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Digital Camera Patent Abstract
A digital camera module package method includes the steps of: firstly,
providing a carrier (30), which includes a base (24) and a leadframe
(320). The base has a cavity therein and the leadframe includes
a number of conductive pieces (322); Secondly, mounting an image
sensor chip (34) on the base and received in the cavity, the image
sensor having a photosensitive area. Thirdly, providing a plurality
of wires (36), each electrically connecting the image sensor chip
and a corresponding one of the conductive pieces of the carrier.
Fourthly, applying an adhesive means (3262) around the image sensor
chip that at least partially covers all the wires. Finally, mounting
a transparent cover (38) on the carrier, where an adhesive means
fixes the cover in place.
Digital Camera Patent Claims
1. A digital camera module package method, comprising the steps
of: providing a carrier comprising a base and a leadframe, the base
having a cavity therein, the leadframe comprising a plurality of
conductive pieces, the conductive pieces of the leadframe being
embedded in the base and spaced from each other; mounting an image
sensor chip in the cavity, the image sensor having a photosensitive
area; providing a plurality of wires, each electrically connecting
the image sensor chip with a corresponding one of the conductive
pieces of the carrier; applying an adhesive means around the image
sensor chip and at least partially covering all the wires; mounting
a transparent cover to the carrier, the adhesive means adhering
to the cover and configured 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 allowing one end of the conductive pieces
to be exposed out therefrom; and mounting a lens module on the cover.
2. The method as claimed in claim 16, wherein the each of the conductive
pieces of the leadframe comprises a first portion, a second portion
and a third portion, the first and second portions are parallel
to and spaced from each other, the second portion is slanted relative
to the first and third portions.
3. The method as claimed in claim 16, wherein the each of the conductive
pieces of the leadframe comprises a first portion, a second portion
and a third portion, the first and second portions are parallel
to and spaced from each other, the second portion is slanted relative
to the first and third portions.
4. The method as claimed in claim 16, wherein the carrier is formed
so as to allow it to enclose the leadframe in the base, and the
cavity is trapezoidal in shape.
5. The method as claimed in claim 16, wherein the cover is adhered
to the carrier by adhesive.
6. A method of fabricating a digital camera module, comprising
the steps of: providing a conductor element comprising a plurality
of leadframe, each leadframe made up of a plurality of conductive
pieces; injecting plastics to partially enclose the conductor element
to form a plurality of carriers connected to each other, each carrier
having a plurality of pads formed by the conductive pieces outside
the carrier; mounting image sensor chips in the carriers, each image
sensor chip having a photosensitive area and a plurality of chip
pads around the photosensitive area; providing a plurality of wires
each electrically connecting a corresponding one of the chip pads
of the image sensor chip and the conductive pieces; applying an
adhesive means around the photosensitive area of the image sensor
chip; and mounting a transparent cover to each carrier, the adhesive
means adhering to the cover, thereby defining a sealing space for
sealing the photosensitive area of the image sensor chip therein;
separating the carriers to form single carrier units; and mounting
a lens module on the cover.
7. The method as claimed in claim 6, wherein the adhesive means
surrounds the wires.
8. The method as claimed in claim 7, wherein the base of the carrier
has a cavity therein, and the conductive means comprises a plurality
of conductive pieces embedded in the base and spaced from each other.
9. The method as claimed in claim 9, wherein the conductor element
is manufactured by punching or etching on a metal sheet, and the
base is made of plastic materials.
10. The method as claimed in claim 9, wherein the carrier is manufactured
by insert-molding.
11. The method as claimed in claim 9, wherein each of the conductive
pieces of the conductive means comprises a first portion, a second
portion and a third portion, the first and third portions are parallel
to and spaced from each other, and the second portion is slanted
relative to the first and third portions.
12. The method as claimed in claim 7, wherein the lens module includes
a seat and a barrel, the seat includes a seat body and a flange,
the flange is mounted on the cover, and the seat body is connected
with the barrel.
13. The method as claimed in claim 13, wherein the barrel is connect
with the seat by thread.
14. The method as claimed in claim 13, wherein the barrel includes
a glass board, and the glass board is disposed on one end of the
barrel.
Digital Camera Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to a co-pending U.S. Patent
Application (Attorney Docket No.US7596), entitled "IMAGE SENSOR
CHIP PACKAGE FABRICATION METHOD", 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.
TECHNICAL FIELD
[0002] The present invention generally relates to an integrated
circuit (IC) chip package fabrication method and, more particularly,
to a digital camera module fabrication method with an image sensor
chip package.
BACKGROUND
[0003] With the development of wireless communication technologies,
increasing numbers of mobile phones and personal digital assistants
(PDAs) now include digital cameras as a special feature. Image sensors
are a core element of digital cameras. Therefore, 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.
[0004] A typical image sensor chip package method (not labeled)
is disclosed in Chinese Publication Number CN1518079 on Aug. 4,
2004, and is illustrated in FIG. 10. The image sensor chip package
method includes the following steps: firstly, a plurality of [-shaped
conductors 130 are provided. Secondly, plastics are injected to
partially enclose the conductors 130, thereby forming a base 146.
Some of the conductors 130 are exposed outside of the base 146.
Thirdly, a ring-like middle portion 148 is further formed on the
base 146 by means of injection. The base 146 and the middle portion
148 cooperatively form a space 150. Fourthly, an image sensor 152
having a plurality of pads 154 is disposed in the space 150. Fifthly,
a number of bonding wires 156 are provided to connect the pads 154
and the conductors 130. Finally, a cover 158 is secured to the top
of the middle portion 148 via an adhesive glue, thereby hermetically
sealing the space 150 and allowing light beams to pass therethrough.
[0005] In the process of connecting the wires 156, each wire 156
needs to be connected with the conductor 130. Furthermore, a larger
space is needed in order to conveniently operate. It is obvious
that this method of connecting wires 156 is complex and as a result
it is also expensive. 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 and the sidewalls 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 affected. 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.
[0006] Therefore, a new digital camera module fabrication method
is desired in order to overcome the above-described shortcomings.
SUMMARY OF THE INVENTION
[0007] One embodiment of a digital camera module package method
includes the steps of:
[0008] providing a carrier including a base and a leadframe, the
base having a cavity therein, the leadframe comprising a plurality
of conductive pieces, the conductive pieces of the leadframe being
embedded in the base and spaced from each other;
[0009] mounting an image sensor chip in the cavity, the image sensor
having a photosensitive area;
[0010] providing a plurality of wires, each electrically connecting
the image sensor chip and a corresponding one of the conductive
pieces of the carrier;
[0011] applying an adhesive means around the image sensor chip
and at least partially covering all the wires;
[0012] mounting a transparent cover to the carrier, the adhesive
means adhering to the cover and configured 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 allowing one end of the
conductive pieces to be exposed out therefrom; and
[0013] mounting a lens module on the cover.
[0014] Other advantages and novel features will become more apparent
from the following detailed description when taken in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Many aspects of the present digital camera module 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.
[0016] FIG. 1 is a schematic, cross-sectional view of a digital
camera module with an image sensor chip package according to a preferred
embodiment;
[0017] FIG. 2 is a schematic, top-down plan view of the leadframe
of FIG. 1;
[0018] FIG. 3 is a cross-sectional view of the leadframe in FIG.
2 along a line III-III;
[0019] FIG. 4 is a schematic, top view of the carrier formed by
insert-molding shown in FIG. 4;
[0020] FIG. 5 is a cross-sectional view after the image sensor
is put into the carrier;
[0021] FIG. 6 is a cross-sectional view showing the adhesive glue
surrounding all of the bonding wires;
[0022] FIG. 7 is a cross-sectional view showing the adhesive glue
fixing the cover and defining a small sealing space to seal the
photosensitive area;
[0023] FIG. 8 is a cross-sectional view showing therim of the image
sensor package;
[0024] FIG. 9 is a cross-sectional view showing the barrel and
the seat mounted on the image sensor package;
[0025] FIG. 10 is a schematic, cross-sectional view of a typical
image sensor chip package.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Referring to FIG. 1, a digital camera module includes a
barrel 10, a seat 20 and an image sensor chip package 30 in accordance
with a preferred embodiment. The image sensor chip package 30 includes
a carrier 32, a chip 34, a number of bonding wires 36 and a cover
38.
[0027] 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 in front of 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.
[0028] 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.
[0029] The carrier 32 of the image sensor chip package 30 includes
a number of conductive pieces 322 and a plastic base 324. The conductive
pieces 322 are spaced from each other and aligned in parallel, and
cooperatively form the carrier 32 when combined with the plastic
base 324.
[0030] The image sensor chip 34 is received in the carrier 32,
and is adhered to the bottom of the carrier 32 with 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.
[0031] The bonding wires 36 can be made of a conductive material
such as, for example, 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 conductive pieces
322.
[0032] 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 to the base 324 by glue (not labeled) and therefore
seals the image sensor chip 34 in the cavity of the base 324.
[0033] An 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 conductive pieces 322 are protected
by the base 324.
[0034] A method of fabricating the digital camera module 100 is
disclosed by way of example. In one embodiment, a plurality of image
sensor packages 30 are fabricated simultaneously to minimize the
cost associated with each individual image sensor package 30. Referring
to FIGS. 2 and 3, firstly, a conductor element 302 is provided.
The conductor element 320 is formed on a metal plate by etching.
The conductor element 321 includes a support beam 321, many groups
of conductive pieces 322 and a number of separate beams 323. The
conductive pieces 322 are punched so that each of the conductive
pieces 322 forms a first terminal portion 3220, a second connecting
portion 3222 and a third terminal portion 3224, where the second
connecting portion 3222 interconnects the first and third terminal
portions 3220, 3224. The first and third portions 3220, 3224 are
spaced apart and aligned in parallel to each other. The second portion
3222 is slanted relative to the first and third portions 3220, 3224.
Correspondingly, the conductive pieces 322 are divided into two
groups. The two groups are symmetrically arranged and the conductive
pieces in the same group are parallel to and spaced from each other,
thereby forming a plurality of leadframes 320 connected to each
other.
[0035] Secondly, the molten plastic is injected into the conductor
element 302 by insert-molding. The plastic is solidified to form
the plastic base 324. The plastic base 324 partially encloses the
upper and lower surfaces of each of the leadframes 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. The plastic
base 324 and each leadframe 130 cooperatively form carriers connected
to each other. Each carrier 32 is formed with a trapezoidal cavity.
[0036] Thirdly, referring to FIG. 5, each image sensor chip 34
is received in a corresponding trapezoidal cavity, and is adhered
to the bottom of the carrier 32 via an adhesive glue 346. Alternatively,
the adhesive glue 346 can be replaced by any other appropriate adhesive
means such as, for example, by metallurgical means.
[0037] Fourthly, referring to FIG. 6, 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.
[0038] Fifthly, referring to FIGS. 7 and 8, each cover 38 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 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 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.
[0039] After that, the conductor element 302 with the plastic base
are cut along the rim of each carrier 30 so as to separate a plurality
of carriers 30. At that time, distal ends of each of the conductive
pieces 322 are exposed outside. Usually, the conductive pieces 322
are shortened owing to a different shrinkage after the carriers
are cut. A kind of fuse technology such as ultrasonic fuse, laser
fuse or heat fuse may be used to irradiate the rim of the carrier.
Accordingly, the plastic base 324 are melted so as to enclose the
conductive pieces 322. By forming a plurality of image sensor packages
30 simultaneously, several advantages are realized. One advantage
is that it is less labor intensive to handle and process a plurality
of image sensor packages simultaneously rather than to handle and
process each image sensor package on an individual base. By reducing
labor, the cost associated with each package is minimized.
[0040] Finally, referring to FIG. 9, 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 100 is thus
completed.
[0041] 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. Understandably, the image sensor package may also
be produced in single units.
[0042] 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.
[0043] 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. |