Trench Electrode Contact Layout With Self-Aligned Openings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The reduction in size of semiconductor devices is hindered by misalignment issues in the photolithography process, leading to electrical differences and potential short circuits, which conventional methods struggle to overcome effectively.
Innovation Solution
The development of semiconductor devices with self-aligned contacts, where a dielectric cap layer and spacers are used to form contact openings without relying on photolithography, ensuring precise alignment and positioning of electrode contacts between trench electrodes, suitable for devices with pitches as small as 0.2 μm to 0.65 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photolithography process is used to form openings for electrode contacts, then the fabrication process is simple and straightforward, but misalignment occurs causing position shifts and electrical defects
Solution Approach 1:
The patent applies preliminary action by forming the dielectric cap layer and spacer structures on the trench electrodes before defining the contact openings. The spacers are deposited and etched back to create self-aligned reference structures that predetermined the exact position where contact openings will be formed, eliminating alignment issues that would occur during subsequent photolithography steps
Solution Approach 2:
The patent implements self-service through self-aligned contacts where the contact openings are defined by the physical structures already present on the device (trench electrodes and spacers) rather than by external photolithography alignment. The spacers automatically serve as alignment references that guide the formation of contact openings at precisely the correct positions without requiring additional alignment capability from exposure equipment
2Area of moving object
If semiconductor device size is reduced to increase integration density, then more devices can be packed in smaller area, but photolithography alignment capability becomes insufficient leading to misalignment and device failure
Solution Approach 1:
The patent transitions from two-dimensional photolithography alignment to three-dimensional self-aligned structures by forming vertical spacer structures on the trench electrodes. This dimensional transition allows the contact openings to be precisely positioned in the lateral direction through the vertical spacer height and width, enabling accurate alignment even as device dimensions are reduced to increase integration density
Data Source
AI summary
A semiconductor device includes a substrate, a body region on the substrate, a source region on the body region, a first trench electrode passing through the source region, the body region and a portion of the substrate, a first dielectric cap layer, a first dielectric liner and a conductive layer. The first dielectric cap layer includes a first dielectric portion directly above the first trench electrode and first dielectric spacers on two opposite sides of the first dielectric portion. The first dielectric liner surrounds the first trench electrode and the first dielectric portion. The conductive layer covers the first dielectric cap layer and includes an electrode contact. The electrode contact includes a first portion in the body region and a second portion adjacent to one of the first dielectric spacers, where the first and second portions have the same width.