# US 11,029,475 B2 · Frame lid for in-package optics

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- Number: US 11,029,475 B2
- Document ID: US11029475B2
- Status: Granted
- Kind: B2
- Application number: 16/522,531
- Filed: 2019-07-25
- Published: 2020-10-08
- Granted: 2021-06-08
- Earliest claimed: 2019-04-08
- Assignees: Cisco Technology, Inc.
- Applicants: Cisco Technology, Inc.
- Inventors: Vipulkumar K. Patel; Aparna R. Prasad; Sandeep Razdan
- Web page: https://patentgrep.com/patent/US11029475B2

## CPC

- G02B 6/4246: {Bidirectionally operating package structures}
- G02B 6/4262: {characterised by the shape of the housing (for semiconductor lasers H01S5/02208)}
- G02B 6/4242: {Mounting of the optical light guide to the lid of the package}
- G02B 6/4248: {Feed-through connections for the hermetical passage of fibres through a package wall (see provisionally also G02B6/4428)}
- G02B 6/4269: {with heat sinks or radiation fins}
- G02B 6/4271: {with thermo electric cooling}
- G02B 6/4273: {with heat insulation means to thermally decouple or restrain the heat from spreading}
- G02B 6/428: {containing printed circuit boards [PCB]}
- G02B 6/4292: {the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements}
- H10W 40/22: characterised by their shape, e.g. having conical or cylindrical projections
- H10W 40/70: Fillings or auxiliary members in containers or in encapsulations for thermal protection or control
- H10W 76/12: characterised by their shape
- H10W 76/153: having interconnections in passages through the insulating or insulated base
- H10W 76/60: Seals
- H10W 95/00: Packaging processes not covered by the other groups of this subclass
- G02B 6/4257: {having a supporting carrier or a mounting substrate or a mounting plate (G02B6/3648 takes precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure provides a frame lid assembly, which may be used in assembling an optical platform to provide isolated thermal conduction paths for various elements thereof. The frame lid assembly includes a first frame lid, including: a foot, disposed in a first plane; a roof, disposed in a second plane parallel to the first plane, the roof defining a port as a first through-hole that is perpendicular to the second plane; a wall, disposed obliquely to the first plane, separating the roof from the foot, the wall defining a slot as a second through-hole that is parallel to the first plane; a second frame lid connected to the first frame lid and thermally isolated from the first frame lid, the second frame lid including: a cap, connected to the roof via a thermal insulator; and a plug, extending perpendicularly from the cap through the port.

## Claims

### Claim 1

A platform, comprising:
a substrate;
a first Integrated Circuit (IC) mounted to the substrate at a first height relative to the substrate;
a second IC mounted to the substrate at a second height, less than the first height, relative to the substrate;
a first frame lid mounted to the substrate and defining a cavity with the substrate that encapsulates the first IC and the second IC, the first frame lid comprising:
a first roof disposed in a first plane parallel to the substrate, the first roof defining a port providing access to the second IC through the first roof;
a foot disposed in a second plane parallel to the first plane and connected to the substrate; and
a wall, connecting the first roof to the foot; and
a second frame lid mounted to the first roof via a thermal isolator and extending through the port to a third plane, parallel to the second plane to be in thermal contact with the second IC at the second height.

### Claim 2 (depends on 1)

The platform of claim 1, wherein a slot defines an opening in the wall and the foot provides access to the cavity; and the platform further comprises:
an insert, comprising: an insert foot, connected to the substrate at the opening; and an insert wall, connected to the wall at the opening, the insert wall and the wall defining the slot; and an optical fiber, connected through the slot to a photonic integrated circuit (PIC), mounted between the second IC and the substrate.

### Claim 3 (depends on 1)

The platform of claim 1, wherein the first IC is connected to the first roof within the cavity via a first Thermal Interface Material; and
wherein the second IC is connected within the cavity to the second frame lid via a second Thermal Interface Material.

### Claim 4 (depends on 3)

The platform of claim 3, further comprising:
a first heat sink connected to the first roof on a side opposite to the first Thermal Interface Material; and
a second heat sink connected to the second frame lid on a side opposite to the second Thermal Interface Material.

### Claim 5 (depends on 1)

The platform of claim 1, wherein the second frame lid is thermally isolated from the first frame lid via the thermal isolator, and wherein the thermal isolator extends into the cavity.

### Claim 6 (depends on 1)

The platform of claim 1, wherein the cavity is hermetically sealed by curing an adhesive between the foot and the substrate and the thermal isolator.

### Claim 7

A method for attaching a frame assembly to a circuit package comprising a substrate, a first Electronic Integrated Circuit (EIC) mounted to the substrate and a second EIC, the method comprising:
applying an adhesive to the substrate;
applying a first thermal interface material to a first surface of the first EIC;
applying a second thermal interface material to a second surface of the second EIC;
placing a first frame lid onto the circuit package, wherein a foot of the first frame lid contacts the adhesive, a roof of the first frame lid contacts the first thermal interface material, and the second thermal interface material is exposed by a port defined in the roof and placing the first frame lid onto the circuit package comprises:
inserting an optical fiber through a slot defined in a wall of the first frame lid; and
sliding the first frame lid along a length of the optical fiber until the foot is in contact with the adhesive;
placing a second frame lid through the port to contact the second thermal interface material, wherein the second frame lid is thermally isolated from the first frame lid; and
curing the adhesive, the first thermal interface material, and the second thermal interface material to bond the first frame lid and the second frame lid onto the circuit package and to seal the port.

### Claim 8 (depends on 7)

The method of claim 7, further comprising:
applying a thermal isolator to the port, wherein the thermal isolator separates the second frame lid from the first frame lid; and
wherein curing further comprises curing the thermal isolator to bond the second frame lid to the first frame lid.

### Claim 9 (depends on 8)

The method of claim 8, wherein the thermal isolator is applied to the roof prior to placing the first frame lid onto the circuit package.

### Claim 10 (depends on 7)

The method of claim 7, wherein placing the first frame lid onto the circuit package comprises:
placing an insert, in contact with the adhesive, between the substrate and an optical fiber in contact with a Photonic Integrated Circuit connected between the second EIC and the substrate; and
placing the first frame lid onto the adhesive, such that the optical fiber is captured between the first frame lid and the insert.

### Claim 11 (depends on 10)

The method of claim 10, wherein the insert is inserted prior to placing the first frame lid onto the adhesive.

### Claim 12 (depends on 10)

The method of claim 10, wherein curing the adhesive bonds the insert with the first frame lid.

### Claim 13 (depends on 7)

The method of claim 7, further comprising:
bonding a first heatsink to the first frame lid; and
bonding a second heatsink to the second frame lid.

### Claim 14

A method for attaching a frame assembly to a circuit package comprising a substrate, a first Electronic Integrated Circuit (EIC) mounted to the substrate at a first height relative to the substrate and a second EIC mounted to the substrate at a second height, less than the first height, relative to the substrate, the method comprising:
applying an adhesive to the substrate;
applying a first thermal interface material to a first surface of the first EIC;
applying a second thermal interface material to a second surface of the second EIC;
placing a first frame lid onto the circuit package, wherein a foot of the first frame lid contacts the adhesive in a first plane parallel to the substrate, a roof of the first frame lid contacts the first thermal interface material in a second plane parallel to the first plane, and the second thermal interface material is exposed by a port defined in the roof;
placing a second frame lid through the port to contact the second thermal interface material in a third plane parallel to the second plane, wherein the second frame lid is thermally isolated from the first frame lid; and
curing the adhesive, the first thermal interface material, and the second thermal interface material to bond the first frame lid and the second frame lid onto the circuit package and to seal the port.

### Claim 15 (depends on 14)

The method of claim 14, further comprising:
applying a thermal isolator to the port, wherein the thermal isolator separates the second frame lid from the first frame lid; and
wherein curing further comprises curing the thermal isolator to bond the second frame lid to the first frame lid.

### Claim 16 (depends on 15)

The method of claim 15, wherein the thermal isolator is applied to the roof prior to placing the first frame lid onto the circuit package.

### Claim 17 (depends on 14)

The method of claim 14, wherein placing the first frame lid onto the circuit package comprises:
placing an insert, in contact with the adhesive, between the substrate and an optical fiber in contact with a Photonic Integrated Circuit connected between the second EIC and the substrate; and
placing the first frame lid onto the adhesive, such that the optical fiber is captured between the first frame lid and the insert.

### Claim 18 (depends on 17)

The method of claim 17, wherein the insert is inserted prior to placing the first frame lid onto the adhesive.

### Claim 19 (depends on 17)

The method of claim 17, wherein curing the adhesive bonds the insert with the first frame lid.

### Claim 20 (depends on 14)

The method of claim 14, further comprising:
bonding a first heatsink to the first frame lid; and
bonding a second heatsink to the second frame lid.