Multi-Portion Shield Electrode Contact for MOSFET Die Shrink
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MOSFET devices face challenges in achieving reduced specific on-resistance, which is crucial for cost reduction and performance improvement, due to difficulties in manufacturing higher density devices with reliable die size reductions, simplified processing, and improved yields.
Innovation Solution
The method involves forming gate dielectric layers before interpoly dielectric layers, using a localized oxidation process to address the thinning effect, and creating a multi-portioned shield contact structure with a flat portion to enhance electrical contact and reduce manufacturing complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If device cells are densely packed to reduce die size, then current carrying capability increases and on-resistance decreases, but manufacturing reliability and yield deteriorate
Solution Approach 1:
The shield electrode contact is divided into multiple portions: a first contact portion extending from the major surface into the contact trench, and a second contact portion within the contact trench contacting the first contact portion. This segmentation allows each portion to be optimized independently for its specific function, improving overall reliability while maintaining dense device packing.
Solution Approach 2:
The shield electrode contact structure extends in multiple dimensions: vertically from the major surface into the contact trench, and horizontally within the contact trench to contact underlying structures. This multi-dimensional approach increases contact area and reliability without increasing the footprint area, enabling denser device packing.
2Area of moving object
If die size is reduced to lower costs, then material and package costs decrease, but manufacturing complexity and yield challenges increase
Solution Approach 1:
The contact structure is segmented into distinct portions formed by different process steps, allowing each segment to be optimized for its specific function. This modular approach simplifies manufacturing by breaking down complex contact formation into manageable steps while achieving compact die size.
Solution Approach 2:
Different portions of the contact structure have different geometric configurations optimized for their local functions: the first contact portion is optimized for vertical contact from the surface, while the second contact portion is optimized for horizontal contact within the trench. This local optimization enables compact design without sacrificing manufacturing simplicity.
3Ease of manufacture
If shield electrode contact structure is simplified, then manufacturing processes are simplified, but electrical contact integrity may deteriorate
Solution Approach 1:
The contact structure is divided into two main portions formed by sequential process steps. This segmentation simplifies manufacturing by allowing each portion to be formed using standard processing techniques while ensuring proper electrical contact through the structured interface between portions.
Solution Approach 2:
The first contact portion is formed in advance extending into the contact trench before the second contact portion is formed. This preliminary action ensures that the foundation for electrical contact is established early, simplifying subsequent processing while guaranteeing contact integrity through the pre-positioned first contact portion.
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 approach facilitates a die shrink to 0.8 microns or less, improving specific on-resistance, yield, and shield electrode contact integrity, thereby addressing the limitations of existing MOSFET devices.
Implementation Method 1
using a localized oxidation process to address the thinning effect
Data Source
AI summary
In one embodiment, a method for forming a semiconductor device having a shield electrode includes forming first and second shield electrode contact portions within a contact trench. The first shield electrode contact portion can be formed recessed within the contact trench and includes a flat portion. The second shield electrode contact portion can be formed within the contact trench and makes contact to the first shield electrode contact portion along the flat portion.