multilayer wiring board 100 for connecting the memory LSI.
0 is provided. The bumps 210 and 220 are metallized so that the molten solder can be wet and connected. The power feeding points 300, 310 and 320 are also metalized so that they can be energized from the outside.

FIG. 1B shows the back surface of the above-mentioned multilayer wiring board 100, which is not shown in FIG. A. Connecting pins 250 of pins 750 for sending signals and power supplies from the outside to the above module, and feeding points 3 to the heating element 450 for heating the bumps 250
There are 50 and 351. The connection bumps 250 and the feeding points 350 and 351 are also metalized.

FIG. 1C shows a cross section of the multilayer wiring board 100 at aa '. The multilayer wiring board 100 has 10 layers. The layer structure is as follows: a first layer provided with bumps for LSI connection, a second layer below which is provided a heating element for heating the bumps for LSI connection, and third to eighth layers for wiring. ,
The ninth layer is provided with a heating element 450 of a bump for pin connection, and the tenth layer is provided with a bump for pin connection. Conduction between layers was performed by via-hole wiring filled with metal.

FIG. 2 shows the bumps 21 for LSI connection of the first layer.
0, 220, power feeding points 300, 310, 320 and heat generating areas 41, 42 provided with second layer heating elements, power feeding wirings 529 to them, and wiring patterns 520, 521 receiving power feeding from the first layer. 522, the logic L of the third layer
The positional relationship between the SI via hole 931, the memory LSI via hole 932, the wiring 593 in the third layer, the via holes 941 and 942 connecting the third and fifth layers of the fourth layer, and the wiring 594 in the fourth layer is shown. Show.

FIG. 3 shows the details of a part of the heat generating area 42 and the positional relationship between the patterns of the first layer, the second layer and the third layer. The second layer via hole wiring 922 was provided at a position where the via hole wiring 912 provided for electrically connecting the first layer connection bump 220 to the second layer could be connected. Further, the via hole wiring 922 is connected to the via hole wiring 932 in the third layer. The heating element 420 is formed so as not to be electrically connected to the via hole 922, and is connected to the power supply wiring 529.

FIG. 4 shows a method for forming the above-mentioned second layer. A sheet 2 was formed by tape-casting a mixture of ceramic powder and a binder and forming a slurry. A through hole 92 was punched at a predetermined position on the sheet 2. The through hole 92 was filled with a conductor metal paste by a screen printing method to form a via hole wiring 922. Next, a wiring 529 for energizing the heating element 420 was formed by screen printing. From above, a metal paste for a heating element is used as a heating element 420 also formed by the screen printing method. These printed materials are integrated and conductive after all layers are laminated and sintered.

FIG. 5 shows an assembling method. Connection bump 21
Flux was applied to No. 0 to print the cream solder 20 on the connection bumps 220. The logic LSI having the CCB 22 formed by solder sputtering on the back surface is placed on the connection bumps 210, and the feeding points 300 and 310 are energized to heat the heating element 410 in the heating area 41 provided in the lower layer of the connection bumps 210. , CCB22 is melted, then the current is stopped and the CCB22 is solidified.
610 was connected to the wiring board 100. About 5 for this connection
It takes a minute, and the energizing power is about 400W, C
It was about 1 W per CB. Subsequently, the memory LSI is placed on the connection bumps 220, and the feeding points 300, 32
0 to turn on the cream solder 2 on the connection bump 220
0 was melted, electricity was stopped to solidify the solder, and the memory LSI 620 was connected to the wiring board 100. About 400 W of electric power was required for 5 minutes to connect this memory LSI.

After connecting the above LSI, the pin 750 is
The solder preform 21 is placed on the connection bumps 250 of the pins, and the pins 750 are pressed against the bumps 250 to feed the power supply points 35.
0, 351 is energized to heat the pin connecting heating element 450 provided in the ninth layer to melt the solder preform 21, then the energization is stopped, and the solder preform is solidified and waits for connection. I removed the pin retainer. During this time,
The LSI mounting surface side was air-cooled with a weak wind. This pin connection consumed an average of 900 W of power for about 10 minutes. Therefore, about 870 kJ of energy was consumed in this series of connections. Further, as the solders 20, 21, and 22 described above, those having a melting point of 180 to 200 degrees were used.

Conventionally, in the above module assembly, solder having a melting point of 270 degrees is used for LSI connection, and heating is performed for about 10 minutes in a reflow furnace having an average power consumption of 4 kW to melt and cool the solder. Next, the solder having a melting point of 200 degrees was heated again for about 10 minutes in the reflow furnace having the average power consumption of 4 kW for the pin connection. Therefore, about 4800 kJ was consumed. Therefore,
According to the present invention, the power consumption can be reduced to one fifth or less in assembling the module. Moreover, the width of the temperature hierarchy of the solder could be narrowed.

Embodiment 2 FIG. 6 shows a second embodiment of the present invention. Printed board 801
Is a layer 811 having a heating element metal formed under the component mounting layer.
Is a multi-layer printed board. The heating element 814 is the condenser 804, the heating element 812 is the IC 802, and the heating element 813.
Are arranged near the connection point of the resistor 803. A thin side of tungsten was used for the heating element, and thermocompression bonding was performed so as to be in contact with the wiring for feeding the heating element of the layer 811. Since an abnormality was found in the assembled substrate 801, it was considered that the capacitor 804 was deteriorated when inspected. Therefore, power was supplied to the capacitor heating element 814 to generate heat to melt the solder in each capacitor part, and Only the capacitor 804 was collected by suction from the mounting surface, the metal sponge was pressed against the connecting point trace of the capacitor 804 to absorb and remove the solder residue, and then the power supply to the heating element 814 was stopped and air cooling was performed. Cream solder is newly applied to the connection point of the capacitor 804, a new capacitor is placed, the heating element 814 is energized to heat the connection point of the capacitor 804, and the cream solder applied to the connection point is melted. After stopping, the power supply was stopped. The confirmation of the melting of the solder was based on visually observing the change in the gloss of the solder. At a later date, the board has been used up, so for capacitors, resistors, I
The heating elements 814, 813, and 812 for C were sequentially energized and heated to melt the solder, and then sucked to collect each of the capacitors, resistors, and IC component types, and separately discard them.

[0028]

According to the present invention, in order to heat the metallization of the solder connection point, the substrate is provided with a heating element and a power feeding portion to this heating element, and only a predetermined solder portion is heated, so that the reflow furnace is used. It was possible to assemble the module by connecting the components and pins to the wiring board with about one-fifth of the amount of electricity as compared with the case where it was used.

Further, according to another embodiment of the present invention, a specific component mounted on a printed board is melted with solder of the component without externally aligning a heating tool to the position, It was possible to replace, and furthermore, it was possible to collect each component type without using a special jig or a component discriminating device.

[Brief description of drawings]

FIG. 1 is a perspective view and a cross-sectional view of the front and back surfaces of an embodiment of the present invention.

FIG. 2 shows a heating area and connection bumps according to one embodiment of the present invention,
It is a wiring pattern diagram of each layer from the first layer to the fourth layer for showing the positional relationship with the internal wiring.

FIG. 3 is a wiring pattern diagram showing a positional relationship between a heating element in a heating area and a connection bump to be heated and an arrangement of a heating element, a power supply wiring and a via hole wiring for an interlayer wiring according to an embodiment of the present invention. It is sectional drawing which shows the relationship between details and an upper and lower layer.

FIG. 4 is a diagram showing a procedure for forming a heating element, power supply wiring, and via hole wiring according to an embodiment of the present invention.

FIG. 5 is a front and back perspective view showing an assembly procedure of an embodiment of the present invention.

FIG. 6 is a perspective view of another embodiment of the present invention, and is a view for showing the position of the heating element provided on the inner layer of the heating element.

[Explanation of symbols]

1 ... 1st layer, 2 ... 2nd layer, 3 ... 3rd layer, 4 ... 4th layer, 9
... 9th layer, 10 ... 10th layer, 20 ... Cream solder, 2
1 ... Solder preform, 22 ... Solder CCB 41 ... Heating area, 42 ... Heating area, 92 ... Through hole,
100 ... Multilayer wiring board, 210 ... Connection bump, 220 ... Connection bump, 250 ... Connection bump, 300 ... Feed point, 31
0 ... Feeding point, 320 ... Feeding point, 350 ... Feeding point, 351
… Feeding point, 410… Heating element, 420… Heating element, 520…
Wiring pattern, 521 ... Wiring pattern, 522 ... Wiring pattern, 529 ... Power feeding wiring, 593 ... Wiring, 594 ...
Wiring, 610 ... Logic LSI, 620 ... Memory LS
I, 750 ... Pin, 801 ... Printed board, 802 ... I
C, 803 ... Resistor, 804 ... Capacitor, 811 ... Internal heating layer, 812 ... IC heating element metal, 813 ... Resistance heating element metal, 814 ... Capacitor heating element metal, 912
... Via hole wiring, 922 ... Via hole wiring, 931 ...
Via hole wiring, 932 ... Via hole wiring, 941 ... Via hole wiring, 942 ... Via hole wiring.

Front Page Continuation (72) Inventor Naoki Matsushima 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock Engineering Research Institute, Hitachi, Ltd.

Claims (9)

[Claims] 1. A wiring board having an electric connection portion on a surface thereof, wherein a heating element and a power supply wiring connected to the heating element are provided in the vicinity of the electrical connection portion. 2. The wiring according to claim 1, wherein the electrically connected portion is divided into one or a plurality of groups, and each of the groups is provided with a dedicated heating element and a power feeding wiring connected to the heating element. substrate. 3. The wiring board according to claim 1, wherein the heating element is provided in a layer different from a layer having an electrical connection portion. 4. A wiring internally connected to an electrical connection portion, a heating element electrically insulated from the wiring, and a layer provided with a wiring electrically connected to the heating element are provided inside. The wiring board according to claim 1, which is characterized in that. 5. The wiring board according to claim 1, wherein a resistance heating element is used as the heating element, and glass, ceramics or organic polymer is used as the base material of the substrate. 6. The wiring board according to claim 1, wherein the heating element is formed of a metal or semiconductor plate, a sintered body, a plating product, or a vapor deposition material. 7. The wiring board according to claim 1, wherein the electrical connection portion is formed of a metal or semiconductor plate, a sintered body, a plating product, or a vapor deposition material. 8. The wiring board according to claim 1, wherein the metal or alloy is melted or solidified by the heat from the heating element in the electrically connected portion. 9. A heating element provided on a wiring board melts and solidifies a metal or an alloy in an electrically connecting portion to connect or disconnect the parts from the wiring board. A characteristic part attachment / detachment method.