Plasma processing chamber having magnetic assembly and method

#Embodiments of the present invention relate to a plasma processing chamber having a magnetic assembly and methods of manufacture.

#A plasma processing chamber exposes a substrate to a plasma capable of processing the substrate. Typically, the chamber comprises a substrate support to support the substrate, a gas distributor to introduce process gas into the chamber, and a gas exhaust to exhaust the gas from the chamber. In certain chambers, a magnetic assembly is used to control the passage of plasma species into an exhaust channel of the chamber that may extend around the substrate support and is used to exhaust process gas from the chamber. For example, the magnetic assembly may be used to limit the passage of charged plasma species into the exhaust channel. The magnetic assembly may also be positioned around the substrate support to generate a magnetic field about the support to localize, excite, or contain the plasma, in or about the substrate processing zone in the chamber.

#One type of magnetic assembly comprises a housing in which a number of permanent magnets are positioned as for example described in commonly assigned U.S. patent application No. 6,074,512 filed on Jul. 15th, 1997 to Collins et al. The magnets are sealed in an epoxy medium to prevent movement of the magnets within the housing. Typically, as shown in FIG. 1, the housing has a top or bottom opening 15 that is sealed by a cover plate 20 that is welded along its edges 21 to the sidewalls of the housing 22. However, the welded interface 21 between the cover plate 20 and the housing 22 can erode when exposed to the plasma in the chamber. When holes are formed in the weld lines 21 or adjacent portions of the housing, the material inside the housing 22, such as the epoxy that is used to hold the magnets 25 in place, can burn or otherwise deteriorate having undesirable effects on the substrate being processed and the magnetic assembly itself. For example, the magnets 25 can become damaged when the plasma 17 penetrates into the housing 22. Permanent magnets which are made of rare earth containing materials are expensive and it would be desirable to remove the magnets from a damaged magnetic assembly and reuse the magnets. Thus it is desirable to have a magnetic assembly and housing that is more resistant to plasma erosion and that can be more easily used in refurbishment processes.

#These features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings which illustrate examples of the invention. However, it is to be understood that each of the features can be used in the invention in general, not merely in the context of the particular drawings, and the invention includes any combination of these features, where:

#FIG. 1 (Prior Art) is a cross-sectional side view of a portion of a plasma processing chamber having a conventional magnetic assembly;

#FIG. 2 is a cross-sectional side view of a plasma processing chamber having an embodiment of a magnetic assembly according to the present invention;

#A semiconductor fabrication process may be used to deposit material on or etch a substrate 90 in a plasma processing chamber 100, such as for example, a DIELECTRIC ETCH MxP+ CENTURA chamber, commercially available from Applied Materials Inc., Santa Clara, Calif., as illustrated in FIG. 2. The particular embodiment of the process chamber 100 shown herein, which is suitable for processing of semiconductor substrates 90, is provided only to illustrate the invention, and should not be used to limit the scope of the invention. Other process chambers capable of energizing a process gas, for example an IPS chamber, also available from Applied Materials Inc., can also be used. Generally, the chamber 100 comprises a substrate support 205 having a surface to support the substrate 90 in a process zone 105 of the chamber 100. The substrate support 205 may comprise a quartz dielectric ring 290 that surrounds the substrate 90 to protect the underlying surface of the support 205 from the plasma. The substrate 90 is held in place during the process using a mechanical or electrostatic chuck having a receiving surface with grooves (not shown) in which a coolant gas, such as helium, is held to control the temperature of the substrate 90. The chamber 100 encloses a process zone 105 with, for example, a top wall 310 and side walls 320. An aperture 300 in the chamber 100, such as in a side wall 320 as shown, is provided to allow the substrate 90 to be transferred into and out of the chamber 100.

#For example, to perform an etching process, the process chamber 100 is evacuated to a pressure of less than about 1 mTorr, and a substrate 90 is transferred to the substrate support 205 from a load lock transfer chamber (not shown), which is also at vacuum. The chamber 100 comprises a gas supply 295 to maintain a process gas at a suitable pressure in the chamber 100. In one embodiment, the process chamber 100 is maintained at a pressure ranging from about 1 to about 1000 mTorr, such as from 10 to 300 mTorr. The process gas is introduced into the chamber 100 through a gas distributor 285 of a gas supply 295 comprising one or more gas lines 296 that connect a process gas source 298 to an inlet manifold 294 of the gas distributor 285 that conveys process gas through apertures 293 into the process zone 105. The gas distributor 285 may comprise a showerhead plate that is located above the substrate 90 and is made from a dielectric material.

#The chamber 100 further comprises a gas energizer 280 to energize the process gas to process the substrate 90. Typically, the gas energizer 280 couples an electric field to the process gas in the process zone 105 to energize the process gas (i) inductively by applying an RF current to an inductor coil (not shown) encircling the process chamber 100, (ii) capacitively by applying an RF current to a cathode electrode 235 and an anode electrode 232, such as the side wall 320 (as shown), or (iii) both inductively and capacitively.