Raised-Rib Liner Structure for Ion Implanter Particle Control
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Solution Overview
Problem
Ion implantation processes in semiconductor manufacturing suffer from particle excursions and deposition of sputtered materials on internal surfaces, leading to damage and contamination of workpieces due to the transport of loose particles by the ion beam.
Innovation Solution
A liner with periodically-spaced raised ribs is introduced, fabricated from materials like graphite or SiC-coated graphite, featuring angled surfaces to prevent the ion beam from striking and lifting particles, thereby reducing particle transport and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If removable liners are used to cover internal surfaces, then component damage is prevented and cleaning is simplified, but particle transport by the ion beam to workpieces continues to occur
Solution Approach 1:
The liner surface is segmented into multiple raised ribs that create distinct regions. These ribs divide the continuous surface into separated zones, preventing the ion beam from continuously sweeping across a flat surface and lifting particles. The segmentation creates shadow regions behind each rib where particles are shielded from ion beam transport.
Solution Approach 2:
The liner transitions from a two-dimensional flat surface to a three-dimensional structured surface with raised ribs. This dimensional change creates vertical relief features that cast shadows and block the ion beam's line-of-sight transport path, adding a vertical dimension to particle protection that a flat surface cannot provide.
2Productivity
If high beam current is used for ion implantation, then processing efficiency is improved, but large particle excursions occur that damage workpiece devices
Solution Approach 1:
The raised ribs act as intermediary structures between the ion beam and the liner surface. They intercept and block the ion beam before it can directly strike and lift large particles from the surface, serving as a protective mediator that allows high beam current operation without proportionally increasing particle excursion damage.
3Ease of manufacture
If photoresist material is applied to workpieces, then device fabrication is enabled, but sputtered photoresist material builds up on liner surfaces creating particles
Solution Approach 1:
The raised ribs extract or remove the problematic flat surface area from direct ion beam exposure. By elevating portions of the liner surface vertically, the design separates the photoresist deposition zones from the ion beam path, allowing photoresist to be applied to workpieces while preventing its sputtered material from building up on surfaces that would generate particles.
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
The liner effectively inhibits the transport of loose particles by maintaining a distance from the ion beam, reducing particle excursions and minimizing contamination on workpieces, thus enhancing the integrity of semiconductor fabrication processes.
Implementation Method 1
As the ion beam strikes surfaces within the implanter, such as the workpiece or hardware components, it causes atoms to be sputtered from and larger particles to be liberated from the surfaces
Implementation Method 2
These atoms and larger particles then deposit themselves on other surfaces and can form a poorly-adhering thin film or loose particles. The particles can be transported by the ion beam from surfaces in the ion implanter back to the workpiece
Data Source
AI summary
A liner for an ion implanter includes a base and a plurality of ribs extending from a surface of the base. Each of the ribs includes a first surface that extends at an angle from the surface of the base toward a distal end and a second surface that extends from the distal end toward the surface of the base at a non-perpendicular angle.