Photoresist deposition without spinning

A technique for resist deposition using a novel fluid ejection method is presented in this paper. An ejector has been developed to deposit photoresist on silicon wafers without spinning. Drop-on-demand coating of the wafer reduces waste and the cost of coating wafers. Shipley 1400-21, 1400-27, 1805, and 1813 resists were used to coat sample 3- and 4-in wafers. Later, these wafers were exposed and developed. The deposited resist film was 3.5 /spl mu/m thick and had a surface roughness of about 0.2 /spl mu/m. The ultimate goal is to deposit resist films with a thickness of the order of 0.5 /spl mu/m and a surface roughness of the order of 30 /spl Aring/, which is currently achieved for 200-mm silicon wafers by using a spinning method. Such goals can be attained by using micromachined multiple ejectors or with better control over the deposition environment. In the micromachined configuration, thousands of ejectors are made into a silicon die, as presented by Percin et al. (2002), and thus allow for a full coating of a wafer in a few seconds. Coating in a clean environment will allow the lithography of circuits for microelectronic applications. Other potential applications for the technology in the semiconductor manufacturing are in deposition of low-k materials, wafer cleaning, manufacturing of organic LEDs and organic FETs, direct lithography, nanolithography, and coating for hard-disk drives.     

Mesoaxial complete syndactyly and synostosis with hypoplastic thumbs: an unusual combination or homozygous expression of syndactyly type I?

Syndactyly type I is an autosomal dominant condition with complete or partial webbing between the third and fourth fingers or the second and third toes or both. We report here a previously undescribed phenotype of severe mesoaxial syndactyly and synostosis in patients born to affected parents. The characteristic features of these severe cases are (1) complete syndactyly and synostosis of the third and fourth fingers; (2) severe bone reduction in the proximal phalanges of the same fingers; (3) hypoplasia of the thumbs and halluces; (4) aplasia/hypoplasia of the middle phalanges of the second and fifth fingers; and (5) complete or partial soft tissue syndactyly of the toes. We report on three offspring with this phenotype from two different branches of a syndactyly type I family, suggesting that they may be homozygous for this condition. SSCP and linkage analysis indicated that neither HOXD13 nor other relevant genes in the chromosome 2q31 region was responsible for this phenotype.     

Preparation and characterization of P2FAn/PVDF composite cation-exchange membranes for the removal of Cr(III) and Cu(II) by Donnan dialysis

In this work, poly(2-fluoroaniline) (P2FAn) was chemically synthesized with different dopant anions such as p-toluenesulfonate (PTS), 1,3 (6 or 7)-naphthalene trisulfonic acid (NSA), o-aminobenzen sulfonic acid (ABS), sodium dodecyl sulfate (SDS). The P2FAn/PVDF composite cation-exchange membranes were obtained from prepared poly(2-fluoroaniline) by casting method. These membranes were used for the removal of chromium (III) and copper (II) ions from aqueous solution with Donnan dialysis (DD) experiments. The change of surface morphologies of the P2FAn/PVDF composite cation-exchange membranes were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The membrane thickness and their ion-exchange capacities were also measured. The flux values (J) and recovery factor (RF) of chromium (III) and copper (II) were obtained. The flux value of Cu(II) ion was higher than Cr(III) for all of composite membranes because of the hydration volume.     

Fine Bubble‐based CO2 Capture Mediated by Triethanolamine Coupled to Whole Cell Biotransformation

Carbon capture technology can be set up in combination with biocatalysis to utilize the bound CO₂ as substrate in the Kolbe‐Schmitt like enzymatic reaction. The exemplary whole cell biotransformation of catechol to 2,3‐dihydroxybenzoic acid in a triethanolamine‐mediated multiphase system shows increased equilibrium conversion. Apart from the beneficial thermodynamics, the inherent fluid properties of triethanolamine is enabling easy application of CO₂ fine bubbles as highly efficient gassing method to minimize the CO₂ demand and CO₂ emissions.     

Acoustically actuated flextensional Si/sub x/N/sub y/ and single-crystal silicon 2-D micromachined ejector arrays

We propose using two-dimensional (2-D) micromachined droplet ejector arrays for environmentally benign deposition of photoresist and other spin-on materials, such as low-k and high-k dielectrics used in IC manufacturing. Direct deposition of these chemicals will reduce waste as well as production cost. The proposed device does not harm heat or pressure sensitive fluids and they are chemically compatible with the materials used in IC manufacturing. Each element of the 2-D ejector array consists of a flexurally vibrating circular membrane on one face of a cylindrical fluid reservoir. The membrane has an orifice at the center. A piezoelectric transducer generating ultrasonic waves, located at the open face of the reservoir, actuates the membranes. As a result of this actuation, droplets are fired through the membrane orifice. Ejector arrays were built with either Si/sub x/N/sub y/ or single-crystal silicon membranes using two different fabrication processes. We show that single-crystal silicon membranes are more uniform in their thickness and material quality than those of Si/sub x/N/sub y/ membranes. The single-crystal silicon membrane-based devices showed thickness and material uniformity across all the membranes of an array. This improvement eliminated nonuniform membrane resonance frequencies across an array as observed with Si/sub x/N/sub y/ membrane-based devices. Therefore, it should be possible to repeatably build devices and to predict their dynamic characteristics. Using the fabricated devices, we demonstrated water ejection at 470 kHz, 1.24 MHz, and 2.26 MHz. The corresponding droplet diameters were 6.5, 5, and 3.5 /spl mu/m, respectively.