Banks as epoxy resin extrusion barriers in fuse devices

Abstract

A bank as an epoxy extrusion barrier in a fuse apparatus is provided. The fuse apparatus may include a first layer of laminate and a second layer of laminate, a cavity formed by central openings of the first layer of laminate and the second layer of laminate, a fuse element supported by at least one of the first layer of laminate and the second layer of laminate and traversing the cavity, an adhesive positioned on the first layer of laminate and the second layer of laminate for adhesion thereof, and a bank positioned on at least one of the first layer of laminate and the second layer of laminate and surrounding a periphery of the cavity. The bank may prevent epoxy resin from flowing into the cavity when the first and second layers of laminate, the fuse element, the adhesive, and the bank are pressed together during fabrication.

Description

Technical Field

[0001] The present disclosure relates generally to fuse devices. More particularly, the present disclosure relates to a dike as a barrier to epoxy extrusion in a fuse device. Background Art

[0002] Many fuse devices use epoxy or other adhesives to bond their layers. However, when the layers of the fuse device and the epoxy are pressed together during manufacturing, the epoxy may squeeze out from between the layers, which may cause operational problems. For example, as shown in FIG. 1 , in a fuse device including a laminate 102 (such as FR4) having a cavity 106 for a fuse element (such as a wire-in-air (WIA)), epoxy 104 may be placed on top of, below, and / or between the layers of the laminate 102 for bonding thereof. However, when the layers of the laminate 102 and epoxy 104 are pressed together during manufacturing, the epoxy 104 may squeeze out from between the layers of the laminate 102 and into the cavity 106, as shown by the arrows in FIG. 1 representing the flow of the epoxy 104.

[0003] This extrusion may cause re-breakdown failures and / or product reliability issues during short circuit events. In fact, when epoxy resin 104 penetrates into cavity 106, epoxy resin will contact with fuse element, resulting in corrosion of element. In addition, when epoxy resin 104 penetrates into cavity 106, the effective volume for fuse element in cavity 106 will be reduced, resulting in interference (nuisance) opening. At any time when epoxy resin 104 penetrates into cavity 106, energy loss leading to overload failure may occur due to the fuse element not meeting the required disconnection time standard, and / or current overload or short circuit failure may occur due to fuse burning. In this regard, the heat from the current overload or short circuit event used to melt the fuse element and realize (enact) the fuse function may be lost by dissipation or by changing the ideal conditions (such as, for example, the effective volume of cavity 106) that promote or facilitate enhanced function.

[0004] In view of the foregoing, there is a continuing need for apparatus and methods for preventing epoxy extrusion in fuse devices. Summary of the invention

[0005] This brief summary is provided to introduce a selection of concepts in a simplified form that are further described in the detailed description below. This brief summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to assist in determining the scope of the claimed subject matter.

[0006] In some embodiments, a device according to the present disclosure may include a first layer of laminated material, a second layer of laminated material, a cavity formed by a central opening of the first layer of laminated material and the second layer of laminated material, a fuse element supported by at least one of the first layer of laminated material and the second layer of laminated material and crossing the cavity, an adhesive located on at least one of the first layer of laminated material and the second layer of laminated material for bonding thereof, and a dam located on at least one of the first layer of laminated material and the second layer of laminated material and surrounding the periphery of the cavity. When the first layer of laminated material, the second layer of laminated material, the fuse element, the adhesive, and the dam are pressed together during manufacturing, the dam can prevent epoxy resin from flowing into the cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a cross-sectional side view showing a fuse device known in the art.

[0008] Figure 2A is a cross-sectional top view showing a fuse device according to a disclosed embodiment.

[0009] Figure 2B is a diagram showing a method according to the disclosed embodiment Figure 2A A cross-sectional side view of a fuse device of section A.

[0010] Figure 2C is a diagram showing a method according to the disclosed embodiment Figure 2A Section B is a cross-sectional side view of a fuse device.

[0011] Figure 3A is an exploded view showing a fuse device according to the disclosed embodiment.

[0012] Figure 3B is an exploded view showing a fuse device according to the disclosed embodiment.

[0013] Figure 4 is a cross-sectional top view showing a fuse device according to a disclosed embodiment.

[0014] Figure 5 is a flow chart illustrating a method according to the disclosed embodiments.

[0015] Figure 6 is a flow chart illustrating a method according to the disclosed embodiments.

[0016] Figure 7 is a flow chart illustrating a method according to the disclosed embodiments. DETAILED DESCRIPTION

[0017] Exemplary embodiments of a dam as an epoxy extrusion barrier according to the present disclosure will now be described more fully below with reference to the accompanying drawings. However, the dam as an epoxy extrusion barrier can be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that the present disclosure conveys certain exemplary aspects of the dam as an epoxy extrusion barrier to those skilled in the art.

[0018] As disclosed herein, a dam as an epoxy extrusion barrier can be used to prevent epoxy or other adhesives from seeping out from between layers of a laminate in a fuse device. In particular, in some embodiments, the dam can include a non-conductive, photo-imageable material, coating, mask, or the like, such as a zero flammability polymer, which can be formed at the periphery of a cavity. The cavity can accommodate a fuse element, such as a wire and / or a flying wire (WIA), in a fuse device, and the dam can prevent epoxy in sheet or liquid form from flowing into the cavity during the final pressing stage of manufacturing (including lamination). In some embodiments, the laminate can include FR4, and a central opening and / or an internal cutout of the laminate can form the cavity.

[0019] Advantageously, because the dam can prevent epoxy from seeping out from between the layers of the laminate, known restriking failures and product reliability issues caused by chemical seepage, including component corrosion and interference openings, can be eliminated and / or minimized compared to fuse devices known in the art. In addition, because the dam can control the extrusion of epoxy into the cavity, the final pressing stage of manufacturing (during which the laminate and epoxy are pressed together) can use a higher pressure range than the pressure range known in the art for use in conjunction with fuse devices, such as, for example, an optimal pressure range that can allow for complete sealing of the laminate and epoxy in the fuse device. In some embodiments, the processing time of the final pressing stage can be even faster than the processing time of the final pressing stage of fuse devices known in the art. In addition, a thicker epoxy layer can be used than the epoxy layer known in the art for use in conjunction with fuse devices, thereby ensuring that all portions of the fuse element are completely encapsulated between the laminate.

[0020] Figure 2A is a cross-sectional top view showing a fuse device according to the disclosed embodiment. Figure 2AAs shown, the fuse device may include at least one layer of laminate material 202, such as FR4, having a cavity 206 formed by a central opening and / or internal cutouts of the laminate material 202. A fuse element 208, such as a wire and / or WIA, may traverse the diameter of the cavity 206, such that a central portion of the fuse element 208 is suspended within 206, and ends of the fuse element 208 are anchored on or by the laminate material 202. A dam 210 may be positioned on top of, below, and / or between layers of the laminate material 202, such that the dam 210 surrounds the perimeter of the cavity 206.

[0021] Figure 2B It is shown Figure 2A A cross-sectional side view of the fuse device along section A, and Figure 2C It shows Figure 2A 2 is a cross-sectional side view of a fuse device along section B. Epoxy resin 204 may be placed on top of, below, and / or between layers of laminate material 202 for bonding thereof. Figure 2B and Figure 2C As shown by the arrows indicating the flow of epoxy 204 in FIG. 2 , when the layers of laminate 202 and epoxy 204 are pressed together during manufacturing, epoxy 204 can flow away from cavity 206 and dam 210. In particular, in some embodiments, dam 210 can prevent epoxy 204 from flowing into cavity 206, thereby causing epoxy 204 to flow away from cavity 206 during manufacturing.

[0022] Reference Figure 2C In particular, at least some of the ends of the fuse element 208 and / or those portions of the element 208 that are outside the cavity and / or not suspended within the cavity 206 can be located on top of, below, and / or in the grooves or channels of the dam 210. In these embodiments, the epoxy 204 can flow over those ends of the fuse element 208 that are outside the cavity 206, while the dam 210 still prevents the epoxy 204 from flowing into the cavity 206.

[0023] A dam according to the disclosed embodiments may be placed on top of, below, and / or between any layers of a laminate material of a fuse device, wherein the dam may control or prevent epoxy from squeezing out into a cavity formed by the laminate material. For example, in some embodiments, the dam may be placed between layers of a laminate material in which a fuse element is embedded. Additionally or alternatively, in some embodiments, the dam may be placed between layers of a laminate material wherein the epoxy has a predetermined thickness.

[0024] For example, Figure 3A is an exploded view showing a fuse device according to the disclosed embodiment. Figure 3AAs shown, the fuse device may include a bottom layer of laminate material 302 and a bottom middle layer of laminate material 304, with epoxy resin 306 therebetween for bonding. That is, epoxy resin 306 may bond the top side of the bottom layer of laminate material 302 to the bottom side of the bottom middle layer of laminate material 304. The fuse device may also include a top layer of laminate material 308 and a top middle layer of laminate material 310, with epoxy resin 312 therebetween for bonding. That is, epoxy resin 312 may bond the bottom side of the top layer of laminate material 308 to the top side of the top middle layer of laminate material 310.

[0025] At least the top middle layer of laminate material 310 and the bottom middle layer of laminate material 304 may include a central opening and / or internal cutouts forming a cavity therein. A fuse element 318 (such as a wire and / or WIA) may be placed between the top middle layer of laminate material 310 and the bottom middle layer of laminate material 304 such that fuse element 318 may traverse the diameter of the cavity, such that a central portion of fuse element 318 is suspended within the cavity and ends of fuse element 318 are anchored on or by the top middle portion of laminate material 310 and the bottom middle portion of laminate material 304.

[0026] The first bank 314 may be placed and / or attached to the bottom side of the top intermediate layer of the laminate material 310, and the second bank 316 may be placed and / or attached to the top side of the bottom intermediate layer of the laminate material 304. The first bank 314 may surround the perimeter of the cavity formed by the top intermediate layer of the laminate material 310, and the second bank 316 may surround the perimeter of the cavity formed by the bottom intermediate layer of the laminate material 304.

[0027] In some embodiments, first bank 314 and / or second bank 316 may include a photoimageable material, such as, for example, Vacrel from DuPont, and in some embodiments, first bank 314 and / or second bank 316 may have an original thickness of about 50.8 microns or 2.5 mils. In some embodiments, the top intermediate layer of laminate 310 and / or the bottom intermediate layer of laminate 304 may include a glass reinforced epoxy laminate, such as FR4.

[0028] Epoxy 320 may be used to bond together the bottom side of the top middle layer of laminate 310, the top side of the bottom middle layer of laminate 304, first dam 314, second dam 316, and fuse element 318. When all of these layers are pressed together during a press-fit stage of manufacturing, such as a press-fit lamination process, first dam 314 and second dam 316 may prevent epoxy 320 from flowing or seeping into the cavity. Also during the press-fit stage of manufacturing, the original thickness of first dam 314, second dam 316, and epoxy 320 may be reduced to a reduced thickness that is lower than the original thickness.

[0029] As another example, Figure 3B is an exploded view showing a fuse device according to the disclosed embodiment. Figure 3B As shown, the fuse device may include a bottom layer of laminate 322 and a bottom middle layer of laminate 324, with epoxy 326 therebetween for bonding. That is, epoxy 326 may bond the top side of the bottom layer of laminate 322 to the bottom side of the bottom middle layer of laminate 324. The fuse device may also include a top layer of laminate 328 and a top middle layer of laminate 330, with epoxy 332 therebetween for bonding. That is, epoxy 332 may bond the bottom side of the top layer of laminate 328 to the top side of the top middle layer of laminate 330.

[0030] At least the top middle layer of laminate material 330 and the bottom middle layer of laminate material 324 may include a central opening and / or internal cutouts forming a cavity therein. A fuse element 338 (such as a wire and / or WIA) may be placed between the top middle layer of laminate material 330 and the bottom middle layer of laminate material 324 such that fuse element 338 may traverse the diameter of the cavity, such that a central portion of fuse element 338 is suspended within the cavity and ends of fuse element 338 are anchored on or by the top middle portion of laminate material 330 and the bottom middle portion of laminate material 324.

[0031] The dam 334 may be placed on, between, and / or attached to the bottom side of the top intermediate layer of the laminate 330 and / or the top side of the bottom intermediate layer of the laminate 324. The dam 334 may surround the perimeter of the cavity formed by the top intermediate layer of the laminate 330 and / or the bottom intermediate layer of the laminate 324 when pressed together.

[0032] In some embodiments, bank 334 may include a film such as, for example, Dynamask from Eternal, and in some embodiments, bank 334 may have an original thickness of about 101.6 microns or 4 mils. In some embodiments, the top intermediate layer of laminate 330 and / or the bottom intermediate layer of laminate 324 may include a glass reinforced epoxy laminate such as FR4.

[0033] Epoxy 340 may be used to bond together the bottom side of the top intermediate layer of laminate 330, the top side of the bottom intermediate layer of laminate 324, dam 334, and fuse element 338. When all of these layers are pressed together during a press-fit stage of manufacturing, such as a press-fit lamination process, dam 334 may prevent epoxy 340 from flowing or seeping into the cavity. Also during the press-fit stage of manufacturing, the original thickness of dam 334 and epoxy 340 may be reduced to a reduced thickness that is lower than the original thickness.

[0034] Figure 4 is a cross-sectional top view showing a fuse device according to the disclosed embodiment. It should be understood that although Figure 4 The sizes, measurements, dimensions and spacings of various components are identified, but these sizes, measurements, dimensions and spacings are exemplary only. In fact, as those skilled in the art will appreciate, the sizes, measurements, dimensions and spacings of various components of the fuse device may vary.

[0035] like Figure 4 As shown, the fuse device may include at least one layer of laminate material 402, such as FR4, having a cavity 406 formed by a central opening and / or internal cutouts of the laminate material 402. Epoxy 404 may be placed on top of, below, and / or between the layers of the laminate material 402 for bonding. A dam 410 may also be positioned on top of, below, and / or between the layers of the laminate material 402 so that the dam 410 surrounds the periphery of the cavity 406. In some embodiments, the fuse device may include a gap between the epoxy 404 and the dam 410. For example, in some embodiments, the gap may be about 25.4 microns or 1 mil. Additionally or alternatively, in some embodiments, the fuse device may include a gap between the cavity 406 and the dam 410. For example, in some embodiments, the gap may be about 12.7 microns or 0.5 mil. In any embodiments, these gaps relative to the dam 410 may provide space for the epoxy 404 and / or dam 410 to diffuse outside of the cavity 406 when the original thickness of the epoxy 404 and / or dam 410 is reduced during the lamination stage of manufacturing.

[0036] In some embodiments, the dam 410 may include grooves or channels 408 patterned or cut on portions of opposing ends of the dam 410. In these embodiments, the channels 408 may accommodate a fuse element, such as a wire, and serve as a guide for positioning the fuse element relative to the laminate 402, the cavity 406, and the dam 410.

[0037] The fuse devices disclosed and described herein can be manufactured in a variety of different ways. For example, when the bank in the fuse device comprises a film, the fuse device can be manufactured using a photo-imaging and / or photolithography process and method using a UV machine and an artwork pattern, examples of which are as follows: Figure 5 shown.

[0038] Additionally or alternatively, when the banks in the fuse device include a sprayable liquid photoimageable ink (LPI), the fuse device can be manufactured using photoimaging and / or photolithography processes and methods using a UV machine and an artwork pattern, examples of which are as follows: Figure 6 shown.

[0039] Additionally or alternatively, when the bank in the fuse device comprises a screen print or stencil of the LPI, the fuse device can be manufactured using a printer and a curing machine, an example of which is Figure 7 shown.

[0040] As used herein, an element or step cited in the singular and beginning with the word "a" or "an" should be understood as not excluding multiple elements or steps, unless such exclusion is explicitly cited. In addition, reference to "one embodiment" of the present disclosure should not be interpreted as excluding the existence of additional embodiments that also include the described features.

[0041] Although the present disclosure has been described with reference to certain embodiments, many modifications, variations and changes to the described embodiments are possible without departing from the field and scope of the present disclosure as defined in the appended claims. Therefore, the present disclosure is not limited to the described embodiments, but has a full scope defined by the language of the following claims and their equivalents.

Claims

1. A device, comprising: a first layer of laminated material; a second layer of laminate material; a cavity formed by a central opening of the first layer of laminate material and the second layer of laminate material; a fuse element supported by at least one of the first layer of laminate material and the second layer of laminate material and traversing the cavity; an adhesive positioned on at least one of the first layer of laminated material and the second layer of laminated material for bonding thereof; and a dam positioned on at least one of the first layer of laminate material and the second layer of laminate material and surrounding a periphery of the cavity, Wherein, when the first layer of laminate material, the second layer of laminate material, the fuse element, the adhesive, and the dam are pressed together during manufacturing, the dam prevents epoxy resin from flowing into the cavity.

Images