SiMC Thin Film Heaters for Micro-Fluid Ejection Heads
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Solution Overview
Problem
Micro-fluid ejection devices, such as ink jet printers, require higher resistance heater materials to achieve faster fluid ejection speeds with lower driving currents and reduced sensitivity to parasitic resistance for consistent droplet ejection, necessitating improved heater materials with higher bulk and sheet resistance uniformity and a lower temperature coefficient of resistivity.
Innovation Solution
The development of thin film heaters made from silicon, metal, and carbon (SiMC) with a sheet resistance ranging from 100 to 600 ohms per square and a thickness of 100 to 800 Angstroms, which are deposited adjacent to a substrate to form a thin film resistive layer, along with defined anode and cathode conductors, to create micro-fluid ejection heads with reduced energy requirements and less sensitivity to parasitic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional heater materials are used in micro-fluid ejection heads, then the device can operate, but the ejection speed is limited and driving current requirements are high
Solution Approach 1:
The patent changes the electrical resistance parameter of the heater material from conventional low resistance to high resistance (100-600 ohms per square sheet resistance), which fundamentally alters the heating efficiency and enables faster ejection speeds with lower driving currents
Solution Approach 2:
The patent uses composite thin film heater materials comprising silicon, metal, and carbon (SiMC) that combine the properties of high resistance with good thermal conductivity and adhesion, achieving superior performance compared to conventional single-material heaters
2Reliability
If conventional heater materials with lower resistance are used, then the heater can be driven easily, but the device exhibits high sensitivity to parasitic resistance causing inconsistent droplet ejection
Solution Approach 1:
By increasing the heater resistance to 100-600 ohms per square, the patent reduces the relative impact of parasitic resistance in the circuit, thereby improving droplet ejection consistency and reducing sensitivity to resistance variations
Solution Approach 2:
The patent replaces conventional thick-film heater materials with thin-film SiMC materials that provide more stable and predictable electrical characteristics, reducing variability and improving reliability
3Area of stationary object
If lower resistance heater materials are used, then the heater can operate at lower voltages, but larger substrate area is required to accommodate the heater and drive circuitry
Solution Approach 1:
The patent increases the heater resistance parameter to 100-600 ohms per square, which reduces the current required for operation and allows for smaller drive transistor sizes, thereby reducing the overall substrate area required
Solution Approach 2:
The patent segments the heater into thin-film resistive elements that can be precisely positioned and sized, allowing for optimized layout that minimizes substrate area while maintaining heating effectiveness
4Manufacturing precision
If conventional heater materials are used, then the manufacturing process is simpler, but the sheet resistance and bulk resistance uniformity are insufficient for high-performance ejection
Solution Approach 1:
The patent employs composite SiMC thin films that inherently provide superior resistance uniformity across the substrate, with sheet resistance varying by less than ±5%, due to the synergistic properties of silicon, metal, and carbon components
Solution Approach 2:
By controlling the thin film deposition parameters and material composition ratios, the patent achieves consistent high resistance uniformity that exceeds conventional materials, while maintaining compatibility with standard semiconductor manufacturing processes
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 enables micro-fluid ejection heads with lower energy requirements, reduced sensitivity to parasitic resistance, and the ability to be driven with smaller transistors, leading to a smaller substrate area and lower costs, while maintaining high resistance and uniformity, allowing for more efficient and consistent fluid ejection.
Implementation Method 1
thin film heaters made of silicon, metal and carbon (SiMC wherein M is a metal, such as chromium)
Implementation Method 2
depositing a thin film material comprising silicon, metal and carbon (SiMC wherein M is a metal such as chromium) adjacent to a surface of a substrate to form a thin film resistive layer
Data Source
AI summary
Micro-fluid ejection devices, methods for making micro-fluid ejection heads, and micro-fluid ejection heads, including a micro-fluid ejection head. One such micro-fluid ejection head has relatively high resistance thin film heaters adjacent to a substrate. The thin film material comprises silicon, metal, and carbon (SiMC wherein M is a metal). Each thin film heater has a sheet resistance ranging from about 100 to about 600 ohms per square and a thickness ranging from about 100 to about 800 Angstroms.