Beveled Two-Piece Stiffener Structure for Delamination Reduction

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Solution Overview

Problem

The increasing complexity and power consumption of semiconductor dies in chip package structures lead to elevated temperatures, causing warping and delamination risks, which can result in cracks and disconnects within wiring interconnect layers and accompanying components.

Innovation Solution

A beveled stiffener structure is implemented on the package substrate, featuring a bottom portion with a tapered top surface and a top portion with a tapered bottom surface, enhancing adhesive layer application area and reducing delamination risk through optimized thermal expansion coefficients and angled surfaces to distribute shear stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional flat stiffener structure is used, then the manufacturing process is simple, but the adhesive layer area is limited and delamination risk is high under thermal stress

Engineering Contradiction:

Improvedelamination resistanceVSAvoidstiffener structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The stiffener structure incorporates beveled surfaces with specific taper angles (e.g., 45 degrees) instead of flat surfaces. This curvature/angulation increases the adhesive layer application area and allows the adhesive to better distribute and resist shear stress from thermal expansion, thereby improving delamination resistance while maintaining manufacturing feasibility through standard beveling processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention transitions from a two-dimensional flat stiffener top surface to a three-dimensional beveled surface structure. This dimensional change creates additional surface area for adhesive bonding and provides a gradient thickness profile that better accommodates thermal stress distribution, enhancing reliability without significantly complicating the manufacturing process.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If the stiffener structure is made thicker to provide more structural support, then warpage resistance improves, but manufacturing complexity and material usage increase

Engineering Contradiction:

Improvewarpage resistanceVSAvoidmanufacturing simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The stiffener structure is divided into multiple portions (e.g., first portion, second portion, third portion) with different thicknesses and bevel configurations. This segmentation allows each portion to be optimized for its specific function while maintaining overall structural integrity, providing warpage resistance without requiring uniform thickness throughout the entire stiffener structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the stiffener structure have different thicknesses and bevel angles tailored to local requirements. Areas requiring higher strength have greater thickness, while areas requiring better adhesive bonding have beveled surfaces. This local optimization provides effective warpage resistance while minimizing material usage and manufacturing complexity.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The beveled stiffener structure increases bond strength and reduces delamination risk by increasing adhesive deposition and distributing shear stress, providing enhanced structural support for fan-out packages and substrates.

Implementation Method 1

an adhesive layer attached to the tapered top surface

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

distributing shear stress

Methodology Applied

Scientific EffectShear stress distribution: Shear Stress

Data Source

PatentUS20250357371A1Two-piece type stiffener structure with beveled surface for delamination reduction and methods for forming the same

Publication Date: 2025.11.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Devices and methods for forming a chip package structure including a package substrate, a first adhesive layer attached to a top surface of the package substrate, and a beveled stiffener structure attached to the package substrate. The beveled stiffener structure may include a bottom portion including a tapered top surface, in which a bottom surface of the bottom portion is in contact with the first adhesive layer, a second adhesive layer attached to the tapered top surface, and a top portion including a tapered bottom surface, in which the tapered bottom surface is in contact with the second adhesive layer. The tapered top surface and the tapered bottom surface have a taper angle between 5 degrees and 60 degrees with respect to a top surface of the package substrate.