Lowering the Cost of Ownership (COO) of Spin Process Tools

In our last BLOG we discussed the need to lower the COO of the tools of production for those who are both designing and building their chips. The issue that we attempt to address here is how does one make that happen and at the same time improve functionality permitting the customer to do things that perhaps his competitor is not even aware of as a problem.

The aspects (solid dots below) and the responses (open dots below) to COO issues are:

  • The cost of the Bill of Materials (BOM) of the tool.
    • Employee identical hardware throughout the product line to improve economy of scale.
    • Minimize non-productive hardware, sensors and interconnect complexity.
    • Do not compromise on component quality, minimize the number of components.
  • Minimize Tool Footprint
    • Stack processes where it makes sense to do so
    • Integrate wafer handling and processes to eliminate wasted space
  • Maximize Reliability (note the very same responses to minimizing BOM costs improve reliability a clear Win-Win.
    • Employee identical hardware throughout the product line to improve economy of scale. (Enables testing and long term improvement)
    • Minimize non-productive hardware, sensors and interconnect complexity. (components that are not there cannot fail)
    • Do not compromise on component quality, minimize the number of components. (The highest quality components fail less frequently)
  • Minimize consumption of materials cost. (Things like photo resist, solvents, gases, etc.)
    • Improve tool functionality while lowering BOM cost
    • Creatively work with customers to take advantage of improved tool functionality.
    • Use software to improve functionality as well as hardware. Software has zero replication cost.
  • Increase Tool Throughput
    • Provide wafer handling capability at low cost that balances process times with minimum handling overhead time. Provide smart robotics capability.

Use “Small Grain” tools. By this we mean tools that can be provided in small increments of production while at the same time minimizing COO and Investment in absolute terms. All of the above items support this Aspect.

System Granularity and Management of Change and Growth

A very important aspect of cost of ownership (COO) of tools that include spin coaters and developers (often referred to a photoresist track tools) in the back end of line (BEOL), MEMS, and patterned sapphire substrate (PSS) processing-type processing lines is one that does not appear on the COO software packages. Often referred to as “opportunity cost,” it is specifically defined as “the difference in return between an investment one makes and another that one chose not to make.” A high degree of system “granularity” enables appropriate investment as customer needs evolve. Ultimately this can substantially reduce opportunity cost. Granularity specifically relates to tools sized to the capacity need, as well as properly balanced for output in order to minimize waste. Lets look at how that works, in the context of opportunity cost.

Since opportunity cost is always a comparison of the path chosen to the path that was not chosen, we will compare two hypothetical systems whose COO on a per wafer output basis is identical, but its granularity is different. Granularity will tend to go up in integer values. Let us suppose a system whose out put is equal to one unit of capacity, (i.e., 2000 wafers per month) and another whose out put is equal to two units of capacity (i.e., 4000 wafers per month). If the need is for one unit of capacity, then if the COO is the same and the more granular system is the clear choice. If it is two units of capacity then the choices are equal. However what happens when it is three units of capacity; then four; then five? Capacity needs often develop in incremental steps over the long term instead of in immediate doublings. The investment in the “granular approach” is obviously the more appropriate forward-thinking plan. As needs eventuate, so that capacity can be adjusted to market needs at the lowest possible cost in capital spread over time.