Flexibility between lab and fab
As epitaxial structures become more complex, quality control adopts lab methods.
BY TIM GORTER AND LARS GRIEGER, MALVERN PANALYTICAL
COMPOUND SEMICONDUCTOR functionality is all about the layer structure. But unlike a cake, it’s rare that you wish to slice up your wafer to see what is going on inside.
Fortunately, though, in this instance you can turn to metrology technologies, such as X-ray diffractometry (XRD), to generate accurate and precise structural metrology in a non-destructive manner. Here, advanced capabilities beyond the rocking curves are becoming ever more important for the production of epitaxial wafers.
Production of compound semiconductor wafers continues to rise, as our society seeks to unlock the potential of these materials that offer significant sustainability benefits. If you are a regular reader of this magazine, you will know all too well about the energy savings that come from widespread deployment of compound semiconductors in LEDs or power converters. Increasing manufacturing excellence of compound semiconductor lowers cost, so that these chips can feature in even more electronic products shipped and sold around the globe. The epitaxial growth these devices is monitored by XRD techniques – but what does the maturation of the compound semiconductor industry mean for analytical XRD instruments and those who use them?
The infrastructure for metrology tools located at R&D sites are different compared to fabrication sites
Method transfer from lab to fab
A significant difference between a typical fab and the majority of research labs is the performance criteria for the equipment. Often the difference comes from the jump in the accompanying quality benchmarks that must be met. Almost all CS fabs maintain a cleanroom environment in line with ISO and federal classifications for their epitaxial department. Consequently, fabs need to adopt the latest Semiconductor Equipment and Manufacturing International (SEMI) standards to ensure that production lines comply with ISO cleanroom practices and enable their yield targets.
In parallel, automation is increasingly widespread, justified by the grown volume in these markets. It is a valuable asset in semiconductor production, with automated solutions reducing the need for human involvement and cutting contamination.
Of course, a significant upfront investment may be needed to set up a fab with the appropriate instruments, technologies, and quality controls to ensure that it runs smoothly – and the financial outlay can cause headaches of its own.