Semiconductor Fin Formation With Region-Specific Etch Profiles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for forming fin structures in semiconductor devices face challenges in controlling the taper angle and width of fins, leading to variations in shape, which can result in decreased reliability and performance of the semiconductor device.
Innovation Solution
A method involving the preparation of a semiconductor substrate with distinct regions, forming patterns, and performing anisotropic etching processes to create fins with varying angles and widths, ensuring the formation of different fin structures for specific regions to achieve optimal properties for low-voltage, high-voltage MISFETs, and non-volatile memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different etching conditions are used to form different fin structures in different regions, then the fin structures can be differentiated for different semiconductor elements, but the taper angle and width of each fin become difficult to control and variation in fin shape increases
Solution Approach 1:
The patent applies preliminary action by forming a mandrel pattern before the etching process. This mandrel serves as a pre-formed structure that defines the fin shape, allowing subsequent etching to proceed with consistent geometry. The mandrel is formed in advance and selectively removed after fin formation, enabling precise control of fin taper angles and widths while still allowing different fin structures in different regions through selective mandrel formation or modification.
Solution Approach 2:
The mandrel acts as an intermediary structure between the patterning step and the fin formation step. It mediates the transfer of the desired fin geometry to the semiconductor substrate during etching, ensuring that the fin structures achieve the intended taper angles and widths. The mandrel is selectively formed or modified in different regions to create different fin structures, while maintaining consistent etching conditions across all regions.
2Ease of manufacture
If fin structures are formed without precise control, then manufacturing process is simpler, but reliability and performance of the semiconductor device decrease
Solution Approach 1:
The mandrel is formed in advance as a preliminary structure that guides the etching process. This preliminary action ensures that fins are formed with controlled geometry without requiring complex real-time control during etching. The mandrel's predetermined shape directly translates to controlled fin geometry, achieving both ease of manufacture and high reliability.
Solution Approach 2:
The mandrel structure serves itself as the etching mask and geometry template. By being formed with precise dimensions and then used to define the fin geometry during etching, the mandrel automatically ensures consistent fin shapes without requiring additional control mechanisms. The structure that defines the fin geometry also serves as the etching barrier, simplifying the overall process while maintaining precision.
3Ease of manufacture
If uniform fin structures are used across all regions, then manufacturing process is simplified, but different semiconductor elements cannot achieve their optimal properties
Solution Approach 1:
The patent applies segmentation by dividing the semiconductor substrate into different regions, each with its own mandrel structure tailored to the specific requirements of the semiconductor elements in that region. Low-voltage MISFET regions, high-voltage MISFET regions, and non-volatile memory regions each receive customized mandrel patterns that produce the appropriate fin structures for their specific electrical characteristics and performance requirements.
Solution Approach 2:
The mandrel structures are formed with locally optimized properties for each region. The width, height, and taper angle of mandrels are adjusted according to the specific needs of the semiconductor elements in each region. This local quality approach allows different fin structures to be created using the same basic etching process, maintaining ease of manufacture while achieving region-specific optimization.
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 enhances the reliability and performance of semiconductor devices by securing the width of fins, preventing electric field concentration and punch-through phenomena, thereby improving the breakdown voltage and microfabrication capabilities.
Implementation Method 1
performing an anisotropic etching process to the semiconductor substrate in a state in which the first pattern is left on the semiconductor substrate in the first region while the first and the second patterns are left on the semiconductor substrate in the second region
Data Source
AI summary
Reliability and performance of a semiconductor device are improved. First, a first mask pattern is formed on the semiconductor substrate in each of first to third regions. Next, a second mask pattern made of a material that is different from a material configuring the first mask pattern is formed on a side surface of the first mask pattern and on the semiconductor substrate in each of the first to third regions. Next, by an anisotropic etching process performed to the semiconductor substrate, a plurality of fins protruding from the recessed upper surface of the semiconductor substrate are formed. In the manner, fins each having a different structure from that of a fin in the first region can be formed in the second and third regions.