Method of plating manufacturing a temperature-triggered fuse device
11120964 · 2021-09-14
Assignee
Inventors
Cpc classification
Y10T29/49107
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01H2085/0412
ELECTRICITY
Y10T29/49117
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01H37/761
ELECTRICITY
International classification
H01R43/00
ELECTRICITY
H01H37/76
ELECTRICITY
Abstract
A novel temperature-triggered fuse device is configured to be activated at a designer-specified ambient temperature by utilizing wetting force among a pair of wetting material bays and a solder bridge or a solder ball. The solder bridge or the solder ball is typically positioned on top of the pair of wetting material bays separated by an electrically-insulated gap. Preferably, the wetting material bays are at least partly made of gold, nickel, or other elements suitable for generating an increased wetting force to the solder bridge or the solder ball upon increases in ambient temperature. The novel temperature-triggered fuse device can be integrated into various types of integrated circuits (IC's), or can function as a discrete fuse connected to one or more electronic components for robust protection from power surges and/or thermal runaway-related device malfunctions, meltdowns, or explosions. Various methods of producing the temperature-triggered fuse device are also disclosed herein.
Claims
1. A plating manufacturing method for producing a temperature-triggered fuse device, the plating manufacturing method comprising the steps of: sputtering a base seed layer on top of a base substrate; applying a photoresist on the base seed layer; forming patterns on the photoresist by utilizing a photomask, wherein the patterns identify a first piece of the base seed layer and a second piece of the base seed layer, which are separated by a gap; plating a first metal pad on the first piece of the base seed layer and a second metal pad on the second piece of the base seed layer; etching areas not covered by the photoresist to remove corresponding underlying portions of the base seed layer; cleaning the areas and removing photoresist residues after etching; depositing a de-wetting material coating on a topmost surface; applying a passivation mask to identify metal exposure locations on the first metal pad and the second metal pad for removal of the de-wetting material coating; etching the de-wetting material coating from the metal exposure locations; cleaning the metal exposure locations; depositing a wetting bay seed layer on the topmost surface; applying a gap mask to identify the gap separating the first piece of the base seed layer and the second piece of the base seed layer for removal of a portion of the wetting bay seed layer above the gap; etching the portion of the wetting bay seed layer above the gap; applying a solder bridge mask to identify a solder bridge location; plating solder to form the solder bridge at the solder bridge location across the gap, wherein the solder bridge connects separated pieces of the wetting bay seed layer; and etching portions of the wetting bay seed layer above the de-wetting material coating.
2. The plating manufacturing method of claim 1, wherein the wetting bay seed layer is made of gold, nickel, copper, or a combination thereof.
3. The plating manufacturing method of claim 1, wherein the de-wetting material coating is made of polymer films.
4. The plating manufacturing method of claim 1, wherein the first metal pad and the second metal pad are made of aluminum or copper.
5. The plating manufacturing method of claim 1, wherein the base substrate is silicon, silicon dioxide, or a printed circuit board.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DETAILED DESCRIPTION
(8) Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.
(9) In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
(10) The detailed description is presented largely in terms of description of shapes, configurations, and/or other symbolic representations that directly or indirectly resemble a novel chip structure and/or a manufacturing method for a temperature-triggered fuse device. These descriptions and representations are the means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art.
(11) Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. Furthermore, separate or alternative embodiments are not necessarily mutually exclusive of other embodiments. Moreover, the order of blocks in process flowcharts or diagrams representing one or more embodiments of the invention do not inherently indicate any particular order nor imply any limitations in the invention.
(12) For the purpose of describing the invention, a term described herein as a “fuse” or a “fuse device” is defined as a special-purpose apparatus, which is designed to protect a circuit or another electronic component from malfunctions or damages due to undesirable power surges and/or thermal runaways. A fuse may be an integrated electronic component to an integrated circuit (IC's) or a discrete component operatively connected to IC's or other electronic components.
(13) Moreover, for the purpose of describing the invention, a term described herein as “wetting force” is defined as a net pulling or pushing force resulting from intermolecular interactions among one or more wetting materials and a solder bridge or a solder ball at varying temperatures. In a preferred embodiment of the invention, as ambient temperature increases to a threshold temperature for activating a temperature-triggered fuse, the wetting force generated by intermolecular tensions among wetting material(s) (e.g. gold (Au), nickel gold (Ni/Au), copper gold (Cu/Au)) on a metallic substrate and a solder bridge or a solder ball, which connects a pair of wetting materials separated by an air gap, becomes sufficiently strong enough to break off the solder bridge or the solder ball.
(14) Furthermore, for the purpose of describing the invention, a term described herein as a “solder bridge” or a “solder ball” is defined as a temperature-specific breakable electrical connection element between a first wetting material bay and a second wetting material bay. Typically, a solder bridge or a solder ball is positioned above an air gap, which is configured to contain broken solder bridge or solder ball pieces when the solder bridge or the solder ball breaks apart due to an increased wetting force at a threshold temperature.
(15) In addition, for the purpose of describing the invention, a term described herein as “power surge” or “power surge event” is defined as a spike in voltage, current, or both. An example of a power surge is a voltage or current spike at an input terminal of an electrical device caused by an external power source, an external electrical signal, or a sudden change in environment such as lightening or ESD discharging.
(16) One aspect of an embodiment of the present invention is providing a novel electronic component structure as a novel fuse device. The novel fuse device is configured to provide real-time temperature-triggered circuit and device protection at a specified ambient temperature near the novel fuse device.
(17) Another aspect of an embodiment of the present invention is providing an IC integration-friendly temperature-triggered fuse device that can be easily incorporated into a variety of integrated circuits, circuit boards, and electrical device casings.
(18) In addition, another aspect of an embodiment of the present invention is providing one or more novel device fabrication steps and methods for manufacturing a temperature-triggered fuse device.
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(20) Furthermore, a first metal pad (113) and a second metal pad (115) are positioned on top of the base substrate (101), as shown in
(21) Continuing with
(22) In addition, the novel temperature-triggered fuse device in accordance with the preferred embodiment of the invention also includes an electrically-insulating material (102) and an electrically-insulated gap (117) that physically separate the first metal pad (113) from the second metal pad (115). In some embodiments of the invention, the electrically-insulating material (102) may be a film made of the same chemical compound utilized for the first de-wetting material (109) and the second de-wetting material (111). In other embodiments, the electrically-insulating material (102) may be a specialized dielectric substance that is chemically distinct from other de-wetting materials in the novel temperature-triggered fuse device. In addition, the electrically-insulated gap (117) is preferably an air gap. In some other embodiments, other gasses, liquids, or solids with high electrical insulation properties may be utilized in the electrically-insulated gap (117).
(23) Furthermore, the novel temperature-triggered fuse device also includes the solder bridge (105), which physically and electrically connects the first wetting material bay (103) and the second wetting material bay (107) across the electrically-insulated gap (117). In the preferred embodiment of the invention, the solder bridge (105) is designed to break apart, melt, and/or separate into multiple fragments when the wetting force generated by the first wetting material bay (103) and the second wetting material bay (107) is increased enough (i.e. due to a rising ambient temperature) to result in a sufficient net pulling or pushing force on the solder bridge (105) for structural breakage.
(24) In context of the embodiment of the invention as shown in
(25) Furthermore, in some embodiments of the invention, designing the temperature-triggered fuse device requires a calculated amount of solder volume, a calculated dimension of a solder ball or a solder bridge, a calculated size of the gap, and a calculated dimension of each wetting material bay to ensure a desirable structural disconnection at a desired threshold temperature.
(26) In one example, a fuse designer may contemplate the following design considerations when estimating appropriate dimensions for certain components contained in the temperature-triggered fuse device:
(27) The overlap between the solder bridge and the bay on each side of the gap: Ws
(28) Gap width: Wg, Gap length: lg, Solder thickness of the bridge at the gap: ts
(29) Solder volume contained in the bridge structure: Vsg=(2Ws+Wg)*lg*ts
(30) Upon melting, this volume will divide between the two bays
(31) Thus, volume of solder on each bay: Vsg/2=(2Ws+Wg)*lg*ts/2
(32) If Ws=50 microns, Wg=50 microns, lg=100 microns, ts=70 microns,
(33) Then, Vsg=5.25×10{circumflex over ( )}5
(34) If the solder ball on each bay (after melting) is to have a height of 40 microns, then the area of the bay can be estimated as:
(35) Abay=13,125.00 square microns.
(36) Thus, if each bay were to be a square shape, the length of each side, Lbay=114.56 microns.
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(38) Furthermore, as also shown in the top view (200) in
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(40) In a preferred embodiment of the invention, materials or compounds utilized for the formation of the wetting material bays are purposefully selected to generate a specific amount of wetting force on the solder bridge for breakage at a predefined ambient threshold temperature. For example, if a fuse designer intends to activate the novel temperature-triggered fuse device for electrical disconnection at 120 degree Celsius, then the fuse designer may specify a particular mixture of gold (Au) and nickel (Ni) for the wetting material bays to generate sufficient wetting force to break the solder bridge at or above 120 degree Celsius. Furthermore, the fuse designer may also choose to modify the dimensions (i.e. thickness, length, width, or height) of the solder bridge to enable a precise temperature-triggered fuse activation at a desired ambient threshold temperature level.
(41) In context of the embodiment of the invention as shown in
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(43) In context of the embodiment of the invention as shown in
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(45) Moreover, as shown in
(46) Furthermore, as shown in
(47) Finally, as shown in
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(49) Then, as shown in
(50) The third step (600C) of this embodiment involves depositing a de-wetting material coating on a topmost surface, and applying a passivation mask to identify metal exposure locations on the first metal pad (607) and the second metal pad (609) for removal of the de-wetting material coating. Then, the de-wetting material coating from the metal exposure locations is etched away to create a device structure that has a first piece (613) of the de-wetting material coating covering an outer perimeter of the first metal pad (607), and a second piece (615) of the de-wetting material coating covering an outer perimeter of the second metal pad (609), as shown in
(51) Then, the fourth step (600D) of this embodiment involves depositing a wetting bay seed layer on the topmost surface of the device structure, and applying a gap mask to identify the gap separating the first piece (603A) of the base seed layer and the second piece (603B) of the base seed layer for removal of a portion of the wetting bay seed layer above the gap (611). Subsequently, the portion of the wetting bay seed layer above the gap (611) is etched away, which creates a first piece (617) of the wetting bay seed layer and a second piece (619) of the wetting bay seed layer, as shown in
(52) The fifth step (600E) of this embodiment involves plating solder to form the solder bridge (625) at the solder bridge location across the gap (611), wherein the solder bridge (625) connects separated pieces (617, 619) of the wetting bay seed layer, as shown in
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(54) Then, a first de-wetting material coating (703) is deposited on an outer portion of the first aluminum pad, and a second de-wetting material coating (707) is deposited on an outer portion of the second aluminum pad. The first de-wetting material coating (703) and the second de-wetting material coating (707) can be made of same materials, such as polymer films. In addition, an electrically-insulating material (702) is also deposited between the first aluminum pad and the second aluminum pad, as shown in
(55) Furthermore, as shown in
(56) Finally, as shown in
(57) Various embodiments of a temperature-triggered fuse device and related methods of manufacturing the device have been illustrated in
(58) In contrast, the novel temperature-triggered fuse device disclosed in various embodiments of the present invention accurately tracks a rise in ambient temperature near the location of the fuse, and the fuse is rapidly triggered to disconnect the fuse-enabled circuitry and electronic components when the rise in ambient temperature meets or exceeds the specified ambient threshold temperature. Furthermore, a fuse designer is able to precisely define a desired ambient threshold temperature by customizing material selection and mix for the wetting material bays and by fine-tuning the dimensions of a solder bridge or a solder ball, which is utilized to connect a pair of wetting material bays.
(59) Furthermore, the novel temperature-triggered fuse device disclosed in various embodiments of the present invention can be readily integrated into conventional IC designs, and various manufacturing steps disclosed herein for production of the novel temperature-triggered fuse device enable easy integration of this novel fuse design into many different types of IC's, discrete components, and other electronic devices.
(60) While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.