Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2002-11-21
2004-03-16
Munson, Gene M. (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S432000
Reexamination Certificate
active
06707125
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state imaging apparatus and a manufacturing method thereof, in particular to a small-sized solid-state imaging apparatus with a semiconductor image pickup element therein, for example, for monitoring cameras, cameras for medical treatment and on-vehicle cameras, and to a manufacturing method thereof.
This type of imaging apparatus is popular these days. An image is inputted in the imaging apparatus via an optical system such as a lens or the like, and the imaging apparatus outputs the image as an electric signal. With the recent tendency toward small-sized and high-quality imaging apparatus, cameras are also small-sized and are much used in various fields, and the market share of the imaging apparatus of the type for image-inputting device is increasing.
In a conventional imaging apparatus with a solid-state image pickup element, the components of lenses, solid-state image pickup elements and LSIs with driving circuits and signal processing circuits mounted thereon is formed in the respective housings or package structures followed by combined them. The combined assembly is generally completed by mounting the constitutive components on a flat circuit-printing board.
For further size reduction, a three-dimensional printed circuit resin board
101
is proposed as shown in FIG.
5
and
FIG. 6
as well as Japanese Patent Publication No. 2001-245186. As illustrated, the printed circuit board
101
includes rectangular parallelepiped legs
101
A and a body
101
B standing thereon, and has an aperture
101
C in the boundary between the legs
101
A and the body
101
B. A printed wiring pattern
122
is formed on the back of each leg
101
A of the printed circuit board
101
. A lens
102
is fitted into the inner space of the body
101
B. Around the center of the optical axis
117
of the lens
102
, an optical filter
103
is disposed above the aperture
101
C, and a semiconductor image pickup element
104
, a type of a solid-state image pickup element, and chip parts
108
are disposed below the aperture
101
C. With a solder paste
114
, the semiconductor image pickup element
104
and the chip parts
108
are connected to the terminal pattern
122
formed around each leg
101
A. Thus constructed, the printed circuit board
101
is connected, via the solder paste
114
, to the main substrate
113
of various appliances such as mobile phones, personal computers and the like.
FIG. 7
is an explanatory view showing the main part of the printed circuit board
101
. As illustrated, the semiconductor image pickup element
104
is connected to a terminal pattern
105
formed on the surface of each leg
101
A, via a bump
106
formed on its surface, and this is sealed up with a sealant resin
107
so as to be integrated with the three-dimensional printed circuit board
101
. In these figures, the same reference numerals designate the same parts.
FIGS. 8A
to
8
C show a method of assembling the parts into an imaging apparatus. As illustrated, a three-dimensional printed circuit board
101
is formed (FIG.
8
A); then a solid-state image pickup element
104
is fitted to the printed circuit board
101
(FIG.
8
B); and thereafter an optical filter
103
is fitted to the printed circuit board
101
(FIG.
8
C).
In the method, therefore, the three-dimensional, the printed circuit board is greatly deformed in the heating step of fitting the solid-state image pickup element into the printed circuit board, and, as a result, the bonding area in which the solid-state image pickup element is bonded to the printed circuit board receives extremely large stress, and is often cracked to cause bonding failure.
The three-dimensional printed circuit board of the type as described above may be obtained through injection molding, which, however, is problematic in that only a predetermined small amount of ordinary extender pigment (filler) that serves for reducing the expansion coefficient of molding resin material could be added to the resin material to be molded, from the viewpoint of the molding accuracy and of the durability of the mold to be used for such injection molding.
Another problem with the injection-molding method is that ordinary thermoplastic resin suitable for injection molding has a linear molecule-bonding structure and is therefore anisotropic, or that is, its linear expansion coefficient is small in the molecule-bonding direction but is large in the direction perpendicular to the molecule-bonding direction.
As so mentioned in the above, in the heating step of fitting a solid-state image pickup element to a three-dimensional, printed circuit board is problematic in that the heated board is greatly deformed to thereby give extremely large stress to the bonding area in which the solid-state image pickup element is bonded to the board and, as a result, the bonding area is often cracked to cause bonding failure. In general, the bonding area is constituted by a pad attached to the solid-state image pickup element and a terminal electrode of the three-dimensional printed circuit board. In the bonding area, the image pickup element and the board are bonded to each other with an electroconductive adhesive such as silver paste or in a mode of ultrasonic bonding or thermal pressure bonding.
In any of these bonding methods, however, the three-dimensional printed circuit board is thermally deformed and the solid-state image pickup element is often peeled off from the deformed board. This is one reason for the low productivity in the known process.
As so mentioned hereinabove, the three-dimensionally structured, the printed circuit board enables small-sized solid-state imaging apparatus, but on the other hand, its thermal deformation is larger than that of ordinary flat boards. One serious problem with the three-dimensional printed circuit board is that its thermal deformation caused by the difference in the expansion coefficient between the constituent parts is great and is therefore an inevitable bar to the productivity increase in the known process.
The optical filter
103
is generally formed of a glass material of, for example, a crystal reflector or an IR (infrared)-cutting coated glass plate, and its thermal expansion coefficient is smaller than that of a resin material, and therefore its thermal deformation is also smaller than that of the resin material.
Given that situation, by first fitting the optical filter
103
to the printed circuit board
101
before the solid-state image pickup element is fitted thereto, this may solve the problem of thermal deformation of the board in the step of fitting the image pickup element to the board. In fact, however, the solid-state image pickup element must be directly bonded to the board via its bump, and thereafter the bonding area and therearound must be sealed up with a sealant resin. Accordingly, this method involves some other problems. For example, the gas generated in the sealing step will be trapped in the through-aperture
101
C and will react with the surface of the solid-state image pickup element under heat, or the gas will increase the inner pressure of the constructed device and will deteriorate the solid-state image pickup element, or it will deform the three-dimensional printed wiring board.
For these reasons, in manufacturing the imaging apparatus of the conventional structure, the optical filter must be fitted to the printed circuit board after the solid-state image pickup element has been fitted thereto.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the current situation as above, and is to prevent thermal deformation of the components such as the three-dimensional printed circuit board of solid-state imaging apparatus thereby to enable sure bonding of a solid-state image pickup element to the board and to improve the bonding quality of the solid-state image pickup element in the constructed imaging apparatus.
Given that situation, the solid-state imaging apparatus of the invention is so designed that the light transmitting member f
Matsushita Electric - Industrial Co., Ltd.
Munson Gene M.
Pearne & Gordon LLP
LandOfFree
Solid-state imaging apparatus and manufacturing method thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Solid-state imaging apparatus and manufacturing method thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solid-state imaging apparatus and manufacturing method thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3230795