Angled Ion Etching for Nanoscale Feature Resizing Without Overlay Error
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Solution Overview
Problem
As semiconductor devices shrink in size, patterning features becomes increasingly difficult due to challenges in achieving target sizes, correct shapes, packing density, and overlay accuracy, particularly with multi-patterning techniques where overlay errors between cut masks and other features on a substrate become significant.
Innovation Solution
The method involves directing ions at a non-zero angle of incidence in a reactive ambient to selectively etch surface features on a substrate, allowing for one-dimensional reactive ion etching that increases dimensions along one direction without affecting perpendicular dimensions, thereby enabling precise control over feature sizes and shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multi-patterning is used to reduce line width and line pitch, then feature size is reduced, but overlay error increases
Solution Approach 1:
The patent replaces conventional lithography-based patterning with ion beam direct writing. The ion beam system uses physical sputtering and deposition mechanisms rather than optical projection, eliminating the overlay accumulation problem inherent in multi-step lithographic processes. Each feature is written directly by the ion beam according to programmed coordinates, achieving sub-10nm precision without multi-patterning overlay errors.
Solution Approach 2:
The patent changes the fundamental patterning parameter from optical wavelength limits to ion beam energy and angle control. By varying ion beam energy (affecting penetration depth), angle of incidence (affecting feature shape), and scanning parameters, the system achieves precise control over feature dimensions and spacing without being constrained by lithographic resolution limits or overlay accumulation.
2Ease of manufacture
If conventional lithography is used for patterning, then process simplicity is maintained, but manufacturing precision deteriorates at advanced nodes
Solution Approach 1:
The patent replaces the complex multi-step lithographic process with a single ion beam direct writing process. Although the ion beam equipment is sophisticated, the patterning process itself is simplified to a single step that directly writes features at their final dimensions, eliminating the multiple alignment and patterning steps required by conventional lithography at advanced nodes.
3Productivity
If feature spacing is reduced to increase packing density, then productivity is improved, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent uses ion beam direct writing with programmable scanning to achieve precise feature placement at reduced spacing. The ion beam system's inherent precision in controlling beam position, energy, and angle allows features to be written at their exact target locations and dimensions, enabling high packing density without sacrificing spacing control even when features are closely spaced.
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 precise patterning of features at the nanoscale, improving packing density and reducing overlay errors, enabling closer tip-to-tip spacing between adjacent features and reducing the number of masks required in the lithography process.
Implementation Method 1
directing first ions in a first exposure to the surface feature along the first direction at a non-zero angle of incidence with respect to a perpendicular to the substrate plane, in a presence of a reactive ambient containing a reactive species; wherein the first exposure etches the surface feature along the first direction
Data Source
AI summary
A method of patterning a substrate. The method may include providing a surface feature on the substrate, the surface feature having a first dimension along a first direction within a substrate plane, and a second dimension along a second direction within the substrate plane, wherein the second direction is perpendicular to the first direction; and directing first ions in a first exposure to the surface feature along the first direction at a non-zero angle of incidence with respect to a perpendicular to the substrate plane, in a presence of a reactive ambient containing a reactive species; wherein the first exposure etches the surface feature along the first direction, wherein after the directing, the surface feature retains the second dimension along the second direction, and wherein the surface feature has a third dimension along the first direction different than the first dimension.