Thermal and stress analysis of semiconductor wafers in a rapid thermal processing oven

Abstract

This paper describes studies of heat transfer in a rapid thermal processing-type oven used for several semiconductor wafer processes. These processes include 1) rapid thermal annealing, 2) thermal gradient zone melting, and 3) lateral epitaxial growth over oxide. The heat transfer studies include the measurement of convective heat transfer in a similar apparatus, and the development of a numerical model that incorporates radiative and convective heat transfer. Thermal stresses that are induced in silicon wafers are calculated and compared to the yield stress of silicon at the appropriate temperature and strain rate. Some methods of improving the temperature uniformity and reducing thermal stresses in the wafers are discussed.

A lamp thermoelectricity based integrated bake/chill system for photoresist processing

“…The view-factor model used here is adapted from those of Norman [26] and Lord [32] which exhibit good agreement between simulation results and experimental data [32,33]. The spectral radiosity of each surface element i is denoted as J i,k and given by…”

Optimization of rapid thermal processing for uniform temperature distribution on wafer surface

“…Radiation is the dominant heat transfer mode in RTP, which occurs directly from the lamps to the wafer or one part on the wafer to another part on the wafer through reflection. The surfaces of the wafer and the chamber wall are assumed to be gray, diffuse [2,6], opaque [9]. Radiative heat transfer can be easily calculated with view factor, irradiation, radiosity and assumptions such as gray surfaces whose emissivity and absorptivity are independent of wavelength of radiation spectrum, and diffuse surfaces.…”

“…Kim et al [1] constructed an RTP chamber with linear type tungsten-halogen lamps as a heating source and analyzed the capability of that system, which consists of ion implanting, annealing and oxidization process. Lord [2] predicted the wafer temperature and thermal stress by considering radiative and convective heat transfer, and compared the results with the experimental data. He concluded that convective heat transfer did affect wafer temperature uniformity in atmospheric pressure condition.…”

Micro-Raman study of stress distribution generated in silicon during proximity rapid thermal diffusion

“…One of the main challenges in rapid thermal processing lies in minimising the development of thermal stress in the wafer [9]. Usually, the wafer is heated on both sides within the RTP using tungsten halogen lamps.…”

“…Lord [9] modelled the wafer temperature and stress distribution for unpatterned silicon wafers during RTP, using a simple twodimensional (2-D) reactor scale model and assuming the temperature profiles to be axisymmetric. Erofeev et al [11] modelled the three-dimensional (3-D) temperature and stress distributions of wafers.…”