# Patent

## Title
Manufacture including substrate and package structure of optical chip

## Abstract

A manufacture includes a package structure, a first substrate, and a conductive member of a same material. The package structure includes a chip comprising a conductive pad, a conductive structure over the chip, and a passivation layer over the conductive structure. The passivation layer has an opening defined therein, and the opening exposes a portion of a planar portion of the conductive structure. The first substrate includes a first surface defining a first reference plane and a second surface defining a second reference plane. The conductive member extends across the first reference plane and the second reference plane and into the opening. The conductive member is electrically coupled to the exposed portion of the planar portion.

## Background
RELATED APPLICATIONS
The instant application is related to U.S. patent application Ser. No. 14/015,513, filed Aug. 30, 2013, titled PACKAGE AND METHOD FOR INTEGRATION OF HETEROGENEOUS INTEGRATED CIRCUITS. The entire contents of the above-referenced application are incorporated by reference herein.
BACKGROUND
Optical signals are usable for high speed and secure data transmission between two devices. In some applications, a device capable of optical data transmission includes at least an integrated circuit (IC or “chip”) having an optical component for transmitting and/or receiving optical signals. Also, the device usually has one or more other optical or electrical components, a waveguide for the transmission of the optical signals, and a support, such as a substrate of a printed circuit board, on which the chip equipped with the optical component and the one or more other components are mounted. Various approaches for mounting a chip equipped with an optical component on a substrate have been studied.



DESCRIPTION OF THE DRAWINGS
One or more embodiments are illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout.
FIG. 1 is a cross-sectional view of a package structure in accordance with one or more embodiments.
FIGS. 2-7 are cross-sectional view of various manufactures in accordance with one or more embodiments.



DETAILED DESCRIPTION
It is understood that the following disclosure provides one or more different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, examples and are not intended to be limiting. In accordance with the standard practice in the industry, various features in the drawings are not drawn to scale and are used for illustration purposes only.
Moreover, spatially relative terms, for example, “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top,” “bottom,” “left,” “right,” etc. as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of the present disclosure of one features relationship to another feature. The spatially relative terms are intended to cover different orientations of the device including the features.
In some applications, a chip having an optical component (also referred to as an optical chip) is encapsulated by a molded package structure, and the molded package structure is mounted on a PCB substrate. Compared with a configuration without using the molded package structure, the embodiments described herein allow a shortened conductive path between the optical chip and the PCB. In some embodiments, shortened conductive path means lowered parasitic capacitance and resistance along the conductive path, and thus in turn helps to decrease power loss and increase operation frequency of the resulting device. In some embodiments using an interposer to connect the molded package structure and the PCB substrate, a through-silicon-via structure formed in the interposer is capable of being fabricated after mounting the molded package structure to the interposer (i.e., “via-last” process). By doing so, fabrication processes and masks for forming bump structures on corresponding sides of the interposer and the molded package structure are omitted.
FIG. 1 is a cross-sectional view of a package structure 100 in accordance with one or more embodiments. Package structure 100 includes a first chip 110, a second chip 120, a first passivation layer 130, a redistribution structure 140 over first passivation layer 130, and a second passivation layer 150 over redistribution structure 140. Package structure 100 further includes a molding structure 160 surrounding and underneath first chip 110 and second chip 120.
In some embodiments, first chip 110 includes one or more active components and/or passive components configured to process, receive and/or transmit electrical signals. Examples of passive components include, but are not limited to, resistors, capacitors, and inductors. Examples of active components include, but are not limited to, diodes, field effect transistors (FETs), metal-oxide-semiconductor FETs (MOSFETs), complementary metal-oxide-semiconductor (CMOS) transistors, and bipolar transistors. In some embodiments, first chip 110 includes a bare chip or die. In some embodiments, first chip 110 includes a stack of chips. In some embodiments, first chip 110 is configured to perform predetermined logic, analog, or mixed mode functionality. In some embodiments, first chip 110 has a thickness ranging from 50 μm to 750 μm.
First chip 110 includes at least one conductive pad 112 on an upper surface 114 of first chip 110. Conductive pad 112 is electrically coupled to the one or more active components and/or passive components of first chip 110 for communication of electrical signals between first chip 110 and external circuitry. Example materials of the conductive pad 112 include, but are not limited to, aluminum, copper, or a combination thereof. First chip 110 further has a passivation layer 116 over the upper surface 114. Passivation layer 116 has an opening that exposes at least a portion of conductive pad 112. Example materials of the passivation layer 116 include, but are not limited to, silicon oxide, silicon nitride, low dielectric constant (low-)k dielectric materials such as carbon doped oxides, extremely low-k dielectric materials such as porous carbon doped silicon dioxide, or a combination thereof.
Second chip 120 includes at least one optical component 122 configured to process, receive, and/or transmit optical signals. Second chip 120 is thus also being referred to as an optical chip in some applications. Optical signals are electromagnetic signals exhibiting a characteristic capable of being modeled by photons and are different from electrical signals which are signals carried by electrical charges, such as electrons, holes, or ions. In some embodiments, optical signals include electromagnetic signals having a wavelength less than 1 mm. Examples of optical components include, but are not limited to, light emitting devices such as lasers and light emitting diodes, light detecting devices such as photo-sensors, optical modulators, and optical couplers. In at least one embodiment, second chip 120 further includes one or more active and/or passive components configured to process, receive and/or transmit electrical signals converted to/from optical signals by the optical component 122. In some embodiments, second chip 120 has a thickness ranging from 100 μm to 350 μm.
Second chip 120 includes at least one conductive pad 124 on an upper surface 126 of first chip 120. Second chip 120 also has a passivation layer 128 over upper surface 126 and exposing a portion of conductive pad 124. Example materials of the conductive pad 124 include, but are not limited to, aluminum, copper, gold, or a combination thereof. Example materials of the passivation layer 128 include, but are not limited to, silicon oxide, silicon nitride, low-k dielectric materials such as carbon doped oxides, extremely low-k dielectric materials such as porous carbon doped silicon dioxide, or a combination thereof. In some embodiments, passivation layer 128 and passivation layers 130 and 150 have an opening 170 defined therein to allow transmitting and/or receiving of optical signals by the optical component 122. In at least one embodiment, passivation layer 128 is made of a material transparent to optical signals transmitted and/or received by the optical component 122, and a portion of the opening 170 corresponding to the passivation layer 128 is thus omitted.
Passivation layer 130 is over and covering conductive pads 112 and 124 and passivation layers 116 and 128. In some embodiments, passivation layer 130 includes epoxy, polyimide, benzocyclobutene (BCB), polybenzoxazole (PBO), or other organic dielectric materials. In one or more embodiments, passivation layer 130 is formed of a material similar to the material used for forming passivation layers 116 or 128, such as silicon oxides, silicon nitrides, low-k dielectric materials, extremely low-k dielectric materials, or a combination thereof. In at least one embodiment, passivation layer 130 is made of a material transparent to optical signals transmitted and/or received by the optical component 122, and a portion of the opening 170 corresponding to the passivation layer 130 is thus omitted. In some embodiments, passivation layer 130 has a thickness ranging from 3 μm to 10 μm.
Redistribution structure 140 includes a first conductive structure 142 electrically coupled to the conductive pad 112 and a second conductive structure 144 electrically coupled to the conductive pad 124. In the embodiment depicted in FIG. 1, first conductive structure 142 and second conductive structure 142 are connected and in physical contact at a reference line 146. First conductive structure 142 includes a planar portion 142a substantially in parallel with upper surface 114 of first chip 110 and a protrusion 142b connecting the conductive pad 112 and the planar portion 142a. Second conductive structure 144 includes a planar portion 144a substantially in parallel with upper surface 126 of second chip 120 and a protrusion 144b connecting the conductive pad 124 and the planar portion 144a. In the embodiment depicted in FIG. 1, planar portions 142a and 144b are in physical contact with each other at reference line 146. In some embodiments, planar portions 142a and 144b are not in physical contact with each other.
In some embodiments, conductive structures 142 and 144 include copper, aluminum, nickel, gold, tungsten, or a combination thereof. In some embodiments, conductive structures 142 and 144 each has one or more conductive layers suitable for obscuring metal atoms from diffusion into structures above or underneath redistribution structure 140. In some embodiments, conductive structures 142 and 144 are also referred to as post-passivation interconnect (PPI) structures. In some embodiments, conductive structures 142 and 144 are formed using a CMOS Back-End-of-Line (BEOL) process.
Passivation layer 150 is over and covering redistribution structure 140. In some embodiments, passivation layer 150 includes epoxy, polyimide, benzocyclobutene (BCB), polybenzoxazole (PBO), or other organic dielectric materials. In one or more embodiments, passivation layer 150 is formed of a material similar to the material used for forming the passivation layers 116 or 128, such as silicon oxides, silicon nitrides, low-k dielectric materials, extremely low-k dielectric materials, or a combination thereof. In some embodiments, passivation layer 150 and passivation layer 130 are made of different materials. In at least one embodiment, passivation layer 150 is made of a material transparent to optical signals transmitted and/or received by the optical component 122, and a portion of the opening 170 corresponding to the passivation layer 150 is thus omitted. In some embodiments, passivation layer 150 has a thickness ranging from 3 μm to 10 μm.
Molding structure 160 is surrounding and underneath first chip 110 and second chip 120 to protect surfaces of chips 110 and 120 that are not covered by passivation layers 130 and 150. In some embodiments, molding structure 160 has a thickness that is sufficient to enclose bottom surfaces of chips 110 and 120. In some embodiments, molding structure 160 comprises a material that has a thermal expansion coefficient about or between those of chips 110 and 120. In some embodiments, molding structure 160 comprises a material that has a thermal expansion coefficient ranging from 4 to 9. In some embodiments, example materials of the molding structure 160 include, but are not limited to silicone rubber, epoxy resins, other resins, or other epoxy materials.
Although only one conductive pad 112 or 124 for each chip 110 or 120 and only two corresponding conductive structures 142 and 144 are depicted in FIG. 1, in some embodiments, there are more than one conductive pad on each chip 110 or 120 and are variously connected by redistribution structure 140. In some embodiments, there are one or more other chips in addition to chips 110 and 120 included in the package structure 100. In some embodiments, only one of first chip 110 and second chip 120 is present, and the other one of first chip 110 and second chip 120 is omitted.
FIG. 2 is a cross-sectional view of a first example manufacture 200 having a package structure 100A mounted on a printed circuit board (PCB) 210 in accordance with one or more embodiments. Components of package structure 100A that are similar to those of package structure 100 are given the same reference numbers, and detailed description thereof is omitted.
Manufacture 200 includes PCB 210, an interposer 220 mounted on PCB 210, and package structure 100A mounted on interposer 220. PCB 210 includes a substrate 212, a conductive pad 214 on the substrate 212, and a passivation layer 216 over and exposing a portion of conductive pads 214. Interposer 220 includes a substrate 222, and substrate 222 includes a first surface 222a defining a first reference plane A, a second surface 222b defining a second reference plane B, a third surface 222c between the first and second reference planes, and a tilt surface 222d connecting the first and third surfaces. Interposer substrate 220 also includes a conductive pad 224 on the second surface 222b and passivation layer 226 on and exposing a portion of the conductive pads 224. The exposed portions of conductive pads 214 and 224 are physically and electrically connected by one or more corresponding solder balls 232 and 234.
In some embodiments, a thickness between first surface 222a and second surface 222b ranges from 40 μm to 200 μm. In some embodiments, a thickness between third surface 222c and first surface 222a ranges from 20 μm to 100 μm.
Package structure 100A has openings 242 and 244 defined in the passivation layer 150 and exposing a portion of corresponding conductive pads 142 and 144. Package structure 100A is mounted on first surface 222a of the substrate 222. In some embodiments, package structure 100A is attached to first surface 222a by a layer of adhesive material (not shown) disposed therebetween. Interposer 200 further includes one or more conductive members 252 and 254 of a same material extending across the first reference plane A and the second reference plane B and into the openings 242 and 244. Conductive members 252 and 254 are electrically coupled to the exposed portion of the planar portions of conductive structures 142 and 144 and conductive pad 224. In some embodiments, conductive structures 142 and 144 are not electrically coupled with each other through conductive members 252 and 254. In some embodiments, there are more or less than two conductive members 252 and 254 in interposer 220. In some applications, conductive members 252 and 254 are via structures through substrate 222. In some embodiments, conductive members 252 and 254 are formed after package structure 100A is mounted on the substrate 222.
Manufacture 200 further includes a reflective structure 262 on the tilt surface 222d of the substrate 222 and a waveguide 264 on the third surface 222c of the substrate 222. Waveguide 264 includes a core region 264a and a cladding region 264b. In some embodiments, core region 264a and cladding region 264b have different reflective coefficients and are arranged to allow an optical signal of a predetermined wavelength to travel within the core region 264a. Waveguide 264 and the reflective structure 262 are arranged to define an optical path 266 from the optical component 122 of the chip 120 to the waveguide 264 through the reflective structure 262. In some embodiments, tilt surface 222d has a predetermined angle with respect to third surface 222c in order that is sufficient to allow the reflective structure 262 to define optical path 266. In some embodiments, the predetermined angle between tilt surface 222d and third surface 222c ranges from 40 degrees to 50 degrees.
FIG. 3 is a cross-sectional view of a second example manufacture 300 having a package structure 100B mounted on a PCB substrate 212 in accordance with one or more embodiments. Components of manufacture 300 similar to those of manufacture 200 are given the same reference numbers, and detailed description thereof is omitted.
Compared with manufacture 200, substrate 222 of manufacture 300 is mounted on substrate 212 using a layer of adhesive material (not shown). Manufacture 300 includes a spacer 310 between passivation layer 150 of package structure 100B and surface 222a of substrate 222. Package structure 100B is mounted on the spacer 310, and the spacer 310 is mounted on surface 222a of substrate 222. In some embodiments, spacer 310 and package structure 100B or spacer 310 and substrate 222 has a layer of adhesive material (not shown) for holding various structures together. In some embodiments, spacer 310 is working as an adhesive layer to secure package structure 100B on substrate 222. In some embodiments, spacer 310 includes a dielectric film or a polymer film. In some embodiments, spacer 310 is formed by performing a Chemical Vapor Deposition (CVD) process or a spin-on coating process. In some embodiments, spacer 310 has a thickness usable to adjust a distance between package structure 100B and substrate 222 and/or package structure 100B and substrate 212. In some embodiments, spacer 310 has a thickness ranging from 0.1 μm to 10 μm.
Passivation layer 150 of package structure 100B has an opening 320 defined therein. Opening 320 exposes a portion of a planar portion of conductive structure 142. Manufacture 300 further includes a solder ball 330 outside substrate 222 and working as a conductive member extending across the first reference plane A and the second reference plane B and into the opening 320. Solder ball 330 is electrically coupled to the exposed portion of the planar portion of conductive structure 142 and conductive pad 214. In some embodiments, there are more than one solder ball 330 in manufacture 300 connecting corresponding conductive structures of package structure 100B and conductive pads on substrate 212.
FIG. 4 is a cross-sectional view of a third example manufacture 400 having a package structure 100C mounted on a PCB substrate 212 in accordance with one or more embodiments. Components of manufacture 400 similar to those of manufactures 200 and 300 are given the same reference numbers, and detailed description thereof is omitted.
Compared with manufacture 300, passivation layer 150 of package structure 100C has an opening 410 defined therein. Opening 410 exposes a portion of a planar portion of conductive structure 142. Manufacture 400 further includes a metallic stud 420 outside substrate 222 and working as a conductive member extending across the first reference plane A and the second reference plane B and into the opening 410. Metallic stud 420 has a first end 422 connected to the exposed portion of conductive structure 142 by using solder member 430 surrounding the first end 422 of the metallic stud 420. Metallic stud 420 also has a second end 424 connected to the conductive pad 214 of the PCB substrate 212. In some embodiments, metallic stud 420 includes copper, gold, aluminum, nickel, silver, tin, indium, or a combination thereof.
FIG. 5 is a cross-sectional view of a fourth example manufacture 500 having a package structure 100D mounted on a PCB substrate 212 in accordance with one or more embodiments. Components of manufacture 500 similar to those of manufactures 200, 300, and 400 are given the same reference numbers, and detailed description thereof is omitted.
Compared with manufactures 200, 300, and 400, substrate 222 of manufacture 500 has a surface 222a attached to passivation layer 150 of the package structure 100D. In some embodiments, substrate 222 and passivation layer 150 are secured by a layer of adhesive material (not shown) disposed therebetween. Substrate 212 of manufacture 500 is attached to molding structure 160. In some embodiments, substrate 212 and molding structure 160 are secured by a layer of adhesive material (not shown) disposed therebetween.
Passivation layer 150 of package structure 100D has an opening 510 defined therein. Opening 510 exposes a portion of a planar portion of conductive structure 142. Manufacture 500 further includes a bond wire 520 extending into the opening 510. Bond wire 520 has a first end 522 connected to the exposed portion of conductive structure 142 and a second end 524 connected to the conductive pad 214 of the PCB substrate 212. In some embodiments, bond wire 520 includes copper, gold, aluminum, silver, tin, indium, or a combination thereof.
FIG. 6 is a cross-sectional view of a fifth example manufacture 600 having a package structure 100E mounted on a PCB substrate 212 in accordance with one or more embodiments. Components of manufacture 600 similar to those of manufactures 200, 300, 400, and 500 are given the same reference numbers, and detailed description thereof is omitted.
Compared with manufacture 500, interposer 220 and reflective structure 262 and waveguide 264 mounted thereon are omitted. Instead, waveguide unit 610 is disposed on the passivation layer 150 and arranged to be optically communicative with the optical component 122 of chip 120. Waveguide unit 610 includes a waveguide 612 and a molding structure 614. Waveguide 612 includes a core region 612a and a cladding region 612b. In some embodiments, core region 612a and cladding region 612b have different reflective coefficients and are arranged to allow an optical signal of a predetermined wavelength to travel within the core region 612a. Molding structure 614 affixes waveguide 612 to a predetermined position on the package structure 100E. Molding structure 614 has a tilt surface 616 working as a reflective structure. Waveguide 614 and the reflective structure 616 are arranged to define an optical path 618 from the optical component 122 of the chip 120 to the waveguide 612 through the reflective structure 616.
FIG. 7 is a cross-sectional view of a fifth example manufacture 700 having a package structure 100F mounted on a PCB substrate 212 in accordance with one or more embodiments. Components of manufacture 700 similar to those of manufactures 200, 300, 400, 500, and 600 are given the same reference numbers, and detailed description thereof is omitted.
Manufacture 700 includes a waveguide unit 710 disposed on the passivation layer 150 and arranged to be optically communicative with the optical component 122 of chip 120. Waveguide unit 710 includes a waveguide 712 and a molding structure 714. Waveguide 712 includes a core region 712a and a cladding region 712b. In some embodiments, core region 712a and cladding region 712b have different reflective coefficients and are arranged to allow an optical signal of a predetermined wavelength to travel within the core region 712a. Molding structure 714 affixes waveguide 712 to a predetermined position on the package structure 100F. Compared with manufactures 600, waveguide 612 of manufacture 700 is arranged to have core region 712a coinciding an optical path 714 defined by the optical component 122 of the chip 120, and a reflective structure on molding structure 714 that corresponds to reflective structure 616 is omitted.
In accordance with one embodiment, a manufacture includes a package structure, a first substrate, and a conductive member of a same material. The package structure includes a chip comprising a conductive pad, a conductive structure over the chip and electrically coupled to the conductive pad, and a passivation layer over the conductive structure. The conductive structure has a planar portion substantially in parallel with an upper surface of the chip. The passivation layer has an opening defined therein, and the opening exposes a portion of the planar portion. The first substrate includes a first surface defining a first reference plane and a second surface defining a second reference plane. The conductive member extends across the first reference plane and the second reference plane and into the opening. The conductive member is electrically coupled to the exposed portion of the planar portion.
In accordance with another embodiment, a manufacture includes a package structure, a first substrate, a waveguide, and a first conductive member of a same material. The package structure includes a first chip comprising an optical component and a first conductive pad, a second chip comprising a second conductive pad, a first conductive structure over the first chip and electrically coupled to the first conductive pad, a second conductive structure over the second chip and electrically coupled to the second conductive pad, and a passivation layer over the first conductive structure and the second conductive structure. The first conductive structure has a first planar portion substantially in parallel with an upper surface of the first chip. The second conductive structure has a second planar portion substantially in parallel with an upper surface of the second chip. The passivation layer has a first opening defined therein, the first opening exposing a first exposed portion, and the first exposed portion referring to a portion of the first planar portion or a portion of the second planar portion. The first substrate includes a first surface defining a first reference plane, a second surface defining a second reference plane, a third surface between the first reference plane and the second reference plane, and a reflective surface connecting the first surface and the third surface. The waveguide and the reflective surface are arranged to define an optical path from the optical component of the first chip to the waveguide through the reflective surface. The first conductive extends across the first reference plane and the second reference plane and into the first opening. The first conductive member is electrically coupled to the first exposed portion.
In accordance with another embodiment, a manufacture includes a package structure, a waveguide over the package structure, a first substrate having a conductive pad, and a conductive member. The package structure includes a first chip having an optical component and a first conductive pad, a second chip having a second conductive pad, a first conductive structure over the first chip and electrically coupled to the first conductive pad, a second conductive structure over the second chip and electrically coupled to the second conductive pad, and a molding structure surrounding and underneath the first chip and the second chip. The first conductive structure has a first planar portion substantially in parallel with an upper surface of the first chip. The second conductive structure has a second planar portion substantially in parallel with an upper surface of the second chip. The waveguide is arranged to be optically communicative with the optical component of the first chip. The conductive member has a first end in contact with the first planar portion or the second planar portion and a second end in contact with the conductive pad of the first substrate.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.

## Claims

1. A manufacture, comprising:
a package structure, comprising:
a chip, comprising:
an optical component; and
a conductive pad;

a conductive structure over the chip and electrically coupled to the conductive pad, the conductive structure comprising a planar portion substantially in parallel with an upper surface of the chip;
a molding structure surrounding and underneath the chip; and
a passivation layer over the conductive structure, the passivation layer comprising an opening defined therein, the opening exposing a portion of the planar portion;

a first substrate, comprising:
a first surface defining a first reference plane; and
a second surface defining a second reference plane;

a conductive member of a same material extending across the first reference plane and the second reference plane and into the opening, the conductive member being electrically coupled to the exposed portion of the portion; and
an optical aperture through the passivation layer.

2. The manufacture of claim 1, wherein the conductive member comprises a solder ball, a bond wire, or a metallic stud outside the first substrate.

3. The manufacture of claim 1, further comprising:
a second substrate comprising a conductive pad, the first substrate being between the package structure and the second substrate,
wherein the conductive member is a solder ball connecting the exposed portion of the planar portion and the conductive pad of the second substrate.

4. The manufacture of claim 1, further comprising:
a second substrate comprising a conductive pad, the first substrate being between the package structure and the second substrate; and
a solder member,
wherein the first conductive member is a metallic stud having a first end connected to the first exposed portion by the solder member and a second end connected to the conductive pad of the second substrate.

5. The manufacture of claim 1, wherein
the first substrate further comprises:
a third surface between the first reference plane and the second reference plane; and
a tilt surface connecting the first surface and the third surface; and

the manufacture further comprises:
a reflective structure on the tilt surface of the first substrate; and
a waveguide on the third surface of the first substrate, the waveguide and the reflective structure being arranged to define an optical path from the optical component of the first chip to the waveguide through the reflective structure.

6. The manufacture of claim 5, wherein the optical aperture is configured to allow light to be transmitted along the optical path.

7. The manufacture of claim 1, wherein the passivation layer has a passivation layer surface coplanar with the planar portion.

8. A manufacture, comprising:
a package structure, comprising:
a first chip, comprising:
an optical component; and
a first conductive pad;

a second chip, comprising:
a second conductive pad;

a first conductive structure over the first chip and electrically coupled to the first conductive pad, the first conductive structure comprising a first planar portion substantially in parallel with an upper surface of the first chip;
a second conductive structure over the second chip and electrically coupled to the second conductive pad, the second conductive structure comprising a second planar portion substantially in parallel with an upper surface of the second chip;
a molding structure surrounding and underneath the first chip and the second chip; and
a passivation layer over the first conductive structure and the second conductive structure, the passivation layer comprising a first opening defined therein, the first opening exposing a first exposed portion, and the first exposed portion referring to a portion of the first planar portion or a portion of the second planar portion;

a first substrate, comprising:
a first surface defining a first reference plane;
a second surface defining a second reference plane;
a third surface between the first reference plane and the second reference plane; and
a reflective surface connecting the first surface and the third surface;

a waveguide on the third surface of the first substrate, the waveguide and the reflective surface being arranged to define an optical path from the optical component of the first chip to the waveguide through the reflective surface;
a first conductive member of a same material extending across the first reference plane and the second reference plane and into the first opening, the first conductive member being electrically coupled to the first exposed portion,
wherein the passivation layer has a second opening defined therein, and the second opening is aligned with the optical component along the optical path.

9. The manufacture of claim 8, wherein the first conductive member comprises a solder ball, a bond wire, or a metallic stud outside the first substrate.

10. The manufacture of claim 8, wherein the first conductive member is in direct contact with the first exposed portion.

11. The manufacture of claim 8, further comprising a spacer between the passivation layer of the package structure and the first surface of the first substrate.

12. The manufacture of claim 8, further comprising:
a second substrate comprising a conductive pad, the first substrate being between the package structure and the second substrate,
wherein the first conductive member is a solder ball connecting the first exposed portion and the conductive pad of the second substrate.

13. The manufacture of claim 8, further comprising:
a second substrate comprising a conductive pad, the first substrate being between the package structure and the second substrate; and
a solder member,
wherein the first conductive member is a metallic stud having a first end connected to the first exposed portion by the solder member and a second end connected to the conductive pad of the second substrate.

14. The manufacture of claim 8, wherein the first planar portion is physically in contact with the second planar portion.

15. The manufacture of claim 8, wherein the second opening is configured to allow light to be transmitted along the optical path.

16. A manufacture, comprising:
a package structure, comprising:
a first chip, comprising:
an optical component; and
a first conductive pad;

a second chip, comprising:
a second conductive pad;

a first conductive structure over the first chip and electrically coupled to the first conductive pad, the first conductive structure comprising a first planar portion substantially in parallel with an upper surface of the first chip;
a second conductive structure over the second chip and electrically coupled to the second conductive pad, the second conductive structure comprising a second planar portion substantially in parallel with an upper surface of the second chip;
a molding structure surrounding and underneath the first chip and the second chip; and
a passivation layer over the first conductive structure and the second conductive structure, the passivation layer having a passivation layer surface coplanar with the first planar portion or the second planar portion;

a waveguide over the package structure and arranged to be optically communicative with the optical component of the first chip;
a first substrate comprising a conductive pad; and
a conductive member of a same material having a first end in contact with the first planar portion or the second planar portion and a second end in contact with the conductive pad of the first substrate,
wherein the passivation layer has an opening defined therein, the opening is configured to facilitate the optical communication between the optical component and the waveguide.

17. The manufacture of claim 16, wherein the molding structure is mounted to the first substrate.

18. The manufacture of claim 16, further comprising a second substrate, comprising:
a first surface defining a first reference plane;
a second surface defining a second reference plane;
a third surface between the first reference plane and the second reference plane, the waveguide being mounted on the third surface; and
a reflective surface connecting the first surface and the third surface, the waveguide and the reflective surface being arranged to define an optical path from the optical component of the first chip to the waveguide through the reflective surface.

19. The manufacture of claim 16, further comprising a spacer between the package structure and the first surface of the second substrate.

20. The manufacture of claim 16, wherein the waveguide is mounted on the package structure.

21. The manufacture of claim 16, wherein the first planar portion is physically in contact with the second planar portion.