Hybrid Die Stacking With NCF and MUF for Alignment Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing semiconductor device assemblies face challenges such as semiconductor die alignment issues, NCF material climbing, and die level warpage, which can lead to misalignment, contamination, and mechanical stresses, affecting the integrity and reliability of the device.

Innovation Solution

A hybrid stacking method using both non-conductive film (NCF) material and mold compound (MUF) material is employed, where NCF material is used for underfilling core memory dies to prevent warpage and NCF climbing, while MUF material is used for underfilling the top semiconductor die to improve alignment accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If NCF material is used for underfilling core memory dies, then die level warpage is prevented, but NCF material climbing occurs causing misalignment and contamination

Engineering Contradiction:

Improvedie level flatnessVSAvoidNCF material climbing

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The underfilling process is segmented into two distinct stages: first applying NCF material to prevent warpage during die stacking, then applying MUF material to seal and prevent NCF climbing. This segmentation allows each material to perform its specific function without the harmful effects of the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

MUF material acts as an intermediary that seals the NCF material in place after underfilling. The MUF material prevents the NCF material from climbing up the die sidewalls, thereby eliminating the misalignment and contamination issues while preserving the warpage prevention benefits of NCF.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If traditional single-material underfilling is used, then process simplicity is maintained, but alignment accuracy and mechanical support are insufficient

Engineering Contradiction:

Improvealignment accuracyVSAvoidunderfilling process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The underfilling process is divided into two sequential steps: NCF material application for warpage control followed by MUF material application for alignment precision and sealing. This segmentation improves alignment accuracy while managing complexity through a systematic two-stage approach.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a composite underfilling system combining NCF and MUF materials with different properties. NCF provides warpage prevention characteristics while MUF provides alignment accuracy and sealing characteristics, creating a composite solution that leverages the strengths of both materials.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20250132302A1Hybrid stacking of semiconductor dies for semiconductor device assembly

Publication Date: 2025.04.24 MICRON TECHNOLOGY INC

AI summary

A semiconductor device is presented. The semiconductor device includes a lower semiconductor die, a stack of upper semiconductor dies disposed over the lower semiconductor die, a top semiconductor die disposed over the stack of upper semiconductor dies, a non-conductive film material disposed between adjacent semiconductor dies of the lower semiconductor die and the stack of upper semiconductor dies, and a mold compound material disposed between the top semiconductor die and the stack of upper semiconductor dies, and on sidewalls of the stack of upper semiconductor dies and the top semiconductor die.