Gate Spacer Structure Using Boron Nitride to Cut Parasitic Capacitance
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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 parasitic capacitance and mechanical reliability.
Innovation Solution
The use of boron- and nitrogen-containing materials with a hexagonal ring structure, such as hexagonal boron nitride and hexagonal boron carbon nitride, is employed to form ultra-low-k spacer, etch stop, and cap layers, which reduce dielectric constant and enhance mechanical properties, improving device performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used in semiconductor fabrication, then manufacturing processes can be performed, but parasitic capacitance increases and mechanical reliability decreases at smaller feature sizes
Solution Approach 1:
The patent changes the dielectric constant parameter by introducing ultra-low-k materials with k values less than 2.0, replacing conventional materials. This parameter change directly reduces parasitic capacitance while the specific material composition (boron- and nitrogen-containing materials with hexagonal ring structures) provides enhanced mechanical properties to address reliability concerns at scaled dimensions
Solution Approach 2:
The patent employs composite material structures including boron- and nitrogen-containing materials with hexagonal ring structures combined with other dielectric materials. These composite structures achieve both low dielectric constant for reduced parasitic capacitance and high mechanical strength for improved reliability, resolving the contradiction between electrical and mechanical performance requirements
2Productivity
If feature sizes are decreased to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity and difficulty increase
Solution Approach 1:
The patent changes the material composition parameters to include boron- and nitrogen-containing materials with specific hexagonal ring structures. These material parameter changes enable fabrication processes to proceed more reliably at smaller feature sizes by providing better etch selectivity, deposition characteristics, and mechanical stability, thereby reducing process complexity despite scaling
3Object-affected harmful factors
If conventional dielectric materials are used, then device structure can be formed, but dielectric constant is high leading to increased parasitic capacitance
Solution Approach 1:
The patent fundamentally changes the dielectric constant parameter by using ultra-low-k materials with k < 2.0, replacing conventional materials with higher k values. This parameter change directly reduces parasitic capacitance. The specific chemical composition (boron- and nitrogen-containing materials with hexagonal ring structures) simultaneously provides high mechanical strength and etch selectivity, ensuring device performance and reliability are maintained or improved
Data Source
AI summary
A method for forming a semiconductor device structure is provided. The method includes forming a gate stack over a substrate. The method includes forming a spacer over first sidewalls of the gate stack using a first precursor. The first precursor includes a first boron- and nitrogen-containing material having a first hexagonal ring structure, the spacer has a plurality of first layers, and each first layer includes boron and nitrogen.