Peripheral Wall Structure for Photonic Die Optical Window Protection

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Solution Overview

Problem

Encapsulation materials in semiconductor devices can flow over the optical window or grating area of photonic semiconductor dies, obstructing the transmission or reception of optical signals.

Innovation Solution

A peripheral wall structure is formed around the optical window or grating area to prevent encapsulation materials from covering the photonic circuit, using methods such as photoresist deposition and etching to create a barrier that keeps underfill and encapsulant away from the active surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encapsulation materials are applied over the photonic semiconductor die, then the photonic device is protected and encapsulated, but the encapsulation materials flow over the optical window or grating area and block optical signals

Engineering Contradiction:

Improveprotection of photonic deviceVSAvoidblocking of optical signals

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the surface around the optical window into discrete segments by forming peripheral wall structures at specific locations. These walls segment the encapsulation material flow paths, creating barriers that prevent the material from reaching the optical window while allowing other areas to be properly encapsulated.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The peripheral wall structures serve as intermediary elements between the encapsulation material and the optical window. These walls act as a mediating barrier that intercepts the flowing encapsulation material, preventing direct contact with the optical window while maintaining the overall encapsulation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a peripheral wall structure is formed to prevent encapsulation material flow, then optical signal transmission is protected, but the device structure and manufacturing process become more complex

Engineering Contradiction:

Improveblocking of optical signalsVSAvoidstructure and process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines the formation of peripheral wall structures with existing manufacturing processes such as photoresist deposition and etching. By integrating these protective structures into the standard fabrication sequence, the patent minimizes additional process steps while achieving the desired protection function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The peripheral wall structures are formed as thin film barriers using standard semiconductor fabrication techniques. These thin film walls provide effective protection against encapsulation material flow while maintaining a compact and minimally invasive structure that does not significantly increase device complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20260083025A1Semiconductor Device and Method of Making a Peripheral Wall Structure in Fan-Out Redistribution Layers

Publication Date: 2026.03.19 STATS CHIPPAC LTD

AI summary

A semiconductor device has a build-up interconnect structure. An opening is formed through the build-up interconnect structure. A peripheral wall structure is formed around the opening. A photonic semiconductor die is disposed over the build-up interconnect structure with a photonic circuit of the photonic semiconductor die aligned to the opening. A gap remains between the build-up interconnect structure and photonic semiconductor die over the peripheral wall structure. An underfill or encapsulant is deposited between the build-up interconnect structure and photonic semiconductor die.