Vacuum load-lock

There are several types of deposition chamber configurations (Fig. 2). The batch-type system is the most commonly used, but the requirement that the system be returned or let-up to ambient pressure on each cycle can pose problems in obtaining a reproducible processing environment. The load-lock system and the in-line system allows the deposition chamber to be kept under vacuum at all times and the substrates introduced and removed through... 

Fig. 2. Vacuum processing chamber configuration (a) batch coater (b) load-lock coater (c) in-line coater (d) cluster tool (e) roU coater (batch) and (f) roU coater (air-to-air), [[ccsq]] represents the isolation valve with transfer tooling [[artl]], the motion of fixturing and [[art2]], the access door.

Commercial spectrometers are usually bakeable, can reach ultrahigh-vacuum pressures of better than 10" Torr, and have fast-entry load-lock systems for inserting samples. The reason for the ultrahigh-vacuum design, which increases cost considerably, is that reactive surfaces, e.g., clean metals, contaminate rapidly in poor vacuum (1 atomic layer in 1 s at 10 Torr). If the purpose of the spectrometer is to always look at as-inserted samples, which are already contaminated, or to examine rather unreactive surfaces (e.g., polymers) vacuum conditions can be relaxed considerably. 

Electrocatalytic activity of supported metal particles has been investigated on surfaces prepared in an ultrahigh vacuum (UHV) molecular beam epitaxy system (DCA Instruments) modified to allow high throughput (parallel) synthesis of thin-film materials [Guerin and Hayden, 2006]. The system is shown in Fig. 16.1, and consisted of two physical vapor deposition (PVD) chambers, a sputtering chamber, and a surface characterization chamber (CC), all interconnected by a transfer chamber (TC). The entire system was maintained at UHV, with a base pressure of 10 °mbar. Sample access was achieved through a load lock, and samples could be transferred... 

By using a multichamber system [129], exchange of residual gases between successive depositions will be strongly decreased, and very sharp interfaces can be made. Furthermore, the use of a load-lock system ensures high quality of the background vacuum, and thus low levels of contaminants in the bulk layers. Multichamber reactor systems have been used for the fabrication of solar cells, and considerable improvements in energy conversion efficiency have been achieved [130, 131]. 

Figure 6. Plan of the target preparation facilities consisting of UHV preparation chamber (a), (reactive) ion etching chamber (b), ion etching gun (c), laser (d), photon detector (e), transfer arms (f), Auger system for surface analysis (g), sample manipulator and annealing facility (h), load lock and optical microscope for viewing sample (i), evaporator (j), transmission diffractometer (k), and vacuum tank for main spectrometer (1).

Figure 19-2. Schematic overview of the type of apparatus used to investigate the desorption of ions and neutral species induced by electron impact on thin molecular and bio-organic films. In the case of thin DNA films, they are formed outside vacuum by lyophilization on a metal substrate or as a self-assembled layer. The films are placed on the multi-sample holder in the load-lock chamber. From there, they can be transferred one by one to the main chamber for analysis...

The metal-on-polymer interface has been the most studied Interface as metals can conveniently be deposited by evaporation in situ 1n a controllable fashion in a UHV system (26-33). In the case of polyimide, Cu and Cr have been the most studied metals but other metals including N1, Co, Al, Au, Ag, Ge, Ce, Cs, and Si have been studied. The best experimental arrangement includes a UHV system with a load lock Introduction chamber, a preparation chamber with evaporators, heating capabilities, etc., and a separate analysis chamber. All the chambers are separated by gate valves and the samples are transferred between chambers under vacuum. Alternative metal deposition sources such as organometall1c chemical vapor deposition are promising and such techniques possibly can lead to different interface formation than obtained by metal evaporation(34). 

Fig. 11.5. Sketch of the MAJESTIX setup. The vacuum system is divided into a preparation chamber and a particle-beam chamber, separated by a gate valve. The preparation chamber is also used as load lock. The main components in the particle-beam chamber are the ion gun system, comprising a Wien filter and deceleration...

The polymer films were solvent cast on stainless steel substrates and air dried at 22C their final thickness was about 0.001 mn. After insertion into the ultra-high vacuum chamber througji a load-lock chamber, the polymers were warmed to temperatures above their respective glass transition temperatures for the time needed to remove the remaining solvent from the bulk of the film. 

A schematic of a MALDI-TOF-MS instrument is depicted in Figure 11.2b. Samples, consisting of a few microlitres of analyte solution (with or without matrix), are deposited on a MALDI target (Figure 11.2a). After the solvent has evaporated the sample plate, carrying the solidified samples, is introduced into the MALDI ionization chamber via load-lock. The ionization process takes place in a high-vacuum chamber to which the plate is introduced via a prechamber kept at a pressure lower than atmospheric. Analyte ions are then accelerated as they are formed and pumped into the TOF analyzer, where they are separated based on their mass-to-charge ratio. 

On-chip Reaction and Analysis. To prove the principle of the monitoring window , the Schiff base formation reaction between 2 and 4 in ethanol (Scheme 11.1) was carried out using the MALDI-chip device equipped with the chip of Figure 11.9. The chip placed on the MALDI sample plate was introduced into the vacuum chamber by load-lock. The first MALDI-TOF mass spectrum was acquired as soon as the plate reached the right spot in the chamber. The analysis started after about 1 min. Ions were extracted from the... 

Whenever possible, more rapid turnaround time, the absence of load locks, the reduced maintenance cost associated with the avoidance of vacuum systems, and the ease of incorporation into continuous processing systems, all combine to make atmospheric pressure chemical vapor deposition an attractive technique. In general, removal of reaction co-products is accomplished by utilization of a large excess of carrier gas (typically argon or nitrogen). Additionally, it may be noted that the thermal oxidation... 

The wet disks are immediately immersed into the vapor of refluxing isopropanol. Once they reach the reflux temperature, as noted by a reduction in the rate of alcohol condensation on the disks, they are removed into the room air where they rapidly become dry and slowly cool to room temperature. At this point, the disks are individually weighed to the nearest 0.1 mg. The disks are then loaded into a metal tray with large circular regions on their bottom faces exposed and the tray placed in the load lock of a vacuum chamber. The load lock is pumped to about 10 torr and then the tray is translated into the chamber and the load lock sealed off from the chamber. The chamber is pumped to about 10 torr with a cryopump. The major residual gas is water from the rotatable rubber seal used between the evacuated space in the chamber and the water flow path into and out of the rotatable copper crucible mentioned below. Titanium vapor is sublimed from a Ti ingot by bombardment with about 8 keV electrons while the periphery of the ingot is cooled by sparse physical contacts with the water-cooled copper crucible in which it rests. The Ti vapor condenses in the line of sight from the source onto the exposed bottoms of the disks. The thickness of the deposited titanium, is monitored by a calibrated quartz crystal balance close to the quartz disks. Typically (iji 5 x 10 cm. 

Insert the holder in the load lock of the mass spectrometer and pump it down until the required vacuum is reached. 

Fig. 3.12 Sample preparation setup consisting of a rotary, linear stainless z-slide transfer manipulator attached to a UHV chamber cross. On the manipulator tip customized sample holders are fixed and can be moved between the positions ( i and 2). The samples are prepared in a load lock, equipped with a differentially pumping system and separated by means of a pneumatic vacuum gate for details see text...

Deposition system, cluster-tool (semiconductor processing) A load-lock vacuum system that has random access to several processing modules from the loading/transfer chamber. 

Deposition system, in-line A series of sequential vacuum modules beginning and ending with load-lock chambers, that allows the substrate to enter at one end and exit at the other without reversing direction. 

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