Patent Description:
The described embodiments relate generally to photonic integrated circuits. More particularly, the present embodiments relate to systems and methods for producing photonic integrated circuits that can be assembled using controlled collapse chip connections.

Photonic integrated circuits include integrated optical circuits that employ photonic components that emit and/or absorb optical signals such as visible or infrared light. Photonic integrated circuits can include optical emitters such as laser emitters and can be manufactured using microfabrication techniques such as micromachining and lithography to create features of the photonic circuit on a substrate. Photonic components such as lasers may be coupled with the circuit at various stages in the manufacturing process and one or more steps may be performed after the addition of the photonic components such as coating to help protect these components from contamination or damage. Once assembled the photonic integrated circuit may be interconnected to other semi-conductor devices. Prior art optical devices in which a laser die is interposed between two substrates are inter alia known from <CIT> and <CIT>.

Embodiments are directed to an optical device including a first substrate defining a surface and a trench forming a depression along a portion of the surface, and a second substrate coupled with the surface and extending from the surface to form a raised portion around the trench. The optical device includes a laser die positioned within the trench, such that the laser die is surrounded by the second substrate, and an optical material positioned within a region between the laser die and the second substrate. The optical device further includes a third substrate coupled with the second substrate such that the second substrate is positioned between the first substrate and the third substrate. The second substrate is configured to at least partially isolate the laser die from mechanical stress exerted on the optical device.

In some embodiments the optical device further includes an optical output, a fill material positioned between the first substrate and the second substrate, and a fill dam configured to retain the fill material such that it does not cover the optical output. In some cases, the optical device includes a fill dam coupled with the third substrate and extending toward the first substrate. In some cases, a bottom edge of the fill dam is offset from the first substrate. The fill dam may be configured to retain a fill material within a space between the first substrate and the third substrate. In some embodiments, the optical device includes an interconnect formed from an electrically conductive material that is positioned on the third substrate. In some cases, the third substrate comprises a first surface that faces toward the first substrate and a second surface opposite the first surface, and the interconnect is positioned on the second surface. In further examples, the interconnect is electrically coupled to the laser die.

Embodiments described herein are also directed to a method of manufacturing an optical device, where the method includes forming a trench in a first substrate that defines a depression along a surface of the first substrate and forming a raised feature comprising a second substrate around the trench. The raised feature may extend from the surface. The method includes coupling a laser die to the first substrate such that the laser die is positioned within the trench and surrounded by the raised feature, and introducing a first optical material to a first region between the raised feature and the laser die. The method also includes coupling a third substrate to the raised feature such that the raised feature is positioned between the first substrate and the third substrate, and introducing a second material into a second region at least partially defined by the first substrate, the raised feature, and the third substrate.

In some embodiments, the method may further include forming a fill dam on the third substrate that extends toward the first substrate and is offset from the first substrate when the second substrate is coupled to the raised feature. In some cases, the method can include forming an interconnect on the second substrate, where the interconnect is positioned on an external surface of the third substrate and is coupled to the raised feature.

Embodiments described herein are also directed to an optical device, including a first substrate that defines a surface including a first electrical contact, and a trench forming a depression along a portion of the surface. The optical device can also include a laser die positioned within the trench and coupled with the first electrical contact, and a first material coupled with the laser die and at least a portion of the first substrate. A second substrate may be coupled to the first substrate and form a cavity around the laser die, and the second substrate can include a second electrical contact that is electrically coupled to the first electrical contact. An electrical interconnect can be coupled to an outer surface of the second substrate and electrically coupled with the second electrical contact. The invention is however only as defined in the appended claims.

In some embodiments, the first material forms a layer covering the laser die and at least a portion of the first substrate, the second substrate may be a silicon wafer, and the cavity can be etched from the silicon wafer. The electrical interconnect may include a solder based material that is configured to electrically couple the laser die with an electrical circuit. In some cases, the first material includes a conformal coating that covers the laser die and at least a portion of the first substrate. In some examples, the second substrate is formed from a silicon material, and the second substrate includes a via extending through the silicon material. The via may contain an electrically conductive material comprising the second electrical contact. In some cases, the electrical interconnect is at least partially positioned on an external surface of the second substrate.

Embodiments described herein include a method of forming an optical device, where the method includes forming a trench in a first substrate that defines a depression along a surface of the first substrate. The method may include depositing a first electrical contact onto the first substrate such that a first portion of the first electrical contact is located in the trench, and coupling a laser die to the first substrate such that the laser die is positioned within the trench. A first material may be applied over the laser die and at least a portion of the first substrate. In some cases, the method further includes coupling a second substrate to the first substrate such that a second electrical contact of the second substrate is electrically coupled with the first electrical contact. The second substrate may form a cavity around the laser die. The method may also include forming an electrical interconnect on an outer surface of the second substrate such that the electrical interconnect is electrically coupled to the second electrical contact.

In some embodiments, the second substrate is a silicon material, and the method may further include etching the second substrate to form at least a portion of the cavity in the silicon material. In some cases, the electrical interconnect is formed using a ball drop process to deposit a solder based material on the second substrate.

The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any characteristics attribute, or property for any element illustrated in the accompanying figures.

Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented there between, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto.

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the scope of the described embodiments as defined by the appended claims.

Embodiments described herein include an optical device such as a photonic integrated circuit (PIC) that includes optical components such as laser dice and structures for protecting the optical components. In a first set of embodiments, an optical device can include a first substrate material that has a depression defining a trench and a second substrate that forms a wall around the trench. An optical output such as a laser die may be positioned within the trench and a third substrate may be positioned on the wall formed by the second substrate. The trench, the wall, and the third substrate may form a cavity around the laser die. In some cases, the cavity may contain an optical fill material in the space defined by the trench, the wall, and the third substrate. Accordingly, the laser die may be isolated from contamination and protected from mechanical stress experienced by the optical device. In some embodiments, interconnects such as controlled collapse chip connections (also referred to as C4 or flip chip connections), copper pillar connections, gold stud bumps, or a combination thereof can be positioned on an outer surface of the third substrate. Thus, the optical device can be interconnected to other integrated circuits using C4 (flip chip), copper pillar, gold stud bump, or other suitable connection methods.

In some embodiments, a fill material may be introduced to a space between the first substrate and the third substrate. For example, the wall formed from the second substrate may offset the first substrate from the third substrate thereby creating a gap between these components. A fill material may be injected into this gap to fill the space between the first and the third substrates. In some cases, the optical device may include a fill dam to help control the location of the fill material within the gap. For example, the fill dam may be formed on the first substrate and extend toward the first substrate. The fill dam may define a structure that blocks the movement of the fill material. In some cases, the fill dam may be located near a facet or optical output of the optical device. Thus, the fill dam may prevent the fill material from covering or otherwise interfering with an optical output of the optical device.

In another set of embodiments, an optical device can include a first substrate material that has a depression defining a trench and a second substrate material that has a recessed feature. A laser die may be positioned within the trench and the first and second substrates can be joined to form a cavity around the laser die. The cavity can be defined by the trench in the first substrate and the recessed feature in the second substrate. The cavity may isolate the laser die from contamination and/or protect the laser die from mechanical stress experienced by the optical device. In some embodiments, interconnects (C4/flip chip) can be positioned on an outer surface of the second substrate. Thus, the optical device can be interconnected to other integrated circuits using C4 or flip chip connection methods.

<FIG> illustrates a top view of an optical device <NUM>, and <FIG> illustrates a cross-sectional view of the optical device taken along line A-A. As illustrated, multiple optical devices may be formed on a first substrate <NUM>, one of which is labeled for clarity. The optical device <NUM> can include a trench <NUM> that is defined by a depressed region in an upper surface of the first substrate <NUM>. A second substrate can define a wall <NUM> that is formed around the trench <NUM> and extends from the upper surface of the first substrate <NUM>. In some embodiments, the wall <NUM> can form a closed perimeter around the trench <NUM>. A photonic device such as a laser die <NUM> can be positioned within the trench <NUM> and surrounded by the wall <NUM>. The laser die <NUM> can be coupled to an electrical contact <NUM>, which can be coupled to a post <NUM> or interconnection bump; the term "post," as used herein, encompasses bumps as well. The post <NUM> can be formed from C4 interconnections, copper post connections, gold stud bump connections, or other suitable connections, and multiple posts <NUM> can be distributed along a surface of the first substrate <NUM>, for example, to form an array of posts <NUM>.

In some embodiments, the optical device <NUM> can include an optical fill material <NUM> in a region between the wall <NUM> and the laser die <NUM>. The optical fill material <NUM> can be introduced into the region between the wall <NUM> and the laser die <NUM> as a liquid/viscous material such that it conforms or at least partially conforms to the surfaces in this region formed by the wall <NUM> and the laser die <NUM>. The optical fill material <NUM> can be cured to form a solid or semi-solid structure around the laser die <NUM>. In some examples, the optical fill material <NUM> may not be cured until one or more additional processing steps have occurred such as adding additional structures/elements to the optical device <NUM> as described herein. The optical fill material <NUM> can include an optical underfill material, adhesive, or the like.

In some embodiments, the first substrate <NUM> can be formed from a silicon, ceramic, plastic, or other suitable material and the trench <NUM> can be machined, etched, or formed in the material using processes such as patterned lithography techniques. The second substrate, defining the wall <NUM>, can be formed from a variety of materials. For example, the wall <NUM> may be formed from an organic or ceramic substrate and be plated using copper and/or solder to create a structure that extends or is raised from the surface of the first substrate <NUM>. In cases where the wall <NUM> forms a closed perimeter around the trench <NUM>, the wall <NUM> and the trench <NUM> may form a first portion of a closed cavity around the laser die <NUM> that isolates the laser die <NUM>. The wall <NUM> can be configured to be more rigid than the laser die <NUM>, such that the wall <NUM> can isolate/protect the laser die <NUM> from mechanical stress or other physical disturbances. In some examples, a top of the wall <NUM> may extend to a height of the top of the laser die <NUM> when the laser die is positioned with in the trench <NUM> and is coupled with the first substrate <NUM>. In some cases, the wall <NUM> can extend above the laser die <NUM> such that a top of the wall <NUM> is above a top of the laser die <NUM>.

In some embodiments, the wall <NUM> is formed using repassivation techniques with materials that can include polyimide, polybenzocyclobutene, or benzocyclobutene, and a redistribution layer that can be formed by metal pattern plating processes that includes forming C4 solder bumps, metal studs, or metal pillars (collectively, "posts"). In some cases, forming the wall can include forming passivation layers on one or more of these components. In some examples, the bump, stud, and/or pillar heights can be between about <NUM> and about <NUM> micrometers, the redistribution layer thickness can be between about <NUM> micrometer and about <NUM> micrometers, and the passivation thickness can be between about <NUM> micrometer and about <NUM> micrometers.

<FIG> illustrates a cross-sectional view of an optical device <NUM> taken along line A-A and further including a third substrate <NUM>, a fill material <NUM>, a fill dam <NUM> and an optical output <NUM>. The optical device <NUM> may be an example of the optical device <NUM> and can include a first substrate <NUM> having a trench <NUM>, a wall <NUM> positioned around the trench <NUM>, a laser die <NUM> positioned within the trench <NUM>, and an optical fill material <NUM> as described with reference to <FIG>. The third substrate <NUM> may be positioned on top of the wall <NUM> such that it is offset from the first substrate <NUM>. The fill material <NUM> may be located between the first substrate <NUM> and the third substrate <NUM>. The fill dam <NUM> may extend from the third substrate <NUM> and towards the first substrate <NUM>, and the optical output <NUM> may be located on the first substrate <NUM>.

In some embodiments, the third substrate <NUM> may form a layer of material that is coupled with the second substrate forming the wall <NUM>. The third substrate <NUM> may be formed from a silicon, ceramic, organic, or other suitable material and may partially define a space that is defined by an upper surface of the first substrate <NUM>, an outer surface of the wall <NUM>, and a lower surface of the third substrate <NUM>. The third substrate <NUM> may be at least partially supported by the wall <NUM>. The third substrate <NUM> may also be coupled with the post <NUM> (which may be an interconnection bump) using C4, copper pillar, or gold stud bump connection techniques. In some embodiments, a fill material <NUM> can be introduced into the space between the first substrate <NUM>, the wall <NUM>, and the third substrate <NUM>. The fill material <NUM> can be introduced as a liquid or viscous material and be injected or flow into the space defined by the first substrate <NUM>, the wall <NUM>, and the third substrate <NUM>. The fill material <NUM> can be cured such that it hardens to form a more structurally rigid material. In some cases, the optical fill material <NUM> and the fill material <NUM> can be cured at the same or similar times to couple the third substrate <NUM> to the wall <NUM> and the first substrate <NUM>. The fill material <NUM> can include an optical underfill material, adhesive, or the like.

The combination of the wall <NUM> and the fill material <NUM> can create a structural support between the first substrate <NUM> and the third substrate <NUM> such that the laser die <NUM> is isolated and/or protected from mechanical stress. In some cases, the optical fill material <NUM>, the first substrate <NUM>, the wall <NUM>, and the third substrate <NUM> can also protect the laser die <NUM> from contaminants such as dust, debris, moisture, and the like.

In some embodiments, the fill dam <NUM> can be positioned along the third substrate <NUM> and extend towards the first substrate <NUM>. The fill dam <NUM> can help retain the fill material <NUM> within the space between the first substrate <NUM> and the third substrate <NUM> such that the fill material does not cover the optical output <NUM>. For example, the fill dam <NUM> may extend towards an upper surface of the first substrate <NUM> such that there is a smaller gap between the first substrate <NUM> and the fill dam <NUM> than there is between the first substrate <NUM> and the third substrate <NUM>. In some examples, the fill dam <NUM> can form a gap with the first substrate <NUM> that is between <NUM> micrometers and <NUM> micrometers. Accordingly, as fill material <NUM> is introduced into the optical device <NUM> (through injection, surface tension, or other technique), the fill dam <NUM> may prevent the fill material <NUM> from spreading over the optical output <NUM>. In some cases, the size and positioning of the fill dam <NUM> may be based on one or more properties of the fill material <NUM> such as a viscosity, surface tension, and so on. In some cases, the optical output <NUM> may include a facet.

<FIG> illustrates a cross-sectional view of an optical device <NUM> taken along line A-A and also including one or more interconnects <NUM> positioned along an upper surface of the third substrate <NUM>. The optical device <NUM> may be an example of the optical devices <NUM> and <NUM> and can include a first substrate <NUM> having a trench <NUM>, a wall <NUM> positioned around the trench <NUM>, a laser die <NUM> positioned within the trench <NUM>, an optical fill material <NUM>, a third substrate <NUM>, a fill material <NUM>, a fill dam <NUM> and an optical output <NUM> as described with reference to <FIG> and <FIG>.

In some embodiments, the interconnects <NUM> can be deposited on an upper surface of the third substrate <NUM>. The interconnects <NUM> can be formed from solder, copper, gold, or other suitable materials, or a combination thereof, and used for bonding the optical device to another device such as another integrated circuit that may be used to drive the laser die <NUM>. In some embodiments, the interconnects <NUM> can be configured to allow for flip chip (C4) bonding of the optical device to other wafer devices. In some embodiments, one or more interconnects <NUM> may be electrically coupled with the post <NUM> (and electrical contact <NUM>) such that the interconnect <NUM> is electrically coupled to the laser die <NUM>.

In some embodiments, one or more portions of a chip may be divided such that different optical devices <NUM> that were formed on a single chip can be separated in multiple discrete optical devices <NUM>. After the separation, the optical devices may undergo inspections such as a visual inspection to confirm that they are ready to be bonded to other devices such as other integrated circuits using flip chip (C4) bonding techniques.

<FIG> illustrates an example method <NUM> for manufacturing an optical device such as the optical devices <NUM>, <NUM>, and <NUM> described with reference to <FIG>. At <NUM>, the method <NUM> may include forming a trench in a first substrate that defines depression along a surface of the first substrate. For example, the first substrate may include a silicon material and the trench may be etched, machined, or formed using other suitable processes such as lithographic patterning processes. In some cases, the depth of the trench may be defined based on a size of a photonic device such as a laser die that is to be at least partially located within the trench. The trench may form a first portion of a cavity that surrounds the laser die. In some cases, conductive traces may be created in the trench that are used to couple the laser die to one or more driver circuits.

At <NUM>, the method <NUM> may include forming a raised feature using a second substrate, which may be the same or different material as the first substrate. The second substrate can form a wall around the trench that extends from the surface of the first substrate. The raised feature may be formed from an organic or ceramic material or other suitable materials. In some cases, the raised feature may be coated with copper, solder, gold, or a combination thereof, which may be used to couple the raised feature to one or more other components of the optical device. The raised feature may at least partially isolate a photonic component such as a laser die from the surrounding environment, and/or provide protection from mechanical stress applied to the optical device.

At <NUM>, the method <NUM> can include coupling a laser die to the first substrate such that the laser die is positioned within the trench defined by the first substrate. In some cases, the laser die may be coupled with electrical traces/contacts that are located within the trench. The laser die may be partially surrounded by the trench. In some cases, the laser die may also be partially surrounded by the raised feature that surrounds the trench.

At <NUM>, the method <NUM> may include introducing a first optical material into a first region between the raised feature and the laser die. The optical fill material may include a liquid/viscous material that can flow around the laser die and trench to conform to features of the laser die and the trench. In some cases, the optical fill material may be cured after settling into the region between the laser die and the trench. In some examples, the optical fill material may be transparent when cured such that light emitted from the laser die can pass through the cured optical fill material. The optical fill material may stabilize the laser die in place, protect it from contamination (dust, debris, moisture and the like), and help isolate the laser die from mechanical stress or other physical disruptions.

At <NUM>, the method <NUM> may include coupling a third substrate to the raised feature such that the raised feature is positioned between the first substrate and the third substrate. In some cases, coupling the third substrate to the raised feature may be accomplished using physical connections such as a solder, gold, or copper materials, the optical fill material, or other fill materials as described herein. The third substrate may be offset from the first substrate by the raised feature to form a space or region between the first and second substrates.

At <NUM>, the method <NUM> can include introducing a second fill to a second region at least partially defined by the first substrate, the second substrate, and the raised feature. The second material may be introduced to the second region as a liquid and be injected or flow into the second region via surface tension forces, or other suitable processes. Once in place, the fill material can be cured to transform it to a solid material, which can include heat curing, light curing, or other suitable methods.

In some embodiments, the method <NUM> may include forming a fill dam on the third substrate such that the fill dam extends toward the first substrate and is offset from the first substrate. A lower edge of the fill dam may form a smaller gap with the first substrate that prevents or resists the fill material from moving past the fill dam. The fill damn may be used to control where fill material can move to within the second region and prevent the fill material from covering an optical output of the optical device such as a facet. In some cases, the method <NUM> can include forming one or more interconnects on an outer surface of the second substrate. The interconnects may be used to couple the optical device to other devices using flip chip (C4) bonding techniques.

<FIG> illustrates a top view of an optical device <NUM> and <FIG> illustrates a cross-sectional view of the optical device <NUM> taken along line B-B. The optical device <NUM> can be an example of a photonic integrated circuit having an optical output, such as a laser die <NUM>, protected by a capping substrate such as a silicon capping wafer (which may be referred to as a second substrate <NUM>). As illustrated, multiple optical devices may be formed on a first substrate <NUM>, one of which is labeled for clarity. In some cases, the first substrate is a silicon photonics substrate. The optical device <NUM> can include an optical facet <NUM> and a trench <NUM> that is defined by depressed regions in an upper surface of the first substrate <NUM>. The optical facet <NUM> and/or the trench <NUM> can be formed in the first substrate <NUM> using etching techniques or other suitable processes, such as those described herein with respect to the trench <NUM>, or any other suitable process. A second substrate <NUM>, which may be an example of a silicon capping substrate or wafer, can be coupled with the first substrate to form one or more cavities in the optical device <NUM>. The second substrate <NUM> can be a silicon capping wafer and a facet can be located within a first cavity of the wafer. Similarly, the laser die <NUM> can be located within a second cavity formed by coupling the first substrate <NUM> (e.g., the silicon photonics substrate) and the second substrate <NUM>. The cavity can isolate photonic components, such as the facet <NUM> and the laser die <NUM> from the surrounding environment, which can protect these components from mechanical stress applied to the optical device, protect them from other physical damage, and isolate them from contamination, debris, and so on.

In some embodiments, a first material, which can include an optical underfill, can couple the laser die <NUM> to the first substrate <NUM> and/or the second substrate <NUM>. The first material can encapsulate the laser die <NUM> to protect the laser die such as by reducing stress between the laser die <NUM> and the first substrate <NUM>. The laser die <NUM> can also be coupled with a first electrical contact <NUM>, which can be partially located in the trench <NUM>. In some embodiments, the second substrate <NUM> can include a second electrical contact <NUM>, which can be coupled to the first electrical contact <NUM>.

In some embodiments, the first substrate <NUM> can be formed from a silicon material (or any other suitable material, which may include a ceramic or plastic) and the trench <NUM> can be machined, etched, or formed in the silicon material using any suitable processes such as patterned lithography techniques. The second substrate <NUM> can be formed from a silicon material and the second substrate <NUM> can be etched, machined, or manufactured using other suitable techniques to create a recess <NUM> in the second substrate <NUM> that forms an upper portion of the cavity. Etching of the first substrate <NUM> and/or the second substrate <NUM> can be performed along crystalline planes in the silicon material. In some embodiments, the trench <NUM> can be created in the first substrate, and independently, the recess <NUM> can be created in the second substrate <NUM>. The first substrate <NUM> and the second substrate <NUM> can be joined to form the cavity. The first substrate <NUM> and the second substrate <NUM> can be bonded together using solder based connections, or other suitable methods such as adhesive bonding. In some embodiments, the second substrate (e.g., the capping wafer) may be formed from a material other than silicon.

In some embodiments, the laser die <NUM> can be positioned within the trench <NUM> and coupled to the first substrate <NUM> prior to bonding the first substrate <NUM> with the second substrate <NUM>. In some embodiments, the facet <NUM> is also formed in the first substrate <NUM> and also contained within the recess <NUM> that is formed after joining the first substrate <NUM> and the second substrate <NUM>. In other cases, the optical facet <NUM> can be located in a different cavity from the laser die. The first electrical contact <NUM> can be deposited onto the first substrate <NUM> and the laser die <NUM> can be bonded to the first electrical contact <NUM>. The first electrical contact <NUM> can include electrically conductive traces that are partially located within the trench <NUM>. In some cases, the first electrical contact <NUM> can also be positioned along a portion of the first substrate <NUM> that is adjacent the trench <NUM>. In some embodiments, a first material <NUM>, such as an optical underfill, can be deposited around the laser die <NUM> and a portion of the first substrate <NUM> to form a layer/coating that covers the laser die <NUM>, which may help protect the laser die <NUM> from contaminants such as dust, debris, moisture, or the like.

When the first substrate <NUM> is coupled with the second substrate <NUM>, the cavity/cavities around the facet <NUM> and/or laser die <NUM> may protect the facet <NUM> and laser die <NUM> from contaminants (dust, debris, moisture, etc.), mechanical stress, or other physical disruptions. For example, the first substrate <NUM> and the second substrate <NUM> may form a protective barrier around the facet <NUM> and/or the laser die <NUM>.

In some embodiments, the second substrate <NUM> can include a via that comprises at least a portion of the second electrical contact <NUM>. The second electrical contact <NUM> may couple to the first electrical contact <NUM> and also include a portion of electrically conductive material that is located on an external surface of the second substrate <NUM>. Thus, the second electrical contact <NUM> may be used to electrically couple the laser die <NUM> (or other photonic component) to an external device such as an integrated circuit that is used to drive the laser die <NUM>.

<FIG> illustrates a cross-sectional view of an optical device <NUM> taken along line B-B and further comprising one or more electrical interconnects <NUM>. The optical device <NUM> can be an example of the optical device <NUM> and include the first substrate <NUM>, the second substrate <NUM>, the facet <NUM>, the laser die <NUM>, the first electrical contact <NUM>, and the second electrical contact <NUM> described with reference to <FIG>.

In some embodiments, the interconnects <NUM> can be deposited on an upper surface of the second substrate <NUM>. The interconnects <NUM> can be formed from a solder based material and used for bonding the optical device to another device such as another integrated circuit that may be used to drive the laser die <NUM>. In some embodiments, the interconnects <NUM> can be configured to allow flip chip (C4) bonding, copper pillar bonding, or gold stud bump bonding of the optical device to other wafer devices. In some embodiments, one or more interconnects <NUM> may be electrically coupled with the second electrical contact <NUM> (and the first electrical contact <NUM>) such that the interconnect <NUM> is electrically coupled to the laser die <NUM>. Thus, the interconnects <NUM> may be used to connect the laser die <NUM> to other devices (other integrated circuits) that are used to drive the laser die <NUM>.

<FIG> illustrates an example method <NUM> for manufacturing an optical device such as the optical devices <NUM> and <NUM> described with reference to <FIG> and <FIG>. At <NUM>, the method <NUM> may include forming a trench in a first substrate that defines a depression along a surface of the first substrate. For example, the first substrate may include a silicon material and the trench may be etched, machined, or formed using other suitable processes such as lithographic patterning processes. In some cases, the depth of the trench may be defined based on a size of a photonic device such as a laser die that is to be at least partially located within the trench. The trench may form a first portion of a cavity that surrounds the laser die. In some cases, an optical facet can be formed in the first substrate using etching, machining, or other suitable techniques.

At <NUM>, the method <NUM> may include depositing a first electrical contact onto the first substrate such that at least a portion of the electrical contact is located in the trench. In some cases, the first electrical contact may include one or more conductive traces positioned in the trench that are used to couple the laser die to one or more driver circuits. The first electrical contact may extend from the trench and along a portion of the first substrate, for example, to a location where a via from another layer will interface with the first substrate.

At <NUM>, the method <NUM> can include coupling a laser die to the first substrate such that the laser die is positioned within the trench defined by the first substrate. In some cases, the laser die may be coupled with first electrical contact/traces that are located within the trench. The laser die may be partially surrounded by the trench.

At <NUM>, the method <NUM> may include applying a first material over the laser die and at least a portion of the first substrate. In some cases, the first material may include a conformal coating that covers the laser die. The first material may be selected to protect the laser die from contamination such as dust, debris, or moisture.

At <NUM>, the method <NUM> may include coupling a second substrate to the first substrate such that a second electrical contact of the second substrate is electrically coupled with the first electrical contact. In some cases, the second substrate may have a via that includes the second electrical contact and the via may align with the first electrical contact to provide an electrical path from the laser die to an external surface of the second substrate.

At <NUM>, the method <NUM> may include forming an electrical interconnect on an outer surface of the second substrate such that the electrical interconnect is electrically coupled to the second electrical contact. The interconnects may include a solder based material or other suitable electrically conductive material that can be used to couple the optical device to other devices using flip chip (C4), copper pillar, gold stud bump, or other bonding techniques.

<FIG> illustrates an example block diagram of an optical device <NUM>, which may in some cases take the form of any of the optical devices as described with reference to <FIG>. The optical device can include a processor <NUM>, an input/output (I/O) mechanism <NUM> (e.g., an input/output device, such as a touch screen, crown or button, input/output port, or haptic interface), one or more optical units <NUM> (e.g., a photonic device such as a laser die), memory <NUM>, sensors <NUM> (e.g., an optical sensing system), and a power source <NUM> (e.g., a rechargeable battery). The processor <NUM> can control some or all of the operations of the optical device <NUM>. The processor <NUM> can communicate, either directly or indirectly, with some or all of the components of the optical device <NUM>. For example, a system bus or other communication mechanism <NUM> can provide communication between the processor <NUM>, the I/O mechanism <NUM>, the optical unit <NUM>, the memory <NUM>, the sensors <NUM>, and the power source <NUM>.

The processor <NUM> can be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processor <NUM> can be a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices. As described herein, the term "processor" is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or other suitable computing element or elements.

It should be noted that the components of the optical device <NUM> can be controlled by multiple processors. For example, select components of the optical device <NUM> (e.g., a sensor <NUM>) may be controlled by a first processor and other components of the optical device <NUM> (e.g., the optics unit <NUM>) may be controlled by a second processor, where the first and second processors may or may not be in communication with each other.

The I/O mechanism <NUM> can transmit and/or receive data from a user or another electronic device. An I/O device can include a display, a touch sensing input surface, one or more buttons (e.g., a graphical user interface "home" button), one or more cameras, one or more microphones or speakers, one or more ports, such as a microphone port, and/or a keyboard. Additionally or alternatively, an I/O device or port can transmit electronic signals via a communications network, such as a wireless and/or wired network connection. Examples of wireless and wired network connections include, but are not limited to, cellular, Wi-Fi, Bluetooth, IR, and Ethernet connections.

The memory <NUM> can store electronic data that can be used by the optical device <NUM>. For example, the memory <NUM> can store electrical data or content such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, and data structures or databases. The memory <NUM> can be configured as any type of memory. By way of example only, the memory <NUM> can be implemented as random access memory, read-only memory, Flash memory, removable memory, other types of storage elements, or combinations of such devices.

The optical device <NUM> may also include one or more sensors <NUM> positioned almost anywhere on the optical device <NUM>. The sensor(s) <NUM> can be configured to sense one or more type of parameters, such as but not limited to, pressure, light, touch, heat, movement, relative motion, biometric data (e.g., biological parameters), and so on. For example, the sensor(s) <NUM> may include a heat sensor, a position sensor, a light or optical sensor, an accelerometer, a pressure transducer, a gyroscope, a magnetometer, a health monitoring sensor, and so on. Additionally, the one or more sensors <NUM> can utilize any suitable sensing technology, including, but not limited to, capacitive, ultrasonic, resistive, optical, ultrasound, piezoelectric, and thermal sensing technology.

The power source <NUM> can be implemented with any device capable of providing energy to the optical device <NUM>. For example, the power source <NUM> may be one or more batteries or rechargeable batteries. Additionally or alternatively, the power source <NUM> can be a power connector or power cord that connects the optical device <NUM> to another power source, such as a wall outlet.

Claim 1:
An optical device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), comprising:
a first substrate defining:
a surface; and
a trench (<NUM>, <NUM>) forming a depression along a portion of the surface;
a second substrate (<NUM>) coupled with the surface and extending from the surface to form a raised portion around the trench (<NUM>, <NUM>);
a laser die (<NUM>, <NUM>) positioned within the trench (<NUM>, <NUM>), such that the laser die (<NUM>, <NUM>) is surrounded by the second substrate (<NUM>);
an optical material positioned within a region between the laser die (<NUM>, <NUM>), the first substrate (<NUM>, <NUM>), and the second substrate (<NUM>); and
a third substrate (<NUM>) coupled with the second substrate (<NUM>) such that the second substrate (<NUM>) is positioned between the first substrate (<NUM>, <NUM>) and the third substrate (<NUM>); wherein:
the second substrate (<NUM>) is configured to at least partially isolate the laser die (<NUM>, <NUM>) from mechanical stress exerted on the optical device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>).