Patent Description:
Light is getting more and more interesting in the field of data processing. By transferring the data by light, losses (e.g., through wire attenuation) can be reduced. To use light for data transfer, electrical signals are translated into light signals and are inserted into an optical fiber (or fiber optics). On the receiver side, the light is transferred back into electrical signals. On both sides of the optical fiber, the fiber has to be fixed to a chip or package to achieve both mechanical coupling for stability and optical coupling to receive optical signals from the electrical circuitry and emit optical signals to the electrical circuitry.

<CIT> relates to an optoelectronic conversion header, which includes a mounting substrate, a wiring substrate on the mounting substrate, and an integrated circuit on the wiring substrate. The mounting substrate may serve as a heat sink. The optoelectronic conversion header also includes a light emitter and an optical fiber inserted into a ferrule. The light emitter and the ferrule are shown to be located on the mounting substrate. A light absorbing resin covers the entire optoelectronic conversion header.

<CIT> relates to a photoelectric conversion device. The device includes an electrical wiring formed on a circuit board. The device includes an optical fiber, and a molded portion covering an end portion and an end face of the optical fiber. The device further includes an optical device optically coupled to the optical fiber through the molded portion.

<CIT> discloses an optical transmission module including a substrate having a substantially trapezoidal first groove, an optical device mounted on the substrate for performing conversion between light and electricity, and a ferrule having a center hole and received in the first groove so as to be supported by beveled wall surfaces defining the first groove. An optical fiber is inserted and fixed in the center hole of the ferrule. The ferrule is cut away at a portion opposed to a bottom surface of the first groove.

<CIT> discloses an optic communications device including an optic communications module which includes a base, an optical element, a fiber optic piece, a ferrule, a transparent resin film, a wiring film, and a sealing member. The base plate and some other elements are divided into individual pieces each making up the optic communications module.

<CIT> discloses an optical coupler including a semiconductor optical device, a lead frame on which the semiconductor optical device is disposed, a glass submount exemplifying a submount having light transmission and a lens provided on the glass submount. Further, a processing circuit covered with a molding portion is part of the optical coupler. The glass submount is bonded to the lead frame in such a way that the optical portion of the semiconductor optical device which is electrically connected to the glass submount faces an aperture.

This disclosure describes a chip package that facilitates a self-aligning optical and mechanical edge connection to an optical fiber. The chip package described herein facilitates the connection of optical fibers directly with the chip package. The chip package described herein allows for shorter connection lengths and reduces the footprint of the system. Additionally, the integration ratio can be increased.

The chip package formation process can include the following features:.

Other features are readily apparent by the following disclosure, accompanying figures, and the claims.

<FIG> is a schematic block diagram of an example optical fiber accommodating chip package <NUM> in accordance with embodiments of the present disclosure. Chip package <NUM> includes a chip <NUM> adjacent to and electrically coupled to an optical transducer <NUM>. Optical transducer <NUM> can receive electrical signals from the chip <NUM> and convert the electrical signals into optical signals. The optical transducer <NUM> can emit the optical signals through the optical element <NUM>. Optical element <NUM> can include any type of fiber optic compatible material (e.g., can transmit optical signals to and from an optical fiber), such as glass, optical-grade polymer, or other material. The chip package <NUM> includes a base <NUM> upon which the chip <NUM>, the optical transducer <NUM>, and the optical element <NUM> reside. The base <NUM> can include a dielectric material that can be processed to include a redistribution layer (RDL) <NUM>. The RDL <NUM> can provide electrical interconnectivity between integrated circuit elements, and can facilitate access to integrated circuit elements through contact points, such as solder balls <NUM>, contact pads, or other electrical contacts.

The chip package <NUM> also includes an encasement <NUM>. Encasement <NUM> can include a mold compound, such as that used in embedded Wafer Level Ball Grid Array (eWLB) processing or other fan-out WLB processing techniques and flip-chip, or any other process that uses a mold cap. (EG filled epoxy-based materials) The mold compound used during formation of the encasement <NUM> can be a solid molding compound or a liquid molding compound. Examples of a mold compound include an EG-filled epoxy-based material.

The encasement <NUM> includes a notch <NUM>. The notch <NUM> can be formed on the top surface of the encasement <NUM> at a location proximate the optical transducer <NUM>. For example, the notch <NUM> can be formed on the top surface of the encasement <NUM> above the optical transducer <NUM> and near the edge of the chip package <NUM>. The notch <NUM> can be formed via mold pressing. The notch <NUM> can have a predetermined shape and size, and can be positioned to facilitate self-alignment of the optical connector component (shown in <FIG>). For example, the notch <NUM> can be formed based on the shape and size of the corresponding optical fiber connector.

The optical element <NUM> resides proximate the edge of the chip package <NUM>. The optical element <NUM> held in place by the encasement <NUM> or sandwiched between the encasement <NUM> and the base <NUM>. A side of the optical element is flush (or substantially flush) with the edge of the chip package <NUM> and is, according to the invention, flush with the edge of the encasement <NUM>. The side of the optical element <NUM> that is flush with the edge of the chip package <NUM> is exposed at the edge of the chip package <NUM> to transmit (i.e., optically transmit) optical signals to and from an optical fiber.

<FIG> is a schematic block diagram of another example optical fiber accommodating chip package <NUM> in accordance with embodiments of the present disclosure. Chip package <NUM> is similar to that of chip package <NUM> and includes similar features as shown in <FIG>. Chip package <NUM>, however, includes a cut <NUM> instead of a notch. Cut <NUM> can be formed by a saw or other cutting device. In some embodiments, the cut <NUM> can traverse along the entire chip package <NUM>. In some embodiments, the cut <NUM> can be formed without cutting through the entire encasement <NUM>, but rather, can be formed at a discrete location above the optical transducer <NUM> and/or above the optical element <NUM>, depending on the shape and size of the optical fiber connector. The cut <NUM> can be formed at a top side of the encasement <NUM> proximate the optical transducer <NUM>. The shape of the cut <NUM> can be predetermined to accommodate the optical fiber connector, shown in <FIG>.

<FIG> is a schematic block diagram of an example optical fiber accommodating chip package and an example optical fiber connector in accordance with embodiments of the present disclosure. In <FIG>, an optical fiber connector <NUM> is attached to the chip package <NUM>. The optical fiber connector <NUM> is shaped to contact the top of the encasement <NUM> and the bottom of the chip package <NUM> (e.g., by contacting the base <NUM>). The optical fiber connector <NUM> can also be physically biased to form a clamp to apply a clamping force on the chip package <NUM>.

The optical fiber connector <NUM> can include a fiber guide <NUM>. Fiber guide <NUM> can be configured to receive an optical fiber <NUM>. The fiber guide <NUM> can provide structure support and strain relief for the optical fiber <NUM>. The fiber guide <NUM> can hold the optical fiber <NUM> in place, and when the optical fiber connector <NUM> is connected to the chip package <NUM>, the fiber guide <NUM> can hold the optical fiber <NUM> in place and in contact with the optical element <NUM>, so that optical signals can be transmitted from the optical fiber <NUM> to the optical element <NUM>, and optical signals can be transmitted from the optical element <NUM> to the optical fiber <NUM>.

In some embodiments, a glue <NUM> can be used to add further structural support to the connection between the optical fiber connector <NUM> and the chip package <NUM>. The glue <NUM> can be an optically transparent glue. The glue <NUM> can bind the optical fiber connector <NUM> to the encasement <NUM> and other parts of the chip package <NUM> as needed.

In some embodiments, the optical fiber connector <NUM> includes a connector hook <NUM>. Connector hook <NUM> can fit into a notch / cut <NUM>. In <FIG>, the notch / cut <NUM> represents either the notch <NUM> from <FIG> or the cut <NUM> from <FIG>. Either the notch or the cut can be used, depending on the design of the connector hook <NUM>. In some embodiments, no notch or cut is used, and the optical fiber connector <NUM> can clamp onto the chip package <NUM>. The connector hook <NUM> can be structured to match the notch / cut <NUM>. Or, the notch / cut <NUM> can be formed to match the shape of the connector hook <NUM>.

When connecting the optical fiber connector <NUM>, the optical fiber connector <NUM> can slide over the encasement <NUM>, and the connector hook <NUM> can connect into the notch / cut <NUM>. The connection between the connector hook <NUM> and the notch / cut <NUM> can create a mechanical stop, preventing the optical fiber connector <NUM> from moving towards or away from the chip package <NUM>. When a notch is used, the connection between the notch and the connector hook <NUM> may also prevent the optical fiber connector <NUM> from moving side-to-side, relative the chip package.

The connector hook <NUM> and the notch / cut <NUM> also facilitate self-alignment of the optical fiber connector <NUM> (and the optical fiber <NUM>) with the chip package <NUM>. By creating the notch / cut <NUM> in a predetermined position proximate the optical transducer <NUM> and/or the optical element <NUM>, the notch / cut <NUM> acts as a guide and hard stop for receiving the connector hook <NUM>.

In some embodiments, solder balls <NUM> are used to add further mechanical fixation between the optical fiber connector <NUM> and the base <NUM>.

<FIG> are schematic block diagrams illustrating an example process flow for forming an optical fiber accommodating chip package in accordance with embodiments of the present disclosure. In general, the process flow can include an embedded Wafer Level Ball Grid Array (eWI,B) process flow or other type of process flow that can include a separation (e.g., saw separation) and/or a mold pressing process.

As illustrated in <FIG>, the chips 402a-b, optical transducers 404a-b, and optical elements <NUM> are placed on a carrier <NUM> using an adhesive tape <NUM>. The chips 402a-b can be a storage or memory chip, processor, or other type of integrated circuit (<NUM>).

In some embodiments, the optical transducers 404a is structured such that each optical element <NUM> is adjacent to and in optical communication with an optical transducers 404a. In some embodiments, the optical transducers 404a-b are structured such that each optical element <NUM> is adjacent to and in optical communication with an optical transducers 404a-b (i.e., one optical transducer 404a on one side of the optical element <NUM> and one optical transducer 404b on the other side of the optical element <NUM>).

The arrangement of the chips 402a-b and the optical transducers 404a-b and the optical element <NUM> can be as follows. A chip 402a can reside adjacent to an optical transducer 404a. The optical transducer 404a can reside adjacent to the optical element <NUM>, such that the optical transducer 404a is between the chip 402a and the optical element <NUM>. The chip 402a and the optical transducer 404a can be electrical coupled through a redistribution layer, discussed later. A second optical transducer 404b can reside adjacent to the optical element <NUM>, such that the optical element <NUM> is between the optical transducer 404a and the optical transducer 404b. A chip 402b can reside adjacent to the optical transducer 404b, such that the optical transducer 404b is between the optical element <NUM> and the chip 402b. The chip 402b and the optical transducer 404b can be electrical coupled through a redistribution layer, discussed later.

A predetermined number of chips, optical transducers, and optical elements can be placed on the carrier <NUM> in the above described orientation, depending on the size of the carrier.

As illustrated in <FIG>, an encasement <NUM> (also referred to as a moldcap <NUM>) is formed (<NUM>). The encasement <NUM> can be formed using a eWLB molding process, or a similar process. The encasement <NUM> covers the chips, optical transducers, and optical elements. In some embodiments, the encasement <NUM> can hold the chips, optical transducers, and optical elements in place. The encasement <NUM> can be a mold compound, similar to that used in eWLB processing techniques. A liquid mold compound can be dispersed over the chips, the optical transducers, and the optical elements and then solidified using known techniques. A solid mold compound can be applied using compression molding or other techniques known in the art.

As illustrated in <FIG>, at least one notch <NUM> is formed in the encasement <NUM> (<NUM>). Notches <NUM> can be formed by pressing a toothed structure into the encasement. The toothed structure can be part of the mold case used when forming the encasement <NUM>, resulting in a notch in the top of the encasement at predetermined positions.

As illustrated in <FIG>, the encasement <NUM> and the chips and optical transducers and optical elements can be removed from the carrier <NUM> (<NUM>). Also shown in <FIG>, the encasement and the chips and optical transducers and optical elements can reside on a base <NUM> that is fabricated through semiconductor or other dielectric processing techniques. The base <NUM> can be dielectric material that includes a redistribution layer. The redistribution layer can be formed through patterned metal layer deposition or other similar techniques. The base <NUM> can include the redistribution layer shown in <FIG>. In some embodiments, solder balls <NUM> can be used to physically connect the chips and optical transducers to the base <NUM>. The solder balls can also provide electrical access to various interfaces on the chip and other electronics on the chip package.

As illustrated in <FIG>, the chip package can undergo singulation to isolate individual chip packages (<NUM>). Singulation can be similar to singulation techniques used in eWLB processing. For example, the chip package can be sawed through to singulate the chip package.

The chip package can be sawed through the center of each optical element, e.g., at a location <NUM>. This sawing location can result in the optical element being at an edge of each resulting singulated chip package. Further, the optical element, after singulation, is exposed to the air. Sawing is performed in such a manner that the optical element is cleanly cut. In some embodiments, the optical element can be polished after singulation.

As illustrated in <FIG>, the chip package can be sawed for singulation through optical elements for all of the optical elements on the original chip package (<NUM>).

<FIG> are schematic block diagrams illustrating another example process flow for forming an optical fiber accommodating chip package in accordance with embodiments of the present disclosure. <FIG> starts after the processes shown in <FIG>. As illustrated in <FIG>, the encasement <NUM> and the chip and optical transducers and optical elements have been lifted off of the carrier. In <FIG>, the chip package includes a base and includes solder balls to add physical stability between the chip and optical transducer and the base.

As illustrated in <FIG>, the chip package undergoes singulation by sawing through the encasement and the base at a location <NUM> through the optical element (<NUM>). In the same sawing process, the cuts <NUM> are made in the encasement. The cuts <NUM> will act as the receiver for the optical fiber connector. By using the saw to form the cuts <NUM>, the number of tools and steps can be reduced.

As illustrated in <FIG>, the sawing can result in both the cuts <NUM> in the encasement and the singulation of the chip package (<NUM>).

<FIG> are schematic diagrams illustrating an example process flow for forming an optical fiber accommodating chip package using flip-chip processing in accordance with embodiments of the present disclosure.

As illustrated in <FIG>, a set of chips 602a and 602b can be soldered to a prefabricated flip chip substrate that includes a redistribution layer (flip chip substrate + RDL) <NUM> (<NUM>). The resulting structure is illustrated in <FIG> (<NUM>). The RDL layer can be formed processing the flip chip substrate and designed to accommodate the chip pins and the optical transducer pins. The RDL can also provide landing pads for solder balls.

In some embodiments, the optical transducers 604a is structured such that each optical element <NUM> is adjacent to and in optical communication with an optical transducers 604a. In some embodiments, the optical transducers 604a-b are structured such that each optical element <NUM> is adjacent to and in optical communication with an optical transducers 604a-b (i.e., one optical transducer 604a on one side of the optical element <NUM> and one optical transducer 604b on the other side of the optical element <NUM>).

The arrangement of the chips 602a-b and the optical transducers 604a-b and the optical element <NUM> can be as follows. A chip 602a can reside adjacent to an optical transducer 604a. The optical transducer 604a can reside adjacent to the optical element <NUM>, such that the optical transducer 604a is between the chip 402a and the optical element <NUM>. The chip 602a and the optical transducer 604a can be electrical coupled through a redistribution layer, discussed later. A second optical transducer 604b can reside adjacent to the optical element <NUM>, such that the optical element <NUM> is between the optical transducer 604a and the optical transducer 604b. A chip 602b can reside adjacent to the optical transducer 604b, such that the optical transducer 604b is between the optical element <NUM> and the chip 602b. The chip 602b and the optical transducer 604b can be electrical coupled through a redistribution layer, discussed later.

A predetermined number of chips, optical transducers, and optical elements can be placed on the flip chip substrate + RDL <NUM> in the above described orientation, depending on the size of the substrate.

As illustrated in <FIG>, at least one notch <NUM> is formed in the encasement <NUM> (<NUM>). Notches <NUM> can be formed by pressing a toothed structure into the encasement. The toothed structure can be part of the mold case used when forming the encasement <NUM>, resulting in a notch in the top of the encasement at predetermined positions. In some embodiments, solder balls <NUM> can be used to physically connect the chips and optical transducers to the flip chip substrate + RDL <NUM>. The solder balls can also provide electrical access to various interfaces on the chip and other electronics on the chip package.

As illustrated in <FIG>, the encasement <NUM> and the chips and optical transducers and optical elements can be sawed to form singulated packages (<NUM>). The chip package can undergo singulation to isolate individual chip packages. Singulation can be similar to singulation techniques used in eWLB processing. For example, the chip package can be sawed through to singulate the chip package.

<FIG> are schematic diagrams illustrating another example process flow for forming an optical fiber accommodating chip package using flip-chip processing in accordance with embodiments of the present disclosure. As illustrated in <FIG>, the chip package undergoes singulation by sawing through the encasement and the flip-chip substrate + RDL <NUM> at a location <NUM> through the optical element (<NUM>). In the same sawing process, the cuts <NUM> are made in the encasement. The cuts <NUM> will act as the receiver for the optical fiber connector. By using the saw to form the cuts <NUM>, the number of tools and steps can be reduced.

<FIG> is a block diagram of an example computing device <NUM> that may include or be included in the flexible IC package <NUM> (e.g., as a wearable IC device). As shown, the computing device <NUM> may include one or more processors <NUM> (e.g., one or more processor cores implemented on one or more components) and a system memory <NUM> (implemented on one or more components). As used herein, the term "processor" or "processing device" may refer to any device or portion of a device that processes electronic data from registers and/or memory to transform that electronic data into other electronic data that may be stored in registers and/or memory. The processor(s) <NUM> may include one or more microprocessors, graphics processors, digital signal processors, crypto processors, or other suitable devices. More generally, the computing device <NUM> may include any suitable computational circuitry, such as one or more Application Specific Integrated Circuits (ASICs).

The computing device <NUM> may include one or more mass storage devices <NUM> (such as flash memory devices or any other mass storage device suitable for inclusion in a flexible IC package). The system memory <NUM> and the mass storage device <NUM> may include any suitable storage devices, such as volatile memory (e.g., dynamic random access memory (DRAM)), nonvolatile memory (e.g., read-only memory (ROM)), and flash memory. The computing device <NUM> may include one or more I/O devices <NUM> (such as display, user input device, network interface cards, modems, and so forth, suitable for inclusion in a flexible IC device). The elements may be coupled to each other via a system bus <NUM>, which represents one or more buses.

Each of these elements may perform its conventional functions known in the art. In particular, the system memory <NUM> and the mass storage device <NUM> may be employed to store a working copy and a permanent copy of programming instructions <NUM>.

The permanent copy of the programming instructions <NUM> may be placed into permanent mass storage devices <NUM> in the factory or through a communication device included in the I/O devices <NUM> (e.g., from a distribution server (not shown)). The constitution of elements <NUM>-<NUM> are known, and accordingly will not be further described.

Machine-accessible media (including non-transitory computer-readable storage media), methods, systems, and devices for performing the above-described techniques are illustrative examples of embodiments disclosed herein for thermal management of an IC device. For example, a computer-readable media (e.g., the system memory <NUM> and/or the mass storage device <NUM>) may have stored thereon instructions (e.g., the instructions <NUM>) such that, when the instructions are executed by one or more of the processors <NUM>.

As noted above, although the thermal management systems and techniques disclosed herein may be particularly advantageous when used to thermally manage flexible IC packages, these systems and techniques may also be implemented to improve thermal management of conventional, rigid IC packages. Thus, any of the embodiments disclosed herein and described as applicable in a flexible IC package may also apply in a conventional, rigid IC package setting. Such a rigid IC package may include, for example, a rigid substrate material and/or a rigid overmold material.

Additionally, although the thermal management systems and techniques disclosed herein may be particularly advantageous when used to thermally manage components (or "component sections," as discussed above), these systems and techniques may be used to thermally manage any devices included in an IC package, such as a resistor, capacitor, transistor, inductor, radio, memory, processor, laser, light-emitting diode (LED), sensor, a memory gate, combinational or state logic, or other digital or analog component. A device thermally managed by the thermal management systems and techniques disclosed herein may be a packaged component (e.g., a surface mount, flip chip, ball grid array, land grid array, bumpless buildup layer, or other package) or an unpackaged component.

Claim 1:
A method comprising:
providing (<NUM>) an optical transducer (<NUM>, <NUM>) and an optical element (<NUM>, <NUM>) adjacent to the optical transducer (<NUM>, <NUM>) on a carrier (<NUM>);
encasing (<NUM>) the optical transducer (<NUM>, <NUM>) and the optical element (<NUM>, <NUM>) with an encasement (<NUM>, <NUM>);
forming (<NUM>) a connector receiver (<NUM>, <NUM>, <NUM>, <NUM>) in the encasement (<NUM>, <NUM>) at a top side of the encasement (<NUM>, <NUM>) at a location proximate to the optical transducer (<NUM>, <NUM>), wherein the connector receiver (<NUM>, <NUM>, <NUM>, <NUM>) is for receiving a tooth (<NUM>) of an optical fiber connector (<NUM>); and
cutting (<NUM>) the encasement (<NUM>, <NUM>) and the optical element (<NUM>, <NUM>) to expose a side of the optical element (<NUM>, <NUM>), wherein the side of the optical element (<NUM>, <NUM>) is flush with the edge of the encasement (<NUM>, <NUM>).