ESD Protection Using NPN Transistors and Deep Trench Capacitors
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Solution Overview
Problem
Existing ESD protection mechanisms in semiconductor technology, such as RC triggered solutions, consume a large die area and fail to meet the increasing requirements of advanced submicron semiconductor processes.
Innovation Solution
An ESD protection device formed by two NPN transistors and a plurality of deep trench capacitors, which provides a discharge path and reduces the contact resistance, allowing for effective ESD current conduction without increasing die area, utilizing parasitic transistors and capacitors to form an efficient ESD protection structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RC triggered ESD protection solution is used, then ESD protection function is provided, but die area consumption increases
Solution Approach 1:
The patent combines multiple ESD protection mechanisms (SCR and PMOS transistor) into a single integrated structure where the PMOS transistor gate is directly coupled to the SCR anode, creating a compact hybrid protection device that provides both snapback and trigger functions without requiring separate RC circuits
Solution Approach 2:
The ESD protection device performs multiple functions simultaneously: the SCR provides snapback protection for high voltage events, while the PMOS transistor provides trigger protection for lower voltage events, making the single structure universally protective against different ESD stress conditions without requiring multiple separate protection circuits
2Area of stationary object
If advanced submicron semiconductor processes are used, then physical size of semiconductor chip is reduced, but existing ESD protection mechanisms become inadequate
Solution Approach 1:
The patent adapts the ESD protection structure to submicron processes by modifying device parameters such as reducing the size of the PMOS transistor and SCR components, adjusting doping concentrations, and optimizing the coupling mechanism between components to ensure proper operation at smaller feature sizes while maintaining protection effectiveness
3Reliability
If contact resistance is not reduced, then ESD current conduction is impaired, but structure complexity increases
Solution Approach 1:
The patent implements self-service by forming the low contact resistance n-type region directly within the p-type substrate during the fabrication process, allowing the structure to provide its own contact resistance reduction function without requiring additional external components or complex interconnect structures
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 solution effectively reduces ESD failures by providing a minimal die area occupation and reliable ESD protection, stabilizing voltage and preventing semiconductor device damage through efficient current discharge paths.
Implementation Method 1
Electrostatic Discharge (ESD) is a rapid discharge that flows between two objects due to the built-up of static charge. ESD may destroy semiconductor devices because the rapid discharge can produce a relatively large current.
Implementation Method 2
If an electrostatic transient occurs across the drain region and the source region, the NPN transistor is turned on and the ESD current flows from the drain region to the source region
Implementation Method 3
An ESD protection device formed by two NPN transistors and a plurality of deep trench capacitors, which provides a discharge path and reduces the contact resistance
Data Source
AI summary
An electrostatic discharge (ESD) protection structure comprises a first NPN transistor and a second NPN transistor connected in parallel. The bases of the first NPN transistor and the second NPN transistor are coupled together and further coupled to a first voltage potential and a second voltage potential through two deep trench capacitors respectively. The ESD protection structure further comprises a third deep trench capacitor and a fourth deep trench capacitor coupled between the first voltage potential and the second voltage potential.