Chemistry: electrical and wave energy – Processes and products – Coating – forming or etching by sputtering
Reexamination Certificate
2001-06-14
2003-07-22
McDonald, Rodney G. (Department: 1753)
Chemistry: electrical and wave energy
Processes and products
Coating, forming or etching by sputtering
C204S192150, C204S192120, C204S298260, C204S298110, C438S687000, C427S250000, C427S255230, C427S255280, C427S576000, C427S585000, C427S595000, C118S7230AN, C118S7230MP, C118S725000
Reexamination Certificate
active
06596133
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates in general to the field of fabrication of microelectronic devices, and more specifically, to an apparatus and method for depositing thin film material layers using physical-vapor deposition techniques.
BACKGROUND OF THE INVENTION
Physical-vapor deposition (PVD) techniques are widely used for thin-film deposition processes in microelectronics device fabrication. For instance, the PVD processes are extensively used for thin-film deposition processes for fabrication of semiconductor integrated circuits, magnetic data storage media and thin-film heads, flat-panel displays, and photonic devices. One PVD technique is plasma sputtering which employs a sputtering target placed in a vacuum processing chamber. By applying an electrical (DC or RF) bias to the sputtering target while maintaining a low gas pressure e.g., such as argon gas, within the process chamber, a plasma discharge is produced. The energetic ions from the plasma discharge (e.g., argon ions) bombard the sputtering target surface and generate a sputter flux of the target material. The sputter flux from the target material results in formation of a thin film on a substrate placed within the vacuum process chamber with a view of the sputtering target.
One application of PVD including plasma sputtering is fabrication of copper metallization for silicon chips. PVD of copper can be utilized to form a thin copper seed prior to subsequent copper deposition by electroplating and/or chemical-vapor deposition (CVD). One solution to the difficulties of CVD of copper films is to first deposit a thin seed layer on the substrate to reduce nucleation time and provide better adhesion, and then deposit bulk copper with CVD on top of the seed layer. For instance, PVD of copper provides a uniform and homogeneous seed film with no nucleation delay, good adhesion and negligible contamination with a clean PVD system. Thin film processing systems by PVD generally include a processing chamber with a support for a substrate wafer and a target for depositing material onto the substrate. Typically, atoms are ejected from the surface of a target comprised of the desired deposition material using a number of techniques, such as radio frequency (RF) diode sputtering, magnetron (DC or RF) sputtering, bias sputtering, or other PVD techniques. The ejected atoms are transported to the substrate via a sputter flux where they condense, forming a thin film.
Typical plasma sputtering processing chambers have a single PVD target for depositing a single layer of a desired target material onto a substrate, with the target typically disposed along the central axis of the process chamber and opposed to the substrate. However, manufacturing semiconductor devices often requires depositing multiple layers of different material layers onto a substrate, usually with different deposition techniques. Conventional PVD process chambers that have only a single target are mostly unable or have limited capability to deposit thin films of different materials or to apply different deposition techniques during a single in-situ process. Instead, in order to deposit multiple layers of different materials or to integrate PVD deposition with other deposition techniques, substrates are typically transferred between different process chambers connected either to a cluster tool central wafer handler or along an in-line sputtering system.
Systems for depositing multiple films of different materials onto a substrate typically include multiple processing chambers and an assembly to transport the substrate from one processing chamber to the next. The addition of a transfer assembly or a central wafer handler and multiple processing chambers increases the system cost and complexity, and further decreases wafer processing throughput due to the time spent transferring substrates. Also, the transport of wafers from one processing chamber to the next one presents the risk that contaminants such as particles will be introduced to the substrate, reducing the fabrication yield of a PVD system as substrates are ruined by the contaminants during processing. For example, after a deposition operation, contaminants and particles within the transfer assembly or the substrate support may break off when the transfer assembly robot moves or transfers the substrate. These dislodged particles may then be introduced to a substrate and further contaminate processing operations. To address this problem, the deposition chamber and central wafer handler must be serviced, thereby slowing process flow and consuming valuable time and resources.
One potential solution to the problems related to the deposition of multiple thin film layers is to provide multiple sputtering target electrodes in a single processing chamber. For instance, targets of different material types may be affixed to the lid of a processing chamber with the type of material deposited depending upon the target that receives power. Alternatively, the substrate or target may be moved to align with each other as disclosed by U.S. patent application Ser. No. 09/067,143, entitled “Apparatus and Method for Multi-Target Physical-Vapor Deposition of a Multi-Layer Material Structure,” by Moslehi, et al. However, processing chambers with multiple target electrodes may result in contamination of targets and substrates by the material of the different targets, thereby affecting process reliability and repeatability. For example, in a single chamber with more than one target, deposition from a first target may cross contaminate a second target when material from the first target interacts with the second target. The second target is then contaminated with material from the first target, thereby effecting process repeatability and cleanliness.
SUMMARY OF THE INVENTION
Therefore, a need has arisen for a deposition apparatus and method that supports physical-vapor deposition of a material onto a substrate with a target distal from the central axis region of a processing chamber.
A further need exists for a deposition apparatus and method for physical-vapor deposition from plural fixed targets onto a substrate in a single processing chamber.
A further need exists for an apparatus and method for depositing plural materials from plural targets in a single deposition chamber in which target and substrate movement are minimized to reduce the risk of contamination.
A further need exists for an apparatus and method that combines physical-vapor deposition and chemical-vapor deposition techniques in a single processing chamber to deposit one or more materials on a substrate.
A further need exists for an apparatus and method that combines one or more of physical-vapor deposition, ion beam deposition and chemical-vapor deposition techniques for thin film deposition of one or more materials in a single processing chamber.
A further need exists for an apparatus and method that supports atomic layer deposition of copper with chemical-vapor deposition using a copper-based precursor.
A further need exists for an apparatus and method that subjects a chemical-vapor deposition precursor to energetic species that aid in the disassociation of material from the precursor for deposition of material on a substrate at reduced processing temperatures.
In accordance with teachings of the present invention, an apparatus and method of use are provided that substantially eliminate or reduce disadvantages or problems associated with previously developed thin material film deposition apparatus and methods. More effective use of processing chamber space allows deposition using plural materials and plural deposition techniques within a single processing chamber.
In one embodiment, a PVD target offset from the central axis of the processing chamber avoids interference with material deposition from a primary PVD target or a CVD showerhead, or treatment of deposited material with an ion beam from an ion source. More specifically, an annular-shaped PVD target assembly is disposed between a substrate and a primary deposition source, such as a PV
Moslehi Mehrdad M.
Paranjpe Ajit P.
Baker & Botts L.L.P.
CVC Products Inc.
McDonald Rodney G.
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