Active solid-state devices (e.g. – transistors – solid-state diode – Combined with electrical contact or lead – Chip mounted on chip
Reexamination Certificate
1999-07-26
2001-08-21
Loke, Steven (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Combined with electrical contact or lead
Chip mounted on chip
C257S778000, C257S783000, C257S723000, C257S781000, C257S702000, C257S730000, C257S680000, C257S787000
Reexamination Certificate
active
06278190
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device with semiconductor elements multilayered.
2. Description of the Related Art
FIG. 5
is a sectional view of a conventional semiconductor device with semiconductor elements multilayered, as described in e.g. JP-A-10-242,381. In
FIG. 5
, reference numerals
1
and
2
denote a semiconductor element, respectively, and reference numeral
3
denotes one of bumps formed on the semiconductor element
1
. The semiconductor element
1
is electrically connected to the semiconductor element
2
through an adhesive layer containing conductive particles. The adhesive layer
4
is a single layer of a single material. The adhesive layer
4
is connected to external leads
5
each of which is shaped in a Gull-Wing to constitute an external terminal. Reference numeral
6
denotes sealing resin which forms an external shape sealing the entire periphery of the semiconductor elements
1
and
2
and a connecting portion between them and the external leads
5
. In this way, a semiconductor device with the plurality of semiconductor elements is constituted.
Now referring to
FIGS. 6A and 6B
, an explanation will be given of the function of the adhesive layer
4
containing the conductive particles.
FIG. 6A
is a view before the semiconductor elements
1
and
2
are bonded, and
FIG. 6B
is a view after they are bonded. Reference numeral
8
denotes one of conductive particles scattered in the adhesive layer
4
. The adhesive layer
4
is essentially an insulator. However, as shown in
FIG. 6B
, the bump
3
provided on the semiconductor element
1
is pressed against the adhesive layer
4
so that the conductive particles
8
are brought into contact with each other between the bump
3
and the electrode
7
formed on the semiconductor element
2
. Thus, electrical conduction is established between the bump
3
and the electrode
7
.
The conventional semiconductor device with a plurality of semiconductor elements multi-layered has a problem that because its entirety is sealed, the package is difficult to be low-profiled and cannot provide high heat dissipation. In addition, the semiconductor device is difficult to be miniaturized because the leads constitute external terminals. Further, since the external terminal is extended through the single adhesive material, it cannot give a high degree of electric freedom where both semiconductor elements
1
and
2
are active elements. Moreover, since the bumps must be formed, it is difficult to manufacture the semiconductor device at low cost.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device with semiconductor elements multi-layered which has advantages of low-profiling, compactness, high dissipation and low cost.
A first aspect of the device is a semiconductor device of the present invention, which comprises: a first semiconductor element having a first circuit plane formed on its surface; a second semiconductor element having a second circuit plane formed oppositely to said first circuit plane and electrically connected to said first semiconductor element within said second circuit plane; a wiring portion surrounding said second semiconductor element and having an external connecting terminal electrically connected to said first semiconductor element; and a sealing material constituting a connecting portion except the back surfaces of said first and second semiconductor elements.
A second aspect of the device is a semiconductor device according to the first aspect, wherein said wiring portion is a frame-like wiring board having an inner periphery more outward than the outer periphery of said second semiconductor element and an outer periphery more inward than the outer periphery of said first semiconductor element.
A third aspect of the device is a semiconductor device according to the first aspect, wherein said wiring portion is a film carrier fixed to the surface of the edge of said first semiconductor element and having a wiring pattern.
A fourth aspect of the device is a semiconductor device according to the third aspect, wherein said sealing material is resin integrally resin-sealing the outsides of said first and second semiconductor elements and a part of said wiring board.
A fifth aspect of the device is a semiconductor device according to the second aspect, wherein said outer connecting terminal is formed in a columnar shape and made of a material not melting in packaging.
A sixth aspect of the device is a semiconductor device according to the second aspect, wherein said outer connecting terminal is formed in a bump or ball shape.
A seventh aspect of the device is a semiconductor device according to the sixth aspect, wherein said outer connecting terminal is a solder ball formed in a through-hole formed so as to expose a portion of a circuit pattern formed on said wiring board.
An eighth aspect of the device is a semiconductor device according to the first aspect, wherein either one of said first semiconductor element and said second semiconductor element has a solder ball for connection and said first and said second semiconductor element are connected through said solder ball.
A ninth aspect of the device is a semiconductor device according to the first aspect, wherein either one of said first semiconductor element and said second semiconductor element has a columnar conductor for connection and are electrically connected to each other through said columnar conductor whereas the periphery of said columnar conductor is sealed by insulating resin.
A tenth aspect of the device is a semiconductor device according to the first aspect, wherein either one of said first semiconductor element and said second semiconductor element has a columnar conductor for connection and are electrically connected to each other through said columnar conductor whereas the periphery of said columnar conductor is sealed by inorganic insulating material.
An eleventh aspect of the device is a semiconductor device according to the first aspect, wherein said first and said second semiconductor element are connected to each other by an anisotropic conductive film.
A twelfth aspect of the device is a semiconductor device according to the first aspect, wherein said semiconductor element consists of plural elements.
A thirteenth aspect of the method is a method of semiconductor device of the present invention, which comprises the steps of: preparing a first semiconductor element having a first circuit plane on its surface; preparing a second semiconductor element having a second circuit plane on its surface and having a smaller size-than that of said first semiconductor element; preparing a wiring board arranged on the periphery of said second semiconductor element and having an external connecting terminal; fixing said first semiconductor element to said wiring board to make an eclectic connection; fixing said second semiconductor element on said first semiconductor element to make an electric connection so that the first and second circuit planes are opposite and electrically connected to each other; and resin-sealing at least the outsides of said first and said second semiconductor element.
In this configuration, a sealing structure with the back of semiconductor elements exposed realizes low-profiling and high heat dissipation. The wiring board and external connecting terminals which are formed facially or circumferentially are adopted, but the lead terminals are not adopted. For this reason, the external shape of the semiconductor device can be easily small-sized. The wiring plate is used and the conductive layer is provided individually on the semiconductor element. This enhances the degree of freedom of wiring.
In accordance with the another aspect of the present invention, preferably, the external connecting terminal is formed in a columnar shape and made of a material not melting in packaging. Therefore, the influence of the thermal stress between the material constituting the semiconductor device and a printe
Loke Steven
McDermott & Will & Emery
Mitsubishi Denki & Kabushiki Kaisha
Parekh Nitin
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