Inorganic Block Mask for Non-Mandrel Cut Interconnects
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Solution Overview
Problem
Existing self-aligned multiple patterning processes in semiconductor device fabrication face issues with pillar flapping and missing pillars due to the low hardness and weak adhesion of organic materials used in spin-on hardmasks, leading to systematic defects in interconnect structures.
Innovation Solution
The method involves depositing a hardmask over a dielectric layer and forming block masks from inorganic dielectric materials like titanium dioxide or silicon dioxide, which are used to create non-mandrel cuts and mandrel cuts, overcoming the limitations of organic materials by providing improved etch selectivity and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic materials are used for spin-on hardmask patterning, then the patterning process can be performed, but pillar flapping and missing pillars occur due to low hardness and weak adhesion
Solution Approach 1:
The patent changes the material parameter from organic to inorganic dielectric material, fundamentally altering the physical properties including hardness and adhesion characteristics. This parameter change resolves the contradiction by providing both manufacturability through deposition processes and reliability through improved mechanical properties of inorganic materials
Solution Approach 2:
The patent employs composite material structures by forming inorganic dielectric layers over organic underlayers. The inorganic layer provides the necessary hardness and adhesion for reliable patterning, while the composite structure maintains the ease of manufacture through sequential deposition and processing steps
2Ease of manufacture
If spin-on hardmask is used for forming cuts, then the process can be completed, but poor macro-loading occurs during reactive ion etching
Solution Approach 1:
The patent changes the material composition parameter from organic to inorganic dielectric material, which fundamentally improves the etching characteristics. Inorganic materials provide better macro-loading during reactive ion etching, ensuring uniform etch rates and precise cut formation without the deficiencies of organic materials
3Ease of manufacture
If mandrel cuts and non-mandrel cuts are formed using organic pillars, then the interconnect pattern can be defined, but systematic defects are introduced
Solution Approach 1:
The patent changes the material parameter of the etch mask from organic to inorganic dielectric material. This parameter change simultaneously achieves easy pattern definition through standard deposition processes and high cut accuracy through the superior mechanical and etching properties of inorganic materials, eliminating systematic defects
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 reduces the occurrence of pillar flapping and missing pillars, thereby minimizing systematic defects in the interconnect structure and ensuring more reliable interconnect formation.
Implementation Method 1
A self-aligned multiple patterning process is used to form trenches in a dielectric layer. An inorganic dielectric material layer is formed over an organic underlayer, and the inorganic dielectric material layer is patterned to define mandrel cuts and non-mandrel cuts
Data Source
AI summary
Methods of fabricating an interconnect structure. A hardmask is deposited over a dielectric layer, and a block mask is formed that is arranged over an area on the hardmask. After forming the block mask, a first mandrel and a second mandrel are formed on the hardmask. The first mandrel is laterally spaced from the second mandrel, and the area on the hardmask is arranged between the first mandrel and the second mandrel. The block mask may be used to provide a non-mandrel cut separating the tips of interconnects subsequently formed in the dielectric layer.