Fin Structure Multi-Implantation for Uniform FinFET Doping
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Solution Overview
Problem
Existing FinFET devices face challenges in achieving uniform doping profiles due to non-planar structures, leading to non-linearity in capacitance and reduced device performance, particularly in analog-rich circuit designs like image signal processors.
Innovation Solution
A method involving multi-implantation cycles with varying energies and tilt angles is applied to fin structures, followed by a well anneal, to achieve uniform dopant distribution and improve capacitance linearity, using techniques like double-patterning lithography and insulation material deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single implantation method is used on FinFET structures, then the process is simple, but the dopant distribution is non-uniform leading to capacitance non-linearity
Solution Approach 1:
The implantation process is divided into multiple sequential steps (first implantation, second implantation, third implantation) with different energies and tilt angles. Each step targets specific regions of the fin structure to achieve cumulative uniform dopant distribution that cannot be achieved with a single implantation step.
Solution Approach 2:
The implantation parameters (energy, tilt angle, dose) are systematically changed between steps. The first implantation uses higher energy with a first tilt angle, the second uses lower energy with a second tilt angle, and the third uses yet different parameters, allowing precise control of dopant penetration depth and lateral distribution to achieve uniformity.
2Manufacturing precision
If multi-implantation cycles with varying energies and tilt angles are applied, then dopant distribution uniformity is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The complex implantation requirement is segmented into three manageable sequential steps, each with specific energy and tilt angle parameters. This segmentation makes the complex task of achieving uniform dopant distribution in 3D FinFET structures achievable through systematic, repeatable process steps.
Solution Approach 2:
The first implantation step performs a preliminary doping action that establishes a base dopant distribution. Subsequent implantation steps build upon this preliminary distribution, adding dopants to specific regions to correct non-uniformities and achieve the final uniform concentration profile.
3Productivity
If FinFET structures are used to increase functional density, then circuit capacity increases, but doping uniformity becomes more difficult to achieve
Solution Approach 1:
The implantation process transitions from conventional planar (2D) implantation to 3D spatially-resolved implantation by utilizing tilt angles. The first tilt angle targets sidewall regions while the second tilt angle targets top region regions, effectively using angular dimensions to address the 3D doping uniformity challenge in vertically-oriented FinFET structures.
Solution Approach 2:
Different regions of the fin structure receive different implantation treatments. The first implantation with first tilt angle predominantly dopes the sidewall regions, while the second implantation with second tilt angle predominantly dopes the top region. This local quality approach ensures each region achieves its required dopant concentration for optimal device performance.
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
The method results in improved uniformity of dopant concentration along the fin structure, enhancing device performance by reducing capacitance non-linearity and improving the overall performance of FinFET devices.
Implementation Method 1
applying a plurality of ion implantation cycles to the fin structures
Implementation Method 2
a well anneal is performed
Implementation Method 3
a well anneal is performed
Data Source
AI summary
A method of manufacturing a semiconductor structure, comprising providing a substrate; forming a fin structure over the substrate; depositing an insulation material over the fin structure; performing a plurality of ion implantation cycles in-situ with implantation energy increased or decreased stepwise; and removing at least a portion of the insulation material to expose a portion of the fin structure.