Reduced Thickness Shutter Flange for PVD Shadow Tab Mask
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Solution Overview
Problem
The interaction between shadow tab masks and prior art shutters in PVD chambers leads to issues such as explosive release of Titanium/Titanium Nitride particles due to broken fused seams, loose bonding of particles on surfaces due to gaps, and balancing problems, which affect the conditioning process and wafer adhesion.
Innovation Solution
A shutter with a circumferential flange of reduced thickness is used, preventing the formation of a fused seam between the shadow tab mask and the shutter, thereby minimizing particle dispersal and ensuring proper alignment and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shutter with uniform thickness is used to shield the heater table during PVD chamber conditioning, then the heater table is protected from Titanium/Titanium Nitride deposition, but a fused seam forms between the shadow tab mask and shutter that causes explosive particle release when the mask is removed
Solution Approach 1:
The shutter employs varying thickness across different regions: a first thickness for the main body and a second, smaller thickness for the circumferential flange portion. This local quality differentiation prevents fused seam formation at the interface with the shadow tab mask while maintaining adequate protection elsewhere.
Solution Approach 2:
The shutter is segmented into distinct thickness zones, with the circumferential flange having reduced thickness compared to the main body. This segmentation allows the flange region to function differently (preventing fused seams) while the main body continues to provide primary shielding.
2Ease of manufacture
If a uniform thickness shutter is used, then manufacturing is simplified, but gaps form between the shadow tab mask and heater table causing loose particle bonding
Solution Approach 1:
The shutter design implements local quality variation with reduced thickness at the circumferential flange portion. This localized modification improves particle adhesion by preventing gap formation while maintaining overall manufacturing feasibility through a relatively simple geometric modification.
3Manufacturing precision
If the shadow tab mask rests directly on the heater table, then alignment marking coverage is achieved, but balancing problems occur during the deposition process
Solution Approach 1:
The circumferential flange of the shutter acts as an intermediary element between the shadow tab mask and the heater table. This flange provides a stable resting surface for the mask during deposition, preventing balancing issues while allowing the tabs to properly cover alignment marks on the heater table.
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 reduced thickness circumferential flange of the shutter prevents particle explosion and backscatter, ensuring better adhesion and balancing, thus enhancing the conditioning process in PVD chambers.
Implementation Method 1
a system and method for providing an improved shutter for use with a shadow tab mask and heater table during a conditioning process for a physical vapor deposition (PVD) chamber
Data Source
AI summary
A system and method is disclosed for providing an improved shutter for use with a shadow tab mask and heater table during a conditioning process for a physical vapor deposition (PVD) chamber. A shutter for covering the heater table is provided that has a circumferential flange with a thickness that is less than a thickness of the non-circumferential flange portions of the shutter. A shadow tab mask having a portion that extends over the flange portion is placed on the heater table. When deposition material is subsequently deposited, the reduced thickness of the flange portion prevents a fused seal from being formed between deposition material deposited on the shadow tab mask and deposition material deposited on the circumferential flange of the shutter.