Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1998-12-03
2001-10-02
Gaffin, Jeffrey (Department: 2841)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S748000, C361S750000, C361S751000, C361S813000, C174S254000, C174S255000, C174S260000, C174S261000, C257S701000, C257S690000, C257S673000, C438S110000, C438S112000
Reexamination Certificate
active
06297964
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, a method of fabricating the same, a film carrier tape, a circuit board, and an electronic apparatus.
2. Description of Related Art
In the pursuit of microminiaturization of semiconductor devices, a bare chip mounting arrangement is regarded as an ideal form of assembling. However, since quality assurance of a bare chip and the handling thereof are practically difficult, it in assembled in a package in semiconductor device fabrication. As one of package forms meeting multi-terminal requirements, a ball grid array (BGA) type of package has been developed recently. On a substrate of the BGA type package, external terminal bumps are arranged in an area array to permit surface mounting.
A flexible package substrate is used in one kind of BGA type package. In fabrication of such a kind of BGA type package, a tape automated bonding (TAB) technique is practiced since it satisfies a need for mounting a semiconductor chip having arrow-pitch pads and allows a continuous flow of production.
In Japanese Patent Application Laid-Open No. 8-31869, for example, there is disclosed a method of fabricating a BGA type package using a film carrier tape. On the film carrier tape, individual leads are formed for each package, i.e., not all the leads are formed to have conductivity. It is therefore necessary to provide electroplating on individual leads for each package, resulting in a burdensome step in fabrication. Even if all the leads are formed to have conductivity on the film carrier tape, the end face of each lead is exposed after the film carrier tape is punched out, making it necessary to take any special measures for preventing leakage on insulation, degradation of moisture resistance reliability, etc.
SUMMARY OF THE INVENTION
The present invention obviates the abovementioned disadvantages, and an object thereof is to provide a semiconductor device which can prevent degradation of reliability even if the end face of a lead is exposed on the outline edge of a film, a method of its fabrication, a film carrier tape, a circuit board and electronic apparatus.
(1) According to a first aspect of the present invention. there is provided a semiconductor device comprising:
an insulating film having a device hole;
a plurality of external electrodes formed on the insulating film;
a plurality of first leads having end faces exposed on an outline edge of the insulating film, each of the first leads being electroplated and connected with one of the external electrodes, and the insulating film being outlined to have a cut in a region including each of the exposed end faces of the first leads;
a plurality of second leads having end portions protruding into the device hole, each of the second leads being electroplated and connected with one of the external electrodes; and
a semiconductor element connected with the end portions of the second leads in the device hole.
In the semiconductor device of the first aspect of the present invention, surface mounting can be made using the plural external electrodes formed on the insulating film. The leads are electroplated. Although the end faces of the first leads are exposed on an outline edge of the insulating film, the insulating film is outlined to have a cut in a region including each of the exposed end faces of the first leads. Therefore, even if the outside edges of the insulating film are held with fingers, the end faces of the first leads do not come into contact with fingers, thus preventing degradation of moisture resistance reliability due to accidental intrusion of moisture into the inside part.
(2) The first leads may be formed so that the exposed end faces are gathered at a plurality of points.
Since the first leads are disposed to circumvent the external electrodes, the first leads are formed closely on predetermined regions in most cases. Where the exposed end faces of the first leads are gathered at certain points, the insulating film can be cut at respective regions corresponding to the gathering of the end faces of the first leads. Thus, the number of cuts can be reduced.
(3) According to a second aspect of the present invention. there is provided a semiconductor device comprising:
an insulating film having a device hole;
a plurality of external electrodes formed on the insulating film;
a plurality of first leads having end faces exposed on an outline edge of the insulating film, each of the first leads being electroplated and connected with one of the external electrodes, and the first leads being formed so that at least the exposed end faces are arranged in a mutually dispersed fashion;
a plurality of second leads having end portions protruding into the device hole, each of the second leads being electroplated and connected with one of the external electrodes; and
a semiconductor element connected with the end portions of the second leads in the device hole.
In the semiconductor device of the second aspect of the present invention. Surface mounting can be made using the plural external electrodes formed on the insulating film. The leads are electroplated. Although the end faces of the first leads are exposed on the outline edge of the insulating film, the exposed end faces are arranged in a mutually dispersed fashion. Therefore, since adjacent end faces are spaced widely, an electric field between them can be reduced. Reduction of the electric field makes leakage unapt to occur even if moisture adheres to the outline edge of the insulating film thereby improving reliability of the semiconductor device.
(4) The first leads may be arranged with approximately equal spacing.
In this way, the exposed end faces of the first leads can be arranged in mutually dispersed relationship.
(5) According to a third aspect of the present invention, there is provided a method of making a semiconductor device, comprising steps of:
providing a film carrier tape having,
a plurality of device holes,
a plurality of external electrodes,
a plurality of leads having the end portions protruding into the device hole, each of the leads running through one of the external electrodes,
a plating lead connected with all the leads, the leads being electroplated via the plating lead, and
a semiconductor element located in each of the device holes and connected with ones of the end portions of the leads; and
stamping out from the film carrier tape a shape having a cut in a region in which the leads are formed.
In this aspect of the present invention, each semiconductor element is mounted on the film carrier tape having the external electrodes and leads, and then the film carrier tape is punched out for semiconductor device fabrication. At this process of semiconductor device fabrication, the film carrier tape is punched out so that it is configured to have a cut in a lead-formed region. A semiconductor device thus fabricated has a cut in a region including each of the exposed end faces of the leads. Therefore, even if the semiconductor device is held with fingers, the end faces of the leads do not come into contact with fingers, thus preventing degradation of moisture resistance reliability due to accidental intrusion of moisture into the inside part.
(6) The leads may be formed to gather at a plurality of points.
Since the leads are disposed to circumvent the external electrodes, the loads are formed closely on predetermined regions in most cases. The number of cuts can be reduced in such a manner that the insulating film is cut at regions corresponding to the gathering of the leads
(7) According to a fourth aspect of the present invention, there is provided a film carrier tape comprising:
portions defining a plurality of device holes;
a plurality of external electrodes;
a plurality of leads having end portions protruding into the device holes, each of these leads running through one of the external electrodes; and
a plating lead connected with all the leads;
wherein the leads are electroplated via the plating leads; and are formed to be arranged in a mutually dispersed fa
Foster David
Gaffin Jeffrey
Oliff & Berridg,e PLC
Seiko Epson Corporation
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