Printed Conductive Connectors for Micro-Fluid Ejection Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micro-fluid ejection devices face challenges with larger contact pads and gaps between conductive leads/wires and adhesive/underfill materials, leading to corrosion and inefficiencies in interconnections between semiconductor substrates and circuit devices.
Innovation Solution
The method involves printing elongate strips of electrically conductive material to connect contact pads on semiconductor substrates with those on electrical trace circuits, using a conductive fluid that contains a liquid component and conductive particles, allowing for precise interconnections across uneven surfaces and reducing the need for larger contact pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional bonding methods (hot bar gang soldering or TAB) are used to connect flexible circuits to substrate contact pads, then electrical interconnection is achieved, but contact pads must be large and spaced far apart, consuming valuable substrate surface area
Solution Approach 1:
The patent replaces conventional mechanical bonding methods (hot bar gang soldering, TAB) with a printed conductive material system. Conductive ink or paste is deposited through a print head to create conductive traces that electrically connect contact pads, eliminating the need for physical bonding processes and associated large contact pad requirements
Solution Approach 2:
The invention changes the physical state and application method of conductive material from solid wire/foil bonding to liquid/conductive paste deposition. This allows precise control of conductor geometry, enabling smaller contact pads and more flexible routing patterns that optimize substrate area utilization
2Reliability
If conductive leads or wires are bonded to contact pads and underfill material is applied to prevent corrosion, then fluid protection is improved, but gaps between leads/wires and underfill material allow fluid to enter and corrode the interconnections
Solution Approach 1:
The patent replaces discrete wire/lead interconnections with printed conductive traces that are deposited directly onto the substrate surface. This creates a planar, continuous conductive path that can be fully encapsulated by underfill material without gaps, eliminating the corrosion vulnerability of protruding wire bonds
Solution Approach 2:
The invention merges the conductor and substrate into a more integrated structure where conductive traces are deposited directly on the substrate surface. This integration allows the underfill material to completely surround and protect the conductive path, combining electrical connection and environmental protection into a unified sealed structure
3Reliability
If larger contact pads are used to enable conventional bonding connections, then interconnection reliability is improved, but substrate surface area is consumed
Solution Approach 1:
The invention changes the application method of conductive material from pre-formed wire/foil to printed deposition, enabling precise control of conductor dimensions. This allows optimization of contact pad size to minimum required dimensions while maintaining reliable electrical connection, maximizing substrate area for functional elements
Solution Approach 2:
By replacing mechanical bonding systems with printed conductive traces, the patent eliminates the geometric constraints of wire bonding and TAB processes. The printed traces can be deposited in optimized patterns that minimize contact pad size while ensuring adequate electrical connection and mechanical adhesion
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 eliminates gaps between connectors and underlying surfaces, enables connections to smaller contact pads, and provides more precise interconnections compared to conventional methods, reducing corrosive effects and substrate surface area requirements.
Implementation Method 1
printing an elongate strip of an electrically conductive fluid to electrically interconnect a first contact pad on a semiconductor substrate containing fluid ejection actuator devices with a second contact pad on an electrical trace circuit
Implementation Method 2
removing the liquid component from the conductive particle component to provide a solid elongate strip of conductive material interconnecting the first contact pad and the second contact pad
Data Source
AI summary
Methods of connecting a circuit device to a semiconductor substrate and micro-fluid ejection devices made by the methods. One method includes printing an elongate strip of an electrically conductive fluid to electrically interconnect a first contact pad on a semiconductor substrate containing fluid ejection actuator devices with a second contact pad on an electrical trace circuit, wherein the electrical trace circuit is disposed adjacent to and spaced-apart from the semiconductor substrate. The electrically conductive fluid contains a liquid component and a conductive particle component. The liquid component is removed from the conductive particle component to provide a solid elongate strip of conductive material interconnecting the first contact pad and the second contact pad.