Wafer probe

J. Frey andD. Ioannou, Materials and Devices for High-Speed and Optoelectronic Applications H. Schumacher and E. Strid, Electronic Wafer Probing Techniques D. H. Auston, Picpsecond Photoconductivity High-Speed Measurements of Devices and Materials... 

In addition to the term MEMS, categories like microoptoelectromechanical systems (MOEMS), radio-frequency MEMS (RF-MEMS), and MEMS for medical or biomedical application (BioMEMS) have been established. The market for microfabricated devices is still in its infancy and is growing with rates comparable to the first years of microelectronics. According to one market research report, the sales of microfabricated systems was 12 billion in 2004 and is expected to grow with a CAGR of 16% to 25 billion in 2009 [6]. Recent extensions of fields of application are consumer, entertainment, and homeland security. Upcoming new devices are MEMS microphones, microenergy sources, micropumps, chip coolers, and micromachined wafer probes, and this will definitely not be the end of new developments. 

The second stage of IC fabrication is wafer probe and sorting which is a test of the functionality of the wafers followed by sectioning the wafer into individual chips. The third stage is chip assembly during... 

X 300 im diode mesas were defined by chlorine-based reactive ion etching (RIE). Pd/Au (3/200 nm) and Al/Au (30/200 nm) were used as fi-GaN and n-GaN contacts, respectively. The electrical and luminescence characteristics of the diode were measured by on-wafer probing of the devices. The I-V measurements were performed with a Hewlett-Packard 4155B semiconductor parameter analyzer. Relative optical power measurements under direct current (DC) conditions were obtained from the backside emission through the sapphire substrate onto a calibrated broad area Si photodiode. The emission spectrum and the optical power emission of the LEDs were measured as a function of drive currents. All measurements were carried out at room temperature. 

Figure 6 Computer-simulated ERS spectrum (adapted from ref. 6) for the case of 1.6-MeV He probing a silicon wafer implanted with 0.9 x 10 H atoms/cm at 10 keV (mean range of ions = 1750 A, = 20°, a = 10°).

DNA microarrays, or DNA chips consist of thousands of individual DNA sequences arrayed at a high density on a single matrix, usually glass slides or quartz wafers, but sometimes on nylon substrates. Probes with known identity are used to determine complementary binding, thus allowing the analysis of gene expression, DNA sequence variation or protein levels in a highly parallel format. 

Acidity of both zeolites was investigated by adsorption of ammonia, pyridine, d3-acetonitrile and pivalonitrile ((CH3)3CCN) used as probe molecules followed by FTIR spectroscopy. All samples were activated in a form of self-supporting wafers at 450 °C or 550 °C under vacuum for 1 h prior to the adsorption of probe molecules. 

The strength of the Bronsted (BAS) and Lewis (LAS) acid sites of the pure and synthesized materials was measured by Fourier transformed infrared spectroscopy (ATI Mattson FTIR) by using pyridine as a probe molecule. Spectral bands at 1545 cm 1 and 1450 cm 1 were used to indentify BAS and LAS, respectively. Quantitative determination of BAS and LAS was calculated with the coefficients reported by Emeis [5], The measurements were performed by pressing the catalyst into self supported wafers. Thereafter, the cell with the catalyst wafer was outgassed and heated to 450°C for lh. Background spectra were recorded at 100°C. Pyridine was then adsorbed onto the catalyst for 30 min followed by desorption at 250, 350 and 450°C. Spectra were recorded at 100°C in between every temperature ramp. 

In a DNA array, gene-specific probes are created and immobilized on a chip (silicon wafer, nylon or glass array substrate). Biological samples are labeled with fluorescent dyes or radioactivity. These labeled samples are then incubated with the probes to allow hybridizations to take place in a high fidelity manner. After incubation, non-hybridized samples are washed away and spot fluorescent or radioactivity signals resulting from hybridization can be detected. 

The ir measurements were carried out with a Perkin Elmer 580 spectrometer and fused silica cell with KBr windows allowing to outgass the zeolitic wafer at a desired temperature and to introduce and further outgass a probe molecule without contact with air. 

Acidity of the PILC. Acidic properties were studied by infrared spectrometry adsorbing pyridine as probe molecule on self supported wafers prepared by pressing the PILC into thin films (15... 

Therefore, the thickness of a wafer can be deduced. Beyond this, and more importantly, the tool enables the roughness, referencing to the upper and lower probes, to be measured, which can be converted to the so-called flatness, bow, and warp. Flatness, warp, and bow are defined in the following sections. 

Fig. 13. Schematic of a wafer shape measured using a noncontact capacitance probe. The warp and bow are exaggerated. (Courtesy of ADE Corporation, Westwood, MA.)...

A schematic for the four-point probe measurements is shown in Fig. 22. For an infinite sheet wafer (film on an unbounded wafer), the sheet resistance is... 

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