Laser-drilled hole

Osmotic Pressure Controlled Oral Tablets. Alza Corp. has developed a system that is dependent on osmotic pressure developed within a tablet. The core of the tablet is the water-soluble dmg encapsulated in a hydrophobic, semipermeable membrane. Water enters the tablet through the membrane and dissolves the dmg creating a greater osmotic pressure within the tablet. The dmg solution exits at a zero-order rate through a laser drilled hole in the membrane. Should the dmg itself be unable to provide sufficient osmotic pressure to create the necessary pressure gradient, other water-soluble salts or a layer of polymer can be added to the dmg layer. The polymer swells and pushes the dmg solution through the orifice in what is known as a push-pull system (Fig. 3). The exhausted dmg unit then passes out of the body in fecal matter. 

Pills can operate as osmotic "pumps" if they have miniscule laser-drilled holes in them. The pill coating is selective in that water from the body is allowed to enter to displace the drug at a constant rate. 

Figure 4. A photograph of a pattern of laser drilled holes in steel representing the number 5383158068. Abo shown is a Va" stamped digit for the purpose of size comparison.

Figure 5 (A) lA-CE of IgE in serum using multiple capillaries in bundles, (B) lA-CE of IgE in serum using solid glass rod with laser drilled holes.

Figure 23.1. Two types of light-pipe used in the GC/FT-IR interface (a) with effluent from the GC column passing through a fitting (b) with GC effluent passing through a laser-drilled hole in the boro-silicate tube from which the light-pipe is constructed.

Micro-jet arrays are usually associated with lower energy consumption rates than sprays generated by the special (HAGO) nozzle for the same flow rate. The liquid was pushed through a 0.5 mm stainless steel orifice plate to form the jets. The holes in the plate were laser drilled and were arranged in a circular pattern giving a radial... 

The theory and instrumentation of Fourier transform mass spectrometry (FTMS) have been discussed extensively in this book and elsewhere [21-23]. All experiments were performed on a Nicolet prototype FTMS-1000 Fourier transform mass spectrometer previously described in detail [24] and equipped with a 5.2 cm cubic trapping cell situated between the poles of a Varian 15 in. electromagnet maintained at 0.85 T. The cell was constructed in our laboratory and utilizes two 80 transmittance stainless steel screens as the transmitter plates. This permits irradiation with a 2.5 kW Hg-Xe arc lamp, used in conjunction with a Schoeffel 0.25 m monochromator set for 10 nm resolution. Metal ions are generated by focusing the beam of a Quanta Ray Nd YAG laser (either the fundamental line at 1064 nm or the frequency doubled line at 532 nm) into the center-drilled hole (1 mm) of a high-purity rod of the appropriate metal supported on the transmitter screen nearest to the laser. The laser ionization technique for generating metal ions has been outlined elsewhere [25]-... 

FIGURE 2.9 SEM micrographs of micromachined holes in borosilicate glass using three different methods, (a) Ultrasonically drilled hole hole diameter, 500 pm. (b) Laser machined hole hole diameter, 300 pm. (c) Sand-blasted hole hole diameter 1000 pm [104], Reprinted with permission from the Institute of Physics Publishing. 

In order to provide access holes on fused quartz cover chips, laser drilling [151,152,828,1006] or ultrasonic drilling [349,1041] have been used. In order to remove particulates caused by drilling, the drilled quartz plate was rinsed in 0.5% HF for 5-10 min in an ultrasonic bath [153,658]. However, in some cases no drilling was performed, with the end of the channel protruding out of the coverslip [148],... 

A (100) silicon wafer 10 is anisotropically etched to form hollows 11 having sloped sides 15. A plurality of via holes are etched or laser drilled through the floor 17 of each hollow. Next, the wafer is oxidized to coat its surfaces with a first insulator of SiC>2. A refractory conductor is deposited within the vias to form conductive conduits. A perspective view of a single hollow is shown below. 

The laser drilling based marking system is commercially feasible and could be fully automated for a production procedure. It could also be used to tag individual items. If desired, the holes could be fully hidden by a treatment of the surface after drilling. Further work is in progress to evaluate the potential... 

Compared with conventional photolithography, laser drilling is a dry process and keeps the surface of polyimide gate dielectric layer away from water, etching solution, or other solvent, which often degrade the polyimide surface. We have confirmed that the electronic performance of transistors with laser via holes is identical with that without laser via holes. 

Laser cutting is a fast growing process. The laser can act as a materials eliminator. Concentrating its energy on a small spot, it literally vaporizes the material in its path. If the workpiece is held stationary, the laser drills a hole. If the piece is moved, it slits the material. The induced heat is so intense and the action of the laser is so fast that only little heating of the adjacent areas of the piece takes place. 

To be referred to next is the most modem diamond anvU type, generating pressures of order of 10 -100 GPa. The cell illustrated in Figure 6(e) consists of two gem diamonds with optically flat surfaces, between which a sample confined in a drilled hole of a thin metal gasket is sandwiched. To attain isostatic compression an inert gas or an organic liquid, like a 4 1 volume mixture of methanol and ethanol, is contained with the sample. The generated pressure is measured directly from the pressure shift of the fluorescence line of mby powder mixed with the sample. Temperatures to 5000 K can be obtained by laser heating. The quantity of sample confined in a typically 0.1-mm-wide hole is extremely small, just a few microcrystals. At present, research has focused on in situ observations using X-ray and other optical methods, rather... 

Matrix-sustained release tablets may present additional problems since they tend to stick to the side walls of the vessel, giving a reduction in the surface area exposed and the use of the paddle may destroy the discreteness of the dosage form. In such instances, the choice of apparatus is critical. Osmotic pump devices where a microscopic orifice is laser-drilled into the surface of the tablet coating are not amenable to testing by Apparatus 1-4 as the tablet may lie in such an orientation as to obscure the hole. In this case, drug release is determined by USP Apparatus 7 with the tablet glued onto the end of a reciprocating rod. 

In TSV, vertical micro through holes (vias) are chemically etched, mechanically drilled or laser drilled in the silicon die at the wafer level, then made electrically conductive by plating or vapor depositing metal conductors. The sidewalls of the vias, however, must first be insulated from the silicon. A dielectric film overlaid with conductive metal may be applied to the sidewalls or the exposed silicon may first be oxidized to isolate it from subsequent metallization. Connections within the chips are generally made between bond pads on one face of the die to a land on the opposite side. 

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