JPH0824151B2 - Semiconductor mounting board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a package substrate such as a pin grid array and a hybrid IC substrate as a semiconductor mounting substrate that requires high-density mounting.

(Prior Art) In a semiconductor mounting substrate, a semiconductor element is mounted and fixed on the mounting portion, and the semiconductor element and a conductor circuit formed on the substrate are electrically connected using a bonding wire or the like. And is used as a semiconductor device. By the way, the semiconductor element mounted on this substrate, the conductor circuit and the bonding wire formed on the substrate are very susceptible to external impacts, moisture in the air, etc. It must be protected by various methods.

Such protection of semiconductor elements and the like is usually performed as follows. That is, the sealing resin is dropped onto a portion requiring protection (usually in the vicinity of the semiconductor element) or a portion requiring protection is covered with a metal cap. In particular, in the case of covering with a metal cap, the semiconductor mounting substrate and the metal cap are joined via an adhesive layer. The metal cap used in this case is made of a material such as copper alloy or aluminum, and in order to ensure the corrosion resistance of the cap and the insulation with the substrate, the surface of the metal cap is oxidized. A film or resin film is formed.

Conventionally, as a sealing structure using a metal cap,
It becomes as shown in FIG. That is, in the conventional external processing of the semiconductor mounting board, the end portion (23) of the plating lead wire, which is a part of the conductor circuit (24), is formed on the outer peripheral edge portion (29) on the semiconductor element mounting surface side. Is left exposed on the outer periphery of. This is because the plating lead wire is necessary as a lead wire that promotes electrical connection for plating the conductor circuit (24) of the semiconductor mounting board.
This is because, as shown in the plan view of the board shown in FIG. 6A and the cross-sectional view of the board shown in FIG. 6, this lead wire for plating is also cut at the same time in the final outer shape processing in the board manufacturing process.

When a sealing structure using a metal cap is adopted for such a semiconductor mounting substrate and the clearance between the outer shape of the substrate and the inner wall of the metal cap is small, a part of the conductor circuit on the substrate is formed. In some cases, the plating lead wire and the inner wall of the metal cap come into contact with each other to cause an electrical short circuit or electric discharge breakdown, which may cause the semiconductor device to stop functioning.

(Problems to be Solved by the Invention) The present invention has been made in view of the above circumstances, and the problem to be solved is that a conductor circuit left on the outer peripheral edge of the semiconductor mounting substrate ( It is too close to the end of the lead wire for plating) and the metal cap.

And, the object of the present invention is that FIGS.
As shown in the figure, a part of the outer peripheral edge of the semiconductor mounting board is positively removed together with the end of the plating lead wire that is a part of the conductor circuit formed on the surface of the semiconductor mounting board. To provide a semiconductor mounting substrate capable of completely preventing an electrical short circuit or the like that deteriorates the function as a semiconductor device by increasing a gap between an end of a circuit (plating lead wire) and a metal cap. It is in.

(Means for Solving the Problems) In order to solve the above problems, the means adopted by the present invention is, “In a semiconductor mounting substrate for sealing a mounted semiconductor element with a metal cap, A part of the outer peripheral edge portion of the substrate is chamfered or stepped obliquely together with the conductor circuit formed on the surface thereof to remove the end portion of the conductor circuit on the semiconductor mounting substrate, and The semiconductor mounting substrate is characterized in that a gap is formed between the metal caps. "

Hereinafter, this means will be described in detail according to a specific example shown in the drawings.

FIG. 1 is a perspective view showing an example of a semiconductor mounting substrate (1) according to the present invention, which is generally called a pin grid array. This semiconductor mounting substrate (1) has a semiconductor element mounting portion and a conductor circuit (4) formed on the upper surface of a substrate made of a resin material, and in the semiconductor mounting substrate (1), the outer shape of the substrate. By chamfering the peripheral portion, the end (3) of the conductor circuit (4) (plating lead wire) is removed together with a part of the substrate (1) to form a chamfered portion (10). There is. As a result, in this semiconductor mounting substrate (1), as shown in FIG. 2, the lead wire for plating necessary when forming the conductor circuit (4) extending to the outer peripheral edge of the substrate has its end. It is cut at the portion (3), and the end portion (3) is located inside the outer shape of the substrate.

The chamfering of the substrate may be performed after the outer shape of the substrate, but as shown in the plan view of the substrate of FIG. 2A and the substrate sectional view of FIG. A printed wiring board in which a large number of semiconductor mounting boards are continuously arranged in a circular pattern is formed on the contour line that is the outer shape of each semiconductor mounting board, so that the plating lead wire and the chamfered portion of the board ( A method may be used in which after removing the portion to be 10) at the same time, the outer shape is cut and separated into the respective semiconductor mounting substrates (1).

Conductor circuit on outer peripheral edge of semiconductor mounting board (4)
When removing the (plating lead wire) and a part of the substrate to form the chamfered portion (10) as described above,
In addition to the diagonal chamfering process as shown in FIGS. 3 and 4, a method of removing by forming the curved surface portion (11) by the curved surface processing as shown in FIG. 4 and the method as shown in FIG. By forming a step (12) by cutting, the plating lead wire and a part of the substrate are deleted, and the end (3) of the plating lead wire is retracted to the inside of the substrate. Wire end (3) and metal cap (2)
It is also possible to adopt a method of preventing the contact with the inner wall of the metal and improving the insulation with the metal cap (2).

In FIG. 3, a semiconductor element (5) is mounted on a semiconductor mounting substrate (1) according to the present invention, and this semiconductor mounting substrate (5) is mounted.
There is shown a vertical cross-sectional view of the substrate (1) covered with a metal cap (2) to cover the substrate. This semiconductor mounting substrate (1) is a substrate made of a resin material on which a semiconductor element mounting portion and a conductor circuit (4) for external output are formed, and a chamfering process is performed on the outer periphery of the substrate (1). After forming the chamfered part (10), the semiconductor element (5) is mounted,
This is a structure in which a conductor circuit (4) on a substrate (1) and a semiconductor element (5) are connected by a bonding wire (6) and then sealed by a metal cap (2).

(Operation of the Invention) A part of the outer peripheral edge portion of the substrate (1) is extended to the outer peripheral edge portion by chamfering the plating lead wire which is a part of the conductor circuit (4) on the surface thereof. It has become possible to retract the end portion (3) of the plating lead wire that had been used, to prevent contact between the end portion (3) of this plating lead wire and the inner wall of the metal cap (2), and to perform the recessed plating. The exposed portion of the end (3) of the lead wire for use is covered with the adhesive layer (7) with the metal cap (2), so that the insulation between the conductor circuit (4) and the metal cap (2) is further improved. To do.

(Example) Example 1 As shown in FIG. 3, for a plastic pin grid array in which a semiconductor element mounting portion and a conductor circuit (4) were formed from a glass-epoxy substrate and conductor pins (8) were mounted as external output terminals. A substrate (1) is formed, the outer peripheral edge of the substrate (1) is chamfered, and the end (3) of the plating lead wire is removed together with a part of the substrate (1) to remove the chamfered portion (10).
Was formed. After mounting and mounting the semiconductor element on the semiconductor element mounting portion of the substrate (1), the semiconductor element was sealed with the metal cap (2). In this case, the end portion (3) of the lead wire for plating, which was exposed at the peripheral portion of the outer shape of the substrate (1), was recessed from the outer shape of the substrate (1) and was exposed at the adhesive layer (7). The end portion (3) of the plating lead wire is covered with a metal cap (2).
The electrical insulation between the end part (3) of the lead wire for plating and the end part (3) was improved.

Example 2 As shown in FIG. 4, a plastic pin grid array substrate (1) in which a semiconductor element mounting portion and a conductor circuit (4) were formed of a glass-epoxy substrate and conductor pins (8) were mounted as external output terminals. Then, the outer peripheral edge of the substrate (1) was subjected to curved surface processing, and the end portion (3) of the lead wire for plating was removed together with a part of the substrate (1) to form the curved surface portion (11). A semiconductor element was mounted relative to the substrate (11) and then sealed with a metal cap (2). In this case, the end portion (3) of the lead wire for plating, which was exposed at the peripheral portion of the outer shape of the substrate (1), was recessed from the outer shape of the substrate (1) and was exposed at the adhesive layer (7). End of plating lead wire (3)
Was coated to improve the electrical insulation between the metal cap (2) and the end portion (3) of the plating lead wire.

Embodiment 3 As shown in FIG. 5, a plastic pin grid array substrate (1) on which a semiconductor element mounting portion and a conductor circuit (4) are formed of a glass-epoxy substrate and conductor pins (8) are mounted as external output terminals. Then, the outer peripheral edge of the substrate (1) was subjected to counterboring, and the end (3) of the plating lead wire was removed together with a part of the substrate (1) to form a step (12). After mounting and mounting the conductor element on this substrate (1), it was sealed with a metal cap (2). In this case, the end portion (3) of the lead wire for plating, which was exposed at the peripheral portion of the outer shape of the substrate (1), was recessed from the outer shape of the substrate (1) and was exposed at the adhesive layer (7). End of plating lead wire (3)
Was coated to improve the electrical insulation between the metal cap (2) and the end (3) of the lead wire for plating.

(Structure of the Invention) According to the present invention, the semiconductor element (5) is mounted on the substrate (1) on which the conductor circuit (4) is formed, and the semiconductor element (5) is connected by a bonding wire (6) or the like. In the semiconductor mounting substrate (1), even if the metal cap (2) is joined for the purpose of protecting the semiconductor element, the conductor circuit (4) on the outer peripheral edge of the substrate (1).
A sufficient gap can be secured between the end portion (3) of the (plating lead wire) and the metal cap (2), and further, the bonding formed on the joint surface between the substrate (1) and the metal cap (2). It can be completely insulated by the layer (7).

As a result, it is possible to provide a semiconductor mounting substrate that can completely prevent an electrical short circuit or the like that deteriorates the function of the semiconductor device mounting the semiconductor element.

[Brief description of drawings]

FIG. 1 is a perspective view of a semiconductor mounting substrate according to the present invention, and FIG.
(A) and (b) of the figure are partial plan views and sectional views showing a state in which the semiconductor mounting substrate is formed, and FIG. 3 is a state in which a metal cap is covered on the semiconductor mounting substrate shown in FIG. FIG. 4 is an enlarged cross-sectional view showing FIG. 4 and FIG. 5 is a cross-sectional view corresponding to FIG. 3 showing another embodiment of the present invention. FIG. 6 shows a conventional semiconductor mounting substrate with a metal cap covered. It is sectional drawing shown. Explanation of symbols 1 …… Semiconductor mounting board, 2 …… Metal cap, 3 ……
End of plating lead wire, 4 ... Conductor circuit, 5 ... Semiconductor element, 6 ... Bonding wire, 7 ... Adhesive layer,
8 ... Conductor pin, 10 ... Chamfer part, 11 ... Curved part, 12 ...
… Steps.

Claims (1)

[Claims] 1. A semiconductor mounting substrate in which a mounted semiconductor element is sealed with a metal cap. A part of an outer peripheral edge of the semiconductor mounting substrate is chamfered obliquely with a conductor circuit formed on the surface of the semiconductor mounting substrate. A semiconductor mounting board, characterized in that a gap is formed between an end portion of a conductor circuit on the semiconductor mounting board and the metal cap by processing and deleting the stepped shape.