Container for precursors used in deposition processes

#The present invention relates to new and useful containers for precursor materials used as source materials in atomic layer deposition (ALD) or metalorganic chemical vapor deposition (MOCVD) processes and to methods related thereto.

#Atomic layer deposition (ALD) is an enabling technology for next generation conductor barrier layers, high-k gate dielectric layers, high-k capacitance layers, capping layers, and metallic gate electrodes in silicon wafer processes. ALD has also been applied in other electronics industries, such as flat panel display, compound semiconductor, magnetic and optical storage, solar cell, nanotechnology and nano materials. ALD is used to build ultra thin and highly conformal layers of metal, oxide, nitride, and others up to one monolayer at a time in a cyclic deposition process. Oxides and nitrides of many main group metal elements and transition metal elements, such as aluminum, barium, cerium, dysprosium, hafnium, lanthanum, niobium, silicon, strontium, tantalum, titanium, tungsten, yttrium, zinc and zirconium have been produced by ALD processes using oxidation or nitridation reactions. Pure metallic layers, such as Ru, Cu, Ti, Ta, W, and others may also be deposited using ALD processes through reduction or combustion reactions.

#A typical ALD process is based on sequential applications of at least two precursors to the substrate surface with each pulse of precursor separated by a purge. Each application of a precursor is intended to result in up to a single monolayer of material being deposited on the surface. These monolayers are formed because of the self-terminating surface reactions between the precursors and surface. In other words, reaction between the precursor and the surface should proceed until no further surface sites are available for reaction. Excess precursor will not react with same type of precursor that has already reacted at the surface site and the excess precursor is then purged from the deposition chamber. Following the purge, the second precursor is introduced and reacts with the first precursor on the surface. Any excess second precursor is purged after surface saturation. Each precursor pulse and purge sequence comprises one ALD half-cycle that theoretically results in up to a single additional monolayer of material. Because of the self-terminating nature of the process, even if more precursor molecules arrive at the surface, no further reactions will occur. It is this self-terminating characteristic that provides for high uniformity, conformality and precise thickness control when using ALD processes.

#FIG. 1 is a cut away plan view of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.

#FIG. 2 is a three dimensional view of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.

#FIG. 3 is a three dimensional cut away view showing the interior of a container for precursor source material and solvent rinse in accordance with one embodiment of the present invention.

#The present invention will be described in detail with reference to the drawing figures. In particular, FIG. 1, is a schematic view of the container system according to a first embodiment of the present invention, and shows a container system 100, that holds both a precursor source solution and a solvent rinse separately. The system 100, includes a container 10, having two separate chambers defined by an outer wall 12, and an inner wall 14. The container 10, can be of any desirable shape or size, but preferably is cylindrical in shape and sized to fit within the existing space of a fabrication area. For example, the outer wall 12, may be defined by a first cylinder of a first diameter and the inner wall 14, may be defined by a second cylinder having a second diameter smaller than that of the first cylinder, such that the second cylinder fits concentrically or in an offset manner within the first cylinder. The two cylinders are welded to two planer circular disks having a diameter equal to the diameter of the first cylinder and arranged so as to provide a top 16, and bottom 18, for the container 10.

#By constructing the container 10, in the manner described above, two chambers are formed. In FIG. 1, the innermost chamber is used to contain a liquid precursor or precursor solution 20 (hereinafter referred to as precursor solution 20) and the outermost chamber contains solvent rinse 25. The volume ratio of precursor solvent rinse to precursor solution can range from ten percent (10%) up to one hundred percent (100%) depending on the desired manufacturing application. It is also possible to reverse the location of the solutions, i.e. the precursor solution can be in the outermost chamber and the solvent rinse in the innermost chamber.

#Either of the precursor solution 20, or the solvent rinse 25, can be delivered to a DLI system 30, through the use of dip tubes and the maintenance of head pressure within the two chambers of the container 10. In particular, a precursor solution dip tube 40, equipped with an optional particle filter 42, is located in the inner chamber of the container 10, submerged within the precursor solution 20. Further, a rinse solvent dip tube 50, equipped with an optional particle filter 52, is located in the outer chamber of container 10, and submerged within the rinse solvent 25. The precursor solution dip tube 40, and the rinse solvent dip tube 50, each provide their respective solutions to the DLI system 30, through appropriate piping and valves. In particular, a three way valve system can be employed so that the supply of appropriate solution can be switched as needed for processing, i.e. precursor solution 20, will be supplied to the DLI 30, during a deposition stage, and rinse solvent 25, will be supplied to the DLI 30, during a cleaning stage. Optional check valves can be included for added control and to prevent back flow to the container 10. The dip tubes, connection piping and valves can be constructed of any inert material, preferably electro-polished stainless steel.