Stacked Die Height Reduction via Adhesive Bonding

Solution Overview

Problem

The existing semiconductor packaging methods, which involve die spacers or film on wire layers, result in increased package height and inefficiencies due to the need for extra labor and time, as well as higher production costs, when stacking multiple dies.

Innovation Solution

The use of an adhesive material between adjacent dies, combined with insulated bonding wires, allows for closer stacking without the risk of electrical shorts, eliminating the need for die spacers and reducing the overall package height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If die spacers or film on wire layers are used to prevent electrical shorts between stacked dies, then reliability is improved, but package height increases and manufacturing complexity increases

Engineering Contradiction:

Improveelectrical short preventionVSAvoidpackage height

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent removes the die spacer component entirely from the stacked die structure. Instead of using a physical spacer to prevent electrical shorts, the invention relies on the adhesive material to provide both mechanical bonding and electrical isolation, thereby eliminating the need for the spacer and reducing package height.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of the adhesive material and the die spacer into a single integrated solution. The adhesive material simultaneously provides mechanical bonding between dies and electrical isolation to prevent shorts, merging two previously separate functions into one material layer.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If die spacers are used to prevent electrical shorts, then reliability is improved, but device complexity and manufacturing labor increase

Engineering Contradiction:

Improveelectrical short preventionVSAvoidpackaging structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the functions of the adhesive material and the die spacer into a single integrated solution. The adhesive material simultaneously provides mechanical bonding between dies and electrical isolation to prevent shorts, merging two previously separate functions into one material layer.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The adhesive material is designed to perform multiple functions: mechanical bonding between dies, electrical isolation to prevent shorts, and potential stress management. This multi-functionality eliminates the need for separate spacer components and simplifies the overall packaging structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Stability of the object's composition

If die spacers with adhesive films are used to stack dies, then structural stability is improved, but manufacturing time and production cost increase

Engineering Contradiction:

Improvedie stacking stabilityVSAvoidmanufacturing time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent combines the functions of the adhesive material and the die spacer into a single integrated solution. The adhesive material simultaneously provides mechanical bonding between dies and electrical isolation to prevent shorts, merging two previously separate functions into one material layer.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The adhesive material is applied in advance to the die surface before stacking, and it is designed to provide both mechanical bonding and electrical isolation properties from the outset. This preliminary preparation eliminates the need for subsequent spacer installation steps, reducing manufacturing time.

Inventive Principle:

Principle #10Preliminary action

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

This approach reduces the gap between stacked dies, decreases the total package height, and enhances production efficiency and cost-effectiveness by eliminating the need for additional spacer materials and labor-intensive processes.

Implementation Method 1

applying an adhesive material between adjacent ones of the stacked dies

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

multiple sets of bonding wires (e.g., which are coated with an insulating material) connecting respective bonding pads

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

bonding wires (e.g., which are coated with an insulating material) connecting respective bonding pads

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS7932131B2Reduction of package height in a stacked die configuration

Publication Date: 2011.04.26 III HOLDINGS 4 LLC

AI summary

A method and structure for reducing the size of semiconductor package is disclosed. In one example embodiment, a method for stacking dies of a semiconductor package includes forming a set of insulated bonding wires between respective bonding pads of a first semiconductor integrated circuit die and a conductive layer electrically detached from the respective bonding pads, applying an adhesive material on a top surface of the first semiconductor integrated circuit die, and securing a second semiconductor integrated circuit die one the top surface of the first semiconductor integrated circuit die with the adhesive material.