JPH04196261A - Manufacture of electronic part loading board - Google Patents

Abstract

PURPOSE:To enable the 42 alloy in high rigidity to be used while entirely removing the residues between respective leads by a method wherein a lead frame is formed of a Cu-plated 42 alloy material (stainless steel) to form a blackened film while the residues between outer leads are removed. CONSTITUTION:The whole surface of a lead frame 11A is plated with Cu, them the lead frame 11A is blackened insulating substrates 12 and the lead frame 11A are formed into one body so that outer leads 11a may be exposed from respective insulating substrates 12 simultaneously removing the first residual resins 61 between respective leads 11 using laser beams etc. Furthermore, the resins 61 are electrolytic-degreased in alkali solution to remove the second residual resins 62 sticking to the sides of the outer leads 11a. Finally, the whole body is electrolytic etched away also in the alkali solution to remove the exposed Cu plating 20 so as to completely expose an 42 alloy material. Through these procedures, the outer lead part can be composed of a material in high rigidity.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a board for mounting electronic components, and in particular to a method for manufacturing a board for mounting electronic components, in particular a method for manufacturing a lead frame that integrates a large number of leads from a 42 alloy material (stainless steel). The present invention relates to a method of manufacturing a board for mounting electronic components.

(Prior Art) Many various substrates for mounting electronic components have been proposed in the past, and the applicant has proposed, for example, the fourth substrate.
We have also proposed a board for mounting electronic components as shown in the figure. The electronic component mounting board shown in Fig. 4 is constructed by integrating an insulating base material on both sides of a metal lead frame, and includes the outer leads and tie bars of each lead making up the lead frame. A portion of the inner glue portion of the tie bar is configured to be exposed to the outside as an outer lead portion. That is, as shown in FIG. 7, for example, as shown in FIG. 7, after mounting electronic components on this electronic component mounting board, almost the entire board is sealed with a sealing resin, thereby forming an electronic component mounting device (100). This is what is considered to be.

The above types of substrates for mounting electronic components use prepreg resin material as the insulating base material, or otherwise integrate the insulating base material made of other materials with the lead frame via adhesive. Either it is formed by merging, or the integration is done by thermocompression bonding. On the other hand, a lead frame is made up of a large number of leads connected by tie bars, etc., so in the areas where these leads are concentrated, for example, as shown in Fig. 5, the distance between them is small. It is narrower.

When an insulating base material is thermocompression bonded to such a lead frame, a portion of the material such as the insulating base material will enter between the leads, and must be removed. In particular, the outer lead portion of each lead is exposed to the outside when the electronic component mounting device (100) as shown in FIG. 100) on another board, causing various problems. Not only that, but a portion of the outer lead portion of each lead is wrapped in the sealing resin as shown in Figure 7, and if there is any residue there, the sealing resin will cause damage. This also poses the problem of not being able to seal completely.

In particular, in recent electronic component mounting substrates, the spacing between the leats has become extremely narrow, and it is difficult to remove the residue located around these leats. Since each reed is lined up on the same plane, it is possible to mechanically remove both the top and bottom of each reat at once, or at least remove what remains between the closely spaced reeds. This cannot be done by mechanical means, and a method for removing this residue between the leads is eagerly awaited.

On the other hand, the lead frame is made of copper because it is easy to process and has good thermal conductivity, or the outer lead of the lead frame that makes up the lead frame is made of copper. , as described above, serves as an external connection terminal of an electronic component mounting apparatus (100) constructed using the electronic component mounting board.

Therefore, if this outer lead is made of a soft material such as copper, this outer lead will be easily deformed when mounting the electronic component mounting device (100) on another board, resulting in various inconveniences. may occur. Therefore, in order to make these outer lead parts hard, the entire lead frame has been made of 42 alloy material. As described above, when using the 42 alloy material, it is natural that it becomes necessary to take measures to increase the adhesion strength of the insulating base material to the material.

In short, in this type of electronic component mounting board, the lead frame must be made of 42 alloy material in order to increase the rigidity of the outer lead part, and it is necessary to make sure that there is no residue between each lead. As a result of the inventors' various studies on how to meet such demands,
The present invention was completed.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and the problems to be solved are ensuring the rigidity of the leads and the presence of residue between these leads.

It is an object of the present invention to provide a highly rigid 42 mm lead frame as a lead frame by only slightly changing a part of the conventional manufacturing method of this type of electronic component mounting board.
The object of the present invention is to propose a method for manufacturing an electronic component mounting board that can use an alloy material and has no residue between its leads.

(Means and operations for solving the problems) In order to solve the above problems, the means taken by the present invention are described with reference numerals used in the embodiments. A lead frame (IIA) made of 42 alloy material is coated with an insulating base material (IIA) on both sides.
) is integrated, and an electronic component mounting board (l) is made with an outer lead portion (lla) protruding from this insulating base material (12).
A method for producing O) including the following steps.

(1) Copper plating (2
0), and after blackening treatment, an insulating base material (12
) to the lead frame (IIA); (2
) a step of exposing the outer lead portion (lla) of each lead (11) from each insulating base material (12) and removing the first residual resin (61) between each lead (11) using a laser beam or the like; (3) A step of removing the second residual resin (62) that remains attached to the side surface of the outer lead part (Ila) by electrolytically degreasing the above material in an alkaline solution; This is a process of electrolytically etching the entire structure in an alkaline solution to remove the copper plating (20) exposed on the outer lead part (lla) and completely expose the 42 alloy material.

That is, the present invention is intended to ultimately manufacture the electronic component mounting board (10) as shown in FIGS. The first residual resin (61) and the second residual resin (62)
), and the copper plating (20) used only to form the blackened film is removed from the outer lead part (l).
1a) to obtain a desired electronic component mounting board (10).

In the manufacturing method of the present invention, (1) copper plating (20) is applied to the entire surface of the lead frame (IIA),
It goes without saying that the insulating base material (12) is integrated with the lead frame (IIA) after blackening treatment, and the following steps are important. In addition, the lead frame (l
The reason why 42 alloy material is used for IA) is to achieve the purpose of constructing the outer lead part (lla) with a highly rigid material when it is finally used as the electronic component mounting board (10). be. Also, during this process, excess resin from the insulating base material etc.
a), and a first residual resin (61) and a second residual resin (62) as shown in FIG. 1(b) are formed.

After doing the above, (2) the outer lead portion (lla) of each lead (11) is exposed from each insulating base material (12), and the first residual resin (61) between each lead (11) is exposed. In the following embodiment, the outer lead portion (lla
), the release film (30) is disposed on the outer lead portion (lla), so that the work of exposing the outer lead portion (lla) can be easily performed.

(3) By electrolytically degreasing the above material in an alkaline solution, the second residual resin (62) remaining attached to the side surface of the outer lead portion (lla) is removed. This step is very important. The reason is that originally in the process (2) above,
It would be better to remove the first residual resin (61) and second residual resin (62) adhering to each outer lead part (lla) at the same time.
) can not be easily removed, so as in (3), the second residual resin (62)
2) is strongly removed by electrochemical means. That is, by electrolytically degreasing each outer lead part (lla), the outer lead part (lla) is activated, and the copper plating (20
) is forcibly lifted and removed by slightly etching the second residual resin (62).

After going through the above steps, the outer lead part (lla
The second residual resin (62) adhering to both the left and right sides of (4) has been completely removed. By removing the copper plating (20) exposed on the lead portion (lla), it is possible to completely expose the 42 alloy material.

Also, the reason for electrolytic etching is that the outer lead portion (11a) of the copper plating (20) to be removed is particularly
This is to efficiently remove the copper plating (20) adhering to the side surface of the plate. The copper plating (2) adhering to the outer lead part (lla), especially on the sides, could not be completely removed by conventional spray or dip etching.
0) can now be performed completely efficiently by electrolytic etching.

By doing the above, the outer lead part (lla) will be made of only the original highly rigid 42 alloy material, and each outer lead part (lla) will have an equivalent extra material (copper plating). 20) Since the copper plating (20) itself is easily oxidized, the copper plating (20) is also redundant for the outer lead portion (lla)). ) will be completed.

Note that the REET (11) located inside the insulating base material (12)
) is there a blackened film formed by blackening the copper plating (20)?
12), and makes the adhesion of both insulating base materials (12) to the lead frame (IIA) or each lead (11) sufficiently strong. Of course, even if this blackened film exists in the electronic component mounting substrate (10), it will not cause problems such as migration.

(Example) Next, the present invention will be described in detail according to an example shown in the drawings.

Each of (a) to (e) in FIG. 1 sequentially shows changes in the surrounding situation of each outer lead portion (11a) during each step of the present manufacturing method, and in particular, FIG. (a) shows a state in which copper plating (20) is applied to the surface of a lead frame (IIA) consisting of a large number of boards (11). In other words, in the state shown in FIG. 1(a), the entire lead frame (IIA) as shown in FIG. 5 is plated with copper (20).

In addition, in this embodiment, a so-called multi-piece electronic component mounting board (10) is shown, and for example, the fifth
The lead frame (11A) as shown in the figure is formed to be continuous vertically and horizontally.

Accordingly, each insulating base material (12) to be integrated into this lead frame (IIA) is also integrated into this lead frame (IIA).
It is made into a very large plate shape corresponding to the size of A). In this case, in this example, each insulating base material (
12) into the lead frame (IIA), the upper and lower surfaces of the outer lead portion (lla) of each lead (11) are coated with a release film (30) as shown in FIG.
Later, each outer lead 1 (I
This makes it easier to expose IA).

In this example, the thickness of the release film (3o) is approximately 10 μm. The reason for this is that the release film (30) is blackened to improve its adhesion to the insulating base material (12), which will be described later. This is to maintain the minimum thickness that will prevent the material from being removed.

The following explanation will focus on one electronic component mounting substrate (10), without assuming that a large number of electronic component mounting substrates (10) as described above are used.

As mentioned above, for the lead frame (IIA),
As shown in Fig. 2, a release film (30) is placed in a portion corresponding to the outer lead portion (11a), and then each insulating base material (12) is thermocompression bonded to both sides of the lead frame (IIA). It is. The steps up to this point are the steps (1) mentioned in the claims. Then, a copper foil (13a) is formed on the back surface of each of the insulating base materials (12) by pasting or plating the foil, and by subjecting the copper foil (13a) to a predetermined mask etching process. , a conductor circuit (13) as shown in FIG.
). In this embodiment, in this case, a through hole (14) is formed to penetrate through each insulating base material (12) and each hole (11).
Electrical continuity is established between the conductor circuit (13) and the conductor circuit (13).

Then, the outer lead part (lla
), the insulating base material (12) on the outer lead portion (lla) is removed. Removal in this case is carried out, for example, by making a cut around a predetermined portion of the insulating base material (12) by counterbore processing or racer processing, and a release film (30) is placed on the underside of the insulating base material (12). Since it is placed in place, it can be easily removed. The state in which this excess insulating base material (12) has been removed is shown in FIGS. 4 and 6.

In this way, after removing the unnecessary insulating base material (12) and release film (30), as shown in FIG. 6 and FIG. 1(b), each outer lead portion 1:11a
) around the first residual resin (61) and the second residual resin (6
2) Or exists. The first residual resin (61) and the second residual resin (62) must be removed as described above, but for this purpose, each resin 1"(1"
The first residual resin (61) located between 1) is removed by laser light or the like. This is the step (2) mentioned in the claims, and is the state shown in FIG. 1(C). Here, the release films (30) on both the upper and lower surfaces of each outer lead part (lla) are completely removed, and only the copper plating (20) or its blackened product is exposed.

As shown in FIG. 8, (3) by electrolytically degreasing the above material in an alkaline electrolytic degreasing solution, the second residual resin (62) remains attached to the side surface of each lead (11). ). As a result, each -)
”(11) is completely cleaned, and the surface of each outer lead part (lla) is also coated with copper plating (2).
0) or slightly etched, so this copper plating (20
) The second residual resin (62) adhering to the surface is in a so-called state. Here, if the second residual resin (62) is forcibly removed by means such as jet scrubbing, the second residual resin (62) can easily peel off.

Finally, as shown in (d) and (e) of Figure 1, (
4) As shown in the figure, the entire structure as described above is electrolytically minced using an alkaline electrolytic etching solution to remove the copper plating exposed on each outer lead part (lla).
20) to completely expose the 42 alloy material. In other words, at this stage, the outer lead part (lla
) If the copper plating (20) exposed on the copper plating (20) is removed by etching, the 42 alloy material that is the material of each outer lead part (lla) will be completely exposed, and if the copper plating (20) is Even if some of the second residual resin (62) remains attached, the copper plating (20) supporting it will be gone, so the second residual resin (62) will also be completely removed. It is.

Here, in the electrolytic alkaline degreasing, the electrolytic solution is a mixture of sodium hydroxide and a degreasing catalyst (IC-220 manufactured by Evalany Silite Co., Ltd.) containing sodium hydroxide as the main component, or the concentration of each is 70 to 300 g/ l 30~1
40g/L.

This is then subjected to electrolytic degreasing as shown in FIG. The electrolytic conditions were 125 A/m2, but copper plating (2
0) The second residual resin (62) above can be removed.

In alkaline electrolytic etching, a mixture of ammonium carbonate and aqueous ammonia is used as the electrolyte, or the concentration of each is (I) 50 to 200 g/L, 2O
-100 cc/J2, and electrolytic etching is performed as shown in FIG. Copper etching is possible under the electrolytic conditions of 115 A/m2 or under all solution concentration conditions (at room temperature for 30 minutes).

By doing the above, each outer lead part (
lla) or 42 alloy material is completely exposed and there is no adhesion of the first residual resin (61) or the second residual resin (62), as shown in FIG. 4 or FIG. The electronic component mounting board (10) in this state is now completed.

In addition, the electronic component mounting board (1
0), as shown in FIG. 13) by bonding wires (41), and then sealed with a sealing resin (50) so that each outer lead part (lla) is exposed, thereby completing the electronic component mounting device (100). It is. In this electronic component mounting device (100), each outer lead portion (ll
a) First residual resin (61) or second residual resin (6
2) is not present, the sealing resins (50) located above and below each outer lead portion (lla) in the drawing are completely integrated and firmly connected.

(Effects of the Invention) As detailed above, in the present invention, as exemplified in the above embodiment, "a large number of leads (11) are integrated to form a lead frame (IIA) made of 42 alloy material on both sides of the lead frame (IIA)". Insulating base material (12
) are integrated, and the outer lead portion (lla) protrudes from the insulating base material (12).
0), including the following steps.

(1) Copper plating (2
0), and after blackening treatment, an insulating base material (12
) to the lead frame (IIA): (2
) a step of exposing the outer lead portion (lla) of each lead (11) from each insulating base material (12) and removing the first residual resin (61) between each lead (11) using a laser beam or the like; (3) A step of removing the second residual resin (62) that remains attached to the side surface of the outer lead part (lla) by electrolytically degreasing the above material in an alkaline solution; Electrolytic etching is performed on the whole thus prepared in an alkaline solution to remove the copper plating (20) exposed on the outer lead part (lla) and completely expose the 42 alloy material. Since the component mounting board (10) has been manufactured, it is possible to use a highly rigid 42 alloy material as the lead frame by slightly changing some of the conventional manufacturing methods for this type of electronic component mounting board. At the same time, it is possible to manufacture a substrate for mounting electronic components without any residue between the leads.

In other words, the electronic component mounting substrate (lO) formed by this manufacturing method has an insulating base material (lO) which is an important component thereof.
12) is a lead frame (IIA) or a lead (1
1) They are firmly adhered by the blackened copper plating (20) film formed on them, and each of the holes protrudes outward from each insulating base material (12).
) is made of highly rigid 42 alloy material itself, so the electronic component mounting device (100) constructed using this electronic component mounting board (10) can be made highly durable. be.

In addition, since there is no residue at all between the outer leads (Ila) of this electronic component mounting board 10), it can be used to mount the electronic component mounting device (100). When each outer lead part (1
1. Sealing resin (50) to be located above and below a)
This allows the electronic component mounting device (100) to be highly durable.

[Brief explanation of the drawing]

Each of (a) to (e) in FIG. 1 is an enlarged sectional view of each outer lead portion showing changes in the periphery of each outer lead portion according to an embodiment of the present invention, and FIG. 2 is an insulating base on both sides of the lead frame. Fig. 3 is an enlarged cross-sectional view when the materials are integrated;
FIG. 4 is a cross-sectional view showing a state in which the insulating base material on each outer lead part has been removed, FIG. 5 is a plan view showing an embodiment of the lead frame used in carrying out the present invention, and FIG. FIG. 7 is a plan view of the insulating base material integrated into the necessary parts of the lead frame, FIG. 7 is a cross-sectional view of an electronic component mounting device constructed using the electronic component mounting board manufactured according to the present invention, and FIG. It is a schematic sectional view showing the state where electrolytic degreasing is carried out in electrolytic degreasing liquid. Explanation of symbols 10...Electronic component mounting board, 11...Lead, II
A...Lead frame, lla...Outer lead portion, 12...Insulating base material, 13...Conductor circuit, 20...
- Copper plating, 30... Release film, 40... Electronic components, 50... Sealing resin, 61... First residual resin, 6
2...Second residual resin. that's all

Claims (1)

[Claims] A board for mounting an electronic component, in which a large number of leads are integrated, an insulating base material is integrated on both sides of a lead frame made of 42 alloy material, and an outer lead portion protrudes from the insulating base material, A manufacturing method that includes the following steps: (1) Copper plating is applied to the entire surface of the lead frame,
A step of integrating the insulating base material into a lead frame after blackening the insulating base material; (2) exposing the outer lead portion of each lead from the insulating base material, and first residual resin between each lead; (3) A step of removing the second residual resin remaining attached to the side surface of the outer lead portion by electrolytically degreasing the above material in an alkaline solution; ( 4) A step of electrolytically etching the entire structure as described above in an alkaline solution to remove the copper plating exposed on the outer lead portion and completely expose the 42 alloy material.