Photonic Die Package Structure With Dam-Isolated Optical Path

Solution Overview

Problem

The integration of photonic and electronic dies in devices faces challenges such as optical transmission noise and optical loss due to the fabrication process.

Innovation Solution

A package structure is developed with a die stack structure that includes a photonic die and an electronic die bonded together, featuring a conductive layer with conductive pads and a dam structure to prevent underfill from entering the optical path, thereby reducing optical transmission noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If photonic and electronic dies are integrated in devices, then full-fledged applications with optical and electrical signal processing are achieved, but optical transmission noise and optical loss occur due to fabrication process challenges

Engineering Contradiction:

Improveintegration capabilityVSAvoidoptical transmission noise

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the fabrication process into distinct stages: forming the photonic die with its optical path, bonding the electronic die to the photonic die, and then selectively filling underfill material. This segmentation allows the optical path to be protected from underfill contamination while still achieving complete die attachment, thereby resolving the contradiction between integration capability and optical transmission quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first forming the photonic die with its optical path established and protected, then bonding the electronic die before introducing underfill material. This sequence ensures that the optical path is already in place and protected from potential underfill contamination, allowing subsequent underfill application without compromising optical transmission.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If photonic and electronic dies are integrated in devices, then full-fledged applications with optical and electrical signal processing are achieved, but optical loss occurs due to fabrication process challenges

Engineering Contradiction:

Improveintegration capabilityVSAvoidoptical loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent segments the fabrication process into distinct stages: forming the photonic die with its optical path, bonding the electronic die to the photonic die, and then selectively filling underfill material. This segmentation allows the optical path to be protected from underfill contamination while still achieving complete die attachment, thereby resolving the contradiction between integration capability and optical transmission quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by first forming the photonic die with its optical path established and protected, then bonding the electronic die before introducing underfill material. This sequence ensures that the optical path is already in place and protected from potential underfill contamination, allowing subsequent underfill application without compromising optical transmission.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If underfill is used to laterally encapsulate connectors and conductive pads, then mechanical support and electrical isolation are provided, but underfill may enter the optical path causing optical transmission noise

Engineering Contradiction:

Improvemechanical supportVSAvoidoptical transmission noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the filling process by first bonding the electronic die to the photonic die, then selectively applying underfill material to laterally encapsulate connectors and conductive pads while avoiding the optical path. This segmented approach ensures mechanical support and electrical isolation are provided without underfill contamination of the optical path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by providing different treatments to different regions: underfill material is applied to regions requiring mechanical support and electrical isolation (connectors and conductive pads) while the optical path region is kept free of underfill material. This localized approach resolves the contradiction between reliability and optical transmission quality.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250069993A1Package structure with photonic die and method

Publication Date: 2025.02.27 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Provided is a package structure including a bottom die, a top die, an insulating layer, a circuit substrate, a dam structure, and an underfill. The top die is bonded on a front side of the bottom die. The insulating layer is disposed on the front side of the bottom die to laterally encapsulate a sidewall of the top die. The circuit substrate is bonded on a back side of the bottom die through a plurality of connectors. The dam structure is disposed between the circuit substrate and the back side of the bottom die, and connected to the back side of the bottom die. The underfill laterally encapsulates the connectors and the dam structure. The dam structure is electrically isolated from the circuit substrate by the underfill. A method of forming the package structure is also provided.