JPH01202898A - Multilayer circuit board - Google Patents

Abstract

PURPOSE:To simplify circuit modification and reduce the cost, by laminating a Y-axis pattern layer and X-axis pattern layer on the backside of a mother circuit board. CONSTITUTION:Y-axis conductor pattern 15 of a Y-axis pattern layer 10 and X-axis conductor pattern 25 of a X-axis pattern layer 20 crosses at their lattice intersecting points, and the positions of the intersecting points correspond to those of through holes 2. the Y-axis conductor pattern 15 and the X-axis conductor pattern 25 are insulated by insulating films 16, 27. In addition, the Y-axis conductor pattern 15 and the through holes 2 are insulated each other by an insulating film 17. And, when lattice intersecting points are selectively pushed and heated, only the insulating films 16, 17, 26, 27 are melted and removed without damaging the frame rims of windows 12, 22 of polyimide films 11, 21, and the Y-axis conductor pattern 15 and the X-axis conductor pattern 25 are thermally bonded, enabling conduction between them. Therefore, by selecting intersecting points of the lattice and connecting the Y-axis conductor pattern 15 and the X-axis conductor pattern 25 at the positions of the intersecting points of the lattice, a plurality of through holes 2 at the desired positions can be connected. Thus, a multilayer circuit substrate suitable for general purposes is obtained.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a multilayer circuit board in which a pattern layer is attached to the back side of a mother circuit board. , a polyimide film with windows arranged at each grid intersection point, a Y-axis conductor pattern arranged on the Y-axis grid on the back side of the polyimide film, and the entire surface of both sides of the polyimide film including the surface of the Y-axis conductor pattern. A Y-axis pattern layer consisting of an insulating film that is in close contact with a low heat-resistant temperature, a polyimide film with windows arranged at each grid intersection point, and an X-axis conductor pattern arranged on the X-axis grid on the back side of the polyimide film. and an insulating film with low heat-resistant temperature that is in close contact with both surfaces of the polyimide film including the surface of the X-axis groove pattern.
The axial pattern layer is laminated on the back surface of the mother circuit board, which has through holes at desired positions of the grid intersection points, and the selected grid intersection points and the grid intersection points corresponding to the through holes are heated and pressed. The Y-axis conductor pattern and the X-axis groove pattern, or the Y-axis conductor pattern, the X-axis groove pattern, and the through hole are bonded together by thermocompression.

[Industrial application field]

The present invention relates to a multilayer circuit board in which a pattern layer is attached to the back surface of a mother circuit board.

[Conventional technology]

For the multilayer circuit board, a desired number of resin copper-clad laminates are laminated, and a desired conductor pattern is etched on both sides or both sides and the inner layer.The multilayer resin laminate is then laminated with a ceramic board and a ceramic board is laminated on both sides or both sides and the inner layer. There is also a multilayer ceramic substrate on which a desired conductor pattern is formed.

These circuit boards connect conductor patterns in each layer via through holes.

In any multilayer circuit board, the shape of the conductor pattern is determined at the time of circuit design, and the conductor pattern of each layer is formed in accordance with the shape.

[Problem to be solved by the invention]

Therefore, the conventional multilayer circuit board has a problem in that it is very difficult to change the circuit after it is manufactured, and flexibility in changing the circuit is poor.

Furthermore, since the inner layer has a conductive pattern, the structure is complicated and there is a risk that the cost will be high.

The present invention was created in view of these points, and an object of the present invention is to provide a versatile, low-cost multilayer circuit board that allows easy circuit changes.

[Means to solve the problem]

In order to achieve the above object, the present invention, as illustrated in FIG. The Y-axis groove pattern 15 disposed on the back surface of the polyimide film 11 and the low temperature-resistant insulating films 16 and 17 that are in close contact with both surfaces of the polyimide film 11 including the surface of the Y-axis groove pattern 15. Configure.

In addition, the X-axis pattern layer 20 is provided with windows 22 at each grid intersection.
A polyimide film 21 is arranged on the polyimide film 21, and a
It is composed of the 1b conductor pattern 25 and low temperature resistant insulating films 26 and 27 that are closely adhered to both surfaces of the polyimide film 21 including the surface of the X-axis conductor pattern 25.

The mother circuit board 1 has a desired circuit pattern on its front surface, and has through holes 2 at desired positions of grid intersections that communicate with the back surface. On the back side of this mother circuit board 1, a Y-axis pattern 1i1
0 and the X-axis pattern layer 20 are laminated, and the selected lattice intersection points and the lattice intersection points corresponding to the through holes 2 are heated and pressed to form the Y-axis conductor pattern 7-15 and the X-axis conductor pattern 25, or the Y-axis Groove pattern 15. x-axis conductor pattern 25. and the through hole 2 are bonded together by thermocompression.

[Effect]

According to the present invention, the Y-axis groove pattern 15 of the Y-axis pattern layer 10 and the X-axis conductor pattern 2 of the X-axis pattern layer 20
5 are orthogonal to each other at the grid intersection, and the intersection corresponds to the through hole 2 position. In addition, the Y-axis groove pattern 15
and the X-axis conductor pattern 25 are orthogonal to each other in an insulated state by the insulating films 16 and 27, and the through hole 2 is insulated by the insulating film 17.
is insulated by

Since the polyimide films 11 and 12 are polyimide resins, they have a high heat resistance and a high melting temperature.

On the other hand, insulating film 16.1? , 26.27 has low heat resistance and therefore melts at a relatively low temperature.

Therefore, when the selected lattice intersection points are heated and pressed, the frame edge of the window 12.22J of the polyimide film 11.21 is not damaged, and the insulating film 16.1? , 26 and 27 are melted and removed, and the Y-axis groove pattern 15 and the X-axis groove pattern 25 are thermocompressed and brought into electrical continuity.

In addition, when the grid intersection points corresponding to the through holes 2 are heated and pressed, the insulating film 16.1? , 26 and 27 are melted to form the Y-axis groove pattern 15. The X-axis path body pattern 25 and the through hole 2 are bonded by thermocompression, and are in a conductive state.

Therefore, by appropriately selecting grid intersection points and connecting the Y-axis groove body pattern 15 and the X-axis groove body pattern 25 at the grid intersection positions, it is possible to connect a plurality of through holes provided at desired positions. can.

That is, the Y-axis pattern ii attached to the back surface of the mother circuit board 1
With the o and x-axis pattern layers 20, a circuit can be configured as desired, making it a versatile multilayer circuit board.

〔Example〕

The present invention will be specifically described below with reference to the drawings. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a perspective view showing an embodiment of the present invention in separated form;
Figures 2 (a) and (b) are cross-sectional views of the thermocompression bonding process of the present invention, Figure 3 is a diagram of an embodiment of the present invention, +8) is a plan view as viewed from the back, and (b) is a cross-sectional view of the thermocompression bonding process of the present invention. The chain line X shown in the figure and Fig. 3(a)
- It is a sectional view of the X part.

In FIG. 1, reference numeral 1 denotes a mother circuit board made of, for example, ceramic, on the surface of which a desired circuit pattern is provided and further chip-shaped circuit components are mounted.

The mother circuit board l is provided with through holes 2 communicating with the back surface at desired positions of grid intersections of predetermined grid dimensions. This through hole 2 protrudes toward the back side by about 30 μm, for example, to form a through hole protrusion 2A.

Further, on the back side of the mother circuit board 1, a through hole protrusion 2A is provided.
A dielectric protrusion 3 is provided at each lattice intersection except for . These dielectric protrusions 3 are formed by screen printing dielectric paste, and their thickness is approximately equal to the height of the through-hole protrusions 2A.

Further, at the four corners of the back surface of the mother circuit board 1, circular guide metal films 4 formed by screen printing a conductive paste are provided. The thickness of this guide metal film 4 is also approximately 30 μm, which is approximately equal to the height of the through-hole protrusion 2A.

Reference numeral 11.21 is a rectangular polyimide film having a thickness of, for example, about 50 μm and having the same shape as the mother circuit board 1, and has a heat resistance temperature of 300° C. or more.

The polyimide film 11 is provided with rectangular windows 12 whose negative side is approximately equal to the width of the conductor pattern at each grid intersection point of a predetermined grid size. Further, the polyimide film 21 is provided with windows 22 having the same shape as the windows 12 at grid intersections.

On each Y-axis grating on the back surface of the polyimide film 31, a Y-axis groove pattern 15 made of W4 foil having a width of 30 μm and a thickness of 70 μm, for example, is provided.

This Y-axis groove pattern 15 is made of polyimide film 11.
It can be easily obtained by etching a copper foil adhered to the surface.

Further, guide holes 13 are provided at the four corners of the polyimide film 11, and a metal foil 14 made of copper foil or the like is provided on the back side of the polyimide film 11 corresponding to each guide hole 13.

The back side of the polyimide film 11, including the surfaces of the Y-axis groove pattern 15 and the metal foil 14, is made of a material having a thin film thickness of about 30 μm and having low heat resistance and temperature resistance such as polyurethane resin (with a heat resistance temperature of 80°C to 90°C). ) is pasted onto the insulating film 16. Further, an insulating film 17 having a low heat resistance is similarly pasted on the surface of the polyimide film 11.

Therefore, the guide metal film 4 of the mother circuit board l has the guide hole 13 corresponding to the through-hole protrusion 28 and the dielectric protrusion 3.
The insulating film 17 at the window 12 portion is recessed more than the other portions and directly adheres to the metal foil 14 or the Y-axis groove pattern 15.

That is, the Y-axis pattern layer 10 is a polyimide film 11. having windows 12. A large number of parallel Y-axis groove patterns 15,
This is a film in which the insulating films 16 and 17 on both sides are closely adhered and integrated.

On each X-axis grating on the back surface of the polyimide film 21, an X-axis groove pattern 25 made of copper foil and having a width of 30 μm and a thickness of 70 μm, for example, is provided.

Further, guide holes 23 are provided at the four corners corresponding to the guide holes 13, and metal foils 24 made of copper foil or the like are provided on the back side of the polyimide film 21 corresponding to the respective guide holes 23.

On the back surface of the polyimide film 21 including the surfaces of the X-axis groove pattern 25 and the metal foil 24, an insulating film 26 having a thin film thickness of about 30 IIm and having low heat resistance is pasted. Furthermore, an insulating film 27 having low heat resistance is similarly pasted on the surface of the polyimide film 21.

Therefore, the guide metal film 4 of the mother circuit board 1 has guide holes 23 corresponding to the through-hole protrusions 2A and the dielectric protrusions 3.
The insulating film 27 at the window 22 portion is recessed more than the other portions and directly adheres to the metal foil 24 or the X-axis groove pattern 25.

That is, the X-axis pattern layer 20 includes a polyimide film 21 having windows 22, a large number of parallel X-axis groove patterns 25,
This is a film in which the insulating films 26 and 27 on both sides are in close contact and integrated.

The Y-axis pattern layer 10 and the X-axis pattern layer 20 configured as described above are laminated on the back surface of the mother circuit board l, the guide hole 13 is formed in the guide metal film 4, and the metal foil 14 protrudes from the back surface of the guide hole 13. After inserting the guide holes 23 into each and aligning the positions, the metal foil 24 portion of the X-axis pattern layer 20 is heated and pressed using a thermocompression bonding electrode.

Thereafter, the through holes 2 and the selected portions of the dielectric protrusions 3 are heated and pressed to connect the through holes provided at desired positions.

In detail, the Y-axis pattern jiJ10. Since the X-axis pattern layer 20 is aligned with the back surface of the mother circuit board l by the guide hole, the X-axis pattern layer 20 is aligned with the back surface of the mother circuit board l. Y-axis pattern layer 1
0. and the X-axis pattern layer 20 are overlaid with matching lattices.

Therefore, FIG. 2 (a) shows the mother circuit board upside down.
As shown in FIG. 1, a window 12 of the Y-axis pattern layer IO is placed directly above the through-hole protrusion 2 protruding from the back surface of the mother circuit board l.
, and the windows 22 of the X-axis pattern layer 20 are located. Inside the window 12, a Y-axis groove pattern 15 whose upper and lower surfaces are sandwiched between insulating films 16 and 17 runs, and inside the window 22,
An X-axis groove pattern 25, whose upper and lower surfaces are sandwiched between insulating films 26 and 27, runs.

Therefore, as shown in FIG. 2), if the thermocompression electrode 30 is used to press the window 22 portion corresponding to the through hole 2,
The insulating films 27, 26, 17, and 16 in the window 22.12 portion are melted and removed, respectively, and the through-hole protrusion 2A and the Y-axis groove pattern 15. The X-axis groove pattern 25 is bonded by thermocompression to become integrated and electrically conductive.

Further, although not shown, the selected lattice intersection point, that is, the window 22 portion corresponding to the selected dielectric protrusion 3 is connected to the thermocompression bonded electrode 30.
When pressed, the insulating film 27, 26 .
17 and 16 are respectively melted and removed, and the Y-axis groove pattern 15 and the X-axis groove pattern 25 are thermocompressed and electrically connected.

An example of the circuit of the multilayer circuit board obtained as described above is shown in FIG.

In FIG. 3, the guide metal film 4. A Y-axis pattern layer 10 is formed on the back surface of the mother circuit board 1 by thermocompression-bonding metal foils 14 and 24.
The X-axis pattern 1 is placed on the Y-axis pattern layer 10.
! 20 means close contact.

In order to fully connect the through holes 2-1 and 2-2 on different grids on the upper part of the mother circuit board l, the through holes 2-1 and 2-2 are bonded by thermocompression. The through-hole conductor, the Y-axis groove pattern 15 and the X-axis groove pattern 25 are connected.

Then, a lattice intersection 3- between the X-axis lattice passing through the through hole 2-1 and the Y-axis lattice passing through the through hole 2-2.
1 is thermocompressed to connect the Y-axis groove pattern 15 and the X-axis groove pattern 25.

In addition, in order to connect the through holes 2-3 and 2-4 located on different grids at the lower left of the mother circuit board 1, the respective through holes 2-3 and 2-4 were bonded by thermocompression. Through-hole conductor, Y-axis groove pattern 15
and the X-axis groove pattern 25, and through-hole 2-
The Y-axis groove pattern 15 and the X-axis groove pattern 25 are connected by thermocompression bonding the lattice intersection point 3-3 between the Y-axis grating passing through the through hole 2-4 and the X-axis grating passing through the through hole 2-4. ing.

Furthermore, in order to connect the through hole 2-5 and the other through hole 2-6 on the same X-axis conductor pattern 25 as the through hole 2-3, each through hole 2-5, 2-6 Heat-bond the parts and make a through-hole conductor, Y
The axial conductor pattern 15 and the X-axis groove pattern 25 are connected, and the lattice intersection points 3-5 of the X-axis lattice passing through the through-hole 2-5 and the Y-axis lattice passing through the through-hole 2-6 are bonded by thermocompression. Then, the Y-axis conductor pattern 15 and the X-axis groove pattern 2
5 is connected.

In addition, through hole 2-3 and through hole 2-5 are as follows.
Since they are on the same X-axis conductor pattern 25, a cut portion 40 is provided between the through hole 2-3 and the through hole 2-5, and the Y-axis pattern layer 10 and the X-axis pattern layer 20 are cut. The holes 2-3 and 2-5 are prevented from being electrically connected.

Although the dielectric protrusions shown in the embodiments are not necessarily necessary, providing the dielectric protrusions increases the reliability of thermocompression bonding work.

In the illustrated example, the circuit pattern IA is provided only on the front surface of the mother circuit board 1, but it goes without saying that the present invention can be applied to a mother circuit board 1 in which circuit patterns are formed on both the front and back surfaces.

Further, the mother circuit board is not limited to a ceramic board, but can be applied to a resin copper-clad laminate.

〔Effect of the invention〕

As explained above, the present invention is a multilayer circuit board in which a Y-axis pattern layer and an It has excellent practical effects such as low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention in separated form, FIG. 2 (al) and (b) are cross-sectional views of the thermocompression bonding process of the present invention, and FIG. (a) is a plan view as viewed from the back. (b) is a cross-sectional view. In the figure, l is a mother circuit board, 2.2-1.2-2.2-3.2-4.2- 5.2-6
2A is a through hole, 2A is a through hole protrusion, 3 is a dielectric protrusion, 4 is a guide metal film, 10 is a Y-axis pattern layer, 20 is an X-axis pattern layer, 11 and 21 are polyimide films, 12 and 22 are windows , 13 and 23 are guide holes, 14 and 24 are metal foils, 15 is a Y-axis conductor pattern, 25 is an X-axis conductor pattern, 16, 1? , 26.27 indicates an insulating film. Side (b) Cross-sectional opening of the necessary square paper '#2 Mouth

Claims (1)

[Scope of Claims] A polyimide film (11) with windows (12) arranged at each grid intersection point, a Y-axis conductor pattern (15) arranged on the Y-axis grid on the back side of the polyimide film (11),
and a Y-axis pattern layer (10) consisting of a low temperature-resistant insulating film (16, 17) that is in close contact with the entire surface of both surfaces of the polyimide film (11), including the surface of the Y-axis conductor pattern (15). and a polyimide film (21) with windows (22) arranged at each grid intersection, an X-axis conductor pattern (25) arranged on the X-axis grid on the back side of the polyimide film (21), and the X-axis conductor. An X-axis pattern layer (2) consisting of low temperature resistant insulating films (26, 27) closely adhered to both surfaces of the polyimide film (21) including the surface of the pattern (25).
0) has a through hole (2) at the desired position of the grid intersection point,
The Y-axis conductor pattern (15) and the
The axial conductor pattern (25) or the Y-axis conductor pattern (1
5) A multilayer circuit board characterized in that the X-axis conductor pattern (25) and the through hole (2) are bonded together by thermocompression.