FinFET Gate Line Placement via Inverted Slot-Cut Process
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Solution Overview
Problem
The existing slot-cut first process for fabricating FinFETs results in a loading effect when coating organic dielectric layers, affecting the yield of the process and failing to meet the requirements of miniaturized semiconductor devices for high integration, performance, and low power consumption.
Innovation Solution
A method involving the formation of trench isolation regions and fin structures, deposition of a polysilicon layer, creation of poly and dummy openings, coating with an organic dielectric layer, and patterning with photoresist lines to form poly lines that do not overlap with dummy regions, followed by a replacement metal gate process to achieve optimized gate line placement and height control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the slot-cut first process is used to form poly lines in FinFET fabrication, then the gate line placement can be achieved, but a loading effect occurs when coating the organic dielectric layer (ODL), affecting process yield
Solution Approach 1:
The patent applies preliminary action by forming the poly lines before coating the organic dielectric layer (ODL), rather than cutting them after ODL deposition. This reverses the conventional slot-cut first process sequence, allowing the ODL to be coated uniformly without encountering the loading effect that occurs when trying to pattern through already-deposited layers. The poly lines are formed in advance on the substrate, then the ODL is coated over them, eliminating the yield-affecting loading effect while maintaining precise gate line placement.
2Ease of manufacture
If the polysilicon layer is patterned early to form poly lines, then gate structure definition is achieved, but the loading effect during ODL coating reduces manufacturing efficiency
Solution Approach 1:
The patent inverts the conventional process sequence by forming poly lines before ODL coating instead of after. In the traditional approach, the slot-cut process is performed first to define gate lines, then ODL is coated. The patent reverses this: poly lines are formed initially, then ODL is coated over them without causing loading effects. This inversion resolves the contradiction by maintaining ease of gate structure definition while eliminating the productivity-reducing loading effect during ODL coating.
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 enhances the manufacturing process by reducing the loading effect, improving yield, and enabling the formation of FinFETs with precise gate line placement and height control, addressing the limitations of the prior art in achieving high drive currents and alleviating short channel effects.
Implementation Method 1
A polysilicon layer is deposited over the substrate
Implementation Method 2
An organic dielectric layer (ODL) is coated over the substrate. The ODL fills into the poly cut opening and the dummy opening
Implementation Method 3
A plurality of photoresist line patterns comprising a first photoresist line pattern and a second photoresist line pattern are formed. The photoresist line patterns extend along a second direction on the hard mask layer
Data Source
AI summary
A semiconductor device includes a substrate having a fin structure extending along a first direction. The fin structure protrudes from a top surface of a trench isolation region and has a first height. A plurality of gate lines including a first gate line and a second gate line extend along a second direction and striding across the fin structure. The first gate line has a discontinuity directly above a gate cut region. The second gate line is disposed in proximity to a dummy fin region, and does not overlap with the dummy fin region. The fin structure has a second height within the dummy fin region, and the second height is smaller than the first height.