Multi-Layer Via Encapsulant Structure to Prevent Delamination

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Solution Overview

Problem

Delamination occurs frequently between the encapsulating polymer and the underlying passivation layer in integrated circuit formation due to the unsuitability of polymer formation under very small vias, leading to high delamination rates.

Innovation Solution

The formation of multiple polymer layers, including a first polymer layer contacting the lower portion of the sidewall of a conductive pillar and a second polymer layer contacting the upper portion, addresses this issue by providing a stable interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single polymer layer is formed to encapsulate conductive vias, then the structure is simple and manufacturing is easier, but delamination occurs between the polymer and passivation layer

Engineering Contradiction:

Improvepolymer formation processVSAvoiddelamination resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The single polymer layer is divided into multiple polymer layers (first polymer layer and second polymer layer) with different properties. The first polymer layer provides stress buffering closer to the via, while the second polymer layer provides better adhesion to the passivation layer, eliminating delamination issues while maintaining manufacturing feasibility through sequential deposition processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the polymer structure are assigned different functional properties. The first polymer layer (closer to the via) has optimized stress buffering characteristics, while the second polymer layer (closer to the passivation layer) has optimized adhesion properties. This local differentiation resolves the contradiction by matching material properties to specific functional requirements at different locations.

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple polymer layers are formed to prevent delamination, then interface stability is improved, but device complexity increases

Engineering Contradiction:

Improvedelamination preventionVSAvoidpolymer layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The polymer system is segmented into functional layers that can be deposited sequentially using standard manufacturing processes. While the structure is divided into multiple layers, each layer serves a specific function (stress buffering vs. adhesion), and the segmentation is achieved through conventional sequential deposition techniques, minimizing the increase in device complexity while maximizing delamination prevention.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different polymer layers are assigned different local qualities (stress buffering vs. adhesion properties) to address specific interface issues. This localized functional differentiation prevents delamination at critical interfaces without requiring complex overall structural changes, as each layer is optimized for its specific location and function within the existing manufacturing framework.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250343189A1Multiple polymer layers as the encapsulant of conductive vias

Publication Date: 2025.11.06 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method includes forming a conductive pillar over and connecting to a conductive pad, dispensing a first polymer layer, wherein the first polymer layer contacts a lower portion of a sidewall of the conductive pillar, curing the first polymer layer, and dispensing a second polymer layer on the first polymer layer. The second polymer layer contacts an upper portion of the sidewall of the conductive pillar. The second polymer layer is then cured.