Integrated Resistor Tub Structure for High-Current Low Sheet Resistance
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Solution Overview
Problem
Integrated metal film resistors lack high current capability and low sheet resistance, limiting their application in current sensing and other circuits.
Innovation Solution
An integrated resistor design featuring a resistor tub formed from conformal metal with a dielectric liner and a resistive element of increased thickness, allowing for higher current carrying capability and lower sheet resistance, formed concurrently with other IC structures without additional mask operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If integrated thin film resistors are used to reduce cost and form factor, then manufacturing cost and device size are improved, but current capability and sheet resistance performance deteriorate
Solution Approach 1:
The patent changes the thickness parameter of the resistive element from conventional thin film (typically <0.1 μm) to thick film (at least 0.5 μm). This parameter change enables the integrated resistor to achieve low sheet resistance (below 10 Ω/square) and high current capability (at least 1 A) while maintaining the cost and size advantages of integrated fabrication processes
Solution Approach 2:
The patent transitions from planar thin film resistance to three-dimensional thick film resistance by increasing the vertical dimension of the resistive element. This dimensional change allows current to flow through a larger cross-sectional area, thereby increasing current capability while maintaining compatibility with integrated circuit fabrication
2Area of moving object
If conventional thin film resistive elements are used in integrated circuits, then integration density is improved, but current carrying capability and low sheet resistance deteriorate
Solution Approach 1:
The patent modifies the thickness parameter of the resistive element to at least 0.5 μm, enabling it to carry high current (at least 1 A) and achieve low sheet resistance (below 10 Ω/square) while maintaining compact integrated circuit footprint through efficient space utilization
3Reliability
If thicker resistive elements are used to increase current capability, then current carrying capability and low sheet resistance are improved, but manufacturing process complexity may worsen
Solution Approach 1:
The patent combines the formation of the thick resistive element with standard integrated circuit fabrication steps. The resistive element is formed as part of the interconnect structure using deposition and planarization processes that are already present in CMOS manufacturing, avoiding the need for separate specialized processing stages
Solution Approach 2:
The thick resistive element structure serves multiple functions: it provides high current capability for power distribution, low sheet resistance for signal routing, and thermal management benefits. This multi-functional design allows a single structure to address multiple circuit requirements without increasing overall device complexity
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 integrated resistor achieves high current capability above 1 A and low sheet resistance below 10 Ω/square, enhancing its performance in applications like current sensing and bridge circuits.
Implementation Method 1
a resistor tub formed from a conformal metal
Implementation Method 2
the dielectric liner electrically insulates the resistive element from the resistor tub
Data Source
AI summary
An integrated resistor includes a resistor tub, a resistive element, and a dielectric liner. The resistor tub is formed from a conformal metal, and includes a laterally-extending tub base and vertically-extending tub sidewalls extending upwardly from the laterally-extending tub base, wherein the laterally-extending tub base and vertically-extending tub sidewalls define in a resistor tub interior opening. The dielectric liner is formed in the resistor tub interior opening. The resistive element is formed over the dielectric liner in the resistor tub interior opening, and includes a pair of resistor heads connected by a laterally-extending resistor body. The dielectric liner electrically insulates the resistive element from the resistor tub.