Glass: Clean Chemical Delivery
This paper looks at the challenges posed by relying on traditional glass bottles to pack, store, ship, and deliver clean process chemicals, alternatives that have been explored, and a viable solution to these challenges.
As the semiconductor industry continues to chase or replace Moore’s Law by scaling to smaller nodes and/or adopting complex architectures like 3D NAND, the spotlight is often on process optimization and improved chemistry formulation. It seems little thought is given to the ancillary technologies that are just as important for achieving requirements for today’s fine features and complicated structures. Chemical delivery to and throughout the semiconductor fabrication (fab) process flow is one of those areas that was previously not recognized as critical but is becoming more so.
Take, for example, the gallon glass bottles used to pack, store, ship, and deliver clean process chemicals like photoresist, etchants, precursors, dielectrics, and more. For years, these were suitable and cost-effective vessels for the task at hand. However, with today’s fabrication processes using more chemistries than ever – in some cases up to 20 different types – transporting these often volatile and caustic formulations while also maintaining their purity is vital to the manufacturing process. This paper looks at the challenges posed by relying on traditional glass bottles, alternatives that have been explored, and finally a viable solution to address these challenges.
CHALLENGES WITH GLASS
Fab and operator safety, cost, sustainability, and impact on device yields are key manufacturing concerns that must be considered in the storage, transport, and delivery of clean chemicals. Unfortunately, glass bottles, the current solution, pose challenges for all of these. In general, issues with glass can be categorized according to safety, flexibility, and integrity challenges.
Safety challenges include bottle breakage, spills, and leaks from inadequate sealing mechanisms, as well as the environmental impact that results. Flexibility challenges stem from today’s advanced fabs.
It is difficult to find bottles that offer a misconnect option to avoid human error. Integrity challenges refer to anything that can cause possible contamination of the chemistry that leads to wafer and device defects. This includes the leaching of trace metals, particle contamination, extractable organics, and moisture and oxidation. Let’s look at the root causes of some of these.