Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/04—Cleaning involving contact with liquid

Definitions

• the present invention relates generally to plasma processing and plasma processing chamber components. More particularly, the present invention relates to methods of cleaning electrode assembly components containing plenums and to cleaning fixtures for facilitating these methods.
• plasma processing chambers are used to process substrates by a variety of techniques including, but not limited to, etching, physical vapor deposition, chemical vapor deposition, ion implantation, resist removal, etc.
• one type of plasma processing chamber contains an upper electrode, commonly referred to as a showerhead electrode, and a bottom electrode. An electric field is established between the electrodes to excite a process gas into the plasma state to process substrates in the reaction chamber.
• showerhead electrodes and other components of plasma processing chambers are commonly provided as assemblies of multiple components. Many of these components include plenums for directing or containing a process fluid or are configured to form fluid plenums in association with other components of an assembly. Regardless of the shape, size, or function of the particular fluid plenum at issue, the present inventors have recognized a significant need for improved methods and associated hardware for cleaning assemblies and components including fluid plenums.
• a method of cleaning one or more fluid plenums of an electrode assembly is provided.
• a plurality of fluid ports in communication with the fluid plenum are isolated and differentiated into respective sets of plenum input ports and plenum output ports.
• the input and output ports are engaged with respective cleaning fluid couplings.
• the pressure differential AP is large enough to force cleaning fluid from the cleaning fluid supply duct to the cleaning fluid waste duct through the fluid plenum.
• a cleaning fixture for cleaning fluid plenums of an electrode assembly is provided.
• the cleaning fixture comprises one or more cleaning fluid supply ducts, one or more cleaning fluid waste ducts, and one or more cleaning fluid couplings.
• the cleaning fluid couplings of the cleaning fixture are configured to engage and form respective sealed interfaces with the input and output ports of a fluid plenum of an electrode assembly.
• Fig. 1 is an isometric view of an electrode assembly including a sub- surface fluid plenum
• FIGs. 2 and 3 are schematic illustrations of relatively simple fluid plenum configurations and cleaning fixtures according to particular embodiments of the present invention engaged there with;
• Figs. 4 and 5 illustrate the manner in which alternative target cleaning fluid flow patterns can be created through variable designation of input, output, and closed plenum ports
• Fig. 6 is a schematic illustration of a plasma processing chamber.
• the plasma processing chamber 10 comprises a vacuum source 20, a process gas supply 30, a plasma power supply 40, a substrate support 50 including a lower electrode assembly 55, and an upper electrode assembly 100.
• the electrode assembly 100 comprises a thermal control plate 110, a showerhead electrode 120, and an interface layer 130 for facilitating a secure bond between the thermal control plate 110 and the showerhead electrode 120.
• One or more fluid plenums 140 are provided in the thermal control plate 110 to direct process gas from the process gas supply 30 to showerhead electrode passages in the showerhead electrode 120.
• the plenums 140 in the thermal control plate 110 typically direct process gas from the backside of the electrode assembly 30 to an array of small holes provided along the frontside of the showerhead electrode 120, as is illustrated schematically by the directional process gas flow arrows in Fig. 6. It is also noted that a variety of teachings may be relied upon in the design of electrode assembly components including, but not limited to, U.S. Pub. No. 2005/0133160.
• the thermal control plate 110, the showerhead electrode 120, or both may comprise one or more sub- surface fluid plenums 140 that can be configured to provide for circulation of a heat transfer fluid in the electrode assembly to help control the temperature of the assembly.
• the interface layer 130 is presented as an illustrative example and may comprise an adhesive bonding material, a thermally conductive gasket, or any other structure that facilitates assembly of the electrode assembly 100. It is contemplated that a variety of sealing members and securing hardware can be used to secure the thermal control plate 110 to the showerhead electrode 120. It is also contemplated that the securing hardware may also be selected to permit disengagement of the thermal control plate 110 and the showerhead electrode 120. In any event, the interface layer 130 and the general two-part structure of the electrode assembly 100 are presented for illustrative purposes only and should not be used to limit the scope of the present invention to any particular electrode assembly structure. Rather, cleaning fixtures and cleaning methods according to particular embodiments of the present invention typically only require the presence of some type of fluid plenum in an electrode assembly 100.
• the electrode assemblies 100 illustrated schematically in Figs. 1- 5 each include one or more sub- surface fluid plenums 140 and a plurality of fluid ports 150 in communication with the fluid plenums 140.
• the scope of the present invention should not be limited to the particular plenum configurations illustrated in Figs. 1-5.
• the illustrated configurations are merely presented to illustrate the concepts of the present invention as they relate to plenum cleaning. Indeed, it is contemplated that the concepts of the present invention will be applicable to a variety of plenum configurations of varying complexity, -A- including those where isolated fluid ports 150 are in communication with distinct portions of a common fluid plenum 140, as is illustrated in Fig. 1, or those where isolated fluid ports are in communication with independent fluid plenums.
• fluid ports are differentiated into respective sets of plenum input ports 150A and plenum output ports 150B.
• the input and output ports 150A, 150B are engaged with respective cleaning fluid couplings 152 that are configured to form a sealed interface with the port with which it is engaged.
• a cleaning fluid from a cleaning fluid reservoir 160 is directed through the fluid plenum 140 by providing one or more cleaning fluid supply ducts 154 in communication with the plenum input ports 150A and one or more cleaning fluid waste ducts 156 in communication with the plenum output ports 150B.
• the pressure differential AP is large enough to force cleaning fluid from the cleaning fluid supply ducts 154 to the cleaning fluid waste ducts 156 through the fluid plenum 140. Care may also be taken to maintain the pressure differential AP below the pressure differential failure threshold of the sealed interfaces of the plenum fluid input and output ports 150A, 150B. In addition, it may also be preferable to maintain the respective pressures P IN ,P 0UT at the plenum input and output ports 150A, 150B below the absolute pressure failure thresholds of the sealed input and output port interfaces.
• cleaning fluid may be forcibly directed through the fluid plenum 140 while isolating the cleaning fluid exclusively to the fluid plenum.
• the nature of the cleaning process is such that the cleaning operation may be executed prior to, during, or following fabrication and construction of the electrode assembly 100.
• the forcible nature of the cleaning operation also reduces the likelihood that particles will remain trapped within the fluid plenum 140 and serve as a source of contamination in the plasma processing chamber 10 illustrated in Fig. 6.
• the fluid ports 150 can be further differentiated into a set of one or more closed plenum ports 150C to help tailor the cleaning fluid flow pattern within the fluid plenum 140, as is evident in comparing the directional arrows within the respective fluid plenums 140 of Figs.
• fluid flow patterns may be created by altering the respective positions of the plenum input ports 150A, the plenum output ports 150B, and the closed plenum ports 150C.
• Particular target patterns may be selected for creating an optimum distribution of the cleaning fluid within the fluid plenum 140.
• alternative target cleaning fluid flow patterns may be selected to cooperate with one or more subsequent cleaning fluid flow patterns to ensure adequate coverage of the various portions of a fluid plenum.
• the cleaning fluid flow pattern defined by the plenum input ports 150A, the plenum output ports 150B, and the closed plenum ports 150C in Fig. 4 directs a significant amount of cleaning fluid through the majority of the plenum 140 but also tends to leave relatively inactive fluid plenum portions 140A, 140B, which may be insufficiently cleaned by the flow of cleaning fluid within the plenum 140.
• the cleaning fluid may be directed through the fluid plenum by varying the manner in which the fluid ports are differentiated into respective sets of input and output ports. More specifically, referring to Fig. 5, the respective locations of the plenum input ports 150A, the plenum output ports 150B, and the closed plenum ports 150C can be altered from those illustrated in Fig. 4 to direct cleaning fluid through the formerly inactive fluid plenum portions 140A, 140B before or after the cleaning operation illustrated in Fig. 4 is executed.
• the aforementioned variation in the manner in which the fluid ports 150 are differentiated into respective input, output, and closed ports can be executed by controlling respective valves associated with each cleaning fluid coupling 152.
• the variation in fluid port differentiation can be executed by using a programmable controller 180 to control a fluid router in communication with the cleaning fluid reservoir 160 and the cleaning fluid supply ducts 154.
• the cleaning fluid reservoir 160 is also illustrated in Figs. 2 and 3 as a receptacle for used cleaning fluid.
• the cleaning fluid can be directed through the fluid plenum 140 by interchanging the respective sets of input and output ports so as to execute at least one input/output port swapping operation characterized by a repeated series of back-and- forth, swapped cleaning pulses flowing through the fluid plenum 140.
• the cleaning fluid can be directed through the fluid plenum 140 at a varying flow rate to simulate a series of cleaning fluid pulses.
• the cleaning fluid can be directed through the fluid plenum 140 with a turbulence-generating gaseous medium, such as nitrogen or filtered air.
• FIGS. 2 and 3 also illustrate the use of a cleaning fixture 170 to fix the relative positions of the engaged cleaning fluid couplings 152 and enable convenient transition of successive, similarly configured electrode assemblies 100 to a plenum cleaning station employing the cleaning fixture 170 and the associated cleaning fluid couplings 152.
• a cleaning fixture 170 to fix the relative positions of the engaged cleaning fluid couplings 152 and enable convenient transition of successive, similarly configured electrode assemblies 100 to a plenum cleaning station employing the cleaning fixture 170 and the associated cleaning fluid couplings 152.
• the cleaning fixture 170 can be configured to permit the respective positions of the fixed cleaning fluid couplings 152 to be varied to match those of the fluid ports 150.
• the process gas from the backside of the electrode assembly 30 is directed to an array of small holes provided along the frontside of the showerhead electrode 120.
• a cleaning fixture blocking plate 175 configured to prevent the dispersal or loss of cleaning fluid through the array of process gas holes in the showerhead electrode 120 to help maintain the integrity and precision of the cleaning operation.

Landscapes

• Drying Of Semiconductors (AREA)
• Cleaning In General (AREA)
• Cleaning Or Drying Semiconductors (AREA)
• Cleaning By Liquid Or Steam (AREA)
• Chemical Vapour Deposition (AREA)

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• 2007
  • 2007-10-09 US US11/869,340 patent/US7736441B2/en not_active Expired - Fee Related
• 2008
  • 2008-09-09 KR KR1020107010167A patent/KR101555389B1/ko active Active
  • 2008-09-09 JP JP2010528919A patent/JP5579068B2/ja not_active Expired - Fee Related
  • 2008-09-09 WO PCT/US2008/075675 patent/WO2009048702A1/en not_active Ceased
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