DIKE AS EPOXY SQUEEZE OUT BARRIER IN FUSE DEVICES

A dike as an epoxy squeeze out barrier in a fuse device is provided. The fuse device can include first and second layers of laminate material, a cavity formed by central openings of the first and second layers of the laminate material, a fuse element that is supported by at least one of the first and second layers of the laminate material and traverses the cavity, an adhesive located on at least one of the first and second layers of the laminate material for bonding thereof, and a dike located on at least one of the first and second layers of the laminate material and surrounding a circumference of the cavity. When the first and second layers of the laminate material, the fuse element, the adhesive, and the dike are pressed together during manufacture, the dike can prevent the adhesive from flowing into the cavity.

FIELD

The present disclosure generally relates to fuse devices. More particularly, the present disclosure relates to a dike as an epoxy squeeze out barrier in fuse devices.

BACKGROUND

Many fuse devices use epoxy or another adhesive to bond layers thereof. However, when the layers of the fuse devices and the epoxy are pressed together during manufacture, the epoxy can squeeze out from between the layers, which can cause operational problems. For example, as seen inFIG.1, in a fuse device that includes a laminate material102, such as FR4, with a cavity106for a fuse element, such as a wire-in-air (WIA), the epoxy104can be placed on top of, below, and/or in between layers of the laminate material102for bonding thereof. However, when the layers of the laminate material102and the epoxy104are pressed together during manufacture, the epoxy104can squeeze out from between the layers of the laminate material102and into the cavity106, as shown by the arrows inFIG.1designating the flow of the epoxy104.

Such squeeze out can cause restrike failure during a short circuit event and/or product reliability issues. Indeed, when the epoxy104seeps into the cavity106, the epoxy can come into contact with the fuse element, thereby causing element corrosion. Furthermore, when the epoxy104seeps into the cavity106, an effective volume of the cavity106for the fuse element can be reduced, thereby leading to nuisance openings. Any time the epoxy104seeps into the cavity106, energy loss that can lead to overload failures as a result of the fuse element not meeting required opening time criteria can occur and/or a current overload or a short circuit failure due to a burned fuse can occur. In this regard, heat coming from a current overload or a short circuit event that is used to melt the fuse element and enact fuse functionality can be lost through dissipation or by altering ideal conditions that promote or favor enhanced functionality, such as, for example, the effective volume of the cavity106.

In view of the above, there is a continuing, ongoing need for an apparatus and a method to prevent epoxy squeeze out in fuse devices.

BRIEF SUMMARY

This Brief Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Brief Summary is not intended to identify key features or essential features of claimed subject matter or intended as an aid in determining scope of the claimed subject matter.

In some embodiments, an apparatus in accordance with the present disclosure can include a first layer of laminate material, a second layer of the laminate material, a cavity formed by central openings of the first layer of the laminate material and the second layer of the laminate material, a fuse element that is supported by at least one of the first layer of the laminate material and the second layer of the laminate material and traverses the cavity, an adhesive located on at least one of the first layer of the laminate material and the second layer of the laminate material for bonding thereof, and a dike located on at least one of the first layer of the laminate material and the second layer of the laminate material and surrounding a circumference of the cavity. When the first layer of the laminate material, the second layer of the laminate material, the fuse element, the adhesive, and the dike are pressed together during manufacture, the dike can prevent the adhesive from flowing into the cavity.

In some embodiments, the dike can include a non-conductive material.

In some embodiments, the dike can include a photo-imageable material, a liquid photo-imageable ink, a film, a coating, or a mask.

In some embodiments, the adhesive can flow away from the cavity and the dike when the first layer of the laminate material, the second layer of the laminate material, the fuse element, the adhesive, and the dike are pressed together during manufacture.

In some embodiments, the dike can include a slot or a canal on opposing ends of the dike for holding or guiding the fuse element.

In some embodiments, the apparatus can include a clearance between the adhesive and the dike or between the cavity and the dike.

In some embodiments, the adhesive material can spread into the clearance when the first layer of the laminate material, the second layer of the laminate material, the fuse element, the adhesive, and the dike are pressed together during manufacture.

In some embodiments, a method in accordance with the present disclosure can includes supporting a fuse element by at least one of a first layer of laminate material or a second layer of the laminate material with the fuse element traversing a cavity formed by central openings of the first layer of the laminate material and the second layer of the laminate material, forming a dike on at least one of the first layer of the laminate material or the second layer of the laminate material between the first layer of the laminate material and the second layer of the laminate material with the dike surrounding the cavity, bonding the first layer of the laminate material and the second layer of the laminate material with an adhesive located on at least one of the first layer of the laminate material and the second layer of the laminate material, pressing the first layer of the laminate material, the second layer of the laminate material, the fuse element, the adhesive, and the dike together during manufacture, and preventing the adhesive from flowing into the cavity with the dike.

In some embodiments, the method can include flowing the adhesive away from the cavity and the dike.

In some embodiments, the method can include holding or guiding the fuse element with a slot or a canal on opposing ends of the dike.

In some embodiments, the method can include spreading the adhesive material into a clearance between the adhesive and the dike or between the cavity and the dike.

In some embodiments, the method can include lowering an original thickness of the dike or the adhesive material to a reduced thickness.

In some embodiments, the method can include placing a photo-imageable film on at least one of the first layer of the laminate material or the second layer of the laminate material, placing a transparent film with an artwork pattern on the photo-imageable film, exposing the artwork pattern to cure a portion of the photo-imageable film underneath the transparent film, removing the transparent film, and dissolving uncured portions of the photo-imageable film while leaving the portion of the photo-imageable film that was cured to create the dike.

In some embodiments, the method can include spraying a liquid photo-imageable ink (LPI) on at least one of the first layer of the laminate material or the second layer of the laminate material, placing a transparent film with an artwork pattern on the LPI, exposing the artwork pattern to cure a portion of the LPI underneath the transparent film, removing the transparent film, and dissolving uncured portions of the LPI while leaving the portion of the LPI that was cured to create the dike.

In some embodiments, the method can include curing the LPI at low temperatures to partially dry the LPI prior to placing the transparent film on the LPI.

In some embodiments, the method can include placing a screen print or a stencil on at least one of the first layer of the laminate material or the second layer of the laminate material, depositing a liquid photo-imageable ink (LPI) on the screen print or the stencil with the LPI seeping through an aperture of the screen print or the stencil and onto at least one of the first layer of the laminate material or the second layer of the laminate material, removing the screen print or the stencil, and curing the LPI on the first layer of the laminate material or the second layer of the laminate material to create the dike.

In some embodiments, an apparatus can include a layer of laminate material, a cavity formed by an internal cut-out of the layer of the laminate material, an adhesive located on the layer of the laminate material, and a dike located on the layer of the laminate material and surrounding a circumference of the cavity. The dike can control a flow of the adhesive.

In some embodiments, the dike can include a slot or a canal on opposing ends of the dike.

In some embodiments, the apparatus can include a clearance between the adhesive and the dike or between the cavity and the dike.

In some embodiments, when the layer of the laminate material, the adhesive, and the dike are pressed together during manufacture, the dike can prevent the adhesive from flowing into the cavity.

DETAILED DESCRIPTION

Exemplary embodiments of a dike as an epoxy squeeze out barrier in accordance with the present disclosure will now be described more fully hereinafter with reference made to the accompany drawings. The dike as an epoxy squeeze out barrier may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will convey certain exemplary aspects of a dike as an epoxy squeeze out barrier to those skilled in the art.

As disclosed herein, the dike as an epoxy squeeze out barrier can be used to prevent epoxy or other adhesive from seeping out from between layers of a laminate material in a fuse device. In particular, in some embodiments, the dike can include a non-conductive, photo-imageable material, coating, mask, or the like, such as a polymer with a flammability of zero, that can be formed around a circumference of a cavity. The cavity can house a fuse element, such as a wire and/or a wire-in-air (WIA), in the fuse device, and the dike can prevent the epoxy, in sheet or liquid form, from flowing into the cavity during a final pressing stage of manufacture, including lamination. In some embodiments, the laminate material can include FR4, and central openings and/or internal cut-outs of the laminate material can form the cavity.

Advantageously, because the dike can prevent the epoxy from seeping out from between the layers of the laminate material, known restrike failure and product reliability issues, including element corrosion and nuisance openings, caused by chemical seep can be eliminated and/or minimized as compared to fuse devises known in the art. Additionally, because the dike can control the epoxy from squeezing out into the cavity, the final pressing stage of manufacture during which the laminate material and the epoxy are pressed together can use a higher pressure range than what has been used in connection with fuse devices known in the art, such as, for example an optimized pressure range that can allow for complete sealing of the laminate material and the epoxy in the fuse device. In some embodiments, processing time of the final pressing stage can be even faster than processing times of the final pressing stage of fuse devices known in the art. Still further, a thicker layer of the epoxy can be used than what has been used in connection with fuse devices known in the art, thereby ensuring full encapsulation of all portions of the fuse element between the laminate material.

FIG.2Ais a cross-sectional top view illustrating a fuse device in accordance with disclosed embodiments. As seen inFIG.2A, the fuse device can include at least one layer of a laminate material202, such as FR4, with a cavity206formed by a central opening and/or an internal cut-out of the laminate material202. A fuse element208, such as a wire and/or a WIA, can traverse a diameter of the cavity206so that a central portion of the fuse element208is suspended within the cavity206and ends of the fuse element208are anchored on or by the laminate material202. A dike210can be located on top of, below, and/or in between layers of the laminate material202so that the dike210surrounds a circumference of the cavity206.

FIG.2Bis a cross-sectional side view illustrating the fuse device ofFIG.2Aalong cross-section A, andFIG.2Cis a cross sectional side view illustrating the fuse device ofFIG.2Aalong cross-section B. Epoxy204can be placed on top of, below, and/or in between layers of the laminate material202for bonding thereof. As seen by the arrows inFIG.2BandFIG.2Cdesignating the flow of the epoxy204, the epoxy204can flow away from the cavity206and the dike210when the layers of the laminate material202and the epoxy204are pressed together during manufacture. In particular, in some embodiments, the dike210can prevent the flow of the epoxy204into the cavity206, thereby causing the epoxy204to flow away from the cavity206during manufacture.

With reference toFIG.2C, in particular, ends of the fuse element208and/or at least some of those portions of the element208outside of the cavity and/or not suspended within the cavity206can be located on top of, below, and/or in a slot or a canal of the dike210. In these embodiments, the epoxy204can flow over those ends of the fuse element208outside of the cavity206while the dike210still prevents the epoxy204from flowing into the cavity206.

A dike in accordance with disclosed embodiments can be placed on top of, below, and/or in between any layers of a laminate material of a fuse device where the dike can control or prevent epoxy from squeezing out into a cavity formed by the laminate material. For example, in some embodiments, the dike can be placed between layers of the laminate material where a fuse element is embedded. Additionally or alternatively, in some embodiments, the dike can be placed between layers of the laminate material where the epoxy has a predetermined thickness.

For example,FIG.3Ais an exploded view illustrating a fuse device in accordance with disclosed embodiments. As seen inFIG.3A, the fuse device can include a bottom layer of laminate material302and a bottom middle layer of the laminate material304with epoxy306therebetween for bonding thereof. That is, the epoxy306can bond a top side of the bottom layer of the laminate material302to a bottom side of the bottom middle layer of the laminate material304. The fuse device can also include a top layer of the laminate material308and a top middle layer of the laminate material310with epoxy312therebetween for bonding thereof. That is, the epoxy312can bond a bottom side of the top layer of the laminate material308to a top side of the top middle layer of the laminate material310.

At least the top middle layer of the laminate material310and the bottom middle layer of the laminate material304can include central openings and/or internal cut-outs forming a cavity therein. A fuse element318, such as a wire and/or a WIA, can be placed between the top middle layer of the laminate material310and the bottom middle layer of the laminate material304so that the fuse element318can traverse a diameter of the cavity so that a central portion of the fuse element318is suspended within the cavity and ends of the fuse element318are anchored on or by the top middle layer of the laminate material310and the bottom middle layer of the laminate material304.

A first dike314can be placed on and/or attached to a bottom side of the top middle layer of the laminate material310, and a second dike316can be placed on and/or attached to a top side of the bottom middle layer of the laminate material304. The first dike314can surround a circumference of the cavity formed by the top middle layer of the laminate material310, and the second dike316can surround a circumference of the cavity formed by the bottom middle layer of the laminate material304.

In some embodiments, the first dike314and/or the second dike316can include a photo-imageable material, such as, for example, Vacrel from Dupont, and in some embodiments, the first dike314and/or the second dike316can have an original thickness on an order of 50.8 microns or 2.5 mils. In some embodiments, the top middle layer of the laminate material310and/or the bottom middle layer of the laminate material304can include a glass-reinforced epoxy laminate material, such as FR4.

Epoxy320can be used to bond the bottom side of the top middle layer of the laminate material310, the top side of the bottom middle layer of the laminate material304, the first dike314, the second dike316, and the fuse element318together. When all of these layers are pressed together during a pressing stage of manufacture, such as a press lamination process, the first dike314and the second dike316can prevent the epoxy320from flowing or seeping into the cavity. Also during the pressing stage of manufacture, the original thickness of the first dike314, the second dike316, and the epoxy320can be reduced to a reduced thickness that is some thickness lower than the original thickness.

As a further example,FIG.3Bis an exploded view illustrating a fuse device in accordance with disclosed embodiments. As seen inFIG.3B, the fuse device can include a bottom layer of laminate material322and a bottom middle layer of the laminate material324with epoxy326therebetween for bonding thereof. That is, the epoxy326can bond a top side of the bottom layer of the laminate material322to a bottom side of the bottom middle layer of the laminate material324. The fuse device can also include a top layer of the laminate material328and a top middle layer of the laminate material330with epoxy332therebetween for bonding thereof. That is, the epoxy332can bond a bottom side of the top layer of the laminate material328to a top side of the top middle layer of the laminate material330.

At least the top middle layer of the laminate material330and the bottom middle layer of the laminate material324can include central openings and/or internal cut-outs forming a cavity therein. A fuse element338, such as a wire and/or a WIA, can be placed between the top middle layer of the laminate material330and the bottom middle layer of the laminate material324so that the fuse element338can traverse a diameter of the cavity so that a central portion of the fuse element338is suspended within the cavity and ends of the fuse element338are anchored on or by the top middle layer of the laminate material330and the bottom middle layer of the laminate material324.

A dike334can be placed on, between, and/or attached to a bottom side of the top middle layer of the laminate material330and/or a top side of the bottom middle layer of the laminate material324. When pressed together, the dike334can surround a circumference of the cavity formed by the top middle layer of the laminate material330and/or the bottom middle layer of the laminate material324.

In some embodiments, the dike334can include a film, such as, for example, Dynamask from Eternal, and in some embodiments, the dike334can have an original thickness on an order of 101.6 microns or 4 mils. In some embodiments, the top middle layer of the laminate material330and/or the bottom middle layer of the laminate material324can include a glass-reinforced epoxy laminate material, such as FR4.

Epoxy340can be used to bond the bottom side of the top middle layer of the laminate material330, the top side of the bottom middle layer of the laminate material324, the dike334, and the fuse element338together. When all of these layers are pressed together during a pressing stage of manufacture, such as a press lamination process, the dike334can prevent the epoxy340from flowing or seeping into the cavity. Also during the pressing stage of manufacture, the original thickness of the dike334and the epoxy340can be reduced to a reduced thickness that is some thickness lower than the original thickness.

FIG.4is a cross-sectional top view illustrating a fuse device in accordance with disclosed embodiments. It is to be understood that whileFIG.4identifies sizes, measurements, dimensions, and clearances of various elements, those sizes, measurements, dimensions, and clearances are exemplary only. Indeed, sizes, measurements, dimensions, and clearances of various elements of the fuse device can be varied as would be understood by one of ordinary skill in the art.

As seen inFIG.4, the fuse device can include at least one layer of a laminate material402, such as FR4, with a cavity406formed by a central opening and/or an internal cut-out of the laminate material402. Epoxy404can be placed on top of, below, and/or in between layers of the laminate material402for bonding thereof. A dike410can also be located on top of, below, and/or in between layers of the laminate material402so that the dike410surrounds a circumference of the cavity406. In some embodiments, the fuse device can include a clearance between the epoxy404and the dike410. For example, in some embodiments, this clearance can be on an order of 25.4 microns or 1 mil. Additionally or alternatively, in some embodiments, the fuse device can include a clearance between the cavity406and the dike410. For example, in some embodiments, this clearance can be on an order of 12.7 microns or 0.5 mil. In any embodiment, these clearances relative to the dike410can provide room for spreading of the epoxy404and/or the dike410outside of the cavity406when an original thickness of the epoxy404and/or the dike410is reduced during a pressing stage of manufacture.

In some embodiments, the dike410can include a slot or a canal408patterned or cut out on portions of opposing ends of the dike410. In these embodiments, the canal408can hold a fuse element, such as a wire, and act as a guide for placing the fuse element relative to the laminate material402, the cavity406, and the dike410.

The fuse device as disclosed and described herein can be manufactured in a variety of different manners. For example, when a dike in the fuse device includes a film, the fuse device can be manufactured using a photo-imaging and/or photo-lithography process and method that uses a UV exposure machine and an artwork pattern, an example of which is illustrated inFIG.5.

As seen inFIG.5, a sheet of a photo-imageable film can be placed on top of a middle layer of a sub-assembly and laminated thereon. Then, a sheet of a transparent film with the artwork pattern, such as, for example, a silver halide or a black pattern, can be placed on top of the photo-imageable film. In particular, a background of the artwork pattern can include a non-transparent portion to form a negative image represented by a transparent portion of the artwork pattern.

Once the sheet of the transparent film is placed on top of the sheet of the photo-imageable film, the artwork pattern can be exposed. For example, UV light can bombard the transparent film in the UV exposure machine. The UV light can penetrate the transparent portion of the transparent film to polymerize/cure some portions of the photo-imageable film underneath the transparent film while the UV light can be reflected when hitting the non-transparent portion of the transparent film so that other portions of the photo-imageable film underneath can remain unaffected.

Finally, the sheet of the transparent film can be removed, and developer chemicals can be used to dissolve uncured portions of the photo-imageable film while simultaneously leaving the portions of the photo-imageable film that were cured to create the dike.

Additionally or alternatively, when a dike in the fuse device includes a liquid photo-imageable ink (LPI) that is sprayable, the fuse device can be manufactured using a photo-imaging and/or photo-lithography process and method that uses a UV exposure machine and an artwork pattern, an example of which is illustrated inFIG.6.

As seen inFIG.6, the LPI can be sprayed onto a middle layer of a sub-assembly to achieve a desired deposit thickness. The LPI can be wet, but tack-dried or cured at low temperatures to partially dry in preparation for exposure. Then, a sheet of a transparent film with an artwork pattern, such as, for example, a silver halide or a black pattern, can be placed on top of the LPI. In particular, a background of the artwork pattern can include a non-transparent portion to form a negative image represented by a transparent portion of the artwork pattern.

Once the sheet of the transparent film is placed on top of the LPI, the artwork pattern can be exposed. For example, UV light can bombard the transparent film in the UV exposure machine. The UV light can penetrate the transparent portion of the transparent film to polymerize/cure some portions of the LPI underneath the transparent film while the UV light can be reflected when hitting the non-transparent portion of the transparent film so that other portions of the LPI underneath can remain unaffected.

Finally, the sheet of the transparent film can be removed, and developer chemicals can be used to dissolve uncured portions of the LPI while simultaneously leaving the portions of the LPI that were cured to create the dike.

Additionally or alternatively, when a dike in the fuse device includes a screen print or a stencil of the LPI, the fuse device can be manufactured using a printer and a curing machine, an example of which is illustrated inFIG.7.

As seen inFIG.7, the screen print or the stencil can be placed on top of a middle layer of a sub-assembly. In particular, the screen print or the stencil can include a mask with an aperture that corresponds to a shape intended to be deposited, and a thickness of the screen print or the stencil can correlate to a desired deposit thickness.

Once the screen print or the stencil is placed on top of the middle layer of the sub-assembly, the LPI can be deposited, for example, using a printer that can utilize a squeegee. In particular, the LPI can seep through the aperture of the screen print or the stencil and onto the middle layer of the sub-assembly.

Finally, the screen print or the stencil can be removed, and LPI can be polymerized/cured via heat, for example, from the curing machine, to create the dike.

While the present disclosure makes reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims and equivalents thereof.