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Gauge Repeatability and Reproducibility (Gauge R&R , G.R.R) is of great importance for checking measurement system precision, traditional average-range G.R.R test involves equipment variation (EV) and appraiser variation (AV), which is not appropriate for current modern automatic measurement tools. In this paper, we designed different test experiments on film thickness (THK) and critical dimension (CD) metrology and statistically analyzed different variances impact on G.R.R. From THK G.R.R experiment ANOVA analysis, it can be seen that time interval and measurement process have no significant effect on G.R.R result, and the equipment repeatability variation is the major variation source. From CD G.R.R experiment ANOVA analysis, it can be checked that, G.R.R has significant time dependence of data collection due to test wafer changed. As a conclusion, not only appraiser’s variation but also time interval has less impact on metrology G.R.R of semiconductor wafer manufacturing process.

A new optical design of a confocal double-reflector, for white LED lighting, performing uniform illumination with a specific projection angle has been presented and demonstrated. In addition, the anti-glare design with double-reflector prevents direct view of the LED, and the measured veiling luminance is much lower than that in general LED-based projection lamps.

The accuracy of ion implantation is very important in semiconductor manufacturing and will directly affect the performance of the individual devices and even the whole chip. The deviation of IMP energy, dose and angle are often encountered because of the abnormality of implant equipment or process design limit. The ion implantation energy, dose and angle information can be qualitatively and quantitatively analyzed through SIMS [2], which provides a way to diagnose the issue of ion implanter. Based on SIMS analysis results, we can judge whether ion implant results meet the requirements and whether the process design achieves the expected goal. In this paper we report a SIMS data processing method for the analysis of the deviation of ion implantation angle. A term of deviation rate was defined and the related calculation method was introduced, which is proportional to the deviation angles of the ion implanter. And then, a statistical analysis of a large number of data on deviation rates and ion implantation angles showed that the whole sampling data followed normal distribution, and thus the corresponding 3 sigma could be obtained. Using the determined 3 sigma range of the deviation rates, we can define the acceptable range for deviation rate. Further, we can use the actual deviation rate to judge if the implant equipment needs maintenance or not, or suggest the direction for improvement. The equipment's maintenance time and cost can thus be minimized. This method can be used as an early detection to find an abnormity in an ion implant tool.

A planar-exit lighting surface is not only used in the luminaires but also useful in the display backlights and other illumination systems. Most planar-exit lighting surfaces are made by edge-lit with line light source or 1-D LED array. If it is not edge-lit type, the light source can be two-dimensional, but a cavity is required. In this paper, a high-efficiency cavity providing extremely high energy transmittance with photon recycling is reported and demonstrated. The cavity contains a diffuser and the high reflectivity surfaces. The optical efficiency of the cavity is calculated by a formula with considering photon recycling. Furthermore, various kinds of diffusers are applied to change the optical transmittance as well as the light pattern. When the reflectivity of the inner wall of the lighting cavity is about 96 %, the optical efficiency of the cavity is higher than 90 % with several diffusers. The experimental measurement as well as the calculation is demonstrated in the paper.

In this paper, we demonstrate a method to calculate the phosphor particle numbers and study the relationship among phosphor particle numbers, light output and correlated color temperature (CCT) of LEDs under remote package type and dispensing package type. We also discuss the influence of the thickness and concentration of phosphors on the performance of LEDs. We compare the various thicknesses and concentrations to check the resultant CCT and the output flux, where we can see that the lumen output is almost equal as the phosphor particle numbers is similar with the CCT at 6500±200 and 5000±100 K under the remote package type.

In this paper, we propose and demonstrate a novel design to make color mixing and projection of RGB LEDs. The optical elements include a high reflective light pipe, a volume scattering diffuser and a TIR lens. The system optical efficiency is around 46 % while the color is well mixing for the cases at the CCTs of 6500K, 4500K and 3000K.

A three-terminal optical sensor by using an aluminum-doped zinc oxide (AZO)-gated Al0.2Ga0.8As /In0.2Ga0.8As high electron mobility transistor (AZO-HEMT) on a GaAs substrate is demonstrated in this report. Optical responses under illumination of different wavelengths are investigated, as compared to a conventional Au-gated HEMT device. Experimental results demonstrate that the present design is promising for tunable optical sensing applications.

In this paper, based on Monte Carlo ray tracing we simulate light extraction efficiency and directionality of the light pattern of GaN LEDs implanted with micro-pyramid structure with or without lens encapsulation. We have shown that micro-pyramid structures at some specific slanted angles in the LEDs are useful to increase effective flux utilization through enhancement of both the directionality and light extraction efficiency.

Light extraction analysis of GaN-based light-emitting diodes (LEDs) with Monte Carlo ray tracing is presented. To obtain high light extraction efficiency, periodic structures introduced on the top surface and/or on the substrate of various types of LED are simulated, including wire bonding, flip chip and Thin GaN. Micro pyramid array with an apex angle from 20° to 70° is shown to effectively improve the light extraction efficiency. In addition, for an LED encapsulated within an epoxy lens, the patterned substrate with pyramid array is found to be a more effective way to increase light extraction efficiency than the surface texture.

In this paper, as to our best knowledge, we propose and demonstrate the first precise phosphor modeling scheme to simulate the chromatic performance of white LEDs with silicate phosphors. The phosphor model is useful to accurately simulate the power ratio of the blue and yellow lights emitted by the white LEDs and is important in white LED package.

A direct or bottom LED backlight is a key concept in large area LCD displays because it does not use a light guide, is flat, and is easy to assemble. In this paper, a method of luminance management for a bottom LED backlight is proposed and demonstrated. We analytically calculate both the power consumption and brightness uniformity in function of: screen brightness, screen size, backlight thickness, transmittance of the LCD panel, reflective cavity efficiency, gain and cone angle of enhancement films, LED array configuration, and the average luminous flux and radiation pattern of a single LED. Moreover, a 42-inch LCD television with this backlight design approach is made and demonstrated. The bottom backlight incorporates an array of RGGB 4-in-1 multi-chip LEDs within a highly reflective box behind a diffuser and a dual brightness enhancement film. We predict with an accuracy of 94% the brightness uniformity and with 96% the luminance level.

A single-chip white light LED is commonly modeled by considering the phosphor coating as a homogeneous Lambertian light source. However, this approach leads to an incorrect optical simulation of phosphor-coated multi-chip LEDs due to the presence of a previously unreported spatial distribution of emission spots across the phosphor layer. We introduce "weighting" factors based on position-dependent light strength across the phosphor surface in order to improve the model accuracy. Following the modeling algorithm in the mid-field region, we have built up a precise and practical optical model by using Monte Carlo ray tracing and weighting factors. We measure the LED radiation distribution at several representative distances to test the model performance. In all cases, the accuracy is higher than 99.5% in normalized cross correlation between the simulated pattern and experimental measurement.

Light extraction efficiency of GaN-based LEDs as functions of chip dimensions, absorption coefficients and package for both conventional one and Thin-GaN are analyzed based on Monte-Carlo ray tracing.

This paper demonstrates a novel retro-reflective dome that enhances the directionality of a light emitting diode (LED) by recycling photons reflected by a textured LED die surface. A simulation model is developed to describe both the photon recycling process within the dome and the role of specific pyramid patterns on the top surface of the LED die. Advanced simulations showed that a perfectly polished surface with 100% reflectivity potentially enhances the directionality of the dome by 340%, 250%, and 240% using reflective domes with 10°, 20°, and 30° light cones, respectively. In the experiment, the directionality of the domes exhibiting surface imperfections is enhanced by approximately 160%, 150%, and 130% using 10°, 20°, and 30° light cones, respectively. By incorporating a textured top surface on the LED die, the proposed dome effectively increases the directionality of the LED light source.

— A method of calculating the luminance and luminance uniformity of a bottom LED backlight is proposed and demonstrated. Both the power consumption and brightness uniformity as a function of screen brightness, screen size, backlight thickness, transmittance of the LCD panel, reflective cavity efficiency, gain, cone angle of the enhancement films, LED array configuration, and the average luminous flux, radiation pattern, and input power of individual LEDs. Moreover, a 42-in. LCD TV using this backlight design approach was fabricated. The bottom backlight incorporates an array of RGGB 4-in-1 multi-chip LEDs within a highly reflective box behind a diffuser and a dual brightness-enhancement film. The brightness uniformity can be predicted within an accuracy of 94% and the luminance level within an accuracy of 96%.