Semiconductor Integrated Circuit ESD Protection RC Filter
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Solution Overview
Problem
Existing semiconductor integrated circuits face challenges in effectively suppressing noise from electrostatic discharge (ESD) and electromagnetic interference (EMI) due to the inefficacy of RC filters in removing noise from pads, leading to increased costs and assembly costs from requiring additional chips.
Innovation Solution
A semiconductor integrated circuit design incorporating ESD protection elements as transistors and a capacitance element forming an RC filter on the semiconductor substrate, with standard cells arranged near the pad to reduce noise effects while maintaining low costs, utilizing N-channel and P-channel MOSFETs and resistors to optimize the RC filter's time constant and layout for improved EMS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an RC filter is formed on a separate second semiconductor chip to remove noise, then noise removal capability is improved, but parts cost and assembly cost increase due to requiring an additional chip
Solution Approach 1:
The patent combines the RC filter function with the ESD protection element into a single integrated structure on the same semiconductor chip. The capacitance element is formed using transistor structures (third and fourth transistors) that are also used for ESD protection, while the filter resistor is integrated with the protection resistor. This merging eliminates the need for a separate second chip, reducing parts cost and assembly cost while maintaining noise removal capability.
2Object-affected harmful factors
If an RC filter is used to remove noise from internal circuits, then noise removal is improved, but the filter cannot effectively remove noise directly contaminating the pad
Solution Approach 1:
The patent places the ESD protection element (including the RC filter) directly at the pad location before noise enters the internal circuit. The first and second transistors are configured as ESD protection elements with their drains connected to the pad, providing preliminary protection by diverting ESD noise to ground before it can contaminate the internal circuit. This preliminary action ensures both pad noise and internal circuit noise are effectively addressed.
3Reliability
If ESD protection elements are arranged near the pad to reduce noise effect, then EMS reliability is improved, but chip area increases
Solution Approach 1:
The patent designs the ESD protection element to perform multiple functions simultaneously: the first and second transistors provide ESD protection while the third and fourth transistors form capacitance elements for the RC filter. The protection resistor serves both as an ESD protection component and as the filter resistor. This multi-functionality allows high EMS reliability to be achieved without proportionally increasing chip area, as a single integrated structure accomplishes what would otherwise require multiple separate components.
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 design effectively reduces noise on internal circuits with improved reliability and cost-efficiency by integrating ESD protection elements within the semiconductor substrate, allowing for flexible design modifications and reduced chip area and cost.
Implementation Method 1
a capacitance element coupled to the second line so as to form an RC filter together with the filter resistor
Implementation Method 2
a first protection element including a first transistor configured as an N-channel MOSFET designed so as to withstand ESD
Data Source
AI summary
An input signal having a high level or a low level is input to a pad. A first protection element includes a first transistor configured as an N-channel MOSFET designed so as to withstand ESD. A second protection element includes a second transistor configured as a P-channel MOSFET designed so as to withstand ESD. A capacitance element is connected to a second line, and forms an RC filter together with a filter resistor. The capacitance element includes at least one from among a third transistor having the same device structure as that of the first transistor and a fourth transistor having the same device structure as that of the second transistor.