Multi-Layer Gate Spacers for FinFET Etch Resistance
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing damage during the manufacturing of FinFETs while maintaining a suitable dielectric constant, which affects the integration density and performance of electronic components.
Innovation Solution
The use of seal spacers, specifically a multi-layer spacer structure comprising a first outer shell and a first bulk dielectric material with different compositions, is introduced to enhance etch resistance and reduce dielectric constant, thereby minimizing damage and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If single-layer spacer structures are used, then manufacturing process is simpler, but etch resistance is insufficient causing damage to underlying layers
Solution Approach 1:
The spacer structure is divided into multiple layers with different materials (e.g., silicon nitride, silicon oxynitride, silicon oxide) stacked vertically. Each layer provides specific functionality: the bottom layer offers etch resistance against silicon dioxide, the middle layer provides etch resistance against silicon nitride, and the top layer maintains dielectric constant. This segmentation allows the spacer to resist multiple types of etching damage simultaneously.
Solution Approach 2:
The spacer employs composite material construction combining different dielectric materials with complementary properties. By stacking materials with varying etch selectivities and dielectric constants, the composite structure achieves superior overall performance that no single material could provide alone, particularly in resisting diverse etching conditions while maintaining electrical properties.
2Reliability
If high dielectric constant materials are used in spacers, then capacitance is higher improving device performance, but etch resistance during manufacturing is reduced increasing damage
Solution Approach 1:
Different regions of the spacer structure have different material compositions optimized for their specific functions. The bottom layers use materials with high etch resistance for their respective layers, while the top layer uses materials with appropriate dielectric constant for electrical performance. This local optimization allows each part of the spacer to excel at its primary function without compromising the whole.
Solution Approach 2:
The solution moves from considering a single-material spacer to a multi-layer vertical structure, adding the dimensional aspect of layering. This vertical differentiation allows simultaneous optimization of etch resistance (in lower layers) and dielectric constant (in upper layers), resolving the contradiction by distributing properties across different spatial dimensions.
Data Source
AI summary
Semiconductor devices and methods of manufacture are presented in which spacers are manufactured on sidewalls of gates for semiconductor devices. In embodiments the spacers comprise a first seal, a second seal, and a contact etch stop layer, in which the first seal comprises a first shell along with a first bulk material, the second seal comprises a second shell along with a second bulk material, and the contact etch stop layer comprises a third bulk material and a second dielectric material.