U.S. patent application number 11/106671 was filed with the patent office on 2005-08-18 for flip-chip attach structure.
This patent application is currently assigned to Gigno Technology Co., Ltd.. Invention is credited to Liu, Shuan Ta.
Application Number | 20050179142 11/106671 |
Document ID | / |
Family ID | 33488653 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050179142 |
Kind Code |
A1 |
Liu, Shuan Ta |
August 18, 2005 |
Flip-chip attach structure
Abstract
A flip-chip attach method includes the steps of: attaching a
chip on a transparent substrate such that each connecting pad of
the chip is aligned with each electrical connection pad on the
transparent substrate; and irradiating each connecting pad and each
electrical connection pad from a side of the transparent substrate
with a laser beam so as to weld the connecting pad to the
electrical connection pad. Furthermore, the invention also provides
a flip-chip attach structure including a transparent substrate and
at least one chip. A surface of the transparent substrate is formed
with a plurality of electrical connection pads, and the chip has a
plurality of connecting pads. The connecting pads and the
electrical connection pads are irradiated with a laser beam and are
welded to each other. Thus, the chip is mounted to the transparent
substrate.
Inventors: |
Liu, Shuan Ta; (Yunghe City,
TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Gigno Technology Co., Ltd.
|
Family ID: |
33488653 |
Appl. No.: |
11/106671 |
Filed: |
April 15, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11106671 |
Apr 15, 2005 |
|
|
|
10856796 |
Jun 1, 2004 |
|
|
|
Current U.S.
Class: |
257/778 ;
257/E21.511; 257/E21.517 |
Current CPC
Class: |
H01L 2224/16 20130101;
H01L 2224/05573 20130101; H01L 2224/05571 20130101; H01L 2224/16227
20130101; H01L 2924/00014 20130101; H01L 2924/12042 20130101; H01L
2924/00014 20130101; H01L 2924/01079 20130101; H01L 24/81 20130101;
H01L 2924/07811 20130101; H01L 2924/01006 20130101; H01L 2924/12042
20130101; H01L 2924/01033 20130101; H01L 2224/81801 20130101; H01L
2224/16225 20130101; H01L 2924/00 20130101; H01L 2924/07811
20130101; H01L 2924/00 20130101; H01L 2224/05599 20130101; H01L
2224/13144 20130101; H01L 2924/014 20130101 |
Class at
Publication: |
257/778 |
International
Class: |
H01L 029/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2003 |
TW |
092115150 |
Claims
What is claimed is:
1. A flip-chip attach structure, comprising: a transparent
substrate having one surface formed with a plurality of electrical
connection pads; and at least one chip formed with a plurality of
connecting pads, wherein the connecting pads are respectively
welded to the electrical connection pads by irradiating the pads
with a laser beam so as to attach the chip on the transparent
substrate.
2. The structure according to claim 1, wherein each of the
connecting pads is further formed with a protrusion.
3. The structure according to claim 2, wherein the protrusion is a
solder bump.
4. The structure according to claim 2, wherein the protrusion is a
gold bump.
5. The structure according to claim 1, wherein each of the
electrical connection pads on the surface of the transparent
substrate is further formed with a protrusion.
6. The structure according to claim 5, wherein the protrusion is a
solder bump.
7. The structure according to claim 5, wherein the protrusion is a
gold bump.
8. The structure according to claim 1, wherein the transparent
substrate is a glass substrate.
Description
[0001] This application is a Divisional of co-pending application
Ser. No. 10/856,796, filed on Jun. 1, 2004, and for which priority
is claimed under 35 U.S.C. .sctn. 120; and this application claims
priority of Application No. 092115150 filed in Taiwan, R.O.C. on
Jun. 3, 2003 under 35 U.S.C. .sctn. 119; the entire contents of all
are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The invention relates to a flip-chip attach structure and a
flip-chip attach method, and more particularly to a flip-chip
attach structure and a flip-chip attach method for attaching a chip
to a transparent substrate.
[0004] 2. Related Art
[0005] In semiconductor package manufacturing processes, the
flip-chip attach technology is widely used. The so-called flip-chip
attach technology is, in brief, to form a plurality of protrusions
on an active surface of a chip, and then to mount the chip on a
substrate by the protrusions.
[0006] In general, the methods for attaching a chip to a substrate
in a flip-chip manner are categorized into three kinds including a
solder bump attach method, an anisotropic conductive adhesive film
(ACF) attach method and a gold-to-gold pressing attach method. As
shown in FIG. 1, the solder bump attach method is to form a solder
bump 112 on a connecting pad 111 of a chip 11 in advance, and then
the chip 11 is mounted on the substrate 12. As shown in FIG. 2 the
ACF attach method is to form a gold bump 113 on a connecting pad
111 of a chip 11, and then an anisotropic conductive adhesive film
13 is used to adhere the chip to the substrate 12. As shown in FIG.
3, the gold-to-gold pressing attach method is to form a gold
protrusion post 114 on a connecting pad 111 of a chip 11, and then
the chip is mounted on the substrate 12 by way of direct
pressing.
[0007] In the above-mentioned attach methods, the first and second
methods are used frequently, wherein the first attach method is
often used in the typical chip package processes while the second
attach method is often used in the LCD manufacturing processes. In
the LCD manufacturing processes, attaching the chip on the glass
substrate are usually performed using the ACF attach method, and
this technology is typically referred to as the COG (chip on glass)
technology. The problem that the second attach method most
frequently encounters is that the gold bump on the chip cannot
completely contact the gold ball in the anisotropic conductive
adhesive film, thereby reducing the product yield. In order to
avoid this problem of the reduced yield, the areas of the
connecting pad of the chip and the gold bump cannot be too small.
This will limit the further shrinking of the chip area. In
addition, because the anisotropic conductive adhesive film has to
be adhered to the glass substrate, the transparent property of the
glass substrate (transparent substrate) cannot be effectively
utilized in some applications. In particular, it is inconvenient in
the package application of the opto-electronic semiconductor
chip.
[0008] Consequently, it is an important subject to provide a chip
attach method capable of enhancing the connecting yield between the
chip and the transparent substrate, optimized utilization of the
transparent property of the transparent substrate, and reducing the
area of the connecting pad on the chip.
SUMMARY OF THE INVENTION
[0009] In view of the above-mentioned problems, the invention is to
provide a flip-chip attach method capable of enhancing the
connecting yield between the chip and the transparent substrate,
optimized utilization of the transparent property of the
transparent substrate, and reducing the area of the connecting pad
on the chip.
[0010] Furthermore, the invention is to provide a flip-chip attach
structure capable of enhancing the connecting yield between the
chip and the transparent substrate, optimized utilization of the
transparent property of the transparent substrate, and reducing the
area of the connecting pad on the chip.
[0011] To achieve the above, the invention provides a flip-chip
attach method including the steps of: attaching a chip on a
transparent substrate and making each connecting pad on the chip in
alignment with each electrical connection pad on the transparent
substrate; and irradiating each connecting pad and each electrical
connection pad with a laser beam from a side of the transparent
substrate so as to weld the connecting pad to the electrical
connection pad.
[0012] In addition, the flip-chip attach structure of the invention
includes a transparent substrate and at least one chip, wherein a
surface of the transparent substrate is formed with a plurality of
electrical connection pads. The chip has connecting pads, which are
respectively welded to the electrical connection pads by
irradiating a laser beam, so that the chip is attached on the
transparent substrate.
[0013] As mentioned above, the flip-chip attach structure and
method of the invention weld the chip to the transparent substrate
using a high-energy and precisely controlled laser beam. Thus, as
long as the connecting pad is at the same surface height with or
protrudes over the active surface of the chip, or the electrical
connection pad is formed on the transparent substrate with a
predetermined height, the connecting pad of the chip can be welded
to the electrical connection pad of the transparent substrate. That
is, even if no protrusion is formed on the connecting pad of the
chip and the electrical connection pad of the transparent
substrate, the chip still can be welded to the transparent
substrate, so the connecting yield between the chip and the
transparent substrate may be enhanced. In addition, because the
substrate is a transparent substrate, it is possible to fully
utilize its transparent property according to the flip-chip attach
structure and method of the invention. Furthermore, because the
flip-chip attach structure and method of the invention weld the
chip to the transparent substrate with the laser beam, the area of
the connecting pads of the chip and that of the electrical
connection pads of the transparent substrate need not to be too
large. And, even if no protrusion is formed on the connecting pads
of the chip and the electrical connection pads of the transparent
substrate, the chip still can be welded to the transparent
substrate. In other words, the flip-chip attach structure and
method of the invention are advantageous to the reducing of the
area of the connecting pads on the chip.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will become more fully understood from the
detailed description given hereinbelow illustration only, and thus
is not limitative of the present invention, and wherein:
[0015] FIG. 1 is a schematic illustration showing a chip, which is
mounted on a substrate using a conventional solder bump attach
method;
[0016] FIG. 2 is a schematic illustration showing a chip, which is
mounted on a substrate using a conventional ACF (anisotropic
conductive adhesive film) attach method;
[0017] FIG. 3 is a schematic illustration showing a chip, which is
mounted on a substrate using a conventional gold-to-gold pressing
attach method;
[0018] FIG. 4 is a flow chart showing a flip-chip attach method
according to a preferred embodiment of the invention;
[0019] FIG. 5 is a schematic illustration showing a flip-chip
attach structure according to the preferred embodiment of the
invention; and
[0020] FIG. 6 is a schematic illustration showing another flip-chip
attach structure according to another preferred embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The flip-chip attach method according to the preferred
embodiment of the invention will be described with reference to the
accompanying drawings. The flip-chip attach method according to the
preferred embodiment of the invention is for attaching a chip on a
transparent substrate, wherein the chip is formed with a plurality
of connecting pads and a surface of the transparent substrate is
formed with a plurality of electrical connection pads.
[0022] Referring to FIG. 4, the flip-chip attach method according
to the preferred embodiment of the invention includes a step S1 and
a step S2. In step S1, the chip is firstly attached on the
transparent substrate and each connecting pad on the chip is in
alignment with each electrical connection pad on the transparent
substrate. In step S2, each connecting pad and each electrical
connection pad are respectively irradiated with a laser beam from a
side of the transparent substrate, so that the connecting pad is
welded to the electrical connection pad. It is to be specified that
when the connecting pad of the chip is directly attached to the
electrical connection pad of the transparent substrate, the
connecting pad of the chip is preferably at the same surface height
with the active surface of the chip, or preferably protrudes over
the active surface of the chip so as to be conveniently welded to
the electrical connection pad of the transparent substrate. Of
course, in order to facilitate the welding process, the electrical
connection pad of the transparent substrate may have a
predetermined height. In addition, in the flip-chip attach method
of the invention, the transparent substrate may be a glass
substrate.
[0023] In addition, in the flip-chip attach method of the
invention, a protrusion, which may be a solder bump or a gold bump,
may further be formed on each connecting pad of the chip. Of
course, each electrical connection pad of the transparent substrate
also may be formed with a protrusion, which may be a solder bump,
or a gold bump. Consequently, the welding property between the chip
and the transparent substrate may be further enhanced. That is, in
the flip-chip attach method of the invention, each connecting pad
may be directly welded to each electrical connection pad, or
indirectly welded to each electrical connection pad via the
protrusion.
[0024] As mentioned above, the flip-chip attach method of the
invention welds the chip to the transparent substrate using a
high-energy and precisely controlled laser beam. Thus, as long as
the connecting pad is at the same surface height with or protrudes
over the active surface of the chip, or the electrical connection
pad is formed on the transparent substrate with a predetermined
height, the connecting pad of the chip can be welded to the
electrical connection pad of the transparent substrate. That is,
even if no protrusion is formed on the connecting pad of the chip
and the electrical connection pad of the transparent substrate, the
chip still can be welded to the transparent substrate, so the
connecting yield between the chip and the transparent substrate may
be enhanced. In addition, in the flip-chip attach method of the
invention, because the substrate is a transparent substrate, it is
possible to fully utilize its transparent property. Furthermore,
because the flip-chip attach method of the invention welds the chip
to the transparent substrate with the laser beam, the area of the
connecting pads of the chip and that of the electrical connection
pads of the transparent substrate need not to be too large. In
other words, the flip-chip attach method of the invention is
advantageous to the reducing of the area of the connecting pads on
the chip.
[0025] The flip-chip attach structure according to the preferred
embodiment of the invention will be described with reference to
FIGS. 5 and 6.
[0026] With reference to FIG. 5, the flip-chip attach structure
according to the preferred embodiment of the invention includes a
transparent substrate 21 and at least one chip 22. The surface of
the transparent substrate 21 is formed with a plurality of
electrical connection pads 211. The chip 22 has a plurality of
connecting pads 221, and the connecting pads 221 are respectively
welded to the electrical connection pads 211 by irradiating a laser
beam (the arrow in the drawing) to the pads so that the chip 22 can
be mounted on the transparent substrate 21. In this embodiment, the
transparent substrate may be a glass substrate. In addition, when
the connecting pad 221 of the chip 22 is directly attached to the
electrical connection pad 211 of the transparent substrate 21, the
connecting pad 221 of the chip 22 is preferably at the same surface
height with or protrudes over the active surface of the chip 22 so
as to facilitate the welding between the connecting pad 221 of the
chip 22 and the electrical connection pad 211 of the transparent
substrate 21. Of course, in order to facilitate the welding
process, the electrical connection pad 211 of the transparent
substrate 21 may have a predetermined height.
[0027] In addition, as shown in FIG. 6, each connecting pad 221 of
the chip 22 may further be formed with a protrusion 222, which may
be a solder bump, or a gold bump. Of course, each electrical
connection pad 211 of the transparent substrate 21 also may be
formed with a protrusion (not shown), which may be a solder bump,
or a gold bump. Consequently, the welding property between the chip
22 and the transparent substrate 21 could be enhanced. That is, in
the flip-chip attach structure of the invention, each connecting
pad 221 may be directly welded to each electrical connection pad
211 or indirectly welded to each electrical connection pad 211 via
the protrusion.
[0028] As mentioned above, the flip-chip attach structure of the
invention utilizes a high-energy and precisely controlled laser
beam to weld the chip to the transparent substrate. Thus, as long
as the connecting pad is at the same height with or protrudes over
the active surface of the chip, or the electrical connection pad is
formed on the transparent substrate with a predetermined height,
the connecting pad of the chip can be welded to the electrical
connection pad of the transparent substrate. That is, even if no
protrusion is formed on the connecting pad of the chip and the
electrical connection pad of the transparent substrate, the chip
still can be welded to the transparent substrate, so the welding
yield between the chip and the transparent substrate may be
enhanced. In addition, because the substrate is a transparent
substrate, it is possible to fully utilize its transparent property
in the flip-chip attach structure of the invention. Furthermore,
because the flip-chip attach structure of the invention welds the
chip to the transparent substrate with the laser beam, the area of
the connecting pads of the chip and that of the electrical
connection pads of the transparent substrate need not to be too
large. In other words, the flip-chip attach structure of the
invention is advantageous to the reducing of the area of the
connecting pads on the chip.
[0029] Although the invention has been described with reference to
specific embodiments, this description is not meant to be construed
in a limiting sense. Various modifications of the disclosed
embodiments, as well as alternative embodiments, will be apparent
to persons skilled in the art. It is, therefore, contemplated that
the appended claims will cover all modifications that fall within
the true scope of the invention.
* * * * *