Packaging optical components in a circuit package
The present disclosure relates to example implementations of optically accessible circuit packages. For example, this disclosure includes implementations for creating a circuit package with a photonic integrated circuit (PIC) connected to electrical integrated circuit (EIC) components via an organic interposer. In many implementations, the circuit package maintains optical access to a gating coupler (GC) region on the PIC via an internal cavity area in the organic interposer. In this way, a fiber array unit (FAU) or other optical connection can couple to the circuit package to communicate data from the EIC components of the circuit package and another circuit package or an external device connected to the FAU (e.g., both send and receive data with the cp) via the open access GC region.
1 . A circuit package, comprising:
an organic interposer having a top surface and a bottom surface, wherein the organic interposer includes:
an internal cavity area defining a hole in the organic interposer extending through the organic interposer from the top surface to the bottom surface; and
a dam wall that rises above the top surface of the organic interposer and surrounds the internal cavity area;
a photonic integrated circuit (PIC) positioned above the top surface of the organic interposer and attached to the organic interposer with electrical connections, wherein a photonically sensitive area of the PIC is located directly above the internal cavity area of the organic interposer; and
an underfill material between the PIC and the organic interposer, wherein the underfill material is absent in the internal cavity area.
2 . The circuit package of claim 1 , further comprising:
a removable mechanical base attached to the bottom surface of the organic interposer, wherein the hole in the internal cavity area exposes a portion of the removable mechanical base.
3 . The circuit package of claim 1 , further comprising an electronic integrated circuit component (EIC component) attached to the bottom surface of the organic interposer, wherein:
the EIC component electronically communicates with the PIC via the organic interposer; and
the EIC component is offset from the internal cavity area of the organic interposer.
4 . The circuit package of claim 3 , further comprising an electro-photonic transmitter and an electro-photonic receiver.
5 . The circuit package of claim 4 , wherein:
a first portion of the electro-photonic transmitter or the electro-photonic receiver is located within the EIC component;
a second portion of the electro-photonic transmitter or the electro-photonic receiver is located within the PIC; and
the second portion in the PIC is connected electrically to the first portion via the organic interposer.
6 . The circuit package of claim 5 , further comprising a bidirectional photonic channel in the PIC, the bidirectional photonic channel including a first unidirectional photonic link in a first direction and a second unidirectional photonic link in an opposite direction.
7 . The circuit package of claim 6 , wherein the bidirectional photonic channel connects a central processing unit (CPU) connected to the EIC component with an external device.
8 . The circuit package of claim 6 , wherein:
the first unidirectional photonic link includes a driver in the EIC component, a modulator in the PIC, and a waveguide from the modulator to a photonically sensitive region of the PIC, the photonically sensitive region of the PIC comprising grating couplers;
the photonically sensitive region of the PIC with the grating couplers is located within the internal cavity area of the organic interposer; and
the first unidirectional photonic link allows light to tangentially exit the PIC into the internal cavity area.
9 . The circuit package of claim 8 , further comprising a fiber array unit (FAU) attached to the PIC and positioned in the internal cavity area, such that light exiting the grating couplers is received by the FAU.
10 . The circuit package of claim 6 , wherein:
the second unidirectional photonic link includes a transimpedance amplifier in the EIC component, a photodetector in the PIC, and a waveguide from the photodetector to a photonically sensitive region of the PIC with grating couplers;
the photonically sensitive region of the PIC with the grating couplers is located within the internal cavity area of the organic interposer; and
the second unidirectional photonic link allows light to be received into PIC via the grating couplers.
11 . The circuit package of claim 10 , further comprising a fiber array unit (FAU) attached to the PIC via the internal cavity area, such that light from an external device attached to the FAU travels to the FAU and enters the PIC via the second unidirectional photonic link.
12 . A circuit package, comprising:
a removable mechanical base;
an organic interposer having a top surface and a bottom surface, the bottom surface attached over the removable mechanical base with a debonding material, wherein the organic interposer includes:
an internal cavity area defining a hole in the organic interposer extending through the organic interposer from the top surface to the bottom surface; and
a dam wall that rises above the top surface of the organic interposer and surrounds the internal cavity area;
a photonic integrated circuit (PIC) positioned above the top surface of the organic interposer and attached to the organic interposer with electrical connections, wherein a photonically sensitive area of the PIC is located directly above the internal cavity area of the organic interposer;
an underfill material between the PIC and the organic interposer, wherein the underfill material is absent in the internal cavity area; and
an electronic integrated circuit component (EIC component) attached to the PIC via the organic interposer, wherein the EIC component is offset from the internal cavity area of the organic interposer.
13 . The circuit package of claim 12 , wherein the removable mechanical base includes a glass carrier.
14 . The circuit package of claim 12 , wherein:
the internal cavity area is defined by an internal interposer wall from the bottom surface of the organic interposer to the top surface of the dam wall; and
the internal cavity area is void of material.
15 . The circuit package of claim 12 , wherein:
the organic interposer is generated utilizing a lithography process that builds layers of material with electrically conductive patterns over the removable mechanical base;
the lithography process deposits material on the removable mechanical base surrounding the internal cavity area of the organic interposer; and
the lithography process does not deposit material within the internal cavity area of the organic interposer on the removable mechanical base.
16 . The circuit package of claim 12 , wherein the internal cavity area is surrounded by material of the organic interposer and enables the removable mechanical base to be visible through the organic interposer.
17 . The circuit package of claim 12 , wherein the dam wall has a height length that is a same or smaller length than a width length.
18 . The circuit package of claim 12 , wherein:
the dam wall extends a height of the organic interposer surrounding the internal cavity area; and
the dam wall fully surrounds the internal cavity area.
19 . The circuit package of claim 12 , wherein the dam wall forms a perimeter wall as a rectangular shape or a round shape around the internal cavity area.
20 . The circuit package of claim 12 , wherein the PIC attaches to the organic interposer via electrical connections that cause a gap to exist between a bottom surface of the PIC and a top surface of the dam wall.
21 . The circuit package of claim 12 , wherein the PIC attaches to the organic interposer such that a gap exists between a bottom surface of the PIC and a top surface of the dam wall.
22 . The circuit package of claim 12 , wherein:
a first gap between a bottom surface of the PIC and the top surface of the organic interposer is about 20 microns; and
a second gap between the bottom surface of the PIC and a top surface of the dam wall is about 5 microns.
23 . The circuit package of claim 22 , wherein the underfill material has a viscosity value that causes the underfill material to fill the first gap and clog in the second gap without entering in the internal cavity area.
24 . The circuit package of claim 12 , wherein the underfill material includes a viscosity value that clogs the underfill material between a bottom surface of the PIC and a top surface of the dam wall.
25 . A circuit package, comprising:
an organic interposer that includes:
an internal cavity area that defines a hole in the organic interposer extending through the organic interposer from a top surface of the organic interposer to a bottom surface of the organic interposer; and
a dam wall that rises above a top surface of the organic interposer and surrounds the internal cavity area;
a photonic integrated circuit (PIC) positioned above the organic interposer and attached to the organic interposer with electrical connections such that:
a first gap exists between the PIC and a top surface of the organic interposer; and
a second gap exists between the PIC and a top surface of the dam wall; and
an underfill material between the PIC and the organic interposer, wherein the underfill material fills the first gap and a portion of the second gap without filling the internal cavity area.
26 . The circuit package of claim 25 , wherein the underfill material is epoxy.
27 . The circuit package of claim 25 , further comprising a first molding compound covering the PIC, exposed portions of the underfill material, and exposed portions of the organic interposer, wherein the underfill material clogged by the dam wall prevents the first molding compound from entering the internal cavity area.
28 . The circuit package of claim 25 , wherein:
the organic interposer is formed on a removable mechanical base; and
the removable mechanical base includes a silicon carrier, metal carrier, polymer carrier, or tape carrier.
29 . The circuit package of claim 25 , wherein the organic interposer includes one or more redistribution layers.
30 . The circuit package of claim 25 , wherein the organic interposer includes polymer dielectrics and copper, aluminum, nickel, or gold.