# US 12,181,722 B2 · Structures and process flow for integrated photonic-electric ic package by using polymer waveguide

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- Number: US 12,181,722 B2
- Document ID: US12181722B2
- Status: Granted
- Kind: B2
- Application number: 18/232,317
- Filed: 2023-08-09
- Published: 2023-11-30
- Granted: 2024-12-31
- Earliest claimed: 2021-05-14
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Yu-Hao Chen; Hui-Yu Lee; Chung-Ming Weng; Jui-Feng Kuan; Chien-Te Wu
- Web page: https://patentgrep.com/patent/US12181722B2

## CPC

- G02B 6/4214: {the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device (G02B6/4246 takes precedence)}
- H10P 72/74: {using temporarily an auxiliary support}
- G02B 6/1221: {made from organic materials}
- G02B 6/4201: {Packages, e.g. shape, construction, internal or external details}
- G02B 6/4204: {the coupling comprising intermediate optical elements, e.g. lenses, holograms (encapsulated active devices H01S5/02208)}
- H10W 90/00: Package configurations
- H10P 72/7424: {used as a support during the manufacture of self-supporting substrates}
- H10P 72/743: {used as a support during manufacture of interconnect decals or build up layers}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Disclosed are apparatus and methods for a silicon photonic (SiPh) structure comprising the integration of an electrical integrated circuit (EIC); a photonic integrated circuit (PIC) disposed on top of the EIC; two or more polymer waveguides (PWGs) disposed on top of the PIC and formed by layers of cladding polymer and core polymer; and an integration fan-out redistribution (InFO RDL) layer disposed on top of the two or more PWGs. The operation of PWGs is based on the refractive indexes of the cladding and core polymers. Inter-layer optical signals coupling is provided by edge-coupling, reflective prisms and grating coupling. A wafer-level system implements a SiPh structure die and provides inter-die signal optical interconnections among the PWGs.

## Claims

### Claim 1

A method for a fabricating a SiPh structure using polymer waveguides, the method comprising:
attaching a photonic integrated circuit (PIC) on top of an electrical integrated circuit (EIC) with hybrid die bonding to form a photonic/electric integrated circuit (IC) package;
forming a polymer waveguide (PWG) bridging layer comprising at least one PWG and positioning the PWG bridging layer on top of the PIC;
positioning at least one applications specific integrated circuit (ASIC) within the photonic/electric IC package;
forming an integrated fan-out redistribution layer (InFO RDL) on top of the PWG bridging layer; and
forming at least one optical lens adjacent to the InFO RDL layer and configured to direct a light signal through the InFO RDL layer.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
forming vias within the PWG bridging layer; and
forming through-silicon vias (TSVs) in the PIC to allow a conductive connection between layers of SiPh structure.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
forming supportive fillings beneath the EIC; and
attaching the supportive filling and the at least one ASIC to a carrier.

### Claim 4 (depends on 1)

The method of claim 1, wherein the at least one PWG comprises a core layer comprising a first polymer and at least two cladding layers comprising a second polymer that surrounds the core layer.

### Claim 5 (depends on 1)

The method of claim 1 further comprising:
forming a SiPh grating coupler between the PIC and the at least one PWG.

### Claim 6 (depends on 5)

The method of claim 5, wherein the SiPh grating coupler comprises first and second grating structures, respectively, wherein light from the at least one optical lens is received by the first grating structure, which changes a direction of the light so that the light is collected by the second grating structure so as to direct light between the PIC and the at least one PWG.

### Claim 7 (depends on 1)

The method of claim 1, wherein a polymer used in the at least one PWG is designed for a refractive index range of 1.3 to 2.0.

### Claim 8 (depends on 1)

The method of claim 1, wherein a polymer used in the first and second PWGs is designed for a refractive index range of 1.3 to 2.0.

### Claim 9

A method of making a silicon photonic (SiPh) structure comprising:
providing an electrical integrated circuit (EIC);
providing a photonic integrated circuit (PIC) on top of the EIC;
forming at least one polymer waveguide (PWG) disposed on top of the PIC and forming a polymer bridging layer, wherein the at least one PWG comprises a core layer comprising a first polymer and at least two cladding layers comprising a second polymer that surrounds the core layer;
forming an integration fan-out redistribution (InFO RDL) layer disposed on top of the at least one PWG;
forming at least one optical lens adjacent to the InFO RDL layer and configured to direct a light signal through the InFO RDL layer; and
forming a SiPh grating coupler between the PIC and the at least one PWG, wherein the SiPh grating coupler comprises first and second grating structures, respectively, wherein light from the at least one optical lens is received by the first grating structure, which changes a direction of the light so that the light is collected by the second grating structure so as to direct light between the PIC and the at least one PWG.

### Claim 10 (depends on 9)

The method of claim 9, wherein a polymer used in the at least one PWG is designed for a refractive index range of 1.3 to 2.0.

### Claim 11 (depends on 9)

The method of claim 9, wherein at least one of the first polymer and the second polymer is modified to change their respective refractive indexes.

### Claim 12 (depends on 9)

The method of claim 9, wherein layers of the first polymer and the second polymer are patterned by lithography to facilitate implementation of waveguide patterns, via holes and concave/bump topology.

### Claim 13 (depends on 9)

The method of claim 9, further comprising forming through PWG vias between PWG layers to provide inter-layer electrical connections.

### Claim 14 (depends on 9)

The method of claim 9, wherein the at least one PWG comprises a first PWG and a second PWG formed above the first PWG, and the SiPH structure further comprises an inter-layer optical signal coupler, operable for transferring a light signal from a first core layer of the first PWG to second core layer of the second PWG through at least one cladding layer.

### Claim 15 (depends on 14)

The method of claim 14, wherein the inter-layer optical signal coupler comprises a grating coupler having a first grating structure formed in the one core layer and a second grating structure formed in the another core layer.

### Claim 16 (depends on 14)

The method of claim 14, wherein the inter-layer optical signal coupler is fabricated with concave/bump topology that is formed on surfaces of the layers of the first polymer and the second polymer.

### Claim 17

A method of making silicon photonic (SiPh) structure comprising:
providing an electrical integrated circuit (EIC);
placing a photonic integrated circuit (PIC) on top of the EIC;
forming a first polymer waveguide (PWG) on top of the PIC, wherein the first PWG comprises a first core layer comprising a first polymer and at least two cladding layers comprising a second polymer that surrounds the core layer;
forming a second PWG disposed on top of the first PWG, wherein the second PWG comprises a second core layer comprising a third polymer and at least two second cladding layers comprising a fourth polymer that surrounds the second core layer;
forming at least one optical lens adjacent to the first and second PWGs, wherein the at least one optical lens is configured to direct a light signal from an external source through the first and second PWGs; and
forming a SiPh grating coupler between the PIC and the first PWG, the SiPh grating coupler comprising first and second grating structures, respectively, wherein light from the at least one optical lens is received by the first grating structure, which changes a direction of the light so that the light is collected by the second grating structure so as to direct light between the PIC and the first PWG.

### Claim 18 (depends on 17)

The method of claim 17, further comprising forming an integration fan-out redistribution (InFO RDL) layer on top of the second PWG.

### Claim 19 (depends on 18)

The method of claim 18, wherein the external source comprises a fiber, and wherein the fiber is coupled to the at least one optical lens which directs the light from the fiber through the InFO RDL layer, and the first and second PWGs to the SiPh grating coupler.

### Claim 20 (depends on 17)

The method of claim 17, wherein the at least one optical lens is formed with polymer and silicon.