Patent Application
20060016973
The present invention relates to an image sensor package module, and more particularly to a multi-chip image sensor package module for accommodating an image sensor chip at low cost.
Conventionally, an image sensor chip is integrated in a package module with other IC chips such as digital signal processor, IC, for electrical integrity. However, the dimension and thickness of the package module will increase. As disclosed in U.S. Pat. No. 6,686,588, a conventional image sensor package module includes an image sensor chip and electronic components connected to a substrate. The image sensor chip is attached to the upper surface of the substrate by adhesive. A sidewall with locking features is mounted on the upper surface to form a chip cavity for accommodating the image sensor chip and to assemble with a lens housing. The electronic components and solder balls are disposed on the lower surface of the substrate to form a package module. The package module is thicker and has a higher packaging cost.
A main purpose of the present invention is to provide a multi-chip image sensor package module comprising a substrate having an opening, an IC chip, an image sensor chip and a glass cover/lens. The IC chip including bumps is flip-chip mounted on the lower surface of the substrate. A chip cavity consists of the IC chip, the bumps and the opening of the substrate. The image sensor chip is disposed between the substrate and the IC chip so that the sensing region of the image sensor chip is aligned with the glass cover/lens via the opening. The package thickness of the multi-chip image sensor package module and the assemble cost can be reduced.
According to the present invention, a multi-chip image sensor package module comprises a substrate having an opening, an IC chip, an image sensor chip and a glass cover/lens. The opening is formed through the upper and lower surfaces of the substrate. The IC chip has a mounting surface and includes a plurality of bumps on the mounting surface. The IC chip is mounted on the lower surface of the substrate via the bumps. The bumps is formed at the peripheral region of the mounting surface without blocking the central region of the mounting surface, so that a chip cavity consists of the central region of the IC chip, the bumps and the opening of the substrate. The image sensor chip has an active surface and a backside surface. The active surface includes a sensing region smaller than the opening of the substrate. Moreover, the image sensor chip is disposed between the substrate and the IC chip inside the chip cavity in a manner that the sensing region is aligned with the glass cover/lens through the opening. Preferably, the central region of the mounting surface of the IC chip is no any bumps formed and is larger than the backside surface of the image sensor chip. The backside surface of the image sensor chip can be closer to the central region of the IC chip by chip-to-chip attachment on the central region or flip-chip mounting on the substrate. The glass cover/lens is disposed above the upper surface of the substrate to assemble a thin module.
Please refer to the drawings attached, the present invention will be described by means of embodiments below.
According to the first embodiment of the present invention, a multi-chip image sensor package module 100 is illuminated as shown in
According to the present embodiment, the IC chip 120 may be a flip chip or a chip scale package (CSP). The IC chip 120 has a mounting surface 121 and includes a plurality of bumps 122 formed on the mounting surface 121 of the IC chip 120. In this embodiment, the IC chip 120 is a DSP (Digital Signal Processor). The IC chip 120 is flip-chip mounted on the lower surface 112 of the substrate 110 via the bumps 122. The mounting surface 121 includes a central region 123 corresponding the backside surface 132 of the image sensor chip 130 and a peripheral region 124 around the central region 123. Bumps 122 are formed at the peripheral region 124 of the mounting surface 121 without blocking the central region 123. Therefore a chip cavity is formed which consists of the central region 123 of the IC chip 120, the bumps 122 and the opening 113 of the substrate 110. The image sensor chip 130 is disposed between the IC chip 120 and the substrate 110 inside the chip cavity, and can be even closer to the central region 123 of the IC chip 120. Furthermore, the dimension of the IC chip 120 should be larger than the image sensor chip 130.
The image sensor chip 130 has an active surface 131 and a backside surface 132. The active surface 131 includes a sensing region 133 for sensing images. The sensing region 133 is smaller than the opening 113 of the substrate 110. According to the embodiment, the opening 113 of the substrate 110 is smaller than the active surface 131 of the image sensor chip 130. The image sensor chip 130 is electrically connected to the substrate 110 by flip-chip mounting. The image sensor chip 130 includes a plurality of flip-chip bumps 134 to mount on the lower surface 112 of the substrate 110, wherein the sensing region 133 is aligned with the opening 113 of the substrate 110. Moreover, the area of the central region 123 of the IC chip 120 is almost equal to the area of the backside surface 132 of the image sensor chip 130. The bumps 122 connecting the lower surface 112 of the substrate 110 have a height larger than the thickness of the image sensor chip 130, so that the image sensor chip 130 can be disposed between the IC chip 120 and the substrate 110, and the active surface 131 and the backside surface 132 of the image sensor chip 130 are formed between the mounting surface 121 of the IC chip 120 the lower surface 112 of the substrate 110. The thickness of the multi-chip image sensor package module 100 can be reduced.
According to this embodiment, a lens module 140 is mounted on the upper surface 111 of the substrate 110. The lens module 140 includes a lens housing 141 to connect the lens 142. The lens housing 141 is airtightly connected to the substrate 110. Moreover, the lens 142 is aligned with the sensing region 133 of the image sensor chip 130 through the opening 113. Furthermore, a glass cover 143 is disposed above the upper surface 111 of the substrate 110 and is also aligned with the sensing region 133 of the image sensor chip 130 through the opening 113. According to this embodiment, the glass cover 143 is an IR-cut filter and is supported by the lens housing 141. Preferably, at least one passive component 150 is connected to the upper surface 111 or the lower surface 112. Moreover, an outer electrical connector 160, such as a flexible connector, can be connected to the lower surface 112 of the substrate 110 for outer connection.
In the multi-chip image sensor package module 100 mentioned above, the image sensor chip 130 is located between the substrate 110 and the IC chip 120 inside a composite chip cavity to achieve a thin module. Preferably, the package module 100 includes a filling material 170, such as a non-flow underfilling material, a non-conductive paste (NCP), or an anisotropic conductive paste (ACP). The filling material 170 is formed between the mounting surface 121 of the IC chip 120 and the lower surface 112 of the substrate 110 without contaminating the sensing region 133 of the image sensor chip 130 to encapsulate the bumps 122 and seal the image sensor chip 130. Therefore, the image sensor chip 130 is surrounded by an airtight space formed by the IC chip 120, the filling material 170, the opening 113 of the substrate 110 and the lens module 140 so that a thinner package module with lower package cost and excellent yield can be achieved.
According to the second embodiment of the present invention, as shown in
According to the third embodiment of the present invention, as shown in
The above description of embodiments of this invention is intended to be illustrative and not limiting. Other embodiments of this invention will be obvious to those skilled in the art in view of the above disclosure.
