Hard Mask Contact Etching for Semiconductor Miniaturization
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Solution Overview
Problem
Conventional self-aligned contact (SAC) etching processes are inadequate for manufacturing smaller integrated circuit devices, offering limited margin of error and requiring large spacer thicknesses to prevent exposure of address lines during etching, which restricts the miniaturization of semiconductor features.
Innovation Solution
A method for contact etching that eliminates the need for spacers as etching guides by using a hard mask and anisotropic etching to form a smaller exposed region, allowing for more compact spacing between address lines and enabling the formation of smaller contact holes without relying on spacers for alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional self-aligned contact (SAC) etching processes are used, then alignment is achieved through spacers, but spacer thickness must be large to prevent exposure of address lines, restricting miniaturization
Solution Approach 1:
The patent extracts the etching guide function from the spacer structure and transfers it to a dedicated hard mask layer. This separation allows the spacer to be optimized for its primary function (isolation) while the hard mask provides precise etching alignment, enabling smaller feature sizes without compromising alignment precision.
Solution Approach 2:
The patent introduces a hard mask layer as an intermediary between the spacer structure and the etching process. This hard mask serves as the actual etching guide, decoupling the alignment function from the spacer thickness and enabling precise contact hole formation with smaller features.
2Reliability
If large spacer thicknesses are used to prevent address line exposure, then etching alignment is maintained, but device miniaturization is restricted
Solution Approach 1:
The patent extracts the process margin function from the spacer thickness and concentrates it in the hard mask layer. The hard mask can be optimized for etching selectivity and thickness control independent of the spacer dimensions, maintaining reliability while enabling miniaturization.
Solution Approach 2:
The patent applies different material properties and thicknesses to different layers: the spacer provides structural isolation with optimized dimensions, while the hard mask provides etching protection with optimized thickness and material properties specifically for the etching process, allowing each layer to be optimized for its specific function.
3Manufacturing precision
If spacers are used as etching guides, then alignment is achieved, but thermal budget increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts the etching guide function from the spacer and assigns it to the hard mask layer. This separation simplifies the spacer design (only needs to provide isolation) and allows the hard mask to be optimized specifically for etching guidance, reducing overall process complexity.
Solution Approach 2:
The hard mask layer serves multiple functions: it provides etching guidance, defines the contact hole pattern, and can serve as an etch stop layer. This multi-functionality reduces the need for additional process steps and materials, simplifying the overall manufacturing process.
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 allows for the manufacturing of smaller integrated circuit devices with increased process margin and reduced thermal budgets, while being compatible with conventional technology and equipment, enabling more efficient and precise contact formation.
Implementation Method 1
performing anisotropic etching the thickness of the spacer material to form a second exposed region within the first exposed region
Implementation Method 2
Etching is an important process in semiconductor manufacturing. Etching involves removing selected regions from the surface of a wafer using physical process, chemical process, or the combination thereof
Implementation Method 3
Chemical drying etching usually involves generating reactive species in plasma, diffusing these species to the surface of material being etched
Data Source
AI summary
System and method for direct etching. According to an embodiment, the present invention provides a method for manufacturing an integrated circuit device. The method includes a step for providing a substrate having a contact region, which is provided between a first word line and a second word line. The contact region has an overlying plug structure, which is provided within a thickness of a first dielectric layer. The first dielectric layer includes a portion overlying the plug structure. The first dielectric layer has a planarized surface region. The method also includes a step for forming a first line and a second line and a space provided between the first word line and the second world line. The space is provided within a region overlying the plug structure.