Polysilicon ESD Diode Layout for Compact Semiconductor Dies
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Solution Overview
Problem
Existing semiconductor devices face limitations in effectively protecting against electrostatic discharge (ESD) due to restricted space for ESD protection diodes, which can lead to current crowding and increased electric fields, potentially damaging the diodes during ESD events.
Innovation Solution
A semiconductor die design featuring a polysilicon ESD protection diode with two separate sections electrically coupled in parallel between the gate and source pads, positioned laterally and vertically above a shielding region, avoiding concave sections at corners to reduce current crowding and electric field concentrations, while convex extensions increase the diode's width without occupying additional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ESD protection diode is made larger to increase protection capability, then the HBM protection rating is improved, but the device area increases
Solution Approach 1:
The ESD protection diode is positioned vertically above the shielding region, utilizing the vertical dimension rather than expanding laterally. This allows the diode to achieve enhanced protection capability through increased width in the vertical plane while maintaining a compact lateral footprint, effectively resolving the contradiction between protection rating and device area.
2Area of stationary object
If the ESD protection diode is placed in limited space, then the device size is reduced, but current crowding and electric field concentration increase causing diode damage
Solution Approach 1:
By positioning the ESD protection diode vertically above the shielding region and extending it in the vertical direction, the design achieves sufficient current distribution area without lateral expansion. This vertical arrangement prevents current crowding and electric field concentration while maintaining a compact device footprint.
Solution Approach 2:
The shielding region acts as an intermediary structure between the ESD protection diode and the underlying circuitry. It provides electrical shielding and supports the vertically positioned diode, enabling the diode to function effectively in a compact space without suffering from current crowding issues.
3Ease of manufacture
If conventional ESD protection structures are used, then the implementation is simple, but the protection effectiveness is insufficient
Solution Approach 1:
The invention maintains implementation simplicity by using standard semiconductor fabrication processes while achieving enhanced protection effectiveness through the vertical positioning of the ESD protection diode above the shielding region. This dimensional approach provides superior protection without complicating the manufacturing process.
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 enhances the ESD protection capability of semiconductor devices by reducing the risk of diode damage during ESD events, maintaining a compact device size, and increasing the Human Body Model (HBM) protection rating without expanding the active device area.
Implementation Method 1
semiconductor devices may be subjected to electrostatic discharge (ESD) events
Implementation Method 2
The polysilicon ESD protection diode is arranged laterally between the gate pad and the source pad and vertically above at least a portion of the shielding region
Implementation Method 3
a shielding region laterally surrounding the cell field, the shielding region comprising a non-depletable doped region
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
In an embodiment, a semiconductor die comprises a transistor device that comprises a cell field and an edge termination region, a source pad arranged on the cell field, a gate pad laterally arranged laterally adjacent the cell field and in the edge termination region, a shielding region laterally surrounding the cell field, the shielding region comprising a non-depletable doped. The polysilicon ESD protection diode is arranged laterally between the gate pad and the source pad and vertically above at least a portion of the shielding region and comprises at least two separate sections that are electrically coupled in parallel between the gate pad and the source pad. The sections are laterally spaced apart by a gap situated at a corner of the gate pad.