JP2818904B2 - Substrate for mounting electronic components - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Industrial Application Field) The present invention relates to a substrate for mounting an electronic component, which is entirely sealed by means such as transfer molding, except for a part of an outer lead, after mounting the electronic component. It is about.

(Prior Art) There are various types of substrates on which electronic components are mounted. As an example of an electronic component mounting substrate for mounting electronic components to form a so-called electronic component mounting apparatus, there is a first type.
The configuration shown in FIG. 10 is employed. In other words, the electronic component mounting board shown in FIG. 10 has a large number of outer leads (11) by mounting the electronic component (20) thereon and sealing the whole with the sealing resin (30). ) Is configured to protrude outward.

By the way, in such an electronic component mounting board, the surface of the conductor pattern is generally plated with Ni-Au to ensure connection with the electronic component. This Ni-Au plating is really necessary for connecting parts with electronic parts, mounting parts for electronic parts, etc., dummy patterns for preventing warpage provided on electronic parts mounting boards,
It is not necessary for a power supply pattern or a ground pattern. Therefore, a solder resist is generally printed on that portion.

However, the electronic component (20) is mounted on an electronic component mounting substrate in which the entire surface of the dummy pattern, power supply pattern, ground pattern, or the like (hereinafter, referred to as a ground pattern, etc.) is covered with a solder resist, and sealing as described above is performed. When the sealing with the resin (30) is performed almost entirely, the following mechanical or structural problems occur. That is, the dummy pattern is formed over a large area to prevent warpage of the entire electronic component mounting substrate, increase mechanical strength, and improve heat dissipation, and the power supply pattern is large. The ground pattern must be thick to allow current to flow, and the ground pattern must be thick to stabilize the ground. Generally, the solder resist has a weak adhesion on a conductor pattern having such a large area, and is easily peeled off by heating or the like.
0) Even if the adhesion between the solder resist is good,
Since the adhesiveness between the solder resist and the conductor pattern is not sufficient, a peeling phenomenon occurs between the conductor pattern and the solder resist when assembling the electronic component mounting apparatus or during long-term use. In such a case, the electronic component mounting substrate located inside is not sufficiently supported by the sealing resin (30). For example, when the electronic component (20) generates heat, the electronic component mounting substrate is sealed. Due to the difference in thermal expansion between the resins (30), the sealing resin (30) itself may be deformed,
In some cases, cracks that allow moisture to enter the sealing resin (30) itself may occur.

Therefore, the present inventors have conducted intensive studies on how to prevent the above-mentioned problems from occurring, and as a result, in particular, a conductor pattern to be a ground pattern or the like and a sealing resin (30) The present inventors have realized that improving the adhesion to the resin produces good results and completed the present invention.

(Problems to be Solved by the Invention) The present invention has been made based on the above circumstances, and a problem to be solved is to improve the adhesion of the sealing resin (30) to the electronic component mounting substrate. is there.

The object of the present invention is to improve the adhesiveness with a sealing resin that covers the whole later by devising a method of forming a solder resist with respect to a conductor pattern to be a ground pattern or the like. An object of the present invention is to provide an electronic component mounting substrate having a simple configuration in which a peeling phenomenon does not occur between the electronic component mounting resin and the resin.

(Means for Solving the Problems) In order to solve the above problems, the means adopted by the present invention will be described with reference numerals used in the embodiments. Outer lead (1
1), an insulating base material (12) integrated on both surfaces of the inner ends of the outer leads (11), and the insulating base material (12)
Conductor pattern (13) formed at least on the surface side of
In order to protect the solder resist (14) formed on the conductor pattern (13) on the electronic component mounting board (10) having the solder resist (14) and the solder resist formed on the surface thereof, A substrate (10) for mounting an electronic component, wherein an opening (14a) for exposing the conductive pattern (13) or the insulating base material (12) located inside the conductive pattern (13) in a mesh shape is formed. ".

That is, the electronic component mounting board (10) according to the present invention.
Is formed by forming a solder resist (14) in a so-called mesh shape on the conductor pattern (13).

(Operation of the Invention) The operation of the electronic component mounting board (10) configured as described above will be described below, and this operation will be described separately for each embodiment described later.

Regarding the electronic component mounting board (10) according to the first embodiment The electronic component mounting board (10) according to the first embodiment shown in FIGS. 1 and 2 has a conductor pattern (13) to be a ground pattern or the like. ) Is formed on substantially the entire surface of the insulating base material (12) on the back surface side, and a solder resist (14) is formed on the conductive pattern (13) in a mesh shape as shown in FIG. It is. Therefore, in the electronic component mounting board (10), a part of the conductor pattern (13) is exposed from each opening (14a) formed in the solder resist (14). Since the conductive pattern (13) is generally formed of a metal such as copper, the adhesive force with the sealing resin (30) formed later is relatively higher than that with the solder resist (14). This conductor pattern (13) is solder resist (14)
Partially exposed from the opening (14a) of the electronic component mounting substrate (10) with respect to the sealing resin (30)
This means that the adhesiveness is improved as compared with the conventional case.

If the conductor pattern (13) is formed of copper, the opening (14) of the solder resist (14) is formed.
The part exposed from a) can be subjected to a so-called blackening treatment or a roughening treatment such as polishing.
0) can be further improved.

Furthermore, in this electronic component mounting board (10),
A large number of openings (14
Since the solder resist (14) formed with a) has irregularities, the sealing resin (30) formed later on the electronic component mounting board (10) is made of an insulating base material (12). The attempt to expand and contract relatively to the plane direction of (1) is prevented by the unevenness of the solder resist (14). Therefore, the solder resist (14) having the unevenness is used as the electronic component mounting substrate (10).
This prevents peeling off from the sealing resin (30) formed later.

In addition, the electronic component mounting board (10) according to the first embodiment.
In the above method, a plating process for a conductor pattern (13) to be a ground pattern or the like can be performed at low cost. That is, generally, a portion of the conductor pattern (13) connected to the electronic component (20) by the bonding wire (21) is plated with gold in order to make a good connection. The conductor pattern (13) to be equal or the like has a relatively large area in order to make its electrical function sufficient.
When gold plating is applied to the conductor pattern (13) to which the bonding wire (21) is connected, the entire electronic component mounting substrate (10) is immersed in a plating solution. In such a case, if the conductor pattern (1
If 3) is exposed, a large amount of gold plating will be applied to this conductor pattern (13).

However, in the electronic component mounting board according to the present invention, the conductor pattern (13) serving as a ground pattern or the like is only exposed from each opening (14a) of the solder resist (14). Even if gold plating is performed, the amount is very small. Therefore,
When gold plating is applied to this electronic component mounting board,
The cost can be greatly reduced as compared with the conventional one.

Regarding the electronic component mounting board (10) according to the second embodiment In the electronic component mounting board (10) according to the second embodiment shown in FIGS. 6 and 7, the conductor on the side to be a ground pattern or the like is used. It is natural that the solder resist (14) formed on the pattern (13) has a large number of openings (14a) and is configured as a mesh-like one. The structure itself is also configured as a mesh-like solder resist (14). Therefore, in the electronic component mounting board (10), the solder resist (1
Part of the insulating base material (12) is exposed through the openings (14a) in 4). This substrate has a number of fine holes in the anchor formed when a copper foil to be used as a conductor pattern is applied by pressing, and the unevenness of the holes in the anchor causes the electronic component mounting substrate (10 In (2), the sealing resin (30) formed later passes through each opening (14a) of the solder resist (14) to the insulating base material (12), which has a very good adhesion to the sealing resin (30). It can be in direct contact. In other words, in the electronic component mounting board (10), since the insulating base material (12) itself is exposed to the outside through each opening (14a) of the solder resist (14), The adhesion between the substrate (10) and the sealing resin (30) is greatly improved.

In the electronic component mounting board (10) of the second embodiment, a large number of openings (14a) are formed in the solder resist (1).
The fact that the expansion and contraction of the sealing resin (30) in the surface direction of the insulating base material (12) due to the unevenness formed due to the presence of the substrate in the electronic component mounting substrate (10) of the first embodiment is prevented. ) Is the same.

The electronic component mounting board (10) according to the second embodiment.
In, at least a conductor pattern (13) to be a ground pattern or the like is formed in a mesh shape, and the entire conductor pattern (13) is covered with a solder resist (14). Substrate (1
When gold plating is performed on a predetermined portion of (0), no gold plating is formed on the conductor pattern (13) serving as the power supply layer or the ground layer. Therefore, the cost of the electronic component mounting substrate (10) can be further reduced than that of the first embodiment.

(Embodiment) Next, an electronic component mounting board (10) according to the present invention will be described according to each embodiment shown in the drawings, together with a method of manufacturing the same.

Embodiment 1 FIGS. 1 to 5 show an electronic component mounting board (10) according to a first embodiment of the present invention. This electronic component mounting board (10) is basically integrated on both sides of a number of outer leads (11) projecting outward after sealing and the inner ends of these outer leads (11). Insulating base material (12)
And a conductor pattern formed on at least the surface side of the insulating base material (12), and a solder resist (14) formed on the surface to protect the conductor pattern. As shown in FIG. 2, the electronic component mounting board (10) has an electronic component (20) mounted on the upper side of the drawing and is connected to each of the conductor patterns (13) on the upper side of the drawing. After being electrically connected by the bonding wire (21), the end of each outer lead (11) is projected outward, and substantially the entire electronic component mounting board (10) is transferred by means such as transfer molding. An electronic component mounting device is obtained by coating with a sealing resin (30). And
The conductor pattern (13) located on the lower side of FIG. 2 is a ground pattern or the like, and the conductor pattern (13) is, as shown in FIG.
It is formed on almost the entire back surface of (0).

In this electronic component mounting board (10), as shown in FIG. 2, conductors are provided on both sides of a lead frame in which a number of outer leads (11) and the like are integrally formed in a single plate. The basic configuration is that the insulating base material (12) on which the pattern (13) is formed is integrated, and the conductor pattern (13) is exposed on at least both surfaces thereof.

Of the conductor patterns (13), those located on the upper side in FIG. 2 mainly constitute signal lines in which the mounting portion for the electronic component (20) performs electrical routing for the electronic component (20). The through-holes formed in the insulating base material (12) are electrically connected to the inner ends of the outer leads (11), so that the outer leads (11) and the respective conductors on the upper side of the figure are connected. It is selectively connected to the signal line of the pattern (13). On the other hand, the conductor pattern (13) located on the lower side of FIG. 2 is to be a ground pattern or the like, and this conductor pattern (13) may be a part of the upper conductor pattern (13) if necessary. Are electrically connected to each other by a through hole or the like. As described above, the conductor pattern (13) serving as the ground pattern is a so-called solid pattern formed on substantially the entire surface of the lower insulating base (12).

Then, as shown in FIG. 1, a solder resist (14) is formed on the conductor pattern (13) to be a ground pattern or the like located on the lower side of FIG. This solder resist (14) is not formed on the entire surface of the conductor pattern (13) which is a solid pattern.
As shown in the figure, it is formed in a so-called mesh shape having a large number of openings (14a).
According to a), the conductor pattern (13) to be a ground pattern or the like is partially exposed.

Next, a method of manufacturing the electronic component mounting substrate (10) will be described. The electronic component mounting substrate (10) forms a large number of electronic component mounting substrates (10) at a time, that is, a large number of individual substrates. It is formed by integrating a sheet-like large-area insulating base material (12) on both sides of a sheet-like lead frame in which many outer leads (11) are integrated. Is what is done. In addition, a release mask (11a) is arranged on both surfaces of a portion protruding outward of each outer lead (11), and then each insulating base material (12) is integrated.

On the surface of an insulating substrate (12) integrated on both sides of a lead frame consisting of a large number of outer leads (11) etc., a metal foil to be a conductor pattern (13) is affixed before or after integration The predetermined conductor pattern (13) is formed by subjecting the metal foil to a predetermined etching process or the like in a conventional manner. FIGS. 3 and 4 show the result of the above steps.

Then, as shown in FIG. 5, a solder resist (14) is formed on the surface of the conductor pattern (13) serving as a ground pattern or the like by an ordinary method. In this case, the solder resist (14) is formed in a so-called mesh shape. It is formed in.

After that, a predetermined plating process is applied to each conductor pattern (13), and then the sheet-shaped insulating base material (12) is partially removed, so that the outer ends of the outer leads (11) should be formed. Expose part. In this case, the release mask (11a) on each outer lead (11) improves the work of exposing the outer end of each outer lead (11) and exposes each outer lead (11). The remaining portion of the insulating base material (12) is prevented from adhering to the portion.
Next, by cutting the continuous outer leads (11) and the like into a predetermined shape, a fixed electronic component mounting substrate (10) is cut out.

Embodiment 2 FIGS. 6 to 9 show an electronic component mounting board (10) according to a second embodiment of the present invention. The electronic component mounting board (10) has a ground pattern and the like. This is the same as the electronic component mounting board (10) in the first embodiment, except that the conductor pattern (13) to be formed is meshed as shown in FIG.

That is, the electronic component mounting board (1
In (0), when the metal foil attached to the front surface side of each insulating base material (12) is etched, the mesh-shaped conductor pattern (13) is also used for the metal foil on the rear surface side, such as a ground pattern. An etching mask is provided and an etching process is performed. As a result, as shown in FIGS. 8 and 9, the conductor pattern (13) serving as a ground pattern or the like has a large number of openings. Part of 12) will be exposed. Since the conductor pattern (13) has a mesh shape, the entire surface is electrically integrated.

Then, a solder resist (14) having a large number of openings (14a) is formed on the conductor pattern (13) serving as a mesh ground pattern or the like by the method described in the first embodiment. Naturally, the opening (14a) of each solder resist (14) is smaller than the opening on the conductor pattern (13) side, and as shown in FIGS. 6 and 7, the solder resist (14) Denotes a surface that covers the entire surface of the conductor pattern (13) serving as a power supply layer or a ground layer.

In the first and second embodiments, the signal lines are mainly formed on the upper surface of the drawing, and the ground patterns and the like are formed on the lower surface of the drawing. However, the ground patterns and the like are formed on the upper surface of the drawing, and the signal lines are formed on the lower surface of the drawing. In this case, the solder resist can be formed in a mesh shape in the same manner, and the solder resist on the signal line can be formed in a mesh shape to improve the adhesion strength.

(Effects of the Invention) As described in detail above, in the present invention, as illustrated in each of the above-described embodiments, “a large number of outer leads (1
1), an insulating base material (12) integrated on both surfaces of the inner ends of the outer leads (11), and the insulating base material (12)
Conductor pattern (13) formed at least on the surface side of
And a solder resist (14) formed on the conductor pattern (13) on the electronic component mounting board (10) having a solder resist formed on the surface thereof and (14) to protect the solder resist. And an opening (14a) for exposing the conductive pattern (13) or the insulating base material (12) located inside the conductive pattern (13) in a mesh shape. " By devising a method of forming a solder resist on a conductor pattern to be a ground pattern or the like, the adhesion with a sealing resin that covers the whole later is improved, and a peeling phenomenon occurs between the sealing resin and the sealing resin. An electronic component mounting substrate that does not occur can be provided with a simple configuration.

That is, according to the electronic component mounting board (10) of the present invention, the conductor pattern (13) serving as a ground pattern or the like is provided.
Solder resist (1) with many openings (14a)
Since 4) is formed to expose a part of the conductor pattern (13) or a part of the insulating base material (12), a sealing resin for sealing the electronic component mounting board (10) is formed. The adhesiveness with (30) can be made very good. Therefore, according to the electronic component mounting board (10), no peeling occurs between the board and the sealing resin (30), thereby providing high electrical reliability and excellent durability. It can be.

In addition, the electronic component mounting board (10) having the above-mentioned effects is provided with a conductor pattern (1) serving as a ground pattern or the like.
3) Since it can be manufactured by forming a large number of openings (14a) in the solder resist (14) covering the top, conventional equipment can be used and it can be provided at low cost. is there.

[Brief description of the drawings]

FIG. 1 is a rear view showing one embodiment of an electronic component mounting substrate according to the present invention, FIG. 2 is a cross-sectional view of the electronic component mounting substrate, and FIG. 3 is an electronic component mounting substrate after a conductive pattern is formed. 4, FIG. 4 is a cross-sectional view, and FIG. 5 is a back view of the electronic component mounting substrate after solder resist printing. 6 to 9 show another embodiment of the present invention. FIG. 6 is a rear view of an electronic component mounting substrate, FIG. 7 is a cross-sectional view thereof, and FIG. FIG. 9 is a rear view of the electronic component mounting board, and FIG. 9 is a sectional view thereof. FIG. 10 is a cross-sectional view when an electronic component mounting apparatus is configured using a conventional electronic component mounting substrate. Explanation of reference numeral 10: board for mounting electronic components, 11: outer lead, 12
... insulating base material, 13 ... conductor pattern, 14 ... solder resist, 14a ... opening, 20 ... electronic components, 30 ... sealing resin.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 23/28-23/30 H01L 21/56

Claims (1)

(57) [Claims] A plurality of outer leads protruding outward after sealing; an insulating base material integrated on both surfaces of inner ends of these outer leads; and an insulating base material formed on at least a surface side of the insulating base material. An electronic component mounting substrate comprising a conductive pattern, and a solder resist formed on the surface to protect the conductive pattern, wherein the solder resist formed on the conductive pattern is formed in a mesh shape, and the conductive pattern or An electronic component mounting board, wherein an opening is formed for exposing the insulating base material located inside thereof in a mesh shape.