PURPOSE To differentiate between keratoconus and contact lens-related corneal warpage by combining focal change patterns in anterior corneal topography, pachymetry, and epithelial thickness maps. METHODS Pachymetry and epithelial thickness maps of normal, keratoconus, and warpage, and forme fruste keratoconus (FFK) eyes were obtained from a Fourier-domain optical coherence tomography (OCT). E...

Purpose. To evaluate the difference in biomechanical properties between contact lens induced corneal warpage and normal and keratoconic eyes. Method. Prospective observational case control study, where 94 eyes of 47 warpage suspicious and 46 eyes of 23 keratoconic patients were included. Warpage suspected cases were followed until a definite diagnosis was made (warpage, normal, or keratoconus)....

The main objective of writing review on warpage optimization of injection molded plastic part is to investigate the optimization techniques used for minimization of warpage by optimizing process parameters during injection molding. Highly complex design of plastic products now a days demands dimensional accuracy and good surface finish. As the injection molded part cools, uneven distribution of...

Wafers warp. It is important to minimize warpage in order to achieve optimal die yield and potentially prevent future device failure. Although the word warpage is widely used in the literature to represent wafer bow (convex or concave shape), in the real world wafers are often seen into warp into saddle shapes. This complicates the characterization of both the sources of and solutions to warpag...

Wafer warpage is common in microelectronics processing. Warped wafers can affect device performance, reliability and linewidth control in various processing steps. We proposed in this paper an in-situ fault detection technique for wafer warpage in lithography. Early detection will minimize cost and processing time. Based on first principle thermal modeling, we are able to detect warpage fault f...

Far infrared Fizeau interferometry (FIFI) and shadow moiré with enhanced sensitivity (SMES) are developed for real time warpage measurement of microelectronics devices. The methods are implemented in a compact apparatus that is based on a computer controlled environmental chamber. The apparatus combines the two methods to provide unique capabilities of thermally induced warpage measurement with...

The presence of thermal mismatch between different materials of plastic IC packages was found to cause reliability and moldability issues such as delamination and warpage phenomenon. Delamination and warpage between the mold compound and die attach adhesive material were evaluated for Quad Flat No-lead (QFN) package. Evaluation was conducted on two set of different materials combination of epox...

In this paper, both experimental and modeling works were resorted to analyze the warpage and wire sweep of QFN molded strip. The effect of QFN package size was investigated to provide the relation between warpage and metal to mold compound ratio. Design guideline for optimum metal to mold compound ratio has been obtained. Nonlinear large deformation of finite element analysis has been performed...

Warpage is known to be one of the primary molding issues during assembly of QFN package. It affects the package sawing process, and cause reliability issues. The main cause of warpage of area array packages is the coefficient thermal expansion (CTE) mismatch between the moulding compound and other components inside the package. The objective of this study is to investigate the warpage induced o...

The main objective of this paper is to predict the warpage of a circular injection molded part based on different processing parameters. The selected part is used as spacers in automotive, transmission, and industrial power generation industries. The second goal is facilitating the setup of injection molding machine without (any) need for trial and error and reducing the setup time. To meet the...