Semiconductor Pad Structure to Limit Plasma Antenna Damage
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Solution Overview
Problem
Conventional semiconductor devices suffer from plasma damage due to the 'antenna effect' caused by metal layers and via units, which can lead to damage of the gate of metal oxide semiconductor (MOS) devices.
Innovation Solution
A semiconductor device with a pad structure comprising a main pad portion, a sub-pad portion, a pad bonding unit, and a bridge pad unit, where the main and sub-pad portions are connected only via these units, reducing direct connection and thus minimizing plasma damage. The pad bonding and bridge pad units are formed using electrodeposition, and the sub-pad portion is designed to encircle or have a dot structure with a lower surface area ratio compared to the gate, reducing plasma exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal layers and via units are directly connected to form pad structures, then electrical connectivity is improved, but plasma damage effect increases
Solution Approach 1:
The pad structure is divided into multiple separate pad portions (first pad portion, second pad portion, third pad portion) that are not directly connected. Each pad portion is independently formed in separate metal layers, preventing the formation of continuous antenna structures that cause plasma damage while maintaining electrical connectivity through indirect paths.
Solution Approach 2:
A bridge pad unit is introduced as an intermediary element to connect the first and second pad portions indirectly. This bridge pad unit acts as a mediator that enables electrical connectivity between pad portions while breaking the direct antenna effect path, thereby reducing plasma damage to the gate.
2Ease of manufacture
If pad structure components are directly connected, then manufacturing process is simplified, but plasma damage to gate increases
Solution Approach 1:
The pad structure is segmented into multiple independent pad portions formed in different metal layers (first metal layer, second metal layer, third metal layer). This segmentation prevents direct antenna effect paths while maintaining manufacturability through standard multi-layer metal formation processes.
Solution Approach 2:
The connection between pad portions is achieved by transitioning to another dimension - using vertical stacking of metal layers instead of horizontal direct connection. The bridge pad unit connects pad portions through the vertical dimension (via via units through dielectric layers), reducing plasma damage in the horizontal plane while maintaining connectivity.
3Object-affected harmful factors
If sub-pad portion encircles main conductor units, then plasma damage is reduced, but structural complexity increases
Solution Approach 1:
The sub-pad portion is divided into multiple discrete conductor units (first sub-conductor unit, second sub-conductor unit, third sub-conductor unit) formed in separate metal layers. Each unit independently encircles or is positioned near corresponding main conductor units, collectively achieving plasma damage reduction through distributed geometry rather than a single complex structure.
Solution Approach 2:
The sub-conductor units are positioned to encircle or surround the main conductor units in a nested configuration. The first sub-conductor unit encircles the first main conductor unit, the second sub-conductor unit encircles the second main conductor unit, creating a protective geometric arrangement that reduces plasma damage exposure to the gate.
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
Significantly reduces plasma damage to the gate of MOS devices by isolating the main and sub-pad portions and using specific material and structural designs in the pad bonding and bridge pad units, enhancing the reliability of semiconductor devices.
Implementation Method 1
The pad bonding and bridge pad units are formed using electrodeposition
Data Source
AI summary
A semiconductor device with a pad structure resistant to plasma damage includes: a main pad portion including main conductor units and main via units; a sub-pad portion including sub-conductor units and sub-via units; a pad bonding unit in direct contact with and in connection with a top main conductor unit, wherein the top main conductor unit is the main conductor unit formed in a top metal layer; and a bridge pad unit in direct contact with a top sub-conductor unit, wherein the top sub-conductor unit is the sub-conductor unit formed in the top metal layer. The bridge pad unit is in direct contact with the pad bonding unit. The main pad portion and sub-pad portion are located below the pad bonding unit and bridge pad unit respectively, and the main pad portion and the sub-pad portion are not in direct connection with each other.