Multi-chip Module Assembly with Graphite Substrate and Solvent-Resistant Adhesive
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Solution Overview
Problem
Existing multi-chip module assemblies for thermal ink printing face challenges in achieving cost-effective, reliable, and simple electrical contacts, with complex and expensive manufacturing processes, and inadequate mechanical and electrical reliability, particularly when using solvent-based inks.
Innovation Solution
A multi-chip module assembly utilizing a graphite substrate with silicon chips attached directly to it, along with a Printed Wiring Board (PWB) bonded using solvent-resistant adhesive glue, which provides hermetic sealing and reduces wire elevation, and a flexible cable for electrical connections, along with a cover shield and sealing block to prevent ink penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic substrate is used to withstand elevated temperatures, then temperature resistance is improved, but manufacturing cost increases due to expensive molding and hard-tooling equipment requirements
Solution Approach 1:
The patent replaces expensive ceramic substrates with a disposable or replaceable printhead assembly that uses simpler, cheaper materials. The printhead can be replaced when worn or damaged, eliminating the need for expensive ceramic substrates that require complex molding and hard-tooling equipment for manufacturing.
Solution Approach 2:
The patent extracts the temperature resistance requirement from the substrate material itself and addresses it through the inkjet printing process parameters and printhead design, allowing the use of simpler, more cost-effective materials for the substrate while maintaining the ability to withstand elevated temperatures during operation.
2Reliability
If complex buss lines and IC packages are used, then electrical connectivity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the buss lines and IC packages into a simplified integrated structure where the electrical connections are directly formed on the printhead substrate. This integration eliminates the need for separate complex IC packages and reduces the overall device complexity while maintaining reliable electrical connectivity for the printing elements.
Solution Approach 2:
The printhead substrate is designed to perform multiple functions simultaneously: it serves as the mechanical support, the electrical connection platform, and the mounting surface for printing elements. This multi-functionality eliminates the need for separate buss lines and IC packages, reducing device complexity while maintaining electrical connectivity.
3Ease of manufacture
If double-side adhesive tape is used to bond PWB to graphite substrate, then assembly simplicity is improved, but ink penetration risk increases and solvent resistance is reduced
Solution Approach 1:
The patent uses a composite adhesive system consisting of a solvent-resistant adhesive layer between the PWB and graphite substrate, and a sealant material around the perimeter of the PWB opening. This composite approach provides both strong bonding and effective ink penetration resistance, while the solvent-resistant property ensures compatibility with solvent-based inks.
Solution Approach 2:
The patent applies different materials with different functions in different locations: a solvent-resistant adhesive is used where strong bonding and chemical resistance are needed (between PWB and substrate), while a sealant material is used at the perimeter openings where ink penetration prevention is the primary concern. This localized material selection optimizes both assembly simplicity and ink penetration resistance.
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 solution enhances the reliability and cost-effectiveness of electrical contacts, improves printing quality by reducing ink penetration risks, and maintains mechanical stability, achieving a technologically efficient and safe multi-chip module assembly.
Implementation Method 1
a Printed Wiring Board (PWB) attached to the graphite substrate by means of a solvent-resistant adhesive glue
Data Source
AI summary
A multi-chip module (MCM) assembly comprising: a graphite substrate comprising a plurality of silicon chips directly attached to the graphite substrate, and a Printed Wiring Board (PWB) attached to the graphite substrate by means of a solvent-resistant adhesive glue and provided with openings surrounding outer profiles of the silicon chips. A printing bar comprising a plurality of the MCM assemblies is also disclosed.