JPH01191491A - Multiple circuit board - Google Patents

Abstract

PURPOSE:To make it possible to perform high density mounting at a low cast at high reliability, by fixing and connecting the electrodes of chip type electronic components to printed electrodes dedicated for soldering in an insulating rectangular parallelopiped body, and overlapping a plurality of circuit boards through said chip type electronic components so as to form a unitary body. CONSTITUTION:Conductor chips 3 are to be provided between a first mounting board 1 and a second mounting board 2. The conductor chips 3 are mounted on the first mounting board 1 together with other surface mounting components, i.e., so-called chip type electronic components 8, so that conductors 4 agree with solders 5. Solders 7 are printed on conductive surface 6 of the other prepared second mounting board 2. The upper surfaces of the conductor chips 3 are brought into contact with the solders 9. A mounting gap J between the first mounting board 1 and the second mounting board 2 is determined by a height H of the conductor chip 3. Tin-lead (weight ratio of 63-37) can be used for the solder. The low temperature solder containing bismuth or the solder containing silver can be also used. A heater source for heating upper and lower parts at the same time is desirable. As the kinds of the heat sources, any of infrared rays, direct infrared rays and electric heating can be used. A conveying device wherein the following conditions can be controlled is desirable: e.g., 215 deg.C+ or -5 deg.C and 15 seconds + or -1 second.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a circuit board used in electronic equipment, and more particularly to a stacked structure of a plurality of circuit boards.

Conventional technology Conventionally, multilayer wiring boards with through-hole plating connections are made of glass cloth-based epoxy resin laminated materials when components are arranged only on the upper and lower surface layers. It was manufactured using. Additionally, some ceramic multilayer wiring boards are also manufactured with through-hole connections.

Next, as a second method, when a component is present in a gap between circuit boards, it is easy to imagine a structure in which through holes are formed at the four corners of the circuit board and four pillars are passed through. In addition, as a third method, a large number of half-moon-shaped notches called notches are provided at the end of the ceramic substrate, the walls of which are metalized, and lead wires etc. are soldered and connected to each other at certain intervals. There is a structure that consists of arranged circuit boards, and was once called a micromodule.

Problems to be Solved by the Invention The purpose of configuring multiple circuit boards in layers is to increase the mounting density of circuit components and maintain high reliability.In the first multilayer wiring board, the surface layer, that is, the upper・It is impossible or difficult to place components other than on the lower layer, and it is also expensive.The structure that connects the second four pillars is only a mechanical connection, and the electrical connection is made using separate leads. This has to be done using wires or connectors.The third micromodule configuration has the drawback of requiring soldering of a large number of leads or terminals, is not a mass-produced method, and is therefore expensive to manufacture. .Also, there is a drawback that the lead is bent and the shape retention of the lead is not good.

Means for Solving the Problems In the present invention, chip-type electronic components are mounted on one board surface at the same time as other top-mounted components are mounted on the bottom first mounting board, and after mounting them, another The top mounting board is stacked as the second mounting board, and for this double structure, -
Moreover, heating for solder reflow can be applied from both the top and bottom sides. At that time, the same solder paste that is printed or dispensed on the first and second mounting boards is printed in advance on the lower surface of the second mounting board, that is, on the electrode contact part of the chip type electronic component. .

Function: With the configuration according to the present invention, solder pastes having the same melting point can be used on the first substrate surface, the second substrate surface, and the electrode surface of the chip type electronic component, and furthermore, soldering can be performed in multiple layers.

This is because loosening of the soldered portion due to soldering is avoided, and a high degree of reliability of soldering can be maintained. Furthermore, since the soldering furnace passes through the circuit only once, it is possible to minimize the frequency of applying thermal shocks exceeding 125° C. to the board and mounted components. As for the substrate material,
ceramic.

Rigid printed wiring board laminates made of glass, glass epoxy, paper epoxy, paper phenol, paper polyester aramid epoxy, glass polyimide, etc. can be applied, as well as foil or powdered materials such as silver, copper, and gold. Conductors can be formed on the surfaces of these substrates. These materials exist on the market as having heat resistance to soldering temperatures of 200 to 300° C. and good wettability to enable soldering.

Embodiment FIG. 1 shows an embodiment of the present invention. 1 is the first mounting board, 2
The conductor chip 3 interposed on the second mounting board is placed on the first mounting board 1 together with other surface-mounted components, so-called chip-type electronic components 8, in alignment with the conductor 4 and the solder 5. The upper surface of the conductor chip 3 is brought into contact with the solder 9 printed on the conductor surface 9 of the second mounting board 2 prepared separately. The height H of the conductor chip 3 determines the mounting gap J between the first mounting board 1 and the second mounting board 2. For example, if a ceramic capacitor chip with a height of 1.25 mm is mounted on the first mounting board 1, and the height H of the conductor chip is set to 1.50 mm,
A gap of 5 mm is obtained as a physical gap between the first mounting board 1 and the second mounting board 2. The gap between the first mounting board 1 and the second mounting board 2 is approximately the height of the conductor chip 3 (1.50 mm).
), the thickness of conductor 8 and conductor 4 (15 μm x 2), and the thickness of solder 5 and solder 9 (15 μm x 2),
It will be about 1.56 minutes. If the substrate thickness is 1.0mm,
The center gap between the substrates is 2.56 m++++. The solder may be tin-lead (weight ratio 63-37), which is often used, but sometimes low-temperature solder containing bismuth, solder containing silver, etc.
Solder is also used. As for the heating source, it is preferable to use either the upper or lower heating source (the one that heats the upper and lower simultaneously has good temperature distribution.The type of heat source may be infrared, direct infrared, or electric heating, but for example, 215°C ± 5°C). It is desirable to use a conveying device that can control soldering execution conditions of 15±1 seconds.

Effects of the Invention According to the present invention, firstly, multiplexing of mounting boards can be achieved by using lead wires,
This can be done without using terminals, so there is no need to worry about irregular positions or
Second, the conductor chip can be placed anywhere in a small area of the circuit surface, and does not need to be limited to the edges. Therefore, it is easy to route the wiring on the first and second mounting boards. can be shortened. Third, since the connection can be performed simultaneously with many surface mounting operations, the number of steps is not increased, and reheating during soldering does not cause loosening of the solder or thermal trapping of the components.

Therefore, high-density packaging can be carried out at low cost and with high reliability.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views showing the state before and after assembly of the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... First mounting board I board, 2... Second mounting board, 3... Conductor chip, 4... Conductor of first board, 5・・・・・・Solder printed on 4, 6
...Conductor of second board, 7...Solder printed on 6, 8...Surface mounting component to be mounted on first mounting board, 9... The electrode formed at 8, 10.
...Surface mounting component mounted on the second mounting board. Name of agent: Patent attorney Toshio Nakao and 1 other person/---;
1-/Practical board 2-Last board 2-Full-length board 3-Conductor chip 4-1 printed on conductor S-4 of 1 base 6-2nd base conductor H--1 thick chip NoshimasaJ-11 Diagram 2 of the arrangement gap of the basal branch of the fruit table

Claims (1)

[Claims] The insulating rectangular parallelepiped has a printed electrode dedicated to soldering, and each electrode of a chip-type electronic component is firmly connected to the electrode, and multiple circuit boards are stacked and integrated via the chip-type electronic component. multiplexed circuit board.