US7279724B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ceramic substrate for a light emitting diode where the substrate incorporates ESD protection
Assignee: Lumileds LLC
•
Filing: 2004-02-25
•
Granted: 2007-10-09
•
Expires: 2024-02-25
Abstract
Abstract A metal oxide varistor comprising one or more zinc oxide layers is formed integral to a ceramic substrate to provide ESD protection of a semiconductor device mounted to the substrate. The portion of the ceramic substrate not forming the varistor may be aluminum oxide, aluminum nitride, silicon carbide, or boron nitride. The varistor portion may form any part of the ceramic substrate, including all of the ceramic substrate.
Inventors
- 👤 William David Collins, III
- 👤 Jerome Chandra Bhat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:27
CPC Classifications
H; H10; H10W; H10W90/00; H01; H01C; H01C7/00; H01C7/10; H01C7/105; H01C7/108; H01C7/112; H05; H05K; H05K1/00; H05K1/02; H05K1/0213; H05K1/0254; H05K1/0257; H05K1/0259; H10H; H10H20/00; H10H20/80; H10H20/85; H10H20/8506; H10W42/00; H10W42/60; H10W72/00; H10W72/071; H10W72/072; H10W72/07251; H10W72/20; H10W72/851; H10W72/874; H10W72/884; H10W74/00; H10W90/701; H10W90/721; H10W90/726; H10W90/731; H10W90/734; H10W90/751; H10W90/754; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49144; Y10T29/49147; Y10T29/49169; Y10T29/49171
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
207 words
A device comprising: a ceramic substrate having atop surface and a bottom surface, the top surface having at least one metal electrode Mr electrical connection to an electrode of an overlying semiconductor device, the ceramic substrate comprising a first area containing a first metal oxide, the first area forming a metal oxide varistor that provides electrostatic discharge (ESD) protection of a semiconductor device mounted over a top surface of the ceramic substrate, the ceramic substrate also comprising a second area containing a ceramic second material that does not contain any first metal oxide, the second area not forming a varistor. wherein the first metal oxide comprises zinc oxide, and wherein the-zinc oxide is located only around at least a portion of a periphery of the ceramic substrate, and the second area is located at a central portion of the ceramic substrate; metal pads on a top surface of the ceramic substrate for connection to the semiconductor device; metal electrodes for electrical connection to a printed circuit board; metal vias through the ceramic substrate for electrically connecting the metal pads to the metal electrodes; and the second material comprises one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and the first metal oxide comprises zinc oxide.
Claim 2
Independent Claim
207 words
A device comprising: a ceramic substrate having atop surface and a bottom surface, the top surface having at least one metal electrode Mr electrical connection to an electrode of an overlying semiconductor device, the ceramic substrate comprising a first area containing a first metal oxide, the first area forming a metal oxide varistor that provides electrostatic discharge (ESD) protection of a semiconductor device mounted over a top surface of the ceramic substrate, the ceramic substrate also comprising a second area containing a ceramic second material that does not contain any first metal oxide, the second area not forming a varistor. wherein the first metal oxide comprises zinc oxide, and wherein the-zinc oxide is located only around at least a portion of a periphery of the ceramic substrate, and the second area is located at a central portion of the ceramic substrate; metal pads on a top surface of the ceramic substrate for connection to the semiconductor device; metal electrodes for electrical connection to a printed circuit board; metal vias through the ceramic substrate for electrically connecting the metal pads to the metal electrodes; and the second material comprises one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and the first metal oxide comprises zinc oxide.
Claim 3
Independent Claim
160 words
A device comprising: a ceramic substrate having a top surface and a bottom surface, the top surface having at least one metal electrode for electrical connection to an electrode of an overlying semiconductor device, the ceramic substrate comprising a first area containing a first metal oxide, the first area forming a metal oxide varistor that provides electrostatic discharge (ESD) protection of a semiconductor device mounted over a top surface of the ceramic substrate, the ceramic substrate also comprising a second area containing a ceramic second material that does not contain any first metal oxide, the second area not forming a varistor, wherein the first metal oxide-comprises zinc oxide, and wherein the zinc oxide forms only a central portion of the ceramic substrate, and the second area surrounds the zinc oxide around a periphery of the ceramic substrate, wherein the second material comprises one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and the first metal oxide-comprises zinc oxide.
Claim 4
Independent Claim
160 words
A device comprising: a ceramic substrate having a top surface and a bottom surface, the top surface having at least one metal electrode for electrical connection to an electrode of an overlying semiconductor device, the ceramic substrate comprising a first area containing a first metal oxide, the first area forming a metal oxide varistor that provides electrostatic discharge (ESD) protection of a semiconductor device mounted over a top surface of the ceramic substrate, the ceramic substrate also comprising a second area containing a ceramic second material that does not contain any first metal oxide, the second area not forming a varistor, wherein the first metal oxide-comprises zinc oxide, and wherein the zinc oxide forms only a central portion of the ceramic substrate, and the second area surrounds the zinc oxide around a periphery of the ceramic substrate, wherein the second material comprises one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and the first metal oxide-comprises zinc oxide.
Claim 5
Dependent Claim
38 words
The device of claim 1 wherein zinc oxide is located on at least a portion of a top or bottom surface of the ceramic second material around at least a portion of a periphery of the ceramic substrate.
Claim 6
Dependent Claim
19 words
The device of claim 2 wherein the zinc oxide comprises a majority of the material in the ceramic substrate.
Claim 7
Dependent Claim
57 words
The device of claim 1 wherein the varistor comprises ceramic grains, and wherein the varistor comprises a plurality of metal layers sandwiching the ceramic grains, the metal layers being electrically connected to exposed substrate electrodes, the ceramic grains providing a low resistance pat between the metal layers when an ESD voltage is applied across the metal layers.
Claim 8
Dependent Claim
39 words
The device of claim 1 wherein the varistor comprises ceramic grains, the varistor further comprising multiple overlying metal layers with the ceramic grains between the metal layers, the metal layers being electrically connected to metal electrodes on the substrate.
Claim 9
Dependent Claim
70 words
The device of claim 1 wherein the varistor comprises ceramic grains forming a surface, and wherein the varistor comprises a plurality of metal layers electrically connected to exposed substrate electrodes, the plurality of metal layers being in physical contact with only a single surface of the ceramic grains, the ceramic grains providing a low resistance path between the metal layers when an ESD voltage is applied across the metal layers.
Claim 10
Dependent Claim
29 words
The device of claim 1 further comprising a light emitting diode (LED) chip mounted on the top surface of the substrate and being protected from ESD by the varistor.
Claim 11
Dependent Claim
30 words
The device of claim 2 wherein the varistor forms part of a heat conduction path between the semiconductor device and a printed circuit board over which the substrate is mounted.
Claim 12
Dependent Claim
139 words
The device of claim 1 wherein the ceramic substrate has a top and bottom surface comprising the second area, the second area comprising one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and wherein the varistor comprises zinc oxide formed as one or more layers fixed to the top or bottom surface of the ceramic substrate only around a periphery of the ceramic substrate, a first metal layer being formed to physically contact a top surface of the one or more layers, and a second metal layer being formed to physically contact a bottom surface of the one or more layers, the one or more layers providing a low resistance path between the first metal layer and the second metal layer when an ESD voltage is applied across the first metal layer and the second metal layer.
Claim 13
Dependent Claim
133 words
The device of claim 1 wherein the ceramic substrate has a top and bottom surface comprising the second area, the second area comprising one of aluminum oxide, aluminum nitride, silicon carbide, or boron nitride, and wherein the varistor comprises zinc oxide formed as a single layer fixed to the top or bottom surface of the ceramic substrate only around a periphery of the ceramic substrate, a first metal layer being formed to physically contact a first surface of the single layer, and a second metal layer being formed to also physically contact the first surface of the single layer, the single layer providing a low resistance path between the first metal layer and the second metal layer when an ESD voltage is applied across the first metal layer and the second metal layer.
Claim 14
Dependent Claim
34 words
The device of claim 2 further comprising metal pads on a top surface of the ceramic substrate, for connection to the semiconductor device, and metal electrodes for electrical connection to a printed circuit board.
Claim 15
Dependent Claim
23 words
The device of claim 12 further comprising metal vias through the ceramic substrate for electrically connecting the metal pads to the metal electrodes.
Claim 16
Dependent Claim
26 words
The device of claim 12 wherein the metal pads are electrically connected to the metal electrodes by metal portions over a periphery of the ceramic substrate.
Claim 17
Dependent Claim
23 words
The device of claim 1 wherein the semiconductor device comprises a semiconductor chip directly affixed to the top suffice of the ceramic substrate.
References Cited (Backward Citations)
US3679950A
Cited
US3725836A
Cited
US3965552A
Cited
US4506285A
Cited
US5290375A
Cited
US5176772A
Cited
US5235310A
Cited
US5540884A
Cited
US5874378A
Cited
US6217990B1
Cited
US6339367B1
Cited
US6535105B2
Cited
US20010043454A1
Cited
US20030043013A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2010-10-08 | 2011-04-09 | 2011-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2014-10-08 | 2015-04-09 | 2015-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2018-10-08 | 2019-04-09 | 2019-10-09 | $7700.00 | Window Closed / Lapsed |