JP3482657B2 - Circuit board and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board on which a semiconductor LSI, chip parts, etc. are mounted and which are interconnected.
And a manufacturing method thereof.

[0002]

2. Description of the Related Art With the miniaturization and diversification of electronic equipment, multilayer boards have come to be widely used as boards capable of high-density wiring and high-density mounting. Furthermore, it is expected that demand will increase in the future as a mounting substrate for semiconductor bare chips and narrow-pitch semiconductor ICs, and it is considered necessary to provide a method for manufacturing a multilayer substrate that facilitates fine wiring and has high reliability. Attention is also being paid to flexible circuit boards because they also serve as flexibility and connector cables. An example of a conventional flexible multilayer circuit board is shown in FIG. The manufacturing method will be described below. First, a film 1 made of polyimide or the like is provided with copper plating or copper foil on both sides. Next, a pattern 2 is formed by photolithography, etching, or the like. Repeat this as needed. Next, the patterned polyimide film and the unpatterned polyimide film with the adhesive 3 are alternately laminated. After the adhesive is hardened, the through hole 4 is opened. Copper plating is applied to the through-hole holes, and a multilayer substrate is completed by forming a surface layer pattern, an overcoat, a coverlay, or the like.

[0003]

However, plating increases the number of steps and costs for equipment and environmental measures, resulting in an increase in product cost. In addition, since an adhesive or the like is used to bond the films to each other, poor connection of through-hole plating is likely to occur, resulting in poor yield. Further, when forming a conductor pattern, there are many steps in forming a resist pattern using a dry film or the like and etching the conductor pattern. Therefore, a method of forming a pattern by a simpler method is desired.

[0004]

In order to solve the above-mentioned problems , conductors having a predetermined thickness are formed on both surfaces of a thermoplastic resin film.
Conductor formation process to be formed, and then place on one side of the conductor
The pattern formation process of forming a fixed pattern, and then another
One side has a land shape that forms a land for a via hole.
Conducting process and conductor from above and below where there is a via hole land
To a prescribed temperature to melt the resin and connect the conductors on both sides.
A via hole forming step of continuously forming a via hole,
The step of filling the filling material in the place of the via hole, and the pattern
Patterned film and another patterned film
Laminating step of laminating a predetermined number of layers to form a laminated body,
Between the individual films by heating and pressing the laminate
And between the individual fillers and at the same time
Circuit board consisting of heating and pressurizing process for connecting conductors between layers
In the method for manufacturing a plate, the conductor forming step and the pattern
The process of forming the conductor places the conductor on one side of the polyimide film.
After the step of forming a predetermined pattern after vapor deposition to a constant thickness,
With the thermoplastic resin film underneath the polyimide
The surface of the film with the conductor pattern is the thermoplastic resin film.
The polyimide film is stacked so that it is in contact with the film.
From the top of the rum, heat it to the specified temperature and
It consists of a transfer process that transfers the conductor pattern onto the rum.
A circuit board manufacturing method is used. In addition, the thermoplastic resin
Conductor formation process to form conductors with a specified thickness on both sides of the rum
And then form a predetermined pattern on one side of the conductor
Pattern forming process, and then on the other side,
Formation process to form the land of the
Heat the conductor to the specified temperature from above and below the land area.
Melt the resin and connect the conductors on both sides to form the via hole.
A via hole forming process is performed, and then a metal electrode is formed on the via hole.
Contact the upper and lower parts of the
Welding process to weld the connection part and filling the via hole
The embedding step of filling the filling material and the pattern-formed
A certain number of layers with a pattern-formed film different from the film
A laminating step of laminating to form a laminated body, and adding the laminated body.
Individual adjacency forming the laminate by hot pressing
Heat applied to bond the films to each other through the filler.
In the method for manufacturing a circuit board, which comprises a pressure step,
The body forming step and the pattern forming step are performed using a polyimide film.
After depositing a conductor on one side of the film to a specified thickness, apply a specified pattern.
Forming the thermoplastic resin film.
There is a conductor pattern of the polyimide film below
Stack so that the surface is in contact with the thermoplastic film
Hey, heat to the specified temperature from above the polyimide film
Then, transfer the conductor pattern onto the thermoplastic resin film.
The transfer board manufacturing method including
I can do it. Further, the filler is a conductive paste
A circuit board manufacturing method may be used.

[0005]

With the above structure, when conductors are formed on both surfaces of the thermoplastic resin film and the film is heated from above and below the conductor, the film becomes liquid or close to liquid, and the upper and lower conductors can be easily contacted. Further, since the film once melted fixes the conductor, stable contact is maintained and the via hole can be easily formed. When the above-mentioned via hole formation is used for manufacturing a multilayer circuit board, each via hole becomes a blind via, and the thermoplastic resin film, or the thermoplastic resin film and the filling material also serve as an adhesive for adhering the layers to each other, and also filling. Since the material can also serve as the interlayer connecting material, a multilayer circuit board can be easily realized. In the second means, conductors are formed on both sides of the thermoplastic resin film, and the film is heated from above and below the conductor, so that the film becomes liquid or close to liquid, and the upper and lower conductors can be easily contacted. Further, when welding is performed by applying a predetermined current to the connection portion, the conductor connection can be made more stable by physical contact, and the via hole can be formed. When the above-mentioned via hole formation is used for manufacturing a multilayer substrate, each via hole becomes a blind via, and the thermoplastic resin film, or the thermoplastic resin film and the filler also serve as an adhesive for adhering the layers to each other, and also the filler. Since it can also serve as an interlayer connecting material, a multilayer circuit board can be easily realized.

[0006]

1 is a sectional view of a multilayer circuit board according to the present invention. The manufacturing method will be described below with reference to FIG. A copper foil was hot-pressed onto a thermoplastic resin film 5 such as polyethylene naphthalate, or nickel-copper was vapor-deposited by a vapor deposition method to attach the conductor 6. Although polyethylene naphthalate is used as the thermoplastic resin film 5 in this embodiment, other thermoplastic resin films such as polyphenylene sulfide, polyether imide and polyether ketone may be used. Next, the pattern 6 is formed by photolithography, etching, or the like. Next, as shown in FIG. 2, a trowel 10 heated from both sides was applied to the via hole land 7 to form a via. This time trowel 1
The temperature of 0 is 200 ° C to 250 ° C, and the applied pressure is 20
It is 0 g to 300 g. The thickness of the film 5 is 50μ
m. Next, although the via hole 9 was dented, the conductive paste 8 was filled therein as a filling material. As the paste, a low temperature curing type silver paste or a copper paste was used. On the other hand, films of different patterns formed in the same manner are laminated. Then heat press. Heat pressing at the same time as conductive <br/> paste also cured. The multi-layer circuit board of the present invention can be obtained as described above. As described above, the low temperature curing type paste is used as the conductive paste as the filler, but the same result can be obtained with the solder paste. Also, use fillers other than conductive paste
You may. For example, metal powder or the like.

Next, a second embodiment will be described.

In the first embodiment, the trowel 10 heated to form the via hole is applied to the thermoplastic resin film 5 with the conductor 6, but in this embodiment, the YAG laser beam 11 is applied as shown in FIG. The via hole land 7 is irradiated to heat the conductor 6, and then a trowel 16 made of a heat-resistant material such as metal or ebonite is applied with a pressure of 200.
When the film 5 is pressed from above and below with g to 300 g, the film 5 is melted, so that the conductor is brought into contact and the via hole 9 is formed. The subsequent steps are the same as those in the first embodiment.

Next, a third embodiment will be described.

In the first embodiment, after the via hole 9 is formed, a metal current 17 is applied to the via hole land 7 from above and below as shown in FIG.
Welding was performed by applying a predetermined current value in the range of μm and a pressing force of 100 g to 300 g. Subsequent steps produced a multilayer circuit board by the same method as in the first embodiment.

Next, a fourth embodiment will be described.

In the second embodiment, after forming the via hole 9, the metal electrode 17 is applied to the via hole land 7 from above and below as shown in FIG.
Welding was performed by applying a predetermined current value in the range of μm and a pressing force of 100 g to 300 g. Subsequent steps produced a multilayer circuit board by the same method as in the first embodiment.

[0013] In the first embodiment, the pattern of the conductor 6 has been formed by a photolithography etching, an example of forming a pattern of conductors 6 by other methods
This will be described with reference to FIG. First, nickel and copper were vapor-deposited as a conductor 6 on one surface of the polyimide film 19 in a predetermined thickness. At this time, a metal mask was used to form a predetermined pattern. Next, the thermoplastic resin film 5 such as polyethylene naphthalate is placed underneath so that the surface of the polyimide film 19 on which the conductor 6 is formed corresponds to the thermoplastic resin film 5. Next 300 ° C
Soldering iron 20 heated to ~ 450 ° C is polyimide film 1
Aim it from the surface of 9 which does not have the conductor 6, and move it slowly.
Then, the surface of the thermoplastic resin film 5 is slightly melted. Then, this acts as an adhesive, and the conductor 6 is transferred from the surface of the polyimide film having weak adhesion to the surface of the thermoplastic resin film. The circuit board pattern can be created by the above method.

Next, regarding the formation of the conductor 6, the above-mentioned trowel is used.
A method different from the heating method will be described with reference to FIG.

On one side of the polyimide film 19, the conductor 6
As a predetermined thickness, nickel and copper were vapor-deposited. At this time, a metal mask was used to form a predetermined pattern. Next, with a thermoplastic resin film 5 such as polyethylene naphthalate underneath, the polyimide film 1
The thermoplastic resin film 5 is overlaid so that the surface of the conductor 9 on which the conductor 6 is formed hits. In the above example , when the conductor is transferred, the heated iron 20 is used, but in the present embodiment, the die is 300 ° C. by the die 22 having the shape of the wiring pattern with the built-in heater 21, as shown in FIG. ~ 450 ° C
It is heated to the temperature of and the conductors are transferred at once. It is possible to form a pattern more efficiently than in the above example .

When transferring conductors , use a heated iron
Instead of the above-mentioned example , as shown in FIG. 7, by irradiating the laser light 23 from the surface of the polyimide film on which the conductor is not formed,
Heat the polyimide film. Then, where the surface of the thermoplastic resin film 5 is slightly melted, it is pressed with a trowel 27 made of a heat-resistant material to move the portion irradiated with the laser light 23 and move the trowel 27 to transfer the conductor 6. To do. In addition to the example shown in FIG. 5, it can be used for partial pattern correction in addition to the formation of the conductor pattern 6, and it becomes possible to form a fine pattern by irradiating a laser beam with a small area.

[0017]

As described above, according to the present invention, even if the plating method is not used for forming the via hole, the connection between the upper and lower conductors can be easily made only by melting the film with heat, so that the device and the process can be simplified. Become. Further, when it is used for manufacturing a multi-layered substrate, a multi-layered substrate including blind vias can be easily formed, so that high density of the substrate can be realized. Further, since the thermoplastic resin film, or the thermoplastic resin film and the filler also serves as an adhesive for sticking the layers to each other, and the filler can also serve as an interlayer connecting material, an adhesive for connecting the layers is not used, It is possible to eliminate the conventional via connection failure. In addition, the film can be melted by heat to be connected to the upper and lower conductors, and the connecting portion can be welded to further stabilize the connection. When used for manufacturing a multi-layer substrate, a substrate with higher reliability can be obtained. Since the productivity is improved and the capital investment is less than ever, it can greatly contribute to the cost reduction and the production efficiency improvement of the multilayer circuit board. Further, by further welding after forming the via hole, the connection resistance can be stabilized, and the reliability of the via hole is further improved. Regarding pattern transfer of pattern formation, unlike conventional pattern transfer, since the thermoplastic resin film acts as an adhesive, it is possible to transfer the conductor directly without using any adhesive, etc. The pattern formation process is simplified. Further, even in the case of forming a conductor pattern, the pattern can be formed in a completely dry atmosphere without a wet process such as etching, so that the pattern can be easily formed without the need for the cost of environmental measures. In addition, it can greatly contribute to cost reduction and mass productivity improvement of the multilayer circuit board.

[Brief description of drawings]

FIG. 1 is a sectional view of a circuit board according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a circuit board for explaining a method of manufacturing the circuit board according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a circuit board for explaining a circuit board manufacturing method according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a circuit board illustrating a method of manufacturing a circuit board according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a circuit board illustrating a method of manufacturing a circuit board according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a circuit board illustrating a method of manufacturing a circuit board according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view of a circuit board illustrating a method of manufacturing a circuit board according to a seventh embodiment of the present invention.

FIG. 8 is a sectional view of a conventional flexible multilayer substrate.

[Explanation of symbols]

5 Thermoplastic resin film 6 conductors 7 beer hall land 8 Conductive paste 9 Beer hall 10 heated trowel 11 YAG laser light 16 Trowels made of heat-resistant material 17 Metal electrode 19 Polyimide film 20 heated trowel 21 heater 22 mold 23 Laser light 27 Trowels made of heat-resistant material

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H05K 3/46 H05K 3/46 N (72) Inventor Manabu Tasaki 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. ( 72) Inventor Hidenobu Nishikawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-52-71677 (JP, A) JP-A-63-250192 (JP, A) JP Japanese Unexamined Patent Publication No. 4-196290 (JP, A) Japanese Unexamined Patent Publication No. 1-194385 (JP, A) Japanese Unexamined Patent Publication No. 52-8472 (JP, A) Japanese Unexamined Patent Publication No. 36591 (JP, A) Japanese Unexamined Patent Publication No. 58-97895 (JP , A) JP-B-55-5822 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H05K 1/11 H05K 3/40 H05K 3/46

Claims (4)

(57) [Claims] 1. A conductor is provided on both sides of a thermoplastic resin film.
Conductor formed to a constant thicknessForming processAnd then a piece of that conductor
Form a predetermined pattern on one sidePattern formation process
And then, the land of the via hole is formed on the other surface.
DoLand formation processAnd a part of the beer hall land
Heat the conductor from above and below to the specified temperature to melt the resin,
Connect vias on surface to form via holesBeer hall
Forming processAnd the step of filling the filling material in the via hole
And a pattern shape different from the film on which the pattern is formed
Laminate a predetermined number of layers to form a laminateproduct
Layer processBy heating and pressing the laminate,Individual
Bond between the films and the individual fillers at the same time
And a heating and pressurizing step of connecting conductors between the layers by the filler.
Method of manufacturing circuit board comprisingAt The conductor forming step and the pattern forming step are
After depositing a conductor to the specified thickness on one side of the mid film,
The step of forming a pattern, and then the thermoplastic resin film
Conductor pattern of the polyimide film with rum down
So that the side with the contact with the thermoplastic resin film
Stacked, above the polyimide film at a predetermined temperature
Heat to a conductor pattern on the thermoplastic resin film
A method of manufacturing a circuit board, which comprises a transfer step of transferring 2. A conductor is provided on both sides of the thermoplastic resin film.
Form to a fixed thicknessConductor formation processAnd then a piece of that conductor
Form a predetermined pattern on one sidePattern formation process
And then, the land of the via hole is formed on the other surface.
DoLand formation processAnd a part of the beer hall land
Heat the conductor from above and below to the specified temperature to melt the resin,
Connect vias on surface to form via holesBeer hall
Forming processNext, the metal electrode is placed on the via hole from above
Weld the conductor connection parts by bringing them into contact with each other and passing a specified current.
Welding processAnd fill the via hole with filling materialEmbedding
Only processAnd a pattern different from the film on which the pattern is formed.
Form a laminated body by laminating a predetermined number of layers that have already been formed.
CompleteLaminating processAnd heating and pressurizing the laminate.
The space between the individual adjacent films that make up the laminate is
Join each other via fillerHeating and pressing processTimes consisting of
Road board manufacturing methodAt The conductor forming step and the pattern forming step are
After depositing a conductor to the specified thickness on one side of the mid film,
The step of forming a pattern, and then the thermoplastic resin film
Conductor pattern of the polyimide film with rum down
So that the side with the contact with the thermoplastic resin film
Stacked, above the polyimide film at a predetermined temperature
Heat to a conductor pattern on the thermoplastic resin film
A method of manufacturing a circuit board, which comprises a transfer step of transferring 3. The method for manufacturing a circuit board according to claim 1, wherein the filler is a conductive paste. 4. A circuit board manufactured by the method of manufacturing a circuit board according to claim 1, 2, or 3 .