JPH10144898A - Solid state image pickup apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize low cost hollow package structure by joining a base substrate, a solid state image pickup element and a resin frame at the upper end portion of a resin frame under the condition that the predetermined space is secured between the element mounting surfaces of a base substrate and then hermetically sealing a solid state image pickup element on the base substrate in the predetermined space. SOLUTION: A base substrate 2 integrally forming a conductive film 7 is formed on a substrate, and a solid state image pickup element 3 is joined to be fixed on the base substrate 2. The electrode of a solid state image pickup element and one end 7a of the conductive film 7 are connected with a bonding wire 8 and resin having high viscosity is applied surrounding the solid state image pickup element 3 on the base substrate 2 to form the resin frame 4 in the predetermined height on the base substrate 2. A transparent plate 5 is pressed on the upper end of the resin frame 4 to harden the resin frame 4. Simultaneously, height of the resin frame 4 is adjusted to the final height. Thereby, material cost and processing cost of the base substrate 2 can be lowered as mush as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device such as a CCD linear sensor or a CCD area sensor.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a package structure of a solid-state image pickup device of this type, and FIG. 4 is an exploded perspective view thereof. In the illustrated solid-state imaging device 30, a solid-state imaging device 32 is mounted on a ceramic substrate 31 serving as a base. The ceramic substrate 31 has a multilayer structure of three or more layers, and a predetermined number of conductive films 33a are provided between the layers.
Are patterned. One end of each conductive film 33a is arranged close to the peripheral portion of the solid-state imaging device 32 on the ceramic substrate 31, and a bonding wire 34 drawn out from an electrode portion (aluminum pad portion) of the solid-state imaging device 32 (see FIG. 3). ) Is connected. On the other hand, the other end of each conductive film 33a is exposed on the outer surface of the ceramic substrate 31, and a side conductive film 33b is formed on the exposed portion. A lead terminal 35 is brazed to each side conductive film 33b so as to extend vertically to the back side of the ceramic substrate 31. Further, a seal glass 36 is joined to the upper end of the ceramic substrate 31, and the solid-state imaging device 32 is hermetically sealed by the seal glass 36.

[0003]

However, in the above-mentioned conventional solid-state imaging device 30, a ceramic substrate 31 having a multilayer structure is adopted, the inside of the substrate is formed in a step shape, and the solid-state imaging device 32 is mounted on the bottom surface of the concave portion. Since a space (hollow portion) for hermetic sealing is secured, the substrate manufacturing process becomes complicated due to the mutual bonding of the substrates, and the ceramic substrate 3
(1) There is a problem that material costs and processing costs are increased.

In recent years, there has been proposed a package structure in which a solid-state imaging device is mounted on a base substrate having a flat plate structure, and the solid-state imaging device is potted and sealed with a light-transmitting resin. Since the light receiving surface of the solid-state imaging device is directly covered with the resin, the following problems have occurred. (1) The effect of the on-chip microlens formed on the solid-state imaging device cannot be obtained. (2) Fine dust adhering to the surface of the base substrate is taken into the resin, and the dust moves on the light receiving surface of the element due to the fluidity of the resin, resulting in poor characteristics. (3) Bubbles are easily generated in the resin, and the presence of such bubbles causes poor characteristics such as image distortion. (4) When dust adhering to the resin surface is cleaned with a cotton swab or the like, the resin surface is easily scratched, resulting in poor image quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a solid-state imaging device which realizes a very inexpensive hollow package structure.

[0006]

A solid-state imaging device according to the present invention comprises a base substrate having a flat plate structure, a solid-state imaging device mounted on the base substrate, and a solid-state imaging device mounted on the base substrate so as to surround the solid-state imaging device. The resin frame formed at a predetermined height and the upper surface of the resin frame in a state where a predetermined space is secured between the element mounting surface of the base substrate and the solid-state imaging device on the base substrate is fixed to a predetermined position. And a transparent plate hermetically sealed in the space.

In the solid-state imaging device having the above-described structure, a base substrate having a flat plate structure is employed, a solid-state imaging device is mounted on the base substrate, and a transparent plate is provided on an upper end of a resin frame surrounding the solid-state imaging device. , And the solid-state imaging device is hermetically sealed with the transparent plate, so that the substrate manufacturing process is greatly simplified as compared with the conventional hollow package structure. Further, since the solid-state imaging device is hermetically sealed in a predetermined space (hollow portion), no trouble occurs when the potting sealing structure is adopted.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of a solid-state imaging device according to the present invention,
FIG. 2 is a sectional view thereof. The illustrated solid-state imaging device 1 includes:
It is mainly composed of a base substrate 2, a solid-state imaging device 3, a resin frame 4, and a transparent plate 5.

The base substrate 2 has a very simple flat plate structure, and is made of a ceramic substrate which generates little dust. On the opposite sides of the base substrate 2, semicircular concave portions 6, 6,... Are integrally formed at predetermined intervals. Further, a conductive film 7 having a substantially U-shaped cross section is formed on the base substrate 2 via the respective concave portions 3 described above. The conductive film 7 is made of, for example, Ag or Au.
One end portion 7a is arranged close to the peripheral portion of the solid-state imaging device 3, which is made of a so-called thick film conductor material such as a base noble metal paste or a Cu or Ni base metal paste. On the other hand, the other end portion 7b of the conductive film 7 extends to a surface (lower surface in the figure) opposite to the device mounting surface of the base substrate 2, and the extended portion is exposed to the substrate surface to form an electrode portion for external connection. And

The solid-state imaging device 3 is composed of a CCD device or the like, and is mounted at the center of the upper surface of the base substrate 2.
A plurality of electrode portions (not shown) are formed on a peripheral portion of the upper surface of the solid-state imaging device 3, and a bonding wire 8 (see FIG. 2) such as a gold wire drawn from these electrode portions is connected to one end of the conductive film 7. It is connected to the unit 7a.

The resin frame 4 is formed so as to surround the solid-state imaging device 3 on the base substrate 2. More specifically, the resin frame 4 is formed on the base substrate 2 so as to be outside the connection between the one end 7 a of the conductive film 7 and the bonding wire 8 and to cover a part of the conductive film 7. The height of the resin frame 4 is set to be larger than the sum of the thickness of the solid-state imaging device 3 and the loop height of the bonding wires 8.

As a material of the resin frame 4, a resin having good adhesiveness to the base substrate 2 and the transparent plate 5 and having thermosetting or ultraviolet curable properties, for example, silicone resin, epoxy resin, acrylic resin, etc. Can be adopted. In addition, from the viewpoint of manufacturing the device, a resin having high viscosity and high thixotropy is preferable in order to maintain the raised shape. Further, a silicone resin or the like having appropriate elasticity is preferable in terms of relaxation of thermal stress, and an epoxy resin or an acrylic resin is preferable in terms of moisture resistance.

The transparent plate 5 secures a predetermined space between the transparent board 5 and the device mounting surface of the base substrate 2, in this case, a space that does not interfere with the bonding wires 8 drawn from the solid-state image sensor 3. At the upper end of the resin frame 4. The transparent plate 5 is similar to a seal glass used in a well-known hollow package structure. By closing the opening of the resin frame 4 with the transparent plate 5, the solid-state imaging is performed in the above-described predetermined space. The element 3 is hermetically sealed.

Here, a procedure for manufacturing the solid-state imaging device 1 of the present embodiment will be briefly described. First, a base substrate 7 is formed by integrally forming a conductive film 7 on a substrate, and the solid-state imaging device 3 is bonded and fixed on the base substrate 7 via a die bonding agent. Next, an electrode unit (not shown) of the solid-state imaging device 3
And one end 7 a of the conductive film 7 are connected by a bonding wire 8. Next, a high-viscosity resin is applied around the solid-state imaging device 3 on the base substrate 2 to form a resin frame 4 having a predetermined height on the base substrate 2. At this time, the height of the resin frame 4 is set to a transparent plate 5 described later.
In order to secure the joint surface with the final height, the height is set slightly higher than the final specified height. Subsequently, the transparent plate 5 is pressed against the upper end of the resin frame 4 and the resin frame 4 is cured by heating or irradiating ultraviolet rays in this state. At this time, the upper end of the resin frame 4 is crushed by the transparent plate 5 to form a surface-joined state, and at the same time, the height of the resin frame 4 is adjusted to the final specified height. Thus, the solid-state imaging device 1 shown in FIGS. 1 and 2 is obtained.

In this embodiment, a high-viscosity resin is applied on the base substrate 2 when forming the resin frame 4.
The resin in the (stage) state may be preliminarily formed into a frame shape, and this may be sandwiched between the base substrate 2 and the transparent plate 5 and both may be thermocompression-bonded simultaneously.

As described above, in the solid-state imaging device 1 of the present embodiment, the base substrate 2 having a very simple flat plate structure is employed, and the resin frame 4 is formed on the base substrate 2 so as to surround the solid-state imaging device 3. Is formed, and the solid-state imaging device 3 is hermetically sealed with the transparent plate 5, so that the substrate manufacturing process is greatly simplified as compared with the related art, thereby reducing material and processing costs of the base substrate 2. It is possible to keep it as low as possible. Further, since the resin frame 4 having a predetermined height is interposed between the base substrate 2 and the transparent plate 5, it is possible to effectively absorb the thermal stress generated between the two substrates, thereby causing the thermal stress. It is also possible to prevent the cracked resin frame 4 and peeling at each joint. Further, in the solid-state imaging device according to the present invention, the electrode portion for external connection can be formed of a lead terminal as in the conventional hollow package structure. By using the end 7b of the conductive film 7 exposed to the side as an electrode portion for external connection, further cost reduction can be expected.

In the above-described embodiment, a ceramic substrate is used as the base substrate 2, but a glass epoxy substrate or the like may be used instead.

[0018]

As described above, according to the solid-state imaging device of the present invention, a base substrate having a flat plate structure is employed, a solid-state imaging device is mounted on the base substrate, and a resin surrounding the solid-state imaging device. Join the transparent plate to the upper end of the frame,
Since a structure in which the solid-state imaging device is hermetically sealed with this transparent plate is employed, the substrate manufacturing process is greatly simplified as compared with the conventional hollow package structure. As a result, the material cost and processing cost of the base substrate are reduced, so that the cost of the solid-state imaging device can be reduced. Further, since the solid-state imaging device is hermetically sealed in a predetermined space, various problems when the potting sealing structure is employed can be reliably avoided.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a solid-state imaging device according to the present invention.

FIG. 2 is a cross-sectional view showing one embodiment of a solid-state imaging device according to the present invention.

FIG. 3 is a cross-sectional view illustrating a structure of a conventional solid-state imaging device.

FIG. 4 is an exploded perspective view showing the structure of a conventional solid-state imaging device.

[Description of Signs] 1 solid-state imaging device 2 base substrate 3 solid-state imaging device 4 resin frame 5 transparent plate 7 conductive film

Claims (2)

[Claims] A base substrate having a flat plate structure; a solid-state imaging device mounted on the base substrate; and a resin frame formed at a predetermined height on the base substrate so as to surround the solid-state imaging device. Is bonded to the upper end of the resin frame in a state where a predetermined space is secured between the device mounting surface of the base substrate and the solid-state imaging device on the base substrate is hermetically sealed in the predetermined space. A solid-state imaging device comprising: a transparent plate. 2. The solid-state imaging device according to claim 1, wherein the base substrate has an end portion of a conductive film patterned on the substrate as an electrode portion for external connection.