The present invention generally relates to an IC (integrated circuit) chip package and, more particularly, to a digital camera module with an image sensor chip package.
Image sensors are widely used in digital camera modules in order to convert the optical image data of an object into electrical signals. In order to protect the image sensor from contamination or pollution (i.e. from dust or water vapor), the image sensor is generally sealed in a structural package.
A typical image sensor chip package (not labeled) is illustrated in
In the process of forming the conductors 130, a number of interconnection holes 166 are defined in the base 146. The first portions 140 and the second portions 142 are formed by means of plating metal. The third portions 136 are formed by filling molten metal into the interconnection holes 166 and then allowing it to solidify. Accordingly, the first portion 140, the second portion 142 and the third portion 136 are electronically connected with each other. It is obvious that this method of forming the conductors 130 is complex and as a result it is also expensive. Furthermore, after the conductors 130 are formed, water vapor can enter the space 150 via the interconnection holes 166. Thus, the chip 152 may be polluted and the conductors 130 may be damaged.
In addition, the relative large volume of the image sensor chip package results in more dust-particles adhering to the cover 158, the bottom board 1462 and the sidewalls 1464 of the base 146. Thus, more dust-particles will drop onto the chip 152. The dust-particles obscure the optical path and produce errors in the image sensing process. Accordingly, the quality and/or reliability of the image sensor chip package 100 can be effected. Moreover, the bonding wires 156 exposed in the space 150 lack protection and may thus easily be damaged by dust-particles entering the space 150.
Therefore, a new image sensor chip package is desired in order to overcome the above-described shortcomings.
One embodiment of a chip package includes a carrier, an image sensor chip, a number of wires, an adhesive means and a transparent cover. The carrier includes a base and a leadframe. The base has a cavity therein. The leadframe includes a plurality of conductive pieces embedded in the base and are spaced from each other. The image sensor chip is mounted on the base and received in the cavity. The image sensor has a photosensitive area. The wires each electronically connect the image sensor chip and one corresponding conductive piece of the carrier. The adhesive means surrounds the image sensor chip and at least partially covers all the wires. The transparent cover is mounted to the carrier, the cover is adhered to the carrier with the adhesive means in a manner so as to define a sealing space for a photosensitive area of the image sensor chip therein, and the base and the cover allows one end of the conductive pieces to be exposed out therefrom.
Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Many aspects of the present image sensor chip package can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the image sensor chip package. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The barrel 10 is substantially a hollow cylinder with two open ends so that light can be transmitted therethrough. Several lens elements 12 are disposed in the barrel 10, and receive incoming light that enters from the outside. The barrel 10 has an outer thread 102 defined in an outer periphery wall thereof. A glass board 14 is disposed before the lens elements 12 and covers one end of the barrel 10. As such, the glass board 14 protects the lens elements 12 from being scraped or otherwise abraded and keeps dust from entering the system.
The seat 20 includes a seat body 202 and a flange 204 formed together. The seat body 202 is a hollow cylinder. The flange 204 is formed at a bottom end of the seat body 202. The flange 204 has a rectangular cavity 2042 defined in a middle thereof opposite to the seat body 202. The rectangular cavity 2042 communicates with the seat body 202 so that light can be transmitted therethrough. An outer diameter of the seat body 202 is smaller than an edge of the flange 204 so that a step is formed at a connection between them. An inner periphery wall of the seat body 202 defines an inner thread 201, for engaging with the outer thread 102 of the barrel 10.
The carrier 32 of the image sensor chip package 30 includes a leadframe 320 and a plastic base 324. The leadframe 320 and the plastic base 324 cooperatively form the carrier 32 by insert-molding.
Referring to
During insert-molding, the plastic base 324 partially encloses the upper and lower surfaces of the leadframe 320. One end of each of the first portions 3220 is exposed, thus forming a plurality of upper pads 326. A distal end of each of the third portions 3224 is exposed, thus forming a number of lower pads 328. After insert-molding, the leadframe 320 is cut along two sides. The carrier 32 is formed with a trapezoidal cavity. Referring to
The image sensor chip 34 is received in the trapezoidal cavity, and is adhered to the bottom of the carrier 32 via an adhesive glue 346. A top surface of the image sensor chip 34 is arranged with a photosensitive area 344 and a number of chip pads 342 around the photosensitive area 344. Alternatively, the adhesive glue 346 can be replaced by any other appropriate adhesive means.
The bonding wires 36 can be made of a conductive material such as gold or aluminum alloy. One end of each wire 36 is connected/joined with a respective chip pad 342 of the image sensor chip 34, and the other end of the wire 36 is connected/joined with a respective upper pad 326 forming by the first portions 3220 of the leadframe 320.
The cover 38 is transparent and is laid over the image sensor chip 34 which receives light transmitted through the cover 38. The cover 38 is adhered on the base 324 by glue (not labeled) and therefore seals the image sensor chip 34 in the cavity of the base 324.
The adhesive glue 3262, such as a silicone, epoxy, acrylic, or polyamide adhesive, is applied around the photosensitive area 344 of the image sensor chip 34. The adhesive glue 3262 surrounds all of the bonding wires 36 and covers the first portions 3220, and the inner surface of the carrier 32. The adhesive glue 3262 also fixes the cover 38 and defines a small sealing space 37 configured to seal the photosensitive area 344 therein. The bonding wires 36 and the adhesive glue 3262 are received in the carrier 32. It can be seen that the photosensitive area 344 of the image sensor chip 34 is sufficiently protected from outside pollution due to the small volume of the sealing space 37. The bonding wires 36 are protected by the adhesive glue 3262, and the leadframe 320 is protected by the base 324.
In assembly, several lens elements 12 are received in the barrel 10. The outer thread 102 of the barrel 10 engages with the inner thread 201 of the seat 20, whereby the barrel 10 and the seat 20 are connected with each other. The seat 20 is then mounted on the image sensor chip package 30 by welding/glue, with the image sensor 34 aligning with the lens elements 12. At the same time, the cover 38 is received in the rectangular cavity 2042. The assembly process of the digital camera module is thus completed.
In an alternative embodiment, the arrangement of the conductive pieces of the leadframe 320 can be changed so long as the conductive pieces 322 are spaced from each other. The second portion 3222 can be perpendicular to the first and third portions 3220, 3224 rather than being slanted. The base 324 can be of another shape such as cylinder-shaped, or column-shaped with a pentagonal or hexagonal cross-section.
In the above embodiments, the adhesive glue 3262 may only be disposed around the photosensitive area 344 so as to define a sealing space for protecting the photosensitive area 344. One main advantage of the digital cameral module with this image sensor chip package is its reliability and high image quality.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
Number | Date | Country | Kind |
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200510036587.2 | Aug 2005 | CN | national |
This application is related to a co-pending U.S. patent applications (Attorney Docket No.US7595), entitled “IMAGE SENSOR CHIP PACKAGE”, by Steven Webster et al. Such application has the same assignee as the present application and has been concurrently filed herewith. The disclosure of the above identified application is incorporated herein by reference.