Active solid-state devices (e.g. – transistors – solid-state diode – Non-single crystal – or recrystallized – semiconductor... – Amorphous semiconductor material
Reexamination Certificate
2001-03-28
2002-11-05
Elms, Richard (Department: 2824)
Active solid-state devices (e.g., transistors, solid-state diode
Non-single crystal, or recrystallized, semiconductor...
Amorphous semiconductor material
C257S798000, C257S911000
Reexamination Certificate
active
06476417
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an image-pickup semiconductor device and, more particularly, to an image-pickup semiconductor device packaged with a semiconductor element having a light-receiving element and a lens for picking up an image.
Recently, a cellular phone and a handy PC (a portable personal computer) with a miniature camera incorporated therein have been developed. A cellular phone equipped with a miniature camera, for example, picks an image of the speaker by the miniature camera, converts the image into image data, and transmits the image data to another speaker on the other side of the line. Such a miniature camera like this generally comprises a C-MOS sensor and a lens.
Such a cellular phone and a handy PC are being further miniaturized, and accordingly, the miniature camera used in these apparatus is also required to be smaller. To satisfy the needs like this, a semiconductor device package combining a lens and a C-MOS sensor has been developed.
2. Description of the Related Art
Japanese Laid-Open Pat. App. No. 11-17997 discloses a semiconductor device package having a structure combining a lens for picking an image and a semiconductor chip having a C-MOS sensor. In this semiconductor device package, the semiconductor chip having the C-MOS sensor is mounted on a rigid printed substrate by wire bonding, with a light-receiving surface of the semiconductor chip facing upward. The lens is fixed relative to the printed substrate so as to be placed at a predetermined position above the light-receiving surface of the semiconductor chip. Thus, the conventional semiconductor device package as a miniature camera disclosed in Japanese Laid-Open Pat. App. No. 11-17997 comprises the semiconductor chip mounted on the substrate; and the lens placed above the semiconductor chip.
The above-mentioned semiconductor device package has the following disadvantages originating from the structure thereof.
1) In manufacturing the semiconductor chip having a light-receiving element, the back surface of the semiconductor chip is grinded by a polisher so as to reduce the thickness of the semiconductor chip. For this reason, semiconductor chips on different wafers have various thicknesses. Although a range of the variation in thickness is normally about ±15 &mgr;m, a tolerable range thereof is about ±30 &mgr;m. The varied thickness of the semiconductor chip changes the distance between the light-receiving surface of the semiconductor chip and the lens. In other words, since the lens is placed at a predetermined distance from the surface of the printed substrate, and the light-receiving surface of the semiconductor chip is at a distance equivalent to the thickness of the semiconductor chip from the surface of the printed substrate, the light-receiving surface comes closer to the lens as the thickness of the semiconductor chip is increased, and goes farther from the lens as the thickness of the semiconductor chip is reduced.
The distance between the lens and the light-receiving surface of the semiconductor chip is arranged to be equal to a focal distance of the lens so that light rays transmitting through the lens form an accurate image on the light-receiving surface. Therefore, the above-mentioned varied distance between the lens and the light-receiving surface of the semiconductor chip arouses disadvantages, such as an image out of focus.
2) In mounting the semiconductor chip on the printed substrate, the semiconductor chip is applied and fixed to the surface of the printed substrate by using a dice-applying machine. The dice-applying machine holds the semiconductor chip by sucking the surface (on which the light-receiving element is formed) of the semiconductor chip, and then conveys the semiconductor chip to the printed substrate and places the semiconductor chip thereon. Therefore, the surface of the semiconductor chip is covered by a suction device, preventing a visual recognition of the surface of the semiconductor chip on which the light-receiving element is formed. Instead, the external shape of the semiconductor chip is recognized visually as a basis in adjusting the location of the semiconductor chip on the printed substrate. However, the light-receiving surface and the external shape of the semiconductor chip do not necessarily have a consistent positional relation. In other words, the semiconductor chip, which is formed by dicing a wafer into individual semiconductor chips, has an inconsistent external shape depending on the severing position in dicing. Thereby, the relative position of the light-receiving surface of the semiconductor chip to the external shape of the semiconductor chip is not consistent. Therefore, there are cases where a focal point of the lens does not accurately match the center of the light-receiving surface.
3) Since the semiconductor chip is mounted on the printed substrate by wire bonding, pads for wire bonding have to be provided around the semiconductor chip. Accordingly, the printed substrate needs to have a space to accommodate these pads for wire bonding. This impedes a miniaturization of the semiconductor device package.
4) The semiconductor device package substantially requires a thickness equivalent to a total of the focal distance of the lens and the thickness of the semiconductor chip. However, since the above-mentioned conventional semiconductor device package has the printed substrate placed on the opposite side of the semiconductor chip to the lens, the semiconductor device package actually has a thickness equivalent to a total of the focal distance of the lens and the thickness of the semiconductor chip plus the thickness of the printed substrate. Thus, the thickness of the semiconductor device package is increased by the thickness of the printed substrate.
5) The printed substrate is formed of rigid materials, such as ceramics, or a glass epoxy. Therefore, the printed substrate is not flexible, causing a disadvantage that the semiconductor device package cannot be placed freely when being incorporated into an apparatus. Specifically, there is a restriction that the semiconductor device package has to be directly mounted on a main substrate of a cellular phone or a handy PC, or a flexible wiring substrate has to be provided between the main substrate and the semiconductor device package, in order that the semiconductor device package forming a miniature camera is electrically connected to the main substrate of the cellular phone or the handy PC. This restriction reduces a degree of freedom in designing a body of a cellular phone or a handy PC.
SUMMARY OF THE INVENTION
It is a general object of the present invention to provide an improved and useful image-pickup semiconductor device packaged with a semiconductor element having a light-receiving element and a lens for picking up an image in which device the above-mentioned problems are eliminated.
A more specific object of the present invention is to provide a packaged image-pickup semiconductor device having a smaller thickness and area than a conventional image-pickup semiconductor device package.
In order to achieve the above-mentioned objects, there is provided according to one aspect of the present invention a semiconductor device for picking up an image, the device comprising:
a lens-mounting unit provided with a lens for picking up an image;
a semiconductor chip having a light-receiving element formed on a circuit-forming surface thereof, the light-receiving element converting light from the lens into an image signal;
a flexible substrate provided between the lens-mounting unit and the semiconductor chip so as to supply the image signal to an external circuit; and
a shading plate blocking light transmitting through the flexible substrate toward the semiconductor chip so as to substantially remove an influence of the light on the light-receiving element.
According to the present invention, the substrate on which the semiconductor chip is mounted is placed between the circuit-forming surface of the semiconduc
Honda Toshiyuki
Kida Susumu
Suzuki Hideo
Armstrong Westerman & Hattori, LLP
Elms Richard
Fujitsu Limited
Menz Douglas M
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