JPH05343849A - Manufacture of multilayer electronic component mounting substrate - Google Patents

Abstract

PURPOSE:To avoid damage to an inner layer conductor circuit exposed in an electronic component mounting part by a method wherein a plating catalyst is applied to the whole surface of a multilayer board, an electronic component mounting board, and through holes; a dry film is affixed to the whole surface of the multilayer board; the parts only opposite to the through holes are removed by development step; and then the through holes are internally metal plated. CONSTITUTION:A plating catalyst is applied to the whole surface of a multilayer board, an electronic component mounting part 95 and through holes 97; a dry film 1 is affixed to the whole surface of the multilayer board; the parts only opposite to the through holes 97 in the dry film 1 are removed by development step; and then the through holes 97 are internally metal plated. At this time, the dry film 1 affixed to the upper part 71 of the multilayer board is covering the electronic component mounting part 95, the aperture part thereof and the copper foil layer 710 of the second substrate 7 so that the inner layer conductor circuit 911 in the electronic part mounting part 95 may not be metal plated. Accordingly, the removing step of the metal plating in the conventional electronic component mounting part 95 can be eliminated thereby enabling the damage to the inner layer conductor circuit 911 to be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer electronic component mounting substrate which does not damage an inner layer conductor circuit in an electronic component mounting portion.

[0002]

2. Description of the Related Art Conventionally, as a method for manufacturing a multilayer electronic component mounting substrate having an electronic component mounting portion on the substrate, there is one shown in FIGS. 8 to 10 (Japanese Patent Laid-Open No. 61-75596). That is, as shown in FIG. 10, this method comprises: a first substrate 9 provided with an inner layer conductor circuit 911 electrically connected to an electronic component; and a second substrate 7 joined thereto via an adhesive layer 5. , A method of manufacturing a multilayer electronic component mounting substrate having an electronic component mounting recess 950 provided above the first substrate 9.

In this method, first, as shown in FIG. 8A, a first substrate having an electronic component mounting portion 951 having a nickel / gold plating layer formed on an upper portion 91 of the substrate and an inner layer conductor circuit 911. Prepare 9. Further, the second substrate 7 having the opening 75 larger than the electronic component mounting portion 951 and the outer layer conductor circuit 711 having the same plating layer as the above on the upper portion 71, and the same plane shape as the opening 75 And the adhesive layer 5 having the opening 55.

Next, as shown in FIG. 8B, the second substrate 7 is laminated on the first substrate 9 with the adhesive layer 5 interposed therebetween, and these are joined by thermocompression bonding to form a multilayer board. To do. Then, as shown in FIG. 9A, through holes 97 are formed in the multilayer plate, and further, the entire surface of the multilayer plate and the through holes 97 are formed.
A metal (copper) plating 11 is applied to.

Then, as shown in FIG. 9B, the outer conductor circuit 9 is formed on the lower portion 99 of the first substrate 9 by etching.
91, and the outer layer conductor circuit 7 on the upper part 71 of the second substrate 7.
11 is formed. As a result, as shown in FIG. 10, a recess 950 surrounded by the opening 75 of the second substrate 7 is formed on the electronic component mounting portion 951. Also, the through hole 9
The lead pin 6 is inserted into 7.

[0006]

However, as shown in FIG. 9B, in the step of forming the outer layer conductor circuits 991 and 711, the inner layer conductor circuit 911 exposed in the electronic component mounting portion 951 may be contaminated. is there. That is, when the outer layer conductor circuits 991 and 711 are formed, as described above, first, the through hole 97 and the entire surface of the substrate are once copper-plated 11 and then the electronic component mounting portion 951 and the initial inner layer conductor circuit 911 are formed. The copper plating 11 (FIG. 9a) on the top of the substrate has been removed by etching.

As a result, the surface of the inner-layer conductor circuit 911 may be contaminated, and the electrical connection may be deteriorated.
In view of the above problems, the present invention aims to provide a method for manufacturing a multilayer electronic component mounting substrate that does not damage the inner layer conductor circuit exposed in the electronic component mounting portion.

[0008]

According to the present invention, a first substrate on which an inner layer conductor circuit is formed and at least one second substrate having an opening located above an electronic component mounting portion are attached via an adhesive layer. A laminating step of forming a multi-layer board in combination, a through-hole forming step of providing a through-hole at a predetermined position of the multi-layer board, a film adhering step of adhering a film-like mask so as to cover the opening. An outer layer circuit forming step of forming an outer layer circuit is provided, which is a method for manufacturing a substrate for mounting a multilayer electronic component.

Further, as a manufacturing method for carrying out the above manufacturing method, there is the following method. That is, a laminating step of forming a multilayer board by bonding a first substrate on which an inner layer conductor circuit is formed and at least one second substrate having an opening above an electronic component mounting portion via an adhesive layer to form a multilayer board. , Step B of providing a through hole at a predetermined position of the multilayer board, and the entire surface of the multilayer board,
The electronic component mounting portion and the step C of applying a plating catalyst to the through holes are performed.

After that, the step D of attaching a dry film to the entire surface of the multilayer board, and exposing the dry film and developing and removing the part of the dry film facing the through hole, leaving the other part of the dry film. E process to put,
The F step of performing metal plating in the through hole, the G step of removing the dry film, and the H step of removing the plating catalyst on the surface of the multilayer board by soft etching are performed.

What is most noticeable in the above manufacturing method is the step C in which a plating catalyst is applied to the entire surface of the multilayer board, the electronic component mounting portion, and the through holes, and the dry film is adhered to the entire surface of the multilayer board D. The steps of exposing the dry film and developing and removing the dry film in the portion facing the through hole, leaving the dry film in the other portion, and the step of applying metal plating in the through hole. It is in the G step of removing the dry film.

The first substrate has an electronic component mounting portion on an upper portion thereof and an inner layer conductor circuit provided on a peripheral portion thereof.
The second substrate has an opening larger than the electronic component mounting portion. The electronic component mounting portion has a concave shape, a flat shape, a through hole, or the like.

The multilayer board comprises a first substrate and a second substrate laminated on the first substrate. An intermediate substrate may be provided between the first substrate and the second substrate. The intermediate substrate has an opening larger than the electronic component mounting portion and smaller than the outer diameter of the opening of the first substrate, and an inner layer conductor circuit formed in the peripheral portion of the opening. The opening of the intermediate substrate has a larger outer diameter as it goes upward.

That is, according to the present invention, the second substrate is provided above the first substrate having the electronic component mounting portion, and one or a plurality of the intermediate substrates may be provided between the two substrates. it can. A copper foil layer is previously provided on the upper part of the second substrate and the upper and lower parts of the first substrate.

In the photosensitive dry film, even in the step of applying the metal plating to the through hole (step F), the electronic component mounting portion and its opening, and the copper foil layer provided on the second substrate are formed. To cover. Dry film has excellent resistance to chemical copper plating solutions and strong alkalis. The adhesive layer is made of sheet-like prepreg and is interposed between the substrates. The prepreg is preferably made of the same material as the substrate.

As the first and second substrates and the intermediate substrate, a copper clad laminate of epoxy, triazine, polyimide resin or the like is used. In the electronic component mounting area, improved moisture resistance,
It is preferable to form a metal plating film in order to improve heat dissipation. The inner and outer conductor circuit surfaces are usually plated with nickel and gold. The through hole is a hole for attaching an external lead terminal such as a lead pin.

After the through holes are plated with metal, soft etching is performed (step H). The soft etching is to remove the plating catalyst remaining on the surface of the insulating substrate. Sulfuric acid or the like is used as the soft etching solution used for the soft etching.

The outer conductor circuit is formed after the through hole is plated with metal. As a method of forming the outer layer conductor circuit, a dry film covers a portion forming the outer layer conductor circuit, and then a resist film covers a portion forming the outer layer conductor circuit, and the dry film is removed.
Then, the copper foil layer in a portion where the outer layer conductor circuit is not formed is removed by etching, and then the resist film is removed (I to
M to N steps). As the resist film, there is a photosensitive dry film or the like, which does not dissolve in the etching solution. Examples of the etching liquid include copper chloride and tetraammine copper chloride, which dissolve the copper foil layer.

[0019]

In the method of manufacturing a substrate for mounting a multilayer electronic component of the present invention, a film-like mask is attached so as to cover the opening located above the electronic component mounting portion. Therefore, metal plating is not applied to the inner conductor circuit in the electronic component mounting portion. Further, in the manufacturing method for carrying out the above-mentioned manufacturing method, a plating catalyst is applied to the entire surface of the multilayer board, the electronic component mounting portion, and the through holes (step C), and a dry film as a film-shaped mask is applied to the multilayer board. The entire surface is attached (step D), only the portion facing the through hole is developed and removed (step E), and then the through hole is metal-plated (step F).

In the step D, the dry film attached to the upper portion of the multilayer board covers the electronic component mounting portion and its opening, and the copper foil layer of the second substrate. Therefore, metal plating is not applied to the inner conductor circuit in the electronic component mounting portion. Therefore, the outer conductor circuit can be formed without damaging the surface of the insulating substrate and the inner conductor circuit. As described above, according to the present invention, it is possible to provide a method for manufacturing a multilayer electronic component mounting substrate that does not damage the inner layer conductor circuit exposed in the electronic component mounting portion.

[0021]

EXAMPLE 1 A method for manufacturing a substrate for mounting a multilayer electronic component according to an example of the present invention will be described with reference to FIGS. The multilayer electronic component mounting board manufactured by the manufacturing method of this example is
As shown in FIG. 5 (n), it has a first substrate 9 and a second substrate 7.

The upper portion 91 of the first substrate 9 is provided with a concave electronic component mounting portion 95 and an inner layer conductor circuit 911 for electrically connecting with the electronic component. The electronic component mounting portion 95 is covered with a metal plating 951. Further, a heat dissipation layer 996 and an outer layer conductor circuit 991 are provided on the lower portion 99 of the first substrate 9.

The second substrate 7 has an opening 75 larger than the outer diameter of the electronic component mounting portion 95, and an upper layer 71 has an outer layer conductor circuit 711 including a land of the through hole 97 and a connection circuit. Is forming. A second substrate 7 is laminated on the first substrate 9 via an adhesive layer 5 made of prepreg, and these form a multilayer board. Through holes 97 are formed at predetermined positions of the multilayer board. The through hole 97 is covered with the metal plating 3.

Next, steps A to N in the method of manufacturing the above-mentioned substrate for mounting a multilayer electronic component will be described. First, in the step A, as shown in FIG. 1A1, the first substrate 9, the second substrate 7, and the adhesive layer 5 are prepared. The first substrate 9 has an electronic component mounting portion 95 having an upper portion 91 covered with a metal plating 951 and an inner layer conductor circuit 911 around the opening. The lower part 99 is a copper foil layer 99.
Has 0.

The upper portion 71 of the second substrate 7 is a copper foil layer 71.
It has an opening 75 which is covered with 0 and is larger than the outer diameter of the electronic component mounting portion 95. In the lower portion 79 of the second substrate 7,
The adhesive layer 5 made of prepreg is attached. The adhesive layer 5 has an opening 55 having the same shape as the opening 75 of the second substrate.
Have. Next, as shown in FIG. 1 (a2), the second substrate 7 is laminated on the first substrate 9 via the adhesive layer 5, and these are bonded by thermocompression bonding to obtain a multilayer board.

In step B, as shown in FIG. 1B, a through hole 97 is formed at a predetermined position of the multilayer board. In step C, as shown in FIG. 2C, the multilayer board is immersed in the plating catalyst solution. As a result, the entire surface of the multilayer board, that is, the upper portion 71, the lower portion 99, and the electronic component mounting portion 9 of the multilayer board.
5, opening 7 provided above the electronic component mounting portion 95
5, all of the through holes 97 are covered with the plating catalyst 2. Valladium chloride is used as the plating catalyst liquid.

In step D, as shown in FIG. 2D, the dry film 1 is attached to the entire surface of the multilayer board.
In the step E, as shown in FIG. 2E, the dry film 1 is exposed and holes 17 are formed at the portions corresponding to the through holes 97.
To provide. Then, the dry film 1 in the part facing the through hole 97 is developed and removed, and the other part is dry film 1
Leave.

In step F, as shown in FIG. 3 (f), the multilayer board is immersed in a metal plating solution. As a result, the through hole 97 is covered with the metal plating 3. Copper plating is used as the metal plating solution. In the G step, the dry film is removed from the multilayer board as shown in FIG. In the H step, as shown in FIG.
The plating catalyst on the surface of the multilayer board is removed by soft etching.

In step I, as shown in FIG. 4 (i), the dry film 1 is attached again to the entire surface of the multilayer board. In the J process, as shown in FIG. 4 (j), the portion where the dry film 1 is exposed to form the outer conductor circuit,
The dry film in the portion facing the opening 75 of the electronic component mounting portion 95 and the through hole 97 is removed by development, and the dry film 1 is left in the other portions.

In step K, as shown in FIG. 4 (k), the multi-layer plate is immersed in the electrodeposition solution, and the electrodeposition solution is energized. As a result, the portion where the resist film 4 forms the outer conductor circuit, the opening 75 of the electronic component mounting portion 95, and the through hole 97.
Is formed in the portion facing the.

In step L, the dry film is removed as shown in FIG. In the M step, as shown in FIG. 5 (m), a portion of the copper foil layer where the outer layer conductor circuit is not formed is removed by etching. In the N step, as shown in FIG. 5N, the resist film is removed and the outer conductor circuits 711, 991 and the heat dissipation layer 996 are formed on the surface of the multilayer board.

In the method of manufacturing the multilayer electronic component mounting substrate of this example, the entire surface of the multilayer plate, the electronic component mounting portion 95,
Then, the plating catalyst 2 is applied to the through holes 97 (step C), the dry film 1 is attached to the entire surface of the multilayer board (step D), and only the portion of the dry film facing the through holes 97 is removed by development (step E). ), And then the metal plating 3 is applied to the through holes 97 (step F).

In the step D, the dry film 1 attached to the upper portion 71 of the multilayer board is attached to the electronic component mounting portion 9
5 and the opening 75 thereof, and the copper foil layer 710 of the second substrate 7 are covered. Therefore, the inner layer conductor circuit 911 in the electronic component mounting portion 95 is not metal-plated.
Therefore, the step of removing the metal plating in the electronic component mounting portion 95 in the conventional example is unnecessary. Therefore, the inner layer conductor circuit 911 in the electronic component mounting portion 95 is not damaged.

Further, in this example, the portion forming the outer layer conductor circuit, the through hole 97, the electronic component mounting portion 95, and the inner layer conductor circuit 911 exposed in the electronic component mounting portion 95 are covered with the resist film 4. Then, the copper foil layers 710 and 990 where the outer layer conductor circuit is not formed are removed by etching (step M). The resist film 4 is not dissolved by etching. Therefore, the outer layer conductor circuits 711 and 991 can be formed without damaging the surface of the multilayer board and the inner layer conductor circuits 911 exposed in the electronic component mounting portion 95.

Example 2 The electronic component mounting substrate manufactured by the manufacturing method of this example has a planar recess 952 as shown in FIG. Others are the same as those of the electronic component mounting board in the first embodiment. The manufacturing method of the electronic component mounting substrate of this example is as follows.
This is the same as the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained.

Example 3 An electronic component mounting substrate manufactured by the manufacturing method of this example is provided with an electronic component mounting portion 953 formed of a through hole as shown in FIG. In this electronic component mounting portion 953,
For example, a metal heat dissipation plate is provided, and electronic parts are mounted in the recess formed on the metal heat dissipation plate. Others are the same as those of the electronic component mounting board in the first embodiment. The method of manufacturing the electronic component mounting substrate of this example is the same as that of the first embodiment. Also in this example, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing process of a multilayer electronic component mounting substrate according to a first embodiment.

FIG. 2 is an explanatory view of the manufacturing process following FIG.

3 is an explanatory view of the manufacturing process following FIG. 2. FIG.

FIG. 4 is an explanatory view of the manufacturing process following FIG.

FIG. 5 is an explanatory view of the manufacturing process following FIG.

FIG. 6 is an explanatory view of the manufacturing process of the multilayer electronic component mounting substrate according to the second embodiment.

FIG. 7 is an explanatory view of a manufacturing process of the multilayer electronic component mounting substrate according to the third embodiment.

FIG. 8 is an explanatory view of a manufacturing process of a conventional multilayer electronic component mounting substrate.

FIG. 9 is an explanatory view of the manufacturing process following FIG.

FIG. 10 is an explanatory view of the manufacturing process subsequent to FIG. 9;

[Explanation of symbols]

 1. ． ． Dry film, 2. ． ． Plating catalyst, 3. ． ． Metal plating, 4. ． ． Resist film, 5 ,. ． ． Adhesive layer, 55, 75 ,. ． ． Opening, 7 ,. ． ． Second substrate, 711, 991. ． ． Outer layer conductor circuit, 71, 91. ． ． Top, 9. ． ． First substrate, 911. ． ． Inner layer conductor circuit 95, 952, 953. ． ． Electronic component mounting part, 79, 99. ． ． beneath,

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H05K 3/28 G 7511-4E 3/42 A 7511-4E

Claims (2)

[Claims] 1. A first substrate on which an inner layer conductor circuit is formed,
Laminating step of forming a multilayer board by bonding at least one second substrate having an opening located above the electronic component mounting portion via an adhesive layer, and providing a through hole at a predetermined position of the multilayer board. For mounting a multilayer electronic component, comprising: a through hole forming step, a film attaching step of attaching a film mask to cover the opening, and an outer layer circuit forming step of forming an outer layer circuit. Substrate manufacturing method. 2. A first substrate having an inner conductor circuit formed thereon,
Laminating step of forming a multilayer board by bonding at least one second substrate having an opening located above the electronic component mounting portion via an adhesive layer, and providing a through hole at a predetermined position of the multilayer board. Step B, step C of applying a plating catalyst to the entire surface of the multilayer board, electronic component mounting area, and through holes, step D of attaching a dry film to the entire surface of the multilayer board, and exposing and penetrating the dry film. The step E is to develop and remove the dry film in the part facing the hole, and leave the dry film in the other part, the step F to perform metal plating in the through hole, the step G to remove the dry film, A method for manufacturing a substrate for mounting a multilayer electronic component, comprising the step H of removing the plating catalyst on the surface of the multilayer plate by soft etching.