Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package
Reexamination Certificate
1999-09-07
2001-03-06
Abraham, Fetsum (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
C257S676000, C257S684000, C257S688000, C257S693000
Reexamination Certificate
active
06198161
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor device, in particular, to a semiconductor device of which a semiconductor package is flexibly mounted and electrically connected to a wiring substrate.
2. Description of the Related Art
To mount a semiconductor package on a wiring substrate as a motherboard, a solder layer composed of for example Sn—Pb should be formed on at least one of the semiconductor package side and the wiring substrate side by a plating method, a printing method, or the like. Thereafter, the solder layer should be heated and melted (re-flowed). With the melted solder as an adhesive agent, the semiconductor package and the wiring substrate are mechanically and electrically connected.
However, such a mounting method for a semiconductor package has the following problems. To heat and melt the solder layer, since an expensive unit referred to as re-flow furnace is used, the cost of the fabrication facility is high. In addition, when solder is re-flowed, since the semiconductor package is exposed to a high temperature environment, the quality of the resultant semiconductor device against high temperature should be assured. Thus, a heat resisting material that is expensive should be used. Moreover, since the solder contains lead that is harmful to human bodies, it should be used and discharged with special attention against protection of environmental contamination.
SUMMARY OF THE INVENTION
The present invention is achieved to remedy the disadvantages described above. The invention aims to provide a semiconductor device that has mounting reliability equal to or higher than a conventional one without need to use an expensive facility such as a re-flow furnace and that allows the material cost and the number of fabrication steps to reduce and decrease.
The present invention is a semiconductor device, comprising a semiconductor package having a first wiring substrate having a first region and a second region, a first connecting terminal formed on the first region, a second connecting terminal formed on the second region and connected to the first connecting terminal, and a semiconductor element mounted in the first region of the wiring substrate and connected to the first connecting terminal, a second wiring substrate having an external connecting terminal disposed opposite to the second connecting terminal of the wiring substrate of the semiconductor package, and connecting means for connecting the second connecting terminal of the first wiring substrate and the external connecting terminal of the second wiring substrate, the connecting means having a protrusion electrode terminal at least whose surface is coated with a conductor layer, and a receiving terminal portion at least whose surface is coated with a conductor layer, the receiving terminal portion being detachable fitted and electrically connected to the protrusion electrode terminal.
According to one aspect of the present invention, the first substrate used in the semiconductor package is for example a wiring substrate of which a wiring layer composed of for example Cu, Cu alloy, or aluminum is formed on at least one main surface (namely, one surface or two surfaces) of an insulation substrate (such as a glass cloth—epoxy resin impregnated substrate) or an insulation resin film (such as a polyimide resin film or a polyethylene terephthalate film (PET film)). The wiring layer contains a first connecting terminal, a second connecting terminal, and a wiring portion. The first connecting terminal is connected to the semiconductor element. The second connecting terminal is connected to a second wiring substrate (that will be described later). The wiring portion connects the first connecting terminal and the second connecting terminal.
The second wiring substrate that is a mother board on which the semiconductor package is disposed or mounted is a rigid wiring substrate having a wiring layer formed on at least one main surface of an insulation substrate such as a glass cloth—resin impregnated substrate or a ceramic substrate. The wiring layer of the second wiring substrate contains an external connecting terminal (third connecting terminal) connected to the semiconductor package.
According to one aspect of the present invention, the second connecting terminal of the first wiring substrate, which is used in the semiconductor package, and the external connecting terminal (third connecting terminal) of the second wiring substrate (mounting substrate) are mechanically connected with a protrusion electrode terminal disposed on one of the second and third connecting terminals and a receiving terminal portion disposed on the other connecting terminal. The protrusion electrode terminal and the receiving terminal portion are detachably fitted. In addition, since the conductor layers on the surfaces of the protrusion electrode terminal and the receiving terminal portion contact each other, their electrical connections are secured.
Such a connecting means is accomplished by a combination of a protrusion electrode terminal and a receiving terminal portion. Thus, the protrusion electrode terminal may be disposed on either the first wiring substrate side or the second wiring substrate side. The receiving terminal portion is for example an aggregated electrode layer having a plurality of fiber electrodes that are bound or tangled.
The receiving terminal portion may have a protrusion receiving electrode terminal. In addition, the shape of the protrusion electrode terminal may be almost the same as the shape of the receiving electrode terminal. In other words, the protrusion electrode terminal may have a cylinder portion (for example, a circular cone portion) and a disk portion formed at an edge thereof. The receiving terminal portion may have a receiving electrode terminal in the same shape as the protrusion electrode terminal. In this case, with the protrusion electrode terminal and the receiving electrode terminal that fit or contact each other, their mechanical/electrical connections are secured.
The receiving terminal portion may be a multilayered electrode portion having a plurality of aggregated electrode layers that are piled up in the direction of the thickness thereof. When the aggregated electrode layers of the multilayered electrode portion fit respective protrusion electrode terminals that have different heights, the multilayered electrode portion is three-dimensional connections with a plurality of protrusion electrode terminals having different heights.
In the semiconductor device according to the present invention, with a protrusion electrode terminal disposed at one of an external connecting terminal (second connecting terminal) of a semiconductor package and an external connecting terminal of a second wiring substrate (motherboard) and a receiving terminal portion disposed at the other connecting terminal that detachably fit each other, they are mechanically connected with predetermined strength. In addition, their electrical connections are properly performed. Thus, they are connected without need to have a heating step at high temperature. In other words, they can be connected at room temperature. The semiconductor package can be repaired at room temperature.
In a conventional semiconductor device of which a semiconductor package is connected to a wiring substrate through a solder layer, the solder joint portion deteriorates with a temperature cycle. In contrast, according to the present invention, since a semiconductor package and a wiring substrate are connected with sufficient flexibility without need to use solder, the stress concentration to the connecting portion due to a periodic heat load or the like is suppressed. Thus, the connecting portion does not almost deteriorate. In addition, since solder containing lead harmful to human bodies is not used as a structural material of the semiconductor device, the present invention is effective from a view point of protection of environmental contamination.
These and other objects, features and advantage
Abraham Fetsum
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
LandOfFree
Semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2522915