ESD Protection Circuit for Semiconductor Integrated Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor integrated circuit devices lack effective electrostatic discharge (ESD) protection between test pads and test circuits, making it difficult to differentiate between normal high voltage and electrostatic voltage, requiring higher trigger voltages and higher holding voltages to prevent latch-up.
Innovation Solution
Incorporating a dual voltage protection unit system with PN diodes and serially connected gate positive p-channel metal oxide semiconductor (GPPMOS) transistors, which remain turned-off during normal voltage applications and turn-on during electrostatic voltage applications, eliminating the need for snapback voltage consideration and allowing for adjustable ESD protection based on voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional ESD protection circuit is not connected between the test pad and the test circuit, then the device complexity is reduced, but the reliability of ESD protection is insufficient
Solution Approach 1:
The ESD protection circuit is designed to handle both normal high voltage test signals and electrostatic discharge events using the same circuit structure. The circuit can operate in two modes: passing normal test voltages through to the test circuit, and clamping electrostatic discharges to ground, eliminating the need for separate protection circuits for different voltage types.
Solution Approach 2:
The circuit uses voltage-dependent parameters to differentiate between normal test voltages and electrostatic discharges. By setting the clamp voltage threshold between typical test voltage levels and ESD voltage levels, the circuit automatically changes its behavior based on the input voltage magnitude, providing appropriate protection only when needed.
2Reliability
If the trigger voltage is set higher than normal high voltage and lower than electrostatic voltage, then the ESD protection reliability is improved, but the device complexity increases due to additional control requirements
Solution Approach 1:
The ESD protection circuit is designed to activate automatically based on the input voltage level without requiring external control signals or complex monitoring circuits. The intrinsic voltage-dependent characteristics of the protection devices cause them to turn on or off automatically depending on whether the input voltage exceeds the clamp threshold, simplifying the overall control architecture.
3Reliability
If the holding voltage is set higher than normal high voltage to prevent latch-up, then the reliability is improved, but the ease of operation deteriorates due to limited voltage range
Solution Approach 1:
The circuit provides different voltage handling characteristics at different operational stages. During normal test operations, the circuit maintains low impedance to pass test signals with minimal distortion. During ESD events, the circuit transitions to a high-impedance clamping state. This localized optimization allows the circuit to excel at both test signal transmission and ESD protection without compromising either function.
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 provides reliable ESD protection for both positive and negative voltages, reduces the risk of latch-up, and allows for flexible configuration of ESD protection elements according to the magnitude of electrostatic discharge, enhancing the semiconductor integrated circuit's operational safety and efficiency.
Implementation Method 1
The PN diode may be turned-off when a voltage applied from the pad may include the normal voltage having a negative level
Implementation Method 2
The GPPMOS transistors may be driven when the voltage applied from the pad may include an electrostatic voltage having a positive level to remove the electrostatic voltage
Data Source
AI summary
A semiconductor integrated circuit device may include a pad, a first voltage protection unit and a second voltage protection unit. The first voltage protection unit may be connected with the pad. The first voltage protection unit may be configured to maintain a turn-off state when a test voltage having a negative level may be applied from the pad. The second voltage protection unit may be connected between the first voltage protection unit and a ground terminal. The second voltage protection unit may be turned-on when an electrostatic voltage having a positive level may be applied from the pad. The second voltage protection unit may include a plurality of gate positive p-channel metal oxide semiconductor (GPPMOS) transistors serially connected with each other.