Axus Technology delivers and supports a wide array of backgrinding tools from several OEMs. One of these tools, the Strasbaugh 7AA grinder, has proven to be a durable industry workhorse and continues to be a versatile and exceptionally economical tool. Aside from being one of the first backgrinding platforms delivered to the semiconductor industry, the coaxial grinding wheel design, with a coarse and fine wheels operating on the same spindle, make it remarkably easy to align and maintain.
Axus Technology delivers completely rebuilt tools in a variety of configurations. Tools can be configured for manual or automatic loading, expanded recipe and data storage, and Bernoulli-chuck wafer handling along with other performance enhancements. The 7AA, initially designed for 3” to 150mm substrates, can also be configured by Axus Technology for use with 200mm and larger substrates. It’s proven to be a very durable and flexible process tool.
Even with all of that, two recent upgrades will increase the longevity and utility of the 7AA platform. The introduction of a replacement LCD monitor to replace the original single color CRT makes the tool easier for operators to manage and addresses concerns about the ongoing availability of the CRT. The LCD monitor is a simple drop-in replacement that includes the mounting interconnect, mounting hardware, and bezel. This addresses a primary concern about ongoing tool support and provides a more useful operator interface.
Even more significant is the In Line Gauging (IPG) upgrade for the 7AA. The gauging upgrade provides accurate real-time measurement of the substrate thickness during grind. While the 7AA thickness control algorithm is a clever method for managing thickness of production lots of material, as a post-process measurement as a post process measurement is requires several “send ahead” wafers in order to stabilize the thickness control. The post-process measurement format is dependent on stable grind wheel wear rates and uniform grinding rates. This has proven to be quite limiting for users of manual load tools, as well as when grinding small lots of material. The post-process measurement format can also be limiting for applications with more hard and more challenging substrates where cycle times may be long and wheel wear rates are high. The real-time measurement delivered by the IPG upgrade eliminates the need for send ahead wafers and removing the wheel-wear rate as a variable. And, since the IPG measurement occurs can be set up to occur near the center of the grind chuck, it can be used in very small substrates. The IPG upgrade has been installed for use with standard wafer sizes, as well as with small ceramics, most notably for grinding sapphire and SiC substrates. The thickness accuracy and control is specified at +/- 2um, with nearly all installations achieving +/-1um repeatability.
Whether for a 7AA that is currently in use or there is a need to add an exceptionally accurate and economical substrate thinning tool, the 7AA and IPG upgrade deliver process performance -- for development or production applications -- that is generally better than can be achieved on new backgrinding tools. For more information about the 7AA and upgrades, or for information about any other backgrinding equipment, please contact us.