ChemGuard refill technology

DESCRIPTION

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The system is comprised of three modules: 

(1)    The bulk cabinet – a small footprint (0.11sq meter) chemical cabinet that supplies chemical to four diffusion furnaces via the VMB.
(2)    The Valve Manifold Box (VMB) mounts inside the furnace and distributes chemical to all the individual stacked tubes via the SCM.
(3)    The chemical Source Control Module (SCM) manages the refill-function at each tube furnace.

The compact Bulk cabinet can be installed in the proximity of the diffusion furnaces (up to four) and is easily facilitated as it only requires the facilities that are pre-existing at each furnace. The cabinet includes a user friendly color-touch controller that provides control windows to the whole system and automatically runs refill requests and bulk change-out sequences.  The VBM has been designed to be leak tight and small enough to fit inside a multi tube furnace.   Finally, the SCM uses highly innovative technology to manage the refill function in a safe and efficient manner.

INNOVATIVE ASPECT

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The chemical (POCl3) used to dope phosphorous into c-Si wafers in highly poisonous and highly corrosive. Even small traces of residue can cause health issues and / or damage to equipment.

The technological breakthroughs of the CG1000 design are in the proprietary design of custom valve manifolds used in the bulk cabinet, VMB and SCM; and in the optimized purge sequences developed to produce ultra low levels of chemical residue inside the container connections.
The following test data summarizes performance test data (confidential):

The graph shows measured concentration levels of HCl (a byproduct of reacted POCl3) that remain inside the container connections during the bulk container replacement operation.  (The complete replacement operation takes 1.5 hours in which the connections are disconnected for only 5 minutes.)   The purge manifold design with optimized purge sequences yields concentration levels that are 10 times lower than the permissible exposure limits as defined by OSHA – a US government agency.  These results ensure the safety of the operator and all employees on site.

Without this system operators need to replace near-empty (15%) quartz containers with full ones at a rate of 4 to 10 times per month for each diffusion furnace.  The containers are very delicate and will easily break causing a spill over a large area.  The operators typically wear the Proper Protective Equipment when climbing to the location (up to 2 meters in height) of the bubblers; but there is no guarantees that others in the vicinity are also wearing respirators or that the operator’s own respirator will continue to function if they fell from a height of 2 meters.

The end result of the product is a robust auto-refill system that eliminates the need to shut down production and risk chemical exposure to operators during the chemical resupply exercise.

BENEFITS

The key benefits of this product are: 

Eliminate expensive diffusion tool downtime due to chemical container replacements
Reduce chemical handling costs by 94%
Significantly reduce the purchase price of chemical by buying in bulk (17.0L vs 1.5L)
Eliminate 15% wasted chemical by utilizing 100% of the purchased chemical
Minimizing risk of exposure to chemical will lead to:
Reduce Emergency Response Team support costs
Reduced Personal Protective Equipment costs (up to 90%)
Reduced incidents of contamination that lead to diffusion tool downtime
Reduce incidents of chemical exposure that can be extremely dangerous and even fatal.

Overall, the manufacturing benefits will help generate the cost savings required to produce c-Si cells that can compete with electricity grid prices.

The following presentation provides background information and additional details of the system.