# US 2020/0400902 A1 · Interposer

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- Number: US 2020/0400902 A1
- Document ID: US20200400902A1
- Status: Published application
- Kind: A1
- Application number: 16/899,264
- Filed: 2020-06-11
- Published: 2020-12-24
- Earliest claimed: 2019-06-11
- Assignees: Rockley Photonics Limited
- Applicants: Rockley Photonics Limited
- Inventors: Vivek Raghunathan; Aaron John Zilkie
- Web page: https://patentgrep.com/patent/US20200400902A1

## CPC

- G02B 6/30: for use between fibre and thin-film device
- G02B 6/4274: {Electrical aspects (G02B6/4263 and G02B6/4265 take precedence)}
- G02B 6/423: {using guiding surfaces for the alignment}
- G02B 6/4243: {Mounting of the optical light guide into a groove (mounting optical light guides into a groove in general G02B6/3636)}
- G02B 6/4245: {Mounting of the opto-electronic elements}
- G02B 6/4257: {having a supporting carrier or a mounting substrate or a mounting plate (G02B6/3648 takes precedence)}
- G02B 6/4202: {for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles}
- H10W 70/63: Vias, e.g. via plugs
- H10W 90/722: {between stacked chips}
- H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A silicon interposer. The silicon interposer including: a silicon layer, including one or more optical waveguides each connectable to an optical fiber; an optically active component, configured to convert optical signals received from the optical fiber into electrical signals or to convert electrical signals into optical signals and provide them to the optical fiber; and one or more electrical interconnects, connected to the optically active component and connectable to a printed circuit board, a separate die, a separate substrate, or a wafer level package.

## Claims

### Claim 1

A silicon interposer, including:
a silicon layer, including one or more optical waveguides each connectable to an optical fiber;
an optically active component, configured to convert optical signals received from the optical fiber into electrical signals or to convert electrical signals into optical signals and provide them to the optical fiber; and
one or more electrical interconnects, connected to the optically active component and connectable to a printed circuit board, a separate die, a separate substrate, or a wafer level package.

### Claim 2 (depends on 1)

The silicon interposer of claim 1, wherein the optically active component is a III-V semiconductor based optically active component.

### Claim 3 (depends on 1)

The silicon interposer of claim 1, wherein the optically active component includes a photodiode, configured to convert optical signals received from the optical fiber into electrical signals which are provided to the one or more electrical interconnects.

### Claim 4 (depends on 1)

The silicon interposer of claim 1, wherein the optically active component includes a light source and a modulator, configured to convert an electrical signal received from a first electrical interconnect of the one or more electrical interconnects to an optical signal providable to the optical fiber.

### Claim 5 (depends on 1)

The silicon interposer of claim 1, wherein the one or more electrical interconnects include one or more solder bumps or copper pillars with solder caps.

### Claim 6 (depends on 1)

The silicon interposer of claim 1, wherein the one or more electrical interconnects include one or more pins in a pin grid array.

### Claim 7 (depends on 1)

The silicon interposer of claim 1, wherein the silicon interposer includes a metal redistribution layer, which forms a part of an electrical connection between the optically active component and the one or more electrical interconnects.

### Claim 8 (depends on 1)

The silicon interposer of claim 1, wherein the silicon interposer includes one or more passivation layers located between the one or more optical waveguides and the one or more electrical interconnects.

### Claim 9 (depends on 1)

The silicon interposer of claim 1, wherein the optical fiber is attached to the respective optical waveguide using a reflow compatible joint.

### Claim 10 (depends on 1)

The silicon interposer of claim 1, wherein the optical fiber is secured to the respective optical waveguide using a cap.

### Claim 11 (depends on 1)

The silicon interposer of claim 1, wherein the silicon interposer is provided as a double-silicon-on-insulator, wafer (DSOI wafer), the one or more optical waveguides being formed in a silicon layer of the DSOI wafer.

### Claim 12 (depends on 11)

The silicon interposer of claim 11, wherein the optically active component is provided on the same silicon layer of the DSOI wafer as the one or more optical waveguides.

### Claim 13 (depends on 1)

The silicon interposer of claim 1, wherein the silicon interposer includes a mode converter located between each optical fiber and the respective optical waveguide.

### Claim 14

A method of manufacturing a silicon interposer, including the steps of:
providing a double silicon-on-insulator wafer, (DSOI wafer) in which one or more optical waveguides are fabricated;
forming an interface at each of the one or more optical waveguides suitable for connection to an optical fiber;
providing an optically active component, configured to convert optical signals received from the optical fiber into electrical signals or to convert electrical signals into optical signals and provide them to the optical fiber; and
providing one or more electrical interconnects connected to the optically active component and connectable to a printed circuit board, a separate die, a separate substrate, or a wafer level package.

### Claim 15 (depends on 14)

The method of claim 14, wherein forming the interface includes forming one or more V-groove interfaces for connection to the optical fiber.

### Claim 16 (depends on 14)

The method of claim 14, wherein providing the optically active component includes providing a wafer including the optically active component, and bonding or transfer printing the optically active component onto the DSOI wafer.

### Claim 17 (depends on 14)

The method of claim 14, including a step, between providing the optically active component and the one or more electrical interconnects, of providing a passivation layer.

### Claim 18 (depends on 14)

The method of claim 14, including a step, between providing the optically active component and the one or more electrical interconnects, of providing a metal redistribution layer which forms a part of an electrical connection between the optically active component and the one or more electrical interconnects.

### Claim 19 (depends on 18)

The method of claim 18, including a step, after providing the metal redistribution layer, of providing a second passivation layer.

### Claim 20 (depends on 14)

The method of claim 14, including a step, after providing the optically active component, of defining one or more under-bump metallization regions, suitable for use with the one or more electrical interconnects.

### Claim 21 (depends on 14)

The method of claim 14, wherein the one or more electrical interconnects are providing through a solder ball drop process, a copper pillar bumping process, or through solder printing.

### Claim 22 (depends on 14)

The method of claim 14, wherein the one or more electrical interconnects are provided through attachment of one or more pins of a pin grid array to the silicon interposer.

### Claim 23 (depends on 14)

The method of claim 14, including a step of attaching an optical fiber to the interface, and securing it in place.

### Claim 24 (depends on 23)

The method of claim 23, wherein securing the optical fiber is performed by providing a reflow compatible joint between a cap and the optical fiber.