Sinterable Die Attach Films for Low-Pressure Lamination

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Solution Overview

Problem

Conventional sintering films in the die attach industry face challenges with high metal content leading to surface dryness, hindering lamination and bonding, and require high temperatures and pressures that exceed the capabilities of standard semiconductor equipment, making them unsuitable for lead-free materials and high circuit density semiconductor devices.

Innovation Solution

Development of sinterable films and pastes with compositions including thermosetting or thermoplastic resin components, such as epoxy resins, acrylic polymers, and conductive fillers like silver, which enable low-temperature and low-pressure lamination, maintaining wetting ability and achieving proper sintering morphology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sintering films with high metal content are used, then electrical and thermal conductivity is improved, but surface dryness occurs which hinders lamination and bonding performance

Engineering Contradiction:
Improveelectrical and thermal conductivityVSAvoidlamination and bonding performance
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

A binder system comprising thermoplastic resin and thermosetting resin is introduced as an intermediary between the metal particles and the lamination process. The thermoplastic resin provides initial adhesion and the thermosetting resin cures to form a strong bond, enabling effective lamination and bonding while maintaining the high metal content (60-95 wt%) needed for electrical and thermal conductivity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sintering film is formulated as a composite material system containing metal particles (60-95 wt%), thermoplastic resin (1-30 wt%), and thermosetting resin (1-30 wt%). This composite structure allows the metal particles to provide conductivity while the resin matrix provides binding and lamination capabilities, resolving the contradiction between high metal content and lamination performance

Inventive Principle:
Principle #40Composite materials

2Strength

If high temperatures and pressures are applied for lamination and bonding, then bonding strength is improved, but the process exceeds the capacities of commonly used semiconductor equipment

Engineering Contradiction:
Improvebonding strengthVSAvoidequipment capacity requirements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The binder system is designed to enable lamination and bonding at reduced temperatures (e.g., 100-200°C for lamination, 200-400°C for bonding) and pressures compared to conventional sintering films. The thermoplastic resin softens at lower temperatures to facilitate lamination, and the thermosetting resin cures to provide strong bonding, eliminating the need for high-temperature high-pressure equipment

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional sintering films are used, then lead-free compliance is achieved, but the high metal content causes surface dryness that prevents proper lamination

Engineering Contradiction:
Improvelead-free complianceVSAvoidlamination processability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The binder system acts as an intermediary that bridges the high metal content formulation and the lamination process. The thermoplastic and thermosetting resins provide the necessary surface properties and adhesion mechanisms to enable proper lamination of lead-free compliant sintering films with 60-95 wt% metal content

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The film is formulated as a composite with metal particles (60-95 wt%), thermoplastic resin (1-30 wt%), and thermosetting resin (1-30 wt%). This composite structure maintains lead-free compliance while the resin components prevent surface dryness and enable lamination processability

Inventive Principle:
Principle #40Composite materials

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 sinterable films and pastes allow for efficient lamination and bonding at reduced temperatures and pressures, ensuring high electrical and thermal conductivity while adhering to lead-free regulations, suitable for advanced semiconductor applications.

Implementation Method 1

a) A conductive pattern is formed on a green body of a ceramic component by printing a sinterable paste thereon; b) The green body with the conductive pattern is sintered to sinter the conductive paste

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3294799B1Sinterable films and pastes and methods for the use thereof
Publication Date: 2024.09.04 HENKEL KGAA
  • EP3294799B1 patent drawingFigure 1A~1B
  • EP3294799B1 patent drawingFigure 2A~2B
  • EP3294799B1 patent drawingFigure 3A~3B

AI summary

Provided herein are sinterable films and pastes as conductive die attach materials having advantageous properties for use in die semiconductor packages. Also provided are formulations useful for the preparation of such films and pastes, as well as methods for making such formulations. In additional aspects of the present invention, there are provided conductive networks prepared from compositions according to the present invention. In certain aspects, the invention relates to articles comprising such sintering films and pastes adhered to a suitable substrate therefor.