JPH0445986B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a semiconductor mounting board, particularly a circuit board on which a conductive circuit is formed and a semiconductor element is to be mounted, and a circuit board that is integrally fixed to the circuit board. The present invention relates to a semiconductor mounting board comprising a lead frame for ensuring conduction with the outside.

(Prior Art) Semiconductor mounting generally consists of a circuit board on which a conductor circuit is formed and a semiconductor element is to be mounted, and a lead frame that is integrally fixed to this circuit board to ensure continuity with the outside. In the case of the substrate, a semiconductor device can be constructed by electrically connecting a conductive circuit or a lead frame and the semiconductor element using a bonding wire or the like. This semiconductor mounting board is formed as a semiconductor device by sealing the mounted semiconductor element and circuit board with resin or the like, with the end of the lead frame protruding as an external connection terminal. It is.

By the way, in the case of a conventional semiconductor mounting board of this kind, a circuit board on which a conductor circuit is formed is formed, and this is fixed to a lead frame using an adhesive or the like. Bonding terminals on the circuit board that are electrically connected to the frame are formed at the ends of the circuit board 31 so as to be easily connected to the lead frame 33 with bonding wires 35, etc., as shown in FIG. . Further, a circuit board 31 on which a conductor circuit 32 is formed
is generally formed into individual pieces by shearing using a press or the like for reasons such as increasing manufacturing efficiency. When forming the circuit board 31 and the bonding terminals 36 in this manner, the following disadvantages arise in the current situation where semiconductor mounting boards are required to have higher density. In other words, when the rotating substrate 31 is sheared using a press or the like and formed into individual pieces, the bonding terminals 36
As shown in FIG. 7, a curved surface 37 is formed at the end of the substrate where the curved surface 37 is formed. When this curved surface 37 coincides with the position of the bonding terminal 36, the tip 38 of the jig for holding and fixing the bonding wire 35 moves downward in the figure to perform wire bonding. If the wire 35 moves to the left in the figure, not only will bonding not be performed accurately using the bonding wire 35, but the wire 35 that has been painstakingly bonded may be removed.

The bonding terminal 36 on the circuit board 31,
If it has to be formed at the end of the circuit board 31, the arrangement of the various semiconductor elements 20 to be mounted on the circuit board 31 becomes a problem. That is, with the above limitations, each semiconductor element 20 must be placed in the center of the circuit board 31. This means that
In recent years, high-density packaging has been required for semiconductor mounting boards, which require a large number of semiconductor elements 20.
This is a considerable constraint.

Moreover, as mentioned above, the circuit board 31
Connect the upper bonding terminal 36 to the circuit board 31.
If the conductor circuits 32 on the circuit board 31 must be formed at the ends of the circuit board 31 and the various semiconductor elements 20 must be brought to the center, the conductor circuits 32 on the circuit board 31
must be formed accordingly.
In other words, the conductor circuit 32 on the circuit board 31 must be formed as a fairly complex one.

Furthermore, when connecting the bonding terminals 36 on the circuit board 31 and the lead frame 33 using the bonding wire 35, it is generally necessary to apply silver plating or the like to the lead frame 33 side in order to make a good bonding connection. . This silver plating is lead frame 33
The bonding wire 35 may be contaminated by various operations when bonding the rotating board 31 with the adhesive 34 or the like, and the bonding wire 35 after bonding may be contaminated due to chemical changes or moisture caused by this contamination. This may cause the wire to break. Therefore, it is better to avoid directly connecting the bonding wire 35 to the lead frame 33 side as much as possible.

Therefore, as a result of intensive research in order to resolve the insufficiency of the conventional technology for this type of semiconductor mounting board mentioned above, the present inventors have determined that the conduction between the semiconductor element mounted on the circuit board and the lead frame will be improved. The present invention was completed based on the new finding that good results can be obtained by performing the process using a so-called through hole formed through the circuit board and lead frame.

(Problems to be Solved by the Invention) The present invention has been made based on the above-mentioned circumstances. These problems include the difficulty in bonding the increasingly required semiconductor mounting substrate and the difficulty in routing circuits for bonding.

The purpose of the present invention is to not only be able to perform bonding reliably and easily, but also to be able to simplify the conductor circuit on the circuit board. It is an object of the present invention to provide a semiconductor mounting board having a simple structure that can be used and manufactured.

(Means for Solving the Problems) The means taken by the present invention to solve the above problems will be explained with reference to FIGS. 1 to 5 corresponding to the embodiments. a circuit board 11 on which a semiconductor element 20 is to be mounted;
In this semiconductor mounting board, the circuit board 11 and the lead frame 13 are provided with a through hole 15 that passes through them, and the lead frame 13 is integrally fixed to the circuit board 11 to ensure conduction with the outside. A semiconductor mounting board 10 characterized in that a conductor layer 16 is formed in the hole 15 to directly electrically connect a part of the conductor circuit 12 on the circuit board 11 and a part of the lead frame 13. be.

This structure will be explained in more detail with reference to a specific example shown in the drawings. For example, FIG. 1 shows a longitudinal cross-sectional view of a semiconductor mounting substrate 10 according to the present invention. This semiconductor mounting board 10 includes a circuit board 11 on which a conductor circuit 12 is formed and on which a semiconductor element 20 is to be mounted, and a circuit board 11 that is integrally fixed to this circuit board 11 to ensure conduction with the outside. The circuit board 11 and the lead frame 13 are bonded together using an adhesive 14.
It is integrally constructed by. In this semiconductor mounting board 10, through holes 15 penetrating the circuit board 11, lead frame 13, and adhesive 14 are formed at appropriate locations, and each through hole 15 is provided with a conductor. A layer 16 is formed, and the through holes 15 and the conductor layer 16 form so-called through holes.

In other words, in the case of the semiconductor mounting board 10, appropriate parts of the conductor circuit 12 formed on the circuit board 11 and the lead frame 13 are electrically connected by the conductor layer 16 in the through hole 15. be.
Of course, since the lead frame 13 itself serves as an external connection terminal, each of the plurality of leads is configured to be electrically independent, and each through hole 15 and conductor layer 16 is connected to the circuit board 1.
The conductor circuit 12 on the conductor circuit 1 is connected to an electrically independent appropriate location.

These through holes 15 and conductor layer 16 may be formed at the edge of the circuit board 11 as shown in FIGS. 1 and 3, but they may be formed on the edge of the circuit board 11 as shown in FIGS. As such, it may be formed and implemented in the central portion of the circuit board 11. In this way, when the through hole 15 and the conductor layer 16 are formed in the center part of the circuit board 11, a large number of semiconductor elements 20 are mounted and placed on each lead frame.
3, the configuration of the conductor circuit 12 itself can be simplified. The reason is that through hole 1
5 and the conductor layer 16 can be freely selected, and therefore the conventional restriction that bonding terminals must be formed at the periphery of the circuit board 11 is completely eliminated.

Furthermore, in carrying out the present invention, as shown in FIGS. 1 and 2, the above structure may be adopted without processing the lead frame 13 at all, but as shown in FIGS. As shown, lead frame 13
A recess 1 for storing a semiconductor element 20 in a part of the
7 may be formed and implemented. In this way, when the recess 17 is formed in the lead frame 13, the circuit board 11 and the lead frame 13
The conductor layer 16 can be easily formed in the through hole 15 formed by penetrating the conductor layer 16. This is because the length of the through hole 15 can be actively shortened.

Next, the semiconductor mounting board 1 having the above configuration is assembled.
The manufacturing method employed to form 0 will be explained. FIG. 5 is a diagram for explaining a typical manufacturing method thereof, and the explanation will be given below in the order of process codes .about. shown in FIG.

First, a through hole is formed in a double-sided copper-clad resin substrate that is to become the circuit board 11. In this case, the through hole is
Although it is different from the through hole 15 described later,
It is also possible to form what will become the through hole 15 at the same time. Further, the copper foil stretched on both sides of the resin substrate serves as a conductor circuit 12, which will be described later. Electroless plating or electrolytic copper plating is used to conduct the copper foils located on the front and back sides of the resin substrate in each through hole of the resin substrate formed in this way. Further, a desired etching resist is formed using a photosensitive dry film or the like, and unnecessary portions of copper are etched using this etching resist, thereby forming a conductor circuit 12 having a desired shape. And this circuit board 1
1. Print the solder resist on the specified location,
Nickel plating and gold plating are applied to the parts to which the bonding wires 21 are connected, and the circuit board 11 is cut into a predetermined shape to obtain the circuit board 11 in the form of individual pieces.

Next, the lead frame 13 is fixed to the lower surface of the circuit board 11 formed as described above using an adhesive 14. In this case, lead frame 13
Although the through holes 15 are formed in advance, they may be formed before the steps described below. After forming through holes 15 in the circuit board 11 and adhesive 14 corresponding to the through holes 15 on the lead frame 13 side,
A conductor layer 16 is formed in each through-hole 15 by plating the circuit board 11 and the lead frame 13 at the required locations other than the required locations for conduction, and by applying copper plating to the required locations for conduction. Finally, the plating resist that is no longer needed is peeled off to form a predetermined semiconductor mounting substrate 10.

Note that, as shown in FIGS. 1 to 4, for each semiconductor mounting substrate 10 formed in this way,
Each semiconductor element 20 is connected to the conductor circuit 12 of the circuit board 11.
Each semiconductor element 20 and the conductor circuit 12 are electrically connected to each other by a bonding wire 21. In this case, in the semiconductor mounting substrate 10 according to the present invention, it is not necessary to directly connect one end of the bonding wire 21 to the lead frame 13 side. This is because electrical conduction with the lead frame 13 is performed through each through hole 15. After that, for this semiconductor mounting board 10, the necessary locations (locations indicated by dotted lines in each drawing)
is molded with sealing resin 22.

(Actions of the Invention) By adopting the above-described measures, the present invention has the following effects.

That is, first, the electrical connection by the bonding wire 21 is made by connecting the conductor circuit 12 on the circuit board 11.
and is performed only between each semiconductor element 20. In other words, the conductor circuit 12 on the circuit board 11
The lead frame 13 and the lead frame 13 are connected through the conductor layer 16 in each through hole 15, and there is no direct electrical connection between the lead frame 13 and each semiconductor element 20 by the bonding wire 21. . Furthermore, by forming the circuit board 11 on the conductor circuit 12 into a pattern necessary for electrical connection of each semiconductor element 20, each divided lead and each semiconductor element 20 can be connected to each other through the through hole 1.
5, a separate and independent circuit is formed through the conductor layer 16 in the conductor layer 16.

Therefore, in this semiconductor mounting substrate 10, silver plating or the like for bonding connection is not applied on the lead frame 13.
Therefore, the problems that occur in the conventional semiconductor mounting board shown in FIG. 6, such as disconnection of bonding wires due to deterioration of the silver plating on the lead frame 33 side, do not occur. be.

Moreover, in this semiconductor mounting board 10,
If there is no need to connect the conductor circuit 12 on the circuit board 11 and the lead frame 13 with the bonding wire 21, it is necessary to actively form a so-called bonding pad or bonding terminal on the edge of the circuit board 11. There is no. Since it is not necessary to provide bonding pads or bonding terminals at the edge of the circuit board 11 in this way, there are no restrictions when forming the conductor circuit 12 on the circuit board 11, and a large number of semiconductor elements 20 can be mounted. When the conductor circuit 12 is constructed as follows, it has become possible to sufficiently increase the density of the conductor circuit 12.

Of course, even if a curved surface is formed at the edge of the circuit board 11 by shearing the external shape of the circuit board 11 on which the conductive circuit 12 is formed, the semiconductor mounting board 10 according to the present invention may be Since bonding is not performed at the edge, the tip 38 of the jig, as in the conventional semiconductor mounting board shown in FIG. 7, moves to the left in the figure and the bonding wire 35
It goes without saying that accidents such as not being able to perform accurate bonding or having to remove the wire 35 that has been painstakingly bonded do not occur.

(Example) Next, the semiconductor mounting substrate 10 according to the present invention is
Embodiments will be described in detail according to the embodiments shown in the drawings.

Embodiment 1 FIG. 1 shows a vertical cross-sectional view of a semiconductor mounting substrate 10 according to a first embodiment of the present invention. A circuit board 11 is fixed. A conductor circuit 12 is formed on the upper surface of the circuit board 11, and a plurality of semiconductor elements 20 are mounted at predetermined positions on the conductor circuit 12. Each semiconductor element 20 and the conductive circuit 12 are electrically connected via bonding wires 21.

Moreover, in this semiconductor mounting board 10,
A through hole 15 passing through the circuit board 11, adhesive 14, and lead frame 13 is formed at a predetermined position, and a conductor layer 16 is formed within this through hole 15. Thereby, a predetermined portion of the conductor circuit 12 on the circuit board 11 and a predetermined portion of the lead frame 13 are electrically connected via the conductor layer 16 in the through hole 15.

In FIG. 1, the formation position of each through hole 15 is set to the edge of the circuit board 11, but of course the formation position of each through hole 15 is not limited to this, and as shown in FIG. It may be located at the center of the circuit board 11.

Note that the semiconductor mounting substrate 1 formed in this manner
0, after mounting a plurality of semiconductor elements 20 and connecting them to the conductor circuit 12 with the bonding wire 21 as described above, the sealing resin 22 shown by the dotted line in FIG. It will be sealed.

Embodiment 2 FIGS. 3 and 4 show a semiconductor mounting substrate 10 according to a second embodiment of the present invention. The difference between this second embodiment and the first embodiment described above is that a recess 17 is formed in the portion of the lead frame 13 to which the circuit board 11 is fixed. This recess 17 is located on the circuit board 11 relative to the lead frame 13.
This is to facilitate positioning of the circuit board 11, the adhesive 14, and the lead frame 13, and to shorten the length of the through hole 15 that passes through the circuit board 11, adhesive 14, and lead frame 13.

Since the other configurations are the same as those of the first embodiment, the same members are given the same reference numerals and detailed explanation thereof will be omitted.

(Effects of the Invention) As described in detail above, in the present invention, as exemplified in the above embodiment, "the circuit board 11 and the lead frame 13 are provided with a through hole 15 passing through them, and the through hole 15 to directly electrically connect a part of the conductor circuit 12 on the circuit board 11 and a part of the lead frame 13. , not only can bonding be performed reliably and easily, but also the conductor circuit on the circuit board can be simplified, and it can be manufactured using conventional machines and equipment as is. Therefore, it is possible to provide a semiconductor mounting substrate 10 having the following configuration.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views of a semiconductor mounting board according to the first embodiment of the present invention, and FIG.
Each of FIG. 4 and FIG. 4 is a longitudinal cross-sectional view of a semiconductor mounting board according to a second embodiment of the present invention. Further, FIG. 5 is a partial vertical cross-sectional view showing steps for explaining the method of manufacturing a semiconductor mounting substrate according to the present invention. 6 is a vertical sectional view showing a conventional semiconductor mounting board, and FIG. 7 is a partially enlarged sectional view taken along the line - in FIG. 6. Explanation of symbols, 10... Semiconductor mounting board, 11
... Circuit board, 12 ... Conductor circuit, 13 ... Lead frame, 14 ... Adhesive, 15 ... Through hole,
16... Conductor layer, 17... Recess, 20... Semiconductor element, 21... Bonding wire, 22...
Sealing resin.

Claims (1)

[Scope of Claims] 1. A semiconductor mounting comprising a circuit board on which a conductive circuit is formed and a semiconductor element is to be mounted, and a lead frame that is integrally fixed to this circuit board to ensure continuity with the outside. In the circuit board and the lead frame, a through hole is provided in the circuit board and the lead frame, and a conductor layer is formed in the through hole so that a part of the conductor circuit on the circuit board and a part of the lead frame are formed. A semiconductor mounting board characterized by having a direct electrical connection between the two. 2. The semiconductor mounting board according to claim 1, wherein the through hole is formed between a plurality of semiconductor elements to be mounted on the circuit board. 3. A recess in which the circuit board is housed is formed in a part of the lead frame.
A substrate for mounting semiconductors as described in .