JPH06152143A - Manufacture of electronic part mounting board - Google Patents

Abstract

PURPOSE:To provide a means for manufacturing an electronic parts mounting board wherein metal plating can be done within an opening hole, there is no short circuit between a bonding wire and a ring-like plating, and further, a fine pattern is easily formed. CONSTITUTION:In manufacturing an electronic parts mounting board that contains an opening hole 99 for forming a recessed section for mounting an electronic parts, the opening hole 99 that contains a tapered inner wall 991, gradually becoming wider in the direction from the front side of a circuit board 9 toward the rear side of it, is formed. The entire surface of the circuit board 9 including the surface of the opening hole 99 is coated with a metal plating 5 and an electro-deposition film 6. For the opening hole 99 and its vicinity to be irradiated with light 79 for exposure, a mask film 7 is placed, and the light is poured for development, and then the electro-deposition film 6 around the opening hole 99 is removed. Further, the metal plating 5 around the opening hole 99 is removed by etching, then remaining electro-deposition film 6 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electronic component mounting board.

[0002]

2. Description of the Related Art Conventionally, as an electronic component mounting board, for example, as shown in FIG. 7, a circuit board 9 having inner layer circuits 51 and 52, an opening hole 99 provided in the circuit board 9, and an opening hole 99 are provided. There is a heat sink 8 adhered so as to cover one end thereof, and an electronic component mounting recess 900 formed by the heat sink 8 and the opening hole 99.

The inner wall 999 of the opening hole 99 is provided with a metal plating 5 for preventing moisture intrusion, and the opening hole 99 is also formed.
A ring-shaped plating 59 is formed around the area. On the other hand, the heat sink 8 is adhesively fixed to the periphery of the opening hole 99 on the back side of the circuit board 9 via an adhesive sheet 65. The circuit board 9 includes insulating boards 91, 92, 93.
Are formed by stacking. Insulating substrate 91,
The inner layer circuits 51 and 52 are formed on 92.

An outer layer circuit 50 is formed on the front surface of the circuit board 9. Further, the back side surface of the circuit board 9 is covered with a metal plating 5 for preventing moisture. The electronic component 3 is mounted in the electronic component mounting recess 900, and the outer layer circuit 5 on the circuit board 9 is bonded by the bonding wire 30.
It is electrically connected to 0.

Next, a method of manufacturing the electronic component mounting board will be described. In the above manufacturing method, recently, there is a pattern forming method using an electrodeposition film. The electrodeposition film method is an excellent method for forming fine patterns. Below, this method is shown first.

That is, in the J process shown in FIG.
The insulating substrates 91, 92, 93 are laminated in order from the bottom to manufacture the circuit board 9. Inner layer circuits 51 and 52 are formed on the insulating substrates 91 and 92, respectively. Next, FIG.
In step K shown in (K), the opening hole 99 is formed in the circuit board 9. Next, in the L step shown in FIG. 8L, the circuit board 9 including the inner wall 999 of the opening hole 99 is formed.
Metal plating 5 is applied to the entire surface of.

Next, in the M step shown in FIG.
An electrodeposition film 6 is formed on the entire surface of the metal plating 5. Next, in the N step shown in FIG. 9N, the mask film 7 having the pattern 70 having the same shape as the outer layer circuit and the ring-shaped plating is placed on the front surface of the circuit board 9. And
Ultraviolet rays 79 are irradiated from above the mask film 7 to expose the electrodeposition film 6.

Next, in the step O shown in FIG. 10 (O), the mask film is removed and the exposed portion of the electrodeposition film 6 is removed by development. Next, FIG.
In the step P shown in (P), the metal plating 5 in the portion not covered with the electrodeposition film 6 is removed by etching. Next, in the step Q shown in FIG. 10 (Q), the remaining electrodeposited film 6 is removed.

Next, in the R step shown in FIG. 10 (R), the heat sink 8 is bonded via the adhesive sheet 65 so as to cover the opening hole 99 on the back side surface of the circuit board 9. According to the electrodeposition film method, as shown in FIGS. 7 and 11, the metal plating 5 is formed on the wall surface 999 of the opening hole 99, and the ring-shaped plating 59 remains on the front surface side around the opening hole 99. ing. The reason for forming the ring-shaped plating 59 is as follows.

That is, if the positional relationship between the mask film 7 and the circuit board 9 is deviated, the light irradiation position is deviated, and the inner wall 999 of the opening hole 99 is also irradiated with light, and the electrodeposition film 6 on the surface is exposed. This is because the metal plating 5 on the surface of the inner wall 999 of the opening hole 99 is removed in the developing and etching processes. Therefore, there is no choice but to form ring-shaped plating.

[0011]

However, the ring-shaped plating 59 may short-circuit with the bonding wire 30. Therefore, as shown in FIG. 12, it is considered that the ring-shaped plating is not formed around the opening hole 99 on the front surface. For that purpose, in the above N process, as shown in FIG.
And a mask film 7 in which the periphery of the mask film 7 is transparent
Can be used (compare with FIG. 9).

However, in this case, the opening hole 9 is not exposed when the light is irradiated.
The electrodeposition film 6 on the surface of the inner wall 999 of 9 is also exposed. Therefore, the metal plating 5 on the surface of the inner wall 999 is also removed in the subsequent development and etching steps. Therefore, as shown in FIG. 14, the metal plating non-adhesive portion 990 is formed on the inner wall 999. As a result, moisture may enter the opening 99 from the metal plating non-adhesive portion 990. Further, when using the electronic component mounting board on which the electronic component is mounted, it may not be possible to reduce the inductance.

In view of the above problems, a method using the solder peeling method is considered. The solder peeling method will be described below with reference to FIGS. First, as in the case of the above electrodeposition film method, J shown in FIGS. 8 (J) to 8 (L) above is used.
Process-L process are performed. Next, in step S shown in FIG. 15 (S), the photosensitive dry films 60 and 61 are placed on the front and back surfaces of the circuit board 9.

Next, in the step T shown in FIG. 15 (T), the opening 99 is formed on the photosensitive dry film 60.
The mask film 7 having a pattern 70 having the same shape as that of the outer layer circuit and the opening hole 99 and having a transparent periphery is placed. Then, ultraviolet rays 79 are irradiated from above the mask film 7 to expose the photosensitive dry film 60 located below the portion other than the pattern 70.

Next, in step U shown in FIG. 16 (U), the mask film is removed, and the unexposed portions of the photosensitive dry films 60 and 61 are removed by development. Next, in a step V shown in FIG. 16 (V), solder plating 62 is applied to the surface of the metal plating 5 not covered with the photosensitive dry film 60. Next, in the step W shown in FIG. 16 (W), the remaining photosensitive dry film 60 is removed.

Next, in step X shown in FIG. 17 (X), the metal plating 5 in the portion not covered with the solder plating 62 is removed by etching. Next, Fig. 1
In the Y step shown in FIG. 7 (Y), the remaining solder plating 62 is removed. Thereafter, as shown in FIG. 12, the heat sink 8 is adhered to the back side surface of the circuit board 9 as in the R step of the electrodeposition film method. As a result, the opening hole 99 on the front side
An electronic component mounting substrate is obtained which does not have the ring-shaped plating 59 (FIGS. 7 and 11) around the substrate.

However, the solder stripping method has many manufacturing steps and requires a long time for manufacturing. Further, it is difficult to obtain a clear wiring pattern, which is not suitable for forming a fine pattern. In view of the above problems, the present invention provides a method for manufacturing a substrate for mounting electronic components, which can form a metal plating on the inner wall of the opening hole, has no short circuit between the bonding wire and the ring-shaped plating, and can easily form a fine pattern. Is what you are trying to do.

[0018]

According to the present invention, a circuit board is prepared in a method of manufacturing an electronic part mounting board having a circuit board and an opening hole for forming an electronic part mounting recess provided in the circuit board. A step, B step of forming an opening hole having a tapered inner wall that expands from the front side surface to the back side surface of the circuit board, and the entire surface of the circuit board including the surface of the opening hole is plated with metal. Step C for coating, Step D for coating the surface of the metal plating with an electrodeposition film, placing an exposure mask film for forming a wiring pattern on the front surface of the circuit board, and from the top of the mask film E step of irradiating light, F step of removing the mask film on the circuit board and developing the circuit board to remove the electrodeposition film around the opening hole, and the front surface of the circuit board by etching the circuit board And G step of removing the metal plating around definitive opening hole, in the manufacturing method of the electronic component mounting board, characterized in that the more the H step of removing the remaining electrodeposited film from the circuit board.

What is most noticeable in the present invention is B
In the step, an opening hole having a tapered inner wall that expands from the front side surface direction of the circuit board toward the back side surface is formed in the circuit board. The circuit board is composed of one or a plurality of insulating boards. Also, inside the circuit board,
Inner layer circuits and through holes can be formed.

An outer layer circuit can be formed on one or both of the front side surface and the back side surface of the electronic component mounting board. A heat sink is adhered around the opening of the circuit board. When adhering the heat sink to the circuit board, an adhesive sheet or the like is preferably used.

[0021]

In the present invention, the opening hole has a tapered inner wall that widens from the front side surface to the back side surface.
Therefore, in the E step of exposing, the light is blocked by the upper end of the expanded tapered inner wall, and the entire tapered inner wall is not irradiated with light (see FIG. 4 (Example)). Therefore,
Even if the development and etching are performed, the metal plating can be formed on the entire tapered inner wall.

Further, since the mask film is transparent in the opening hole of the circuit board and the portion located around the opening hole,
At the time of light irradiation, the electrodeposition film around the opening is exposed. Therefore, the metal plating around the opening hole can be removed.
Therefore, ring-shaped plating is not formed unlike the conventional case. Therefore, according to the present invention, the metal plating can be formed in the opening hole without forming the ring-shaped plating.

Therefore, the bonding wire that electrically connects the electronic component and the outer layer circuit does not short-circuit with the ring-shaped plating. Therefore, according to the present invention, it is possible to provide a method for manufacturing a substrate for mounting electronic parts in which a metal plating can be formed in the opening, a bonding wire and a ring-shaped plating are not short-circuited, and a fine pattern can be easily formed. it can.

[0024]

【Example】

Example 1 An example according to the present invention will be described with reference to FIGS. The electronic component mounting board manufactured by this example is
As shown in FIGS. 1 and 2, a circuit board 9 having inner layer circuits 51 and 52, an opening hole 99 provided in the circuit board 9, and a heat sink 8 bonded so as to cover one end of the opening hole 99, It has an electronic component mounting recess 900 formed by the heat sink 8 and the opening 99.

The entire inner wall of the opening hole 99 is covered with the metal plating 5. The heat sink 8 is adhesively fixed to the circuit board 9 through the adhesive sheet 65 in the opening 99 on the back side of the circuit board 9. The circuit board 9 is formed by stacking insulating boards 91, 92, 93. Inner layer circuits 51 and 52 are formed on the insulating substrates 91 and 92.

An outer layer circuit 50 is formed on the front surface of the circuit board 9. In the circuit board 9, the electronic component mounting recess 900 and the back side surface thereof are covered with a metal plating 5 to prevent moisture. Further, on the front side, the ring-shaped plating 59 shown in the above-mentioned conventional example is provided around the opening hole 99.
(FIGS. 7 and 11) are not formed. Others are the same as the conventional example.

Next, a method of manufacturing the electronic component mounting board will be described. First, in the step A shown in FIG. 3A, the insulating substrates 91, 92, 93 are prepared, and these are stacked in order from the bottom to manufacture the circuit board 9. Inner layer circuits 51 and 52 are formed on the insulating substrates 91 and 92, respectively. Next, in a step B shown in FIG. 3B, an opening hole 99 having a tapered inner wall 991 that expands from the front side surface direction of the circuit board 9 toward the back side surface is formed in the circuit board 9.

Next, in the step C shown in FIG.
Metal plating 5 is applied to the entire surface of the circuit board 9 including the tapered inner wall 991 of the opening hole 99. Next, FIG.
In step D shown in (D), an electrodeposition film 6 is formed on the entire surface of the metal plating 5.

Next, in the step E shown in FIG.
The mask film 7 is placed on the front side surface. The mask film 7 is provided with a pattern 70 for forming an outer layer circuit. Further, the mask film 7 is formed so that the position where the outer layer circuit of the circuit board 9 is formed is not irradiated with light.

Next, ultraviolet rays 7 are applied from above the mask film 7.
9 is irradiated with light to expose the electrodeposition film 6. Next, FIG. 4 (F)
In the step F shown in (1), the mask film is removed and the circuit board 9 is developed to remove the electrodeposited film 6 around the opening hole 99 which is irradiated with light. Further, the electrodeposited film 6 irradiated with light at the position where the outer layer circuit is not formed is also removed.

Next, in the G step shown in FIG.
By etching the circuit board 9, the opening hole 9
The metal plating 5 around 9 and the metal plating 5 in the portion where the outer layer circuit is not formed are removed. Next, in step H shown in FIG. 5H, the remaining electrodeposition film is removed from the circuit board 9. Next, in a step I shown in FIG. 5I, the heat sink 8 is adhered to the vicinity of the opening hole 99 on the back side surface of the circuit board 9 via the adhesive sheet 65. As a result, the electronic component mounting board shown in FIGS. 1 and 2 is obtained.

Next, the function and effect of this example will be described. In this example, as shown in FIG. 3, the opening hole 99 has a tapered inner wall 991 that widens from the front side surface to the back side surface. Therefore, as shown in FIG.
In the process, the ultraviolet ray 79 is blocked by the upper end of the expanded tapered inner wall 991 and does not irradiate the entire tapered inner wall 991. Therefore, even if the developing and etching are carried out, the metal plating 5 can be left and formed on the entire opening 99.

Further, since the mask film 7 is transparent in the opening hole 99 of the circuit board 9 and the portion located around the opening hole 99, the electrodeposition film 6 around the opening hole 99 is exposed during light irradiation. Therefore, the metal plating 5 around the opening hole 99 can be removed. Therefore, ring-shaped plating is not formed unlike the conventional case.

Therefore, according to this embodiment, the metal plating 5 can be left on the tapered inner wall 991 of the opening hole 99 without forming the ring-shaped plating. Therefore, the bonding wire 30 that electrically connects the electronic component 3 and the outer layer circuit 50 does not short-circuit with the ring-shaped plating (see FIG. 11).

Example 2 An electronic component mounting board manufactured by this example is, as shown in FIG. 6, a circuit board 9 composed of insulating boards 94 to 96,
Opening holes 97, 98 provided in the circuit board 9 and the opening holes 9
8 has a heat sink 8 adhered so as to cover one end thereof. The opening holes 97 and 98 are tapered inner walls 97 that widen from the front side surface direction of the circuit board 9 toward the back side surface.
1,981. An enlarged portion 982 for burying the heat sink 8 is formed below the opening hole 98.
The opening holes 97 and 98 and the heat sink 8 form an electronic component mounting recess 900.

Inner layer circuits 54 and 55 are formed on the front side surfaces of the insulating substrates 94 and 95. The insulating substrate 94
The heat sink 8 is adhered to the back surface side of the via a bonding sheet 65. The insulating substrates 95 and 96 and the insulating substrate 94
And are bonded by an adhesive sheet 65. Circuit board 9
An outer layer circuit 50 is formed on the front side surface of the. The back side surface is covered with metal plating 5.

A method of manufacturing the electronic component mounting board will be described. First, steps A to H are performed on the insulating substrates 95 and 96 as in the first embodiment. The insulating substrate 96
No metal plating is formed on the back side of the. Further, regarding the insulating substrate 94, in the process B, the tapered inner wall 98 is formed.
1 and the opening hole 98 including the enlarged portion 982 are formed. Thereafter, the steps C to I are performed in the same manner as in Example 1.

Thereafter, insulating substrates 95 and 96 are laminated on the front surface of the insulating substrate 94 with an adhesive sheet 65 interposed therebetween. As a result, the electronic component mounting board shown in FIG. 6 is obtained.
Also in this example, since the tapered inner walls 971 and 981 are formed in the opening holes 97 and 98, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an electronic component mounting board according to a first embodiment.

FIG. 2 is a plan view of the electronic component mounting board according to the first embodiment.

FIG. 3 is an explanatory view of the manufacturing process of the electronic component mounting board according to the first embodiment.

FIG. 4 is an explanatory view of the manufacturing process subsequent to FIG.

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

FIG. 6 is a cross-sectional view of an electronic component mounting board according to a second embodiment.

FIG. 7 is a cross-sectional view of a conventional electronic component mounting substrate.

FIG. 8 is an explanatory view of a manufacturing process of an electronic component mounting substrate according to a conventional example by an electrodeposition film method.

9 is an explanatory view of the manufacturing process following FIG. 8. FIG.

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

FIG. 11 is a plan view of a conventional electronic component mounting board.

FIG. 12 is a cross-sectional view of an electronic component mounting board to be obtained in another conventional example.

FIG. 13 is an explanatory view of a manufacturing process of an electronic component mounting substrate according to another conventional example by another electrodeposition film method.

FIG. 14 is an explanatory view showing a problem of a method of manufacturing an electronic component mounting board according to another conventional example.

FIG. 15 is an explanatory view of a manufacturing process by a solder peeling method of an electronic component mounting board according to still another conventional example.

FIG. 16 is an explanatory view of the manufacturing process following FIG. 15.

FIG. 17 is an explanatory view of the manufacturing process continued from FIG. 16;

[Explanation of symbols]

 3. ． ． Electronic components, 30. ． ． Bonding wire, 5. ． ． Metal plating, 50. ． ． Outer layer circuit, 6. ． ． Electrodeposition film, 65. ． ． Adhesive sheet, 8. ． ． Heat sink, 9. ． ． Circuit board, 900. ． ． Recesses for mounting electronic components, 91-96. ． ． Insulating substrate, 97-99. ． ． Open hole, 971, 981, 991. ． ． Tapered inner wall,

Claims (1)

[Claims] 1. A method of manufacturing an electronic component mounting board, comprising: a circuit board; and an opening hole for forming an electronic component mounting recess provided in the circuit board; A step B of forming an opening hole having a tapered inner wall that expands from the front side surface to the back side surface of the circuit board, and a step C of coating the entire surface of the circuit board including the surface of the opening hole with metal plating. A step D of coating the surface of the metal plating with an electrodeposition film, and a step E of placing an exposure mask film for forming a wiring pattern on the front surface of the circuit board and irradiating the mask film with light. When,
The masking film on the circuit board is removed, and the circuit board is developed to remove the electrodeposition film around the opening hole, and the circuit board is etched to remove metal plating around the opening hole on the front surface. A method of manufacturing an electronic component mounting substrate, comprising: a G step of removing and an H step of removing the remaining electrodeposition film from the circuit board.