Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2002-12-04
2004-11-30
Tran, Minhloan (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S432000, C257S433000, C257S434000, C361S736000, C361S737000
Reexamination Certificate
active
06825540
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a solid-state imaging apparatus and a manufacturing method thereof, and more particularly to a small-sized solid-state imaging apparatus including a solid-state image pickup element, such as a surveillance camera, a medical camera, or a vehicle camera, and a manufacturing method thereof.
An imaging apparatus of this kind receives an image through an optical system such as a lens, and outputs the image in the form of an electric signal. Recently, in accordance with miniaturization and enhancement of the performance of such an imaging apparatus, also the size of a camera is reduced, and an imaging apparatus is used in various fields and expands its market as an image inputting device.
In a conventional imaging apparatus using a solid-state image pickup element, each of components such as a lens, the solid-state image pickup element, and an LSI on which a driving circuit for the element and a signal processing circuit are mounted, has a shape of a case or a structure member, and the components are combined with each other. Conventionally, a mounting structure based on such a combination is formed by mounting elements onto a flat printed circuit board.
In order to further miniaturize such a device, a three-dimensional printed circuit board
101
shown in
FIGS. 17 and 18
was proposed in Japanese Patent Publication No. 2001-245186. The printed circuit board
101
is made of a resin in which a mounting member is configured by a leg portion
101
A having a rectangular table-like shape, and a body portion
101
B formed on the leg portion, and a through-opening portion
101
C is formed in the interface between the leg portion
101
A and the body portion
101
B. A printed wiring pattern
105
is formed on the three-dimensional printed circuit board on side of the rear face of the leg portion
101
A. A lens is fitted into the inner periphery of the body portion
101
B. While being centered at the optical axis
117
of the lens, an optical filter
103
is placed above the through-opening portion
101
C, and a solid-state image pickup element
104
and chip components
108
are placed below the through-opening portion. Further, by using solder
114
, the printed wiring pattern
105
formed on the leg portion
101
A is connected to a main board
113
of an apparatus such as a portable telephone or a personal computer.
FIG. 19
is a view showing main portions of the connections. The solid-state image pickup element
104
is connected to the printed wiring pattern
105
formed on the leg portion
101
A, through bumps
106
formed on the surface of the image pickup element
104
, and then sealed by a sealing resin
107
to accomplish the connections with the three-dimensional printed circuit board
101
.
The identical portions are denoted by the identical reference numerals.
Usually, such a three-dimensional printed circuit board is obtained by injection molding. However, there is a problem in that fillers, which are often used in order to reduce the coefficient of expansion of a resin material, cannot be added in an amount larger than a given one from the viewpoints of the molding accuracy and the durability of molding dies. In addition, fillers are oriented in the molding flow direction to exhibit anisotropic properties that the coefficient is large in a direction perpendicular to the molding flow direction.
A thermoplastic resin usually used in injection molding has a straight-chain molecular structure, and hence exhibits anisotropic properties that the coefficient of linear expansion is small in the molecular bonding direction and large in a direction perpendicular to the bonding direction. Therefore, there is a problem that the circuit board tends to be deformed, particularly, in the direction of a specific direction (a direction perpendicular to the molecular bonding direction).
Therefore, in a heating step in the process of mounting a solid-state image pickup element onto a three-dimensional printed circuit board, the three-dimensional printed circuit board is largely deformed, and a very high stress is generated in connecting portions between the solid-state image pickup element and the three-dimensional printed circuit board, so that a connection failure due to cracking often occurs.
Usually, such connecting portions between a solid-state image pickup element and a three-dimensional printed circuit board are configured by pads disposed on the solid-state image pickup element, and terminals of the three-dimensional printed circuit board. The connection between them is realized by connection using an electrically conductive adhesive agent such as silver paste, ultrasonic bonding, thermocompression bonding, or the like.
In any of the methods, the adhesion of the solid-state image pickup element is easily broken because of thermal deformation of the three-dimensional printed circuit board, and this causes the production yield to be lowered.
When a printed circuit board is three-dimensionally structured, thermal distortion is three times as large as that in the case of a usual two-dimensional structure, thereby causing a large problem in that deformation due to the difference in coefficient of expansion blocks improvement of the yield.
SUMMARY OF THE INVENTION
The invention has been conducted in view of the circumstances. It is an object of the invention to suppress thermal deformation of a resin structure member such as a three-dimensional printed circuit board to ensure connection of a solid-state image pickup element and improve the bonding quality of sealing glass for an optical filter or the like.
According to the present invention, a solid-state imaging apparatus comprises: a resin structure member which is configured by an insulating resin, and which has a through-opening portion; a wiring portion which is formed on a surface of the resin structure member; a solid-state image pickup element which is connected to the wiring portion, and which is attached to the through-opening portion; and a light-transmitting member which is disposed to cover the through-opening portion with being separated from the solid-state image pickup element by a predetermined distance, and a fixing member is placed in close proximity to a portion of the resin structure member to which the solid-state image pickup element is attached, the fixing member being smaller in coefficient of thermal expansion (coefficient in linear expansion) than the insulating resin.
According to the configuration, the fixing member such as a ceramic plate or a metal plate which is smaller in coefficient of thermal expansion than the insulating resin is disposed in the vicinity of the solid-state image pickup element attaching portion. Therefore, thermal deformation of the resin structure member made of the insulating resin can be suppressed, so that the certainty of the connection of the solid-state image pickup element can be enhanced. In the specification, the term “close proximity” means a distance of a degree at which the certainty of the connection of the solid-state image pickup element can be enhanced, including the case where the fixing member is in direct contact with or in the vicinity of the solid-state image pickup element attaching portion.
Moreover, occurrences of connection failures such as separation in an optical filter attaching portion can be reduced.
Preferably, the resin structure member has a leg portion on which the wiring portion is formed, and a cylindrical body portion which is disposed on the leg portion, and the through-opening portion is formed between the body portion and the leg portion.
When this configuration is applied to a conventional device, the whole structure may be miniaturized, but there arises a problem in that a connection failure due to deformation of a connecting portion is easily caused by thermal deformation. By contrast, according to the invention, the fixing member which is smaller in coefficient of thermal expansion than the insulating resin is placed, and therefore thermal deformation of the resin structure member mad
Harazono Fumikazu
Takade Yoshiharu
Dickey Thomas
Matsushita Electric - Industrial Co., Ltd.
Pearne & Gordon LLP
Tran Minhloan
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