Dummy Die Structures for 3D Package Warpage Reduction

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Solution Overview

Problem

The semiconductor industry faces challenges in bonding integrated circuit chips directly onto substrates due to increased integration density and warpage issues, which can lead to cold joints and reliability problems in three-dimensional package structures.

Innovation Solution

Incorporating dummy die structures adjacent to active dies, particularly in scribe line regions, to reduce warpage and CTE mismatch, thereby enhancing the reliability of package structures by providing support during singulation and reducing the need for encapsulant material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If integrated circuit chips are bonded directly onto substrates to achieve three-dimensional package structures, then integration density and functionality are improved, but warpage issues occur leading to cold joints and reliability problems

Engineering Contradiction:

Improvepackage structure reliabilityVSAvoidwarpage

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

An interposer is introduced as an intermediary component between the active die and the substrate. The interposer has a first surface that bonds to the active die and a second surface that bonds to the substrate, acting as a mediator that resolves the warpage compatibility issue between the active die and substrate while enabling three-dimensional packaging.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies physical parameters by using materials with different coefficients of thermal expansion for different layers of the package structure. The interposer and substrate are designed with specific material properties that compensate for thermal expansion differences, reducing warpage during temperature cycling and manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If integration density is increased to improve functionality, then more components are integrated, but the area occupied decreases making direct bonding difficult

Engineering Contradiction:

Improveintegration densityVSAvoidbonding area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent transitions from two-dimensional planar bonding to three-dimensional vertical stacking. Multiple active dies are bonded to the interposer in different orientations and positions, utilizing vertical space to achieve high integration density while maintaining adequate bonding areas through the extended structure of the interposer.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10867965B2Package structures and methods of forming the same

Publication Date: 2020.12.15 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An embodiment is a method including bonding a first die to a first side of an interposer using first electrical connectors, bonding a second die to first side of the interposer using second electrical connectors, attaching a first dummy die to the first side of the interposer adjacent the second die, encapsulating the first die, the second die, and the first dummy die with an encapsulant, and singulating the interposer and the first dummy die to form a package structure.