Semiconductor device and method of manufacturing such device

Active solid-state devices (e.g. – transistors – solid-state diode – Lead frame – On insulating carrier other than a printed circuit board

Reexamination Certificate

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Details

C257S781000, C257S778000, C257S650000, C257S692000, C257S784000, C257S701000, C257S780000, C257S787000

Reexamination Certificate

active

06489667

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates, in general, to semiconductor devices and a method of manufacturing such devices and, more particularly, to a semiconductor device having a substrate on one surface of a semiconductor chip, the substrate extending on the chip so as to exceed the outside edge of the chip, thus carrying an increased number of solder balls or signal input/output terminals on the device and being almost free from being bent, and effectively dissipating heat from the chip to the atmosphere, the invention also relating to a method of manufacturing such a semiconductor device.
DESCRIPTION OF THE PRIOR ART
As is well known to those skilled in the art, a semiconductor device is used for mounting a semiconductor chip on a mother board in addition to intermediating input/output signals between the chip and the mother board. In accordance with the recent trend of compactness, lightness, thinness and smallness of semiconductor chips, it has been necessary to make the semiconductor device compact, light, thin and small.
FIG. 1
shows a conventional semiconductor device
100
′. In the drawing, the semiconductor device
100
′ is shown while being inverted for ease of description.
As shown in the drawing, the conventional semiconductor device
100
′ comprises a semiconductor chip
40
′, having a plurality of signal input/output pads or edge pads
41
′ on its upper edge. A substrate
10
′ is formed on the upper surface of chip
40
as follows. A polyimide layer
12
′ is attached to the upper surface of the chip
40
′ with an adhesive layer
21
′ being interposed between the chip
40
′ and the polyimide layer
12
′. The above substrate
10
′ also comprises a plurality of circuit patterns formed on the polyimide layer
12
′. Each of the circuit patterns consists of a solder ball land
15
′. A connector
14
′ extends from the solder ball land
15
′ and has a lead
13
′ at its outside end, and is connected to an associated signal input/output pad
41
′ of the chip
40
′ at the lead
13
′ using an electric connecting means
50
′. A cover coat
16
′ is coated on both the connectors
14
′ of the above circuit patterns and the upper surface of the polyimide layer
12
′. In order to protect the pads
41
′ of the chip
40
′, the electric connecting means
50
′ and the leads
13
′ from the atmospheric environment, the upper edge of the chip
40
′ is packaged using a packaging material, thus forming a packaging part
60
′. A solder ball
70
′ is welded to each of the solder ball lands
15
′ and is used for mounting the semiconductor device
100
′ on a mother board.
Such semiconductor devices
100
′ may be produced as follows. In a first conventional process, a plurality of semiconductor chips are primarily attached to the lower surface of a wafer-shaped substrate using an adhesive layer, thus performing a wafer lamination step. Thereafter, an electric connection step is performed. In the electric connection step, each signal input/output pad of each of the semiconductor chips is connected to an associated lead of the circuit patterns of the substrate using an electric connecting means. The electric connection step is followed by a packaging step wherein the upper edge of each of the semiconductor chips is covered with a packaging part so as to protect the electric connection part, comprising the signal input/output pads, the electric connecting means and the leads, from the atmospheric environment. Thereafter, a solder ball welding step, wherein a plurality of solder balls are welded to the solder ball lands of the substrate, is performed. A singulation step follows the solder ball welding step. In the singulation step, the wafer, with the substrate, is divided into a plurality of semiconductor devices.
Alternatively, the semiconductor devices may be produced through a second process. In the second process, a plurality of semiconductor chips are bonded to a rectangular or regular square substrate strip prior to performing the same electric connection step, packaging step, solder ball welding step and singulation step as that described for the first process.
In recent years, it is necessary to carry an increased number of signal input/output pads on a semiconductor chip in accordance with a development in the semiconductor chip integration technology. Therefore, it is also necessary to increase the number of solder balls formed on each semiconductor device. However, since the conventional substrate is formed on a limited area of one surface of a semiconductor chip as described above, the area of the substrate is smaller than that of the chip. This limits both the number of circuit patterns and the number of solder balls formed on each substrate.
In order to overcome the above-mentioned problems, the substrate may extend in a way such that it exceeds the outside edge of the chip. However, since the substrate is made of a flexible material, the enlarged substrate is partially and easily bent at a portion outside the edge of the chip. When a solder ball is carried on the portion of the substrate outside the edge of the chip, the substrate regrettably fails to firmly or effectively support the solder ball on that portion.
Another problem, experienced in the conventional semiconductor device, resides in that the device fails to effectively dissipate heat from the semiconductor chip into the atmosphere during an operation of the device. That is, in accordance with the recent trend of high integration degree and high operational frequency of semiconductor chips, each semiconductor chip emits a large quantity of heat during an operation of the device. However, the conventional semiconductor device does not have any structure designed to effectively dissipate the heat to the atmosphere, thus being reduced in its electric performance and causing an operational error of the chip.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a semiconductor device, of which the substrate extends on one surface of a semiconductor chip so as to exceed the outside edge of the chip and has an area larger than that of the chip, thus effectively carrying an increased number of circuit patterns and solder balls or signal input/output terminals on the device.
Another object of the present invention is to provide a semiconductor device, of which the electric connection part, comprising the bond fingers of the substrate and the signal input/output pads of the chip, is primarily packaged with a packaging material, thus being prevented from unexpected separation during a process of manufacturing the device, and which is secondarily packaged with a packaging material so as to enhance the bonding strength between the chip and the substrate, thus preventing an undesirable bending of the substrate and firmly supporting the solder balls carried on the substrate, and increasing the bonding strength at the junction between the parts of the device.
A further object of the present invention is to provide a semiconductor device which more effectively and quickly dissipates heat from the semiconductor chip into the atmosphere, thus being almost free from a reduction in its electric performance and being almost free from any operational error of the chip.
Still another of the present invention is to provide a method of manufacturing the above-mentioned semiconductor device.
In order to accomplish the above objects, an embodiment of the present invention provides a semiconductor device, comprising: a semiconductor chip having a plurality of signal input/output pads on one surface thereof; a substrate having a plurality of regularly arranged circuit patterns and an area larger than that of the semiconductor chip, each of the circuit patterns consisting of a solder ball land and a bo

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