This paper presents the application of ripple pyrometry on AG Associates Integra systems which are three phase powered and multi-zone controlled rapid thermal CVD cluster tools. Two types of sensor configurations were explored for optimum emissivity compensated temperature measurement performance. It was found that it is very difficult to measure temperature when a two sensor configuration is used due primarily to the chamber and reflector architecture. Good temperature measurement was obtained at high temperatures when zone ratios between the wafer and lamp sensors were aligned. It was also found that the temperature signal to noise ratio is very sensitive to ripple quality and zone ratio alignment accuracy.

A two-channel optical-fiber pyrometry technique for simultaneous measurement of thermal radiance and emittance was used to measure and control the temperature of silicon wafers heated by quartz-halogen-tungsten lamps in various rapid-thermal processors, including an A.G. Associates Heatpulse. The ripple method dynamically determines emittances by sensing time-dependent components in radiation from the lamps and radiation reflected by the wafer surface. Wafers were coated with films of various textures and patterns to test the technique over a range of surface emittances spanning about an order of magnitude. Temperature accuracies of at least ±5°C are achievable from 650°C to 1050°C, and above, for pyrometry at lμm wavelength.

A novel wafer temperature and emissivity measurement technique for rapid thermal processing (RTP) is presented. The ‘Ripple Technique’ takes advantage of heating lamp AC ripple as the signature of the reflected component of the radiation from the wafer surface. This application of Optical Fiber Thermometry (OFT) allows high speed measurement of wafer surface temperatures and emissivities. This ‘Ripple Technique’ is discussed in theoretical and practical terms with wafer data presented. Results of both temperature and emissivity measurements are presented for RTP conditions with bare silicon wafers and filmed wafers.