CN-121978807-A - Photoelectric co-packaging structure and forming method thereof

Abstract

The application discloses a photoelectric co-packaging structure and a forming method thereof, wherein the forming method comprises the steps of providing a photon chip, comprising a first surface and a second surface which are opposite, wherein the first surface is provided with a bonding pad and an optical coupling port positioned at one side of the bonding pad; the method comprises the steps of forming a protective layer covering an optical coupling port, exposing a bonding pad, forming a first welding lug on the bonding pad after the protective layer is formed, providing an initial packaging panel, wherein the initial packaging panel comprises a third surface and a fourth surface which are opposite, an electronic chip is arranged in the initial packaging panel, the third surface of the initial packaging panel is provided with a first wiring layer, the electronic chip is electrically connected with the first wiring layer, the photonic chip is reversely arranged on the first wiring layer, the first welding lug is welded with the first wiring layer, an optical interface device is arranged on one side of the photonic chip, the optical interface device is opposite to the optical coupling port, and the protective layer is removed after the optical interface device is arranged, so that the optical coupling port is exposed. Preventing damage and contamination of the optical coupling port throughout the packaging process.

Inventors

• Bi tianjiao
• LI ZONGYI
• GUO LIANGKUI
• LI WENJIE

Assignees

• 长电微电子(江阴)有限公司

Dates

Publication Date

20260505

Application Date

20251226

Claims (20)

1. 1. The method for forming the photoelectric co-packaging structure is characterized by comprising the following steps of: providing a photonic chip comprising opposing first and second surfaces, the first surface having a bonding pad and an optical coupling port located on one side of the bonding pad; Forming a protective layer covering the optical coupling port, the protective layer exposing the bonding pad; forming a first welding bump on the bonding pad after forming the protective layer; providing an initial packaging panel, wherein the initial packaging panel comprises a third surface and a fourth surface which are opposite, an electronic chip is arranged in the initial packaging panel, the third surface of the initial packaging panel is provided with a first wiring layer, and the electronic chip is electrically connected with the first wiring layer; flip-chip the photon chip on the first wiring layer, wherein the first welding lug is welded with the first wiring layer; An optical interface device is arranged on one side of the photonic chip, and the optical interface device is opposite to the optical coupling port; And after the optical interface device is installed, removing the protective layer to expose the optical coupling port.
2. 2. The method of forming a photoelectric co-package structure according to claim 1, wherein the material of the protective layer includes a thermosetting polyimide resin or a photo-curable epoxy resin.
3. 3. The method of forming a photovoltaic co-package according to claim 2, wherein the thermosetting polyimide resin or the photo-curable epoxy resin has a viscosity in the range of 50 cP to 200cP and a thickness in the range of 20 μm to 50 μm.
4. 4. The method of claim 3, wherein the process of forming the protective layer comprises an inkjet printing process or a micro-dispensing head dispensing process.
5. 5. The method of claim 4, further comprising curing the protective layer after forming the protective layer.
6. 6. The method of forming a photoelectric co-package according to claim 5, wherein when the material of the protective layer includes a thermosetting polyimide resin, the curing temperature of the curing is 170 ℃ to 190 ℃ and the curing time is 25min to 35min.
7. 7. The method of forming an optoelectronic co-package of claim 5, wherein when the material of the protective layer comprises a thermosetting polyimide resin, the curing is exposed with UV light at 365 nm.
8. 8. The method for forming a photoelectric co-packaging structure according to claim 2, wherein the protective layer is removed by a plasma photoresist removing process, the gas adopted by the plasma photoresist removing process comprises mixed gas of O 2 and CF 4 , the volume ratio of O 2 to CF 4 is in the range of 5:1-3:1, and the energy of plasma is less than or equal to 100eV.
9. 9. The method of claim 8, wherein the plasma photoresist stripping process is performed by monitoring the remaining thickness of the protective layer using an endpoint detection system to ensure photoresist stripping is stopped at the surface of the optical coupling port.
10. 10. The method of claim 8, wherein the protective layer includes a middle region and an edge region surrounding the middle region, the edge region having an annular groove therein.
11. 11. The method of claim 10, wherein the annular groove has a width of 4 μm to 6 μm.
12. 12. The method of forming a photoelectric co-package structure according to claim 2, wherein silica nanoparticles having a particle diameter of less than 100nm are added to the thermosetting polyimide resin or the photocurable epoxy resin.
13. 13. The method of forming a co-package structure of claim 1, wherein the material of the protective layer further comprises a photoresist; The protective layer can be removed by adopting photoresist stripping or laser.
14. 14. The method of claim 1, wherein the first solder bump comprises a metal bump on the pad and a solder ball on a top surface of the metal bump.
15. 15. The method of forming a photovoltaic co-package structure of claim 1, wherein the initial package panel comprises a first molding layer comprising the opposing third and fourth surfaces; the electronic chip is positioned in the first plastic sealing layer; And forming a first wiring layer on the third surface of the first plastic sealing layer.
16. 16. The method of forming a photovoltaic co-package according to claim 15, wherein a second wiring layer is formed on a fourth surface of the first molding layer, the electronic chip being further electrically connected to the second wiring layer; And forming a second solder bump on the second wiring layer, wherein the second solder bump is electrically connected with the second wiring layer.
17. 17. The method of forming a co-package structure according to claim 16, wherein a first metal pillar is further provided in the first molding layer at one side or around the electronic chip, and two ends of the first metal pillar are electrically connected to the first wiring layer and the second wiring layer, respectively; the number of the electronic chips is one or more.
18. 18. The method of forming a photovoltaic co-package of claim 1, wherein the optical coupling port is located at an edge of the photonic chip; the photonic chip is characterized by further comprising a heat dissipation cover attached to the second surface of the photonic chip, part of the heat dissipation cover extends out of the edge of the photonic chip with the optical coupling port, and the optical interface device is mounted on the bottom surface of the extending part of the heat dissipation cover.
19. 19. The method of forming an optoelectronic co-package of claim 1 or 18, wherein the optical coupling port comprises a grating coupling port or an end-face coupling port; the optical interface device comprises a fiber optic interface connector or a laser connector.
20. 20. An optoelectronic co-package structure, comprising: The optical device comprises a photonic chip, a first welding lug, a protective layer, a second welding lug, a first optical coupling lug, a second optical coupling lug, a first optical coupling lug and a second optical coupling lug, wherein the first surface and the second surface are opposite; an initial package panel comprising opposing third and fourth surfaces, the initial package panel having an electronic chip therein, the third surface of the initial package panel having a first wiring layer, the electronic chip being electrically connected to the first wiring layer; the photon chip is flip-chip mounted on the first wiring layer, and the first welding lug is welded with the first wiring layer; And the optical interface device is positioned at one side of the photonic chip and is opposite to the optical coupling port.

Description

Photoelectric co-packaging structure and forming method thereof Technical Field The present disclosure relates to semiconductor packaging, and more particularly, to a photoelectric co-packaging structure and a method for forming the same. Background The optoelectronics Co-packaging technology (Co-Packaged Optics, CPO) is an advanced optoelectronics integration technology that integrates an optical engine or photonic chip (Photonic Integrated Circuit, PIC) directly into the same package as an electronic chip (Electronic Integrated Circuit, EIC). In the photoelectric co-packaging process, the optical coupling port (or called an optical port) of the photonic chip, particularly the optical coupling port of the indium phosphide-based photonic chip, faces two major core problems: The vulnerability is that the indium phosphide material has low hardness (only 537 Kjeldahl) and large brittleness, and the working procedures of grinding, cleaning, welding and the like in the packaging process are extremely easy to generate micro cracks or cleavage and fracture due to mechanical stress, so that the photon chip is scrapped. Contamination risk-dust particles, metal debris or chemical solvents in the environment tend to intrude into the waveguide structure when the optical coupling port is exposed, resulting in increased light scattering losses (typically >1 dB), especially in non-hermetic packaging environments. Disclosure of Invention The application provides a photoelectric co-packaging structure and a forming method thereof, which are used for preventing an optical coupling port from being damaged and polluted in the whole packaging process. In order to achieve the above object, an embodiment of the present application provides a method for forming a photoelectric co-package structure, including: providing a photonic chip comprising opposing first and second surfaces, the first surface having a bonding pad and an optical coupling port located on one side of the bonding pad; Forming a protective layer covering the optical coupling port, the protective layer exposing the bonding pad; forming a first welding bump on the bonding pad after forming the protective layer; providing an initial packaging panel, wherein the initial packaging panel comprises a third surface and a fourth surface which are opposite, an electronic chip is arranged in the initial packaging panel, the third surface of the initial packaging panel is provided with a first wiring layer, and the electronic chip is electrically connected with the first wiring layer; flip-chip the photon chip on the first wiring layer, wherein the first welding lug is welded with the first wiring layer; An optical interface device is arranged on one side of the photonic chip, and the optical interface device is opposite to the optical coupling port; And after the optical interface device is installed, removing the protective layer to expose the optical coupling port. In some embodiments of the application, the material of the protective layer comprises a thermosetting polyimide resin or a photo-curable epoxy resin. In some embodiments of the application, the viscosity of the heat curable polyimide resin or the photo curable epoxy resin ranges from 50 cP to 200cP and the thickness ranges from 20 μm to 50 μm. In some embodiments of the application, the process of forming the protective layer includes an inkjet printing process or a micro-dispensing head dispensing process. In some embodiments of the application, after forming the protective layer, curing the protective layer is further included. In some embodiments of the present application, when the material of the protective layer includes a thermosetting polyimide resin, the curing temperature of the curing is 170 ℃ to 190 ℃ and the curing time is 25min to 35min. In some embodiments of the application, when the material of the protective layer comprises a thermosetting polyimide resin, the curing is exposed with 365nm UV light. In some embodiments of the present application, a plasma photoresist removing process is used for removing the protective layer, the gas used in the plasma photoresist removing process comprises a mixed gas of O 2 and CF 4, the volume ratio of O 2 to CF 4 is in the range of 5:1-3:1, and the energy of the plasma is less than or equal to 100eV. In some embodiments of the present application, the plasma photoresist stripping process is performed by monitoring the remaining thickness of the protective layer using an endpoint detection system to ensure that photoresist stripping is stopped at the surface of the optical coupling port. In some embodiments of the application, the protective layer includes a middle region and an edge region surrounding the middle region, the edge region having an annular groove therein. In some embodiments of the application, the annular groove has a width of 4 μm to 6 μm. In some embodiments of the present application, silica nanoparticles having a particle diameter of les