Semiconductor Gate Stack Cap Structure for Reliable Sub-10nm Etching
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Solution Overview
Problem
The semiconductor industry faces challenges in forming reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, leading to issues with processing and manufacturing efficiency.
Innovation Solution
A method for forming a semiconductor device structure involving the formation of fin structures, isolation features, gate dielectric layers, gate electrodes, spacer elements, and metal gate stacks, with specific etching operations to create a recess for the metal gate stack and a cap element, improving the formation and integration of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are decreased to increase functional density, then production efficiency and cost are improved, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple sequential steps including forming mandrel structures, depositing first spacers, forming second spacers, and creating recesses. Each step builds upon the previous one, breaking down the complex task of creating sub-10nm features into manageable stages that can be executed with existing process tools and techniques.
Solution Approach 2:
Mandrel structures are formed in advance as templates before the actual transistor structures are created. These mandrels serve as preliminary guides that define the positions and dimensions of subsequent features, allowing precise patterning to be achieved through a series of controlled deposition and etching steps rather than requiring direct single-step patterning at the final dimensions.
2Area of stationary object
If feature sizes are decreased to increase functional density, then chip area utilization is improved, but manufacturing reliability deteriorates
Solution Approach 1:
Spacer structures serve as intermediary elements that transfer the pattern definition from the mandrel structures to the final transistor features. The spacers act as intermediate templates that can be precisely controlled in thickness through deposition processes, enabling reliable dimension control at sub-10nm scales without directly relying on photolithography resolution limits.
Solution Approach 2:
The invention controls feature dimensions by adjusting deposition parameters (such as thin film thickness) and etching parameters rather than relying solely on lithographic resolution. By changing process parameters like spacer thickness and recess depth, precise control over final feature dimensions is achieved, maintaining manufacturing reliability even as feature sizes decrease.
Data Source
AI summary
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a gate stack over a semiconductor substrate and a cap element over the gate stack. The cap element has an upper portion and a lower portion, and the upper portion is wider than the lower portion. The semiconductor device structure also includes a spacer element over a sidewall of the cap element and a sidewall of the gate stack.