ENCAPSULATION TECHNIQUES FOR ELECTRONIC DEVICES BACKGROUND

The present invention relates, in general, to encapsulation techniques.

Universal Serial Bus (USB) drives are most widely used portable storage devices these days. USB drives are expensive as compared to other portable storage devices. Therefore, it is desired that USB drives be protected against mechanical and chemical damage, so that they can operate reliably. Various techniques have been employed to encapsulate and protect various electronic components of USB drives. Most of these techniques are only capable of encapsulating the various electronic components in a non-hermetic seal. This makes such USB drives prone to damage due to presence of water, atmospheric moisture or other chemicals.

In light of the foregoing discussion, there is a need for a storage device that is reliable and is less expensive, compared to conventional USB drives.

SUMMARY

An object of the present invention is to provide an electronic device (and a manufacturing method and system thereof). Another object of the present invention is to provide a storage device that is reliable and is less expensive, compared to conventional storage devices.

Embodiments of the present invention provide a method and system for manufacturing an electronic device. A base substrate with one or more perforations is obtained. The walls of the perforations are coated with an affinitive material having an affinity for a molding material. One or more electronic components are mounted on the base substrate, and are connected in a predefined manner. Subsequently, the molding material is molded over the electronic components, such that the molding material fills in and adheres to the perforations, thereby encapsulating the electronic components.

In an embodiment of the present invention, the perforations may have any desired shape and/or size. For instance, the perforations may have a shape that is curved, polygonal, or a combination thereof. The size of the perforations may, for example, depend on various factors like the size of the base substrate and the location of the perforations on the base substrate. The size of the perforations may also depend on other factors like the number, the size and the location of various components to be mounted on the base substrate.

In an embodiment of the present invention, the perforations are formed at preset locations on the base substrate. For example, the perforations may be located at a periphery of the base substrate.

In an embodiment of the present invention, the molding material includes at least one of: epoxy resin, silicone, acrylic and polyurethane. The affinitive material may, for example, be selected depending on the molding material to be used. In an embodiment of the present invention, the affinitive material includes at least one of: silver, silver alloy, copper, copper alloy, nickel, nickel alloy, palladium, gold, gold alloy, and black oxide.

In one embodiment of the present invention, a Chip-On-Board (COB) type storage device is manufactured by a COB process. Electronic components and connectors of the COB type storage device are encapsulated by a molding material hermetically, as described above. The molding material protects the electronic components and the connectors from mechanical and chemical damage, thereby enhancing the reliability of the storage device. Moreover, the COB type storage device is less expensive compared to conventional storage devices, as bare semiconductor dies are used instead of Integrated Circuits (ICs).

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the claims, wherein like designations denote like elements, and in which:

FIGs. 1A and 1B depict top and front views of a base substrate, in an embodiment of the present invention;

FIGs. 2A and 2B depict top and front views of the base substrate, in an embodiment of the present invention;

FIGs. 3A and 3B depict top and front views of the base substrate, in an embodiment of the present invention;

FIG. 4 depicts a system for manufacturing an electronic device, in an embodiment of the present invention; and FIG. 5 depicts a method of manufacturing an electronic device, in an embodiment of the present invention.

DETAILED DESCRIPTION

Various embodiments of the present invention provide an electronic device and a method and system for manufacturing the electronic device. In accordance with the manufacturing method, a base substrate with one or more perforations Is obtained. The perforations are coated with an affinitive material having an affinity for a molding material. One or more electronic components are mounted on the base substrate, and are connected in a pre-defined manner. Subsequently, the molding material is molded over the electronic components, such that the molding material fills in and adheres to the perforations, thereby encapsulating the electronic components.

Referring now to figures, FIGs. 1A and 1B depict top and front views of a base substrate 102, in an embodiment of the present invention. Base substrate 102 provides mechanical support to various components of an electronic device. Base substrate 102 may, for example, be an electronic substrate that provides electrical connectivity. Examples of base substrate 102 include, but are not limited to. Printed Circuit Boards (PCBs), hybrid microcircuits, and extended PCBs. An extended PCB is a PCB including one or more conductive strips capable of facilitating a Universal Serial Bus (USB) connection.

In an embodiment of the present invention, base substrate 102 includes one or more perforations, shown as a perforation 104a, a perforation 104b, a perforation 104c and a perforation 104d. Perforation 104a, perforation 104b, perforation 104c and perforation 104d are hereinafter referred as perforations 104. As shown in the figure, perforations 104 are in the form of holes through base substrate 102. In an alternative embodiment of the present invention, a perforation may be a cavity formed partially through a surface of a base substrate, such that the perforation does not open at another surface of the base substrate.

In an embodiment of the present invention, the walls of perforations 104 are coated with an affinitive material having an affinity for a molding material. Accordingly, a suitable affinitive material may be selected depending on the molding material to be used. In an embodiment of the present invention, the molding material includes at least one of: epoxy resin, silicone, acrylic and polyurethane. In an embodiment of the present invention, the affinitive material includes at least one of: silver, silver alloy, copper, copper alloy, nickel, nickel alloy, palladium, gold, gold alloy, and black oxide.

In an embodiment of the present invention, perforations 104 are formed at preset locations on base substrate 102. For example, perforations 104 may be located at a periphery of base substrate 102, as shown in FIG. 1A.

In addition, perforations 104 may be formed in any desired shape and/or size. For example, perforations 104 may have a shape that is curved, polygonal, or a combination thereof. With reference to FIG. 1A, perforations 104 are circular A in shape. The size of perforations 104 may depend on various factors like the size of base substrate 102 and the location of perforations 104 on base substrate 102. The size of perforations 104 may also depend on other factors like the number, the size and the location of various components to be mounted on base substrate 102.

FIGs. 2A and 2B depict top and front views of base substrate 102, in an embodiment of the present invention. With reference to FIG. 2A, one or more electronic components, shown as an electronic component 202a and an electronic component 202b, are mounted on preset locations on base substrate 102. Electronic component 202a and electronic component 202b are hereinafter referred as electronic components 202.

Electronic components 202 are connected through connectors in a predefined manner, in an embodiment of the present invention. In an embodiment of the present invention, base substrate 102 includes one or more embedded connectors (not shown) for electrically connecting electronic components 202 in the pre-defined manner. Electronic components 202 may, for example, be thermally bonded to one or more bond pads (not shown) on base substrate 102 using an electrically-conductive paste. In addition, electronic components 202 may be wire bonded to preset bond pads (not shown) on base substrate 102 using wires. The bond pads provide an interface to connect electronic components 202 to the embedded connectors.

FIGs. 3A and SB depict top and front views of base substrate 102, in an embodiment of the present invention. With reference to FIGs. 3A and 3B, a molding material 302 is molded over electronic components 202. Consequently, molding material 302 fills in and adheres to perforations 104, and encapsulates electronic components 202 and the connectors.

As mentioned above, the affinitive material has an affinity for molding material 302. Therefore, the affinitive material, coated on the walls of perforations 104, enhances the adhesion of molding material 302 to base substrate 102. Consequently, molding material 302 encapsulates electronic components 202 and the connectors hermetically.

FIGs. 1A-1B, 2A-2B and 3A-3B depict various stages in which an electronic device is manufactured, in an embodiment of the present invention. In an embodiment of the present invention, the electronic device is a Surface Mount Technology (SMT) type device manufactured by an SMT process. An SMT process includes mounting an Integrated Circuit (IC) on an electronic substrate. Consider, for example, that the electronic device is a storage device. In such a case, at least one of electronic components 202 may be a Flash IC capable of storing data.

In accordance with another embodiment of the present invention, the electronic device is a Chip-On-Board (COB) type device manufactured by a COB process. A COB process includes directly mounting a bare semiconductor die on an electronic substrate, and electrically connecting the bare semiconductor die to appropriate bond pads on the electronic substrate.

It is to be understood that the specific designation for the electronic device so manufactured and its various components is for the convenience of the reader and is not to be construed as limiting the electronic device to a specific size, shape, type, or arrangement of its components.

FIGs. 1A-1B, 2A-2B and 3A-3B are merely an example, which should not unduly limit the scope of the claims herein. For instance, molding material 302 may be molded over more than one surface of base substrate 102.

FIG. 4 depicts a system 400 for manufacturing an electronic device, in an embodiment of the present invention. System 400 includes a base-obtaining unit 402 that includes a perforation-forming unit 404 and a coating unit 406, a component-mounting unit 408, a connecting unit 410, and a molding unit 412.

Base-obtaining unit 402 is adapted to obtain a base substrate. The base substrate includes one or more embedded connectors for electrically connecting electronic components mounted on the base substrate in a pre-defined manner, in an embodiment of the present invention.

Perforation-forming unit 404 is adapted to form one or more perforations on the base substrate. In an embodiment of the present invention, perforation- forming unit 404 includes a drill adapted to mechanically drill the perforations through the base substrate. In an alternative embodiment of the present invention, the perforations may be drilled partially through a surface of the base substrate, such that the perforations do not open at another surface of the base substrate. Perforation-forming unit 404 may be automated and controlled by a drill file that describes the location, size and/or shape of each perforation.

Alternatively, perforation-forming unit 404 may include other suitable cutting tools.

In another embodiment of the present invention, perforation-forming unit 404 is implemented in the form of an injection molding machine adapted to mold a base substrate of a desired shape and size along with perforations at desired locations and of desired shape and size. Accordingly, the perforations may be formed using suitable molds during molding of the base substrate.

Coating unit 406 is adapted to coat the walls of the perforations with an affinitive material having an affinity for a molding material. Coating unit 406 may, for example, be adapted to choose a suitable affinitive material depending on the molding material to be used. In an embodiment of the present invention, the molding material includes at least one of: epoxy resin, silicone, acrylic and polyurethane. In an embodiment of the present invention, the affinitive material includes at least one of: silver, silver alloy, copper, copper alloy, nickel, nickel alloy, palladium, gold, gold alloy, and black oxide.

In an embodiment of the present invention, the walls of the perforations are plated with the affinitive material. In a specific embodiment of the present invention, the perforations are etched using, for example, plasma-etching before the perforations are plated.

In addition, coating unit 406 may be adapted to control the thickness of the coat of the affinitive material. For example, the thickness of the coat may range from 20 mil to 60 mil.

Component-mounting unit 408 is adapted to mount one or more electronic components on preset slots on the base substrate. At least one of these electronic components is capable of storing data, in an embodiment of the present invention. Component-mounting unit 408 may, for example, be a pick- and-place unit that is programmed to pick electronic components and place them on appropriate slots on a base substrate.

Connecting unit 410 is adapted to electrically connect the electronic components in a pre-defined manner through one or more connectors.

Molding unit 412 is adapted to mold the molding material over the electronic components, such that the molding material fills in and adheres to the perforations. Consequently, the molding material encapsulates the electronic components and the connectors hermetically.

Molding unit 412 may, for example, be a transfer molding machine adapted to mold the molding material over a surface of the base substrate on which the electronic components are mounted. In an alternative embodiment of the present invention, the molding material is molded over more than one surface of the base substrate.

In an embodiment of the present invention, the base substrate is capable of sustaining compressive forces applied during molding. Accordingly, the base
substrate may, for example, be made of a material with specific physical properties. Some of these physical properties may depend on the physical dimensions of the base substrate.

Accordingly, a base substrate of specific dimensions may be used for manufacturing the electronic device. In one example, the base substrate is a PCB. In such a case, the thickness of the PCB may, for example, range from 0.2 mm to 0.8 mm.

FIG. 4 is merely an example, which should not unduly limit the scope of the claims herein. For instance, the electronic device so manufactured may be cased in a casing, in order to protect the electronic device from external factors, such as heat, moisture and scratches. The casing may be attached to the base substrate and/or the molded molding material, for example, through a gluing process or an ultrasonic welding process.

FIG. 5 depicts a method of manufacturing an electronic device, in an embodiment of the present invention. At step 502, a base substrate is obtained. The base substrate includes one or more embedded connectors for electrically connecting electronic components mounted on the base substrate in a pre-defined manner, in an embodiment of the present invention. Step 502 includes step 504 and step 506.

In accordance with step 504, one or more perforations are formed on the base substrate.

In an embodiment of the present invention, step 504 is performed by a drill adapted to mechanically drill the perforations through the base substrate. In an alternative embodiment of the present invention, the perforations may be drilled partially through a surface of the base substrate, such that the perforations do not open at another surface of the base substrate. In addition, the drill may be automated and controlled by a drill file that describes the location, size and/or shape of each perforation. Alternatively, step 504 may be performed by other suitable cutting tools.

In another embodiment of the present invention, step 504 may be performed by an injection molding machine adapted to mold a base substrate of a desired shape and size along with perforations at desired locations and of desired shape and size. Accordingly, the perforations may be fumed using suitable molds during molding of the base substrate.

In accordance with step 506, the walls of the perforations are coated with an affinitive material having an affinity for a molding material. Therefore, a suitable affinitive material may be selected depending on the molding material to be used. In an embodiment of the present invention, the molding material includes at least one of: epoxy resin, silicone, acrylic and polyurethane. In an embodiment of the present invention, the affinitive material includes at least one of: silver, silver alloy, copper, copper alloy, nickel, nickel alloy, palladium, gold, gold alloy, and black oxide.

In an embodiment of the present invention, step 506 includes plating the walls of the perforations with the affinitive material. In a specific embodiment of the present invention, an optional step of etching the perforations may be performed before step 506.

The optional step may, for example, be performed using plasma-etching.

In addition, step 506 may include a sub-step of controlling the thickness of the coat of the affinitive material. For example, the thickness of the coat may range from 20 mil to 60 mil.

An exemplary base substrate so obtained may, for example, appear like base substrate 102 shown in FIGs. 1A and IB.

At step 508, one or more electronic components are mounted on preset slots on the base substrate. At least one of these electronic components is capable of storing data, in an embodiment of the present invention.

step 508 may, for example, be performed by a pick-and-place unit that is programmed to pick electronic components and place them on appropriate slots on a base substrate.
Continuing from the above example, exemplary electronic components may be mounted on the base substrate, as shown in FIGs. 2A and 2B.

At step 510, the electronic components are electrically connected in a pre-defined manner through one or more connectors.

Subsequently, at step 512, the molding material is molded over the electronic components, such that the molding material fills in and adheres to the perforations. Consequently, the molding material encapsulates the electronic components and the connectors hermetically.

Continuing from the above example, an exemplary molding material may be molded over the electronic components, as shown in FIGs. 3A and SB.

Step 512 may, for example, be performed by a transfer molding machine adapted to mold the molding material over a surface of the base substrate on which the electronic components are mounted. In an alternative embodiment of the present invention, the molding material is molded over more than one surface of the base substrate.

In an embodiment of the present invention, the base substrate is capable of sustaining compressive forces applied during molding at step 512. Accordingly, the base substrate may, for example, be made of a material with specific physical properties. Some of these physical properties may depend on the physical dimensions of the base substrate.

Accordingly, a base substrate of specific dimensions may be used for manufacturing the electronic device. In one example, the base substrate is a PCB. In such a case, the thickness of the PCB may, for example, range from 0.2 mm to 0.8 mm.

It should be noted here that steps 502-512 are only illustrative and other alternatives can also be provided where steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

In an embodiment of the present invention, steps 502-512 may be performed on a panel including a plurality of base substrates. In such a case, an additional step of de-panelizing individual base substrates may be pardoned after step 512. The step of de-panelizing may, for example, be performed by a laser-cutting device.

Finally, the electronic device so manufactured may be cased in a casing, in order to protect the electronic device from external factors, such as heat, moisture and scratches.

The casing may be attached to the base substrate and/or the molded molding material, for example, through a gluing process or an ultrasonic welding process.

Embodiments of the present invention provide a method and system for manufacturing an electronic device. In an embodiment of the present invention, the method may be suitably used in the manufacturing of storage devices, where electronic components mounted on an electronic substrate are encapsulated by a molding material hemnetically. The molding material protects the electronic components from mechanical and chemical damage, thereby enhancing the reliability of the storage device.

In one embodiment of the present invention, a COB type storage device is manufactured by a COB process. As the COB process requires less space, the size of the COB type storage device reduces. In addition, the storage capacity of the COB type storage device may be increased without changing the overall dimensions of its casing. Moreover, the cost of manufacture is reduced, as bare semiconductor dies are used.

In the description herein for the embodiments of the present invention, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of the embodiments of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the present invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of the embodiments of the present invention.

Reference throughout this specification to "one embodiment", "an embodiment", or "a specific embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of an embodiment of the present invention and not necessarily in all embodiments. Thus, respective appearances of the phrases "in one embodiment", "in an embodiment", or "in a specific embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present invention may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the present invention.

It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.

As used in the description herein and throughout the claims that follow, "a", "an", and "the" includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the present invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the present invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.

Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of the embodiments of the present invention will be employed without a corresponding use of other features without departing from the scope and spirit of the present invention as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit pf the present invention. It is intended that the present invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this present invention, but that the present invention will include any and all embodiments and equivalents falling within the scope of the appended claims.

CLAIMS

WHAT IS CLAIMED IS:

1. An electronic device comprising:

a base substrate for providing support, the base substrate comprising one or more perforations;

one or more electronic components mounted on the base substrate; one or more connectors for electrically connecting the electronic components In a pre-defined manner; and

a molding material molded over the electronic components, such that the molding material fills in and adheres to the perforations on the base substrate, wherein the molding material encapsulates the electronic components and the connectors.

2. The electronic device of claim 1 is a storage device, wherein at least one electronic component is capable of storing data.

3. The electronic device of claim 1, wherein the walls of the perforations are coated with an affinitive material having an affinity for the molding material, the affinitive material enhancing the adhesion of the molding material to the perforations.

4. The electronic device of claim 3, wherein the affinitive material is selected from the group consisting of silver, silver alloy, copper, copper alloy, nickel, nickel alloy, palladium, gold, gold alloy, and black oxide.

5. The electronic device of claim 1, wherein the shape of the perforations is either curved or polygonal.

6. The electronic device of claim 1, wherein the perforations are located at a periphery of the base substrate.

7. The electronic device of claim 1, wherein the base substrate comprises an extended Printed Circuit Board (PCB), the extended RGB comprising one or more conductive strips capable of facilitating a Universal Serial Bus (USB) connection.

8. The electronic device of claim 1 is a Chip-On-Board (COB) type device.

9. The electronic device of claim 1 is a Surface Mount Technology (SMT) type device.

10. An electronic device substantially as herein above described in the specification with reference to the accompanying drawings.