Dielectric Fin Spacers for Precise Gate Electrode Trenching
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Solution Overview
Problem
The fabrication processes on the backside of semiconductor substrates, such as those involving through-silicon-via (TSV) connections, often have larger process windows than those on the frontside, complicating the manufacturing of semiconductor devices as they become smaller.
Innovation Solution
A method is developed that involves forming spacers on the sides of dielectric structures during the manufacturing process, which includes patterning fin structures, embedding them in an insulating layer, forming sacrificial gate structures, and using sidewall spacers to define source/drain regions, followed by epitaxial layer formation and gate dielectric and electrode creation, allowing for precise control of the semiconductor device's structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If fabrication processes are performed on the backside of semiconductor substrates to accommodate smaller device sizes, then device scaling is enabled, but process complexity and difficulty increase due to larger process windows required for TSV connections
Solution Approach 1:
The fabrication process is divided into separate frontside and backside operations, with each side optimized independently. The substrate is processed on the frontside first, then flipped for backside TSV formation, allowing each process to operate within its optimal parameters without interference from the other side's constraints
Solution Approach 2:
Frontside processing is completed before substrate flipping to prepare the structure for backside operations. This preliminary preparation ensures that when backside TSV processes are performed, the frontside structures are already in place and properly configured, reducing the complexity of coordinating both sides simultaneously
2Manufacturing precision
If spacers are formed on sides of dielectric structures, then pattern definition precision is improved, but manufacturing steps and process complexity increase
Solution Approach 1:
Spacers are introduced as intermediary structures formed on the sides of dielectric structures. These spacers serve as self-aligned masks that define precise patterns for subsequent etching steps, eliminating the need for separate photolithography alignment steps and actually reducing overall process complexity while improving precision
Solution Approach 2:
The spacer structures are formed in advance before the critical patterning steps. This preliminary formation establishes precise geometric references that guide subsequent material deposition and etching, ensuring high pattern definition precision without requiring complex real-time alignment procedures
3Reliability
If sidewall spacers are used to define source/drain regions, then electrical separation is improved, but device structure complexity increases
Solution Approach 1:
Sidewall spacers act as intermediary structures that physically separate source and drain regions. These spacers provide electrical isolation and define the boundaries between regions, enabling reliable device operation while maintaining a relatively simple overall structure that can be formed using standard semiconductor fabrication techniques
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 method enhances the precision and fidelity of semiconductor device manufacturing by improving pattern definition and electrical separation, enabling efficient formation of gate-all-around FETs and fin FETs, even on smaller scales.
Implementation Method 1
spacers are formed on opposite sides of the dielectric fin structure
Implementation Method 2
a trench is etched through the gate electrode using the dielectric fin and the spacers as masks
Implementation Method 3
followed by epitaxial layer formation
Data Source
AI summary
In a method of manufacturing a semiconductor device, a FET structure is formed over a substrate, which includes a plurality of semiconductor sheets vertically arranged over a bottom fin structure, a gate dielectric layer wrapping around each of the plurality of semiconductor sheets, a gate electrode disposed over the gate dielectric layer and a source/drain structure. A gate cap conductive layer is formed over the gate electrode, the bottom fin structure is replaced with a dielectric fin structure, spacers are formed on opposite sides of the dielectric fin structure, a trench is formed by etching the gate electrode using the dielectric fin and the spacers as an etching mask until the gate cap conductive layer is exposed, and the trench is filled with a first dielectric material.