Non-contact apparatus and methods for evaluating at least one of the DC (or RF) dielectric constant, the hardness, and Young's Modulus of a dielectric material on a microelectronic workpiece under process and for generating a correlation factor that relates a measured IR spectrum to at least one of the dielectric constant, the hardness, and Young's Modulus of the dielectric material. A specific example of a method comprises measuring a thickness of the dielectric material on the process workpiece, irradiating the process workpiece with an IR source, and collecting and measuring an IR spectrum from the process workpiece. The measured thickness and at least a portion of the measured IR spectrum from the process workpiece are used with the correlation factor to determine at least one of the dielectric constant, the hardness, and Young's Modulus of the dielectric material. The determined value from the correlation factor is then stored and/or displayed.