JPH03278593A - Circuit board - Google Patents

Abstract

PURPOSE:To make it possible to obtain a highly reliable circuit board capable of reducing its film thickness and being free of off-set and cracks of wiring patterns by forming a circuit board with a board raw material made of thermally deformable resin, and a circuit raw material which forms wiring patterns with conductors where conductive substance-made powder is dispersed in the thermally deformable resin. CONSTITUTION:A circuit board 10 comprises a board element assembly 11 made of thermal plasticity resin and a circuit raw material 12 where wiring patterns are printed- formed with conductors in which metal powder is dispersed in the thermally deformable resin. On one side of this board raw material 11 are printed connection electrodes for other circuit boards or mounted components. Circuit raw materials 12 are respectively polymerized on one side of a plurality of board raw materials 1 so that the board raw material 11 may be laminated and heated and contact-bonded with a heating press so that a plurality of circuit boards 10 may be laminated and bonded integrally. The lamination bonding by this heating contact bond produces the surface of the circuit element assemblies 12 on the same level of the board element assemblies 11 so that they may be integrally bonded under an exposed state, which makes it possible to form the circuit elemental assemblies 10 in several layers lamented into one piece.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a circuit board used in electronic equipment, etc., and relates to a circuit board used in electronic devices, etc., which increases the packaging density by integrally bonding a circuit board body into multiple layers. related to things.

(Prior art) In recent years, with the miniaturization and diversification of electronic devices, there has been a demand for the integration of multiple circuit boards. Glass made by impregnating glass fiber with thermosetting resin such as epoxy resin.
Copper foil is heat-pressed onto one or both sides of the epoxy resin substrate 1, the copper foil surface of the substrate 1 is chemically etched to form the wiring pattern 2, and the intersection of the wiring patterns 2 and 3 is electrically insulated. An insulating layer 4 is formed with a resin paste having a
, 3, a structure is known in which the wiring pattern 2 is insulated and connected to the crossing wiring pattern 3 across the outer surface of the insulating layer 4 to achieve high density.

In addition, as shown in FIG. 8, copper foil is heat-pressed onto one surface of a glass/epoxy resin substrate 1, which is formed by impregnating glass fibers woven into a cloth shape with a thermosetting resin such as epoxy resin, and A wiring pattern 2 is formed by chemically etching the copper foil surface of the board 1, and then glass fibers woven into a cloth are impregnated with a thermosetting resin such as an epoxy resin on the surface of the board 1 on which the wiring pattern 2 is formed. A circuit board having a structure in which a semi-cured prepreg 6 molded by polymerization is polymerized, a copper foil is placed on the surface of this sheet-like prepreg 6, pressure pressed, and a wiring pattern 7 is formed by etching the copper foil. It has been known.

(Problems to be Solved by the Invention) In the circuit board having the structure shown in FIG. The wiring pattern 2 is insulated from the wiring pattern 3 crossing the outer surface of the insulating layer 4.
Due to the structure of connecting the jumper wires, abrupt rising and falling steps are formed in the insulating layer 4 when printing the jumper wires, resulting in inconveniences such as breakage and cracks during the printing and curing of the jumper wires. This problem often occurs, making it difficult to control printing conditions.Also, since the insulating parts 4 at the intersections of the wiring patterns are formed by thick-film printing using insulating paste, there is a problem in that there is a limit to how thin the wiring pattern can be made. was there.

In addition, in the circuit board having the structure shown in FIG. 8, the prepreg 6 is polymerized on the surface of the wiring pattern 2 of the substrate 1, and the wiring pattern 7 is formed on the surface of the prepreg 6, so that each layer is sequentially laminated. There are problems in that there is a limit to how thin the film can be made, and the manufacturing process is complicated because etching of the copper foil is required for each layer.

The present invention has been made in view of the above-mentioned problems, and consists of a substrate element made of a heat-deformable resin and a circuit element in which a wiring pattern is formed using a conductor made of a conductive substance powder dispersed in the heat-deformable resin. By forming the circuit board body in this way, it is possible to immerse the circuit body into the board body and make it a thin film, and there is no breakage or cracks in the wiring pattern, resulting in a highly reliable circuit board. It provides:

(Structure of the Invention) (Means for Solving the Problems) The circuit board of the invention according to claim 1 includes a substrate body made of a heat-deformable resin, and a conductive substance powder dispersed in the heat-deformable resin. a circuit element on which a wiring pattern is formed using a conductive material, the circuit element is heat-pressed onto at least one surface of the substrate element, and at least a portion of the circuit element is immersed in the substrate element. A plurality of circuit board bodies are laminated by heating and pressure bonding to form a plurality of circuit board bodies that are integrally bonded with their surfaces exposed.

The circuit board of the invention according to claim 2 comprises: a board element made of a heat-deformable resin; and a circuit element in which a wiring pattern is formed using a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin. A circuit board which is integrally bonded with the circuit element on at least one surface of the substrate element by heat-pressing the circuit element and immersing at least a portion of the circuit element into the substrate element with the surface exposed. The circuit board body is formed by laminating a plurality of layers by heat and pressure bonding, and the board body of the laminated circuit board body is thinned at the intersection portion of the circuit body.

The circuit board of the invention according to claim 3 comprises: a board element made of a heat-deformable resin; and a circuit element in which a wiring pattern is formed using a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin. The circuit element is heat-pressed onto the lower (both sides) of the substrate element, and the circuit element is immersed at least partially into the substrate element to be integrally bonded with the surface exposed. A plurality of circuit board bodies are laminated by heat and pressure bonding in a plurality of layers, and the circuit elements of the laminated circuit board bodies are made thinner at the intersection portions of the circuit elements.

(Function) In the circuit board of the invention according to claim 1, the circuit board bodies to be laminated include a board body made of a heat-deformable resin, and a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin. The circuit element is immersed into this substrate element by heat compression bonding, and the circuit element is made into a thin film, and the wiring pattern is integrated, which prevents breaks and cracks from occurring. do not have.

In the circuit board of the invention according to claim 2, the thickness of the board element is thinner at the intersection of the wiring patterns of the circuit board body, and there is no breakage or cracking of the wiring pattern, making it possible to make the film thinner. becomes.

In the circuit board according to the third aspect of the invention, the thickness of the intersection of the circuit elements of the laminated circuit board bodies can be reduced at the intersection of the wiring patterns of the circuit board body, and the thickness of the intersection of the circuit elements of the laminated circuit board body can be reduced, thereby preventing breakage and cracks in the wiring pattern. Therefore, it is possible to make the film thinner.

(Embodiment) Next, the configuration of an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Reference numeral 10 denotes a circuit board body, and the circuit board body 10 includes a substrate body 1 made of a heat deformable resin, for example, a thermoplastic resin, and a conductive substance, for example, in the heat deformable resin, for example, a thermoplastic resin. It is composed of a circuit element I2 on which a wiring pattern is printed using a conductor in which metal powder is dispersed.Furthermore, on one side of this circuit element 11, there are electrodes (not shown) for connecting other circuit boards or mounted components. ) is printed.

Then, each of the circuit elements 12 is superposed on one surface of the plurality of substrate elements 11, and the plurality of substrate elements 11 are laminated and heat-pressed at a constant pressure using a fixed plate of a heat press machine to form a plurality of circuit elements 12. The circuit board body 10 is integrally laminated and bonded. By this laminated bonding by heat and pressure bonding, each circuit element 12 is bonded to the substrate element 1.
1, the circuit element body 11 flows laterally as the circuit element body 12 is immersed, and the surface of the circuit element body 12 becomes flush with the surface of the circuit element body 11, and is exposed. The circuit board body 10 is integrally laminated into a plurality of layers.

The thickness of the circuit board formed in this way is 1
The sum is 1, and the circuit element 12 forming the conductive pattern has no rejected unevenness or step.

Then, the heat deformable resin of the substrate body 11 and the circuit body 12
Resins with different curing temperatures from the heat deformable resins, i.e.
By setting the curing temperature of the resin of the circuit element 12 lower than that of the resin of the circuit element 11, the circuit element 12 is immersed into the substrate element 11 without being deformed.

Next, another embodiment will be described with reference to FIGS. 3 and 4.

As shown in the above embodiment, the circuit board body 10 is made up of a board body 11 made of a thermodeformable resin and a circuit body 12 on which a wiring pattern is printed and formed using a conductive material dispersed in the thermodeformable resin. Furthermore, an electrode (not shown) is printed on one surface of the substrate element 11. Then, each of the circuit elements 12 is superposed on one surface of the plurality of substrate elements 11, and the plurality of substrate elements 11 are laminated and heat-pressed at a constant pressure using a fixed plate of a heat press machine to form a plurality of circuit elements 12. The circuit board bodies IO are integrally stacked and bonded. Through this laminated bonding by heat and pressure bonding, each circuit element 12 is immersed into the substrate element II, and the substrate element 11 flows laterally as the circuit element 12 is immersed, so that the surface of the circuit element 12 becomes the substrate element. Each substrate element 11 is formed so that the part where the circuit element 12 is formed is thinner than the other part, and furthermore, each circuit element 11 is formed to be thinner than the other part. The substrate element 11 is flowed laterally at the intersection between the upper and lower positions of the element 12,
The thickness of this board body 11 is formed to be thinner than the non-intersecting portions of the circuit elements I2, and the inner circuit elements 12 are formed at the intersections with the upper circuit elements 12.
The circuit board body 1G is further recessed due to the protrusion of the circuit board 1G, and the circuit board body 1G is integrally laminated into a plurality of layers.

The thickness of the circuit board thus formed is the sum of each board element 11 and each circuit element 12, and the circuit element 12 forming the conductive pattern is free from rejected irregularities and steps.

Then, the heat deformable resin of the substrate body 11 and the circuit body 12
Resins with different curing temperatures from the heat deformable resins, i.e.
By making the curing temperature of the resin of circuit element 2 lower than that of the resin of the circuit element 11, the circuit element 12 can be easily deformed and immersed in the circuit element 11.

Next, another embodiment will be described with reference to FIGS. 5 and 6.

Similar to the embodiment described above, the circuit board body 10 includes a board body 11 made of a thermodeformable resin, and a circuit body 12 on which a wiring pattern made of a conductive material dispersed in a thermoplastic resin is printed. Furthermore, an electrode (not shown) is printed on one surface of the substrate element 11. Then, each of the circuit elements 12 is superposed on one surface of the plurality of substrate elements 11, and the plurality of substrate elements II are laminated and heat-pressed at a constant pressure using a fixed plate of a heat press machine to form a plurality of circuit elements 12. The circuit board body 10 is integrally laminated and bonded. By this laminated bonding by heat and pressure bonding, the circuit element body 12 is immersed into the substrate body 11, and the circuit element body 1] flows laterally due to the insertion of the circuit element body 12, and the surface of the circuit element body 12 is brought into contact with the substrate body 11. The circuit elements 12 are connected integrally in an exposed state flush with the surface of the circuit elements 12, and the circuit elements 12
However, this circuit element body 12 is formed thinner than other parts that are not crossed, and the circuit board body 10 is integrally laminated into a plurality of layers.

The thickness of the circuit board formed in this way is the sum of each board element 11 and each circuit element 12, and the thickness of the circuit element 12 forming the conductive pattern on the front side is formed by the rejected irregularities and steps. Not done.

Then, the heat deformable resin of the substrate body 11 and the circuit body 12
Resins with different curing temperatures from the heat deformable resins, i.e.
By setting the curing temperature of the resin of the circuit element body 12 higher than that of the resin of the circuit element body 11, the circuit element body 12 is immersed into the circuit element body 12 without being deformed.

In the embodiment, from the surface of the substrate body 11 to the circuit body 12
Although the surfaces of the circuit element 12 are formed on the same plane so as not to protrude, a part of the circuit element 12 is partially immersed in the substrate element 11 so that the circuit element 12 protrudes somewhat from the surface of the substrate body 11. You can also.

Further, the circuit element 12 can be provided on both sides of the substrate element 11, and wiring patterns can be formed on both sides.

Further, in the above embodiments, the circuit board body 10 is described as having a two-layered structure, but it is not limited to a two-layer structure, and can be formed in a plurality of layers.

Further, the heat deformable resin forming the substrate body 11 and the circuit body 12 may be a thermosetting resin or a thermosoftening resin, and the heat deformable resin may be, for example, polycarbonate or polyvinyl chloride. , polystyrene, saturated polyester, polystyrene, polypropylene, polyphenylene oxide, polysulfone, polyphenylene sulfide, polyacetal, polyamide, etc. are applicable.

Furthermore, the circuit element 12 is made of a composition obtained by kneading fine metal powder such as silver, copper, nickel, gold, platinum, aluminum, etc., using a heat deformable resin as a binder, and adding a solvent as necessary. It is formed by printing a thick film conductive paste.

〔Effect of the invention〕

According to the present invention, a circuit board body is formed by a substrate body made of a heat-deformable resin and a circuit body on which a wiring pattern is formed using a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin. By forming this, it is possible to immerse the circuit element into the substrate element and make it a thin film, and there is no breakage or cracking in the wiring pattern, resulting in a highly reliable circuit board with high packaging density. It is something.

Further, according to the invention described in claim 2, the thickness of the substrate body becomes thinner at the intersections of the wiring patterns of the circuit board body, and there is no breakage or cracking of the wiring patterns, and the film thickness can be further reduced. It is possible.

According to the third aspect of the invention, at the intersection of the wiring patterns of the circuit board body, the thickness of the intersection of the circuit elements of the laminated circuit board body can be reduced, and breakage and cracks in the wiring pattern can be reduced. This makes it possible to make the film thinner.

[Brief explanation of drawings]

FIG. 1 is a front view showing the manufacturing process of a circuit board according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional front view of the same circuit board, and FIG.
The figure is a front view showing the manufacturing process of a circuit board showing another embodiment of the present invention, FIG. 4 is a longitudinal sectional front view of the same circuit board, and FIG. Figure 6 is a front view showing the manufacturing process; Figure 6 is a vertical cross-sectional view of the same circuit board;
The figure is a longitudinal sectional view of a conventional circuit board, and FIG. 8 is a longitudinal sectional view of another conventional circuit board. 10... Circuit board body, 11... Board element body, 12... Circuit element body.

Claims (3)

[Claims] (1) Consisting of a substrate element made of a heat-deformable resin, and a circuit element formed with a wiring pattern made of a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin, at least The circuit element body is heat-pressed on one side, and the circuit element body is immersed at least partially into the board element body to be integrally bonded with the surface exposed. Multiple layers of the circuit board body are laminated by heat-press bonding. A circuit board characterized in that: (2) Consisting of a substrate element made of a heat-deformable resin and a circuit element in which a wiring pattern is formed using a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin, at least The circuit element body is heat-pressed on one side, and the circuit element body is immersed at least partially into the board element body to be integrally bonded with the surface exposed. Multiple layers of the circuit board body are laminated by heat-press bonding. A circuit board, characterized in that the board elements of the laminated circuit board bodies have a reduced thickness at the intersection portions of the circuit elements. (3) Consisting of a substrate element made of a heat-deformable resin and a circuit element in which a wiring pattern is formed using a conductor in which powder of a conductive substance is dispersed in the heat-deformable resin, at least The circuit element body is heat-pressed on one side, and the circuit element body is immersed at least partially into the board element body to be integrally bonded with the surface exposed. Multiple layers of the circuit board body are laminated by heat-press bonding. A circuit board, characterized in that the circuit elements of the laminated circuit board bodies have a reduced thickness at the intersection portions of the circuit elements.