Photoluminescence metrology for LED characterization in high volume manufacturing

In this paper we will review typical applications of photoluminescence (PL) metrology in high volume LED manufacturing environments. PL is a well-established method for analysis of semiconductor properties. The technique is non-contact, non-destructive and rapid. We will describe the principles of the measurement and review PL data from LED process wafers. We will discuss how PL measurement results like peak wavelength, dominant wavelength and PL intensity are obtained. We will summarize the accuracy, precision, stability and other considerations of the measurement. Finally, metrology considerations for manufacturing LEDs on large diameter substrates, including the possibility of 8" silicon substrates, will be presented.