U.S. patent application number 13/893623 was filed with the patent office on 2013-09-26 for method for manufacturing fine-pitch bumps and structure thereof.
This patent application is currently assigned to CHIPBOND TECHNOLOGY CORPORATION. The applicant listed for this patent is CHIPBOND TECHNOLOGY CORPORATION. Invention is credited to Hua-An Dai, Yung-Wei Hsieh, Cheng-Fan Lin, Shu-Chen Lin, Cheng-Hung Shih.
Application Number | 20130249089 13/893623 |
Document ID | / |
Family ID | 48876331 |
Filed Date | 2013-09-26 |
United States Patent
Application |
20130249089 |
Kind Code |
A1 |
Shih; Cheng-Hung ; et
al. |
September 26, 2013 |
METHOD FOR MANUFACTURING FINE-PITCH BUMPS AND STRUCTURE THEREOF
Abstract
A method for manufacturing fine-pitch bumps comprises the steps
of providing a silicon substrate; forming a titanium-containing
metal layer on the silicon substrate, wherein the
titanium-containing metal layer comprises a plurality of first
zones and a plurality of second zones; forming a photoresist layer
on the titanium-containing metal layer; patterning the photoresist
layer to form a plurality of opening slots; forming a plurality of
copper bumps at the opening slots, wherein each of the copper bumps
comprises a first top surface and a ring surface; heating the
photoresist layer to form a plurality of body portions and a
plurality of removable portions; etching the photoresist layer; and
removing the second zones to enable each of the first zones to form
an under bump metallurgy layer having a bearing portion and an
extending portion.
Inventors: |
Shih; Cheng-Hung; (Changhua
County, TW) ; Hsieh; Yung-Wei; (Hsinchu City, TW)
; Lin; Shu-Chen; (Pingtung County, TW) ; Lin;
Cheng-Fan; (Hsinchu County, TW) ; Dai; Hua-An;
(Kaohsiung City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHIPBOND TECHNOLOGY CORPORATION |
Hsinchu |
|
TW |
|
|
Assignee: |
CHIPBOND TECHNOLOGY
CORPORATION
Hsinchu
TW
|
Family ID: |
48876331 |
Appl. No.: |
13/893623 |
Filed: |
May 14, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13426810 |
Mar 22, 2012 |
8501614 |
|
|
13893623 |
|
|
|
|
Current U.S.
Class: |
257/737 |
Current CPC
Class: |
H01L 2224/03912
20130101; H01L 2224/05666 20130101; H01L 2224/05666 20130101; H01L
24/03 20130101; H01L 2224/13562 20130101; H01L 2224/13664 20130101;
H01L 2224/05022 20130101; H01L 2224/034 20130101; H01L 2224/13655
20130101; H01L 2224/13655 20130101; H01L 2224/13582 20130101; H01L
2224/13664 20130101; H01L 24/13 20130101; H01L 2224/13147 20130101;
H01L 2224/05666 20130101; H01L 2224/11906 20130101; H01L 2224/05552
20130101; H01L 2224/0401 20130101; H01L 2924/00014 20130101; H01L
2224/13007 20130101; H01L 2224/13147 20130101; H01L 2224/13644
20130101; H01L 2924/00014 20130101; H01L 24/05 20130101; H01L
2224/05666 20130101; H01L 2224/11472 20130101; H01L 23/49811
20130101; H01L 24/11 20130101; H01L 2224/05571 20130101; H01L
2224/13644 20130101; H01L 2224/034 20130101; H01L 2924/01029
20130101; H01L 2924/00014 20130101; H01L 2924/00014 20130101; H01L
2924/01074 20130101; H01L 2924/01029 20130101; H01L 2924/00014
20130101; H01L 2924/01079 20130101; H01L 2924/00014 20130101; H01L
2924/01074 20130101; H01L 2924/00014 20130101; H01L 2924/00014
20130101; H01L 2924/00014 20130101 |
Class at
Publication: |
257/737 |
International
Class: |
H01L 23/498 20060101
H01L023/498 |
Claims
1. A fine-pitch bump structure at least comprising: a silicon
substrate having a surface, a plurality of bond pads disposed at
the surface and a protective layer disposed at the surface, wherein
the protective layer comprised a plurality of openings, and the
bond pads are revealed by the openings; a plurality of under bump
metallurgy layers formed on the bond pads, each of the under bump
metallurgy layers comprises a bearing portion and an extending
portion; a plurality of copper bumps formed on the under bump
metallurgy layers, each of the copper bumps comprises a first top
surface and a ring surface, the bearing portion of each of the
under bump metallurgy layers is located under each of the copper
bumps, and the extending portion of each of the under bump
metallurgy layers is protruded to the ring surface of each of the
copper bumps; a plurality of bump protection layers formed on the
extending portions of the under bump metallurgy layers, the first
top surface and the ring surface of each of the copper bumps, each
of the bump protection layers comprises a metallic coverage portion
and a bump coverage portion having a second top surface, wherein
the first top surface and the ring surface of each of the copper
bumps are covered with each of the bump coverage portions, and each
of the extending portions is covered with each of the metallic
coverage portions; and a plurality of wettable layers formed on the
second top surfaces of the bump coverage portions.
2. The fine-pitch bump structure in accordance with claim 1,
wherein each of the bump coverage portions comprises a first outer
lateral surface, each of the metallic coverage portions comprises a
second outer lateral surface and is protruded to the first outer
lateral surface of the bump coverage portion.
3. The fine-pitch bump structure in accordance with claim 2,
wherein the extending portion of each of the under bump metallurgy
layers comprises a third outer lateral surface coplanar with the
second outer lateral surface.
4. The fine-pitch bump structure in accordance with claim 1,
wherein the material of the bump protection layers can be chosen
from one of nickel, palladium or gold.
5. The fine-pitch bump structure in accordance with claim 1,
wherein the under bump metallurgy layers are made of a material
selected from one of titanium/tungsten/gold, titanium/copper and
titanium/tungsten/copper.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally related to a method for
manufacturing fine-pitch bumps, which particularly relates to the
method for manufacturing fine-pitch bumps that prevents copper ions
from dissociation.
BACKGROUND OF THE INVENTION
[0002] In structure of fine-pitch bumps, a short phenomenon is
easily occurred from a relatively short gap between two adjacent
copper bumps owing to the copper ion dissociated by the copper
bump.
SUMMARY
[0003] The primary object of the present invention is to provide a
method for manufacturing fine-pitch bumps comprising the following
steps of providing a silicon substrate having a surface, a
plurality of bond pads disposed at the surface and a protective
layer disposed at the surface, wherein the protective layer
comprises a plurality of openings, and the bond pads are revealed
by the openings; forming a titanium-containing metal layer on the
silicon substrate, the titanium-containing metal layer comprises a
plurality of first zones and a plurality of second zones located
outside the first zones, the protective layer and the bond pads are
covered with the titanium-containing metal layer; forming a
photoresist layer on the titanium-containing metal layer;
patterning the photoresist layer to form a plurality of opening
slots corresponded to the first zones of the titanium-containing
metal layer; forming a plurality of copper bumps at the opening
slots, each of the copper bumps comprises a first top surface and a
ring surface; heating the photoresist layer to ream the opening
slots of the photoresist layer, and the heat process enables the
photoresist layer to form a plurality of body portions and a
plurality of removable portions; etching the photoresist layer to
remove the removable portions and expose the titanium-containing
metal layer; forming a plurality of bump protection layers on the
titanium-containing metal layer, the first top surface and the ring
surface of each of the copper bumps, wherein each of the bump
protection layers comprises a metallic coverage portion and a bump
coverage portion having a second top surface, the first top surface
and the ring surface of each of the copper bumps are covered with
the bump coverage portion; forming a plurality of wettable layers
on the second top surfaces; removing the body portions of the
photoresist layer; eventually, removing the second zones of the
titanium-containing metal layer to enable each of the first zones
of the titanium-containing metal layer to form an under bump
metallurgy layer located under each of the copper bumps, each of
the under bump metallurgy layers comprises a bearing portion
located under each of the copper bumps and an extending portion
protruded to the ring surface of each of the copper bumps, and the
extending portion of each of the under bump metallurgy layers is
covered with the metallic coverage portion of each of the bump
protection layers. The protection of the bump protection layers may
lower dissociation of copper ions released from the copper bumps,
which improves reliability of the fine-pitch bump structure
effectively. Besides, the protection also prevents the copper bumps
from collapsing when removing the second zones of the
titanium-containing metal layer.
DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a flow illustrating a method for manufacturing
fine-pitch bumps in accordance with a preferred embodiment of the
present invention.
[0005] FIGS. 2A to 2K are sectional schematic diagrams illustrating
a method for manufacturing fine-pitch bumps in accordance with a
preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0006] With reference to FIGS. 1 and 2A to 2K, a method for
manufacturing fine-pitch bumps in accordance with a preferred
embodiment of the present invention comprises the following steps
of: first, with reference to step 11 of FIG. 1 and FIG. 2A,
providing a silicon substrate 110 having a surface 111, a plurality
of bond pads 112 disposed at the surface 111 and a protective layer
113 disposed at the surface 111, wherein the protective layer 113
comprises a plurality of openings 113a, and the bond pads 112 are
revealed by the openings 113a; next, referring to step 12 of FIG. 1
and FIG. 2B, forming a titanium-containing metal layer 200 on the
silicon substrate 110, the titanium-containing metal layer 200
comprises a plurality of first zones 210 and a plurality of second
zones 220 located outside the first zones 210, the protective layer
113 and the bond pads 112 are covered with the titanium-containing
metal layer 200; thereafter, referring to step 13 of FIG. 1 and
FIG. 2C, forming a photoresist layer 300 on the titanium-containing
metal layer 200; afterwards, referring to step 14 of FIG. 1 and
FIG. 2D, patterning the photoresist layer 300 to form a plurality
of opening slots 310 corresponded to the first zones 210 of the
titanium-containing metal layer 200; then, referring to step 15 of
FIG. 1 and FIG. 2E, forming a plurality of copper bumps 120 at the
opening slots 310, each of the copper bumps 120 comprises a first
top surface 121 and a ring surface 122.
[0007] Next, referring to step 16 of FIG. 1 and FIG. 2F, heating
the photoresist layer 300 to ream the opening slots 310 of the
photoresist layer 300, and the heat process enables the photoresist
layer 300 to form a plurality of body portions 320 and a plurality
of removable portions 330, in this embodiment, the glass transition
temperature in the heat process ranges from 70 to 140 degrees;
afterwards, referring to step 17 of FIG. 1 and FIG. 2G, etching the
photoresist layer 300 to remove the removable portions 330 and
expose the titanium-containing metal layer 200, in this embodiment,
the method for etching the photoresist layer 300 can be a method of
plasma dry etching; thereafter, with reference to step 18 of FIG. 1
and FIG. 2H, forming a plurality of bump protection layers 130 on
the titanium-containing metal layer 200, the first top surface 121
and the ring surface 122 of each of the copper bumps 120, wherein
each of the bump protection layers 130 comprises a metallic
coverage portion 132 and a bump coverage portion 131 having a
second top surface 131a, the first top surface 121 and the ring
surface 122 of each of the copper bumps 120 are covered with the
bump coverage portion 131, in this embodiment, the material of the
bump protection layers 130 can be chosen from one of nickel,
palladium or gold.
[0008] Next, referring to step 19 of FIG. 1 and FIG. 2I, forming a
plurality of wettable layers 140 on the second top surfaces 131a of
the bump coverage portions 131; afterwards, referring to step 20 of
FIG. 1 and FIG. 2J, removing the body portions 320 of the
photoresist layer 300 to reveal the wettable layers 140 and the
bump protection layers 130; eventually, referring to step 21 of
FIG. 1 and FIG. 2K, removing the second zones 220 of the
titanium-containing metal layer 200 to enable each of the first
zones 210 of the titanium-containing metal layer 200 to form an
under bump metallurgy layer 150 located under each of the copper
bumps 120 therefore forming a fine-pitch bump structure 100,
wherein each of the under bump metallurgy layers 150 comprises a
bearing portion 151 located under each of the copper bumps 120 and
an extending portion 152 protruded to the ring surface 122 of each
of the copper bumps 120, the protective layer 113 is partly covered
with the extending portion 152 of the under bump metallurgy layers
150, and the extending portion 152 of each of the under bump
metallurgy layers 150 is covered with the metallic coverage portion
132 of each of the bump protection layers 130. The under bump
metallurgy layers 150 are made of a material selected from one of
titanium/tungsten/gold, titanium/copper and
titanium/tungsten/copper. In addition, in this embodiment, each of
the bump coverage portions 131 comprises a first outer lateral
surface 131b, wherein each of the metallic coverage portions 132 is
protruded to the first outer lateral surface 131b of the bump
coverage portion 131 and comprises a second outer lateral surface
132a. Furthermore, the extending portion 152 of each of the under
bump metallurgy layers 150 comprises a third outer lateral surface
152a coplanar with the second outer lateral surface 132a. The
copper bumps 120 being covered by the bump protection layers 130
may lower dissociation of copper ions released from the copper
bumps 120, which improves reliability of the fine-pitch bump
structure 100 effectively. Besides, the protection of the bump
protection layers 130 may prevent the copper bumps 120 from
collapsing when removing the second zones 220 of the
titanium-containing metal layer 200.
[0009] With reference to FIG. 2K again, a fine-pitch bump structure
100 in accordance with a preferred embodiment of the present
invention at least comprises a silicon substrate 110, a plurality
of under bump metallurgy layers 150, a plurality of copper bumps
120, a plurality of bump protection layers 130, and a plurality of
wettable layers 140, wherein the silicon substrate 110 comprises a
surface 111, a plurality of bond pads 112 disposed at the surface
111 and a protective layer 113 disposed at the surface 111. The
protective layer 113 comprises a plurality of openings 113a, and
the bond pads 112 are revealed by the openings 113a. The under bump
metallurgy layers 150 are formed on the bond pads 112, each of the
under bump metallurgy layers 150 comprises a bearing portion 151
and an extending portion 152, and the under bump metallurgy layers
150 are made of a material selected from one of
titanium/tungsten/gold, titanium/copper and
titanium/tungsten/copper. The copper bumps 120 are formed on the
under bump metallurgy layers 150, and each of the copper bumps 120
comprises a first top surface 121 and a ring surface 122. The
bearing portion 151 of each of the under bump metallurgy layers 150
is located under each of the copper bumps 120, and the extending
portion 152 of each of the under bump metallurgy layers 150 is
protruded to the ring surface 122 of each of the copper bumps 120.
The bump protection layers 130 are formed on the extending portions
152 of the under bump metallurgy layers 150, the first top surface
121 and the ring surface 122 of each of the copper bumps 120. Each
of the bump protection layers 130 comprises a metallic coverage
portion 132 and a bump coverage portion 131 having a second top
surface 131a, wherein the first top surface 121 and the ring
surface 122 of each of the copper bumps 120 are covered with each
of the bump coverage portions 131, and the extending portion 152 of
each of the under bump metallurgy layers 150 is covered with each
of the metallic coverage portions 132. In this embodiment, the
material of the bump protection layers 130 can be chosen from one
of nickel, palladium or gold. The wettable layers 140 are formed on
the second top surfaces 131a of the bump coverage portions 131. The
bump coverage portion 131 further comprises a first outer lateral
surface 131b, the metallic coverage portion 132 is protruded to the
first outer lateral surface 131b and comprises a second outer
lateral surface 132a, and the extending portion 152 of each of the
under bump metallurgy layers 150 comprises a third outer lateral
surface 152a coplanar with the second outer lateral surface
132a.
[0010] While this invention has been particularly illustrated and
described in detail with respect to the preferred embodiments
thereof, it will be clearly understood by those skilled in the art
that it is not limited to the specific features and describes and
various modifications and changes in form and details may be made
without departing from the spirit and scope of this invention.
* * * * *