Precursor material delivery system with staging volume for atomic layer deposition

Abstract

A precursor delivery system includes a flow path from a precursor container to a reaction space of a thin film deposition system, such as an atomic layer deposition (ALD) reactor. A staging volume is preferably established between the precursor container and the reaction space for receiving at least one dose of the precursor material from the precursor container, and from which pulses are released toward the reaction space. A pulse control device is preferably interposed between the staging volume and the reaction space. A sensor may sense a physical condition in the staging volume for providing feedback to a controller of the precursor delivery system, for performance monitoring and control.

1 . A precursor delivery system for delivering pulses of a precursor material to a reaction space in a thin film deposition system, comprising: 
 a precursor container for holding a supply of precursor material;    a flow path extending from the precursor container and adapted to be coupled, in use, to the reaction space; and    a staging volume interposed in the flow path downstream from the precursor container and upstream from the reaction space, in use, for receiving at least one dose of the precursor material from the precursor container, the staging volume being selectively isolatable from the precursor container, and the staging volume being selectively isolatable from the reaction space for releasing a series of pulses of the precursor material from the staging volume toward the reaction space;    a pulse control device interposed between the staging volume and the reaction space, in use, the pulse control device adapted to selectively release pulses of the precursor material from the staging volume toward the reaction space via the flow path; and    a sensor coupled to the staging volume for sensing a physical condition in the staging volume.    
   
   
       2 . The system of  claim 1 , further comprising a controller coupled to the sensor and responsive to the sensor for controlling the operation of the precursor delivery system.  
   
   
       3 . The system of  claim 1 , further comprising a controller coupled to the sensor for monitoring the precursor delivery system.  
   
   
       4 . The system of  claim 1 , further comprising a controller coupled the pulse control device for automatically controlling the operation of the pulse control device, the controller being responsive to an output of the sensor representative of the physical condition in the staging volume.  
   
   
       5 . The system of  claim 1 , in which the sensor includes a pressure transducer.  
   
   
       6 . The system of  claim 1 , in which the sensor includes a temperature sensor.  
   
   
       7 . The system of  claim 1 , in which the pulse control device includes a pulse valve.  
   
   
       8 . The system of  claim 7 , in which the pulse control device further includes a diffusion barrier operably connected to the flow path downstream from the pulse valve for preventing leakage from the pulse valve from reaching the reaction space.  
   
   
       9 . The system of  claim 1 , in which the pulse control device includes an inert gas valve operably coupled to the flow path.  
   
   
       10 . The system of  claim 1 , further comprising a particle filter interposed between the precursor container and the staging volume for filtering particles from the precursor material.  
   
   
       11 . The system of  claim 10 , in which the particle filter includes a high conductivity particle filter, the high conductivity particle filter including at least one inertial trap adjacent the flow path for filtering particles from the precursor material without significantly restricting flow of the pulses through the flow path.  
   
   
       12 . The system of  claim 1 , further comprising an isolation valve interposed in the flow path between the precursor container and the staging volume for selectively isolating the staging volume from the precursor container.  
   
   
       13 . The system of  claim 1 , further comprising a heater thermally associated with the precursor container for vaporizing at least a portion of the precursor material.  
   
   
       14 . The system of  claim 1 , further comprising a vacuum source coupled to the precursor container via a vacuum flow path for controlling a pressure within the precursor container.  
   
   
       15 . The system of  claim 14 , further comprising a vacuum shut-off valve operably interposed between the vacuum source and the precursor container for selectively interrupting the vacuum flow path.  
   
   
       16 . The system of  claim 15 , further comprising a vacuum filter interposed in the vacuum flow path between the precursor container and the vacuum shut-off valve.  
   
   
       17 . The system of  claim 14 , further comprising an isolation valve interposed between the precursor container and the staging volume for sealing the flow path downstream from the precursor container to facilitate adjustment of the pressure in the precursor container via the vacuum source.  
   
   
       18 . The system of  claim 1 , further comprising a high conductivity particle filter interposed in the flow path between the precursor container and the reaction space, the high conductivity particle filter including at least one inertial trap adjacent the flow path for filtering particles from the precursor material without significantly restricting flow of the pulses through the flow path.  
   
   
       19 . The system of  claim 18 , in which the high conductivity particle filter further includes: 
 an inlet coupled to an upstream portion of the flow path;    an outlet coupled to a downstream portion of the flow path;    a filter passage in communication with the inlet and the outlet, the filter passage including multiple turns between the inlet and the outlet; and    in which the inertial trap communicates with the filter passage and is positioned in proximity to one of the turns so that the inertia of the particles causes the particles to travel into the trap as the precursor material flows through the filter passage through said turn, thereby preventing the particles from passing into the reaction space.    
   
   
       20 . The system of  claim 19 , in which at least some of the turns of the filter passage form a spiral.  
   
   
       21 . The system of  claim 19 , in which at least some of the turns of the filter passage are defined by a series of baffles between the inlet and the outlet.  
   
   
       22 . The system of  claim 18 , in which the flow path and the filter passage are bordered by surfaces that are passivated.  
   
   
       23 . The system of  claim 22 , in which a passivation of the surfaces is selected from the group consisting of oxides, nitrides, carbides, and mixtures thereof.  
   
   
       24 . The system of  claim 1 , further comprising a supply of inert boost gas coupled to the staging volume.  
   
   
       25 . The system of  claim 1 , in which the staging volume is sufficiently large so that the release of a single pulse of the precursor material from the staging volume causes a pressure inside the staging volume to decrease no more than 50 percent.  
   
   
       26 . The system of  claim 1 , in which the flow path is formed in one or more solid blocks of thermally conductive material, said one or more blocks together forming an elongate thermally conductive body extending from the precursor container to the reaction space.  
   
   
       27 . The system of  claim 26 , in which internal surfaces of the thermally conductive body bordering the flow path are passivated.  
   
   
       28 . The system of  claim 27 , in which a passivation of the internal surfaces is selected from the group consisting of oxides, nitrides, carbides, and mixtures thereof.  
   
   
       29 . The system of  claim 26 , further comprising at least one heater in thermal association with the thermally conductive body for maintaining a temperature gradient in the flow path that increases toward the reaction space.  
   
   
       30 . The system of  claim 1 , in which the flow path is bordered by surfaces having a passivation selected from the group consisting of Al 2 O 3 , ZrO 2 , HfO 2 , TiO 2 , Ta 2 O 5 , Nb 2 O 5 , AlN, ZrN, HfN, TiN, TaN, NbN, AlC, ZrC, HfC, TiC, TaC, NbC, and mixtures thereof.  
   
   
       31 . The system of  claim 1 , in which the thin film deposition system comprises an atomic layer deposition system.  
   
   
       32 . A method of delivering pulses of a precursor vapor to a reaction space in a thin film deposition system, comprising: 
 providing a supply of precursor material;    establishing a flow path from the supply of precursor material to the reaction space;    vaporizing at least a portion of the precursor material to form a precursor vapor;    accumulating at least one dose of the precursor vapor in a staging volume located downstream in the flow path from the supply of precursor material and upstream from the reaction space;    isolating the staging volume from the supply of precursor material;    sensing a physical condition in the staging volume; and    selectively releasing pulses of the precursor vapor from the staging volume through the flow path and toward the reaction space.    
   
   
       33 . The method of  claim 32 , further comprising controlling the release of the pulses based on the physical condition sensed.  
   
   
       34 . The method of  claim 32 , further comprising triggering an alarm in response to sensing a physical condition indicative of leakage in the precursor delivery system.  
   
   
       35 . The method of  claim 32 , in which the physical condition includes a fluid pressure within the staging volume.  
   
   
       36 . The method of  claim 32 , further comprising filtering parties from the precursor vapor as it passes through the flow path.  
   
   
       37 . The method of  claim 36 , in which the filtering of particles includes directing the precursor vapor through a filter passage having multiple turns, at least one of the turns being positioned in proximity to an inertial trap in communication with the filter passage so that inertia of particles carried into the filter passage by the precursor vapor causes the particles to travel into the trap as the precursor vapor flows through said turn.  
   
   
       38 . The method of  claim 32 , in which the vaporizing of the precursor material includes heating the supply of precursor material.  
   
   
       39 . The method of  claim 32 , further comprising storing the supply of precursor material in a precursor container and drawing a vacuum inside the precursor container.  
   
   
       40 . The method of  claim 39 , in which the drawing of the vacuum inside the precursor container is accomplished via a vacuum flow path that bypasses the reaction space.  
   
   
       41 . The method of  claim 40 , further comprising filtering particles from the vacuum flow path.  
   
   
       42 . The method of  claim 32 , further comprising accumulating multiple doses of the precursor vapor in the staging volume before commencing the release of the pulses.  
   
   
       43 . The method of  claim 32 , further comprising injecting an inert boost gas into the staging volume.  
   
   
       44 . The method of  claim 32 , further comprising establishing a positive temperature gradient in the flow path that increases toward the reaction space.  
   
   
       45 . The method of  claim 32 , in which the thin film deposition system comprises an atomic layer deposition system.