BUMPING PROCESS AND STRUCTURE THEREOF
A bumping process includes providing a silicon substrate; forming a titanium-containing metal layer on silicon substrate, the titanium-containing metal layer comprises a plurality of first areas and a plurality of second areas; forming a first photoresist layer on titanium-containing metal layer; patterning the first photoresist layer to form a plurality of first opening slots; forming a plurality of copper bumps within first opening slots, said copper bump comprises a first top surface and a first ring surface; removing the first photoresist layer; forming a second photoresist layer on titanium-containing metal layer; patterning the second photoresist layer to form a plurality of second opening slots; forming a plurality of bump isolation layers at spaces, the first top surfaces and the first ring surfaces; forming a plurality of connective layers on bump isolation layers; removing the second photoresist layer, removing the second areas to form an under bump metallurgy layer.
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The present invention is generally related to a bumping process and structure thereof, which particularly relates to the bumping process which improves manufacturing yield.
BACKGROUND OF THE INVENTIONModern electronic products gradually lead a direction of light, thin, short, and small. Accordingly, the layout density of interior circuit for electronic product becomes more concentrated consequentially. However, a short distance between two adjacent electronic connection devices makes a short phenomenon easily occurred in circuit layout.
SUMMARYThe primary object of the present invention is to provide a bumping process comprising the steps of providing a silicon substrate having a surface, a plurality of bond pads disposed on said surface, and a protective layer disposed on said 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, said titanium-containing metal layer covers the protective layer and the bond pads and comprises a plurality of first areas and a plurality of second areas located outside the first areas; forming a first photoresist layer on the titanium-containing metal layer; patterning the first photoresist layer to form a plurality of first opening slots, wherein each of the first opening slots is corresponded to each of the first areas of the titanium-containing metal layer; forming a plurality of copper bumps within the first opening slots, each of the copper bumps comprises a first top surface and a first ring surface; removing the first photoresist layer to reveal the first top surfaces of the copper bumps, the first ring surfaces, and the second areas of the titanium-containing metal layer; forming a second photoresist layer on the titanium-containing metal layer and covering the copper bumps with the second photoresist layer; patterning the second photoresist layer to form a plurality of second opening slots, wherein each of the second opening slots is corresponded to each of the copper bumps and comprises an inner lateral surface, and a space located between the inner lateral surface of each of the second opening slots and the first ring surface of each of the copper bumps; forming a plurality of bump isolation layers at the spaces, the first top surfaces and the first ring surfaces, and each of the bump isolation layers comprises a second top surface; forming a plurality of connective layers on the second top surfaces of the bump isolation layers; removing the second photoresist layer; removing the second areas of the titanium-containing metal layer and enabling each of the first areas of the titanium-containing metal layer to form an under bump metallurgy layer located beneath the copper bump. Owning to the reason that each of the bump isolation layers covers the first ring surface and the first top surface of each of the copper bumps, a short phenomenon occurred between two adjacent copper bumps via dissociation of copper ions can be prevented. Therefore, the distance between two adjacent copper bumps can be reduced so as to increase the circuit layout density.
With reference to FIGS. 1 and 2A-2L, a bumping process in accordance with a preferred embodiment of the present invention comprises the steps described as followed. First, referring to step 10 of
Next, with reference to step 17 of
Referring to
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.
Claims
1. A bumping process at least comprising:
- providing a silicon substrate having a surface, a plurality of bond pads disposed on said surface, and a protective layer disposed on said 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, said titanium-containing metal layer covers the protective layer and the bond pads, and said titanium-containing metal layer comprises a plurality of first areas and a plurality of second areas located outside the first areas;
- forming a first photoresist layer on the titanium-containing metal layer;
- patterning the first photoresist layer to form a plurality of first opening slots, wherein each of the first opening slots is corresponded to each of the first areas of the titanium-containing metal layer;
- forming a plurality of copper bumps within the first opening slots, wherein each of the copper bumps comprises a first top surface and a first ring surface;
- removing the first photoresist layer to reveal the first top surfaces of the copper bumps, the first ring surfaces, and the second areas of the titanium-containing metal layer;
- forming a second photoresist layer on the titanium-containing metal layer and covering the copper bumps with the second photoresist layer;
- patterning the second photoresist layer to form a plurality of second opening slots, wherein each of the second opening slots is corresponded to each of the copper bumps and comprises an inner lateral surface, and a space located between the inner lateral surface of each of the second opening slots and the first ring surface of each of the copper bumps;
- forming a plurality of bump isolation layers at the spaces, the first top surfaces and the first ring surfaces of each of the copper bumps, and each of the bump isolation layers comprises a second top surface;
- forming a plurality of connective layers on the second top surfaces of the bump isolation layers;
- removing the second photoresist layer; and
- removing the second areas of the titanium-containing metal layer and enabling each of the first areas of the titanium-containing metal layer to form an under bump metallurgy layer located beneath the copper bump.
2. The bumping process in accordance with claim 1, wherein the protective layer further comprises an exposing surface, each of the bump isolation layers further comprises a bottom surface, and an interval is located between the exposing surface and the bottom surface.
3. The bumping process in accordance with claim 1, wherein each of the under bump metallurgy layers comprises a second ring surface having a first outer circumference, each of the bump isolation layers comprises a third ring surface having a second outer circumference, and the second outer circumference is not smaller than the first outer circumference.
4. The bumping process in accordance with claim 1, wherein each of the under bump metallurgy layers comprises a second ring surface, each of the first ring surfaces and each of the second ring surfaces are coplanar.
5. The bumping process in accordance with claim 3, wherein each of the under bump metallurgy layers comprises a second ring surface, each of the first ring surfaces and each of the second ring surfaces are coplanar.
6. The bumping process in accordance with claim 1, wherein the material of the under bump metallurgy layers can be selected from one of titanium/tungsten/gold, titanium/copper or titanium/tungsten/copper.
7. The bumping process in accordance with claim 1, wherein the material of the connective layers can be gold.
8. The bumping process in accordance with claim 1, wherein the material of the bump isolation layers can be chosen from one of nickel, palladium, gold or alloy of mentioned metals.
9. A bump structure at least includes:
- a silicon substrate having a surface, a plurality of bond pads disposed on the surface, and a protective layer disposed on the surface, wherein the protective layer comprises 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;
- a plurality of copper bumps formed on the under bump metallurgy layers, and each of the copper bumps comprises a first top surface and a first ring surface;
- a plurality of bump isolation layers, wherein each of the bump isolation layers covers the first top surface and the first ring surface of each of the copper bumps and comprises a second top surface, wherein, after an etching process is performed to remove part of each of the under bump metallurgy layers which is not located under each of the copper bumps, a slot is thereby formed between the protective layer and each of the bump isolation layers and each of the under bump metallurgy layers is surrounded by the slot; and
- a plurality of connective layers formed on the second top surfaces of the bump isolation layers.
10. The bump structure in accordance with claim 9, wherein the protective layer further comprises an exposing surface, each of the bump isolation layers further comprises a bottom surface, and an interval located between the exposing surface and the bottom surface.
11. The bump structure in accordance with claim 9, wherein each of the under bump metallurgy layers comprises a second ring surface having a first outer circumference, each of the bump isolation layers comprises a third ring surface having a second outer circumference, and the second outer circumference is not smaller than the first outer circumference.
12. The bump structure in accordance with claim 9, wherein each of the under bump metallurgy layers comprises a second ring surface, each of the first ring surfaces and each of the second ring surfaces are coplanar.
13. The bump structure in accordance with claim 11, wherein each of the under bump metallurgy layers comprises a second ring surface, each of the first ring surfaces and each of the second ring surfaces are coplanar.
14. The bump structure in accordance with claim 9, wherein the material of the under bump metallurgy layers is selected from one of titanium/tungsten/gold, titanium/copper or titanium/tungsten/copper.
15. The bump structure in accordance with claim 9, wherein the material of the connective layers is gold.
16. The bump structure in accordance with claim 9, wherein the material of the bump isolation layers is chosen from one of nickel, palladium, gold or alloy of mentioned metals.
Type: Application
Filed: Feb 1, 2012
Publication Date: Aug 1, 2013
Applicant: CHIPBOND TECHNOLOGY CORPORATION (Hsinchu)
Inventors: Chih-Ming Kuo (Hsinchu County), Yie-Chuan Chiu (Hsinchu City), Lung-Hua Ho (Hsinchu City)
Application Number: 13/363,479
International Classification: H01L 23/498 (20060101); H01L 21/768 (20060101);