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US5508561A Expired / Lapsed US ⏱️ 0.0 years remaining

Apparatus for forming a double-bump structure used for flip-chip mounting

Assignee: NEC Corp
•
Filing: 1994-11-14
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Granted: 1996-04-16
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Expires: 2014-11-14
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Abstract

Abstract A bump structure has a bump constituted by a metal projection which is formed on an electrode of a substrate, and a solder which covers the metal projection but does not touch the electrode. The metal projection is substantially spherical and has a projected portion at a center portion on an upper surface thereof. The metal projection is made of a metal having properties of solder diffusion prevention and adhesion to solder. The bump structure may have two bumps, the first bump being substantially the same as the bump described above and the second being such that its diameter is smaller than an outer diameter of the first bump and it covers the projected portion on the first bump. This bump structure can be formed using a simple process, and can be applied to flip-chip mounting in semiconductor devices with high reliability and yield.

Inventors

  • 👤 Masamoto Tago
  • 👤 Kei Tanaka

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 10:26
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/20; H10W72/01; H10W72/012; H10W72/01215; H10W72/01221; H10W72/01225; H10W72/01251; H10W72/01255; H10W72/071; H10W72/072; H10W72/07231; H10W72/07236; H10W72/241; H10W72/251; H10W72/252; H10W72/255; H10W72/50; H10W72/551; H10W72/552; H10W72/5522

Claims Analysis

Total Claims: 24
Claim 1
Independent Claim 117 words
A bump structure comprising: a first bump made of a conductive material, a first surface of which is fixed to an electrode of a substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof; said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material having a diameter less than that of said first bump, and covering said projected portion on said first bump, but not touching said electrode; said first bump being made of a metal having properties of preventing said second bump from diffusing and of adhering to said second bump.
Claim 2
Dependent Claim 117 words
A bump structure comprising: a first bump made of a conductive material, a first surface of which is fixed to an electrode of a substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof; said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material having a diameter less than that of said first bump, and covering said projected portion on said first bump, but not touching said electrode; said first bump being made of a metal having properties of preventing said second bump from diffusing and of adhering to said second bump.
Claim 3
Dependent Claim 26 words
The bump structure according to claim 1, in which said first bump has a cylindrical projected portion at the center portion on the second surface thereof.
Claim 4
Dependent Claim 26 words
The bump structure according to claim 1, in which said first bump has a conical projected portion at the center portion on the second surface thereof.
Claim 5
Dependent Claim 32 words
The bump structure according to claim 1, in which said first bump is made of a material selected from the group consisting of copper and a metal whose main composition is copper.
Claim 6
Dependent Claim 32 words
The bump structure according to claim 1, in which said first bump is made of a material selected from the group consisting of palladium and a metal whose main composition is palladium.
Claim 7
Dependent Claim 24 words
The bump structure according to claim 1, in which said second bump has a diameter smaller than an outer diameter of said first bump.
Claim 8
Dependent Claim 100 words
A bump structure comprising: a first bump made of a conductive material, a first surface of which is fixed to an electrode of a substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof; said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material, and covering said projected portion on said first bump, but not touching said electrode; wherein said second bump has the diameter which is 40%-80% of the diameter of said first bump.
Claim 9
Dependent Claim 100 words
A bump structure comprising: a first bump made of a conductive material, a first surface of which is fixed to an electrode of a substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof; said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material, and covering said projected portion on said first bump, but not touching said electrode; wherein said second bump has the diameter which is 40%-80% of the diameter of said first bump.
Claim 10
Dependent Claim 16 words
The bump structure according to claim 1, in which said second bump is made of solder.
Claim 11
Dependent Claim 18 words
The bump structure according to claim 1, in which said second bump is made of conductive resin material.
Claim 12
Dependent Claim 25 words
The bump structure according to claim 1, in which said electrode is made of one of an aluminum electrode and an aluminum compound metal electrode.
Claim 13
Dependent Claim 15 words
The bump structure according to claim 1, in which said substrate is a semiconductor chip.
Claim 14
Dependent Claim 127 words
A flip-chip connecting structure comprising: a first bump made of a conductive material, a first surface of which is fixed to a first electrode of a first substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof, said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material having a diameter less than that of said first bump, and being configured such that it interconnects said second electrode and said first bump but does not touch said first electrode; said first bump being made of a metal having properties of preventing said second bump from diffusing and of adhering to said second bump.
Claim 15
Dependent Claim 127 words
A flip-chip connecting structure comprising: a first bump made of a conductive material, a first surface of which is fixed to a first electrode of a first substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof, said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material having a diameter less than that of said first bump, and being configured such that it interconnects said second electrode and said first bump but does not touch said first electrode; said first bump being made of a metal having properties of preventing said second bump from diffusing and of adhering to said second bump.
Claim 16
Dependent Claim 27 words
The flip-chip connecting structure according to claim 12, in which said first bump has a cylindrical projected portion at the center portion on the second surface thereof.
Claim 17
Dependent Claim 27 words
The flip-chip connecting structure according to claim 12, in which said first bump has a conical projected portion at the center portion on the second surface thereof.
Claim 18
Dependent Claim 33 words
The flip-chip connecting structure according to claim 12, in which said first bump is made of a material selected from the group consisting of copper and a metal whose main composition is copper.
Claim 19
Dependent Claim 33 words
The flip-chip connecting structure according to claim 12, in which said first bump is made of a material selected from the group consisting of palladium and a metal whose main composition is palladium.
Claim 20
Dependent Claim 25 words
The flip-chip connecting structure according to claim 12, in which said second bump has a diameter smaller than an outer diameter of said first bump.
Claim 21
Dependent Claim 110 words
A flip-chip connecting structure comprising: a first bump made of a conductive material, a first surface of which is fixed to a first electrode of a first substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof, said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material, and being configured such that it interconnects said second electrode and said first bump but does not touch said first electrode; wherein said second bump has the diameter which is 40%-80% of the diameter of said first bump.
Claim 22
Dependent Claim 110 words
A flip-chip connecting structure comprising: a first bump made of a conductive material, a first surface of which is fixed to a first electrode of a first substrate, and which is substantially spherical and has a projected portion at a center portion on a second surface thereof, said second surface being on the opposite side of said first bump from said first surface; and a second bump made of a conductive material, and being configured such that it interconnects said second electrode and said first bump but does not touch said first electrode; wherein said second bump has the diameter which is 40%-80% of the diameter of said first bump.
Claim 23
Dependent Claim 17 words
The flip-chip connecting structure according to claim 12, in which said second bump is made of solder.
Claim 24
Dependent Claim 19 words
The flip-chip connecting structure according to claim 12, in which said second bump is made of conductive resin material.

References Cited (Backward Citations)

US4000842A Cited
US4263606A Cited
US4742023A Cited
US4818728A Cited
US4970571A Cited
JPH01143291A Cited
US5289631A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1999-04-16 1999-10-16 2000-04-16 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2003-04-16 2003-10-16 2004-04-16 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2007-04-16 2007-10-16 2008-04-16 $7700.00 Window Closed / Lapsed

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