Embedded Tungsten Resistor for High TCR Temperature Sensing
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Solution Overview
Problem
Integrated circuits require temperature sensing resistors with high linear temperature coefficient of resistance, but adding high resistance metals like nickel or molybdenum increases manufacturing costs due to additional processing steps.
Innovation Solution
Forming resistors using tungsten, a material already used in integrated circuits for contact plugs, which allows for high TCR resistors without adding extra processing steps or costs, by integrating them into the existing tungsten plug formation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high resistance metals like nickel or molybdenum are added to form temperature sensing resistors, then the linear temperature coefficient of resistance is improved, but the manufacturing complexity and cost increase due to additional deposition and etching steps
Solution Approach 1:
The tungsten layer is designed to serve multiple functions: it acts as both the contact plug material and the temperature sensing resistor. By making the tungsten contact plug extend laterally to form a resistor region, the same material and processing steps produce both interconnect structures and sensing elements, eliminating the need for separate high-TCR metal deposition and etching processes
Solution Approach 2:
The invention merges the formation of contact plugs and temperature sensing resistors into a single integrated structure. The tungsten contact plug is extended laterally to create the resistor region, combining what were previously separate manufacturing operations into one unified process flow, thereby reducing manufacturing complexity while maintaining high TCR performance
2Manufacturing precision
If high resistance metals like nickel or molybdenum are added to form temperature sensing resistors, then the linear temperature coefficient of resistance is improved, but the manufacturing cost increases due to additional processing steps
Solution Approach 1:
The tungsten layer is designed to serve multiple functions: it acts as both the contact plug material and the temperature sensing resistor. By making the tungsten contact plug extend laterally to form a resistor region, the same material and processing steps produce both interconnect structures and sensing elements, eliminating the need for separate high-TCR metal deposition and etching processes
Solution Approach 2:
The tungsten contact plug structure serves its primary function as an interconnect element while simultaneously providing the temperature sensing function through its lateral extension. The existing tungsten deposition process inherently creates the resistor structure, making the system self-sufficient and eliminating the need for additional dedicated resistor formation processes
3Measurement precision
If temperature sensing resistors are formed with high TCR tolerance specifications, then the temperature measurement accuracy is improved, but the manufacturing variability increases
Solution Approach 1:
The invention changes the material parameter from conventional high-TCR metals (nickel, molybdenum) to tungsten, which has a temperature coefficient of resistance of approximately 4500 ppm/°C. This parameter change allows achieving high measurement accuracy while utilizing tungsten's well-established processing characteristics that provide better manufacturing control and reduced variability
Solution Approach 2:
The tungsten resistor is formed using the same deposition and etching processes as the surrounding interconnect structures, ensuring homogeneous material properties and consistent processing conditions across the entire device. This homogeneity reduces lot-to-lot and wafer-to-wafer variability in TCR specifications
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 enables the creation of temperature sensors with high accuracy and reduced variability, meeting specifications for TCR tolerance without increasing manufacturing complexity or expense.
Implementation Method 1
the resistance of metals commonly used in integrated circuits such as copper and aluminum has low resistance, when a temperature sensing resistor is needed, a high resistance metal such as nickel or molybdenum is added to the integrated circuit process flow to form the temperature sensing resistor
Data Source
AI summary
A high TCR tungsten resistor on a reverse biased Schottky diode. A high TCR tungsten resistor on an unsilicided polysilicon platform geometry. A high TCR tungsten resistor between two parallel polysilicon leads on remaining contact etch stop dielectric. A high TCR tungsten resistor embedded in a intermetal dielectric layer above a lower interconnect layer and below an upper interconnect layer. A method of forming a high TCR tungsten resistor on a reverse biased Schottky diode. A method of forming high TCR tungsten resistor on an unsilicided polysilicon platform geometry. A method of forming high TCR tungsten resistor between two parallel polysilicon leads on remaining contact etch stop dielectric. A method of forming high TCR tungsten resistor embedded in a inter metal dielectric layer above a lower interconnect layer and below an upper interconnect layer.